A Comparison of AASHTO Bridge Load Rating Methods (2011)

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16 This section summarizes the findings of the final analysis runs for the 1,500 bridges selected for this research. 3.1 Summary of Bridge Rating Analysis The work presented herein involved the analysis and rating of the superstructure elements in 1,500 bridges (3,043 gird- ers); an investigation of the rating factors for LFR and LRFR; and an analysis of the differences of those ratings. Addition- ally the reliability index was calculated to determine if it meets that assumed in the development of the Manual for Bridge Evaluation (MBE). The target reliability index assumed in the development of the MBE is dependent upon the type of vehi- cle. Table 4 shows the assumed target reliability index for each vehicle type. The bridges were analyzed using the BRASS analysis engines within Virtis. BRASS produces results using the NCHRP Project 12-50 Process Report IDs; these results are then concatenated and imported into a Microsoft Access data- base. For each of the 12 vehicles used in the analysis pre- sented herein, there are 32 databases containing LFR results and 32 databases containing LRFR results. Data were then extracted from the databases using software developed for this research to review critical rating factors for LFR and LRFR for each girder. Rating factors were obtained for moment and shear, and inventory, operating, legal, or permit depending upon the vehicle type. 3.1.1 Software Used for the Analysis/Data Gathering The number of bridges reviewed for this project required a great deal of automation, not only from the standpoint of ana- lyzing the structures but also the sifting through the results. In all, given the 1,500 bridges, 12 vehicles and two specifications, the data results of more than 73,000 analysis runs of the Virtis- BRASS engine were processed. A combination of existing analysis software and a data gatherer written for this project were used to accomplish these requirements. The two key soft- ware components are briefly described in the following sections. 3.1.2 Virtis/BRASS The software used for the analysis of the bridges is the AASHTO Virtis software version 6.1 which incorporates the Wyoming Department of Transportation BRASS analysis engine. Wyoming BRASS has a separate version of software for LFR and LRFR rating and analysis. The versions used for this project were: • BRASS Girder (LRFD) version 2.0.3 • BRASS Girder (LFD) version 6.0.0 Version 2.0.3 of BRASS Girder (LRFD) is not the version delivered with AASHTO Virtis 6.1.0. During the analysis of the Process 12-50 report IDs, it was noticed that BRASS was not producing the 12-50 analysis results for permit vehicles. Wyoming DOT graciously provided the revisions needed for the additional 12-50 results on a later version of the BRASS LRFR software than that provided in Virtis 6.1.0. 3.1.2.1 Reliability Index Output Generator The RIO generator was developed to sort the Process 12-50 data produced by Virtis and BRASS. The detail of the for- mat of the CSV file produced by this software is described in more detail in Appendix R. The interface of the software is fairly simple and is illustrated in Figure 18. The software provides the ability to extract information as needed for the Process 12-50 results so that the raw data can be imported into a spreadsheet for use in calculating the reliability indices as well as comparing and sorting the data to develop trends. The data can also exclude specific rating report IDs C H A P T E R 3 Findings and Applications

if necessary and can process multiple databases at a time. The output of the software is a 138-column comma-delimited file with 4 lines of data produced for each bridge girder as follows: • Moment-Inventory • Moment-Operating • Shear-Inventory • Shear-Operating The final format for the comma-delimited file is shown in Appendix R. Each vehicle database is run through RIO. 3.1.3 Final Bridge Breakdown This section and Appendix A serve as a summary of the final bridge/girder selection used for this project. Using the methods described in previous sections, the research team attempted to break down the bridge types and materials used for the analysis on this project based on the 2008 FHWA NBI. Using a cross section of the NBI along with the available Virtis bridge data provided by the states, 1,500 bridges (3,043 girders) were selected for the final analysis and review. The bridges were subdivided by material type, configura- tion, year built and span length in an attempt to match the NBI 17 xednIytilibaileRepyTelciheV 5.3gnitaRyrotnevnI–daoLngiseD 5.2sdaoLlageL 5.2stimrePenituoR 5.2detrocsE–stimrePlaicepS Special Permits – Single or Multiple Trips mixed with traffic 3.5 Table 4. Assumed target reliability index, . Figure 18. RIO generator.

as closely as possible. During the analysis process, bridges were discarded if the process required hand calculations to provide missing LRFR input. An example would be the manual calcu- lation of LRFR distribution factors for supports with unequal skews. The distribution factor calculation provided in BRASS was used unless the input provided by the states included distribution factors. The final bridge breakdown for various parameters is pro- vided in the Figures 19–23. The final list of bridges (by girder) is provided in Appendix A. 3.1.4 Live Loads The ratings were performed for the design loads, HS20 for LFR and HL-93 for LRFR, as well as for eight other vehicles that were selected earlier in the project. The eight state vehicles selected for this project were divided into different categories present in the MBE. Five vehicles were classified as “Routine Permit” vehicles and are shown in Table 5. The other three vehicles were classified as “Special or Limited Permit” vehi- cles and are shown in Table 6. The three AASHTO legal loads, Type 3, Type 3-3, and Type 3S2, are now included and shown in Table 7. Table 8 shows how the eight vehicles are used in completing ratings by their respective states. Five of the vehicles (DE-07, FL-04, NC-21, NM-04, and TX-04) are used as posting vehi- cles. Three of the vehicles are used as vehicles for determining the operating rating (FL-04, NM-04, and OR-06) and NM-04 also is used for inventory rating. Two vehicles are classified as “permit trucks” by their respective state (IL-01 and WA-02). The current MBE rating provisions specify the number of lanes to be loaded by routine permit and special permit vehicles, but does not explicitly specify the number of lanes loaded by the HL-93 loading and AASHTO legal trucks. As the HL-93 loading and the AASHTO legal trucks represent typical com- mercial traffic, the critical distribution factor, single lane or multiple lanes loaded, was used for these loads. For routine permit vehicles, the MBE provisions require that the multiple lane distribution factor be used. For special permit vehicles, the MBE provisions require using a single lane distribution factor without the 1.2 multiple presence factor. Table 9 shows the live load factors applicable for what the MBE terms “routine commercial vehicles,” which are the AASHTO Legal Loads shown in Table 7. Table 10 shows the live load factors for “routine or annual permit vehicles” and for “special or limited permit vehicles.” When the truck weight is less than 100 kips, the routine permit load factors approach those used for the legal load rating. The live load factors used for the various types of vehicles in this study are provided in Table 11. An ADTT of 1,000 is used 18 Bridge Type Total # Girders Percent % Mult-girder built up 29 0.95 Multi-girder rolled beam 1,056 34.70 Multi-girder steel plate 374 12.29 Prestressed box beam 381 12.52 Prestressed I beam 704 23.14 Reinforced concrete slab 204 6.70 Reinforced concrete T beam 295 9.69 Total 3,043 100.00 Figure 19. Bridge type (final 12-78 breakdown).

19 Bridge Material/ Span Configuration Total # Girders Percent % Prestressed multispan 238 7.82 Prestressed simple span 847 27.83 Reinforced concrete multispan 105 3.45 Reinforced concreted simple span 394 12.95 Steel multispan 418 13.74 Steel simple span 1,041 34.21 Total 3,043 100.00 Figure 20. Bridge material/span configuration (final 12-78 breakdown). Figure 21. Exterior-interior girder (final 12-78 breakdown).

for all graphs except where all different ADTTs are presented to show the effect of the ADTT. In performing the analysis, the BRASS/Virtis input files provided by several states were analyzed without any revisions, except those necessary for the LRFR rating to be completed, as they were thought to represent a cross-section of the exist- ing bridge population. A problem with these input files was discovered during review of the results; the ADTT was input as zero for 91.5% of the girders analyzed. Figure 24 shows the percentage of girders in each ADTT range for each bridge type. Virtis/BRASS uses this ADTT to determine the load fac- tor for the legal and permit load ratings. The bridges were first analyzed for the 11 legal or permit vehicles used in this work using the applicable load factor based on ADTT for LRFR, generally 1.4, from Table 9. This load factor was applied by Virtis/BRASS as it corresponds to the load factor for com- mercial traffic when low ADTT exists. To include the effect of the ADTT on the rating factor com- parisons, the rating factors were modified in the spreadsheets developed for this project by multiplying by a ratio of load factors to adjust all ratings to the same ADTT. IL-01, OR-06, and WA-02 were treated as single trip special permit vehicles allowed to mix with other traffic. The other five permit vehi- cles are considered to be routine permit vehicles. Both types of permit vehicles as well as legal vehicles are assumed to have an ADTT = 1000. The effect of ADTT on the LRFR rating fac- tor is discussed in Section 3.4, but all results contained in the appendices are for ADTT = 1000. 3.2 Reliability Index Calculation Spreadsheet A spreadsheet was developed to compute reliability indices using the data obtained from BRASS. The reliability index calculation spreadsheet consolidates the results for each girder onto a single line representing the controlling rating factor and reliability index calculation. The data used in this spread- sheet is obtained from the RIO Generator program described earlier. Figure 25 shows a small portion of the Reliability Index Calculation spreadsheet. A similar spreadsheet was created for each type of bridge girder that was examined: simple span steel, simple span prestressed I-beam, simple span prestressed boxes, simple span reinforced concrete T-beams, simple span rein- forced concrete slabs, continuous span steel, continuous span reinforced concrete slabs, and continuous span prestressed I-beams. 20 Average Girder Spacing Total # Girders Percent% 0.0000<=Avg. Girder Spacing (ft)<1.500 0 0.00 1.500<=Avg. Girder Spacng (ft)<3.000 36 1.92 3.000<=Avg. Girder Spacing (ft)<4.500 289 15.40 4.500<=Avg. Girder Spacing (ft)<6.000 233 12.41 6.000<=Avg. Girder Spacing (ft)<7.500 580 30.90 7.500<=Avg. Girder Spacing (ft)<9.000 452 24.08 9.000<=Avg. Girder Spacing (ft)<10.500 138 7.35 10.500<=Avg. Girder Spacing (ft)<12.000 8 0.43 12.000<=Avg. Girder Spacing (ft)<13.500 141 7.51 13.500<=Avg. Girder Spacing (ft)<=15.000 0 0.00 Total 1,877 100.00 Figure 22. Average girder spacing-interior girders only (final 12-78 breakdown).

21 Y %tnecrePsredriG#latoTtliuBrae 97.0421191<tliubraeY=<0091 51.1532291<tliubraeY=<1191 06.50713391<tliubraeY=<2291 51.77124491<tliubraeY=<3391 84.77225591<tliubraeY=<4491 95.025266691<tliubraeY=<5591 12.612947791<tliubraeY=<6691 63.215738891<tliubraeY=<7791 59.514849991<tliubraeY=<8891 27.216830102=<tliubraeY=<9991 Total 3,035* 100.00 *Note: A small number of bridges had no “Year Built” input in Virtis Figure 23. Year built (final 12-78 breakdown).

22 Vehicle GVW (kips) Length (ft) Schematic DE-07 80 41 FL-04 80 67 NC-21 61 21 NM-04 55.2 22 TX-04 69 20 GVW=gross vehicle weight Table 5. Routine permit vehicles used in analysis. Vehicle GVW (kips) Length (ft) Schematic IL-01 120 44 OR-06 150.5 73.5 WA-02 207 70 13k 15k k5.12k5.12k5.12 11.5' 5.5' 4.5' 30' 21.5k 5' 21.5k 5' 15k 12' Table 6. Special or limited crossing permit vehicles. Vehicle GVW (kips) Length (ft) Schematic Type 3 50 19 Type 3-3 80 54 Type 3S2 72 41 Table 7. AASHTO legal vehicles.

23 Inventory Operating Posting Permit Routine Permit Vehicles DE-07 FL-04 NC-21 NM-04 TX-04 Special or Limited Crossing Permit Vehicles IL-01 OR-06 WA-02 Table 8. Use of rating vehicles. Traffic Volume (One direction) Load Factor for Type 3, Type 3S2, Type 3-3 and Lane Loads Unknown 1.80 ADTT ≥ 5,000 1.80 ADTT = 1,000 1.65 ADTT ≤ 100 1.40 ADTT=average daily truck traffic Table 9. Generalized live load factors, L for routine commercial traffic (MBE Table 6A.4.4.2.3a-1). Permit Type Frequency Loading Condition DFa ADTT (one direction) Load Factor by Permit Weightb Up to 100 kips ≥ 150 kips Routine or Annual Unlimited Crossings Mix with traffic (other vehicles may be on the bridge) Two or more lanes > 5000 1.80 1.30 = 1000 1.60 1.20 < 100 1.40 1.10 All Weights Special or Limited Crossing Single Trip Escorted with no other vehicles on bridge One Lane N/A 1.15 Single Trip Mix with traffic (other vehicles may be on the bridge) One Lane > 5000 1.50 = 1000 1.40 < 100 1.35 Multiple Trips (less than 100 crossings) Mix with traffic (other vehicles may be on the bridge) One Lane > 5000 1.85 = 1000 1.75 < 100 1.55 a DF = LRFD distribution factor. When one-lane distribution factor is used, the built-in multiple presence factor should be divided out. b For routine permits between 100 kips and 150 kips, interpolate the load factor by weight and ADTT value. Use only axle weights on the bridge. Table 10. Permit load factors, L (MBE Table 6A.4.5.4.2a-1). Vehicle LRFR Live Load Factor LFR Live Load Factor ADTT ≤ 100 ADTT = 1,000 ADTT ≥ 5,000 Design Vehicle (HL-93 or HS20) 1.75 2.17 Routine Permit Vehicles (DE-07, FL-04, NC-21, NM-04, TX-04) 1.4 1.6 1.8 1.3 Special Permit Vehicles (IL-01, OR-06, WA-02) 1.35 1.4 1.5 1.3 Legal Vehicles (Type 3, Type 3- 3, Type 3S2) 1.4 1.65 1.8 1.3 Table 11. Live load factors used in analysis.

3.2.1. Raw Data The raw data is obtained from RIO for each set of databases. This data includes the bridge name, girder number, a moment/ shear indicator, an inventory/operating rating, the vehicle name, and the controlling rating factors for LRFR and LFR. Using the controlling rating factors, the moments and shears are determined at the critical location. The raw data for each vehicle is combined on its own separate tab (#1 in Figure 25) and sorted by whether the results are for moment or shear. 3.2.2 Sorted Raw Data After the data is sorted, the data pertaining to the flexure and shear ratings are copied into separate spreadsheets for each vehicle (#2 in Figure 25). These spreadsheets are an intermedi- ate step between the raw data and calculating the reliability index. These spreadsheets are also linked to the “Rating Factor Comparison.” 3.2.3 Reliability Index Calculation A separate spreadsheet is used to calculate the reliability index for moment and shear (#3 in Figure 25). This spread- sheet references the appropriate columns from the spread- sheet containing the relevant sorted raw data (#2). The spreadsheet calculates the reliability index following the process used in calibrating the design specification and as presented in NCHRP Report 368. The main equation used to calculate the reliability index is shown here. The reliability index is calculated based upon the current section capacity for the actual reliability index. The required reliability index, shown only for the Design Vehicle, is the reliability index that would be obtained if the girder was designed for the load and load factors in the MBE. where: VR = coefficient of variation of resistance μQ = mean total applied load λRRn = mean unfactored resistance (actual) or mean fac- tored applied load (required) σq = standard deviation of total applied load β μ λ = −( ) + − ⎛ ⎝⎜ ⎞ ⎠⎟ ⎛ ⎝⎜ ⎞ ⎠⎟ − − 1 2 1 1 1 2 g g V LN V R V R R Q R n R 2 2 2 2 2 V R R q R N ( ) + ( ) σ λ Equation 1 24 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 < 100 100-1000 1001-5000 >5000 Pe rc en ta ge o f G ird er s ADTT Simple Span Steel Simple Span P/S Boxes R/C T-Beams Simple Span R/C Slabs Simple Span P/S I 2 Span - Steel 3 Span - Steel 4 Span - Steel Continuous Slabs 2 Span - Prestressed I 3 Span - Prestressed I Figure 24. Distribution of girders to ADTT categories. Figure 25. Reliability index calculation spreadsheet.

The mean total load is calculated by adding the mean live load plus impact load, the mean non-composite and compos- ite dead loads, and the mean wearing surface dead load. Equa- tion 2 shows the mean total load equation; μDC1 is taken as the mean due to girder self-weight and μslab is taken as mean due to all other dead loads except for the wearing surface. The standard deviation of the total load is calculated using Equation 3. The standard deviations for each load component are calculated using the mean load and coefficient of variation. The reliability index calculation used the following statisti- cal parameters for the resistance of the cross section, as shown in Table 12. The bias and COV for rolled shapes, prestressed I beams, and reinforced concrete T-beams are from NCHRP Report 368. The bias and COV for steel plate girders and built-up shapes, prestressed boxes, and reinforced concrete slabs were deter- mined for this project using available plans of existing example bridges and the statistical parameters for dimensions and materials. The bias and COV have not yet been determined for shear in built-up sections; the shear parameters for rolled shapes were used for the built-up shapes. Statistical parameters for shear in reinforced concrete slabs have not been provided as shear does not have to be checked as long as the flexural design is completed according to AASHTO LRFD 4.6.2.3. The relia- bility index for shear in reinforced concrete slabs utilizes the same statistical parameters provided for shear in reinforced concrete T-beams. The live load bias used in the calculation of the reliabil- ity index for the design, legal, and routine permit vehicles is provided in the tables below. The column of interest is “5 Years,” for the legal and routine permit vehicles while the 75-year column is used for the design load to be consistent with the AASHTO LRFD Design Specification. The appro- priate columns are applicable for all loading situations (sin- gle or multiple lanes loaded). The bias values from NCHRP Report 368 include a multiple presence factor of 1.2; the bias σ σ σ σ σQ LL IM DC slab DW= + + ++2 12 2 2 Equation 3 μ μ μ μ μQ LL IM DC slab DW= + + ++ 1 Equation 2 (shown in Tables 13, 14, and 15) used in this research has been divided by 1.2 as the multiple presence factor is included in the girder distribution factor. Tables 13, 14, and 15 are for ADTT = 1,000; additional tables are presented in NCHRP Report 368 for ADTT = 5,000. Such load is estimated to produce the highest load effect in the specified time period. The bias is determined for each bridge by interpolating between span lengths. Spans greater than 200 feet long use the bias for spans that are 200 feet long. Special permit vehicles were assumed to be deterministic and use a bias of 1.0 and a coefficient of variation of 0.0. The statistical parameters used for the different vehicle types are indicated in Table 16. The effect of using higher statistical parameters (bias and coefficient of variation) is a higher mean load and lower reliability index. To obtain the same target reli- ability index when higher statistical parameters are used, larger load factors will be required. The values necessary to calculate the reliability indices are shown in Appendix J for 20 girders/slabs of each type of bridge. For steel girders and prestressed boxes, 20 composite girders and 20 non-composite girders are shown. Results for both moment and shear are shown for all types even though shear does not have to be rated for concrete girders when a design rating is performed. The current load factors in the MBE assume that for rou- tine permit vehicles multiple lanes loaded will control in all situations. Therefore, the live loads from BRASS had to be cor- rected such that the load was from multiple lanes loaded even though for a particular girder a single lane loaded may control. For special or limited crossing permit vehicles, the MBE assumes that a single lane loaded will control all situations and the live loads from BRASS were adjusted accordingly. The load factors for special or limited crossing permit vehicles in the MBE account for the possibility of other vehicles being along- side the permit vehicle when on the bridge. The corrections were made as all ratings using Virtis were completed assuming that the vehicles were legal vehicles, not permit vehicles, and it was more efficient to multiply by a ratio than to rerun all the analyses. The design and legal vehicles used the critical number of lanes loaded. The following list shows the critical number of lanes for each type of vehicle: • Design and Legal Vehicles—single or multiple lanes loaded, whichever is critical 25 Bridge type Moment Shearbias COV bias COV Multi-girder steel rolled shapes 1.12 0.10 1.14 0.105 Multi-girder steel plate girders 1.08 M+, 1.05 M- 0.11 M+, 0.10 M- 1.13 0.16 Multi-girder steel built-up shapes 1.11 M+, 1.12 M- 0.123 X X Prestressed I Beam 1.05 0.075 1.15 0.14 Prestressed Box Beam 1.05 0.075 1.16 0.14 Reinforced concrete T beam 1.14 0.13 1.20 0.155 Reinforced concrete slab 1.13 0.13 -- -- Table 12. Statistical parameters for resistance.

26 Span (ft) 1 day 4 days 2 weeks 1 month 2 months 6 months 1 year 5 years 50 years 75 years 10 0.73 0.83 0.85 0.89 0.93 0.98 1.04 1.11 1.25 1.25 20 0.75 0.80 0.82 0.85 0.89 0.92 0.96 1.02 1.10 1.10 30 0.79 0.85 0.87 0.90 0.93 0.96 1.00 1.04 1.13 1.13 40 0.84 0.89 0.91 0.93 0.96 0.99 1.01 1.05 1.11 1.11 50 0.83 0.88 0.90 0.92 0.96 0.98 1.01 1.04 1.10 1.10 60 0.84 0.89 0.90 0.94 0.96 0.98 1.01 1.04 1.10 1.10 70 0.85 0.88 0.90 0.93 0.96 0.98 1.00 1.04 1.09 1.09 80 0.85 0.88 0.90 0.93 0.95 0.97 1.00 1.04 1.10 1.10 90 0.85 0.89 0.90 0.92 0.95 0.97 1.00 1.04 1.09 1.09 100 0.85 0.88 0.90 0.92 0.94 0.96 1.00 1.03 1.09 1.09 110 0.85 0.88 0.89 0.92 0.94 0.96 0.99 1.03 1.09 1.09 120 0.84 0.88 0.89 0.91 0.93 0.96 0.98 1.02 1.08 1.08 130 0.84 0.87 0.88 0.91 0.92 0.94 0.97 1.00 1.06 1.06 140 0.82 0.85 0.86 0.89 0.90 0.92 0.94 0.98 1.03 1.03 150 0.82 0.85 0.86 0.88 0.89 0.91 0.94 0.97 1.03 1.03 160 0.82 0.85 0.86 0.89 0.90 0.92 0.94 0.98 1.03 1.03 170 0.82 0.85 0.86 0.89 0.91 0.93 0.95 0.98 1.04 1.04 180 0.82 0.85 0.86 0.88 0.90 0.92 0.94 0.98 1.04 1.04 190 0.81 0.84 0.85 0.88 0.90 0.92 0.94 0.98 1.03 1.03 200 0.80 0.83 0.85 0.88 0.90 0.91 0.94 0.97 1.03 1.03 Mean Maximum Moments for Simple Spans Due to Multiple Trucks in One Lane (Divided by Corresponding HL-93 Moment) Table 13. Live load positive moment statistical parameters. Span (ft) 1 day 4 days 2 weeks 1 month 2 months 6 months 1 year 5 years 50 years 75 years 10 0.74 0.79 0.81 0.85 0.86 0.89 0.91 0.94 0.99 1.00 20 0.77 0.83 0.84 0.88 0.88 0.92 0.93 0.96 1.02 1.03 30 0.80 0.85 0.87 0.90 0.91 0.94 0.96 0.99 1.03 1.04 40 0.8 00.8 50.8 70.8 90.9 10.9 30.9 50.9 71.0 11.02 50 0.81 0.86 0.87 0.90 0.91 0.93 0.95 0.97 1.01 1.02 60 0.82 0.88 0.89 0.91 0.92 0.94 0.96 0.99 1.02 1.03 70 0.84 0.89 0.90 0.92 0.93 0.95 0.97 0.99 1.04 1.04 80 0.85 0.89 0.91 0.93 0.94 0.97 0.99 1.01 1.05 1.06 90 0.85 0.90 0.91 0.93 0.94 0.97 0.99 1.01 1.06 1.07 100 0.86 0.90 0.91 0.93 0.95 0.97 0.99 1.02 1.06 1.06 110 0.85 0.89 0.90 0.92 0.93 0.96 0.98 1.00 1.04 1.05 120 0.84 0.88 0.88 0.90 0.91 0.93 0.95 0.98 1.01 1.02 130 0.83 0.87 0.87 0.89 0.90 0.92 0.93 0.96 0.99 1.00 140 0.83 0.87 0.88 0.90 0.91 0.92 0.93 0.96 1.00 1.01 150 0.82 0.86 0.87 0.89 0.90 0.92 0.93 0.96 1.00 1.00 160 0.81 0.85 0.86 0.88 0.89 0.91 0.92 0.95 0.99 1.00 170 0.80 0.84 0.85 0.88 0.89 0.90 0.92 0.95 0.99 1.00 180 0.80 0.83 0.85 0.86 0.87 0.89 0.91 0.95 0.98 0.99 190 0.79 0.83 0.84 0.86 0.87 0.88 0.90 0.93 0.97 0.98 200 0.79 0.83 0.84 0.85 0.87 0.88 0.90 0.93 0.97 0.97 Mean Maximum Shears for Simple Spans Due to Multiple Trucks in One Lane (Divided by Corresponding HL-93 Shear) Table 14. Live load shear statistical parameters.

• Routine Permit Vehicles—two or more lanes loaded • Special or Limited Crossing Permit Vehicles—single lane loaded without multiple presence factor 3.3 Rating Factor Comparison Spreadsheet This spreadsheet is used to compile the bridge geometric characteristics, dead load moments and shears, and critical moment and shear locations for each girder. Additionally, for each live load (Design Vehicle, eight permit loads, and three legal loads), the LFR rating factor, LRFR rating factor, actual reliability index, and required reliability index for moment and shear are also compiled. The data is pulled into this spreadsheet from the reliability index calculation spreadsheet. LFR and LRFR Inventory Ratings are used for the Design Vehicle (HS-20 for LFR and HL-93 for LRFR) while LFR Operating Ratings and LRFR permit or legal ratings are used for the eight permit and three legal loads. This spreadsheet also compares the dead load moments and shears, live load moments and shears, as well as moment and shear resistance. Checking the ratio of unfactored dead load momentsandshears betweenLFR and LRFR allows verifying the results are being obtained at or near the same location and that the same dead loads are used in both methods. The rating fac- tor comparison spreadsheet contains the results for the Design Vehicle as well as for the eight permit and three legal loads. After obtaining all results, they are copied into a new sheet where they can be sorted without affecting the formulas extract- ing the data from the reliability index calculation spreadsheet. The results are sorted into four major categories (for some structure types not all four categories are applicable): • Interior girders with composite decks; • Interior girders with non-composite decks; • Exterior girders with composite decks; and • Exterior girders with non-composite decks. Following the sorting into the four major categories, the girders in each category are then plotted against the following bridge characteristics: • Year of construction • Span length 27 Span 1 day 4 days 2 weeks 1 month 2 months 6 months 1 year 5 years 50 years 75 years (ft) 10 0.79 0.88 0.92 0.94 0.97 0.99 1.03 1.09 1.09 20 0.86 0.93 0.95 0.95 0.97 0.99 1.02 1.05 1.06 30 0.91 0.96 0.98 0.99 1.01 1.02 1.04 1.06 1.07 40 0.92 0.98 0.99 1.00 1.02 1.04 1.05 1.08 1.09 50 0.94 1.00 1.01 1.02 1.04 1.06 1.07 1.10 1.11 60 0.88 0.94 0.95 0.96 0.98 0.99 1.01 1.04 1.04 70 0.86 0.92 0.93 0.94 0.96 0.97 0.98 1.01 1.02 80 0.85 0.91 0.92 0.93 0.95 0.96 0.98 1.01 1.01 90 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 100 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 110 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 120 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 130 0.85 0.90 0.91 0.92 0.94 0.95 0.97 0.99 1.00 140 0.85 0.90 0.91 0.92 0.94 0.95 0.97 0.99 1.00 150 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 160 0.85 0.90 0.91 0.92 0.95 0.95 0.97 1.00 1.00 170 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 180 0.85 0.90 0.91 0.92 0.94 0.95 0.97 1.00 1.00 190 0.85 0.90 0.91 0.92 0.94 0.95 0.97 0.99 1.00 200 0.86 0.90 0.91 0.92 0.94 0.95 0.97 0.99 1.00 Mean Max. Negative Moments for Continuous Spans Due to Multiple Trucks in One Lane (Divided by HL-93 Neg. Moment) Table 15. Live load negative moment statistical parameters. Vehicle Type Moment Shear Bias (λ) COV Bias (λ) COV Design Table 9 and Table 11 0.19 Table 10 0.19 Legal Table 9 and Table 11 0.19 Table 10 0.19 Routine Permit Table 9 and Table 11 0.19 Table 10 0.19 Special Permit 1.0 0.0 1.0 0.0 Table 16. Statistical parameters for different vehicle types.

• Skew Angle • Tributary width (for interior girders this is equal to the average girder spacing and for exterior girders this is equal to the overhang width plus one-half the spacing between the exterior girder and first interior girder) Scatter plots were created in an effort to observe trends within the data and how the results are affected by these differ- ent criteria: • Ratio of DC1 (unfactored dead loads applied to non- composite cross-section) (moment and shear) • Ratio of DC2 (unfactored dead loads applied to composite cross-section, does not include the wearing surface) and DW (wearing surface applied to composite cross section) (moment and shear) • Ratio of Unfactored Live Loads (moment and shear) • Ratio of Factored Live Loads (moment and shear) • Actual Reliability Indices (moment and shear) • Location of Critical rating factor (shear only) • LFR Rating (moment and shear) • LRFR Rating (moment and shear) • Ratio of LRFR Rating to LFR Rating (moment and shear) Table 17 shows the type and number of girders used in the analysis. There were 3,036 girders used in the analysis from eight different types of bridges. 3.3.1 Data Analysis and Trends As shown in the Appendices of this report, the amount of data analyzed was overwhelming. The results of different types of structures are similar in that there are no clear trends related to the criteria used (i.e., year of construction, skew angle, and tributary width, etc.) that can be used as a basis for possible revisions to the MBE. In the following appendices, the results for simple span steel structures are presented in more detail than for other types of structures presented in the subsequent sections. The appendices to this report contain comprehensive cov- erage of the results. For simple span steel girder bridges, the results are presented in Appendix B. The results in Appendix B are plotted against: year of construction, span length, tribu- tary width, and skew angle for interior composite girders. Span length and tributary width are used for the remaining cate- gories of simple span steel bridges. The results for other types of simple span structures, Appendix C through Appendix F, are shown plotted versus span length only. The results for continuous spans are shown in Appendix G through Appen- dix I, with the continuous steel and prestressed I-girder bridges shown plotted versus tributary width and continuous slabs shown plotted versus maximum span length in the bridge. Due to the lack of trends in all cases, it was concluded that the variable used for the horizontal axis of the graph, be it year of construction, skew angle, and tributary width, etc., did not actually matter. The results are contained in the following appendices: • Appendix B—Simple Span Steel I Girder Bridges – B.1—Interior Composite – B.2—Interior Non-Composite – B.3—Exterior Composite – B.4—Exterior Non-Composite • Appendix C—Simple Span Prestressed I Girder Bridges – C.1—Interior Composite – C.2—Exterior Composite • Appendix D—Simple Span Prestressed Box Girder Bridges – D.1—Exterior Composite – D.2—Exterior Non-Composite – D.3—Interior Composite – D.4—Interior Non-Composite • Appendix E—Simple Span Reinforced Concrete T-Beam Bridges – E.1—Exterior – E.2—Interior • Appendix F—Simple Span Reinforced Concrete Slab Bridges • Appendix G—Continuous Span Steel Girder Bridges – G.1—Interior Non-Composite – G.2—Interior Composite – G.3—Exterior Non-Composite – G.4—Exterior Composite • Appendix H—Continuous Span Reinforced Concrete Slab Bridges • Appendix I—Continuous Span Prestressed I Girder Bridges – I.1—Interior Composite – I.2—Exterior Composite 3.3.2 Main Sources of Difference in Rating Factors Between LFR and LRFR In some cases, significant differences in the rating factors cal- culated using the LFR and LRFR methodologies were observed 28 sredriGforebmuNepyTredriG 7301leetSnapSelpmiS Simple Span Prestressed Concrete I 467 Simple Span Prestressed Concrete Box 377 Simple Span Reinforced Concrete T-Beam 295 Simple Span Reinforced Concrete Slab 99 814leetSnapSsuounitnoC Continuous Span Reinforced Concrete Slabs 105 832IdessertserPnapSsuounitnoC Table 17. Girder type and number.

for individual bridges. In other cases there was a general trend of a reduction in the rating factors. These differences were investigated to determine the source of the differences. Here are the reasons for the differences: • Differences in unfactored dead loads: It was expected that for a particular girder the dead loads would be the same in both methods. However, it was observed that in approxi- mately 4% of the simple span steel girders, the distribution of the composite dead loads to the girders in the bridge cross section appeared to be done differently in the two methods (See Figure 26). Further investigation found the values calculated in BRASS were correct, but some of the values extracted using the NCHRP 12-50 process were not. Using the values calculated by BRASS, the Figure 26 shows that most girders have composite dead loads that are sim- ilar; the girders that were not similar have been removed from this graph. • Differences in live loads: The factored live loads for LRFR are typically greater than the LFR live loads for both moment and shear. Figures 27 and 28 show the ratio of fac- tored positive live load moment and factored negative live load moment, respectively, for the DE-07 vehicle. Figure 29 shows the ratio of factored live load shears for the DE-07 vehicle. The figures show that most girders have LRFR live loads that are greater than the LFR live loads for both moment and shear. The resistances and dead loads were similar for most types of girders resulting in the numerator 29 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1880 1900 1920 1940 1960 1980 2000 2020 Ra tio o f D C2 an d DW M o m e n ts (L RF R/ LF R) Year of Construction Figure 26. Ratio of unfactored LRFR composite dead loads to unfactored LFR composite dead loads. 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 200 400 600 800 1000 1200 Ra tio o f F ac to re d LR FR Li v e Lo ad Po si tiv e M o m e n t t o F ac to re d LF R Li v e Lo ad Po si tiv e M o m e n t Girders Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T Beam Simple Span RC Slab Continuous Span Steel Continuous RC Slab Continuous PS I Figure 27. Ratio of factored positive live load moments (LRFR/LFR) for DE-07 vehicle.

of the rating factor equation being similar. This indicates that the factored live loads are likely causing most girders to have lower ratings for LRFR than for LFR, in addition to the new rating criteria discussed below. • Atypical bridge characteristics: The calculations of loads for bridges with atypical geometry resulted in significant differences. Examples of these bridges are: – A simple span bridge with one square (zero skew) abut- ment and the second abutment having 35 degree skew angle. Figure 30 shows the plan of such a bridge. The results showed that the loads varied from girder to girder because each girder has a different length. This was caused by the load factors for live load in the LFR being the same for all girders (distribution factors are a function of the girder spacing only) while they were significantly differ- ent for LRFR (a function of span length, girder spacing, deck/beam relative stiffness). This bridge was removed from the set. – Bridges with sidewalks where the input assumed that the sidewalk may be removed and the entire width of the bridge is available to vehicular traffic for LFR and considered the effects of the sidewalk on the loads (lighter live load) in LRFR. Girder G4 in Figure 31 was a case where the presence of a sidewalk was ignored in the calculation of the distribution factor for LFR by the user. For LRFR, the distribution factor is calcu- lated by BRASS and considered the presence of the sidewalk. 30 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 100 200 300 400 500 Ra tio o f F ac to re d LR FR Li v e Lo ad N eg at iv e M o m e n t t o Fa ct o re d LF R Li v e Lo ad N e ga tiv e M o m e n t Girders Continuous Span Steel Continuous RC Slab Continuous PS I Figure 28. Ratio of factored negative live load moments (LRFR/LFR) for DE-07 vehicle. 0 1 2 3 4 5 6 7 8 0 200 400 600 800 1000 1200R at io o f F ac to re d LR FR Li v e Lo ad Sh e ar to Fa ct or e d LF R Li v e Lo ad Sh e ar Girders Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T Beam Simple Span RC Slab Continuous Span Steel Continuous RC Slab Continuous PS I Figure 29. Ratio of factored live load shears (LRFR/LFR) for DE-07 vehicle.

– Bridges with small girder spacing and thick decks. Such arrangement produces significantly different live load distribution factors for the two rating methods. When the effect of the thick deck and small girder spacing is combined with different treatment of the sidewalk, the difference in the rating factors is extreme. For example, for the bridge shown in Figure 31, the deck thickness exceeds that for which the LRFD distribution factor equations were developed and the girder spacing is at the limit of the applicability range. Following the distribution factor table in the AASHTO LRFD Design Specification, the distribution factor is determined using the lever rule and considering the limits imposed by sidewalks on the position of the traffic lanes. The LFR distribution factor is still deter- mined using S/5.5 ignoring the sidewalk and its effect on the location of the traffic lanes. The distribution factor for LFR is 0.64 wheel lines, i.e., 0.32 lanes, and for LRFR is 0.06 lanes. Within the simple span steel bridges, there were 118 girders with tributary widths less than 3.5 feet, 198 girders with a deck thickness of less than 4.5 inches, and 12 girders with a deck thickness greater than 12 inches. The 3.5 foot spacing and deck thickness limits of 4.5 to 12 inches are the limits on the range of applica- bility for the distribution factors from Table 4.6.2.2.2b-1 in the LRFD Design Specification. When the thin decks were investigated, it was found that several were timber decks that were erroneously input as concrete. • New rating criteria: The LFR required checking far fewer criteria than the LRFR. In many cases when a general trend of lower rating factors was observed, it was noticed that the lower LRFR ratings were generally controlled by a criteria not included or rarely controlled in LFR. Following are five examples for such cases. – Concrete structures: Rating of concrete beams and slabs for shear. In the LFR ratings, shear could be ignored for concrete elements but in the LRFR rating shear must be considered for permit vehicles and for the design and legal loads if signs of distress exist. Many of the Virtis input files for bridges with concrete superstructures had the shear rating turned off for both LFR and LRFR. The shear rating was turned on and shear ratings were considered and compared. Fig- ure 32 shows that the prestressed concrete I-girder LRFR ratings for shear are more scattered and of the 274 girders shown, 177 were controlled by the shear rating, not the moment rating. – The results for shear in steel girders: The LRFR shear rating factor for approximately one-third of the simple span steel bridge girders was controlled by the capacity of the bearing stiffener (NCHRP 12-50 Report ID 80007). 31 Figure 30. Atypical bridge characteristics. Figure 31. Bridge with characteristics outside of range of applicability for LRFD distribution factor equations.

This check was not typically performed in the LFR rat- ing. Figure 33 shows that ratings are generally lower when the capacity of the bearing stiffener was included in determining the controlling rating factor. The maximum difference in the value of the controlling rating factor including and ignoring the bearing stiffener rating is 88.3% with the average difference being 13.6%. Further investigation into the bearing stiffener ratings found that for LFR, the version of BRASS used in this project (Version 6.0.0) was calculating both the bearing resis- tance and axial resistance of the bearing stiffener but was incorrectly calculating the area used in the bearing resistance equation. In addition, further investigation by BridgeTech, the developer of BRASS, determined that the LFR rating was only considering the axial col- umn resistance, not both the bearing resistance and axial column resistance, in determining the bearing stiffener rating. These errors were corrected in later ver- sions of BRASS (Version 6.0.1 and later). After these errors were corrected, the resistance of the bearing stiffeners in both methods is very similar when all load factors are taken into account. Therefore, the dif- ference in the rating factor of the bearing stiffener in the two methods will be the same as the difference in the beam reaction. Due to heavier live loads in the LRFR, the reaction under the LRFR loads is expected to be approximately 20-40% higher than for LFD. – The results for flexure in prestressed I-girders and box girders, reinforced concrete T-beams, and reinforced concrete slabs were affected by including the effect of shear on the force in the longitudinal reinforcement near the ends of girders (NCHRP 12-50 Report ID 85004). 32 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0 50 100 150 200 250 300 LR FR R at in g # of Girders Moment Shear Figure 32. LRFR design load inventory ratings for simple span prestressed I-girders. 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0 50 100 150 200 250 300 350 400 450 LR FR R at in g Girders Does Not Include Report ID 80007 Includes Report ID 80007 Figure 33. LRFR design load shear rating factors for simple span steel bridges.

This Report ID returns the rating of the stress in the lon- gitudinal reinforcement required by Article 5.8.3.5 of the AASHTO LRFD. Figure 34 shows that ignoring the lon- gitudinal steel rating when determining the controlling rating leads to increased ratings for many girders. The maximum percentage difference is 86.3% of the rating ignoring Report ID 85004 and the average percent dif- ference is 20.2%. In addition to changing the ratings, the controlling section shifted towards the support and away from midspan. – Stresses in prestressed girders under service loads: It was determined that when the longitudinal steel rating is ignored, the service limit states control most girders with LRFR ratings less than 1.0. The service limit states are optional for legal and permit vehicles but are calculated by BRASS. There is an option within Virtis which allows the service stresses to be considered in determining the critical rating; if this box is not selected the critical rating will not consider the service stress ratings. All ratings are printed in the BRASS output as well as the NCHRP 12-50 Process output. Figure 35 shows the LRFR rating ignor- ing both the longitudinal steel rating and the Service III tensile stress rating, indicated by the blue diamonds, and the LRFR ratings where only the longitudinal steel is ignored, indicated by the red plus signs. The LRFR rating improves for most girders when the Service III tensile stress rating is ignored. The tensile service stresses are calculated for LFR but control significantly fewer girders. – Shear friction rating in composite concrete girders: The shear friction resistance between concrete girders and cast-in-place concrete decks was not checked in LFR. In LRFR, this is a design criteria specified in AASHTO LRFD Design Specification 5.8.4. The effect of ignoring 33 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0 100 200 300 400 500 LR FR R at in g Girders Does Not Include Report ID 85004 Includes Report ID 85004 Figure 34. LRFR design load moment ratings for simple span prestressed concrete I-beams. 0 1 2 3 4 5 6 7 8 9 0 100 200 300 400 500 LR FR R at in g Girders Ignoring Report IDs 85004 and 85107 Ignoring Report ID 85004 Figure 35. LRFR moment ratings for simple span prestressed concrete I-beams for WA-02 vehicle.

this criterion is shown in Figure 36. The LRFR rating when the shear friction is ignored is generally higher than when it is included. 3.4 Effect of ADTT and Permit Type on Ratings The effect of ADTT and type of permit on the LRFR rat- ings was investigated. Legal and routine permit ratings were determined for each ADTT category: greater than 5,000, equal to 1000, and less than 100. Special permit ratings were determined for each permit type within the special permit category and for each ADTT category. The special category types (listed in Table 10) are escorted, single trip mixed with other traffic, and multiple trip (less than 100 crossings) mixed with other traffic. The following sections present the percentage of girders with rating factors within each range for simple span steel bridges when all rating criteria are con- sidered. The graphs also show the distribution of the LFR rating for comparison of the LFR rating and the possible LRFR ratings using the current load factors in the MBE. Sim- ilar graphs for the remaining bridge types included in this study are shown in the appendices. In all cases covered by Tables 18 through 28 the rating factors drop with the increase in ADTT due to the increase in the corresponding load fac- tor for live load. Tables containing the distribution of rating factors for all bridge types and all permit and legal vehicles when all rating criteria and existing load factors are consid- ered are shown in Appendix K. Tables 18 through 28 show the percentage of girders with LFR and LRFR ratings within each range of rating factor, e.g., RF 0.9 to 1.0. If all girders of a specific girder type and for a particular ADTT category (ADTT < 100) have ratings greater than 1.0, then that bar will reach the top of the graph. As the ADTT increases (which results in higher load factor), the rat- ing factors drop, resulting in an increase in the percentage of girders in the lower ranges of the rating factors. 3.4.1 AASHTO Legal Vehicles The results for the three AASHTO legal vehicles are shown in this section. The live load factors used are those shown in Table 9 unless a service limit state was the controlling rating, in which case the rating does not depend upon the ADTT and a live load factor of 1.0 is used. Table 18 shows the percentage of girders within each range of ratings for the different ADTTs used in the MBE for the AASHTO Type 3 legal load. At least 90% of composite gird- ers had ratings above 1.0 for all ADTTs for both moment and shear. Non-composite girders have poor flexure ratings for all ADTT levels, but approximately 90% have satisfactory ratings for shear. Table 19 shows the percentage of girders within each range for the different ADTTs used in the MBE for the AASHTO Type 3-3 legal load. At least 90% of composite girders had rat- ings above 1.0 for all ADTTs for both moment and shear. Non- composite girders have poor flexure ratings for all ADTT levels with only 60% of girders having a flexure rating above 1.0 for an ADTT of less than 100. Approximately 90% of non- composite girders have satisfactory ratings for shear. Table 20 shows the percentage of girders within each range for the different ADTTs used in the MBE for the AASHTO Type 3S2 legal load. At least 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear. Non-composite girders have poor flexure ratings for all ADTT levels with less than 60% of girders having a flexure rating above 1.0 for an ADTT of less than 100. Approximately 85–95% of non-composite girders have satisfactory ratings for shear, 34 0 1 2 3 4 5 6 7 8 9 0 100 200 300 400 500 LR FR R at in g Girders Ignoring Report ID 85003 Including Report ID 85003 Figure 36. LRFR shear ratings for simple span prestressed concrete I-Beams for WA-02 vehicle.

35 ShearMoment Type 3 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 Table 18. AASHTO Type 3—LRFR ratings for different ADTT.

36 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment Type 3-3 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 19. AASHTO Type 3-3—LRFR ratings for different ADTT.

37 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment Type 3S2 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 20. AASHTO Type 3S2—LRFR ratings for different ADTT.

with higher ADTTs having a lower percentage of girders with ratings above 1.0. 3.4.2 Routine Permit Vehicles The results for the five vehicles treated as routine permits are shown in this section. The live load factors used are those shown in the upper portion of Table 10 unless a service limit state was the controlling rating, in which case the rating does not depend upon the ADTT and a live load factor of 1.0 is used. Table 21 shows the percentage of girders within each range for the different ADTTs used in the MBE for the DE-07 vehi- cle. At least 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear. Non-composite girders have poor flexure ratings for all ADTT levels with approximately 50% of the girders having ratings above 1.0 for an ADTT of less than 100. Approximately 80–90% of non- composite girders have satisfactory ratings for shear, depend- ing upon ADTT. Table 22 shows the percentage of girders within each range for the different ADTTs used in the MBE for the FL-04 vehi- cle. At least 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear. Non-composite girders have poor flexure ratings for all ADTT levels with approximately 50% of the girders having ratings above 1.0 for an ADTT of less than 100. Approximately 80–90% of non- composite girders have satisfactory ratings for shear, depend- ing upon ADTT. Table 23 shows the percentage of girders within each range for the different ADTTs used in the MBE for the NC-21 vehi- cle. Approximately 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear. Non-composite girders have poor flexure ratings for all ADTT levels with less than 50% of exterior girders and less than 40% of interior girders having ratings above 1.0 for an ADTT of less than 100. Approximately 80–90% of non-composite girders have satis- factory ratings for shear, depending upon ADTT. Table 24 shows the percentage of girders within each range for the different ADTTs used in the MBE for the NM-04 vehicle. Approximately 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear. Non- composite girders have poor flexure ratings for all ADTT lev- els with less than 60% of exterior girders and 50% of interior girders having ratings above 1.0 for an ADTT of less than 100. Approximately 90% of non-composite girders have satisfac- tory ratings for shear, depending upon ADTT. Table 25 shows the percentage of girders within each range for the different ADTTs used in the MBE for the TX-04 vehi- cle. Approximately 80–90% of composite girders had ratings above 1.0 for all ADTTs for moment and more than 90% have ratings above 1.0 for shear. Non-composite girders have poor flexure ratings for all ADTT levels with less than 50% of exterior girders and less than 40% of interior girders having ratings above 1.0 for an ADTT of less than 100. Approximately 80–90% of non-composite girders have satisfactory ratings for shear, depending upon ADTT. 3.5 Special Permit Vehicles The results for the three vehicles treated as special permits are shown in this section. The live load factors used are those shown in the lower portion of Table 10 unless a service limit state was the controlling rating, in which case the rating does not depend upon the ADTT and a live load factor of 1.0 is used. Table 26 shows the percentage of girders within each range for the different ADTTs used in the MBE for the IL-01 vehicle. At least 90% of composite girders had ratings above 1.0 for all categories for both moment and shear, except for the flexure rating in exterior girders for multiple trip permits with ADTTs of 1,000 and 5,000. Non-composite girders have poor flexure ratings for all ADTT levels with less than 60% of interior gird- ers having ratings above 1.0 when treated as an escorted permit. Exterior non-composite girders have approximately 50% of girders with ratings above 1.0 for flexure. Approximately 80–90% of non-composite girders have satisfactory ratings for shear, depending upon ADTT. Table 27 shows the percentage of girders within each range for the different ADTTs used in the MBE for the OR-06 vehi- cle. Approximately 90% of composite girders had ratings above 1.0 for all ADTTs for both moment and shear with the excep- tion of exterior girders assuming multiple trip permits where 80–85% of girders had ratings above 1.0. Non-composite girders have poor flexure ratings for all ADTT levels with approximately 50–55% of the girders having ratings above 1.0 assuming the vehicle was escorted. Approximately 80–90% of non-composite girders have satisfactory ratings for shear, depending upon permit type. Table 28 shows the percentage of girders within each range for the different permit types used in the MBE for the WA-02 vehicle. Approximately 90% of composite girders had ratings above 1.0 for all permit types for shear. For flexure, a mini- mum of 88% of girders have satisfactory ratings for interior girders and a minimum of 75% of exterior girders have ratings above 1.0. Non-composite girders have poor flexure ratings for all ADTT levels with a minimum of 20% of the girders hav- ing ratings above 1.0 for multiple trip permits with an ADTT greater than 5,000. Between 80% and 90% of non-composite girders have satisfactory ratings for shear, depending upon permit type and ADTT. The number of girders with ratings under 0.5 increases significantly for non-composite girders depending upon the permit type. As an example, for a single- trip escorted permit between 5 and 10% of girders have a rat- ing less than 0.5 while for a multiple trip permit with an ADTT equal to or greater than 5,000 more than 40% of girders have a rating of less than 0.5. 38

39 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT 100 ADTT = 1000 ADTT 5000 ShearMoment DE-07 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) ≤ ≥ ≤ ≥ ≤ ≥ ≤ ≥ ≤ ≥ ≤ ≥ ≤ ≥ ≤ ≥ Table 21. DE-07—LRFR ratings for different ADTT.

40 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment FL-04 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 22. FL-04—LRFR ratings for different ADTT.

41 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 - 0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment NC-21 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 23. NC-21—LRFR ratings for different ADTT.

42 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment NM-04 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 24. NM-04—LRFR ratings for different ADTT.

43 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR ADTT ≤ 100 ADTT = 1000 ADTT ≥ 5000 ShearMoment TX-04 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 25. TX-04—LRFR ratings for different ADTT.

44 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir de rs Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir d er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce nt ag e of G ir d er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir de rs Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 ShearMoment IL-01 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) Table 26. IL-01—LRFR ratings for different ADTT.

45 ShearMoment OR-06 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir de rs Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir d er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce nt ag e of G ir d er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 P er ce n ta ge o f G ir de rs Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9 -1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 Table 27. OR-06—LRFR ratings for different ADTT.

46 ShearMoment WA-02 In te rio r C om po sit e (43 2 g ird ers ) In te rio r N on -C om po sit e (19 3 g ird ers ) Ex te rio r C om po sit e (27 9 g ird ers ) Ex te rio r N on -C om po sit e (13 3 g ird ers ) 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8-0.9 0.7-0.8 0.6 -0.7 0.5-0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8 -0.9 0.7-0.8 0.6 -0.7 0.5- 0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8-0.9 0.7-0.8 0.6 -0.7 0.5-0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8 -0.9 0.7-0.8 0.6 -0.7 0.5-0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8 -0.9 0.7 -0.8 0.6 -0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8 -0.9 0.7 -0.8 0.6-0.7 0.5 -0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8-0.9 0.7-0.8 0.6 -0.7 0.5-0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00% > 1.0 0.9-1.0 0.8 -0.9 0.7-0.8 0.6 -0.7 0.5-0.6 <0.5 Pe rc en ta ge o f G ird er s Rating Factor LFR Single Escorted Single ADTT ≤ 100 Single ADTT = 1000 Single ADTT ≥ 5000 Multiple ADTT ≤ 100 Multiple ADTT = 1000 Multiple ADTT ≥ 5000 Table 28. WA-02—LRFR ratings for different ADTT.

As expected, as the ADTT increases and the associated load factor increases, the number of girders that will pass rating decreases. The permit type and ADTT affect flexural ratings more than they affect shear ratings. Shear is not affected as much because shear resistance is generally larger than the max- imum applied shear and would require a significant increase in load to reduce the rating to a level less than 1.0. Flexure is significantly affected because the cross-section is typically designed for the maximum expected loads and the load factor used in the design is possibly smaller than that used in rating or the rating vehicle is heavier, resulting in ratings less than 1.0. 3.6 Effect of LRFR Rating on Inventory Rating The effect of switching from LFR to LRFR on the allowable truck weight for those girders with LRFR ratings less than 1.0 was investigated. The following graphs provide an indication on how much the weight of the HL-93 design load would have to be reduced for the LRFR rating to be the same as the LFR rating. The weight of the HL-93 load would not neces- sarily need to be reduced by the same percentage to achieve a satisfactory rating (rating factor equals 1.0), as in some cases the LFR rating is significantly larger than the LRFR rating. All graphs shown are for the HL-93 design load and are plotted as general bridge types; the graphs are not divided up between interior and exterior or composite and non-composite. Tables and graphs for the 11 legal and permit vehicles considered are shown for each bridge type in Appendix L. The percentages shown in Tables 29 through 36 are based upon the total number of girders for each superstructure type, not upon the number of girders with ratings less than 1.0. Columns 4 and 5 for moment and Columns 8 and 9 for shear indicate the number of girders with LRFR ratings less than 1.0 and LFR ratings less than 1.0 (Columns 4 and 8) and LFR rat- ings greater than or equal to 1.0 (Columns 5 and 9). Figures 37 through 44 typically show two series; the left series is based upon the number of girders with LRFR ratings less than 1.0. The right series is based upon the number of girders with LFR ratings less than 1.0. The LFR series indicates all girders with LFR ratings less than 1.0, not just those with both LFR and LRFR ratings less than 1.0. 3.6.1 Simple Span Steel Girder Bridges Table 29 and Figure 37 show the distribution of rating fac- tor ratio for girders with LRFR ratings less than 1.0 and also for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and simple span steel girder bridges. Both LFR and LRFR are shown so a comparison can be made as to which method will produce lower ratings. For simple span steel girder bridges, there are 1,037 total girders with 346 girders having LRFR flexure ratings less than 1.0 and 252 girders with LFR flexure ratings less than 1.0. Of the simple span steel girders, 5.7% have LRFR flexure rating factors less than 1.0 yet their LRFR ratings are greater than LFR ratings. Comparatively, 9.8% of the simple span steel gird- ers have LFR flexure ratings less than 1.0, yet their LRFR rating is greater than the LFR rating. For flexure in simple span steel girder bridges, LRFR produces more low ratings than LFR. The number of girders with ratings less than 1.0 increased by 4.9% of the total inventory when switching from LFR to LRFR. 47 LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders % of Total Inventory (1037) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders % of Total Inventory (1037) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 0 0.0% 0 0 9 0.9% 0 9 0.1-0.19 2 0.2% 2 0 42 4.1% 0 42 0.2-0.29 15 1.4% 1 14 25 2.4% 0 25 0.3-0.39 10 1.0% 2 8 17 1.6% 0 17 0.4-0.49 35 3.4% 9 26 7 0.7% 0 7 0.5-0.59 12 1.2% 6 6 8 0.8% 0 8 0.6-0.69 17 1.6% 10 7 5 0.5% 0 5 0.7-0.79 49 4.7% 38 11 4 0.4% 0 4 0.8-0.89 96 9.3% 77 19 0 0.0% 0 0 0.9-0.99 50 4.8% 48 2 0 0.0% 0 0 > 1.00 59 5.7% 59 0 0 0.0% 0 0 Total 346 252 93 117 0 117 Average LRFR/LFR 56.089.0 Table 29. Distribution of rating factor ratios for simple span steel girders with LRFR ratings less than 1.0 for HL-93 design load.

Seventy percent of the girders with LRFR ratings less than 1.0 also have LFR ratings less than 1.0. For shear in simple span steel girders, 117 of 1,037 girders have LRFR shear ratings less than 1.0 and no girders have LFR shear ratings less than 1.0. Ninety-three of the 100 girders with LRFR rating less than 1.0 and ratio of LRFR to LFR rating less than 0.5 are controlled by the rating for the bearing stiffener. The number of girders with ratings less than 1.0 increased by 11.3% of the total inventory when switching from LFR to LRFR. Girders with ratio of LRFR flexure rating to LFR flexure rating less than 0.5 and LRFR ratings less than 1.0 and LFR ratings greater than 1.0 are typically spaced less than 3.5 feet apart. As mentioned earlier, it was determined that close girder spacing is one reason that the LFR and LRFR ratings are sig- nificantly different. The difference in the rating factors is caused by the difference in distribution factor. As the ratio increases, both ratings are less than 1.0 or the LFR rating is greater than 1.0 and the LRFR rating is near 1.0 Girders with ratio of LRFR shear rating to LFR shear rating less than 0.5, with LRFR ratings less than 1.0 are controlled by the bearing stiffener rating. There are 100 girders with an LRFR to LFR ratio less than 0.5; 94 of these are controlled by the bear- ing stiffener rating. The other six girders are controlled by the web shear rating. 3.6.2 Continuous Span Steel Girder Bridges Table 30 and Figure 38 show the distribution of rating fac- tor ratio for girders with LRFR ratings less than 1.0 and also 48 (b)(a) Figure 37. Distribution of rating factor ratio for simple span steel girders with LRFR rating less than 1.0 (a) moment and (b) shear for HL-93 design load. LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders < 1.0 % of Total Inventory (418) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (418) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 0 0.0% 0 0 7 1.7% 0 7 0.1-0.19 0 0.0% 0 0 16 3.8% 0 16 0.2-0.29 2 0.5% 1 1 20 4.8% 0 20 0.3-0.39 6 1.4% 2 4 21 5.0% 2 19 0.4-0.49 11 2.6% 3 8 6 1.4% 2 4 0.5-0.59 10 2.4% 1 9 7 1.7% 5 2 0.6-0.69 20 4.8% 7 13 5 1.2% 1 4 0.7-0.79 33 7.9% 15 18 5 1.2% 2 3 0.8-0.89 25 6.0% 9 16 7 1.7% 3 4 0.9-0.99 23 5.5% 19 4 4 1.0% 4 0 > 1.00 15 3.6% 15 0 2 0.5% 2 0 Total 145 72 73 100 21 79 Average LRFR/LFR 57.029.0 Table 30. Distribution of rating factor ratios for continuous span steel girders with LRFR ratings less than 1.0.

for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and continuous span steel girder bridges. Both LFR and LRFR are shown so a comparison can be made as to which method will produce lower ratings. For continuous span steel girder bridges, there are 418 total girders and 145 girders with a LRFR flexure rating less than 1.0 and 72 girders with a LFR flexure rating less than 1.0. Ninety- six girders, 66% with LRFR ratings less than 1.0, have a LRFR rating that is at least 70% of the LFR rating. The number of girders with ratings less than 1.0 increased by 13.4% of the total inventory when switching from LFR to LRFR. There are 100 girders with a LRFR shear rating less than 1.0 and 21 girders with an LFR shear rating less than 1.0. For shear, 64% of the girders have an LRFR rating less than 1.0 and have an LRFR rating that is less than 40% of the LFR rating. The number of girders with ratings less than 1.0 increased by 16.9% of the total inventory when switching from LFR to LRFR. Girders with LRFR flexure ratings less than 1.0 and with a ratio of ratings less than 0.8 typically have factored LRFR design live loads that are 50% greater than the factored LFR design live loads when the ratings are at the same critical loca- tion. The LRFR resistance is also approximately 90% of the LFR resistance for the same set of girders. Girders with LRFR shear ratings less than 1.0 and a ratio of ratings less than 0.6 are controlled by the bearing stiffener rat- ing for 66 of the 77 girders. The remaining 11 girders are con- trolled by the web shear rating. The LRFR and LFR resistances are generally similar when the critical locations are the same. 3.6.3 Simple Span Prestressed I-Girder Bridges Table 31 and Figure 39 show the distribution of rating factor ratio for girders with LRFR ratings less than 1.0 and also for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and simple span prestressed I-girder bridges. Both LFR and LRFR are shown so a com- parison can be made as to which method will produce lower ratings. For simple span prestressed concrete I-girder bridges, there are 467 total girders; 289 girders have an LRFR flex- ure rating less than 1.0 and 25 girders have an LFR flexure rating less than 1.0. This is an increase of 57% of the total inventory having a rating of less than 1.0. This is due to the requirement to check the stress in the longitudinal steel near the support (AASHTO LRFD Article 5.8.3.5); 215 of the 289 girders with LRFR ratings less than 1.0 are controlled by the longitudinal steel rating. The remaining girders are con- trolled by the stress at the bottom of the beam under ser- vice loads. There are 193 girders with LRFR shear ratings less than 1.0 and 33 girders with LFR shear ratings less than 1.0. Most gird- ers have an LRFR rating in the range of 30–80% of the LFR rating. This is an increase of 32.9% of the total inventory not passing rating when switching from LFR to LRFR. Seventy- five percent of the girders with LRFR shear ratings less than 1.0 for the design vehicle are controlled by the shear friction rating; this is rating of the stress at the interface between the girder and the slab. For flexure, the factored live load moment increased by approximately 40% for the routine permit and legal vehicles, 25% for the design vehicle, and decreased by 10% for the special permit vehicles. The change in live load moment for the legal, routine permit, and special permit vehicles was accompanied by a decrease of approximately 5% in moment resistance. The factored LRFR live load shear increased by 25 to 95% over the factored LFR live load shear. The increase in live load was accompanied by a similar increase in shear resistance. 49 (b)(a) 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% % o f B rid ge In ve nt or y LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (418)) LFR (% of Inventory (418)) 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% % o f B rid ge In ve nt or y LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (418)) LFR (% of Inventory (418)) Figure 38. Distribution of rating factor ratio for continuous span steel girders with LRFR rating less than 1.0 (a) moment and (b) shear.

3.6.4 Simple Span Prestressed Box Girder Bridges Table 32 and Figure 40 show the distribution of rating fac- tor ratio for girders with LRFR ratings less than 1.0 and also for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and simple span prestressed box girder bridges. Both LFR and LRFR are shown so a comparison can be made as to which method will produce lower ratings. For simple span prestressed concrete box-girder bridges, there are 377 total girders with 156 girders having LRFR flex- ure ratings less than 1.0 and 48 girders with LFR flexure ratings less than 1.0. This is an increase of 27.3% of the total inven- tory that will not pass the rating when switching from LFR to LRFR. Fifty-five of the 156 girders with LRFR flexure ratings less than 1.0 are controlled by the longitudinal steel rating. Ninety-eight girders are controlled by the stress at the bottom of beam under service loads. There are 72 girders with LRFR shear ratings less than 1.0 and 15 girders with LFR shear ratings less than 1.0. This is an increase of 13.8% of the total inventory that will not pass the rating when switching from LFR to LRFR. Ten of the 72 gird- ers with LRFR ratings less than 1.0 are controlled by the shear friction rating; this is the stress at the interface between the cast-in-place slab and girder for those with composite decks. The increase in the number of girders with LRFR flexure ratings less than 1.0 is due to increased live loads. For gird- ers with LRFR ratings less than 1.0 and ratio of LRFR rating 50 LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders < 1.0 % of Total Inventory (467) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (467) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 2 0.4% 0 2 1 0.2% 1 0 0.1-0.19 2 0.4% 0 2 7 1.5% 0 7 0.2-0.29 8 1.7% 2 6 8 1.7% 0 8 0.3-0.39 33 7.1% 4 29 24 5.1% 0 24 0.4-0.49 53 11.4% 1 52 29 6.2% 2 27 0.5-0.59 54 11.6% 2 52 39 8.4% 4 35 0.6-0.69 81 17.3% 6 75 34 7.3% 9 25 0.7-0.79 42 9.0% 7 35 34 7.3% 9 25 0.8-0.89 12 2.6% 2 10 13 2.8% 5 8 0.9-0.99 1 0.2% 0 1 2 0.4% 1 1 > 1.00 1 0.2% 1 0 2 0.4% 2 0 Total 289 25 264 193 33 160 Average LRFR/LFR 87.026.0 Table 31. Distribution of rating factor ratio for simple span prestressed concrete I-girders with LRFR rating less than 1.0. (b)(a) 0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00% 14.00% 16.00% 18.00% 20.00% % o f I n ve n to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (467)) LFR (% of Inventory (467)) 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% 7.00% 8.00% 9.00% % o f I n v e n to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (467)) LFR (% of Inventory (467)) Figure 39. Distribution of rating factor ratio for simple span prestressed concrete I-Girders with LRFR rating less than 1.0 (a) moment and (b) shear.

to LFR rating less than 0.8, the factored LRFR live loads are approximately 50% higher than the factored LFR live loads. The flexural resistance increased by approximately 10%. There are a large number of girders with LRFR shear ratings less than 1.0 for the design load, but for most other vehicles there are very few. 3.6.5 Simple Span Reinforced Concrete T-Beam Bridges Table 33 and Figure 41 show the distribution of rating factor ratio for girders with LRFR ratings less than 1.0 and for LFR rat- ings less than 1.0 in tabular and graphical format for the design vehicle and simple span reinforced concrete T-beam bridges. Both LFR and LRFR are shown such that a comparison can be made as to which method will produce lower ratings. For simple span reinforced concrete T-beam bridges, there are 295 total girders with 269 girders having LRFR flexure rat- ings less than 1.0 and 131 girders having LFR flexure ratings less than 1.0. This is an increase of 46.8% of the total inven- tory not passing rating when switching from LFR to LRFR. Two hundred fifty-eight of the 269 girders with LRFR flexure ratings less than 1.0 are controlled by the stress in the longi- tudinal steel near the ends of the girders. Most girders have LRFR ratings that are between 50 and 90% of the LFR rating. There are 194 girders with LRFR shear ratings less than 1.0 and 148 girders with LFR shear ratings less than 1.0. This is an increase of 8.4% of the total inventory not passing rating 51 LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders <1.0 % of Total Inventory (377) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (377) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 3 0.8% 0 3 2 0.5% 1 1 0.1-0.19 2 0.5% 2 0 1 0.3% 0 1 0.2-0.29 4 1.1% 1 3 8 2.1% 0 8 0.3-0.39 9 2.4% 0 9 10 2.7% 1 9 0.4-0.49 13 3.4% 2 11 16 4.2% 0 16 0.5-0.59 36 9.5% 7 29 13 3.4% 5 8 0.6-0.69 29 7.7% 5 24 8 2.1% 1 7 0.7-0.79 21 5.6% 4 17 9 2.4% 4 5 0.8-0.89 19 5.0% 8 11 3 0.8% 1 2 0.9-0.99 12 3.2% 11 1 2 0.5% 2 0 > 1.00 8 0.8% 8 0 0 0.0% 0 0 Total 156 48 108 72 15 57 Average LRFR/LFR 39.067.0 Table 32. Distribution of rating factor ratio for simple span prestressed concrete box girders with LRFR rating less than 1.0. (b)(a) 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% % o f I n v e n to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (377)) LFR (% of Inventory (377)) 0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5% 4.0% 4.5% % o f I n v e n to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (377)) LFR (% of Inventory (377)) Figure 40. Distribution of rating factor ratio for simple span prestressed concrete box girders with LRFR rating less than 1.0 (a) moment and (b) shear for HL-93.

when switching from LFR to LRFR. Most girders have a ratio of LRFR rating to LFR rating greater than 40%. 3.6.6 Simple Span Reinforced Concrete Slab Bridges Table 34 and Figure 42 show the distribution of rating fac- tor ratio for girders with LRFR ratings less than 1.0 and also for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and simple span reinforced concrete slab bridges. Both LFR and LRFR are shown so a comparison can be made as to which method will produce lower ratings. For simple span reinforced concrete slab bridges, there are 99 total bridges with 64 bridges having LRFR flexure ratings less than 1.0 and 27 bridges with LFR flexure ratings less than 1.0. This is an increase of 37% of total inventory that will not pass the rating when switching from LFR to LRFR. Sixty of the 64 bridges with LRFR ratings less than 1.0 are controlled by the stress in the longitudinal steel near the end of the gird- ers; the remaining four are controlled by the strength limit state. Most bridges with LRFR ratings less than 1.0 have LRFR ratings in the range of 50–70% of the LFR rating. There are five bridges with LRFR shear ratings less than 1.0 and no bridges with LFR shear ratings less than 1.0. This is an increase of 3% of total inventory that will not pass the rating when switching from LFR to LRFR. This also shows that for reinforced concrete slab bridges, checking shear is most likely not necessary. 52 Table 33. Distribution of rating factor ratio for simple span reinforced concrete T-beams with LRFR rating less than 1.0. LRFR/LFR Range raehStnemoM RFLRFRLRFLRFRL No. of Girders < 1.0 % of Total Inventory (295) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (295) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 2 0.7% 1 1 3 0.5% 3 0 0.1-0.19 5 1.7% 1 4 2 0.3% 1 1 0.2-0.29 11 3.7% 2 9 2 2.1% 1 1 0.3-0.39 10 3.4% 3 7 11 2.7% 4 7 0.4-0.49 10 3.4% 2 8 18 4.2% 11 7 0.5-0.59 51 17.3% 17 34 24 3.4% 20 4 0.6-0.69 75 25.4% 36 39 32 2.1% 26 6 0.7-0.79 70 23.7% 40 30 25 2.4% 14 11 0.8-0.89 29 9.8% 23 6 22 0.8% 15 7 0.9-0.99 5 1.7% 5 0 21 0.5% 19 2 > 1.00 1 0.3% 1 0 34 0.0% 34 0 Total 269 131 138 194 148 46 Average LRFR/LFR 38.046.0 (b)(a) 0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% % o f I nv en to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (295)) LFR (% of Inventory (295)) 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% 18.0% 20.0% % o f I nv en to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (295)) LFR (% of Inventory (295)) Figure 41. Distribution of rating factor ratio for simple span reinforced concrete T-beams with LRFR rating less than 1.0 (a) moment and (b) shear.

3.6.7 Continuous Span Reinforced Concrete Slab Bridges Table 35 and Figure 43 show the distribution of rating fac- tor ratio for girders with LRFR ratings less than 1.0 and also for LFR ratings less than 1.0 in tabular and graphical format for the design vehicle and continuous reinforced concrete slab bridges. Both LFR and LRFR are shown so a comparison can be made as to which method will produce lower ratings. For continuous span reinforced concrete slab bridges, there are 105 total bridges with 96 bridges having LRFR flexure rat- ings less than 1.0 and 66 bridges with LFR flexure ratings less than 1.0. This is an increase of 28.6% of the continuous RC slab bridge inventory. Ninety-five of the 96 slabs with LRFR ratings less than 1.0 are controlled by the stress in the longitu- dinal steel near the end of the span. Most bridges have a LRFR flexure rating in the range of 50–80% of the LFR rating. There are 74 bridges with LRFR shear ratings less than 1.0 and 41 bridges with LFR shear rating less than 1.0. This is an increase of 29.5% of the continuous RC slab bridge inventory. Most bridges have a LRFR rating in the range of 50–80% of the LFR rating. 3.6.8 Continuous Prestressed Concrete I-Girder Bridges Table 36 and Figure 44 show the distribution of rat- ing factor ratio for girders with LRFR ratings less than 1.0 53 Table 34. Distribution of rating factor ratio for simple span reinforced concrete slabs with LRFR rating less than 1.0. LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders < 1.0 % of Total Inventory (99) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (99) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 2 2.0% 1 1 0 0.0% 0 0 0.1-0.19 1 1.0% 0 1 0 0.0% 0 0 0.2-0.29 0 0.0% 0 0 0 0.0% 0 0 0.3-0.39 2 2.0% 0 2 2 2.0% 0 2 0.4-0.49 4 4.0% 0 4 0 0.0% 0 0 0.5-0.59 3 3.0% 1 2 3 3.0% 0 3 0.6-0.69 15 15.2% 3 12 0 0.0% 0 0 0.7-0.79 24 24.2% 14 10 0 0.0% 0 0 0.8-0.89 8 8.1% 3 5 0 0.0% 0 0 0.9-0.99 5 5.1% 5 0 0 0.0% 0 0 > 1.00 0 0.0% 0 0 0 0.0% 0 0 Total 64 27 37 5 0 5 Average LRFR/LFR 72.137.0 (b)(a) 0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% % o f I n v e n to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (99)) LFR (% of Inventory (99)) 0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5% % o f I n v e n to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (99)) LFR (% of Inventory (99)) Figure 42. Distribution of rating factor ratio for simple span reinforced concrete slabs with LRFR rating less than 1.0 (a) moment and (b) shear.

and also for LFR ratings less than 1.0 in tabular and graphi- cal format for the design vehicle and simple span steel I-girder bridges. Both LFR and LRFR are shown so a com- parison can be made as to which method will produce lower ratings. For continuous, prestressed concrete I-girder bridges, there are 238 total girders with 226 girders having LRFR flexure rat- ings less than 1.0 and 19 girders with LFR flexure ratings less than 1.0. This is an increase of 86.9% of the continuous pre- stressed concrete girders inventory that will have ratings less than 1.0 when switching from LFR to LRFR. Two hundred twenty-five of the 226 girders with LRFR ratings of less than 1.0 are controlled by the stress in the longitudinal steel near the end of the girders. The LRFR ratings are generally less than 80% of the LFR rating. There are 113 girders with LRFR shear ratings less than 1.0 and 31 girders with LFR shear ratings less than 1.0. This is an increase of 32.4% of the number of prestressed concrete gird- ers inventory that will have insufficient ratings when switch- ing from LFR to LRFR. Most girders have LRFR ratings that are 30–90% of the LFR rating. Ninety of the 113 girders with LRFR shear ratings of less than 1.0 are controlled by the rat- ing of the stress at the interface between the girder and the composite deck. 54 Table 35. Distribution of rating factor ratio for continuous span reinforced concrete slabs with LRFR rating less than 1.0. LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders < 1.0 % of Total Inventory (105) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (105) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 6 5.7% 6 0 0 0.0% 0 0 0.1-0.19 0 0.0% 0 0 0 0.0% 0 0 0.2-0.29 0 0.0% 0 0 4 3.8% 0 4 0.3-0.39 1 1.0% 1 0 0 0.0% 0 0 0.4-0.49 2 1.9% 2 0 2 1.9% 1 1 0.5-0.59 23 21.9% 15 8 7 6.7% 3 4 0.6-0.69 36 34.3% 28 8 16 15.2% 7 9 0.7-0.79 23 21.9% 10 13 19 18.1% 9 10 0.8-0.89 5 4.8% 4 1 15 14.3% 11 4 0.9-0.99 0 0.0% 0 0 8 7.6% 7 1 > 1.00 0 0.0% 0 0 3 2.9% 3 0 Total 96 66 30 74 41 33 Average LRFR/LFR 97.026.0 (b)(a) 0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% 35.0% 40.0% % o f I nv en to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (105)) LFR (% of Inventory (105)) 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% 18.0% 20.0% % o f I nv en to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (105)) LFR (% of Inventory (105)) Figure 43. Distribution of rating factor ratio for continuous span reinforced concrete slabs with LRFR rating less than 1.0 (a) moment and (b) shear.

3.7 Comparison of Reliability Index to Live Load Factors The determination of the reliability index corresponding to the live load factor needed to make the factored loads equal to the factored resistance provided insight into what level of reliability the current load factors are providing. For each vehicle, a scatter plot is created comparing the reliability index to the required live load factor for an ADTT = 1,000. The fig- ures show the results for all types of structures used in this project. The following graphs also provide an indication into the number of girders that will have a rating less than 1.0 when the value of a certain load factor is changed. All points to the right of a specific load factor will have a rating greater than 1.0 when this load factor is specified. Each point in the following figures was determined using the following process: 1. The factored dead and live load force effects and factored resistance were determined using NCHRP Process 12-50 output. 2. The load factor for live load that will make the girder have a rating of 1.0 was determined. 3. The section reliability index was determined. 4. The graph was plotted using the values of the load factor and reliability index for each girder. 55 LRFR/LFR Range raehStnemoM LRFR LFR LRFR LFR No. of Girders < 1.0 % of Total Inventory (238) No. of Girders < 1.0 No. of Girders > 1.0 No. of Girders < 1.0 % of Total Inventory (238) No. of Girders < 1.0 No. of Girders > 1.0 0.0-0.09 34 14.3% 5 29 0 0.0% 0 0 0.1-0.19 14 5.9% 3 11 0 0.0% 0 0 0.2-0.29 24 10.1% 0 24 13 5.5% 0 13 0.3-0.39 27 11.3% 4 23 33 13.9% 12 21 0.4-0.49 37 15.5% 1 36 10 4.2% 2 8 0.5-0.59 41 17.2% 2 39 8 3.4% 0 8 0.6-0.69 29 12.2% 2 27 16 6.7% 3 13 0.7-0.79 18 7.6% 1 17 11 4.6% 3 8 0.8-0.89 2 0.8% 1 1 13 5.5% 3 10 0.9-0.99 0 0.0% 0 0 4 1.7% 3 1 > 1.00 0 0.0% 0 0 5 2.1% 5 0 Total 226 19 207 113 31 82 Average LRFR/LFR 18.024.0 Table 36. Distribution of rating factor ratio for continuous span prestressed concrete I-girders with LRFR rating less than 1.0. (b)(a) 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% 18.0% 20.0% % o f I nv e n to ry LRFR/LFR Flexure Rating Ratio LRFR (% of Inventory (238)) LFR (% of Inventory (238)) 0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0% 14.0% 16.0% % o f I n v e n to ry LRFR/LFR Shear Rating Ratio LRFR (% of Inventory (238)) LFR (% of Inventory (238)) Figure 44. Distribution of rating factor ratio for continuous span prestressed concrete I-girders with LRFR rating less than 1.0 (a) moment and (b) shear.

5. For any girder, specifying a load factor equal to or less than the one calculated for this girder (Step 2) will mean that the girder will have a rating factor greater than or equal to 1.0. 3.7.1 Design Vehicle For the HL-93 Design Load, the graphs show that a live load factor of 1.75 provides the “Inventory” or “Design” level of reliability corresponding to a reliability index of 3.5. For flexure, most types of bridges follow the same trend; the exception is the precast, prestressed box beam bridges. The prestressed box beams tend to have higher levels of reli- ability for low live load factors than for other types. In the graph depicting the level of reliability for shear, depending on the type of girder, the steel bridges tend to be either above or below the concrete bridges. The rolled shapes (and built-up shapes, since they were assumed to have the same sta- tistical parameters for shear) have higher reliability because there is less variation in the web section, thus reducing the number of locations where the section is highly utilized in shear, while plate girders have more variation as shown in Figure 45. 3.7.2 Routine Permit Vehicles From the MBE, it was determined that routine permit vehicles are to have the same level of reliability as the tradi- tional AASHTO Operating rating. This level corresponds to a reliability index of 2.5. In the following figures, an approx- imate load factor is selected by following the assumed relia- bility index horizontally to the intersection with the data points. These values may be used to modify the load factors present in the upper portion of Table 6A.4.5.4.2a-1 in the MBE. The proposed load factors are indicated by solid lines; the current load factors and associated reliability index are indicated by a dashed line. Table 37 shows the target reliabil- ity index assumed in the development of the MBE in the third column and the current live load factor for an ADTT of 1,000 in the fourth column. Using Figure 46 through Figure 50, the reliability index corresponding to the current live load factor of 1.6 is estimated and shown in the fifth column. The sixth column shows the live load factor estimated from Fig- ure 46 through Figure 50 to correspond to the target reliabil- ity index of 2.5. The proposed live load factors shown in Table 37 are for an ADTT = 1,000. The current MBE assumes that multiple lanes are loaded for routine permit vehicles; the calculated live load factors assume that multiple lanes are loaded. Multiple lanes loaded implies that other traffic exists on the bridge, therefore the proposed live load factors can be used in direct compari- son with those currently in the MBE. 3.7.3 Special or Limited Crossing Permit Vehicles From the MBE, it was determined that special or limited crossing permit vehicles, with the exception of the single-trip permit with an escort, are to have the same level of reliability as the design load, the traditional AASHTO Inventory rating. This level corresponds to a reliability index of 3.5. In the fol- lowing graphs, a load factor is selected by following the relia- bility index needed horizontally to the intersection with the data points. These values may be used to modify the load fac- tors present in the lower portion of Table 6A.4.5.4.2a-1 in the MBE. The proposed load factors are indicated by solid lines; the current load factors and associated reliability index are indicated by a dashed line. Figures 51 to 53 also show the load factor needed to obtain the operating level (reliability index of 2.5) of reliability. Table 38 shows the reliability index corresponding to the current live load factor of 1.4. For two vehicles, it was deter- mined that the current live load factor does not provide the target reliability level of 3.5 for moment. To obtain a target reliability of 3.5 for all vehicles, a live load factor of at least 1.45 should be used. If the target reliability was reduced to the AASHTO Operating level, i.e., a reliability index of 2.5, the proposed live load factor would be 1.10. The rating for special permit vehicles is based upon a single lane loaded and the load factor accounts for the traffic in the second lane. As the calcu- lated live load factors assume no other heavy vehicles signifi- cantly contribute to the maximum load effect when the permit vehicle is also positioned to produce maximum load, it is pro- posed that the values shown in Table 38 be used for ADTT = 100. The live load factors for ADTT = 1,000 and ADTT ≥ 5,000 are determined by increasing the live load factor for ADTT ≤ 100 by the same amount as currently shown in the MBE. This would result in proposed live load factors of 1.5 for a reliability index of 3.5 and 1.15 for a reliability index of 2.5 for ADTT = 1,000. 3.7.4 AASHTO Legal Vehicles From the MBE, it was determined that legal vehicles are to have the same level of reliability as associated with the tradi- tional AASHTO Operating rating. This level corresponds to a reliability index of 2.5. In the following figures, an approx- imate load factor is selected by following the target reliability index horizontally to the intersection with the data points. These values may be used to modify the load factors present in Table 6A.4.4.2.3a-1 in the MBE. The proposed load factors are indicated by solid lines; the current load factors and asso- ciated reliability index are indicated by a dashed line. The fol- lowing figures also show the load factor needed to obtain the operating level of reliability. 56

57 (a) (b) -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 45. Reliability index versus live load factor for HL-93 vehicle (a) moment and (b) shear.

Truck Force Effect Target β in MBE γL in MBE (ADTT = 1,000) β corresponding to current γL γL corresponding to target β Figure DE-07 Moment 2.5 1.6 3.6 1.15 Figure (a) )b(erugiF51.15.3raehS FL-04 )a(erugiF51.15.3tnemoM )b(erugiF51.15.3raehS NC-21 )a(erugiF51.16.3tnemoM )b(erugiF51.152.3raehS NM-04 )a(erugiF51.14.3tnemoM )b(erugiF52.13.3raehS TX-04 )a(erugiF51.16.3tnemoM )b(erugiF51.15.3raehS Table 37. Proposed live load factors for routine permit vehicles. 58 Table 39 shows the reliability index corresponding to the current live load factor for the AASHTO legal trucks when an ADTT of 1,000 is assumed. The reliability index correspon- ding to a live load factor of 1.65 is at least 3.5, while the target reliability is 2.5. Considering the target reliability and using Figures 54 through 56, the live load factor can be reduced to approximately 1.3. 3.7.5 Proposed Live Load Factors To be adequate for all types of structures, the proposed live load factors must encompass the largest values needed for moment and shear. The required values for each vehicle included in the study are presented in Table 40. As the load factors listed for “special and limited crossing permits” in Table 35 are based on analysis utilizing the single lane distri- bution factors with no other vehicles on the structure, the val- ues for the “special or limited crossing permits” shown in Table 37 have been increased by 0.05 from those shown in Table 38 to account for the possibility of other vehicles being present and contributing to the maximum load effect (the same increase in live load factor between ADTT = 100 and ADTT = 1,000 currently in the MBE). The table indicates the live load factor for routine permits has been decreased from 1.60 to 1.25 and for the AASHTO legal vehicles from 1.65 to 1.30. The live load factor for the special permit vehicles may increase, if the target reliability index remains at 3.5, from 1.4 to 1.5 or it may decrease, if the target reliability index is reduced to 2.5, from 1.4 to 1.15. It is proposed that for an ADTT = 1,000 that the following live load factors be used: • Routine Permit vehicles = 1.25, • Special Single trip allowed to mix with other vehicles = 1.5 for β = 3.5 or 1.15 for β = 2.5 • AASHTO Legal Vehicles = 1.30 As indicated earlier, using a reliability index of 3.5 for single and limited crossing permit vehicles was intended to ensure that the LRFR will not allow permit vehicles significantly heav- ier than those allowed under LFR. The analysis of the large bridge sample used in this research indicates that ensuring a reliability index of 3.5 for the trucks included in this study will require a higher load factor than currently shown in the MBE. This would result in more bridges not passing the rating under LRFR and was thought to be too restrictive. In consul- tation with the project panel, it was decided that a reliability index of 2.5, which is used for legal vehicles and routine per- mit vehicles, should be used for single and limited crossing permit vehicles. Only results associated with the load factors determined assuming a target reliability index of 2.5 are shown in the following sections. 3.8 Selection of Load Factors for Implementation in the MBE For any particular load factor, the highest value among those determined for different types of structures should be selected. The controlling values are listed in Tables 41 through 43. Tables 38, 39, and 40 are similar to Table 6A.4.4.2.3a-1, Table 6A.4.4.2.3b-1, and Table 6A.4.5.4.2a-1 of the MBE, respectively. In some cases, this research did not specifically develop a value for the load factor. In such cases, engineering judg- ment is used to develop the proposed values. For example, when the value determined in this research is thought to correspond to a certain ADTT, the values corresponding to other ADTTs are determined to have the same difference between the values as in the current MBE. In case of the specialized hauling vehicles, the values were selected such that they are not higher than those determined for the rou- tine commercial traffic. The values shown with strikethrough in Tables 41 through 43 represent the values in the current MBE. • In Table 42 and Table 43: No analyses were conducted under NCHRP Project 12-78 to support the values shown

59 (a) (b) -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.000.00 1.00 2.00 3.00 4.00 5.00 R el ia bi lit y In de x,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.000.00 1.00 2.00 3.00 4.00 5.00 R el ia bi lit y In de x,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 46. Reliability index versus live load factor for DE-07 vehicle (a) moment and (b) shear.

60 (a) (b) -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 47. Reliability index versus live load factor for FL-04 vehicle (a) moment and (b) shear.

61 (a) (b) -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 48. Reliability index versus live load factor for NC-21 vehicle (a) moment and (b) shear.

62 (a) (b) -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 49. Reliability index versus live load factor for NM-04 vehicle (a) moment and (b) shear.

63 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 50. Reliability index versus live load factor for TX-04 vehicle (a) moment and (b) shear.

64 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 - 2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 51. Reliability index versus live load factor for IL-01 vehicle (a) moment and (b) shear.

65 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 52. Reliability index versus live load factor for OR-06 vehicle (a) moment and (b) shear.

66 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 53. Reliability index versus live load factor for WA-02 vehicle (a) moment and (b) shear.

in bold/italic typeface. The shown values were rationally determined considering the currently existing values in the MBE and the difference between the existing and proposed load factors for the same ADTT where analyses were con- ducted to support the proposed values. • In Table 43: Values listed in the current MBE for Special or Limited Crossing (single or multiple trips mixed with other traffic) are based on a target reliability index of 3.5. Values listed in Table 43 for these permits are based on a target reliability index of 2.5. The process of determining reliability indices and the asso- ciated load factors involves several sources of approxima- tions. As shown, some of the load factors determined based on the analyses appear to be lower than what the engineering community is accustomed to. It is recommended that these low factors be increased to account for the approximations in the analyses. The following minimum values are recom- mended for the lowest ADTT category (<100) based on engi- neering judgment and the minimum values accepted in the past: • For Generalized Live Load Factors, γL for Routine Commercial Traffic: 1.20 • Generalized Live Load Factors, γL for Specialized Hauling Vehicles: 1.15 • For routine and annual permits: ▪ For vehicles up to 100 kips gross weight 1.15 ▪ For vehicles > 150 kips gross weight (no revision) 1.10 • For Single-Trip Escorted permit (no revision): 1.15 • For Single-Trip mixed with traffic permit: 1.20 When these recommended values are incorporated and val- ues for other ADTTs are adjusted to maintain the difference between the calculated values for different ADTTs and the adjusted values for the different ADTTs, Tables 44 through 46 are developed. 67 Truck Force Effect Target β in MBE γL in MBE β corresponding to current γL γL corresponding to target β % of girders with β less than βTarget Figure IL-01 Moment 3.5 ADTT = 100: 1.35 ADTT = 1,000: 1.4 3.35 Figure (a) (β = 3.5) 1.45 8.40% (β = 2.5) 1.05 4.58% Shear 3.5 Figure (b) (β = 3.5) 1.40 3.49% (β = 2.5) 1.10 1.98% OR- 06 Moment 3.3 Figure (a) (β = 3.5) 1.45 8.80% (β = 2.5) 1.00 5.27% Shear 3.5 Figure (b) (β = 3.5) 1.40 3.26% (β = 2.5) 1.10 1.68% WA- 02 Moment 3.8 Figure (a) (β = 3.5) 1.30 12.85% (β = 2.5) 1.00 8.90% Shear 3.5 Figure (b) (β = 3.5) 1.40 8.21% (β = 2.5) 1.05 4.35% Table 38. Proposed live load factors for special permit vehicles. Truck Force Effect Target β in MBE γL in MBE (ADTT = 1,000) β corresponding to current γL γL corresponding to target β Figure AASHTO Type 3 Moment 2.5 1.65 3.5 1.15 Figure (a) )b(erugiF03.17.3raehS AASHTO Type 3-3 )a(erugiF51.15.3tnemoM )b(erugiF01.15.3raehS AASHTO Type 3S2 )a(erugiF01.17.3tnemoM )b(erugiF01.15.3raehS Table 39. Proposed live load factors for AASHTO legal trucks.

68 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 54. Reliability index versus live load factor for Type 3 vehicle (a) moment and (b) shear.

69 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 55. Reliability index versus live load factor for Type 3-3 vehicle (a) moment and (b) shear.

70 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 -2.00 0.00 2.00 4.00 6.00 8.00 10.00 -1.00 0.00 1 (a) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I (b) .00 2.00 3.00 4.00 5.00 R e lia bi lit y In de x ,  LRFR Live Load Factor Simple Span Steel Simple Span PS I Simple Span PS Box Simple Span RC T-Beam Simple Span RC Slab Continuous Steel Continuous RC Slabs Continuous PS I Figure 56. Reliability index versus live load factor for Type 3S2 vehicle (a) moment and (b) shear.

71 Vehicle Moment Shear Critical Routine Permit Vehicles DE-07 β = 2.5 1.15 1.15 1.15 FL-04 β = 2.5 1.15 1.15 1.15 NC-21 β = 2.5 1.15 1.15 1.15 NM-04 β = 2.5 1.15 1.25 1.25 TX-04 β = 2.5 1.15 1.15 1.15 Special or Limited Crossing Permits IL-01 β = 2.5 1.10 1.15 1.15 β = 3.5 1.50 1.45 1.50 OR-06 β = 2.5 1.05 1.15 1.10 β = 3.5 1.50 1.45 1.50 WA-02 β = 2.5 1.05 1.10 1.10 β = 3.5 1.35 1.45 1.45 Legal Loads Type 3 β = 2.5 1.15 1.30 1.30 Type 3S2 1.10 1.10 1.10 Type 3-3 1.15 1.10 1.15 Table 40. Proposed live load factors for ADTT = 1,000. Traffic Volume (one direction) Load Factor Unknown 1.80 1.45 ADTT ≥ 5000 1.80 1.45 ADTT = 1000 1.65 1.30 ADTT ≤ 100 1.40 1.05 Table 41. Calculated generalized live load factors, L for routine commercial traffic. ≥ ≤ Traffic Volume (one direction) Load Factor Unknown 1.60 1.45 ADTT 5000 1.60 1.45 ADTT = 1000 1.40 1.30 ADTT 100 1.15 1.05 Table 42. Calculated generalized live load factors, L for specialized hauling vehicles. Permit Type Frequency Loading Condition DF ADTT (one direction) Load Factor by Permit Weight Up to 100 kips > 150 kips Routine or Annual Unlimited Crossings Mix with traffic (other vehicles may be on the bridge) Two or more lanes >5000 1.80 1.45 1.30 =1000 1.60 1.25 1.20 <100 1.40 1.05 1.10 sthgieWllA Special or Limited Crossing Single-Trip Escorted with no other vehicles on the bridge One lane N/A 1.15 Single-Trip Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.50 1.25 =1000 1.40 1.15 <100 1.35 1.10 Multiple- Trips (less than 100 crossings) Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.85 1.60 =1000 1.75 1.50 <100 1.55 1.45 Table 43. Calculated permit load factors, L. Due to the generally small differences between the load fac- tors for ADTT less than 100 and those for ADTT = 1000 and due to the difficulty in enforcing the routes used by permit and commercial vehicles, it is recommended that the values corresponding to ADTT less than 100 be removed from the load factor tables. Tables 47 through 49 are the same as Table 44 through Table 46, respectively, with the rows corresponding to ADTT less than 100 removed. In addition, for the routine or annual permits, the distinction between vehicles up to 100 kips and vehicles above 150 kips was also eliminated. This distinc- tion resulted in difficulty in determining the load factors as the current MBE required that only the axles on the bridge be used in determining the category (up to 100 kips or above 150 kips). For a truck moving across a short bridge the load factor varied as the weight of the axles on the bridge changed. 3.9 Effect of Using Proposed Live Load Factors on Rating Factors The effect of changing the LRFR live load factors to the proposed values is shown in the following tables for each type of bridge that was used in this study. The proposed load fac- tors used in this section are 1.3 for the AASHTO Legal Vehi- cles, 1.25 for routine permit vehicles, and 1.25 for the special permit vehicles for a reliability index of 2.5. The first eight columns of each table are the same and are described below: Column 1—Bridge Type Column 2—Total number of girders from this bridge type

Column 3—Vehicle type (design, legal, routine permit, spe- cial permit) Column 4—Vehicle Name Column 5—Load Effect (Moment/Shear) Column 6—Number of girders with LFR ratings less than 1.0, inventory ratings for design vehicle, operating ratings for all others Column 7—Number of girders with LRFR ratings less than 1.0 assuming that no criteria are ignored in the LRFR rating. Column 8—Percent increase in number of girders not pass- ing rating as a percentage of the total number of girders, calculated using the following formula: The remaining columns will be described for each table below. 3.9.1 Simple Span Steel Table 50 shows the effect of changing the load factors to those proposed earlier for the 1037 simple span steel girders included % . . change LRFR LFR Total = < − < × 1 0 1 0 100 72 Traffic Volume (one direction) Load Factor Unknown 1.80 1.45 ADTT ≥ 5000 1.80 1.45 ADTT = 1000 1.65 1.30 ADTT ≤ 100 1.40 1.20 Table 44. Calculated generalized live load factors, L for routine commercial traffic. ≥ ≤ Traffic Volume (one direction) Load Factor Unknown 1.60 1.45 ADTT 5000 1.60 1.45 ADTT = 1000 1.40 1.30 ADTT 100 1.15 1.15 Table 45. Calculated generalized live load factors, L for specialized hauling vehicles. Permit Type Frequency Loading Condition DF ADTT (one direction) Load Factor by Permit Weight Up to 100 kips > 150 kips Routine or Annual Unlimited Crossings Mix with traffic (other vehicles may be on the bridge) Two or more lanes >5000 1.80 1.45 1.30 =1000 1.60 1.25 1.20 <100 1.40 1.15 1.10 sthgieWllA Special or Limited Crossing Single-Trip Escorted with no other vehicles on the bridge One lane N/A 1.15 Single-Trip Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.50 1.35 =1000 1.40 1.25 <100 1.35 1.20 Multiple- Trips (less than 100 crossings) Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.85 1.60 =1000 1.75 1.50 <100 1.55 1.45 Table 46. Calculated permit load factors, L. Traffic Volume (one direction) Load Factor Unknown 1.80 1.45 ADTT ≥ 5000 1.80 1.45 ADTT = 1000 1.65 1.30 Table 47. Calculated generalized live load factors, L for routine commercial traffic. Traffic Volume (one direction) Load Factor Unknown 1.60 1.45 ADTT ≥ 5000 1.60 1.45 ADTT = 1000 1.40 1.30 Table 48. Calculated generalized live load factors, L for specialized hauling vehicles.

73 Permit Type Frequency Loading Condition DF ADTT (one direction) Load Factor Routine or Annual Unlimited Crossings Mix with traffic (other vehicles may be on the bridge) Two or more lanes >5000 1.80 1.45 =1000 1.60 1.25 Special or Limited Crossing Single-Trip Escorted with no other vehicles on the bridge One lane N/A 1.15 Single-Trip Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.50 1.35 =1000 1.40 1.25 Multiple- Trips (less than 100 crossings) Mix with traffic (other vehicles may be on the bridge) One lane >5000 1.85 1.60 =1000 1.75 1.50 Table 49. Calculated permit load factors, L. Total % Change Ignoring 80007 % Change (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Moment 295 346 4.92% n/a n/a n/a Shear 0 117 11.28% 21 2.03% n/a n/a n/a Moment 72 211 13.40% 151 72 7.62% Shear 0 41 3.95% 0 0.00% 24 0 2.31% Moment 37 175 13.31% 110 37 7.04% Shear 0 41 3.95% 2 0.19% 27 0 2.60% Moment 65 195 12.54% 142 65 7.43% Shear 0 45 4.34% 1 0.10% 18 0 1.74% Moment 100 240 13.50% 146 100 4.44% Shear 0 52 5.01% 3 0.29% 33 0 3.18% Moment 97 235 13.31% 149 97 5.01% Shear 0 48 4.63% 2 0.19% 30 0 2.89% Moment 130 273 13.79% 202 130 6.94% Shear 0 49 4.73% 2 0.19% 30 0 2.89% Moment 80 209 12.44% 126 80 4.44% Shear 0 39 3.76% 0 0.00% 21 0 2.03% Moment 153 296 13.79% 229 153 7.33% Shear 0 66 6.36% 3 0.29% 45 0 4.34% Moment 180 217 3.57% 186 180 0.58% Shear 0 54 5.21% 3 0.29% 43 0 4.15% Moment 201 210 0.87% 186 201 -1.45% Shear 0 48 4.63% 4 0.39% 34 0 3.28% Moment 231 276 4.34% 228 231 -0.29% Shear 1 87 8.29% 8 0.68% 66 1 6.27% Using Existing Load Factors IL-01 OR-06 % Change # of girders w/ LFR < 1.0 # of girders w/ LRFR < 1.0 EffectVehicle Vehicle Type Using Proposed Load Factors HL-93 # of girders w/ LRFR < 1.0 Design # of girders w/ LFR < 1.0 Legal Routine Permit Special Permit NM -04 Si m pl e Sp an S te el 1037 # of Girders Type TX-04 WA -02 AASHTO Type 3 AASHTO Type 3 -3 AASHTO Type 3S2 DE-07 FL-04 NC-21 Table 50. Simple span steel—effect of proposed load factors.

in the study. Column 9 shows the number of girders with shear ratings less than 1.0 when the bearing stiffener rating is ignored. Column 10 shows the percent change in girders with shear rat- ings less than 1.0 when the bearing stiffener rating (80007) is ignored. Column 11 is the number of girders with LRFR ratings less than 1.0 using the proposed live load factors, while column 12 is the number of girders with LFR ratings less than 1.0 (same as column 6). Column 13 shows the percent change between the number of girders with ratings less than 1.0 for LRFR using the proposed live load factors and LFR. The increase in number of girders with LRFR flexure ratings less than 1.0 is mostly due to an increase in live load and a decrease of approximately 5% in resistance. The number of girders not passing the moment rat- ings is larger than those not passing the shear rating. Most gird- ers with ratings less than 1.0 are non-composite, for example, for the AASHTO Type 3 truck 180 of the 211 girders with an LRFR moment rating less than 1.0 are non-composite. When the bearing stiffener rating is ignored, almost all girders pass the LRFR shear rating for all loads considered even when the existing, higher live load factors are applied. When the proposed live load factors are applied, all girders passed the LRFR shear rating (same as for LFR) and the num- ber of girders not passing the LRFR moment rating dropped but is still higher than the number of girders not passing the LFR rating. 3.9.2 Simple Span Prestressed I-Beams Table 51 shows the effect of changing the LRFR live load factors to those proposed for the 467 simple span prestressed I-beams included in the study. Column 9 shows the number of girders with LRFR ratings less than 1.0 when the longitu- dinal steel rating (Report ID 85004) is ignored. Column 10 shows the percent change in number of girders with LRFR ratings less than 1.0, ignoring the longitudinal steel rating, compared to the number with LFR ratings less than 1.0. Col- umn 11 shows the number of girders controlled by two addi- tional criteria found to have a significant effect. Report ID 85107 corresponds to the service limit state for tension in the bottom of the beam (which is optional or not required for some vehicles but was found to be applied by some state DOTs) and Report ID 85003 corresponds to the shear fric- 74 Total % Change Ignoring 85004 % Change 85107 (M) 85003 (V) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) Moment 25 289 56.53% 95 14.99% 95 n/a n/a n/a Shear a/na/na/n841%89.2339193 Moment 0 188 40.26% 27 5.78% 27 115 0 24.63% Shear %58.319143%82.7531 Moment 0 222 47.54% 32 6.85% 321 33 0 28.48% Shear %70.410214%99.8341 Moment 0 223 47.75% 35 7.49% 351 26 0 26.98% Shear %58.319114%99.8341 Moment 0 231 49.46% 53 11.35% 531 43 0 30.62% Shear %87.529294%94.01152 Moment 0 212 45.40% 39 8.35% 39 124 0 26.55% Shear %87.529274%60.01942 Moment 0 214 45.82% 51 10.92% 51 134 0 28.69% Shear %87.529284%60.01942 Moment 0 185 39.61% 28 6.00% 28 113 0 24.20% Shear %70.410263%17.7731 Moment 0 246 52.68% 73 15.63% 73 158 0 33.83% Shear %41.831467%94.61083 Moment 0 120 25.70% 68 14.56% 68 90 0 19.27% %12.6110484%24.95511Shear Moment 0 125 26.77% 73 15.63% 73 102 0 21.84% %00.697344%46.9459Shear Moment 6 216 44.97% 1723 5.55% 172 194 6 40.26% %41.8442898%60.6191144Shear Design 467 # of girders with LFR < 1.0 # of Girders Type IL-01 OR-06 Special Permit WA-02 Using Existing Load Factors Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 TX-04 % Change # of girders with LFR < 1.0 # of girders w/ LRFR < 1.0 EffectVehicle Vehicle Type Si m pl e Sp an P re st re ss ed C on cr et e I B ea m s # of girders w/ LRFR < 1.0 HL-93 Table 51. Simple span prestressed I beams—effect of proposed live load factors.

tion rating between the girder and composite slab. Column 12 contains the number of girders with LRFR ratings less than 1.0 when the proposed load factors are utilized and no rat- ing criteria are ignored; column 13 is the same as Column 6 and contains the number of girders with LFR ratings less than 1.0. Column 14 is the percent change between Column 12 and Column 13. For example, for the WA-02 vehicle, it was determined that if both the longitudinal steel rating and the service limit state are ignored, seven girders will have rat- ings less than 1.0 (very similar to the LFR number of six). Thirty-four girders have LRFR shear ratings that are less than 1.0 for the WA-02 vehicle when the shear friction rat- ing is ignored. 3.9.3 Simple Span Prestressed Box Beams Table 52 shows the effect of changing the LRFR live load factors to those proposed for the 377 prestressed box beams included in the study. The description of Columns 9 through 14 is similar to that described for Table 51. The service limit state controls a significant portion of the girders with LRFR ratings less than 1.0 when the longitudinal steel rating is ignored. Thus, changing the live load factors for the strength limit state will not have a significant effect on the number of girders with ratings less than 1.0, when the Service III limit state is checked. 3.9.4 Simple Span Reinforced Concrete T-Beams Table 53 shows the effect of changing the LRFR live load factors to those proposed for the 295 reinforced concrete T-beams included in the study. Column 9 shows the number of girders with LRFR ratings less than 1.0 when the longitu- dinal steel rating (Report ID 85004) is ignored. Column 10 shows the percent change in number of girders with LRFR ratings less than 1.0, ignoring the longitudinal steel rating, compared to the number with LFR ratings less than 1.0. Col- umn 11 contains the number of girders with LRFR ratings less than 1.0 when the proposed load factors are utilized and no rat- ing criteria are ignored; Column 12 is the same as Column 6 and contains the number of girders with LFR ratings less 75 Total % Change Ignoring 85004 % Change 85107 (M) 85003 (V) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) Moment 53 156 27.32% 128 19.89% 94 n/a n/a n/a Shear a/na/na/n01%60.412791 Moment 0 54 14.32% 41 10.88% 36 45 0 11.94% Shear %00.0110%35.031 Moment 0 55 14.59% 44 11.67% 42 47 0 12.47% Shear %00.0110%35.031 Moment 0 65 17.24% 52 13.79% 47 54 0 14.32% Shear %00.0110%35.031 Moment 0 87 23.08% 71 18.83% 65 76 0 20.16% Shear %35.0130%33.161 Moment 0 73 19.36% 59 15.65% 54 63 0 16.71% Shear %72.0120%33.161 Moment 1 102 26.79% 91 23.87% 72 96 1 25.20% Shear %72.0120%08.041 Moment 0 56 14.85% 44 11.67% 42 48 0 12.73% Shear %00.0110%35.031 Moment 1 132 34.75% 117 30.77% 87 122 1 32.10% Shear %35.0352%54.3613 Moment 1 89 23.34% 83 21.75% 69 85 1 22.28% %08.08111%21.2618raehS Moment 2 92 23.87% 88 22.81% 71 90 2 23.34% %00.0111%00.011raehS Moment 19 166 38.99% 162 37.93% 125 161 19 37.67% %75.561734%69.76461raehS Using Existing Load Factors Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 Type # of Girders TX-04 # of girders w/ LRFR < 1.0 % Change # of girders with LFR < 1.0 # of girders w/ LRFR < 1.0 EffectVehicle Vehicle Type IL-01 OR-06 Si m pl e Sp an P re st re ss ed C on cr et e Bo x Be am s Special Permit WA-02 # of girders with LFR < 1.0 Design -93 377 HL Table 52. Simple span prestressed box beams—effect of proposed live load factors.

than 1.0. Column 13 is the percent change between Column 11 and Column 12. 3.9.5 Simple Span Reinforced Concrete Slabs Table 54 shows the effect of changing the LRFR live load factors to those proposed for the 99 simple span reinforced concrete slabs included in the study. The information in Columns 9 through 13 is similar to that described for Table 53. The table shows that ignoring the longitudinal steel rating sig- nificantly reduces the number of slabs with LRFR ratings less than 1.0. 3.9.6 Continuous Span Steel Girders Table 55 shows the effect of changing the load factors to those proposed for the 418 continuous span steel girders included in the study. The information in Columns 9 through 13 is similar to that described in Table 50. 3.9.7 Continuous Span Reinforced Concrete Slabs Table 56 shows the effect of changing the LRFR live load factors to those proposed for the 105 continuous reinforced concrete slabs included in the study. The information in Columns 9 through 13 is similar to that described in Table 53. 3.9.8 Continuous Span Prestressed Concrete I-Beams Table 57 shows the effect of changing the LRFR live load fac- tors to those proposed for the 238 continuous span prestressed I beams included in the study. The information in Columns 9 through 14 is similar to that described for Table 51. 76 Total % Change Ignoring 85004 % Change (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Moment 1312 69 46.78% 220 30.17% n/a n/a n/a Shear 1691 94 8.47% n/a n/a n/a Moment 9 124 38.98% 56 15.93% 73 9 21.69% Shear 21 68 15.93% 40 21 6.44% Moment 7 88 27.46% 32 8.47% 48 7 13.90% Shear 17 51 11.53% 31 17 4.75% Moment 8 106 33.22% 49 13.90% 68 8 20.34% Shear 21 62 13.90% 34 21 4.41% Moment 22 150 43.39% 93 24.07% 91 22 23.39% Shear 27 79 17.63% 59 27 10.85% Moment 21 139 40.00% 80 20.00% 84 21 21.36% Shear 26 76 16.95% 56 26 10.17% Moment 38 178 47.46% 122 28.47% 103 38 22.03% Shear 27 81 18.31% 58 27 10.51% Moment 19 120 34.24% 59 13.56% 68 19 16.61% Shear 21 68 15.93% 41 21 6.78% Moment 45 216 57.97% 139 31.86% 133 45 29.83% Shear 49 138 30.17% 79 49 10.17% Moment 56 190 45.42% 123 22.71% 153 56 32.88% Shear 56 118 21.02% 94 56 12.88% Moment 61 200 47.12% 139 26.44% 159 61 33.22% Shear 63 126 21.36% 99 63 12.20% Moment 80 221 47.80% 160 27.12% 188 80 36.61% Shear 86 166 27.12% 127 86 13.90% TX-04 Special Permit WA-02 Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 Using Existing Load Factors EffectVehicle Vehicle Type # of Girders Type % Change** # of girders w/ LFR < 1.0 # of girders w/ LRFR < 1.0 # of girders w/ LRFR < 1.0# of girders w/ LFR < 1.0 IL-01 OR-06 Si m pl e Sp an R ei nf or ce d C on cr et e T -B ea m s 295 Design -93HL Table 53. Simple span reinforced concrete T-beams—effect of proposed live load factors.

Generally, Tables 50 through 57 indicate that a significant percentage of girders that passed rating under the LFR and pro- duced rating factors below 1.0 for the LRFR were controlled by criteria that were not checked under the LFR method of rating. Some of these criteria are not known to have caused problems in the past. When these criteria are ignored in the LRFR rating, the difference in the number of bridges not passing the LRFR rating, as compared to the number of those not passing the LFR rating, decreases significantly. In addition, when the LRFR load factors for live load are changed from those currently in the MBE to the proposed lower load factors associated with the target reliability index assumed in the development of the MBE, the number of bridges not passing the LRFR rating is fur- ther reduced. The load factor for live load in the MBE for legal and per- mit loads is dependent on the ADTT while the load factor for live load in the LFR method is independent of ADTT. The MBE includes three ADTT categories: 100, 1,000, and 5,000. Tables 50 through 57 are based on assuming an ADTT of 1,000. The numbers of bridges not passing the LRFR rating in these tables will increase if the load factors corresponding to ADTT of 5,000 are assumed while these numbers will decrease when the load factors corresponding to an ADTT of 100 are assumed. 3.9.9 Average Ratio of Rating Factors for Existing and Proposed Live Load Factors The following sections show the average reduction in rat- ing factor using the existing live load factors in the MBE and those proposed as a result of this research. Each section con- tains a table showing the effects of the proposed load factors for each vehicle (no revisions are proposed to the live load factor for the design load). The effects of using the proposed load factor on the distribution of ratings (similar to those 77 Total % Change Ignoring 85004 % Change (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Moment 27 64 37.37% 46 19.19% n/a n/a n/a Shear 2 5 3.03% n/a n/a n/a Moment 0 23 23.23% 4 4.04% 9 0 9.09% Shear %10.101%10.110 Moment 0 10 10.10% 2 2.02% 7 0 7.07% Shear %10.101%10.110 Moment 0 14 14.14% 3 3.03% 9 0 9.09% Shear %10.101%10.110 Moment 2 27 25.25% 11 9.09% 13 2 11.11% Shear %10.101%10.110 Moment 1 24 23.23% 7 6.06% 10 1 9.09% Shear %10.101%10.110 Moment 5 32 27.27% 20 15.15% 19 51 4.14% Shear %10.101%10.110 Moment 0 13 13.13% 2 2.02% 8 0 8.08% Shear %10.101%10.110 Moment 8 43 35.35% 22 14.14% 27 8 19.19% Shear %20.202%50.550 Moment 14 31 17.17% 21 7.07% 28 14 14.14% %40.404%50.550raehS Moment 14 33 19.19% 21 7.07% 28 14 14.14% %40.404%50.550raehS Moment 16 37 21.21% 23 7.07% 29 16 13.13% %40.404%50.550raehS Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 Using Existing Load Factors TX-04 Special Permit WA-02 tceffEepyT Vehicle Vehicle Type # of Girders % Change # of girders w/ LFR < 1.0 # of girders w/ LRFR < 1.0 # of girders w/ LFR < 1.0 # of girders w/ LRFR < 1.0 IL-01 OR-06 Si m pl e Sp an R ei nf or ce d C on cr et e S la b Br id ge s 99 Design HL-93 Table 54. Simple span reinforced concrete slabs—effect of proposed live load factors.

shown in Section 3.6) are presented in Appendix M. For the special permit vehicles, only the values corresponding to a target reliability index of 2.5 are shown. 3.9.9.1 Simple Span Steel Girders Table 58 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the live load factors proposed. The proposed live load factors increase the ratio from the range of 0.71 to 0.76 to between 0.90 and 0.97 for moment for legal and routine permit vehicles. For special permit vehicles, the range increases from between 1.12 and 1.20 to between 1.26 and 1.35. The proposed live load factors increase the ratio from the range of 0.50 to 0.56 to between 0.64 and 0.76 for shear for legal and routine permit vehi- cles. For special permit vehicles, the range increases from between 0.78 and 0.81 to between 0.88 and 0.90; the aver- age ratio is reduced due to the effect of the bearing stiffener rating. 3.9.9.2 Simple Span Prestressed Concrete I-Girders Table 59 shows the average of the ratio between the LRFR rat- ing and the LFR rating for the existing live load factors in the MBE and the live load factors proposed. The proposed live load factors result in a small increase in the average ratio for moment. This is due to either the effect of shear on the longitudinal steel causing extremely low ratings or the controlling rating being a service limit state which is unaffected by the pro- posed changes. The average ratio for the routine permit and legal vehicles is between 0.30 and 0.43, while for the special permit vehicles it is between 0.55 and 0.58. The average ratio of LRFR shear rating to LFR shear rating increased and is above 0.92 for all vehicles. 3.9.9.3 Simple Span Prestressed Concrete Box-Girders Table 60 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in 78 Total % Change Ignoring 80007 % Change (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Moment 89 145 13.40% n/a n/a n/a Shear 29 100 16.99% 26 -0.72% n/a n/a n/a Moment 2 24 5.26% 14 2 2.87% Shear 0 27 6.46% 10 2.39% 20 0 4.78% Moment 2 27 5.98% 14 2 2.87% Shear 5 45 9.57% 11 1.44% 31 5 6.22% Moment 3 30 6.46% 18 3 3.59% Shear 5 40 8.37% 18 3.11% 28 5 5.50% Moment 10 37 6.46% 23 10 3.11% Shear 5 45 9.57% 13 1.91% 32 5 6.46% Moment 7 32 5.98% 17 7 2.39% Shear 5 39 8.13% 11 1.44% 28 5 5.50% Moment 9 33 5.74% 24 9 3.59% Shear 3 36 7.89% 11 1.91% 23 3 4.78% Moment 3 25 5.26% 12 3 2.15% Shear 1 28 6.46% 10 2.15% 20 1 4.55% Moment 24 40 3.83% 26 24 0.48% Shear 5 47 10.05% 13 1.91% 27 5 5.26% Moment 44 35 -2.15% 28 44 -3.83% Shear 14 50 8.61% 17 0.72% 41 14 6.46% Moment 45 40 -1.20% 33 45 -2.87% Shear 17 54 8.85% 16 -0.24% 49 17 7.66% Moment 141 122 -4.55% 75 141 -15.79% Shear 45 97 12.44% 59 3.35% 79 45 8.13% Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 Effect Vehicle # of girders w/ LRFR < 1.0 Using Existing Load Factors Design Vehicle Type # of Girders Type HL-93 418 IL-01 OR-06 TX-04 WA-02 Special Permit C on tin uo us S pa n St ee l % Change # of girders w/ LFR < 1.0 # of girders w/ LRFR < 1.0 # of girders w/ LFR < 1.0 Table 55. Continuous span steel—effect of proposed live load factors.

ranged from 0.62 to 0.64 and using the proposed live load fac- tors has increased to 0.70–0.71. For shear, the average ratio increased from 0.72–0.81 to 0.86–1.0 for all vehicle types. 3.9.9.5 Simple Span Reinforced Concrete Slab Bridges Table 62 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the proposed live load factors. The proposed live load factors result in an increase in the average ratio for moment from 0.63–0.67 to 0.80–0.86 for the routine permit and legal vehicles. The average ratio of flexure ratings for the special permit vehicles increased from 0.79–0.81 to 0.89–0.91. For shear, the average ratio using the current load factors was between 1.05 and 1.11 for the routine permit and legal vehi- cles. This has increased to between 1.34 and 1.42 using the proposed load factors. For special permit vehicles, the ratio increased from 1.17–1.19 to 1.31–1.34. 79 Total % Change Ignoring 85004 % Change (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Moment 66 96 28.57% 80 13.33% n/a n/a n/a Shear 43 74 29.52% n/a n/a n/a Moment 8 51 40.95% 18 9.52% 24 8 15.24% Shear 0 5 4.76% 1 0 0.95% Moment 8 42 32.38% 10 1.90% 26 8 17.14% Shear 0 1 0.95% 1 0 0.95% Moment 9 71 59.05% 22 12.38% 36 9 25.71% Shear 0 5 4.76% 2 0 1.90% Moment 14 70 53.33% 21 6.67% 66 14 49.52% Shear 0 8 7.62% 5 0 4.76% Moment 9 45 34.29% 11 1.90% 42 9 31.43% Shear 0 6 5.71% 2 0 1.90% Moment 13 61 45.71% 23 9.52% 58 13 42.86% Shear 0 10 9.52% 5 0 4.76% Moment 9 38 27.62% 12 2.86% 36 9 25.71% Shear 0 5 4.76% 1 0 0.95% Moment 20 71 48.57% 35 14.29% 69 20 46.67% Shear 3 22 18.10% 10 3 6.67% Moment 40 88 45.71% 59 18.10% 87 40 44.76% Shear 3 34 29.52% 23 3 19.05% Moment 34 85 48.57% 53 18.10% 84 34 47.62% Shear 3 36 31.43% 27 3 22.86% Moment 58 97 37.14% 80 20.95% 97 58 37.14% Shear 9 68 56.19% 53 9 41.90% HL-93 105 C on tin uo us S pa n R ei nf or ce d C on cr et e Sl ab B rid ge s # of girders with LFR < 1.0 # of Girders Vehicle Type Vehicle OR-06 WA-02 Legal AASHTO Type 3 AASHTO Type 3-3 Design Special Permit Routine Permit Effect # of girders w/ LRFR < 1.0 # of girders with LFR < 1.0 % Change** IL-01 Using Existing Load Factors Using Proposed Load Factors AASHTO Type 3S2 DE-07 FL-04 NC-21 NM-04 TX-04 Type # of girders w/ LRFR < 1.0 Table 56. Continuous reinforced concrete slabs—effect of proposed live load factors. the MBE and the proposed live load factors. The proposed live load factors result in a small increase in the average ratio for moment. This is due to either the effect of shear on the longitudinal steel causing extremely low ratings or the con- trolling rating being a service limit state which is unaffected by the proposed changes. The average ratio for the routine permit and legal vehicles is between 0.47 and 0.51 while the ratio for all special permit vehicles is 0.66. The average ratio of LRFR shear rating to LFR shear rating increased and is above 1.27 for all vehicles. 3.9.9.4 Simple Span Reinforced Concrete T-Beams Table 61 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the proposed live load factors. The proposed live load factors result in a small increase in the average ratio for moment from 0.49–0.56 to 0.62–0.71 for the routine permit and legal vehicles. For the special permit vehicles the ratio

80 Total % Change Ignoring 85004 % Change 85107 (M) 85003 (V) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) Moment 19 226 86.97% 75 23.53% 15.00 n/a n/a n/a Shear 36 113 32.35% 90.00 n/a n/a n/a Moment 0 172 72.27% 2 0.84% 2.00 133 0 55.88% Shear 0 45 18.91% 45.00 40 0 16.81% Moment 0 178 74.79% 2 0.84% 2.00 143 0 60.08% Shear 0 49 20.59% 49.00 36 0 15.13% Moment 0 181 76.05% 3 1.26% 3.001 42 0 59.66% Shear 0 50 21.01% 50.00 39 0 16.39% Moment 0 190 79.83% 6 2.52% 6.00 150 0 63.03% Shear 1 51 21.01% 51.00 44 1 18.07% Moment 0 180 75.63% 5 2.10% 5.00 141 0 59.24% Shear 0 50 21.01% 50.00 43 0 18.07% Moment 0 185 77.73% 11 4.62% 11.00 145 0 60.92% Shear 0 51 21.43% 51.00 44 0 18.49% Moment 0 171 71.85% 3 1.26% 3.00 136 0 57.14% Shear 0 46 19.33% 46.00 39 0 16.39% Moment 0 191 80.25% 14 5.88% 14.00 150 0 63.03% Shear 0 58 24.37% 56.00 46 0 19.33% Moment 0 150 63.03% 14 5.88% 14.00 134 0 56.30% Shear 4 53 20.59% 49 47 4 18.07% Moment 3 158 65.13% 14 4.62% 12.00 140 3 57.56% Shear 3 51 20.17% 48.00 43 3 16.81% Moment 13 186 72.69% 64 21.43% 55.00 167 13 64.71% Shear 28 80 21.85% 67.00 70 28 17.65% Using Proposed Load Factors Legal AASHTO Type 3 AASHTO Type 3-3 AASHTO Type 3S2 Routine Permit DE-07 FL-04 NC-21 NM-04 TX-04 # of girders w/ LRFR < 1.0 # of girders with LFR < 1.0 % Change** Effect Design -93 # of girders with LFR < 1.0 OR-06 Special Permit WA-02 238 C on tin uo us S pa n Pr es tre ss ed C on cr et e I-B ea m # of girders w/ LRFR < 1.0 Vehicle Type Vehicle IL-01 Using Existing Load Factors Type # of Girders HL Table 57. Continuous prestressed concrete I-beams—effect of proposed live load factors. Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.98 N/A 0.65 N/A DE-07 0.76 0.97 0.55 0.71 FL-04 0.76 0.97 0.55 0.71 IL-01 1.12 1.26 0.79 0.88 NC-21 0.75 0.97 0.56 0.72 NM-04 0.76 0.97 0.56 0.72 OR-06 1.20 1.35 0.81 0.90 TX-04 0.75 0.97 0.56 0.72 WA-02 1.12 1.26 0.78 0.88 Type 3 0.71 0.90 0.52 0.67 Type 3-3 0.71 0.90 0.50 0.64 Type 3S2 0.71 0.92 0.51 0.76 Table 58. Comparison of average LRFR/LFR ratio for simple span steel girders for existing and proposed load factors.

81 Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.62 N/A 0.78 N/A DE-07 0.30 0.35 0.79 1.01 FL-04 0.29 0.34 0.81 1.04 IL-01 0.52 0.55 1.08 1.24 NC-21 0.31 0.43 0.82 0.92 NM-04 0.28 0.30 0.83 0.96 OR-06 0.52 0.56 1.07 1.20 TX-04 0.31 0.43 0.80 1.32 WA-02 0.56 0.58 1.00 1.12 Type 3 0.26 0.31 0.81 1.02 Type 3-3 0.25 0.30 0.78 1.00 Type 3S2 0.26 0.31 0.77 0.97 Table 59. Comparison of average LRFR/LFR rating ratio for simple span prestressed concrete I-girders for existing and proposed live load factors. Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.76 N/A 0.93 N/A DE-07 0.48 0.50 1.04 1.33 FL-04 0.48 0.51 1.06 1.36 IL-01 0.64 0.66 1.30 1.46 NC-21 0.49 0.51 1.07 1.37 NM-04 0.48 0.50 1.11 1.41 OR-06 0.65 0.66 1.58 1.77 TX-04 0.49 0.51 0.99 1.27 WA-02 0.65 0.66 1.18 1.32 Type 3 0.46 0.48 1.06 1.34 Type 3-3 0.44 0.47 1.05 1.33 Type 3S2 0.45 0.48 1.03 1.31 Table 60. Comparison of average LRFR/LFR ratio for simple span prestressed concrete box-girders for existing and proposed load factors. Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.64 N/A 0.83 N/A DE-07 0.53 0.67 0.76 0.97 FL-04 0.53 0.67 0.76 0.98 IL-01 0.62 0.70 0.80 0.89 NC-21 0.56 0.71 0.76 0.97 NM-04 0.53 0.68 0.78 1.00 OR-06 0.64 0.71 0.81 0.90 TX-04 0.53 0.68 0.72 0.93 WA-02 0.63 0.71 0.76 0.86 Type 3 0.50 0.64 0.76 0.97 Type 3-3 0.49 0.62 0.78 0.99 Type 3S2 0.50 0.64 0.77 0.97 Table 61. Comparison of average LRFR/LFR ratios for simple span reinforced concrete T-beams for existing and proposed load factors.

3.9.9.6 Continuous Span Steel Girder Bridges Table 63 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the proposed live load factors. The proposed live load factors result in an increase in the average ratio for moment from 0.81–0.88 to 1.02–1.12 for the AASHTO legal and routine permit vehicles. For shear, the average ratio increased from 0.63–0.69 to 0.79–0.89 for the legal and rou- tine permit vehicles. For the special permit vehicles, the aver- age moment ratio increased from 1.25–1.28 to 1.40–1.44 and for shear increased from 0.94–0.96 to 1.06–1.08. 3.9.9.7 Continuous Span Reinforced Concrete Slab Bridges Table 64 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the proposed live load factors. The proposed live load factors result in a very small increase in the average ratio for moment for the routine and special permit vehicles. For the AASHTO Legal Trucks, the average ratio increased from 0.46–0.50 to 0.59–0.63. For shear, the average ratio increased from 0.74–0.85 to 0.95–1.12 for the routine permit and AASHTO Legal vehicles. The average ratio of shear rat- ings for the special permit vehicles increased from 0.71–0.78 to 0.80–0.87. 3.9.9.8 Continuous Span Prestressed Concrete I-Girder Bridges Table 65 shows the average of the ratio between the LRFR rating and the LFR rating for the existing live load factors in the MBE and the proposed live load factors. The proposed live load factors result in a small increase in the average ratio for moment for the AASHTO legal and routine permit vehi- cles. The ratio for moment generally increased from 0.2–0.25 to 0.25–0.32. For shear, the average ratio increased from 0.76–0.80 to 0.96–1.02 for the routine permit and AASHTO legal vehicles. For the special permit vehicles, the average moment rating increased from 0.43–0.56 to 0.47–0.61 and the average shear rating increased from 1.02–1.12 to 1.14–1.25. The small increase in moment ratios is a result of including the ratings for service limit states (which is unaffected by changing the strength load factor) and the effect of shear on longitudinal steel. 82 Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.73 N/A 1.27 N/A DE-07 0.66 0.85 1.10 1.41 FL-04 0.66 0.85 1.10 1.40 IL-01 0.81 0.90 1.19 1.34 NC-21 0.67 0.86 1.08 1.39 NM-04 0.64 0.82 1.11 1.42 OR-06 0.81 0.91 1.18 1.32 TX-04 0.65 0.84 1.05 1.34 WA-02 0.79 0.89 1.17 1.31 Type 3 0.63 0.80 1.08 1.37 Type 3-3 0.63 0.80 1.10 1.40 Type 3S2 0.64 0.82 1.10 1.40 Table 62. Comparison of average LRFR/LFR ratios for simple span reinforced concrete slab bridges for existing and proposed load factors. Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.92 N/A 0.75 N/A DE-07 0.86 1.10 0.67 0.86 FL-04 0.86 1.10 0.67 0.86 IL-01 1.28 1.44 0.96 1.07 NC-21 0.88 1.12 0.69 0.89 NM-04 0.87 1.12 0.68 0.88 OR-06 1.27 1.42 0.96 1.08 TX-04 0.88 1.12 0.69 0.89 WA-02 1.25 1.40 0.94 1.06 Type 3 0.85 1.07 0.66 0.84 Type 3-3 0.81 1.02 0.63 0.79 Type 3S2 0.82 1.04 0.64 0.81 Table 63. Comparison of average LRFR/LFR ratios for continuous span steel girder bridges for existing and proposed load factors.

83 Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.62 N/A 0.79 N/A DE-07 0.56 0.57 0.79 1.01 FL-04 0.56 0.57 0.81 1.04 IL-01 0.57 0.57 0.78 0.87 NC-21 0.59 0.60 0.80 1.02 NM-04 0.58 0.59 0.87 1.12 OR-06 0.58 0.58 0.77 0.86 TX-04 0.59 0.59 0.74 0.95 WA-02 0.56 0.57 0.71 0.80 Type 3 0.50 0.63 0.84 1.07 Type 3-3 0.46 0.59 0.85 1.09 Type 3S2 0.48 0.60 0.82 1.04 Table 64. Comparison of average LRFR/LFR ratios for continuous span reinforced concrete slab bridges for existing and proposed load factors. Moment (LRFR/LFR) Shear (LRFR/LFR) Vehicle Existing Proposed Existing Proposed HL-93 0.42 N/A 0.81 N/A DE-07 0.24 0.31 0.78 1.00 FL-04 0.23 0.29 0.80 1.02 IL-01 0.43 0.47 1.12 1.25 NC-21 0.24 0.30 0.78 0.99 NM-04 0.21 0.27 0.80 1.02 OR-06 0.49 0.54 1.11 1.24 TX-04 0.25 0.32 0.79 1.01 WA-02 0.56 0.61 1.02 1.14 Type 3 0.20 0.25 0.79 1.00 Type 3-3 0.21 0.26 0.76 0.97 Type 3S2 0.21 0.27 0.76 0.96 Table 65. Comparison of average LRFR/LFR ratios for continuous span prestressed concrete I-girder bridges for existing and proposed load factors.