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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
×
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
×
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
×
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Suggested Citation:"Chapter 5 - Assessment Process." National Academies of Sciences, Engineering, and Medicine. 2016. Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual. Washington, DC: The National Academies Press. doi: 10.17226/24610.
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41 C H A P T E R 5 5.1 Assessment Stages Highway structures will be assessed during an emergency situation using a four-stage pro- cess: Fast Reconnaissance, Preliminary Damage Assessment, Detailed Damage Assessment, and Extended Investigation. The primary scope of this document is to address the FR and PDA stages. The DDA and EI stages will generally be completed using standard structural inspection operating procedures that reflect the specific needs and approach of each SHA. Hence, these stages will be briefly introduced, but detailed methodologies will not be presented herein. These four stages, described in the following sections, are based on methods currently in use throughout the United States (ATC 1995, 1; O’Connor 2010; Reed and Wang 1993). This multi- tiered approach is aimed at making best use of the limited resources with the appropriate skill and expertise, while maximizing assessment rates and providing redundancy to the process in order to maximize safety. Figure 5-1 diagrams the assessment process for a single structure and the interaction of the assessment stages along with the possible marking classifications for a structure. The marking classifications are described in detail in Section 6.1. Table 5-1 summarizes the objective and primary deliverables of each assessment stage. 5.1.1 Fast Reconnaissance The objective of the FR stage is to quickly provide a global perspective and to establish/update the extent of the damage region as necessary. This work needs to be completed both in the office and in the field. While FR should be completed at all response levels (see Section 5.2), the type and detail of FR will depend heavily on the size of the event. A basic FR should be completed within 4 to 6 hours of the event. Descriptions of five possible FR methods follow: • Pre-event or real-time disaster hazard mapping products. For several major emergency events such as earthquakes or hurricanes, pre-event or real-time disaster hazard map- ping are often available, which provide the most rapid information indicating potentially severely damaged areas. When available, this information should be used; however, the start of the response process should not wait for this information because the timeliness of the data can vary. • Rapid remote sensing. Aerial imaging and lidar reconnaissance using helicopters or small fixed-wing aircraft that can quickly be mobilized are most appropriate for higher response levels. For lower response levels, personnel can be designated to drive highway routes (with- out stopping) to determine the nature and extent of the damage. These crews can utilize global positioning system (GPS) technology to log their routes and document where damage is observed. Assessment Process

42 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual • Crowdsourcing. Live video from SHA cameras or other sources, such as the media or the general public, may be used for an initial assessment on the condition of severely damaged structures. • Small or micro unmanned aerial vehicle (UAV) based imaging is being considered currently and expected to become a popular approach for hard-to-access disaster areas. Similarly, auto- mated analysis using technologies such as mobile lidar may be used for a quick assessment of the landslide potential of slopes and embankment settlements. • Detailed FR techniques such as aerial reconnaissance (e.g., helicopter or small fixed-wing aircraft) is strongly recommended only for larger events (e.g., Response Level IV), where the damage is likely to be geographically dispersed. The information from these technologies can then be combined into a GIS platform where structure databases can be cross-correlated with the incoming damage reports from FR. Inspec- tion routes and priority lists can be updated frequently using this real-time information. Any of these FR methods are useful to quickly assess multiple structures within a region and to help inform the prioritization of ground assessments. This information should also quickly be fed to traffic engineers who can identify and create appropriate detour routes, minimizing traffic congestion problems that can lead to accidents or slow recovery efforts. 5.1.2 Preliminary Damage Assessment The PDA stage is performed immediately following an incident, likely within hours, to pro- vide information on the need for action such as road or bridge closures and to define immedi- ate remedial action if needed (see Figure 5-1). It is expected that this stage may take from a few minutes to 30 minutes per structure depending on the type of structure, degree of damage, and accessibility constraints. The on-site PDA will be conducted by PDARs who will use digital cameras or other mobile devices to take pictures, preferably geo-tagged, and make brief written reports of their observations on each structure. PDA photos and reports will be uploaded into an emergency inspection management system or agency equivalent. If connectivity is available during the emergency incident, uploading will occur remotely at the site; if not, this will occur upon return to central command. This type of assessment includes preliminary percent damage PDA LIMITED USE UNSAFE DDA UNSAFE INSPECTED EI Repair/ Rebuild INSPECTED UNSAFE (Partial/Full Collapse) Emergency Situation Primary Scope of NCHRP Project INSPECTED Preparation UNSAFE = The structure requires further evaluation in the next assessment stage prior to being open to traffic. LIMITED USE = Potentially dangerous conditions are believed to be present and usage is restricted to ensure public safety. INSPECTED = The structure appears to be in the same condition as it was prior to the event. No Collapse FR Figure 5-1. Assessment stages and subsequent primary level of coding.

Assessment Process 43 estimates of the structures, which are used for prioritizing DDA. These estimates also could be used to develop preliminary damage cost estimates for the incident that can be refined with DDA and EI. It is strongly recommended that a DDA be performed by trained inspectors for every structure that could potentially be damaged by the event despite the decision of the PDA. However, those that are not found unsafe during the PDA can be given a lower priority for the DDA and completed at a later time. Given the wide variety of damages observed in various types of emergency events, it can be overwhelming to check for every possible type of damage on every element. To simplify the process, the most common types of damages seen throughout the various emergency events are grouped into categories of structural, geotechnical, hydraulic, and special case (see Table 5-2). Fast Reconnaissance (FR) Preliminary Damage Assessment (PDA) Detailed Damage Assessment (DDA) Extended Investigation (EI) Objective Global perspective Rapid route reconnaissance Detailed inspection Special study to address a particular concern Scope All structures in affected area All structures in affected area, starting with priority routes Structure and site specific Site specific, as needed Inspection Method Helicopter, small fixed-wing aircraft, UAVs, and other “fast” methods Drive-through with quick stop at each structure Inspection and special access equipment as needed, load rating and remaining strength analysis Any special equipment that is needed Personnel Chief engineers or managing engineer in aircraft or vehicle; specialized technicians as needed; the public PDARs—Trained emergency responders (maintenance & operations crews, design engineers) Routine inspectors and specialists (e.g., structural, geotechnical, hydrological, mechanical, materials) Specialists (e.g., structural, geotechnical, hydrological, mechanical, materials) Time Frame Immediate (within 4–6 hours) Immediate (within 24 hours) Start ASAP (usually within 8 hours) and continue as necessary Subsequent to DDA Outcome Determine the geographic extent of damage Identify impassible routes and traffic bottlenecks Locate structures that have major damage or are obviously unsafe Suggest priority for ground assessments Determine the extent and type of damage Identify/confirm impassible routes and traffic bottlenecks Close unsafe structures Code and mark Recommend DDA for damaged or suspect structures Preliminary damage level estimate Code and mark as necessary Close unsafe structures Recommendations for restriction, repair, or further investigation Preliminary cost estimates for agencies such as FEMA Reopen structures deemed safe that were closed as a precautionary measure during PDA survey Damage level estimate Code and mark as necessary Detailed damage analysis Provide specific recommendations on necessary restrictions and/or repair Approximate cost estimate for remedial work Deliverable Reconnaissance report with maps, geo-referenced photos, and/or video that defines the affected region Digital PDA form/ database (one entry per structure) and physical marking on the structure DDA report for each structure and daily summary report Special engineering report Coding Options UNSAFE UNSAFE, INSPECTED UNSAFE, LIMITED USE, INSPECTED UNSAFE, LIMITED USE, INSPECTED Source: Modified from O’Connor (2010). Table 5-1. Damage assessment stages.

44 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual The PDA should be conducted by a team of at least two PDARs. The following list outlines the general PDA procedure to be used for all structures: 1. Upon receiving notification of an emergency event, PDARs review vulnerabilities and com- mon damages for highway structures. 2. PDARs assist in rescue efforts, if necessary. 3. If any hazardous condition is encountered during the inspection, such as downed power lines, faulty traffic control devices, or roadway obstructions, the appropriate authorities should be contacted in order to secure the area. 4. Prior to starting their route, PDARs confirm with each other the division of tasks. Generally, only one team member should fill out a single form for each structure. Both should make observations and be alert to the conditions of the scene. 5. PDARs approach the structure with caution and never walk or drive immediately under, over, or adjacent to the structure until the safety of the environment has been assessed. 6. Each PDAR should remain reasonably separated from each other but remain within visible range at the same time and never go underneath a structure at the same time. 7. When first arriving to a structure site, PDARs take a photograph of the identification tag, a photograph of the overall structure, and GPS coordinates. If available, the QR code on the structure should be scanned. With a smart device and app, these can be completed from the same device. 8. A site visit is estimated to take 15 to 30 minutes to complete. However, if the structure is clearly collapsed and unsafe, PDARs can simply complete the basic elements of the form and move onto the next site after notifying the managing engineer that the structure should be closed. More complex or larger structures will take longer to properly perform a PDA. PDARs should be conscious of the time and make sure that they do not spend too long at a particular site so they can efficiently move through their route. 9. A more detailed process for each structure is written in Volume 3: Coding and Marking Guidelines to help quickly walk PDARs through the process. When necessary, PDARs should consult the damage state lists and photographic examples provided in Volume 3: Coding and Marking Guidelines to aid in damage state ratings. 10. PDARs look for evidence of disturbance or irregularities such as shifts in guardrails or striping. These are noted on the form. Damage Type Damage Geotechnical Ground failure such as liquefaction, lateral spreading, landslides, etc. Slope instability Erosion Bearing capacity failure Active or passive failure Foundation settlement Structural Cracking and spalling of reinforced concrete members Flexural and shear failures of reinforced concrete or steel members Buckling, fracture, and tension failure of steel members Fatigue damage, including low-cycle fatigue Inelastic deformation and buckling Hydraulic Scour Debris impact Inundation leading to hydrostatic and hydraulic pressures Washout Special Cases Thermal expansion Reduction of strength and material properties due to thermal effects Efflorescence causing deterioration Decay of timber members Corrosion Table 5-2. Common forms of damage per type.

Assessment Process 45 11. PDARs provide an element damage-level ranking (none, minor, moderate, severe) for all applicable elements of the structure. 12. Once PDA is complete, the PDAR team meets and comes to a conclusion on the overall marking of the structure (INSPECTED or UNSAFE). 13. PDARs fix the placard to the structure in the appropriate location. Specific considerations for each highway structure are outlined in Volume 3: Coding and Marking Guidelines. 5.1.3 Detailed Damage Assessment The DDA stage is performed as soon as possible following an UNSAFE rating from a PDA, likely within 8 hours of the incident, if needed, and will continue as necessary to pro- vide an evaluation of structural damage level and decisions on use restriction, or the need for an EI (see Figure 5-1). This is a “damage inspection” as defined by the MBE and is not considered a rapid assessment for an emergency situation. It is therefore beyond the scope of this project. The DDA is included in this manual for completeness and to ensure the overall process is clearly defined as well as to ensure a smooth transition between the inspection stages. The DDA may include a load rating analysis to determine what levels and types of traffic the structure can safely handle. Information to support a load rating analysis includes the structure geometry, member connectivity, and section properties. The DDA is a multi-tiered inspection conducted by specialists (e.g., structural, geotechnical, hydrological, mechanical, materials) and may take several hours or more for each structure using integrated visual inspection and select technolo- gies. DDA photos and reports will be uploaded into an emergency inspection management sys- tem or agency equivalent. Note that DDAs should be conducted for all structures where damage was possible regardless of the outcome of the PDA. However, those with a PDA outcome of INSPECTED should be placed at a lower priority compared with those that were designated as UNSAFE. 5.1.4 Extended Investigation The EI stage is performed as soon as possible following an UNSAFE or LIMITED USE rating from DDA. This is an “in-depth inspection” as defined by the MBE and may also include a “special inspection” or an “underwater inspection.” The EI is not considered a rapid assessment for an emergency situation and is therefore beyond the scope of this project. The EI would also likely entail specialized technologies. Reporting of the findings from an EI follows the NBIS and other standard SHA operations. Although this stage is not within the scope of this project, this stage should be considered during planning and the DDA stage such that the process can transition from rapid emergency assessment into recovery and day-to-day operations. Follow-on inspections, emergency repairs, and testing would be conducted by more experienced professionals using more sophisticated technology than what the PDA and DDA would support. In the case of an earthquake, structures may survive the first event but become more vulner- able for aftershocks. Hence, continued monitoring and repeat checks may be needed. In most cases, these aftershock checks would involve a repeat of the PDA and DDA. Further, it is impor- tant to keep investigations in context of the longer-term safety and economic impacts so that the agency can integrate this with its priority ratings to determine when repairs and replacements should be made.

46 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual 5.2 Response Levels Responses levels relate to the immediacy of the response, the level of resources, and the effort that will be put into a response during an emergency event. They are essentially a status alert that can help ensure everyone is on the same page as to the magnitude of the response effort. As an example, a large earthquake (e.g., M7.0) creating damage over a dispersed geographic region will require a different method of response for structural assessment compared to a smaller event (e.g., M4.0 earthquake) where damages will be more localized and lesser in magnitude. Use of these response levels can help an SHA prioritize resource allocation, strategize their emergency response, determine which assessment stages are necessary, know when outside resources will be needed, and refine selection of inspection routes. Identifying these levels prior to the event will help improve coordination and communication of the response. This manual presents four response levels. Each SHA may determine the appropriate criteria for each level of response. During an emergency event, SHAs can decide to escalate or reduce a response level as more information becomes available. As an example, an SHA may choose the following strategy to help in their response: Level I Regular inspectors in the affected region(s) directly proceed to PDAs or DDAs, as appropriate. Teams are mobilized when the managing engineer determines that some damage has occurred based on FR observations. Level II SHAs complete PDAs with their maintenance crews and DDAs using inspection crews. Additional personnel such as design engineers are placed on call and mobi- lized to assist with PDAs when the managing engineer deems appropriate. Level III Inspectors focus directly on DDAs, while maintenance crews, design engineers, and others (as needed) in the region are immediately mobilized to perform PDAs. Inspectors from other regions could be placed on call to assist. External consul- tants from local firms who are appropriately trained could be utilized, as neces- sary. Federal assistance and coordination may also be required. Level IV In addition to the mobilization strategy in Level III, the SHA requests immediate assistance from inspectors, maintenance crews, design engineers, and external con- sultants from other regions to assist with the PDAs. Significant federal assistance and coordination will be necessary. It should be noted that the response levels defined in this manual are to be used as a reference or a guide for SHAs as they implement these recommended procedures for assessing, coding, and marking vulnerable structures. The selected values for magnitudes defined in each emergency event response can be refined depending on the SHA’s experience, local design practice, identifica- tion of vulnerable structures, and the intensity levels which have produced damage in past events. In addition, the response levels and their threshold values depend on the resources available and the experience of the SHAs with a specific emergency event. In certain cases, it may make sense for a specific SHA to add additional response levels or remove a level, if locally it is found to be a more reasonable approach. For example, SHAs in Alaska, Washington, Oregon, and California would likely use different earthquake magnitudes than those presented due to the higher level of seismic design standards and seismic activity. While it is important to be conservative in judgment when determining the appropriate response level, over-conservative calls to action may impede future efforts. If too many PDARs are allocated, this may lead to delays in design and construction for projects that will help improve resilience in the future and may be of a higher priority than the emergency event. False warnings and overemphasis can also numb people’s response to future events. Figure 5-2 provides a process flowchart for the emergency response following an emergency event. FR should be conducted for all response levels; however; it should be refined according to the

Assessment Process 47 ME = Managing Engineer Figure 5-2. Response level process flowchart.

48 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual severity and geographic extent of the emergency event. Upon receiving an emergency notification, emergency management officials should first validate it. Once the notification has been confirmed, structure priority routes should be reviewed and planned for inspection. Response levels corre- sponding with different emergency events are detailed in subsequent sections. For purposes of this manual, emergency events with similar characteristics were grouped together for simplicity when defining response levels. Therefore, response levels were defined for the following emergency events: • Earthquake • Tsunami • Tornado and high wind • Hurricane wind • Storm surge • Flooding • Fire 5.2.1 Earthquake Response Levels Magnitude and source-to-site distance are metrics that are highly correlated to the intensity of ground shaking. Other local effects, such as soil type in the vicinity and under the structures, and structure and foundation type, are also important parameters that affect the structure’s response. Nonetheless, both magnitude and source-to-site distance are well-accepted global metrics for deter- mining the extent of damage to which response levels can be tied. However, there are no absolute boundaries in an emergency incident and these intensity and distance metrics provide a starting point for mobilizing a response that can be refined as feedback becomes available from field crews. Table 5-3 illustrates the four response levels for earthquake events based on NYSDOT (O’Connor 2010). The intensity metric of the incident (i.e., earthquake magnitude) and the distance metric of the structure to the characteristic point (e.g., epicenter) are used in differentiating response levels. For example, for a M4.0 earthquake, the majority of the damage is anticipated to occur within a 40-mile radius of the epicenter. Given different seismic levels and seismic design standards, the magnitudes below are categorized by seismic design category. Several factors influence earthquake impacts; therefore, considerations are provided to better estimate the appropriate response level needed in the event of an earthquake: • The radius of concern should not be considered an absolute boundary during inspections. If any damage is observed outside of the given radius, increase the radius by 5 miles until no damage is found. • Site-specific intensity measures are useful parameters to determine the severity of damage. 5.2.2 Tsunami Response Levels The proposed tsunami response levels are based on NOAA’s warning system for Hawaii, which uses earthquake magnitude and location as proxies for tsunami intensity (NOAA/NWS 2014f). NOAA provides warning systems for the Pacific Ocean and the Caribbean Sea as well. Other parameters, such as local bathymetry, on-shore topography, and urban fabric, affect the maxi- mum inundation and tsunami flow velocities, which are highly correlated to the degree of damage. Although tsunamis may be caused by other geophysical phenomena such as volcanic eruption and landslides, for purposes of this process manual, the response levels will focus on the most common occurrence of tsunamis, which are typically triggered by significant magnitude earthquakes. Table 5-4 outlines the typical messages for Hawaii corresponding with earthquake magnitude and location. Tsunami messages include the message type (warning, watch, advisory); location; earthquake origin time, coordinates, depth, location, and magnitude; and evaluation (example in Appendix B.2).

Assessment Process 49 Several factors influence a tsunami’s impact; therefore, the following factors should be considered when determining a response level for a tsunami event. • Tsunami inundation and height is highly variable due to local topographic effects. Tsunami waves tend to concentrate in channels or areas of low slope surrounded by high hills, producing higher loads and inundation levels. • Damage will be extensive in flat, low-lying areas along the coast. Structures located in low, coastal areas surrounded by high cliffs are particularly vulnerable since the tsunami waves will concentrate in these channels. • Wave heights measured off shore can be much lower than what is seen on the coast due to amplification as water depths reduce closer to the coastline. • Prior to the tsunami reaching coastline, wave amplitude can provide an estimate to the antici- pated tsunami size. However, following the tsunami impact, actual inundation levels should be refined and used to determine appropriate response levels. • Initial impact from tsunami waves create only part of the damage. Wave recession and draw- down can take hours and generate additional loading on highway structures. Response Level Earthquake Magnitude Radius of Concern Description of Response SDC A/B SDC C/D I Mw < 3.5 Mw 5.5 na A broad-based response is not planned or required. If there are reports of damage, the managing engineer will determine if a PDA needs to be done. The managing engineer uses discretion to inspect especially vulnerable or critical structures close to the epicenter. II 3.5 Mw < 4.5 5.5 < Mw < 6.2 40 mi The managing engineer will immediately initiate PDA. All state routes within the residency will be driven according to priority and all structures investigated. Reports of damage or questionable conditions will be called in immediately. Summary reports are to be sent to the managing engineer at the end of each day. If no damage is discovered during PDA, the post-earthquake response can be terminated. DDA will be done on structures within the radius of concern: • Deemed critically important by the managing engineer • Following an UNSAFE rating from PDA • Where evaluation by a more trained or experienced person is needed If there are reports of structural damage outside of the default radius of concern, the managing engineer will increase the radius and adjust the inspection program accordingly. III 4.5 Mw < 5.5 6.2 Mw < 6.7 60 mi Use the same criteria as Response Level II, but with a larger radius. IV (High) Mw 5.5 Mw 6.7 80+ mi The state’s Incident Command System will be activated for this high-level response to ensure coordination of effort among SHA regions, main office, and other agencies. All available personnel should be mobilized. PDARs will conduct PDA of routes immediately and the managing engineer will arrange for DDA of all critical structures that are within the radius of concern as soon as possible. DDA evaluations should also follow the same criteria presented in Response Level II. SDC = Seismic Design Category Source: Based on O’Connor (2010). Table 5-3. Earthquake response levels.

50 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual • Local earthquakes of relatively lower magnitudes may generate a tsunami causing more dam- age than a larger magnitude earthquake with the epicenter farther away. • Runup and damage due to a tsunami are related to the phase of the tide when the tsunami impacts. 5.2.3 Tornado and High Wind Response Levels For purposes of this process manual, tornado and high wind events are grouped together for simplicity. High wind events are those with wind speeds ranging from 1 to 73 mph and are defined by the Beaufort scale (NOAA/NWS 2014d). High wind events are likely to occur over a local area with wind speeds varying by location. The NWS offers high wind watch/warning and wind advisory notifications (NOAA/NWS 2014g). All of the wind notifications are issued by local NWS Forecast Offices. Response Level Event and Message Type Earthquake Magnitude Tsunami Amplitude Description of Response I Local (Local Tsunami Information) 4.0–6.8 < 4 in. The managing engineer will monitor any cases of tsunamis reaching shorelines within the messages provided by NOAA. In the event of a tsunami, the managing engineer will initiate inspection of highway structures using PDA based on inundation levels. If it is confirmed that there is no tsunami reaching on shore, no highway structures need to be inspected unless there is strong ground shaking due to the earthquake. Distant (Tsunami Information) 6.5–7.8 II Local (Local Tsunami Information) 4.0–6.8 4 in.–3 ft NOAA warning messages will provide the location, coordinates, and arrival time of the estimated tsunami wave. Once a tsunami warning is issued, the managing engineer should plan PDA routes in the affected area. If there is confirmation that a region was hit by a tsunami, and only after the tsunami warning has been listed, the managing engineer will initiate PDA of highway structures. If no damage is discovered during PDA, the response can be terminated. As the inundation decreases from the coastline, structures should be evaluated based on the discretion of the managing engineer. In events of prolonged flooding, structures should be evaluated. Distant (Tsunami Advisory) 7.9 and ETA > 6 h III Local (Urgent Local Tsunami Warning) 6.9–7.5 3 ft–10 ft The managing engineer will monitor NOAA messages for the tsunami locations and arrival times. Inspections should only begin after the tsunami drawdown subsides. Tsunamis of this intensity are expected to occur over a vast area of coastline. SHAs may or may not have the personnel and resources to perform structural assessments. If there is a lack of resources, SHAs shall request assistance from federal agencies. Highway structures may have damage from not only the initial tsunami impact, but also the drawdown of the wave. Geotechnical and structural damage should be assessed using PDA of all highway structures located within the inundation zone. Distant (Tsunami Watch) 7.9 and ETA 3–6 h IV (High) Local (Statewide Urgent Local Tsunami Warning) 7.6* > 10 ft The managing engineer will verify affected coastal regions within NOAA messages. Detailed FR will take place to estimate the geographical extent of damage. Statewide tsunamis will likely impact all the entire state of Hawaii. All regions involved will activate the Incident Command System to ensure coordination with federal agencies. This event will require all available SHA inspectors, personnel, and resources. Distant (Tsunami Warning) 7.9 and ETA < 3 h ETA = Estimated time of arrival. *Local earthquakes with magnitudes higher than 7.6 have the potential to cause wave heights and/or inundation levels to exceed 30 ft. Table 5-4. Tsunami response levels for Hawaii.

Assessment Process 51 Tornados are classified by the EF scale and have wind speeds from 65 to over 200 mph (NOAA/ NWS 2014c). The EF scale rates the intensity of the tornado from EF-0 to EF-5 based on the damage of structures and vegetation on the tornado path. The official EF rating is often deter- mined after ground-based or aerial damage surveys which may occur a couple of days after tor- nados. However, preliminary estimates about the EF rating of a tornado and the size of affected areas can be made following inspection flights right after a tornado, which can help managing engineers to estimate the required level of response. Tornados themselves develop fairly quickly which makes it difficult to provide an accurate warning system. Table 5-5 outlines the proposed response levels for tornado and high wind events. High wind and tornado events can cause varying levels of geographic damage; therefore, the following con- siderations should be used when determining response levels. • High wind events will typically occur over a local geographic area whereas tornados will typi- cally follow a path. • Tornado events have the potential to cause large amounts of wind-borne debris. Although damage from wind may be minor, debris can cause severe damage. • EF ratings refer to damage at particular locations and not necessarily the damage over the entire tornado path or the size of affected areas. However, generally tornados with higher intensity can be expected to impact a larger area. When planning for the level of response, both the tornado EF rating and the size of affected areas must be considered. 5.2.4 Hurricane Wind Event Response Levels Hurricane intensity is defined by the Saffir–Simpson hurricane wind scale with wind speeds exceeding 74 mph (NOAA/NWS 2013). Hurricane wind events can occur over a vast region of land or be confined to coastline near the hurricane. Table 5-6 highlights the proposed hurricane wind response levels. Response Level Wind Speed (Scale) Length of Impact Description of Response I 32–64 mph (B7–B11) Local The managing engineer will monitor wind-prone structures in locations of wind speeds over 32 mph. These include overhead signs and cable bridges. PDAs will be performed at the managing engineer’s discretion. II 65–110 mph (B12–EF1)* < 10 mi In the event of high winds over 65 mph, the managing engineer will initiate PDA of wind-prone structures such as overhead signs and cable bridges. These structures should be inspected for damage caused by wind-borne debris. If an EF1 tornado occurs, the managing engineer will monitor all structures near the tornado path. The geographical extent of an EF1 tornado is difficult to predict but will typically take place over a few miles. SHAs should provide an adequate number of PDARs to perform PDA on all highway structures within the tornado path. III 111–165 mph (EF2–EF3)* 10–30 mi All highway structures located in the path of the tornado should be inspected. EF2 to EF3 tornados are likely to cause debris damage so the radius of inspection should be extended from Response Level II. The managing engineer will request federal assistance in the event of a large tornado event that taxes current personnel and resources. IV (High) > 166 mph (EF4–EF5)* > 30 mi All highway structures located in the path of the tornado should be inspected. EF4 and EF5 tornados are extremely violent and have the potential to lift large debris. It is likely that the radius of damage greatly exceeds the tornado path. The managing engineer will examine the extent of damage to determine an adequate extent of coverage for PDA evaluation. Federal assistance should be requested during EF4 and above tornados to adequately perform all necessary structure assessments. * EF ratings are not determined immediately after a tornado. These ratings are to be used only once verified after a tornado event. Table 5-5. Tornado and high wind response levels.

52 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual Once the event subsides and it is deemed safe, PDA evaluations should begin. Hurricane events can cause varying levels of geographic damage; therefore, the following considerations should be used when determining response levels: • The geographic extent of hurricanes is difficult to predict. The managing engineer should monitor the path and size of the hurricane to determine the extent of concern. • Hurricanes can cause wind damage not only along coastlines but far inland as well. • Hurricane events have the potential to cause large amounts of wind-borne debris. Although damage from wind may be minor, debris can cause severe damage. 5.2.5 Storm Surge Response Levels Storm surge often occurs over large areas of coastline and can damage highway structures due to repetitive wave loading. Table 5-7 highlights the proposed response levels for this pro- cess. Storm surge heights should be referenced with highway structure heights and in any cases where storm surge levels are expected to rise above the highway structure, the structures should be evaluated using DDA. Several factors influence the impact of storm surge, specifically coastal region. Therefore, the following factors should be considered when determining a response level for a storm surge event (Douglass et al. 2014): • Regarding bridges, most damage occurs when the storm surge elevations meet or exceed the height of the low chord of the bridge deck. • Damage can occur due to the impact of debris carried by waves. • Storm surge events can happen at any time during the year, not only during hurricane events. • Gulf of Mexico and South Atlantic Coast: – Coastlines with a shallow continental shelf can experience large storm surges. – Storm surge can vary substantially within the same estuary due to wind. – Storm surge wave heights are typically higher to the right of the landfall location. Response Level Wind Speed (Scale) Extent of Concern Description of Response I 74–95 mph (Hurricane Category 1) Local The managing engineer will monitor the development, progress, and location of the hurricane. The managing engineer will initiate PDA evaluation of all highway structures within the hurricane warning area. States affected should work in conjunction providing resources and personnel to any states in need. II 96–110 mph (Hurricane Category 2) Regional Prior to the hurricane making contact with land, the managing engineer should develop a list of critical highway structures within the defined hurricane warning area. As the hurricane develops, wind speeds should be collected and referenced with highway structures. III 111–156 mph (Hurricane Category 3–4) Statewide As the intensity of the hurricane increases to Category 3, a wider inspection radius should be used compared with Response Level II. This response level will follow the same criteria as Response Level II but with a larger radius. In the event of a widespread event, SHAs should request federal assistance for inspections. IV (High) > 156 mph (Hurricane Category 5) Multiple states In the event of a Category 5 hurricane, all SHAs affected should work in conjunction with federal agencies for necessary assistance. This event will likely be widespread and tax the resources and personnel of the local agencies in charge of structure assessment. It is recommended that a detailed FR be performed in order to estimate the geographical extent of damage. Highway structure locations should be monitored with wind speeds. Table 5-6. Hurricane wind event response levels.

Assessment Process 53 Response Level Storm Surge Height Description of Response I < 5 ft The managing engineer will monitor the development, progress, and location of storm surge heights. Storm surge maps should be developed highlighting areas of prolonged exposure to storm surge wave loading. The managing engineer will initiate PDA of all highway structures along the affected coastline. Embankments are particularly vulnerable to erosion. Inspect all bridges that have storm surge heights that meet or exceed the designated design water level using DDA. States affected should work in conjunction providing resources and personnel to any states in need. II 6–8 ft Storm surge heights should be collected and referenced with highway structures. All areas of coastline affected by storm surge should be evaluated using PDA. III 9–12 ft As the storm surge height increases, the extent of damage is likely going to increase along the coast. This response level will follow the same criteria as Response Level II but with a larger radius. IV (High) > 13 ft In the event of any storm surge heights over 13 ft, SHAs affected should work in conjunction with federal agencies for necessary assistance. Storm surge levels of this magnitude will likely impact large areas of coastline and cause extensive damage that could tax the resources and personnel of the local agencies in charge of structure assessment. It is recommended that detailed FR be performed in order to estimate the geographical extent of damage. Highway structure locations should be monitored with storm surge heights. In any case, when storm surge heights exceed the structure height, following the hurricane, those structures should be evaluated using DDA. Any structure affected by storm surge should be evaluated using PDA. Table 5-7. Storm surge response levels. • Mid-Atlantic and New England Coast: – The total water level at the peak of a hurricane storm is based on the astronomical high tide. – Storm surge duration can vary drastically in this region. • Great Lakes Coast: – Storm surge can be more significant in bays near the ends of lakes. 5.2.6 Flooding Response Levels For purposes of this process manual, response levels will focus on river flooding events. The NWS monitors and records areas of minor, moderate, and major flooding. Maps pro- vided by the NWS can be used by the managing engineer to determine the location and sever- ity of flooding. Once a flooding event occurs, monitoring of all highway structures within the defined flooding boundaries is recommended. Table 5-8 highlights the proposed flooding response levels. Several factors influence flooding consequences; therefore, the following factors should be considered when determining flood response levels (Parola et al. 1998). • Debris can cause aggravated flow conditions which can contribute to scour. • Large debris can accumulate where trees grow only on the immediate stream banks. • Lateral migration of streams and/or stream widening processes may contribute to damage at bridge abutments. 5.2.7 Fire Response Levels Fire events can be categorized as vehicle or local fire (e.g., gasoline fire) or wildfires. Vehicle fires are typically local in nature and will most likely only affect one structure. Wildfires are less likely to cause damage to highway structures because they often occur in the countryside, but the extent of concern is much larger. Table 5-9 details the proposed fire response levels.

54 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual na = not applicable Source: Based on NOAA/NWS (2014g). Response Level River Flooding Extent of Concern Description of Response I Near Flood Stage na The managing engineer will monitor and track scour-critical structures including bridges and culverts. Highway structures elevations should be mapped and cross-referenced with flood maps in order to estimate the likelihood of flooding near or on any highway structure. It is not necessary to perform PDA evaluations at this time. II Minor Flooding (5–10 year recurrence) Contained to rivers Highway structures partially inundated should be assessed and evaluated using PDA. If conditions are suitable, PDA may be performed during flooding scenarios. If flooding conditions are not suitable, PDA should be performed immediately following the flooding event. Scour-critical bridges and culverts should be monitored and evaluated using DDA. In the event of any highway structure scour damage, the appropriate scour reference manuals should be used. III Moderate Flooding (15–40 year recurrence) Rivers and close roads In the event of moderate flooding, the geographical extent may span over several miles. All available SHA personnel and resources should be deployed in order to adequately assess the extent of damage due to flooding. Highway structures that were previously scour critical should be evaluated using DDA. All other highway structures with unknown scour information should be evaluated using PDA. IV (High) Major Flooding (50–100 year recurrence) Determined by severity; likely widespread Major flooding events will likely tax the resources and personnel of the SHA. When there is a lack of personnel and resources, the managing engineer should request federal assistance. All highway structures that were considered scour critical prior to flooding should be evaluated using DDA. All other highway structures should be evaluated using PDA. Table 5-8. Flooding response levels. Response Level Fire Type Extent of Concern Description of Response I Vehicle fire Local The managing engineer will deploy PDARs to proceed to the structure and work with fire officials to determine the severity of the fire. During the fire, the structure should be marked as UNSAFE and appropriate traffic control devices should be in place to detour traffic away from the structure. Once the fire event has subsided, inspection of the structure using DDA should proceed because much of the damage could be internal and difficult to view during a PDA evaluation. II–IV Wildfire Varies In the event of a wildfire, the managing engineer should work with fire agencies monitoring the fire to determine the extent and severity. GIS mapping platforms should be established and cross-referenced with the fire location in order to determine whether the fire will impact any highway structures. If the fire does make contact with any highway structures, the structure is physically and digitally marked as UNSAFE and inspection is delayed until the fire has subsided. The managing engineer works with traffic operations centers to establish alternative routes for the affected structure. It is crucial to establish appropriate traffic control devices to detour the public away from the structure. Because fire damage is variable in nature, DDA procedures should be used instead of PDA. As the size of the fire increases from local to statewide, the managing engineer continues to monitor all structures within the affected range. The number of personnel and inspectors are increased appropriately. Table 5-9. Fire response levels.

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TRB’s National Cooperative Highway Research Program (NCHRP) Research Report 833: Assessing, Coding, and Marking of Highway Structures in Emergency Situations, Volume 2: Assessment Process Manual is intended for managers who will oversee emergency response situations. The report identifies technologies that could be used to assess highway structures in emergency situations. The report addresses technologies that can help with prioritization, coordination, communication, and redundancy.

NCHRP Research Report 833, Volume 1, Volume 2, and Volume 3; along with NCHRP Web-Only Document 223: Guidelines for Development of Smart Apps for Assessing, Coding, and Marking Highway Structures in Emergency Situations provides guidelines for related coding and marking that can be recognized by highway agencies and other organizations that respond to emergencies resulting from natural or man-made disasters.

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