White Paper on Bridge Inspection and Rating

Abstract

A joint ad-hoc group of American Society of Engineers/Structures EngineeringInstitute and American Association of State Highway and TransportationOfficials (ASCE/SEI–AASHTO) was formed to address issues dealingwith methods and practices used to ensure the safety of highway bridgesacross the United States. The group concluded that, in general, thecurrent National Bridge Inspection Standards (NBIS) and programsdeveloped to address those standards have adequate policies and proceduresin place to ensure public safety. The group also concluded that thecurrent system can be improved; and identified gaps and needs toimprove bridge safety and ensure uniformity, consistency, and reliabilityof bridge inspections nationwide. As developed by the adhoc group,this white paper describes gaps, needs, and issues associated withthe current practices and policies for the condition assessment ofbridges. These have been divided into ten general categories fromwhich the following concepts are highlighted: • A more rational,risk-based approach to determining the appropriate inspection intervalsfor bridges is needed, as opposed to a set twenty-four month cyclefor all bridges. This approach would consider factors such as thedesign, details, materials, age, and loading of specific bridgesto determine the interval between inspections.• New and more assertive types of Quality Control/Quality Assurance(QA), such as performance testing of inspectors, could be used toencourage consistency of inspection practices.• The consistency and effectiveness of inspections nationally couldbe improved if inspector qualifications were matched to the bridgetype, condition, and complexity in a more uniform manner.• A bridge inspection manual for nationwide use should be developedwith expanded use of photographs, illustrations, and detailed drawingsindicating specific deterioration conditions and methods of reportingdeterioration.• There is a need to have close collaboration between those responsiblefor maintenance and repair of a bridge and those responsible forbridge inspection.• The load ratings process should be reliable, uniform, and consistentacross the states.• The development and maintenance of a centralized system for documentingcritical deterioration in bridges, as experienced by bridge owners,is needed to support the interchange of information and provide aresource for bridge owners.• There is a need to develop standardized procedures for special inspectionsinvolving nondestructive evaluation NDE, for example pin inspections,to provide more guidance to bridge owners.• Terms such as structurally deficient, functionally obsolete, andfracture critical require accurate definitions in the public arenasuch that public perception of bridge safety is consistent with thefacts.• A mechanism should be developed to ensure the critical conditionsidentified during bridge inspection are addressed in a timely manner.