Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 3: Coding and Marking Guidelines (2016)

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This part of the field manual provides background information helpful for performing evaluations of highway structures during emergency situations. The chapters comprising the background are the introduction, the overview of highway structure safety evaluation, the Preliminary Damage Assessment guidelines, and an overview of emergency events. These chapters should be reviewed prior to conducting evaluations of highway structures. P A R T I Background

Part I: Background 3 Introduction 1 Introduction 1.1 Purpose and Scope This report volume is a field reference manual to be used for assessing, coding, and mark- ing of highway structures during emergency situations. Highway structures include bridges, tunnels, culverts, walls, embankments, and overhead signs. These assessments are made to determine whether damaged, or potentially damaged, highway structures are safe for contin- ued use, or if their use should be restricted or prohibited. Coding and marking follows the assessment process to clearly communicate within and between agencies. This manual is intended to be used primarily by Preliminary Damage Assessment responders. This can include inspectors, bridge engineers, structural engineers, maintenance personnel, and others involved in highway structure inspections during emergency situations. Many of those needed for emergency assessments will likely not be regularly involved in routine inspections, especially for larger events. The intent is to have a uniform process, regardless of the experience level of the Preliminary Damage Assessment responder. These guidelines are focused on providing information needed for rapid yet reliable field assessments of highway structures in emergency situations. Advice is provided to assess damage states of specific elements for each type of highway structure being considered. The basic approach is to provide guidance on where to look for damage, give advice on how to rate the safety of the structures, and document the different degrees of damage found. Guidelines are also provided on how to code and mark the structures after assessment. These include inspection forms and placard templates for physical marking on the structure as well as digital coding and marking procedures. For each type of structure, the basic ele- ments that need to be examined in order to determine the overall structural rating are listed. More detailed information on the overall process for assessing, coding, and marking of highway structures in emergency situations can be found in the companion reference manual to this document. The reference manual is intended for a management audience; however, it may also be helpful to the Preliminary Damage Assessment responders to understand their role in the overall process. 1.2 Organization of the Manual This manual contains three main parts as well as several appendices. Part I (Chapters 1 through 4) presents background information, including an overview of the assessment pro- cedure, Preliminary Damage Assessment procedures and technologies, and an overview of

Part I: Background 4 Introduction emergency events. Part II (Chapters 5 through 9) provides Preliminary Damage Assessment procedures for the different highway structures. For each structure, damage states are discussed and assessment forms are presented. In Part III (Chapters 10 to 15), example damage photos along with classification in terms of level of damage are provided as visual aids for responders and inspectors. Finally, five appendices are presented. These contain suggested Preliminary Damage Assessment equipment lists; field safety considerations; contact list templates; an emergency route template useful in emergency events situations, including pre-event plan- ning; and an example completed assessment form. 1.3 Definitions of Key Terms 1.3.1 Assessment Stages The main types of inspections that will be conducted range from fast overview assessments to slower, more detailed assessments. Refer to Section 2.1 for more detailed definitions. • Fast Reconnaissance (FR)—Provides an overview to establish the extent of the damage region immediately following an emergency event. • Preliminary Damage Assessment (PDA)—An assessment performed for each structure immediately after an event, preferably within hours, to provide information on the status of the structure and to determine whether subsequent assessment stages will be needed. This stage is typically conducted by PDA responders (PDARs). • Detailed Damage Assessment (DDA)—Provides an evaluation of structural damage and decisions on use restriction after the PDA. This stage is typically conducted by specialists (e.g., structural, geotechnical, hydrological, mechanical, and material engineers). • Extended Investigation (EI)—An in-depth inspection that requires specialized technolo- gies. This stage is typically performed after an UNSAFE rating from the DDA stage to determine how to repair or replace the structure. 1.3.2 Element Damage Rating One of the following ratings is given to each element by a PDAR based on the amount of damage visually observed: • None—The element shows no signs of damage. • Minor—The element shows cosmetic or non-structural damage. • Moderate—The element has experienced some structural or geotechnical damage. • Severe—The element is significantly damaged and cannot function properly. Refer to Section 3.3 for more detailed definitions.

Part I: Background 5 Introduction 1.3.3 Marking Classifications A final marking classification shall be assigned to each structure indicating appropriate usage during and following an emergency event. Refer to Section 2.3 for more detailed definitions. • INSPECTED—This classification is denoted by a green color which indicates that no apparent damage was found and the structure can function without further evaluation. • LIMITED USE—This classification is denoted by a yellow color and indicates that minor to moderate damage conditions were observed or are believed to be present. The structure requires further evaluation but can still be used for restricted traffic. • UNSAFE—This classification is denoted by a red color and indicates the structure has experienced severe damage or collapse and cannot function properly under traffic loads. 1.3.4 Emergency Management Roles The following roles are defined: • Managing Engineer (ME)—The ME is the key lead for making all structural assessment decisions regarding highway structures. • Chief (Structural, Geotechnical, Hydrological, Mechanical, Materials) Engineer—This role is reserved for the engineer who will coordinate specialty inspectors including structural, geotechnical, hydrological, mechanical, and materials. • PDA Responder—A PDAR is an individual who will perform PDA evaluations following an emergency event. For a Level I response, PDARs will typically be routine inspectors. For higher response levels, PDARs can be trained emergency responders (e.g., maintenance and operations crews, and design engineers).

Part I: Background 6 Overview of Highway Structure Safety Evaluation 2 Overview of Highway Structure Safety Evaluation 2.1 Assessment Stages The four distinct procedures that can be performed in the assessment of highway structures during emergency situations are briefly described in the following list; an estimated inspec- tion time per highway structure is also provided. • Fast Reconnaissance (within 4 to 6 hours)—The objective of the FR assessment stage is to provide an overview and to establish/update the extents of the damage region as necessary. This work can be completed both in the office and in the field. While FR should be com- pleted at all response levels, the type and detail of FR will depend heavily on the size of the event. • Preliminary Damage Assessment (typically 10 to 30 minutes per highway structure)— This assessment stage is performed immediately following an incident, likely within hours, to provide information on the need for action such as closures or restricted use and to define immediate remedial action if needed. This stage is the focus of this manual and can provide valuable information for the DDA stage. The onsite PDA will be conducted by PDARs. • Detailed Damage Assessment (typically 1 to 2 hours per highway structure)—The DDA stage is performed as soon as possible following an UNSAFE rating from a PDA, likely within 8 hours of the incident, if needed, and will continue as necessary to provide an evaluation of structural damage level and decisions on use restriction, or the need for an EI. This is a “Damage Inspection” as defined by the Manual for Bridge Evaluation (MBE) and is not considered a rapid assessment for an emergency situation. It is therefore beyond the scope of these guidelines. • Extended Investigation (following the DDA)—The EI stage is performed as soon as pos- sible following an UNSAFE or LIMITED USE rating from a DDA. This is an “In-Depth Inspection” as defined by the MBE and may also include a “Special Inspection” or an “Underwater Inspection.” The EI is not considered a rapid assessment for an emergency situation and is therefore beyond the scope of these guidelines. Each procedure is used for a specific purpose and should be performed by the appropriate personnel (see Table 2-1). Figure 2-1 diagrams the assessment stages.

Part I: Background 7 Overview of Highway Structure Safety Evaluation 2.2 Response Levels Response levels relate to the immediacy of the needed response, and the level of resources/ effort that will be needed during an emergency event. Actions associated with response levels are initiated when the ME has determined that it is safe to begin. The four response levels are as follows: Level I Routine inspectors in the affected region(s) are placed on call to perform PDA. Teams are mobilized when the ME determines that some damage has occurred based on FR observations. Level II State highway agencies (SHAs) complete PDAs with their maintenance crews and DDAs using inspection crews. Additional personnel such as design engi- neers are placed on call and mobilized to assist with PDAs when the ME deems appropriate. Level III Inspectors focus directly on DDAs, while maintenance crews, design engineers, and others (as needed) in the region are immediately mobilized to perform PDAs. Inspectors from other regions could be placed on call to assist. External consul- tants from local firms who are appropriately trained could be utilized, as necessary. Federal assistance and coordination may also be required. Level IV In addition to the mobilization strategy in III, the SHA requests immediate assis- tance from inspectors, maintenance crews, design engineers, and external con- sultants from other regions to assist with the PDAs. Significant federal assistance and coordination will be necessary. Table 2-1. Highway structure assessment methods. Method Suggested Personnel Objective Fast Reconnaissance Chief engineers or managing engineer in aircraft or vehicle; specialized technicians as needed; the public Determine the geographic extent of damage, identify impassable routes and collapsed structures, and suggest priority for site assessments. Preliminary Damage Assessment PDARs—Trained emergency responders (maintenance & operations crews, design engineers) Determine the extent and type of damage to each structure, close unsafe structures, code and mark, and recommend DDA if needed. Detailed Damage Assessment Trained inspectors Provide recommendations for restriction, repairs, or further investigation; code and mark as necessary; close unsafe structures; reopen structures deemed safe that were closed; and provide a damage level estimate. Extended Investigation Specialists (e.g., structural, geotechnical, hydrological, mechanical, materials) Provide specific recommendations on necessary restrictions and/or repair, detailed damage analysis, and approximate cost estimate for remedial work.

Part I: Background 8 O verview of H ighw ay Structure Safety Evaluation PDA LIMITED USE UNSAFE DDA UNSAFE INSPECTED EI Repair/ Rebuild INSPECTED UNSAFE (Partial/Full Collapse) Emergency Situation Primary Scope of NCHRP Project INSPECTED Preparation UNSAFE = The structure requires further evaluation in the next assessment stage prior to being open to traffic. LIMITED USE = Potentially dangerous conditions are believed to be present and usage is restricted to ensure public safety. INSPECTED = The structure appears to be in the same condition as it was prior to the event. No Collapse FR Figure 2-1. Assessment stages and subsequent primary level of coding.

Part I: Background 9 Overview of Highway Structure Safety Evaluation 2.3 Coding and Marking System A coding and marking system was developed to support uniform communication between inspectors, maintenance crews, engineers, and others as necessary. All inspected structures within the affected region should be marked both physically (in the PDA phase) and digitally (in the FR and PDA phases) after conducting an assessment and establishing the coding for the structures. Structures shall be marked physically in an obvious location on both ends of major ele- ments of the structure using placards affixed with a color decal with the coding option (see Figure 2-2 for the placard and Figure 2-3 for the coding options). For example, the placard with decal would be on the right-hand side of the approach to the bridge (i.e., on railings or fixed structural elements at both bridge abutments). These marking placards and decals should be available at all offices and in the inspection vehicles. Structures shall be marked digitally in a central database and/or geographical information system (GIS) map that is accessible to authorized staff with a secure connection. The use of quick-response (QR) codes on the placard in concert with smart devices (i.e., smartphones or tablets) or standalone readers can significantly reduce coding time and improve informa- tion flow and reliability between personnel and across agencies. PDARs should have a decal/ sticker with a QR code or have access to a mobile QR code printing machine. The marking (and hence contents of the QR codes) must clearly indicate the agency that made the marking, the assessment stage (i.e., PDA or DDA), the date and time of the assess- ment, the resultant coding (i.e., INSPECTED, LIMITED USE, UNSAFE), actions taken (i.e., close structure, close lane), and name/initials of the inspectors. After undergoing PDA, highway structures should be marked with one of two placards: INSPECTED or UNSAFE (refer to Figure 2-1). If a structure is marked UNSAFE during a Figure 2-2. Example marking placard.

Part I: Background 10 Overview of Highway Structure Safety Evaluation PDA, it will be further evaluated using DDA. During DDA, highway structures are marked with one of three decals on a new/updated placard: INSPECTED, LIMITED USE, or UNSAFE (refer to Figure 2-1). This marking lets the SHAs, responders, inspectors, and the public know the condition of the structure as well as the date and time the assessment was per- formed. The system used for marking a highway structure and the definition of each marking category are summarized in Table 2-2. In addition to marking a highway structure, it may be necessary to designate restricted use of certain parts of the structure that may be hazardous areas. For example, if a bridge deck is badly cracked or raised on one side, traffic could be redirected onto the non-damaged por- tion of the bridge. 2.3.1 Marking and Barricading Procedures After the assessment of a highway structure has been completed, the structure should be marked using the following procedures and criteria: 1. Place the appropriate placard in a clearly visible location near the entrance on the right side of the structure (e.g., right side of a bridge approach or railing, right side of a tunnel entrance). Figure 2-3. Marking codes for PDA (left) and DDA (right).

Part I: Background 11 Overview of Highway Structure Safety Evaluation 2. Affix the placard using metal clips or wire. If not available, use durable tape, plastic ties, or any other reliable method. 3. If the structure was marked as UNSAFE, determine the appropriate barricading tech- niques from the following list: a. Physically park vehicles across both road approaches and arrange for someone to standby at both ends of the structure. b. Call the district to arrange for barricades and cordoning off structures. If necessary, cordoning should include personnel for monitoring the barricades at all times. c. If it is a critical structure, notify the policing agencies and general public via public safety announcements on commercial radio and television stations. d. Other techniques as recommended by the district. 2.3.2 Changing a Coding/Marking There may be a need to change the coding and marking of a highway structure. This can result from several possible situations: • A DDA following an initial PDA • An EI • Reinspection to verify or correct an existing marking • Reinspection after another emergency event • Reinspection after temporary repairs have been made • Reinspection after removal of finishes to expose concealed conditions Any change in coding and marking category must be done by an authorized representative of the agency in charge of that particular highway structure. Table 2-2. Highway structure coding and marking classifications. Marking Classification Description INSPECTED (Green) This classification utilizes a green color code and indicates that subject to the inspection at the current stage, no apparent damage was found and the original load carrying capabilities of the structure appear to be fully intact. No restrictions on use. LIMITED USE (Yellow) This classification utilizes a yellow color code and indicates that dangerous conditions are believed to be present. Usage is restricted to ensure public safety. The restrictions to use must be clearly defined by symbols and can include lane closures, vehicle load limits, or use by emergency vehicles only. UNSAFE (Red) This classification utilizes a red color code and indicates that extreme hazards are present, the structure is in imminent danger of collapse, or the structure has collapsed. The structure is closed to all traffic.

Part I: Background 12 Overview of Highway Structure Safety Evaluation 2.4 Use of Judgment Required The use of judgment is essential in the assessment of damaged highway structures, both for personal safety as well as safety of the general public. This section will address both of these. All personnel should have adequate training and should have been briefed on the contents of these guidelines through an annual highway structures inspection safety seminar before performing damage assessments. PDARs are then responsible for their safety under possibly extreme conditions as a consequence of the emergency event. PDARs should only proceed if they are confident their actions do not pose a risk to themselves or others. PDARs should use best judgment to ensure they are safe and aware of their surroundings at all times. Not every dangerous situation that may be encountered is covered by the guidelines and procedures provided herein. The use of judgment is essential in the assessment of damaged highway structures. In most cases, the type and nature of the damage will not easily fit into a checked box or match the sample images. The materials in this manual are meant to help in making a determination, but ultimately judgment should prevail. For those situations where no guidance beyond this manual has been provided, or if the guidance furnished is not appropriate for the emergency situation, the PDAR team must rely on their collective experience and judgment. When necessary, obtain additional help from a superior and/or request a DDA.

Part I: Background 13 Preliminary Damage Assessment 3 Preliminary Damage Assessment Each PDA team will be assigned to a route with a list of structures to assess. Due to the unpredictable nature of emergency events, it is important to be flexible as changes to planned routes may occur as more information becomes available. This flexibility will ensure that the highest priority structures are addressed first. 3.1 PDA Strategy The objective of PDA is to quickly inspect and assess highway structures in the damaged area that were determined to be at risk from the FR stage. It is performed by evaluating dam- age on a highway structure according to the PDA procedure listed below. Each highway struc- ture should be evaluated in its entirety as well as by looking at system elements. PDA should only result in a structure being coded/marked as INSPECTED or UNSAFE. PDA evaluations should be performed by teams of two PDARs. Members of PDA teams should independently make a coding/marking decision regarding the highway structure and then jointly review their decisions. In doubtful situations, the use of judgment is required. In particular, highway structure elements with moderate damage can be difficult to assess, espe- cially during a PDA. When there is uncertainty about coding/marking a structure UNSAFE, consider coding/marking it UNSAFE and request a DDA. To be conservative, in the event one PDAR decides to code/mark as INSPECTED and the other UNSAFE, the structure should be coded/marked as UNSAFE and a DDA requested. If a highway structure is found to have minor or no damage (i.e., non-structural damage), and if there are no other hazards or unsafe conditions present, it should be deemed as being safe and it can be coded/marked as INSPECTED. If a highway structure or element is found to be moderately to critically damaged, or if more severe damage (i.e., partial collapse) is imminent, it should be coded/marked as UNSAFE. 3.2 Conservative vs. Unconservative Assessments Conservative coding and markings are those in which there is some doubt on the structural integrity of the highway structure. If it is not clear that the structure is safe for traffic in any way, it should be marked conservatively as UNSAFE. Highly conservative markings should be considered for highway structures that are critical links in the transportation network and those that have a high consequence of failure (e.g., incurring life losses). Factors that influ- ence these structures include operational classifications, level of traffic, detour availability,

Part I: Background 14 Preliminary Damage Assessment and lifeline route designation. Although these structures should be opened as soon as possible to the public, in the event of any questionable damage, they should be marked as UNSAFE. It should also be noted that PDARs should be more conservative with regards to high-risk highway structures such as bridges and tunnels. Other structures such as walls and overhead signs may not pose as much risk as a bridge or tunnel collapse; therefore, reduced conserva- tivism in the assessment/coding/marking procedures can be applied. However, some conser- vatism is always important because of information incompleteness, visibility limitation from debris, potential human errors, and uncertainties in the available information. Less conservative markings are reserved for highway structures that do not pose an imme- diate threat to the transportation network. If a highway structure is moderately damaged but does not pose a threat to the traveling public, it may be marked as INSPECTED with low- priority DDA checked on the assessment form. 3.3 Element Damage Levels Prior to coding and marking the overall structure, the PDARs should quickly assess the state of individual elements. This is useful information for load rating analyses at the DDA stage as well as for tracking the amount of damage for loss estimates. This section provides definitions for the individual element ratings for each highway struc- ture. It should be noted that these damage levels are separate from the final decision for over- all coding and marking of the structure as either INSPECTED or UNSAFE. These damage levels are specific to basic structure elements and are used to provide information for repair, prioritization, and subsequent assessment procedures. These damage levels are marked in the inspection forms. For each highway structure, a list of common elements is provided in this manual. These elements should be reviewed independently and coded using Table 3-1. Each highway struc- ture has different elements corresponding with a damage level to be used for reference. When the condition of an element is not clear, it should be coded conservatively. It should be noted that some damage (e.g., corrosion) may be a result of structure degra- dation. These damages are likely not a result of an emergency event. However, they are still Table 3-1. Element damage level descriptions. Damage Level Description None (Green) The element and/or structure show little to no signs of damage. Minor (Yellow) The element shows signs of cosmetic or non-structural damage that has little to no effect on the system integrity. Structure appears capable to carry traffic. Moderate (Orange) The element has experienced structural or geotechnical damage that may affect the system integrity. Severe (Red) The element is damaged where it cannot function properly. Element may be in danger of collapse. If any element is marked as severe, the structure should be marked as UNSAFE.

Part I: Background 15 Preliminary Damage Assessment worth noting during PDA as they may result in the structure being weakened. Such damage should also be considered when making a final call for the structure posting (INSPECTED or UNSAFE). Upon coding the individual elements, an overall marking will be decided for the structure. When elements are coded as minor or moderate, the overall marking is less clear. A conserva- tive judgment should be used when making the final marking decision. If a structural element (e.g., bridge columns, bearings, or wingwall; tunnel deck; overhead sign column support) receives a moderate damage level rating, the structure should be marked as UNSAFE. If a non- structural element (e.g., bridge parapet, tunnel railing, and overhead sign catwalk) receives a moderate damage level ranking, the structure may be marked as INSPECTED, if there is no other structural damage, although precautions and cordoning off the affected areas should be done to ensure safety and to make sure users are aware that there is a safety hazard. 3.4 PDA Procedure The following list outlines the steps for the PDA procedure: 1. Upon receiving notification of an emergency event, PDARs review Chapter 4 for a list of likely damages for highway structures. 2. PDARs assist in rescue efforts, if necessary. 3. If any hazardous condition is encountered during the inspection, such as downed power lines, faulty traffic control devices, or roadway obstructions, the appropriate authorities should be contacted in order to secure the area. 4. Prior to starting PDA, PDARs confirm with each team member the division of tasks. Generally, only one team member should fill out a single form for each structure. Both should make observations and be alert to the conditions of the scene. 5. PDARs approach the structure with caution and never walk or drive immediately under, over, or adjacent to the structure until the safety of the environment has been assessed. 6. Each PDAR (each team should have at least two people) should remain reasonably sepa- rated from each other but remain within visible range at the same time and never go underneath a structure at the same time. 7. When first arriving to a structure site, take a photograph of the identification tag, a photo- graph of the overall structure, and obtain geographic positioning system (GPS) coordinates. If available on the structure, the QR code should be scanned. With a smart device and app, these activities can be completed from the same device. 8. A site visit is estimated to take 15 to 30 minutes to complete. However, if the structure is clearly collapsed and unsafe, PDARs can simply complete the basic elements of the form and move onto the next site after notifying the ME that the structure should be closed. PDARs should be conscious of the time and make sure that they do not spend too long at a particular site so they can efficiently move through their route. 9. A more detailed process for each structure is written in Part II to help quickly walk PDARs through the process. When necessary, PDARs should consult the damage state lists and photographic examples provided in Part III to aid in damage state ratings.

Part I: Background 16 Preliminary Damage Assessment 10. PDARs look for evidence of disturbance or irregularities—such as shifts in guardrails or striping—and note these on the form. 11. PDARs provide an element damage level rating (none, minor, moderate, severe) for all applicable elements of the structure (Section 3.3). 12. Once PDA inspection is complete, the PDAR team meets and comes to a conclusion on the overall marking of the structure (INSPECTED or UNSAFE). 13. PDARs fix the placard to the structure in the appropriate location (refer to Section 2.3.1 for suggested procedures). The outcomes of this procedure are both an overall coding for the structure as well as coding of individual elements. Completing the forms can be efficiently carried out using a smart app running on a smart device. The smart app should include assessment forms, making filling out the form while assessing a structure easier. The smart app can contain existing database information for the structure directly on the device or can access it in the cloud. When communication links are available, the data in the completed form can be transmitted in real time back to the central command. When these communication links are not available on site, the PDAR can send the data when returning to a suitable area. At a minimum, the smart app should include the following: • This manual with keyword search capabilities. • Digital forms of the element damage levels, including links to sample photo pictures of each level of damage for different structural elements. • Digital forms of the damage matrix (Section 4.2), wherein each decision tab is digitally linked to the element damage level description and the sample photographs. • Access to the geospatial location of the structure and geospatial route for all structures to be inspected. • Access to the SHA’s structure inventory database. • Ability to read QR codes on existing placards and digital links to the database. • Photo capture and geo-tagging that automatically forms imagery metadata for evidence archival for the structure (or an element of the structure). • Ability to annotate photographs. Full details and templates for key components of a smart app can be found in NCHRP Web-Only Document 223: Guidelines for Development of Smart Apps for Assessing, Coding, and Marking Highway Structures in Emergency Situations. 3.5 Filling out Placards and Assessment Forms Placards and PDA forms should be filled out with the following considerations: 1. Provide information in all applicable fields on the inspection form. If an item is not known during the PDA, leave the field blank. When using a smart app, many fields can be filled automatically through a geo-referenced direct link to the database.

Part I: Background 17 Preliminary Damage Assessment 2. When element damages are not clear, provide comments that supply sufficient informa- tion to understand the observed damage state. 3. When making a recommendation for DDA priority following an UNSAFE rating, provide reasoning for low-priority or high-priority DDA evaluations. 4. If there is any damage that is particularly unique and not covered in the element damage levels, provide comments and/or sketches. 5. For the sake of time, do not draw sketches for every type of damage on a structure. Instead, focus on the moderate to severe damages that will provide better information for the DDA stage. Take photographs instead, when appropriate. 6. When physically marking a structure, write clear and legibly on the placard as this must be readable by inspectors performing subsequent inspections. 7. Assessment forms should be turned in as frequently as reasonable. At a minimum, reports should be turned in at the end of each day upon return from the field. For smart app users, forms can be completed and turned in continuously, provided Wi-Fi or network connec- tivity is available. If Wi-Fi is limited, reports can be uploaded during breaks and lunches at locations with Wi-Fi access. 8. In the event of an UNSAFE structure, contact the ME via call, text, or other communi- cation methods. UNSAFE structures should be reported immediately in order to avoid delays. It is vital that contact be made as soon as possible to ensure appropriate barricading and subsequent measures are taken. 3.5.1 Damage Summary The assessment form provides a space to indicate estimated percentage damage for the highway structure. This damage summary may help subsequent inspections with determin- ing the monetary and economic loss of a structure. The following guidelines provide exam- ples that may be used to estimate the damage summary of a structure. These examples do not cover all damage scenarios and ultimately the damage summary percentage should be decided based upon the PDARs’ collective experience and judgment. 1. None (0%)—No apparent structural or cosmetic damage is found. 2. Slight (0–1%)—Structure has slight cosmetic damage (e.g., broken concrete on a bridge railing, slight chipping of a tunnel wall, minor concrete spalling in an isolated area). 3. Light (1–10%)—Structure needs minor repairs (e.g., minor deck cracking on a bridge, tunnel roof with minor spalling, overhead sign with minor cracking). 4. Moderate (10–30%)—Structure is likely repairable with some structural damage (e.g., a few inches of expansion joint movement on a deck, spalling and section loss of tunnel walls, culvert with cracking around bolts). 5. Heavy (30–60%)—Structure is partially intact with multiple elements having structural damage. Structure may be salvageable (e.g., visible column shear cracks, extensive cracking of culvert, cracking of overhead sign post). 6. Major (60–100%)—Structure is in danger of collapse with several elements having severe damage. Repairs are unlikely (e.g., excessive sag of bridge deck, displacement of girder off

Part I: Background 18 Preliminary Damage Assessment bearing support, extensive cracking and spalling of culvert wingwall, very large column shear cracks propagating into concrete core). 7. Destroyed (100%)—Structure has failed completely and is unusable for traffic (e.g., deck unseating on a bridge, roof collapse of a tunnel, overhead sign tipped over). 3.6 PDA Technologies 3.6.1 Recommended PDA Technologies The onsite PDA will likely be conducted by PDARs who will use the recommended tech- nologies herein to generate structurally organized reports based on visual observations or equipment-based measurements (as time permits). Table 3-2 summarizes these technologies as well as their general availability annotations and resources. PDARs are strongly encouraged to use smart tablets for completing the assessment forms. In the worst case, PDARs should have paper-based copies of the forms that can be sent back to an office and logged digitally. Due to the potential for backlog and errors in transcription, paper-based forms should be used as a last resort. Recommended Technology General Availability Classification Available Resources Digital camera Commonly used No training needed Mobile imaging / video logging Commonly used No professional training needed Personal laptops / mobile computers Commonly used No professional training needed Personal communication devices Commonly used No professional training needed Smart devices that embed digital cameras, GPS, and communication Commonly used No professional training needed Personal GPS / Global Navigation Satellite System devices Commonly used No professional training needed Digital or paper maps Commonly used No professional training needed Cloth / tape measures / carpenter level / calipers / compass / level / laser distance measures and others Commonly used No professional training needed Signs / marking supplies and materials Commonly used No professional training needed Human visual inspection Commonly used NCHRP Research Report 833, Volume 3: Coding and Marking Guidelines Table 3-2. Recommended technologies for PDA.

Part I: Background 19 Preliminary Damage Assessment 3.6.2 Recommended Field Inspection Supplies for PDA Structures within a transportation network pose uncertain dangers to inspection person- nel, especially after a major event. PDA tools and equipment for inspection, protection, emer- gency protocols, and safety gear should be in place. Table 3-3 is a compressed list of recommended tools, gear, and materials (or “supplies” in general) for use in field inspection. When possible, these tools should be available in pre- packaged kits. Appendix A provides a checklist of all the items listed in Table 3-3 to be used during PDA evaluations. Inspection Equipment Clipboard Inspection forms 100’ measuring tape Flashlight Notepad 25’ pocket tape Red paint marker and ribbon Yellow paint marker and ribbon Green paint marker and ribbon Pens and pencils Hammer Keel/crayon Binoculars Cellular phone Flagging tape Duct tape Portable ladder Digital camera Pliers Micrometer Wire brush Chipping hammer Pocket knife Scraper Traffic control equipment Rope Shovel Boat* Waders* Underwater probe* Electronic and Communication Equipment State or local maps Laptop computer with charger Copies of latest structure inspection files Flash drives Identification badges Walkie-talkies or state-wide radio Traffic cones Satellite phone Safety Equipment Hard hat Work boots Safety vest Ear plugs Safety glasses Rubber boots Rain gear Work gloves Rubber gloves Dust mask Personal Supplies First aid kit Drinking water Toilet paper Food *Specialized PDAR teams for evaluating scour-critical structures Table 3-3. Recommended PDA tools and equipment.

Part I: Background 20 Overview of Emergency Events 4 Overview of Emergency Events 4.1 Overview This chapter provides an overview of common damages and possible modes of failure for each emergency event. These tables do not cover all types of damages expected. The emergency events covered are earthquake, tsunami, tornado, high winds, hurricane and storm surge, flooding, and fire. Damage types are classified as geotechnical, structural, hydraulic, or special case, indepen- dent of the highway structure type (see Table 4-1). Geotechnical damage involves the soil and foundations of the highway structures; structural damage includes the concrete, steel, timber, connections (or joints), and elements; hydraulic damage includes any water-related failures or consequences; and special cases include all damages that are not classified as one of the other three damage types. Table 4-1. Common damages/modes of failure. Damage Types Common Damages / Modes of Failure Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, and slope instability Erosion Bearing capacity failure Active or passive failure Foundation settlement Structural Cracking and spalling of reinforced concrete members Flexural and shear failures of reinforced concrete or steel members Buckling, fracture, and tension of steel members Fatigue damage, including low-cycle fatigue Inelastic deformation and buckling Hydraulic Scour Debris impact Inundation leading to hydrostatic and hydraulic pressures Washout Special Cases Thermal expansion Reduction of strength and material properties due to fire- induced thermal effects Efflorescence causing deterioration Decay of timber members Corrosion

Part I: Background 21 Overview of Emergency Events Table 4-2. Damage matrix in terms of emergency event types and highway structures. Structures Emergency Event Ea rth qu ak es Ts un am i To rn ad o an d H ig h W in ds H ur ric an e an d St or m Su rg e Fl oo di ng Sc ou r Fi re Bridges Tunnels Walls Culverts Embankments Overhead Signs Damage Scale Significant damage – Several collapses and irreparable damage to multiple structures across a large area. Moderate damage – Repairable damage to several structures. Minor damage – Localized damage to a few structures, most do not need significant repair. Damage unlikely. 4.2 Damage Matrix A two-dimensional matrix showing the expected level of damage to highway structures corresponding with emergency events is shown in Table 4-2. The main objective of this matrix is to provide a basis for prioritizing emergency response assessments of vulnerable highway structures. The four levels of damage are significant, moderate, minor, and unlikely. This table was developed based on the assumption that an emergency event has occurred that is significant enough to produce noticeable to significant damage to at least one structure of interest. However, it is possible that a structure could experience a higher level of damage at extreme intensities of an emergency event or when subjected to prolonged exposure. 4.3 Earthquake Earthquakes primarily cause damage through intense ground shaking. The intensity of an earthquake is measured by both the moment magnitude scale and the modified Mercalli scale; however, for damage assessment purposes, ground motion intensity measures are used to characterize the potential for damage. Common ground motion intensity measures include

Part I: Background 22 Overview of Emergency Events peak ground acceleration, peak ground velocity, and spectral acceleration. A list of common damages resulting from earthquakes is highlighted in Table 4-3. The majority of earthquake damage can be categorized as structural or geotechnical failures. 4.4 Tsunami The destructive force of a tsunami is measured by both the initial impact of a large wall of water hitting a coastline at great velocities and the overwhelming amount of water flowing off the land. Forces acting on structures created by tsunami waves are in the form of hydrostatic pressure, hydrodynamic pressure, impulsive forces, buoyancy, uplift, and debris-induced impact. Effects such as tsunami-induced liquefaction and foundation scour are also important to consider. A list of common damages resulting from tsunamis is highlighted in Table 4-4. Damage Types Common Damages / Modes of Failure Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, and slope instability Bearing capacity failure Active or passive failure Foundation settlement Structural Cracking and spalling of reinforced concrete members Flexural and shear failures of reinforced concrete or steel members Buckling, fracture, and tension failure of steel members Inelastic deformation and buckling Hydraulic Pipes bursting Special Cases Fire from utilities Table 4-3. Most likely earthquake damages. Damage Types Common Damages / Modes of Failure Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, and slope stability Erosion Structural Cracking and spalling of reinforced concrete members Buckling, fracture, and tension failure of steel members Fatigue damage, including low-cycle fatigue Inelastic deformation and buckling Hydraulic Scour Debris impact Blockage due to debris Inundation leading to hydrostatic and hydrodynamic pressures Washout Special Cases Corrosion Table 4-4. Most likely tsunami damages.

Part I: Background 23 Overview of Emergency Events 4.5 Tornado and High Winds One of the most damaging aspects of tornados in regard to highway structures is impact from debris. High speed winds can affect low weight structures such as overhead signs. High winds also have the potential to resonate the structure creating fatigue damage and loading. A list of common damages from tornado and high wind events is highlighted in Table 4-5. 4.6 Hurricane and Storm Surge Hurricanes cause damage primarily to aboveground structures. The primary factors that cause damage to highway structures are hydrostatic uplift, restraint failure, hydrodynamic uplift and lateral loading, debris effects, and scour. Hurricanes often result in extreme wind, heavy rainfall, and storm surge, which can amplify the amount of damage. Storm surge causes widespread damage to highway structures due to repetitive wave loading. Structures near the coastline may become submerged by the storm surge creating hydrostatic uplift and the potential for liquefaction and scour. A list of common damages resulting from hurricanes and storm surge is highlighted in Table 4-6. Damage Types Common Damages / Modes of Failure Structural Fatigue damage, including low-cycle fatigue Inelastic deformation and buckling Special Cases Flying debris Table 4-5. Most likely tornado and high wind damages. Damage Types Common Damages / Modes of Failure Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, and slope instability Erosion Structural Cracking and spalling of reinforced concrete members Buckling, fracture, and tension failure of steel members Fatigue damage, including low-cycle fatigue Inelastic deformation and buckling Hydraulic Scour Debris impact Blockage due to debris leading to flooding Inundation leading to hydrostatic and hydrodynamic pressures Washout Special Cases Corrosion Flying debris Table 4-6. Most likely hurricane and storm surge damages.

Part I: Background 24 Overview of Emergency Events 4.7 Flooding Flooding is generally divided into three load cases: hydrostatic loads, hydrodynamic loads, and impact loads. The hydrostatic loads are both vertical (buoyant) and lateral (pressures) and can cause unusual loading due to uplift and lateral forces. Hydrodynamic loads are caused by water flowing around the structure causing frontal impact loads, drag loads on the sides, and suction loads on the back. Impact loads can occur as a result of debris being carried by the flood and can be especially destructive. Table 4-7 lists common damages resulting from flooding. 4.8 Fire In concrete, the high temperature of fire causes chemical reactions as well as self-destruction stresses, which create cracks, spalling and deterioration of strength, and a loss in stiffness and ductility of the concrete as a material. Temperatures in excess of 400 degrees Celsius (752 degrees Fahrenheit) begin to reduce both the compressive strength of concrete and the yield strength of steel. Table 4-8 lists common damages from fire. Damage Types Common Damages / Modes of Failure Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, and slope instability Erosion Bearing capacity failure Active or passive failure Structural Inelastic deformation and buckling Hydraulic Scour Debris impact Blockage due to debris Inundation leading to hydrostatic and hydrodynamic pressures Washout Special Cases Corrosion Table 4-7. Most likely flooding damages. Damage Types Common Damages / Modes of Failure Structural Cracking and spalling of reinforced concrete members Hydraulic Pipes bursting Special Cases Thermal expansion Reduction of strength and material properties due to fire- induced thermal effects Table 4-8. Most likely fire damages.

Part I: Background 25 Overview of Emergency Events 4.9 Scour Flooding events can compromise the safety of bridges susceptible to scour. In the event of hydro-hazard events all scour-susceptible bridges should be monitored. The National Bridge Inventory (NBI) (FHWA 2015) denotes field 113 to identify the current status of a bridge regarding its vulnerability to scour. Table 4-9 defines the codes used in field 113. When possible, PDARs should examine the latest inspection report that details the scour rating for the bridge. These codes can help with determining if a bridge is likely to have scour related damages or impacts. Codes Description N Bridge is not over waterway. U Unknown foundation that has not been evaluated for scour. Due to risk being undetermined, flag for monitoring during flooding events. T Bridge over “tidal” waters that has not been evaluated for scour but is considered low risk. 9 Bridge foundations on dry land well above flood water elevations. 8 Bridge foundations determined to be stable for the assessed or calculated scour condition. Scour is determined to be above top of footing by assessment, calculation, or installation of properly designed countermeasures. 7 Countermeasures have been installed to mitigate an existing problem with scour and to reduce the risk of bridge failure during flood event. 6 Scour calculations/evaluation has not been made. (Use only to describe case where bridge has not yet been evaluated for scour potential.) 5 Bridge foundations determined to be stable for assessed or calculated scour condition. Scour is determined to be within the limits of footings or piles by assessment, calculations, or installation of properly designed countermeasures. 4 Bridge foundations determined to be stable for assessed or calculated scour conditions; field review indicates action is required to protect exposed foundations. 3 Bridge is scour critical; bridge foundations determined to be unstable for assessed or calculated scour conditions: scour within limits of footings or piles, or scour below spread-footing base or pile tips. 2 Bridge is scour critical; field review indicates that extensive scour has occurred at bridge foundations, which are determined to be unstable by: a comparison of calculated scour and observed scour during the bridge inspection or an engineering evaluation of the observed scour reported by the bridge inspector. 1 Bridge is scour critical; field review indicates that failure of piers/abutments is imminent. Bridge is closed to traffic. Failure is imminent based on a comparison of calculated and observed scour during the bridge inspection or an engineering evaluation of the observed scour condition reported by the bridge inspector. 0 Bridge is scour critical. Bridge has failed and is closed to traffic. Source: Modified after Richardson and Davis (2001). Table 4-9. Codes in NBI field 113.

Part I: Background 26 Overview of Emergency Events The following structures should be monitored for any of the following conditions: • Bridge – Pressure flow (bridge deck is fully or partially submerged) – Water overtopping the bridge – Misalignment, settlement, or tilt damage – Vertical or lateral displacement of the superstructure – Excessive vertical or horizontal separation at bridge deck joints – Clear sign of structural distress • Approach Roadway – Settlement damage – Water overtopping the approach roadway – Embankment erosion damage • Waterway Channel – Significant debris buildup or formation of damming – Streambed has lowered to the scour-critical elevation at pier or abutment – Water surface elevation has risen to the bridge closure water surface elevation level when such markings have been determined for a bridge. If such markings have not been deter- mined, then a judgment needs to be made on unsafe levels based on prior observation of water flow beneath the bridge. If a highway structure is experiencing any of these signs, the structure should be marked as UNSAFE and the ME informed to proceed with DDA. When grass and weeds are growing in a scoured area, it may be a long-existing issue not related to an emergency event and may not provide an immediate hazard. During periods of decreasing flow, sediments can backfill an area of scoured bed material. Scour hole sizes can also be difficult to assess due to backfill and sediment. In these instances, a risky scour situa- tion can exist but be difficult to assess. When these issues occur, specialized PDAR teams are recommended to perform PDA evaluations. These specialized PDAR teams will focus specifi- cally on scour-prone structures and can gain access to specialized equipment such as a boat, waders, or an underwater probe.