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55 C H A P T E R 6 6.1 Marking System A coding and marking system was developed to support uniform communication between PDARs, inspectors, maintenance crews, engineers, and others as necessary. The terms INSPECTED, LIMITED USE, and UNSAFE were chosen to be consistent with the process used for buildings (i.e., ATC-20). The term INSPECTED was selected because many bridges in use today are classified as âstructurally deficient.â Given that PDAs should take no more than 30 minutes per structure, the assessment is likely not detailed enough to imply any structural capacity other than that the structure appears to be in the same condition as it was prior to the emergency event. To maintain consistency within the whole process, the terms were also used for DDA and EI. All inspected structures within the impacted region should be marked both physically (in the PDA stage) and digitally (in the FR and PDA stages) after an assessment is conducted and the cod- ing for the structures is established. Structures shall be marked physically in an obvious location on both ends of major elements of the structure using placards affixed with a color decal of the coding option (see Figure 6-1 for the placard and Figure 6-2 for the coding options). For example, the placard with the decal would be on the right-hand side of the approach to the bridge (i.e., on railings or fixed structural elements at both bridge abutments). These posting placards and decals should be available at all offices and in the inspection vehicles. Structures shall be marked digitally in a central database and/or GIS map that is accessible to authorized staff with a secure connection. The use of QR codes on the placard in concert with smart devices (i.e., smartphones or tablets) or stand-alone readers can significantly reduce coding time and improve information flow and reliability between personnel and across agen- cies. PDARs should have a decal/sticker with a QR code or have access to a mobile QR code printing machine. The marking (and hence contents of the QR codes) must clearly indicate the agency that made the marking, the assessment stage (i.e., PDA or DDA), the date and time of the assess- ment, the resultant coding (i.e., INSPECTED, LIMITED USE, UNSAFE), actions taken (e.g., close structure, close lane), and name/initials of the PDAR. After undergoing PDA, highway structures should be posted with one of two placards: INSPECTED or UNSAFE (refer to Figure 5-1). If a structure is marked UNSAFE during a PDA evaluation, it will be further evaluated using DDA. During DDA, highway structures are marked with one of three decals on a new/updated placard: INSPECTED, LIMITED USE, or UNSAFE (refer to Figure 5-1). This posting lets the SHAs, PDARs, inspectors, and the public know the condition of the structure as well as the date and time the assessment was performed. The system used for marking a highway structure and the definition of each posting category are summarized in Table 6-1. Coding and Marking Guidelines
56 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual Figure 6-1. Example marking placard. Figure 6-2. Marking codes for PDA (left) and DDA (right). These can be printed as decals to be placed on the placard shown in Figure 6-1.
Coding and Marking Guidelines 57 In addition to posting a highway structure, it may be necessary to designate restricted use of certain parts of the structure. These can be hazardous areas on or around the highway structure. For example, if a bridge deck is badly cracked or raised on one side, traffic should be redirected onto the non-damaged portion of the bridge. There may be a need to change the coding and marking of a highway structure. This can result from several possible situations including the following: ⢠A DDA following an initial PDA ⢠An EI ⢠Reinspection to verify or correct an existing posting ⢠Reinspection after another emergency event ⢠Reinspection after temporary repairs have been made ⢠Reinspection after removal of finishes to expose concealed conditions Any change in posting category must be done by an authorized representative of the agency in charge of that particular highway structure. 6.2 Element Damage Levels Prior to coding and marking the overall structure, the PDARs should quickly assess the state of individual elements. This is useful information for load rating analyses at the DDA stage as well as for tracking the amount of damage for loss estimates. This section provides definitions for the individual element ratings for each highway structure. It should be noted that these damage levels are separate from the final decision for overall coding and marking of the structure as either INSPECTED or UNSAFE. These damage levels are specific to basic structure elements and are used to provide information for repair, prioritization, and subsequent assessment procedures. These damage levels are marked in the assessment forms. For each highway structure, a list of common elements is provided in Volume 3: Coding and Marking Guidelines. These elements should be reviewed independently and coded using Table 6-2. Each highway structure has different elements corresponding with damage level to be used for reference. When the condition of an element is not clear, it should be coded conservatively. Upon coding the individual elements, an overall marking will be decided for the structure. When elements are coded as minor or moderate, the overall marking is less clear. A conservative judgment should be used when making the final marking decision. If a structural element (e.g., bridge columns, bearings, or wingwall; tunnel deck; overhead sign column support) receives a Marking Classification Description INSPECTED (Green) This classification utilizes a green color code and indicates that, subject to the inspection at the current stage, no apparent damage was found and the pre-event load-carrying capabilities of the structure appear to be fully intact. No restrictions on use. LIMITED USE (Yellow) This classification utilizes a yellow color code and indicates that dangerous conditions are believed to be present. Usage is restricted to ensure public safety. The restrictions to use must be clearly defined by symbols and can include lane closures, vehicle load limits, or use by emergency vehicles only. UNSAFE (Red) This classification utilizes a red color code and indicates that extreme hazards are present, the structure is in imminent danger of collapse, or the structure has collapsed. The structure is closed to all traffic. Table 6-1. Highway structure coding and marking classifications for PDA and DDA.
58 Assessing, Coding, and Marking of Highway Structures in Emergency Situations: Assessment Process Manual moderate damage-level rating, the structure should be marked as UNSAFE. If a non-structural element (e.g., bridge parapet, tunnel railing, and overhead sign catwalk) receives a moderate damage-level rating, the structure may be marked as INSPECTED, if there is no other structural damage, although precautions and cordoning off the affected areas should be made to ensure safety and to make sure users are aware that there is a safety hazard. 6.3 Assessment Form Integration PDA forms provide information on the structural integrity of a highway structure following an emergency event. The information contained in these forms is especially useful for sub- sequent inspections such as DDA and EI. The âDamage Summaryâ section on the form is use- ful for providing an economic and monetary estimate on the damage to a structure. Although an estimate, this percentage can help managing engineers prioritize and plan for subsequent inspections and retrofits. âFeature Descriptionâ ratings provide valuable information for DDA and EI evaluations. For example, if a structure is determined to have moderate damage for one element and no damage for the remaining elements, DDA and EI inspectors do not need to provide a detailed evaluation of the remaining elements. This is particularly useful for determining appropriate inspection technologies as managing engineers can better adjust the equipment needed. Damage Level Description None (Green) The element and/or structure shows little to no signs of damage. Minor (Yellow) The element shows signs of cosmetic or non-structural damage that has little to no effect on the system integrity. Structure appears capable to carry traffic. Moderate (Orange) The element has experienced structural or geotechnical damage that may affect the system integrity. Severe (Red) The element is damaged where it cannot function properly. Structure may be in danger of collapse. If any element is marked as severe, the structure should be posted UNSAFE. Table 6-2. Element damage-level descriptions.
