Post-Extreme Event Damage Assessment and Response for Highway Bridges (2016)

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22 ALASKA DEPARTMENT OF TRANSPORTATION & PUBLIC FACILITIES State Bridge Engineer The Alaska Department of Transportation & Public Facilities (ADOT&PF) has determined that earthquakes, scour, flood and debris flow, collision, ground acceleration, and liquefac- tion are all likely extreme events. It was also determined that there was a possibility of extreme events resulting from wind, storm surge and waves, and landslides. State Hydraulic Engineer ADOT&PF has determined that bridge damage is likely to occur from flood and debris flow, and that it is considered possible from scour and storm surge and waves. ADOT&PF’s hydraulic section’s primary form of dam- age detection is through visual inspection. ADOT&PF uses portable sonar surveys, fixed sonar surveys, and manned and unmanned sonar surveys and additional damage detection techniques to help with their assessment of bridges. A num- ber of bridges with scour sonar sensors are managed by the U.S. Geological Survey (USGS). If the scour data collected by the sensors show that there is structural concern, inspec- tion personnel are sent to verify it in the field. At times when the sonar sensors detect scour-related issues, the ADOT&PF will work with the weather service to help forecast possible weather changes that could affect the scour state. These dam- age detection techniques have proven capable of providing sufficient data for bridge damage assessment to ADOT&PF. To accommodate the high demand for the detection of dam- age in the state’s bridges, the ADOT bridge hydraulics section has agreements in place with USGS to conduct some of the inspections after major flood events. This collaborative effort provides fairly rapid response to hydrological events. Funding is in place for USGS to verify scour conditions or to conduct hydraulic discharge measurements. This is mostly useful when seeking emergency repair funds through FHWA or FEMA as characterizing the extent of storm helps put it into statistical context for communication with the decision makers. ADOT&PF has staff meetings throughout the year to dis- cuss hydraulic issues; theirs and the Inner Agency Hydrology Committee of Alaska. It is an assortment of state, federal, and some tribal personnel coming together to discuss hydrology. This chapter provides a review of the states that are using specific damage detection techniques in addition to visual inspection or have an emergency response plan in place. The emergency response plans are provided in a summary and more detailed plans can be accessed through the E-Appendix. Appendix A4 is a guide to the emergency plans included in the E-Appendix. The chapter concludes with a synthesis of emergency response planning based on information from the surveys and the agency cases in this chapter. ALABAMA DEPARTMENT OF TRANSPORTATION State Bridge Engineer Scour is considered an extreme event with high likelihood in Alabama, with the damage from wind, storm surge and waves, landslides, flood and debris flow, fire, and collision as likely causes of damage. Alabama DOT (ALDOT) does not have any established guidelines, procedures, or proto- cols for rapid damage assessment and emergency response efforts after extreme events. ALDOT uses visual inspection as the primary means of damage detection. GPR is used to search for voids in a struc- ture, as well as to occasionally determine the thickness of dif- ferent parts of a structure. ALDOT uses NDT such as ultrasonic testing and sounding with hammer. State Hydraulic Engineer ALDOT has determined that scour, storm surge and waves, and flood and debris flow are all extreme hydraulic events that are likely to occur. For structures that are susceptible to scour and flooding, a plan of action (POA) is implemented during certain rain events, in which the structures are mon- itored by inspectors and inspected immediately after the event. Streambed soundings are taken and any damage to the structure is relayed to the hydraulics section and analyzed for stability. ALDOT uses visual inspection as its primary form of dam- age detection for post-extreme event assessment. Float-outs or tethered-buried switches and portable sonar surveys to complement visual inspections are used. These have proven to be capable of providing sufficient data for bridge damage assessment for the agency. chapter four REVIEW OF AGENCY RESPONSES

23 It is through these interactions that they can maintain profes- sional connections. Through these interactions a constant pro- fessional relationship is maintained and helps with the response arrangements in the event of an extreme event. If there is a need for formalizing a joint response, that would be done by the deputy commissioner. Primarily, the maintenance branch will deal with the temporary repairs and the hydraulics branch with permanent repairs. Emergency Response Procedure Immediately after an extreme event, local maintenance and operations staff are deployed to the event location to assess the level of damage to the bridges and any threat to safety. Additional resources are mobilized as warranted by the level of complexity and the extent of damage. In the weeks follow- ing an extreme event, resources, including funding, are identi- fied and allocated based on the nature of the event (i.e., the need to protect public safety, need to restore performance, etc.). ADOT&PF has a Field Operations Guide that covers the required bridge assessments depending on the type of situation. All bridges that are damaged should be approached with caution and not be crossed if significant issues are identified (Table 5). It is important that any bridges be closed immedi- ately if any critical deficiencies are found. The Bridge Section should be notified of all findings and procedures. Category 1 Assessment Teams are in charge of initial inspections after an extreme event and will be responsible for inspecting, recording, and reporting conditions along their assigned routes or areas. The inspection checklist for Category 1 Bridge Assessment includes checking: • Bridge approach and bridge deck • Bridge rail • Wing walls • Abutments • Bearings—steel rockers, elastomeric pads, etc. • Girders • Concrete piers and columns • Steel piling • Bent caps • Utilities. Category 2 Assessment Teams are responsible for inspecting all state-maintained struc- tures and non-state structures that cross state rights-of-way within the disaster area to ensure that they are functional and do not impair traffic, to make sure any damaged structures are properly barricaded, and to report any findings to the Emer- gency Operations Center. The inspection checklist for Cat- egory 2 Bridge Assessment includes examining: • All items listed under Category 1 Bridge Assessment • Decks—alignment, deflections, large cracks • Parapets/rails—alignment, shifting • Expansion joints—unusual openings, displacements • Trusses—alignment, plumb of main members, deformed or cracked members • Bearings—overexpanded, underexpanded, shifted, top- pled, or missing steel bearings or rollers, unusual defor- mation of elastomeric bearings • Superstructures: – Steel-deformations, cracks, lack of support at abut- ments and piers, unusual deflections, buckles – Concrete-lack of support, open cracks, unusual deflections – Hinges—lack of supports, broken or misaligned link plates, unusual vertical or horizontal displacements. • Substructure—large cracks, settlement, shifting, tilting, buckled columns • Utility attachments—attachments severed, kinked, buck- led, or loose lines (phone, electricity, etc.), severed pipe- lines (natural gas, oil, water, etc.). TABLE 5 DIFFERENT ACTIONS TAKEN BY ALASKA DOT IN CASE OF EMERGENCY CONDITIONS Bridge Assessment Actions 1. CLOSE. Shoring not feasible 2. CLOSE. Shore to open 3. OPEN Bridge is collapsed or impassable. Close to all traffic. Damage is serious, but shoring would support bridge and allow re- opening. Based on inspection, the bridge should remain open.

24 During a flooding event: • Examine bridge for: – Loss of embankment material from under abutments (may form a void underneath approach pavement) – Loss of approach roadway. • Inspect for embankment toe erosion adjacent to bridge. • Inspect for scour at bridge piers: – Take soundings at piers if practical and safe. • Look for settlement of foundations resulting from scour: – May show up as a sag in the superstructure. – Look for loss of piles, etc. – Report on debris build-up at bridge, particularly if it is causing or may cause damage to the bridge. Category 3 Assessment Teams will be assembled in the event of significant bridge damage. They will assist the Emergency Operation Center in the assessment of damages, initiation of plans for emer- gency repairs, and in the collection of data for use in prepar- ing interim and long-term repairs to the damaged structures. This team will begin its assessments after the Category 1 and Category 2 results have been evaluated and prioritized. The Alaska DOT uses visual inspection as its primary approach for damage detection. Sonar surveys are another technique used to analyze parts of structures that are under- water, where visual inspection is not an option. Often, first responders will send digital photos to the Bridge Office for remote assessment of conditions. Following previous seismic events, it became apparent that ADOT&PF first respond- ers with no engineering background became uncomfort- able assessing the level of damage and the safety of leaving bridges open. The reason was that the first responders experienced a major ground shaking, yet saw almost no structural damage or ground movement that would require bridge closure. CALIFORNIA DEPARTMENT OF TRANSPORTATION State Bridge Engineer Caltrans has determined that in the state vehicle collisions are the most likely cause of damage to bridges, followed by scour and the possibility of earthquakes, landslides, flood and debris flow, fire, and ground acceleration. State Hydraulic Engineer Caltrans has determined that scour, storm surge and waves, and flood and debris flow are all extreme hydraulic events that could occur and cause damage to bridges. Caltrans monitors rainfall and forecasts and sends lists to maintenance crews of scour critical or otherwise vulnerable bridges to monitor during an event. After the event, hydraulic engineers will investigate in further detail. Hydraulics Rapid Damage Detection Techniques Caltrans uses many different types of damage detection tech- niques for rapid post-extreme event damage assessment. These methods include visual inspection, float-out or tethered-buried switches, time-domain reflectometry buried or driven rod devices, portable sonar surveys, fixed sonar surveys, manned and unmanned sonar surveys, and tiltmeters and/or velocity meters. These methods have proven to be capable of providing sufficient data for bridge damage assessment after an extreme hydraulic event. Emergency Response Procedure Caltrans’ Structure Maintenance and Investigations (SM&I) is the agency’s lead bridge inspection unit. SM&I maintains the California bridge files and is the official lead responder to all bridge-related emergencies. SM&I bridge emergency responses are in two phases: an initial first response and rapid damage assessment, followed by a detailed bridge inspection as needed. The initial rapid bridge assessment flags the safe and the damaged bridges, allowing the Caltrans Emergency Operations Center (EOC) to manage the response and decide the bridges that need to receive repair or replacement. In major events, the affected District EOC will prioritize the routes that need to be cleared. The size of the event determines the overall response. For example, the earthquake emergency response thresholds are defined as: minor earthquakes (4.0 to 5.5 magnitude), moder- ate earthquakes (5.6 to 6.1 magnitude), and major earthquakes (magnitude of 6.2 and above). Each threshold has a different emergency response protocol. After minor earthquake events local DOT maintenance crews drive along the affected routes and report on any minor bridge damage they find. An inspection team of engineers is then deployed for the official inspection and to document suggested repair. Moderate earthquake events may require several teams of SM&I inspectors to perform the initial damage assessments. Since 2000, for earthquakes of a magnitude of 6.0 or less, there has been no earthquake-related bridge damage found that affected traffic or resulted in bridge closures. Emergency responses to major earthquakes have var- ied dramatically. The 6.8 magnitude Northridge Earthquake resulted in six collapsed structures and 600 other bridges with minor to moderate damage. A 7.8 magnitude earthquake is estimated to potentially result in 60 to 80 bridges closing and 4,000 bridges requiring inspection. SM&I trains Caltrans inspectors for earthquake inspec- tions as well as for flood and over-height collision inspec- tions. All SM&I inspectors are civil engineers and National Bridge Inspection Standards team leaders, capable of analyz-

25 ing the capacity of the bridges and conducting shoring activi- ties if needed. Yearly training consists of approximately 16 to 20 hours of earthquake inspection instruction and drills. The training also includes all of the office support for the field inspectors and those who will work in the SM&I Bridge Emer- gency Response Center in Sacramento. Structure Mainte- nance Emergency Response Plan is maintained and regularly updated, and available to all employees on the SM&I website: http://smi.dot.ca.gov. COLORADO DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Colorado, the mostly likely extreme events that would result in damage to bridges are landslides, fire, and over-height vehi- cle collisions. Damage from scour, wind, and flood and debris flow is likely to happen, as well as a possibility of bridge dam- age resulting from blast. Structures Rapid Damage Detection Techniques Colorado DOT (CDOT) uses various types of damage detection techniques. The primary form of damage detec- tion is visual inspection. Additionally, different forms of NDT techniques are used to aid with the damage detec- tion process. Sounding with a hammer and GPR are meth- ods that are commonly used for damage detection. There has also been limited testing with Spectral Analysis of Surface Waves. Spectral Analysis of Surface Waves is based on measuring surface waves spreading in layered elastic media. State Hydraulic Engineer CDOT has determined that bridge damage from scour and flood and debris flow is likely to occur during the extreme flood events. Typically during a flooding or high water event at a bridge structure, the CDOT maintenance team will moni- tor the structure and follow the Bridge Scour Plan of Action. If water rises to the level of the low girder, the bridge will be closed and the roadway shut down. Hydraulics Rapid Damage Detection Techniques CDOT uses visual inspection as its primary form of rapid damage detection on bridges. Other techniques used after an extreme hydraulic event include probing rods and rope with an attached weight. The data collected from these methods can be used immediately after an extreme hydraulic event to rapidly assess the extent of the damage to a bridge. CDOT believes that these current methods are able to provide suf- ficient data for bridge damage assessment after an extreme hydraulic event, but that the use of GPR and portable sonar surveys would be able to improve on it. CONNECTICUT DEPARTMENT OF TRANSPORTATION State Hydraulic Engineer The Connecticut DOT (ConnDOT) has determined that flood and debris flow is an extreme hydraulic event that is likely to damage bridges. Scour and storm surge and waves are also considered a possible bridge damaging event. Hydraulic Rapid Damage Detection Techniques ConnDOT’s rapid damage assessment of bridges comes pri- marily from visual inspection. Other techniques such as por- table sonar surveys, fixed bridge scour monitors, and sonar transducers have also been used. These techniques have been capable of providing sufficient data for bridge damage assess- ment after an extreme hydraulic event. Emergency Response Procedure ConnDOT uses the BridgeWatch system to monitor scour crit- ical bridges, potential extreme storm events, and flooding. The automated monitoring application provides alerts of potential critical events based on a comparison of real-time weather and hydraulic data with thresholds and information previously uploaded in the application. ConnDOT reviews and responds, if necessary, to the alerts. Bridge inspection personnel respond to the bridge alert location(s) to check for flooding and any signs of damage and/or distress. The bridge may be closed if the “critical” water surface elevation is reached or determined to be unsafe. A post-flood inspection of the bridge would then be conducted as well, which may include the use of divers. ConnDOT can typically anticipate and prepare to respond to events based on forecasts from the National Weather Service (NWS) and the news media. A POA has been prepared for each scour critical bridge. An established “Emergency Decla- ration” process can be used to perform immediate repairs and timely replacements of damaged structures. DELAWARE DEPARTMENT OF TRANSPORTATION State Hydraulic Engineer Delaware DOT (DelDOT) has determined that scour, storm surge and waves, and flood and debris flow are all extreme hydraulic events that are likely to occur. After storm events, DelDOT inspects all bridges and culverts in the affected area for damage from scour, debris or any other sources. Hydraulic Rapid Damage Detection Techniques DelDOT uses visual inspection as its primary damage detection technique. Portable sonar surveys are also used to help with post-extreme event damage assessment. DelDOT believes that these damage detection techniques are capable of providing

26 sufficient data for bridge damage assessment after an extreme hydraulic event. FLORIDA DEPARTMENT OF TRANSPORTATION State Bridge Management Inspection Engineer In Florida, the most likely extreme events to cause bridge damage are over-height vehicle collisions and barge colli- sions in navigable waters. There is also a possibility of dam- age from wind, storm surge and waves, flood and debris flow, fire, ground acceleration, and liquefaction. Structures Damage Detection Techniques The most common form of damage detection used by the Florida DOT (FDOT) is visual inspection. The agency also uses limited sonar surveys for assessing parts of structures that are underwater. They have scour monitoring systems on a few selected bridges. One FDOT district developed a method where (during a storm) a scour sonar monitor is attached to a pole, which is then lowered into the water and used to measure scour depth. FDOT uses several types of NDT techniques such as dye-penetrant testing, which is used to locate cracks, porosity, and other defects that break the sur- face of a material. Magnetic particle testing is used to inspect large areas for surface and subsurface flaws. Ultrasonic testing is used to detect surface and subsurface flaws at a greater depth than other techniques, as well as being able to detect the thickness of materials. Emergency Response Procedure To minimize the disruptions to transportation service from damaged to bridges, FDOT uses a prioritizing scheme to identify the most critical bridges following the report for operations management. FDOT uses PONTIS, which is a comprehensive bridge management system developed as a tool to assist with bridge management. PONTIS stores bridge inventory and inspection data, formulates network- wide preservation and improvement policies to evaluate the needs of each bridge in a network, and makes recommen- dations for what projects to include in an agency’s capital plan for deriving the maximum benefit from limited funds. Bridges identified by this program will be provided to the Domestic Security Manager at the beginning of June on annual basis by the state maintenance office. In addition, in 2011, FDOT established an emergency management program that defines the roles and responsibilities of the emergency response operations centers within the agency. ILLINOIS DEPARTMENT OF TRANSPORTATION State Bridge Engineer Illinois DOT (IDOT) has determined that over-height vehicle collisions is the extreme event with the greatest likelihood of causing damage to bridges, followed by scour damage. Dam- ages from earthquakes, flood and debris flow, fire, ground acceleration, and liquefaction are also possible. Structures Damage Detection Techniques IDOT’s primary form of damage assessment is visual inspec- tion, which according to agency engineers is not believed to always be capable of providing sufficient data for bridge assessment after an extreme event. Sounding techniques are used on occasion to assist with damage assessment. NDT tech- niques are used minimally to assess bridge damages after an extreme event. With flooding and scour being an annual issue in Illinois, more implemented uses of depth finding equipment and sonar surveying is believed to be something that would improve the currently used bridge damage assessment pro- cess. During nonemergency events, the increased use of infra- red testing, impact-echo testing, and GPR could improve the assessment of bridges as well. IDOT currently uses a BridgeWatch System that collects data from weather and stream gages. This system is used to predict where flooding could occur. IDOT can then use that information to monitor any bridges that are at risk to scour damage and be able to alert the public about problems with those bridges if necessary. Bridge Management Engineer IDOT has determined that scour and flood and debris flow are both extreme hydraulic events that are highly likely to occur. The agency uses the BridgeWatch hydraulic monitoring sys- tem to identify events that could cause scour. Inspection per- sonnel are alerted to these events and dispatched to the bridge site to inspect for scour hole and debris build up. Inspection personnel may monitor or close the bridge depending on water flow. IDOT has a Structural Services Manual that it uses as a guideline for repairs, inspections, ratings, and permits. Hydraulic Rapid Damage Detection Techniques The primary form of damage detection used by IDOT is visual inspection. It also uses float-outs or tethered switches as well as portable sonar surveys to assist in its rapid post-extreme event damage assessment. These methods have proven to be capable of providing sufficient data for bridge damage assess- ment. IDOT is not aware of more robust damage detection systems, but is looking for alternative techniques, because identifying scour during a flooding event is currently challeng- ing; often the flood must subside before the true scope of dam- age can be determined. Illinois has a policy to close structures when they undergo pressure flow because of the difficulty in detecting scour. Emergency Response Procedure In the case of an extreme event, an EOC is in charge of coor- dination between different agencies (law enforcement, con-

27 tractors, etc.). IDOT has a plan for Earthquake Response Assessment of Highways and Bridges. This plan is primarily for the southern part of the state because it is at a higher risk of seismic activities due to proximity to New Madrid Fault region. It includes First Level Assessment and Second Level Assess- ment teams that proceed in the same way that IDOT’s Level 1 and Level 2 assessments are done. IDOT has a Third Level Assessment team, which is comprised of highly specialized engineers and technicians with expertise in inspection, field assessment, planning, design, and bridge repair. In the event of a significant earthquake, the Bureau of Bridges and Structures will assemble qualified inspection teams that will assist the dis- tricts in the assessment of damages, initiate plans for emergency repairs, and collect data to forward to the central office design staff for use in preparing interim and long-term repairs to damaged structures. IDOT is currently developing guidelines for evaluating bridge damage during extreme events other than earth- quakes, such as man-made extreme events. However, for security purposes, these guidelines will not be accessible to the public. INDIANA DEPARTMENT OF TRANSPORTATION State Bridge Engineer Indiana DOT (INDOT) considers vehicle–bridge collisions as the hazard with the highest likelihood of damage to bridges, followed by scour and a possibility of earthquakes, landslides, flood and debris flow, and fire. Structures Rapid Damage Detection Techniques INDOT uses multiple types of damage detection techniques with Visual inspection as the primary method of damage detection. Because many roads are typically inaccessible to vehicles during flood events, photogrammetry is used by hav- ing an airplane take pictures of the affected region, which assists INDOT in identifying the bridges in need of repair. NDT techniques are occasionally used to assess bridge damage. These techniques include magnetic particle testing, ultrasonic testing, infrared testing, and GPR. State Hydraulic Engineer INDOT has determined that both scour and flood and debris flow are extreme hydraulic events that are likely to occur and cause damage to bridges. For scour, INDOT’s bridge inspectors will inspect the bridges in accordance with the scour plans of action. With floods and debris, the INDOT’s maintenance staff is generally on site. They will close the road if warranted and will make plans to remove any debris. If a structure is endan- gered, bridge inspection is called out for structural assessment and, if needed, hydraulics and bridge design groups are brought in for scour countermeasure designs and bridge rehabilitation or replacement. Hydraulic Rapid Damage Detection Techniques INDOT uses visual inspection as its primary method of dam- age detection. Buried or driven rod devices are also used to help with rapid post-extreme event damage assessment. These methods have proven to be capable of providing sufficient data for bridge damage assessment. INDOT also has an emergency on-call contract with a consulting firm that has access to any other devices required to properly assess the extent of damage to a bridge. Emergency Response Procedure INDOT has prepared a Field Guide for the Post-Earthquake Safety Evaluation of Bridges and Roads to provide agency personnel of various backgrounds with a rapid and effective methodology for the post-earthquake safety inspection of bridges and roads in Indiana (Figure 13). In the field guide, there is the necessary material for a systematic safety evalua- tion of bridge structures and roads for a wide range of INDOT personnel. The necessary material is arranged according to two inspection levels: Level 1 inspection consists of the rapid visual evaluation of bridges and roads in the affected area in order to flag obviously unsafe structures and roads. Level 2 inspections is a more in-depth safety evaluation of bridges and roads, as well as temporary repair and long-term monitor- ing techniques (Figure 14). Indiana does not experience a large number of earthquakes; however, it has collected data from several earthquakes around the world, such as the 1994 Northridge Earthquake, 1999 Taiwan Earthquake, and 1995 Kobe Earthquake. Using these examples, it has created a POA for responding to an earth- quake event that consists of plans for a Level 1 and Level 2 inspection. Level 1 Inspection General Procedure 1. Begin the inspection of the assigned bridges on the pre- viously determined route after collecting the necessary tools for the inspection. 2. Minor roadway deficiencies are to be recorded on the form including pavement damage, earth embankment failure, road obstructions, and failure of the traffic con- trol devices. The unit, subdistrict, and district should be informed immediately of any road or bridge damage that requires the closing of the roadway to traffic. 3. Complete Level 1 inspection form. Complete one row per bridge inspected. The suggested step-by-step pro- cedure is listed here. 3.1. Upon arrival to the bridge site, review and verify the bridge number. 3.2. Record the arrival time. 3.3. Check the traffic flow on the bridge. Presence of traffic on the bridge that does not indicate that the bridge is safe. Inspect all bridges assuming they may be damaged.

28 3.4. Upon arrival, approach the bridge with caution and never walk immediately directly under or over the bridge. Do not cross the bridge without first sighting down the curb or rail line and checking the underside for structural damage. 3.5. Prepare an inspection routine of the different com- ponents. Assign inspection tasks. Begin by inspect- ing approaches and continue in the order listed in the inspection form. Upon starting substructure inspection, each inspector should go down a differ- ent side of the bridge to provide safety by separa- tion and to speed the inspection. 3.6. Discuss observations with the other members of the team and evaluate the condition. 4. After completing Items 3.1 through 3.6 in the form with the comments YES, NO, or DRN (Detailed Review Needed), the team should come to an agreement regard- ing the condition of the bridge and enter this in one of the last three columns of the form, as appropriate. If a bridge received at least one YES for the dam- age types 1 through 5, either a RED tag for closure, or if a more detailed inspection is needed (Level 2) a YELLOW tag is entered. In case of no damage, a GREEN tag is entered. 5. Additional recommendations and observations about the bridge and roadway can be written in the box pro- vided at the bottom of the form. 6. If the bridge is given a RED tag requiring barricades, the unit, subdistrict, and district should be informed imme- diately and the disaster closure procedure outlined in Section 6.4 of the field guide followed. If the bridge can be traversed, but repairs are needed, place a YELLOW ribbon; if it is undamaged use a GREEN ribbon. Attach ribbons to the bridge signpost and note time, date, and inspector initials. 7. Record the time indicating the end of the inspection of the assigned bridges in the space provided at the top of the form. FIGURE 13 Flowchart of post-earthquake response assessment.

29 Level 2 Inspection General Procedure 1. Start the inspection of the assigned bridge after col- lecting the necessary tools for the inspection. 2. Record the arrival and departure times. Complete the necessary information about the bridge, route, and date and time. Note the difference between inspection day and time and the day and time of the main shock. 3. Examine the data from Level 1 inspection report for the bridge. 4. Check the traffic flow through the bridge. This may help to reach a conclusion about the condition of the bridge. 5. Prepare an inspection plan for the different bridge com- ponents and prepare assignments for the inspection. 6. Inspect the superstructure and substructure following the sequence given in the Level 2 form. 7. Note the observed damage by checking the necessary boxes. Fill out the form shown in Figure 15 of the field guide. It contains six main damage type definitions for the different elements of the bridge structures, and comments and a section to make specific recommenda- tions. One form must be used for each bridge inspected. 8. Discuss the observations with the members of the team and come to an agreement on the condition. 9. The final rating should be written on the bottom of the form. 10. If the conclusion is that the bridge/road must be closed, or barricades are required, contact the unit, subdistrict, and district immediately. 11. Note any additional recommendations and conclusions in the box. The back of the form can be used for addi- tional explanations or sketches. 12. Place appropriate marked ribbon on the bridge sign to inform later inspectors about its condition. INDOT has a formal procedure for the planned closing of a road or bridge that includes pre-closure notification to FIGURE 14 Damage classification tables for bridges.

30 FIGURE 15 Initial emergency response flowchart.

31 the public (through the media and signs), marking a detour or approach, and signing the actual barricade closure. In a major disaster, this procedure will be impossible to follow; however, INDOT has a responsibility to take all reasonable actions to notify and protect the public as soon as the need for a road closure is known. To that end, each unit shall maintain a minimum of one set of “Road Closure” signs with type B flashers and sign supports for each primary disaster route in their unit. The Level 1 inspectors shall load one Road Clo- sure setup (two signs) onto their truck before starting their inspection. If the need for a closure is encountered during the inspection, the signs will be put on each approach and the unit and subdistrict be immediately notified by radio so that the approach signing and barricading is done and a detour can be placed in a timely manner by the follow-up person- nel. Once the sign is in place, the Level 1 inspectors shall continue the inspection on their primary route using state and county maps to find a way around the closure. If additional closures are encountered, that information is to be relayed back to the unit and subdistrict for assistance. One inspector may have to remain at the closure until relieved if no sign- ing or other traffic control is available (local law enforce- ment will assist in this case, if available). The subdistrict is to complete State Form 1866 to notify other agencies of the emergency closure. The Level 1 inspection must be done as quickly and accurately as possible so that a determination of the extent of the damage can be made and repairs started. IOWA DEPARTMENT OF TRANSPORTATION State Bridge Engineer Iowa DOT has determined that scour is considered an extreme event highly likely to cause damage to bridges, followed by flood and debris flow and collisions. Bridge damages occur- ring from wind, landslides, and fire are also considered a possibility. Structures Rapid Damage Detection Techniques Iowa DOT uses several different types of rapid damage detec- tion techniques. Visual inspection is the primary form of dam- age detection for Iowa DOT. Infrared radar, sonar surveys, and hand-held NDT are all different types of rapid damage detection techniques used by the agency to help provide more in-depth inspection when there is believed to be more damage than what is visible. When trying to access data from other agencies, the greatest challenge is finding the correct parties with the proper data. Iowa DOT believes that its current damage detection tech- niques are capable of providing sufficient data for bridge damage assessment. The primary bridge damage that Iowa DOT experiences is a result of collisions from over-height vehicles. The detection of damage to girders is normally ade- quately assessed through simple hand-held NDT techniques. State Hydraulic Engineer Iowa DOT has determined that scour is a likely extreme hydraulic event. Flood and debris flow is considered to be a possible extreme hydraulic event. Iowa DOT performs bridge scour inspections after significant flooding for impacts to foundation or bridge beams. Bridges that are scour critical are closed until an inspection can be performed. Hydraulic Rapid Damage Detection Techniques Iowa DOT uses visual inspection as its primary damage detec- tion technique. It also uses portable sonar surveys and 3D laser scanning to assist with its rapid post-extreme event damage assessment. These methods have proven to be capable of pro- viding sufficient data for bridge damage assessment for the agency. Emergency Response Procedure Iowa DOT has created an Emergency Response Manual to cover over-height collisions to bridges. The purpose of this manual is to define and document the desired procedures fol- lowing an over-height collision that are to be followed by emergency and Iowa DOT personnel to ensure public safety, coordinate repairs, and maintain or restore traffic as quickly as possible. The manual is intended to ensure consistency in the response, keeping in mind the following priorities: (1) pre- serving life, minimizing injury, and preserving public safety; (2) restoring essential services; (3) protecting property and the environment; and (4) providing timely and accurate emer- gency communication to the public through media. Iowa DOT has created a general flow chart for the initial emergency response (Figure 15), bridge assessment (Fig- ure 16), and repair, design, and contracting procedure after an over-height vehicle collision causing bridge damage. The Iowa Homeland Security and Emergency Management Division has developed an overall Iowa Emergency Response Plan to provide instructions, policies, and explanatory informa- tion related to many or all of the agencies and entities involved in emergency and disaster response. This plan is based on the premise that the preservation of life, health, safety, and prop- erty, and the minimization of human suffering are the top pri- orities during an emergency or disaster response. The Traffic Operations Center of the Iowa DOT Systems Operation Bureau provides the primary coordination of response and recovery efforts for the majority of over-height vehicle impacts. Assessment of a damaged bridge typically would be a two- phase process. At the time of the initial emergency response, an assessment must be made as to whether traffic can be allowed on the damaged bridge and whether traffic can pass below the damaged bridge without the potential for debris falling. Once the initial decision is made and traffic operations are either detoured, resumed, or resumed with restrictions,

32 FIGURE 16 Detailed bridge assessment flowchart.

33 a detailed inspection and assessment of the damage can be made and a load rating performed. This detailed assessment would be used to confirm the initial disposition of the bridge and then to initiate repair design and a contract for repairs. A three-level guideline system (based on varying severities) is used to identify emergency incidents (Figure 17). A Priority Level 1 emergency incident is the highest level incident and requires the greatest level of notifications. A Level 1 incident also requires a call to the Iowa DOT’s Direc- tor of Statewide Emergency Operations. Level 1 notifications are triggered by one of the following events: • Closure of all lanes in either direction of an interstate route or a four-lane primary road with an expected dura- tion of longer than 4 hours. • Full closure of both lanes for a two-lane primary road with an expected duration of longer than 8 hours. • A hazardous materials (HazMat) incident that is a risk to public safety (evacuation). • Damage to system infrastructure causing a disruption of service. • An incident requiring activation of the state EOC. A Priority Level 2 incident has a lower level of required notifications. Level 2 notifications are triggered by one of the following events: • Closure of all lanes in either direction of an interstate route or a four-lane primary road with an expected dura- tion of less than or equal to 4 hours. • Full closure of both lanes for a two-lane primary road with an expected duration of less than or equal to 8 hours. • A HazMat cargo shipping release. • A multi-casualty crash. • Fatalities. • Incidents crossing district jurisdictional lines. Priority Level 3 incidents have the lowest level of required notifications. If a Level 3 incident occurs in a metropolitan FIGURE 17 Repair design and contract letting flowchart.

34 area during rush hour, lasts less than 30 minutes, and does not have a significant impact on traffic, then no Emergency Inci- dent Notification is required. Otherwise, Level 3 notifications would be triggered by: • Any road or lane closure reported in a district with either short-term or local impacts. • Any HazMat release reported in a district. • Any accident on the primary highway system that is reported in a district. Critical structural and safety-related deficiencies found during the field inspection or as a result of a structural analysis of the bridge should be immediately brought to the attention of the bridge owner or responsible agency by the program manager or team leader. This process alerts the bridge owner so that: 1. Timely action is taken to ensure the safety of the trav- eling public, 2. Damage or deterioration can be repaired in a proper and timely manner, and 3. The damage and repairs are documented in the bridge file. There are several factors that determine whether to repair or replace a damaged bridge. The primary factor is the sever- ity of the damage. Other factors that would contribute to the decision include age of the structure, bridge repair history, an evaluation of the available clearance envelope, past inspection issues, and whether the bridge has already been scheduled for replacement. KENTUCKY TRANSPORTATION CABINET State Bridge Engineer The Kentucky Transportation Cabinet (KYTC) has deter- mined that vehicle and vessel collision extreme events had the highest likelihood of causing damage to bridges followed by scour, wind, flood and debris flow, and fire. Earthquakes, landslides, blast, and ground acceleration are also consid- ered possible extreme events for causing bridge damage. Structures Rapid Damage Detection Techniques KYTC uses visual inspection as its primary form of rapid damage detection. The agency has access to other techniques such as GPR or infrared when needed. KYTC works with the University of Kentucky when they require different forensic tests on certain materials. Emergency Response Procedure KYTC does not have a specific set of guidelines or emer- gency action plans in the case of an extreme event damaging a bridge. The response plans vary from district to district and typically change as personnel within the districts change. After an extreme event, the District Bridge Inspector will go to the affected site to evaluate damages and, if necessary, will request that the chief bridge inspector and/or the chief bridge inspection engineer to immediately visit the site. KYTC gives priority to bridges for repairs or replacement based on need of repair, frequency of the use of bridges that need repair, and how an improvement would help the surrounding regions. These factors are considered by the district offices, which then notify the central bridge office of the next required steps. On occasion the agency has encountered coordination prob- lems with law enforcement. Reports for over-height vehicle collisions are not always completed by the police after they occur, which makes it difficult for KYTC to know if a report has been completed or not when they find a damaged bridge with debris still in the area. LOUISIANA DEPARTMENT OF TRANSPORTATION & DEVELOPMENT State Bridge Design Engineer In Louisiana, the most likely extreme events that would dam- age bridges are over-height vehicles and marine vessel colli- sions. Scour, wind, storm surge and waves, flood and debris flow, and fire are also likely events. Blast damage is consid- ered a possible cause of bridge damage. Storm surge becomes a problem to bridges, particularly after hurricanes. The storm surge may cause buoyancy on low level bridge spans, which causes the spans to lift off the substructure and fall in the water. A high number of movable bridges have been damaged as a result of storm surge. According to Louisiana Department of Transportation & Development (LaDOTD), cold weather events are also a cause for concern for bridge operations. Because cold weather events are not common in Louisiana, the necessary roadway equipment and de-icing materials must be carefully planned for before an event occurs. LaDOTD has an emergency operations group that initiates before, during, and after all extreme events. The operations group also has yearly training exercises to plan for possible events. Structures Rapid Damage Detection Techniques Visual inspection is the primary form of damage detection used by LaDOTD. MICHIGAN DEPARTMENT OF TRANSPORTATION State Hydraulic Engineer Michigan DOT (MDOT) has determined that scour and flood and debris flow are the most likely extreme events that could occur and cause damage to bridges. Storm surge and waves are also considered to be possible causes resulting in damage

35 to bridges. During flood events, bridges and culverts are monitored. A bridge may be closed owing to pressure flow or if settling has occurred. After the event, the structure is inspected, stream cross sections are taken, debris is removed, and the structure is inspected before being reopened to traffic. Hydraulics Rapid Damage Detection Techniques MDOT primarily uses visual inspection for rapid damage detection. This however cannot always be used immediately after a flood event. Often times MDOT must wait for the water levels to subside so that it is safe to assign their inspec- tion personnel. MINNESOTA DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Minnesota, the most likely extreme events that would dam- age bridges are over-height vehicle collisions followed by scour. Landslides and flood and debris flow are also a possible cause of damage to bridges. Structures Rapid Damage Detection Techniques The emergency responder contacts the Minnesota DOT (MnDOT) district office. The district bridge engineer then assesses the damage. Depending on the extent of the damage, the district will contact the central bridge office for support in safety inspection, analyzing, and determining next steps. MnDOT has established an emergency contact list to help with communications at any time. MnDOT’s rapid damage detec- tion techniques include visual inspection, electro-optical imag- ery, photogrammetry, accelerometers, inclinometers, NDT, and 3D laser scanning. Photogrammetry is used in the form of flight surveys for assessment of large flooded areas. When the I-35W Bridge collapsed, daily flights were undertaken to assess the dam- ages. Accelerometers and inclinometers are used for bridges to monitor movements and deformations. Some bridges with the spread-footing are scour susceptible and as such are monitored frequently to ensure that the scour depth doesn’t exceed the critical thresholds. The different types of NDT techniques used by MnDOT include rebar scanners, chain drag, the Schmidt hammer, infrared cameras, GPR, magnetic particle testing, and ultrasonic testing. Rebar scanners are used for deter- mining the depth of a concrete cover and they can also help to estimate the amount of reinforcement in a section. A chain drag is used to check for delaminated areas. The Schmidt hammer helps to determine an approximation of a concrete’s strength. Infrared cameras are used for viewing the under- side concrete of bridges to show areas with possible damage. Laser scanning is used in the form of LiDAR in most cases. LiDAR is used in locations that have a high frequency of rock falls. Many times there are seams in the rock where water constantly drips through the seams, which cause the seams to crack and grow, leading to falling rocks. LiDAR is used to compare changes in the rock from the previous survey of the area and to find sections that may have become unstable. For the I-35 bridge collapse, the entire bridge was laser scanned before it was removed (for legal purposes, not typically used on bridge hits). The state bridge engineers at MnDOT believe that hav- ing technologies such as bridge health monitoring provide a faster but not necessarily reliable approach for the detection of damage in bridges. These systems primarily have helped with the confirmation of the design criteria such as creep, shrinkage, and other stressors; however, most of the systems in place stopped working in less than 10 years. Over-height vehicle detection warning systems (although not a damage detection system) is another technology that could reduce the likelihood of over-height vehicle colli- sions. This technique has been implemented in two Minne- sota bridges. A laser scans the traffic and detects if any traffic is above a certain height. Based on that, a warning sign or flashing lights will appear and will alert truckers that they most exit the highway at the next exit before goings underneath the bridge. This was initially used because a bridge was hit multiple times and instead of replacement it was determined to be cheaper to install the over-height detection system. State Hydraulic Engineer MnDOT has determined that scour and flood and debris flow are the most likely extreme hydraulic events that could dam- age bridges. MnDOT has developed a bridge scour POA for scour critical bridges that require monitoring during flood events. Bridge scour is included every other year in the annual bridge inspector training. A Bridge Office Flood Response Plan was also developed to help prioritize bridge and flood monitoring efforts. Hydraulic Rapid Damage Detection Techniques MnDOT uses several different types of techniques for rapid post-extreme event damage assessment of bridges. Visual inspection is the primary detection method. Other tech- niques such as float-outs, portable sonar surveys, manned and unmanned sonar surveys, and 3D laser scanning are all used to compliment visual inspection in bridge damage assess- ment and can all be used immediately after an extreme event to assess the extent of bridge damage. These techniques have proven to be capable of providing sufficient data for bridge assessment after extreme hydraulic events. A few other tech- niques, such as tethered-buried switches, fixed sonar sur- veys, tiltmeters, and velocity meters, have been tested but are not regularly used.

36 MnDOT has two bridges that have used fixed sonar as a part of a scour monitoring technology implementation research project. Prior to this project, MnDOT only used portable monitoring devices. The fixed sonar devices are capable of continuous scour monitoring, which is preferred, especially during high-water events. The scour monitoring systems installed on both bridges operated for 3 years with some outages from various causes (most likely power and com- munication issues); however, the overall performance was considered to be acceptable. The agency uses float-outs and tethered-buried switches in multiple locations. The test runs on some of the float-outs showed that not only the hardware needs to be maintained but also the programming and data logging needs to be checked. MnDOT also has an inter-agency agreement with the USGS. This agreement includes a section where money is allocated to involve USGS in scour monitoring in addition to the MnDOT in-house capabilities. On occasion, in the event of a flood, especially if the USGS is already mobilized to the area, they help MnDOT with monitoring of scour at bridge locations. Emergency Response Procedure MnDOT is one of the states that has a prepared emergency relief (ER) procedure that is developed with the goal of provid- ing MnDOT staff with guidance to effectively and efficiently administer the ER program. According to these guidelines, the FHWA ER manual is to be used for additional guidance and clarification. The applicability of the ER program to a natural disaster is based on the extent and intensity of the disaster. Damage to highways must be severe, occur over a wide area, and result in unusually high expenses. In the ER manual, the emergency repairs are distin- guished from the permanent repairs. Emergency repairs are made during and immediately following a disaster to restore essential traffic to minimize the extent of damage or to pro- tect the remaining facilities, whereas permanent repairs are undertaken, normally after emergency repairs have been completed, to restore the highway to its pre-disaster condition. Emergency Repairs Emergency repairs are repairs made during and immediately following a disaster to restore essential traffic in order to minimize the extent of damage or to protect the remaining facilities. Typical examples of emergency repairs are: • Regrading of roadway surfaces, roadway fills, and embankments • Debris removal • Erection and removal of barricades and detour signs, flagging and pilot cars during the emergency period, and placement of riprap around piers and bridge abutments to relieve severe on-going scour action • Dynamiting and other removal of drift piling up on bridges, including the rental of boats • Placement of riprap on the downstream slopes of approach fills to prevent scour during overtopping of the fill • Removal of slides • Construction of temporary roadway connections (detours) • Erection of temporary detour bridges • Replacement of approach fills • Use of ferry boats to provide temporary substitute high- way traffic service. Permanent Repairs Permanent repairs are administered using normal federal-aid contracting procedures, although use of streamlined proce- dures is encouraged (e.g., A + B bidding and reduced advertis- ing period). The selection of the contracting method follows 23 CFR 635.204. Determination of More Cost Effective Method or an Emergency. The intent of the federal-aid program is to ensure an opportunity for free, open, and competitive bidding whenever possible. Figure 18 is a diagram that describes the most desirable contracting methods according to FHWA. MISSISSIPPI DEPARTMENT OF TRANSPORTATION State Bridge Engineer Mississippi DOT had identified landslides and over-height vehicle collision as extreme events with the highest like- lihood of occurrence, followed by scour, storm surge and waves, and flood and debris flow. Damage from earthquakes, wind, ground acceleration, and liquefaction are considered a possibility. Structures Rapid Damage Detection Techniques Mississippi DOT uses visual inspection, satellite remote sens- ing (SRS), photogrammetry, LiDAR, and hand-held NDT. Use only when necessary Use whenever possible -------------------------------------------------------------------------------------------------------------------------------------- Force Account Emergency Contract Negotiated Contract Standard Competitively Bid Contract FIGURE 18 Most desirable contracting methods according to FHWA.

37 These techniques were all used often after Hurricane Katrina. Of these, visual inspection is the most commonly used. SRS and photogrammetry were used (after Hurricane Katrina) to determine the damage in the assets that the agency was not able to physically reach (satellite use was supplied by the fed- eral government: military and NASA). LiDAR was used to survey damaged areas to determine the extent of the repairs needed. NDT techniques were implemented to test smaller structures that did not have significant damages. The types of NDT used included ultrasonic testing, di-penetrant test- ing, and sounding (with a hammer). Smart Bridge technologies and electronic monitoring is believed to be capable of identifying damage more reliably and faster. However, it is not used often owing to high instal- lation and maintenance costs. Mississippi DOT has noted a significant increase in the number of companies wanting to provide Smart Bridge technologies; however, they have not been used thus far. Emergency Response Procedure Mississippi DOT has a “Bridge Structural Damage Response Plan” that is followed when the agency is notified of pos- sible structural damage to a bridge. The guidelines consist of two appendices that address the “bridge emergency notifica- tion guidelines” and “bridge structural damage emergency response guidelines.” According to the emergency notification guidelines bridge structural damage must be handled immediately in order to shut down the bridge to traffic for the safety of the public and to protect the structure from further damage. The Mis- sissippi Emergency Management Agency (MEMA) com- munications/duty officer receives an initial call regarding a bridge incident involving a state maintained roadway. MEMA provides 24-hour emergency notification to the Mississippi DOT Emergency Services Director (ESD) only for damage to a state maintained roadway. ESD is then to notify the Emer- gency Leadership Team, district contact, Bridge Division, and Public Affairs Division immediately if there is a catastrophic event resulting in a bridge failure. For any other bridge emergency incident, Mississippi DOT bridge personnel are notified the following working day (i.e., for Friday evening, contact Monday morning). For bridge emergencies involving a border state, the border state responsible for that bridge is contacted. MDOT district personnel are dispatched to inspect the damage first, before involving Bridge Division staff. U.S. Coast Guard will notify MDOT directly of coastal and major waterway bridge emergencies. Following the bridge structural damage emergency response guidelines, when structural damage to a bridge is first noticed, the District Contact Person will instruct the District Bridge Inspection Engineer to immediately inspect the bridge main- tained by Mississippi DOT to determine the extent of damage, in particular damage to piers, girders, and truss members. Upon receipt of damage assessment from the District Bridge Inspec- tion Engineer, the District Contact Person will make one of the following determinations: (1) Should the structure be closed to traffic, if not already closed, because of the extent of the damage; (2) as a result of the extent of structural damage, the District Contact Person will determine if the situation warrants an immediate or delayed response. If an immedi- ate response is warranted, the District Contact Person shall contact the Bridge Engineer and State Maintenance Engineer or their designee at the earliest hour possible. If a delayed response is warranted, the District Contact Person shall contact the Bridge Engineer and State Maintenance Engineer or their designee during the next normal working day. MISSOURI DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Missouri, scour, wind, flood and debris flow, and over- height collisions have a high likelihood of causing damage to bridges. Other possible extreme events that could cause bridge damage are earthquakes, landslides, fire, ground acceleration, and liquefaction. Structures Rapid Damage Detection Techniques Visual inspection is the main damage detection technique used by Missouri DOT (MoDOT). In case of earthquake events that would result in regional damage to bridges, immediate aerial surveillance will be flown into the affected area using MoDOT and/or other available aircraft. Aerial photographs of pertinent areas will be taken if resources are available. MoDOT engineers believe that the damage detection tech- niques currently used by the agency are capable of providing sufficient data for bridge damage assessment after extreme events, as long as the event does not cover a large area. On the occasion of a widespread event such as an earthquake it would be very difficult to be able to assess all 10,400 bridges in the state quickly. State Hydraulic Engineer MoDOT has determined that scour and flood and debris flow are extreme hydraulic events that are likely to cause damage to bridges. Hydraulics Rapid Damage Detection Techniques Visual inspection is the primary technique used by MoDOT for rapid damage detection after an extreme hydraulic event. Other techniques used include portable sonar surveys, fixed sonar surveys, and manned and unmanned sonar surveys. These techniques have proven to provide sufficient data for bridge damage assessment after an extreme hydraulic event.

38 Emergency Response Procedure MoDOT has an Incident Response Plan that is used to provide agency staff with a structured approach for responding to an emergency efficiently and effectively. The Incident Response Plan consists of topics such as continuity of operations plan, severe weather response plan, earthquake response plan, haz- ardous materials response plan, and terrorism response plan. After an incident, MoDOT’s primary responsibility is getting the road open and traffic flowing again as soon as possible. Objectives are communicated throughout the entire organi- zation by means of the incident planning process. Severe Weather The severe weather emergency response plan covers winter events, major thunderstorms, high winds, and major floods. For winter events, the central maintenance division will work with meteorological services to provide winter forecasts for each district. It will then follow the Engineering Policy Guide for snow and ice control in response to these events. For storm events, the level of response is dictated by the level of damage. For floods, the MoDOT Maintenance Division maintains a Scour Action Plan to guide the actions required for each scour critical bridge, which guides the actions required for scour critical bridges during major floods. In addition, MoDOT has a set of training protocols that are used to keep the response crews trained. Earthquakes In the event of an earthquake, immediate MoDOT staff assess- ment is used to report any obvious and confirmed bridge or road damage, debris issues, flooding, or any other conditions that would impede traffic flow. Immediate aerial surveillance is flown in the affected areas as well. Damage assessment starts with Priority 1 routes using the “Earthquake Bridge Inspection Process,” which begins immediately after an earth- quake, including any aftershocks, where available district per- sonnel pair up to form bridge inspection teams. These teams then begin inspecting the bridges as quickly as possible, by visually determining the structures that have been damaged and the extent to which continued service would create a dangerous situation to the traveling public. The bridges are then red flagged if they have been inspected and are to be closed for repair and green flagged if they have been inspected and appear to be safe for travel. A flight assess- ment of the Missouri River and Mississippi River corridors in the affected areas will also be requested. Depending on the progress of the ground inspections, other assessment flights may be implemented. MoDOT has prepared a map of earthquake emergency highway routes that shows roads with different priority levels (Figure 19). This map is used in case of emergencies to priori- tize the emergency response actions and serves as the starting point for route inspection, clearance, and repair. MoDOT has assessed its state’s stream crossings for sus- ceptibility to scour and developed Scour Action Plans for scour critical structures. These plans have been dissemi- nated to the MoDOT field staff who monitor stream levels during flood events and enact appropriate precautions (e.g., monitor, inspect, close the bridge) prescribed at these loca- tions. If a bridge is closed as a result of a Scour Action Plan or flooding, field staff notify the district EOC who share the information with the state EOC and the public. Before opening the structure, field staff performs an inspection to ensure the structural integrity of the bridge. If any damage is observed, they inform their district bridge engineer, who in turn communicates any information and concerns to the bridge division. MoDOT has broken up its Scour Action Plans into four categories: • Category A: Structures severely at risk during major flooding events. This category includes bridges with piles or footings undermined primarily because of local scour and bridges with timber pile foundations that are substantially exposed. – General Action Plan: Close structure during major flood events. Provide specific closure instructions to local maintenance personnel (emergency, communi- cations, etc.). Visually inspect the structure follow- ing all major flood events, with detailed investigation before re-opening of the bridge, if closed. – In addition to locations where field observations indicate it is needed, scour countermeasures may be warranted at locations where serious economic con- sequences would result from a failure or where it is impractical to close a structure during a major flood event. Examples of locations are large structures where considerable investment exists such as a major bridge, vital transportation links, and high average daily traffic (ADT) routes. • Category B: Structures substantially at risk during major flooding events. This category includes bridges with substantial pile or footing exposure, on high ADT road- ways, and/or with large drainage areas. – General Action Plan: Monitor scour depths during major flood events. Close to traffic if measured scour deemed to threaten the structure. Provide specific closure instructions to local maintenance personnel (emergency communications, etc.). Visually inspect the structure following all major flood events, with detailed investigation before re-opening if the bridge was closed. • Category C: Structure moderately at risk during major flood events. This category includes bridges with mod- erate to substantial pile or footing exposure mainly the result of calculated contraction scour and bridges with low approach roadways. – General Action Plan: Monitor for evidence of scour during routine inspections with additional visual inspection following major flood events.

39 FIGURE 19 Earthquake emergency highway routes.

40 • Category D: Structures minimally at risk during major flood events. This category includes bridges on small drainage areas, low ADT roadways, and/or with mini- mal pile or footing exposure. – General Action Plan: Monitor for evidence of scour during routine inspections. The timeframe for inspections depends on the level of the Scour Action Plan that is put into place. As the water rises, MoDOT engineers determine if the bridge is at risk and whether or not a closure is necessary. Based on the location of the bridge, it can sometimes be easily inspected during the flooding event. Other times it is not accessible to inspect until after the water level subsides. For bridges that are not considered to be at high risk to scour damage, they may not be inspected until the time of their routine inspection. The timeframe for repairs depends on the importance of the bridge to the transportation network and the level of effort it will take to repair and restore the bridge to normal conditions. Other factors include the availability of funds, on the system that the bridge is part of, the rapidity of MoDOT to fix the bridge, and other repair aspects. MONTANA DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Montana, scour, wind, landslide, and flood and debris flow are extreme events highly likely to cause damage to bridges. Fire is considered a likely event to cause damage to bridges, as well as possible earthquakes, over-height collisions, ground acceleration, and liquefaction. Structures Rapid Damage Detection Techniques The most common form of damage detection used by the Montana DOT is visual inspection. Photogrammetry is used primarily to track flood progression and to predict where a flood may go, and what possible damage it may cause. The agency also uses inclinometers for regular bridge monitoring that are most often used during flooding season. State Hydraulic Engineer Montana DOT has determined that flood and debris flow is an extreme event highly likely to cause damage to bridges. Damage to bridges from scour is also considered to be possible. Hydraulics Rapid Damage Detection Techniques Montana DOT uses visual inspection as its primary form of rapid damage assessment. Buried or driven rod devices (e.g., a magnetic sliding collar), fixed sonar surveys, and underwater dive inspection are all additional techniques used by the agency to complement its visual inspections. These methods have proven to be capable of providing sufficient data for bridge damage assessment after an extreme hydraulic event. Often the data collected cannot be utilized immediately because Mon- tana DOT relies substantially on visual inspection, survey, and potentially divers. Emergency Response Procedure The maintenance of structures is necessary for the public safety, structural integrity, and protection of the state’s capital investment. Maintenance and repairs of a structure include: • Repairing damage or deterioration in various bridge components; • Removing debris and drift adjacent to piers; • Tightening or replacing bolts and nuts; • Repairing bridge deck surfaces; • Adjusting bridge height after a settlement; and • Repairing vehicle impact damages to beams and columns. The general procedures for repairs are as follows: 1. Consult or coordinate the repair with the bridge main- tenance engineer 2. Obtain any required permits or access permissions 3. Ensure that materials and required specialized equip- ment are available before starting work 4. Set the traffic control devices 5. Perform required maintenance and repairs for the spe- cific job 6. Clean up the area 7. Dispose of debris and material appropriately 8. Remove traffic control 9. Report repair to the District Bridge Inspection Coordinator. NEW HAMPSHIRE DEPARTMENT OF TRANSPORTATION State Hydraulic Engineer New Hampshire DOT (NHDOT) has determined that scour, storm surge and waves, and flood and debris flow are all extreme hydraulic events that are considered highly likely to occur. NHDOT has a scour POA for all scour critical bridges. Hydraulics Rapid Damage Detection Techniques NHDOT uses visual inspection as its primary form of rapid damage detection. NHDOT also uses drop-line readings for channel profiles. The agency relies heavily on bridge inspector expertise to report findings during post-flood bridge inspec- tions. Member alignment and signs of settlement are checked. NHDOT has limited experience with higher-tech methods, but has found most to be highly unreliable for the long-term applications.

41 Emergency Response Procedure NHDOT is working on being able to predict floods by using the information provided by its regional forecast center in Gray, Maine. NWS flood warnings are typically issued by county or by major river and watershed. When there is an active flood warning, the bridge inspectors are placed in stand-by mode and sometimes even dispatched to scour critical bridges in advance of the predicted flood. Many of New Hampshire’s scour critical bridges cross rivers that are monitored by USGS stream gages, and the forecast hydrographs are studied by NHDOT engineers and person- nel at New Hampshire’s Transportation Management Cen- ter (TMC) to determine if projected flows will approach or exceed scour critical flows. Once a bridge is actively being monitored, the inspectors follow the bridge scour POA. If a bridge is not experiencing scour flows and is determined to be functioning properly, the bridge will remain open to traffic, but may be revisited if rain intensifies or if the stream gage shows that the water level is rising. If the bridge is found to have flood-related distress threatening safety and/or service- ability, the bridge is immediately closed to traffic. This deci- sion would typically involve the nearest NHDOT district offices and would involve requesting the installation of bar- ricades and signage to create a suitable closure and detour. There is a TMC in place that works closely with police and the media to make sure road closures and emergency situa- tions are distributed through their different media outlets. It monitors road closure status, keeps an inventory of closures, and monitors the emergency until the situation is stabilized. In the event of an extensive flood, such as the one with tropi- cal storm Irene, the DOT activates its EOC, which is a multi- discipline room of individuals who are experts in particular subjects (e.g., a bridge representative, highway representative, TMC representative, police representative) to respond to the possible raising issues. NEW YORK STATE DEPARTMENT OF TRANSPORTATION State Bridge Engineer New York State DOT (NYS DOT) has determined that vehi- cle bridge collisions occur at the highest frequency. Extreme events involving damage to bridges from scour, wind, land- slides, flood and debris flow, fire, and liquefaction hazards occur at low frequency, with scour and collisions having the highest likelihood of damages to bridges in the state of New York based on historical data. Structures Rapid Damage Detection Techniques NYS DOT uses a variety of techniques for the rapid damage detection of bridges. Visual inspection is the primary form of damage detection used by the agency. Methods such as sonar surveys, hand-held NDT, GPR, and 3D laser scanning are used as needed. The NYS DOT believes that these damage detection techniques are capable of providing sufficient data for bridge damage assessment after an extreme event. NYS DOT has always been able to obtain the required data for damage assessment using available techniques. NYS DOT has established bridge vulnerability assess- ment programs for scour, seismic, collision, concrete details, and steel details. In recent years, working with researchers, NYS DOT has developed post-seismic bridge assessment guidelines that are under consideration for adoption. Fig- ure 20 shows a comparison of the different types of bridge damage assessment techniques for dealing with earthquakes, with the most immediate type of assessment on the left and the more time- and labor-intensive ones on the right. Emergency Response Procedure NYS DOT has created post-earthquake bridge inspection guidelines that are under consideration for adoption. The per- formance of a bridge structure under earthquake excitation is influenced by hazard factors (e.g., magnitude, direction of waves, and proximity to epicenter), site conditions (e.g., the type of underlying soil supporting the structure) and response factors, such as structure type, material, structural details (e.g., connections, foundation fixity, and reinforcement details), and condition (e.g., deterioration from rust). Within the guidelines, there are potential bridge damages and the possible causes that would result from an earthquake (Figure 21). The earthquake response plan that NYS DOT is consider- ing for adoption has three levels of response, depending on the magnitude of the earthquake (Figures 22 and 23). According to the guidelines under consideration, the Resi- dential Engineer (RE) is responsible for initiating the Pre- liminary Bridge Damage Assessment (PBDA) program in the event of an earthquake, managing and supporting staff in its execution, working closely with the Regional Structures Engi- neer (RSE) to implement closures or to take other actions, and communicating with other DOT managers. A PBDA is a quick condition assessment of a bridge obtained by residency staff during a route reconnaissance within a few hours of an earthquake. It is a cursory visual inspection, with the primary objective being to identify and close any unsafe bridges. The team is expected to stop at each bridge and look for any damage that might have been caused by the earthquake. The steps for the RE executing the PBDA are as follows: 1. Provide earthquake awareness training to residency staff, on an annual basis. 2. Ensure that resources needed for earthquake response are ready for deployment at any time. 3. Personally subscribe to the Earthquake Notifica- tion Center and assign this responsibility to next in command.

42 4. Maintain a map and/or list of priority routes in the residency. 5. Maintain a map and/or list of all bridges in the resi- dency, with an identification of bridges considered most critical. 6. Immediately commence PBDA on all routes in the residency whenever: a. The epicenter of the earthquake is within the radius of concern of any part of the residency. (The radius of concern varies according to the earthquake magnitude.) b. There are reports of earthquake damage to bridges, buildings, or slopes within the residency. 7. Deploy two-person PBDA teams. 8. RE responds to questions from field teams and pro- vides any necessary support. 9. Collect and review daily reports from field teams. Summarize findings and send a daily report to RSE with digital photos of any damage. Provide the data electronically (i.e., in a spreadsheet), if possible. 10. Verbally report any significant bridge damage to the RSE immediately. 11. Immediately close and barricade any bridges that appear to be unsafe. 12. If there is any uncertainty about a bridge’s condition, request that the RSE conduct a bridge inspection (Special Post-Earthquake Bridge Inspection: SPEBI). 13. After SPEBIs are completed, close or reopen bridges as requested by the RSE. 14. Arrange for immediate repair of damage that does not require any analysis (e.g., damaged approach). Document all activity with photographs and inform RSE. The RSE in the affected area is responsible for com- pleting all necessary detailed inspections in an expedi- tious manner, with an effort that is commensurate with the severity of the event. The RSE will also direct follow-up action such as conducting detailed inves- tigation, structural or geotechnical analy sis, design- ing repair of retrofit schemes, or initiating long-term replacement or rehabilitation. The main goal of a SPEBI is to assess the structural integrity of a bridge after an earthquake, with the focus being on the assessment of its seismic performance. The SPEBI process is as follows: 15. Annually provide earthquake awareness training to bridge inspectors and other staff who might be called into service after an earthquake. FIGURE 20 Types of post-earthquake bridge damage assessment techniques.

43 16. Ensure that resources required for an earthquake response are ready for deployment at any time. 17. Personally subscribe to ENS. 18. Communicate with regional GIS and emergency response staff and share data that are required to maintain a current: a. Map and list of priority routes in the region that can be used as lifeline routes. b. Map and list of all bridges in the region, with an identification of bridges considered most critical, those that are flagged and, if possible, those con- sidered seismically vulnerable. c. List with emergency contact numbers for bridge inspectors and office staff who may be involved in post-earthquake response. 19. Notify local county highway superintendents, authori- ties, and other bridge owners whenever any significant earthquake occurs and advise of appropriate action. 20. Refer to Earthquake Response Plan; determine which response level and radius of concern is appropriate and communicate to others. Organize bridge inspec- tion teams and commence SPEBIs, preferably within 8 hours. 21. Generate a prioritized list of bridges to inspect and print GIS maps with the locations of these bridges. Provide maps to bridge inspection teams. 22. Inspectors are to submit Daily Summary Reports at the end of each day when SPEBIs are completed. Collect and review daily reports from field teams. Summarize findings and send a report to the Regional Director and the Director of Office of Structures, the Incident Commander and Statewide Transportation Information Coordination Center as appropriate. 23. Review SPEBI reports. Determine if any bridges should be closed or restricted (weight restricted, reduced number of lanes, or open to just emergency vehicles). Provide authorization to reopen bridges that were closed as a precaution during the PBDA phase if it is appropri- ate to do so. Track resolution of any structural flags. 24. Prepare plans for repair, retrofit, or replacement as appropriate and work with structures asset manage- ment team to program remedial work. FIGURE 21 Potential bridge damages.

44 25. Defer any communication with the media to the RD’s designee. OHIO DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Ohio, over-height collisions are the extreme events with the highest likelihood of happening. There is also a possibility of damage to bridges from scour, wind, lands lides, flood and debris flow, fire, ground acceleration, and liquefaction. Structures Rapid Damage Detection Techniques Ohio DOT uses visual inspection primarily when assessing damage to bridges. If there is reason to believe that there may be more wrong that is not visible, typically magnetic particle testing or dye penetrant testing is used on the structure. Emergency Response Procedure Ohio DOT primarily uses two different repair processes. A Type A emergency repair process is used when an emer- gency is declared and it is necessary to deal with damages immediately. A contractor is then called and met at the job site. No plans are created beforehand; the repair process is determined on site. A Type B emergency repair process is used when an immediate response is not necessary. A set of plans is prepared and three contractors are notified. An expedited bid opening and award process is used to select which contractor will work on the designed plan. The res- toration process usually begins the following day, but could happen as early as the day of the extreme event. The great- est source of delay is acquiring approval to declare a Type A emergency. OREGON DEPARTMENT OF TRANSPORTATION State Bridge Engineer In Oregon, there is a high likelihood for bridge damage caused by scour, wind, landslides, flood and debris flows, and over- height vehicle collisions. It is likely for earthquakes, storm and surge waves, ground acceleration, and liquefaction to cause damage to bridges as well. There is also a possibility of blast and fire damage affecting the bridges. FIGURE 22 Response levels in the NYSDOT earthquake response plan.

45 Structures Rapid Damage Detection Techniques Oregon DOT’s most common form of damage detection is through visual inspection. Additionally, accelerometers, velocity meters, and NDT are used for damage detection. The accelerometers and velocity meters have only had limited use. They are used in areas with high wind vibrations on long- span bridges and have been effective. They have been able to characterize responses of the bridge members on long-span trusses to help identify reasons for fatigue cracking. Oregon DOT uses NDT techniques on occasion. The time frame that the monitoring data are integrated into post-event damage assessment is believed to have room for improvement. Currently, all interpretation and evaluation is done independently, by hand. An investment in a comput- erized system that would help to analyze the collected data and produce results more rapidly would be preferred. Oregon DOT is developing a system that tracks rainfall, river gage heights, weather predictions, and several scour monitoring devices, which can be used to predict high water and scour and monitor the specific bridges that are then determined to be at risk. This system has not had an oppor- tunity to work because there has not been flooding in areas where it has been implemented. Oregon DOT has 12 bridges instrumented for seismic activities. Oregon is at high risk for dealing with a seismic event, but has not experienced any extreme events; therefore, this system has so far had limited use. State Hydraulic Engineer Oregon DOT has determined that storm surge and waves and flood and debris are both extreme hydraulic events that are likely to occur. There is also a possibility of scour and tsunamis. For most structures, the agency’s policy on how to respond to hydraulic events is to have maintenance personnel do a visual inspection of the affected structures. On bridges that are con- sidered to be scour critical, Oregon DOT will follow up with soundings at the bents after a large storm event. Hydraulics Rapid Damage Detection Techniques Oregon DOT’s primary method of damage detection follow- ing an extreme event is visual inspection. It also uses sound- ings to check on scour critical bridges. These methods have been able to provide sufficient data for bridge damage assess- ment; however, the agency is looking for more robust scour monitoring devices that can be used during an event. Emergency Response Procedure Oregon DOT has developed an Emergency Operations Plan with a specific section on bridge damage assessment to provide a list of personnel expectations and actions when a major event involves bridges in the state. In such events the Oregon DOT bridge section will dispatch an inspection coordinator to help coordinate the bridge inspection activi- ties at the incident command center located in the affected area. Bridge damage assessments and emergency bridge repairs will be made as directed by the inspection coordi- nator. All bridges in the affected area will be inspected by Oregon DOT. Bridges will be closed as necessary to protect the public. The agency will perform Level I, Level II, and Level III inspections as needed. Level I inspections are performed by Oregon DOT to assess the extent of bridge damage. Those performing the Level I inspections will take any necessary immediate actions to protect the public. Level I inspections on all bridges in FIGURE 23 Process flowchart for earthquake response plan.

46 the affected area are to be completed within 24 hours of an extreme event. Although all structures in the affected area will be inspected, the importance of inspections will be con- sidered in the following order: (1) lifeline routes (a route that is used to provide essential services during the first 72 hours following an event), (2) lifeline alternate routes, (3) interstate routes, (4) major aerial routes, and (5) secondary highways. This level of inspection will only assess whether the structure is to remain open or be closed. Level II inspections are performed by a certified bridge inspector or a licensed civil or structural engineer in the state. This is a more in-depth damage assessment that may include recommendations for temporary repair or shoring. As a safety precaution, it is anticipated that bridge engineering section personnel will be teamed and deployed with District bridge maintenance personnel. The objective of this team- ing is to maximize the expertise of the personnel, familiarity of the affected area for potential detour routes, and to exercise the delegated authority for closing a structure. Upon comple- tion of the inspection, these inspectors will take the follow- ing actions: (1) notify the bridge inspection coordinator as to the status of the bridge, (2) mark the bridge ends in accor- dance with the standard procedure, (3) complete an emergency bridge inspection report form on each structure inspected, and (4) forward a copy of the bridge inspection report to the bridge operations engineer. A Level III inspection can be requested if deemed neces- sary by the personnel performing the Level II inspection. The Level II inspections on all bridges in the affected area should be completed within 72 hours of the event. Level III inspections are conducted after all bridges within the affected area have been initially inspected and actions have been taken to ensure their safety. The Oregon DOT bridge section will assign forensic investigation teams to handle these more detailed inspections. The purpose of this in-depth inspection is to perform an on-site analysis of the damaged portion of the bridge, which could include NDT testing of the primary structural members. It is anticipated that a Level III inspection will only occur on selected structures that warrant a detailed inspection. TENNESSEE DEPARTMENT OF TRANSPORTATION State Hydraulic Engineer Tennessee DOT (TennDOT) has determined that the most likely extreme hydraulic event to occur that would cause dam- age to bridges is scour. Flood and debris flow is also considered a possibility. Hydraulics Rapid Damage Detection Techniques TennDOT uses visual inspection as its primary form of rapid damage detection following an extreme hydraulic event. Por- table sonar surveys, as well as probing and underwater cam- eras, are also techniques used in the rapid damage assessment of bridges. The data collected from these techniques cannot always be immediately used to assess the extent of damages after an extreme hydraulic event. When this is the case, visual checks of a bridge are made for any misalignments. At this time the bridge may be closed to traffic until water levels fall and a more in-depth inspection can be made. TennDOT believes that its current damage detection techniques are capable of providing sufficient data for bridge damage assessment after an extreme hydraulic event. Side-scan sonar imaging is a damage detection technique that TennDOT believes is capable of identifying damage more rapidly and reliably. It can only be used when the water is 10 m deep or deeper. The sonar takes an image of the pier underwater and another one above water. The two images are then combined by a computer program to give a complete image of the pier from its foundation to the top. Sonar is con- sidered to be useful for deep water conditions as divers can only stay underwater for a set amount of time. Sonar provides divers with specific locations to focus on. Emergency Response Procedure TennDOT uses the BridgeWatch system to monitor scour critical bridges, potential storms, and flooding. The auto- mated monitoring application provides alerts to potential critical events based on comparisons of real-time weather and hydraulic data with thresholds and information previ- ously uploaded in the application. TennDOT uses the bridge inspection program procedure manual, which outlines the general practices and procedures used to inspect and evalu- ate bridges in Tennessee. WASHINGTON STATE DEPARTMENT OF TRANSPORTATION State Bridge Engineer Washington State DOT (WSDOT) has determined that scour, wind, storm surge and waves, landslides, flood and debris flow, and vehicle collisions are all events likely to cause damage to bridges, followed by earthquakes and fire. Structures Rapid Damage Detection Techniques WSDOT uses visual inspection as its primary damage detec- tion technique, coupled with NDT techniques on a regular basis. Emergency Response Procedure WSDOT has a critical damage bridge repair report (CDBRR) form that was developed by the state to assist in documenting

47 and tracking critical structural and safety-related deficiencies on damaged structures (Figure 24). WSDOT has a relative guide on determining when a CDBRR is required. Most damage inspections do not require a CDBBR. The most common cases are related to vehicular impact damage. In such instances, a damage inspection report is completed that includes: (1) the listing date and location of the incident, (2) description of the incident, (3) brief description of damage to the structure, and (4) brief description of anticipated repair recommendations. WYOMING DEPARTMENT OF TRANSPORTATION State Bridge Engineer Wyoming DOT (WYDOT) has determined that scour and wind are the extreme events with a high likelihood of occurrence, FIGURE 24 Field inspection procedure.

48 followed by earthquake, landslides, flood and debris flow, and over-height vehicle collisions. Structures Rapid Damage Detection Techniques WYDOT uses visual inspection as the primary approach for damage detection. Another technique that is used to cover large areas of damage is photogrammetry by means of aerial photos. This method has proven to be an effective and quick way of assessing locations of possible damage to roadways and structures. Emergency Response Procedure WYDOT has documented special procedures to respond to flood emergency conditions. Flood warnings are issued by the NWS and transmitted through weather service radio or other media. When there is a flood notification, the bridge monitoring procedures are triggered. Once the water surface elevation reaches or exceeds the estimated high-water eleva- tion, monitoring of the streambed and stream banks begins. If the bridge is defined as scour critical, the monitoring and closure procedures noted on the POA should be followed. The monitoring crew looks for signs of bridge distress before accessing the bridge and throughout the high-flow monitor- ing effort. These signs include but are not limited to over- topping of the bridge, vertical or lateral displacement of the bridge superstructure, excessive horizontal or vertical separation of bridge joints, visible damage to the bridge or substructure, sinkholes in roadways behind the abutments, and massive debris build up. If any signs of bridge distress are apparent at that time, the inspection crew calls for a bridge closure and avoids accessing the bridge if at all possible. An inspection crew may decide to close a bridge if any of the following conditions occur: the bridge shows clear signs of distress, the streambed has lowered to the scour critical elevation at a pier or abutment, previously installed scour countermeasures are judged to be failing under high flow, or a bridge is already under severe hydraulic conditions and it is communicated to the crew that a higher wave is approaching from upstream. The high-flow monitoring crew may find it necessary to call for emergency protection, such as placing rock riprap to slow or arrest scour at a pier or abutment, or to stabilize an eroding river bank. Once the flood warning has lifted and water has receded, the district engineer will contact the state bridge engineer to schedule follow-up inspections. Once damage is properly assessed, the bridge program will provide repair recommenda- tions to the district for use in developing a repair project or to direct state maintenance forces to perform the repairs. Repairs should be completed as soon as possible after the event. NEW YORK CITY DEPARTMENT OF TRANSPORTATION City Bridge Engineer New York City DOT (NYCDOT) has determined that extreme events involving wind, storm surge and waves, and flood and debris flow are highly likely to cause damage to bridges. Scour is considered likely to result in bridge damage, and earth- quakes and floods are a possibility. Structures Rapid Damage Detection Techniques NYCDOT uses a number of rapid damage detection tech- niques to complement visual inspection. They use SRS, accelerometers, tilt meters and inclinometers, fiber optics, anemometers, and a scour monitoring system that is used to measure several parameters including flow speed and depth. NYCDOT believes that the damage detection techniques currently in use are capable of providing sufficient data for bridge damage assessment; however, they believe that there is always room for enhancement and integration of the detection techniques for different hazards. There are cur- rently no on-line systems that are capable of replacing visual inspections. One lesson that NYCDOT has learned is that whenever possible, the planning for the response must begin before the event. This also includes the hazard mitigation strategies (preventive actions). One preventive measure that the agency has implemented in their hydraulic vulnerability manual is in relation to bridges susceptible to scour damage. In this case, the use of stone fill (rip rap) has significantly increased the protection to bridges that are susceptible to scour damage. Emergency Response Procedure NYCDOT has an Office of Emergency Management. This agency plans and prepares for emergencies, educates the public about preparedness, coordinates emergency response and recovery, and collects and disseminates emergency infor- mation. After an extreme event resulting in bridge dam- ages, NYCDOT immediately assigns emergency teams to do inspections. DEPARTMENT OF TRANSPORTATION: LOS ANGELES COUNTY County Bridge Engineer Los Angeles DOT has determined that fire is highly likely to cause damage to bridges during an extreme event. Vehicle collisions are also considered to be likely, as well as earth- quakes, scour, flood and debris flow, ground acceleration, and liquefaction.

49 Structures Rapid Damage Detection Techniques Los Angeles DOT uses visual inspection as its primary form of rapid damage detection. The agency also implements a system called ShakeCast, which is a software system used by the DOT to retrieve measured shaking data within min- utes of an earthquake. It compares shaking distribution with unique bridge vulnerabilities and provides hierarchical lists and maps of bridges most likely to be impacted. This leads to a faster bridge inspection response. The use of ShakeCast and visual inspections has proven to be capable of providing sufficient data for bridge damage assessment. Los Angeles DOT is aware of other techniques that could assist in bridge damage assessment such as sensors that can be placed on bridges to monitor movements and stress and strains. Emergency Response Procedure In the instance of a seismic event, Los Angeles DOT follows the procedures in the earthquake bridge inspection manual. The automatic activation of personnel is required if the earthquake is significant enough. The primary measures immediately fol- lowing an earthquake are to inspect bridges and provide rec- ommendations for opening and closing bridges to traffic. For nonseismic events, the county has a 24-hour dispatch system that will alert any needed road and bridge personnel. Synthesis of Emergency Response Planning From a review of the extreme events that have impeded the performance of bridges and the service of the transportation networks it is evident that the competing demands; limited budgetary, human, and technical resources; and the urgency of restoration in capacity of the system underscore the impor- tance of planning. This will reduce delays in response and helps to avoid conflicts at a chaotic time. The establishment of repair and replacement priorities before the event will help guide decision making during the response and recov- ery process and will minimize any unintended consequences. With such an approach, the decision-making authorities, law makers, and response and recovery teams will all be working toward the established goals. Having a streamlined plan for response and recovery will also help to organize teams in a more efficient way to respond to extreme events that were not necessarily foreseen in the original plan, as it provides them with a hierarchy of actions to be taken. To have an effective planning tool, it is important that the process of response and recovery be prioritized. This process would include the following steps: • Assessment of damage to the transportation network at the component and network levels and identifica- tion of the roadways and links that will most likely be damaged. For this purpose, a detailed hazard char- acterization process and vulnerability assessment of the transportation systems both at the component and network levels is required. The outcome of this analy- sis will highlight the nodes and links of the network that are most likely to fail as a result of the considered events. • Prioritization of the response and recovery actions for damaged assets. At this stage, critical facilities such as hospitals and police stations that need to be con- nected to transportation resources immediately after an event are identified and prioritized. Then the results of the previous step are to be weighed based on the importance to the performance of the system. Here different performance measures such as travel time and short-term and long-term economic impacts could be considered. • Plan for a balanced portfolio of actions that could result in achieving the set goals for response and recovery. This will include (1) implementation of strategies to identify the extent of damage as immediately and accu- rately as possible (training of on-site inspectors, use of health monitoring data, use of remote sensing tech- nologies), establish a clear line of communication with the inspection team, and provide detection devices at the headquarters of transportation agencies; (2) create regu- lar training sessions for the response and recovery teams that would keep them up-to-date on the most recent organizational aspects of response, recent technolo- gies, and protocols. Appointments to the response and recovery teams are to be identified prior to the event so that members of the team can understand their role in the response and recovery process and the actions they are expected to perform during this period. This team may include transportation planners, structural engi- neers, emergency management experts, environmental experts, and first responders. It is important that the team include members that have experience responding to disasters. The location of resources is identified with respect to potential risk areas and the pathways to sup- ply materials, instruments, and work force to such areas optimized. • The different response and recovery approaches would consider the component of time in addition to cost– benefit analysis to ensure the selection of the most effec- tive recovery actions that are conductive of a resilient response. Figure 25 in chapter five provides a review of such approach.