Practices for Ensuring the Smoothness of Concrete Bridge Decks (2022)

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26 This chapter presents the results from the survey that was sent to state DOTs. The information obtained from the survey is presented in the following three sections in this chapter: • Smoothness Practices for Bridges: This section presents the state DOT practices for evaluating the smoothness of the finished concrete bridge deck after construction. • Storage of Roughness Data of Bridges and the Use of the Data: This section presents informa- tion on the storage of roughness data of bridges collected during the network-level survey of the highway system and the use of these data. • Maintenance and Rehabilitation Activities to Address Roughness of Bridges: This section presents maintenance and rehabilitation procedures used by state DOTs to maintain the smoothness of bridge decks. In this chapter, responses by the state DOTs are presented as percentages. When computing the percentage, the standard procedure for rounding decimals to an integer was followed. How- ever, this procedure sometimes resulted in the total responses being not being equal to 100%. When such a situation occurred, one or occasionally two of the responses that should have been rounded up were rounded down in order for the total responses to add up to 100%. Smoothness Practices for Bridges Introduction Based on the responses from the state DOTs, the practices for evaluating the smoothness of a new concrete bridge deck can be divided into eight categories, as shown in Table 1. Two state DOTs indicated they do not have a smoothness requirement for bridges. The most common practice for evaluating the smoothness of the bridge deck is to only use a straightedge, with 17 state DOTs (43% of the responding DOTs) indicating they follow this practice. Note that some state DOTs that have smoothness requirements based on IRI or profilograph measure- ments also have a straightedge-based requirement in their specification. A rolling straightedge-based smoothness requirement is used by six state DOTs (15% of responding DOTs), with three of these state DOTs requiring the use of an actual rolling straight- edge, one state DOT using a rolling straightedge simulation on inertial profiler data, and the other state DOT using a rolling straightedge simulation on walking profiler data. One state DOT has a smoothness requirement that is based on either the straightedge or a rolling straightedge. Smoothness requirements based on profilograph measurements are used by eight state DOTs (20% of the responding DOTs), with IRI-based requirements being used by six state DOTs (15% of the responding DOTs). Details about each of these categories are presented separately in this section. C H A P T E R 3 State of the Practice

State of the Practice 27   Smoothness Not Evaluated Two state DOTs (5% of responding DOTs), which are DOTs in Indiana and New Hampshire, indicated they do not have a smoothness requirement for a finished concrete bridge deck. New Hampshire DOT indicated an AC overlay is placed on concrete bridges in the state, which is the reason why they do not have a smoothness requirement for concrete bridge decks. Smoothness Evaluated Using a Straightedge Only Seventeen state DOTs (44% of responding DOTs) indicated they only use a straightedge to evaluate the smoothness of a new concrete bridge deck. Note that some state DOTs that use IRI or profilograph measurements to evaluate smoothness also have a straightedge-based requirement in their smoothness specification. This section only presents the information for the 17 state DOTs that only use a straightedge to evaluate smoothness. Table 2 shows the length of the straightedge and the allowable tolerance (i.e., maximum allowable deviation from the bottom of the straight- edge to the top of the pavement when the straightedge is placed parallel to the travel direction) that is used by these state DOTs. All state DOTs that use only a straightedge for evaluating smoothness use a straightedge 10 ft. long, except for one state DOT that uses a straightedge 12 ft. long. The most common criterion that is used to evaluate smoothness is a maximum deviation of ⅛ in. from the bottom of the straightedge to the top of the pavement, with 58% of the state DOTs that only use a straightedge to evaluate smoothness indicating they use this requirement. Method Used to Evaluate Smoothness State DOTs Using the Method Number of State DOTs Percentage of Responding State DOTs (%) Smoothness not evaluated Indiana, New Hampshire 2 5 Only a straightedge useda Alabama, Alaska, Arkansas, Colorado, Connecticut, Louisiana, Maine, Maryland, Massachusetts, Montana, New Mexico, New York, Pennsylvania, Texas, Vermont, Washington, Wyoming 17 44 Rolling straightedge Kansas, Kentucky, Missouri 3 7 Straightedge or rolling straightedge Delaware 1 3 Rolling straightedge simulation on inertial profiler data Rhode Island 1 3 Rolling straightedge simulation on walking profiler data New Jersey 1 3 IRI b Michigan, Minnesota, Nevada, Ohio, Tennessee, Utah 6 15 Profilograph measurements c Florida, Georgia, Hawaii, Illinois, Iowa, Mississippi, Nebraska, South Carolina 8 20 Total 39 100 a Some state DOTs that use IRI or profilograph measurements also have a straightedge-based requirement. Such state DOTs are not included in this category. b Some state DOTs indicated that if an IRI-based specification is not used for a bridge, a straightedge-based specification is used. c Some state DOTs indicated that if a PI-based specification is not used for a bridge, a straightedge-based specification is used. Table 1. State DOT practices for evaluating the smoothness of new concrete bridge decks.

28 Practices for Ensuring the Smoothness of Concrete Bridge Decks Smoothness Evaluated with a Rolling Straightedge The Kansas, Kentucky, and Missouri DOTs (7% of responding DOTs) indicated they use a rolling straightedge to check the smoothness of a new bridge deck. These DOTs use a 10-ft. roll- ing straightedge. The specified requirement is a deviation of less than ⅛ in. at the center of the rolling straightedge based on the datum established by the wheels at the two ends. Smoothness Evaluated with a Straightedge or a Rolling Straightedge Delaware DOT (3% of responding DOTs) indicated it uses a straightedge or a rolling straight- edge to check the smoothness of a new bridge deck. The length of the straightedge as well as the length of the rolling straightedge is 10 ft. The specified requirement for the straightedge is a deviation of less than ¼ in. from the bottom of the straightedge to the top of the pavement when the straightedge is placed parallel to the travel direction on the bridge. The specified requirement for the rolling straightedge is a deviation of less than ¼ in. at the center of the rolling straightedge based on the datum established by the wheels at the two ends. Smoothness Evaluated Using a Rolling Straightedge Simulation on Inertial Profiler Data Rhode Island DOT (3% of responding DOTs) indicated it performs a rolling straightedge simulation on data collected by an inertial profiler to check the smoothness of a new bridge deck. The length of the simulated rolling straightedge is 10 ft., while the specified requirement is a deviation of less than ⅛ in. at the center of the rolling straightedge based on the datum estab- lished by the wheels at the ends. Smoothness Evaluated Using a Rolling Straightedge Simulation on Walking Profiler Data New Jersey DOT (3% of responding DOTs) uses a SurPRO, which is a walking profiler manufactured by International Cybernetics Corporation to collect data on new bridge decks. Thereafter, a 10-ft. rolling straightedge simulation is performed on the data. The requirement is a deviation of less than ⅛ in. at the center of the rolling straightedge based on the datum established by the wheels at the ends. Details about the procedure followed by the New Jersey DOT for collecting the data, performing the straightedge simulation, and analyzing the results obtained from the simulation are presented in Chapter 4, which describes case examples. State DOT Length of Straightedge (ft.) Maximum Deviation (in.) Number of State DOTs Percentage of State DOTs Only Using Straightedge (%) Massachusetts, Wyoming 10 2 12 Alabama, Alaska, Arkansas, Connecticut, Louisiana, Maine, Maryland, Texas, Vermont, Washington 10 10 58 New York 10 1 6 Colorado, Montana, New Mexico 10 3 18 Pennsylvania 12 1 6 Total 17 100 Table 2. Straightedge requirements for the state DOTs that only use a straightedge to evaluate smoothness.

State of the Practice 29   Smoothness Evaluated Using the International Roughness Index Overview Six state DOTs (15% of responding DOTs) indicated they use an IRI-based smoothness speci- fication for concrete bridge decks. These state DOTs include those in Michigan, Minnesota, Nevada, Ohio, Tennessee, and Utah. The IRI-based smoothness specification may consist of • A MIRI-based criterion and a localized roughness criterion that is based on IRI or another method, or • Only a localized roughness criterion based on IRI. More details about the procedures used by Nevada DOT, Ohio DOT, and Utah DOT are presented in Chapter 4, which includes case examples. Alabama DOT, which currently uses a straightedge for evaluating smoothness, indicated they have used an IRI-based smoothness specification on one project. Louisiana DOT, which currently uses the straightedge to evaluate smoothness, indicated they have developed a draft IRI-based smoothness specification, but it has not been finalized and published. Information about the IRI-based specification used for the one project in Alabama and the information in the draft Louisiana DOT specification are also presented in this section. Limits of Application of Smoothness Specification The limits over which the smoothness specification is applied (i.e., bridge deck only; bridge deck and approach slabs; bridge deck, approach slabs, and a specified length of pavement before the entry approach slab and after the exit approach slab) varied among the state DOTs. Table 3 shows the limits over which the smoothness specification is applied by the different state DOTs. The Tennessee DOT specification considers 150 ft. on either side of the bridge deck to be included in the smoothness evaluation unless a shorter distance is specified by the engineer or is shown on the plans. The distance of pavement considered in the smoothness specifica- tion before the entry approach slab and after the exit approach slab is 25 ft. in the Ohio DOT and Utah DOT specifications, while this value is 50 ft. in the Nevada DOT specification. For all cases, the application of the smoothness specification to the pavement before the entry approach slab and after the exit approach slab is used only if the contract for the bridge work includes the work associated with the pavement before the entry approach slab and after the exit approach slab. State DOT Limits of Application of Smoothness Specification Number of State DOTs Percentage of State DOTs (%) Alabama, Michigan Bridge deck only 2 25 Louisiana, Minnesota Bridge deck and approach slabs 2 25 Tennessee Bridge deck and a specified distance on both sides of the bridge deck 1 12 Nevada, Ohio, Utah Bridge deck, approach slab, and a specified distance of pavement before the entry approach slab and after the exit approach slab 3 38 Total 8 100 Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 3. Limits of application of the IRI-based specification.

30 Practices for Ensuring the Smoothness of Concrete Bridge Decks Functional Class of Highways on which the Bridge is Located and Speed Limit The smoothness specification did not vary based on the functional class of the roadway on which the bridge is located except in the Michigan DOT and Tennessee DOT specifications. The Michigan DOT smoothness specification is applied when the bridge is on a highway system where the speed limit is more than 50 mph. In Tennessee, the localized roughness requirements were different for roads with a speed limit greater than 45 mph and for those with a speed limit less than 45 mph. The draft specification developed by the Louisiana DOT was applicable to all bridges irrespective of the functional class of the roadway on which the bridge is located. Minimum Length of Bridge for Application of Smoothness Specification The smoothness specification was applied to all bridges irrespective of the length except in Minnesota. In Minnesota, the smoothness specification was applied only if the length of the bridge was greater than 2,500 ft., and a straightedge-based smoothness requirement was used for shorter bridges. The draft specification developed by Louisiana DOT indicated the smoothness specification will be applied only to bridges that are 300 ft. or greater in length. Smoothness Data Collection Data collected by an inertial profiler along the two wheelpaths in a travel lane are needed for the computation of MIRI. Table 4 shows the parties that collect the smoothness data. In Nevada, the contractor hires a third party to collect the data if the contractor does not possess the equipment for collecting the data. In Alabama, the smoothness data are collected by a third party hired by the contractor. In the states where data collection is performed by the contractor or a third party hired by the contractor, the equipment that is used for data collection must be certified by the state DOT, and the equipment must be operated by an operator who is also certified by the state DOT. In these states, verification of the data collected by the contractor or a third party hired by the contractor is performed by the state DOT. In Alabama, Minnesota, Nevada, Ohio, and Utah, there is no time limit specified when the data should be collected after construction. In Michigan and Tennessee, data must be collected within 7 days after construction. The draft specification developed by Louisiana DOT has no time limit specified for when data should be collected after construction. MIRI Reporting Interval The MIRI reporting interval for each state DOT is shown in Table 5. The Michigan and Tennessee DOTs require MIRI to be reported for the total profiled length of each lane on the bridge. The Alabama, Minnesota, and Utah DOTs require the MIRI to be reported at 0.1-mi. State DOT Party Responsible for Data Collection Number of State DOTs Percentage of State DOTs (%) Michigan, Minnesota, Tennessee DOT 3 38 Louisiana, Nevada, Ohio, Utah Contractor constructing the bridge 4 50 Alabama Third party hired by contractor constructing the bridge 1 12 Total 8 100 Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 4. Party responsible for data collection – MIRI-based specification.

State of the Practice 31   intervals for all travel lanes on the bridge. The draft specification developed by Louisiana DOT indicates MIRI computed at 264-ft. intervals should be reported for each travel lane of the bridge. The Nevada and Ohio DOTs do not have a MIRI-based criterion for smoothness and they only have a localized IRI-based criterion for smoothness. MIRI Criterion for Smoothness The MIRI reporting requirement and the maximum allowable MIRI value for each state DOT are shown in Table 6. The maximum allowable MIRI values ranged from 60 to 130 in./mi. Localized Roughness Requirement The localized roughness requirements used by the state DOTs are summarized in Table 7. A localized roughness criterion based on IRI is not used by Michigan DOT or Minnesota DOT. State DOT MIRI Reporting Interval Number of State DOTs Percentage of State DOTs (%) Michigan, Tennessee Entire profiled lane 2 25 Alabama, Minnesota, Utah 0.1-mi. intervals 3 38 Nevada, Ohio No MIRI requirement. Requirement based on localized roughness 2 25 Louisiana 264-ft. intervals 1 12 Total 8 100 Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 5. MIRI reporting interval. State DOT MIRI Reporting Requirements MIRI Requirement Michigan, Tennessee Entire profiled lane of bridge Less than 130 in./mi. Alabama 0.1-mi. intervals Less than 120 in./mi. Minnesota 0.1-mi. intervals Less than 60 in./mi. Utah 0.1-mi. intervals Less than 90 in./mi. Louisiana 264-ft. intervals Less than 120 in./mi. Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 6. Maximum allowable MIRI values. State DOT Localized Roughness Requirement Alabama 25-ft. moving average IRI, threshold not known Louisiana, Tennessee 25-ft. moving average IRI, threshold varies Michigan Straightedge-based Minnesota Profilograph-based Nevada 25-ft. moving average IRI, threshold less than 175 in./mi. Ohio 25-ft. moving average IRI, histogram-basedrequirement Utah 25-ft. moving average IRI, threshold less than 250 in./mi. Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 7. Localized roughness requirement – IRI-based specification.

32 Practices for Ensuring the Smoothness of Concrete Bridge Decks The localized roughness criterion used by Michigan DOT is based on a straightedge, where sur- face irregulates must be less than ⅛ in. The localized roughness criterion used by Minnesota DOT is based on a profilograph simulation that is performed on data collected by an inertial profiler to detect bumps. The IRI-based localized roughness requirement used by the Alabama, Nevada, Ohio, and Tennessee DOTs and the requirement described in the draft Louisiana DOT specifica- tion apply to each wheelpath in each lane. The localized IRI roughness criterion used by the Alabama, Nevada, Ohio, Tennessee, and Utah DOTs and the localized IRI roughness criterion indicated in the draft specification devel- oped by Louisiana DOT are based on a 25-ft. moving average IRI. The maximum allowable localized IRI value based on a 25-ft. moving average that is used by each state DOT is as follows (note that the value used in Alabama was not available): • Louisiana DOT: The draft specification indicates the maximum allowable IRI value for localized roughness to be 180 in./mi. when there is no joint within the 25-ft. segment, and 250 in./mi. if there is a joint within the 25-ft. segment. • Nevada DOT: The maximum allowable IRI value for localized roughness is 175 in./mi. More details about the procedures used by Nevada DOT are presented in Chapter 4, which describes case examples. • Ohio DOT: Ohio DOT has pay adjustments based on a histogram of localized roughness, where positive and negative pay adjustments are applied. In order to receive full pay, the allowable IRI value for localized roughness must be between 200 and 250 in./mi. for locations without armored joints, and 200 to 300 in./mi. for locations with armored joints. Details about the procedures used by Ohio DOT are presented in Chapter 4, which describes case examples. • Tennessee DOT: The localized roughness requirement varies according to the speed limit. For speed limits greater than 45 in./mi. and less than 45 in./mi., the maximum allowable IRI value for localized roughness is 190 and 250 in./mi., respectively. For a location over an expansion joint, the maximum allowable IRI value for localized roughness is 350 in./mi. for both cases. • Utah DOT: The maximum allowable IRI value for localized roughness is 250 in./mi. and only applies if the length over which the IRI is more than 250 in./mi. exceeds 15 ft. More details about the procedures used by Utah DOT are presented in Chapter 4, which describes case examples. Pay Adjustments for Smoothness Table 8 summarizes the pay adjustment practices used by state DOTs. Ohio DOT and Utah DOT are the only state DOTs that use positive and negative pay adjustments. Details about the pay adjustments that are used by the Ohio and Utah DOTs are described in Chapter 4, which describes case examples. State DOT Pay Adjustment Practice Number of State DOTs Percentage of State DOTs (%) Alabama, Nevada Not used 2 25 Louisiana Positive pay adjustments only 1 12 Michigan, Minnesota, Tennessee Negative pay adjustments only 3 38 Ohio, Utah Positive and negative pay adjustments 2 25 Total 8 100 Note: Alabama DOT has used an IRI-based specification only on one project. Louisiana DOT only has a draft specification that has not been finalized and published. Table 8. Pay adjustment practices used by state DOTs – IRI-based specification.

State of the Practice 33   Although a state DOT may not have a negative pay adjustment, the contractor is required to correct the bridge surface to meet the MIRI or localized IRI criterion or both as applicable in the state DOT specification. The method of correction of the surface is specified in the smoothness specification, and typically involves grinding areas with bumps. Smoothness Evaluated from Profilograph Measurements Overview Eight state DOTs (20% of responding DOTs) have a profilograph-based smoothness specifi- cation for concrete bridge decks. These are the DOTs in Florida, Georgia, Hawaii, Illinois, Iowa, Mississippi, Nebraska, and South Carolina. Table 9 shows the methods used in these states to obtain the profilograph measurements. Four state DOTs (in Florida, Hawaii, Mississippi, and South Carolina) require the use of a California profilograph, while Nebraska DOT requires the use of a modified California profilograph, which is 12 ft. in length, compared to the California profilograph, which is 25 ft. long. Illinois DOT requires a California profilograph simulation to be performed on the data collected with an inertial profiler, while Georgia DOT requires a Rainhart profilograph simulation to be performed on the data collected with a lightweight inertial profiler. Iowa DOT allows data to be collected with a California profilograph, or a California profilograph simulation to be performed on the data collected with an inertial profiler. Limits of Application of Smoothness Specification The limits over which the smoothness specification is applied (i.e., bridge deck only; bridge deck and approach slabs; bridge deck, approach slabs, and a specified length of pavement before the entry approach slab and after the exit approach slab) varied among the state DOTs. Table 10 shows the limits over which the profilograph-based smoothness specification was applied. In Iowa, the approach slab is referred to as the bridge approach and is treated separately from the bridge deck, where PI values are computed separately for the bridge deck and the bridge approach. Functional Class of Highway on which the Bridge is Located All state DOTs that have a profilograph-based smoothness specification indicated the smoothness specification is applicable to all functional classes of highways on which the bridge is located. Illinois DOT indicated the profilograph-based smoothness specification only applies for bridges that are diamond ground after construction. As the grinding process can remove up Method of Obtaining Profilograph Data State DOT Number of State DOTs Percentage of State DOTs (%) California Profilograph Florida, Hawaii, Mississippi, South Carolina 4 50 Modified California Profilograph Nebraska 1 12.5 California Profilograph Simulation on Inertial Profiler Data Illinois 1 12.5 California Profilograph or California Profilograph Simulation on Inertial Profiler Data Iowa 1 12.5 Rainhart Profilograph Simulation on Inertial Profiler Data Georgia 1 12.5 Total 8 100 Table 9. Method of obtaining profilograph data.

34 Practices for Ensuring the Smoothness of Concrete Bridge Decks to ¼ in. from the concrete surface, the bridge deck is constructed ¼ in. thicker. The smoothness of other bridges in Illinois are checked using a straightedge. Minimum Length of Bridge for Application of Smoothness Specification Table 11 shows the minimum length of bridge for using a profilograph-based smoothness specification. As shown in Table 11, four state DOTs have a minimum length requirement for bridges for using a profilograph-based smoothness specification. In these states, smoothness is evaluated using a straightedge when profilograph measurements are not obtained. In Iowa, the minimum length for the bridge and the approach slabs for computing the PI is 100 ft., but the bump requirement is applicable for bridges and approaches slabs of any length. Smoothness Data Collection Profilograph data along the two wheelpaths in each travel lane are required for the computation of PI as well as for detecting bumps. Table 12 shows the party that is responsible for collecting the profilograph data in each state. In Mississippi and Florida, where data collection is performed by a third party hired by the con- tractor and the contractor respectively, the data collection is monitored by the DOT. In Illinois and Iowa, where data collection is performed by the contractor, verification testing of the contractor-collected data is performed by the DOT. No time frame for collecting the data after the bridge is constructed is specified by six state DOTs (those in Florida, Georgia, Illinois, Mississippi, Nebraska, and South Carolina). Hawaii DOT requires data collection to be completed within 14 days after construction. In Iowa, for bridge decks that are less than 100 ft. long, and when the bridge deck is constructed in a single pour, the contractor must provide the DOT the results from testing within 14 days after construc- tion. For decks that are more than 100 ft. long, and which are not constructed in a single pour, the State DOT Limits of Application of Smoothness Specification Number of State DOTs Percentage of State DOTs (%) Mississippi Bridge deck only 1 12 Florida, Georgia, Hawaii, Iowa, Nebraska, South Carolina Bridge deck and approach slabs 6 76 Illinois Bridge deck, approach slab, and a specified distance of pavement before the entry approach slab and after the exit approach slab 1 12 Total 8 100 Table 10. Limits of application of the profilograph-based specification. State DOT Minimum Length of Bridge (ft.) Number of State DOTs Percentage of State DOTs (%) Florida, South Carolina 100 2 25 Illinois 150 1 12.5 Georgia 528 1 12.5 Hawaii, Iowa, Mississippi, Nebraska No minimum 4 50 Total 8 100 Table 11. Minimum length of bridge for using a profilograph-based smoothness specification.

State of the Practice 35   results of the testing for the first pour must be provided to the DOT within 5 days. On subsequent placements, the contractor is required to provide the DOT results for every third placement. Interval for Reporting the Profile Index Some state DOTs require PI to be reported for the entire lane of the bridge for each lane, while others require PI to be reported at specified length intervals for each lane. Table 13 shows the interval over which the PI must be reported for each state DOT. Blanking Band and Profile Index Values Table 14 shows the blanking band value used by each state DOT and the maximum allow- able PI values. The blanking bands used by the DOTs were zero, 0.1 in., or 0.2 in. Three state DOTs each use a zero blanking band and a 0.2-in. wide blanking band, with two state DOTs using a 0.1-in. wide blanking band. As seen in Table 14, the maximum allowable PI values are higher for the state DOTs that use a zero-blanking band, when compared to the state DOTs that use a 0.1- or 0.2-in. blanking band. This is because when a 0.1- or a 0.2-in. blanking band is used, a certain part of the profilograph trace is covered by the blanking band and therefore fewer scallops that protrude outside of the blanking band are seen, which results in a lower PI. Bump Criterion The bump criterion that is used by the state DOTs to detect bumps is shown in Table 15. This table shows the chord length that is used to detect bumps as well as the maximum limit for bumps above which correction is required. One state DOT (Hawaii DOT) does not have a bump criterion. For the state DOTs that have a bump criterion, the chord length used is 25 ft., except for Nebraska DOT, which has a chord length of 12 ft. As described previously, the length State DOT Party Responsible for Data Collection Number of State DOTs Percentage of State DOTs (%) Georgia, Hawaii, Nebraska, South Carolina DOT 4 50 Florida, Illinois, Iowa Contractor constructing the bridge 3 38 Mississippi Third party hired by contractor constructing the bridge 1 12 Total 8 100 Table 12. Party responsible for data collection – profilograph-based smoothness specification. State DOT PI Reporting Intervals Number of State DOTs Percentage of Responding State DOTs (%) Georgia, Illinois, Mississippi Entire Lane 3 38 Hawaii, Nebraska 100 ft. 2 25 Florida, South Carolina 300 ft. 2 25 Iowa Entire Lane or 0.1 mi. 1 12 Total 8 100 Note: For Iowa, PI is reported for the entire lane of the bridge if the bridge is 778 ft. or less. If the bridge is more than 778 ft. long, the PI is reported at 0.1-mi. intervals. Table 13. Interval for reporting Profile Index.

36 Practices for Ensuring the Smoothness of Concrete Bridge Decks of the profilograph specified by all state DOTs is 25 ft., except for Nebraska DOT, which uses a profilograph 12 ft. long. Pay Adjustments for Smoothness Out of the eight state DOTs that use a profilograph-based smoothness specification, no posi- tive or negative pay adjustments are applied based on the obtained PI values by seven state DOTs. Iowa DOT uses positive or negative pay adjustments, and the PI values obtained after corrective action has been performed are used for pay adjustments. Storage of Roughness Data of Bridges and the Use of the Data Storage of Roughness Data on Bridges State DOTs collect profile data on their highway system during network-level data collection using an inertial profiler, and then use these data to compute the IRI of pavement segments, which is stored in a PMS. The inertial profiler travels over bridges during data collection of the highway system and collects the profile data on the bridges. The number of state DOTs that indicated they store or do not store the IRI data on bridges computed from the profile data collected during the network level survey of their highway system is shown in Table 16. Of the 10 state DOTs that indicated they store the IRI data of bridges, nine indicated they store the IRI of the bridge deck and the approach slabs, while one state DOT indicated it stores the IRI of the bridge deck only. State DOT Width of Blanking Band (in.) Maximum Allowable PI (in./mi.) Florida 0.2 10 Georgia 0.1 15 Hawaii 0.1 10 Iowa Zero 22.1 Illinois Zero 25 Mississippi Zero 65 Nebraska 0.2 0.5 South Carolina 0.2 10 Note: For Iowa, PI values are computed separately for the bridge deck and bridge approach, and the requirement is applicable to both the bridge deck and the approach slabs. Table 14. Blanking band width and maximum allowable PI values used by state DOTs. State Limit for Bumps (in.) Chord Length for Detecting Bumps (ft.) Florida, Illinois, Mississippi 0.3 25 Georgia 0.2 25 Hawaii No Criterion Not Applicable Iowa 0.5 25 Nebraska 0.15 12 South Carolina 0.25 25 Table 15. Bump criterion and chord length used to detect bumps.

State of the Practice 37   Evaluation of the Roughness Progression of Bridge Decks All state DOTs that store the IRI data of bridges indicated they do not use the IRI data to evaluate the roughness progression of bridges over time. Use of Roughness Data in Decision Trees for Managing Bridges Of the 10 state DOTs that store IRI data on bridges, one state DOT (Ohio DOT) indicated the decision tree for managing bridges triggers a treatment based on the roughness level of the bridge deck. Maintenance and Rehabilitation Activities to Address Roughness of Bridges Schedule for Performing Maintenance Activities that Affect Ride Quality The responses from the state DOTs on whether they have a schedule for performing mainte- nance activities on bridges that affect ride quality (e.g., inspecting expansion joints and approach slabs and repairing if issues are found, and applying surface treatments) are shown in Table 17. Type of Maintenance or Rehabilitation Activities Performed to Maintain Smoothness In the survey, the state DOTs were asked to select the type of maintenance or rehabilitation activities typically performed on bridges to maintain smoothness from the following list: • Repairing expansion joints. • Repairing distress in approach slabs. Description Number of State DOTs Percentage of Responding State DOTs (%) IRI data of bridges stored 10 26 IRI data of bridges not stored 28 74 Total 38a 100 aOne DOT did not respond to this question. Table 16. Storage of IRI data in a pavement or bridge management system. Description Number of State DOTs Percentage of Responding State DOTs (%) DOT has a schedule for performing maintenance activities 4 10 DOT does not have a schedule for performing maintenance activities 32 82 Not known 3 8 Total 39 100 Table 17. Schedule for performing maintenance activities on bridges that affect ride quality.

38 Practices for Ensuring the Smoothness of Concrete Bridge Decks • Placing an AC overlay. • Placing a concrete overlay. • Placing a polymer overlay. Each respondent could select one or more of the items from the list. The number of responses received for each of the categories is presented in Table 18. Several state DOTs indicated they do not specifically perform maintenance activities to main- tain the smoothness of the bridge deck, and that maintenance activities are performed to pre- serve the bridge deck. Funding Mechanisms for Ensuring a Smooth Riding Surface on Bridges Table 19 summarizes the responses from the state DOTs on funding mechanisms that are used for bridge preservation to ensure that bridges provide a smooth riding surface (e.g., the repair of expansion joints or the repair of approach slabs). A few of the respondents indicated that dedicated funding is provided for bridge preservation, but these funds are not specifically provided to ensure the smoothness of the bridge. Response Number of State DOTs Percentage of Responding State DOTs (%) Dedicated funding provided annually to address smoothness-related issues for a specified length of bridges 4 10 Dedicated funding provided annually to address smoothness-related issues on a specified number of bridges 0 0 No dedicated funding is provided, and issues are addressed when they are reported 24 62 Unknown 11 28 Total 39 100 Table 19. Funding mechanisms for ensuring a smooth riding surface on bridges. Activity Number of Responses Percentage of Response (%) Repairing expansion joints 31 27 Repairing distress in approach slabs 26 23 Placing an AC overlay 21 18 Placing a concrete overlay 17 15 Placing a polymer overlay 19 17 Total 114 100 Table 18. Maintenance/rehabilitation activities performed on bridge decks.