Wyoming Department of Transportation
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Bridge Inspection Program

Bridge Inspection Program


Bridge Inspection Overview

  • The Wyoming Department of Transportation owns and maintains 1938 structures. Each of these, as well as the 847 bridges owned and maintained by the towns, cities, counties, and other state agencies, are carefully inspected at least once every two years by teams of highly trained WYDOT bridge inspectors.

    These hands-on inspections are completed in accordance with the requirements set forth in the National Bridge Inspection Standards outlined in the Code of Federal Regulations Title 23, Part 650, Subpart C. The inspection procedures are based on the codes, instructions, assessment criteria, and reporting requirements of the Federal Highway Administration’s Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges, the PONTIS and Wyoming Element level bridge inspection criteria, and the AASHTO Manual for Bridge Evaluation. 

    There are exceptions to the two-year frequency. Bridges requiring posted load restrictions are inspected annually. Additionally, bridges having certain levels or types of deterioration or with specific details that may affect the safe usage of the structure receive special inspections designed to closely monitor their unique condition.
     
    Bridges require periodic maintenance to remain safe and serviceable, and our inspections help to identify those elements needing repair or replacement. When a condition is found that may affect the ability of the structure to carry the anticipated loads, a rating is completed and traffic crossing the structure may be limited until the condition can be corrected or the bridge is replaced.
     
    The inspection results are submitted to the Federal Highway Administration annually. 

    Our WYDOT bridge inspection teams are working hard to ensure your safety on Wyoming’s bridges.

Definitions

  • • Bridge - A structure erected over a depression or an obstruction, such as a waterway, highway or railway, having a passageway for carrying traffic and an opening, measured along the center of the roadway, of more than 20 feet. This may include multiple pipe culvert installations where the clear distance between openings is less than half of the smaller opening.
     
    • Sufficiency Rating - A numerical rating of a bridge ranging from 0 - 100 of which 55 percent is based on the structural adequacy and safety, 30 percent on serviceability and functional obsolescence, and 15 percent on essentiality for public use. The sufficiency rating is used as a basis for establishing eligibility and priority for replacement or rehabilitation of bridges, and not as a direct measure of the structural adequacy or safeness of a bridge.
     
    • Structurally Deficient - A bridge classification which is based on an assessment of physical condition and load ratings of a bridge. This indicates that there are elements of the bridge that have experienced a level of deterioration that could reduce the structure’s ability to carry the anticipated traffic loads. The fact that a bridge is structurally deficient does not imply that it is likely to collapse or that it is unsafe. Rather, maintenance and rehabilitation of various components are necessary to restore its condition.
     
    • Functionally Obsolete - A bridge classification which indicates that the structure may not have the lane widths, shoulder widths, vertical and horizontal clearances to adequately service the current and future traffic volumes and types. A functionally obsolete bridge may not provide a desired level of hydraulic capacity.
     
    • Selection List - A list published by the FHWA which contains those structures that have a sufficiency rating of 80 or less and are either structurally deficient or functionally obsolete and have not been rehabilitated within 10 years. Bridges that appear on the FHWA's selection list are eligible for federal bridge replacement and rehabilitation funding.
     
    • Deficient Bridge - A structure that appears on the FHWA’s Selection List.
     
    • Load Rating - A numerical analysis which is based on the structural configuration and condition of the bridge that estimates the weight of a vehicle that can safely cross the structure without causing damage to it.
     
            • Inventory Rating - The weight of a given vehicle that can safely cross the structure on a routine or daily basis.
            • Operating Rating - The maximum weight of a given vehicle that can safely cross the bridge on an occasional basis.
     
    • Restricted Bridge - A structure having limitations on the maximum weight of vehicles allowed to cross the bridge.
     
    • Fracture Critical - A steel member whose failure would probably cause a portion of or the entire bridge to collapse.
     
    • Critical Finding - A structural or safety-related condition that requires immediate action to allow the bridge to safely maintain an acceptable level of service. Critical findings are tied to a structural condition or deficiency affecting the load carrying capacity of the bridge.
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