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BRIDGE INSPECTION PRACTICES SUMMARY This synthesis reports bridge inspection practices in the United States and selected foreign countries. The synthesis is a collection of information on formal inspection practices of departments of transportation (DOTs). These are primarily visual inspections and they pro- vide data to bridge registries and databases. For U.S. inspection practices, this synthesis reports on inspection personnel, inspection types, and inspection quality control and quality assurance. Staff titles and functions in inspection programs are reported, together with qual- ifications and training of personnel, formation of inspection teams, and assignment of teams to bridges. Inspection types are described in terms of their scope, methods, and intervals. Quality control and quality assurance programs are reviewed in terms of the procedures employed, staff involved, quality measurements obtained, and the use of quality findings in DOT inspection programs. Foreign practices are presented in the same organization of inspection personnel, types, and quality programs. Comparisons of U.S. and foreign inspection practices are included. Information was obtained from a questionnaire sent to U.S. state transportation depart- ments, similar questionnaires modified individually for transportation agencies in selected foreign countries, and formal documents used by transportation departments and agencies. These documents primarily included bridge inspection manuals, inspection training manuals, and technical memoranda, but also included blank forms for inspections, DOTs' job descrip- tions for inspectors, and descriptions of inspection training courses. Overall, this synthesis in- cludes information from forty U.S. state transportation departments and from roads agencies in eight foreign nations (Denmark, France, Finland, Germany, Norway, South Africa, Sweden, and the United Kingdom). The synthesis also includes, in an appendix, information from a few provin- cial and municipal transport agencies in Canada. Information collected in this synthesis supports findings in two broad areas: inspection practice at U.S. state DOTs in relation to U.S. federal regulations and the scope and kind of bridge inspection programs in foreign counties. U.S. federal regulations, called the National Bridge Inventory Standards (NBIS), establish rules on the structures to inspect, the intervals of inspection, and the qualifications of person- nel. U.S. state DOTs implement the NBIS and also expand on the standards. State programs inspect more structures, perform some inspections more frequently, and place additional requirements on qualifications of personnel. NBIS require periodic inspection of bridges and culverts on public roads having a span greater than 20 ft. Many U.S. states inspect bridges and culverts having shorter spans, and inspect other structures such as sign structures, high-mast lights, retaining walls, and ferry terminals. NBIS set basic intervals for three types of bridge inspection: routine inspection (24 months), fracture-critical member inspection (24 months), and underwater inspection (60 months). Many states set intervals for interim inspections, for in-depth inspections, and for hands-on inspec- tions, as well as for some types of testing and measurements at bridges. Usually states estab-
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2 lish the use and interval for inspections based on structure type, structure condition, roadway class, and traffic volume. Many U.S. state DOTs require that inspection program managers be licensed professional engineers (PEs). NBIS do not require PEs. U.S. state DOTs require PEs to have experience in bridge inspection before acting as inspection team leaders. NBIS does not require experi- ence for PEs who are team leaders. NBIS require that states have procedures for quality assurance and quality control for their inspection programs. Quality programs at state DOTs include reviews of inspection reports, verification of inspections at some bridges, field visits by supervisors to inspection teams at work, periodic on-site reviews of regional and local bridge inspection programs, and contin- uing training of inspection personnel In foreign countries, road agencies in national governments are responsible for bridges and other structures on national roads. Bridges on provincial and local roads are not regulated by national road agencies. Bridge inspection programs in foreign agencies include frequent, sometimes daily, visits to structures by maintenance contractors, annual checks on bridges by maintenance contractors or by national agencies, inspection of known defects at 3-year intervals usually by national agen- cies, and thorough inspection of bridges at 6-year intervals, again usually by national agencies. Inspection programs, overall, combine long-interval inspections by PEs, medium-interval inspections by certified inspectors, and short-interval checks and visits by maintenance contractors. U.S. and foreign practices for bridge inspection differ in the jurisdiction of national trans- port agencies, the use of maintenance contractors within bridge inspection programs, the qualifications of bridge inspectors, and the focus and intervals of bridge inspections. In the United States, federal regulations affect all bridges on public roads. As a result, there is near uniformity in the basic features of inspections programs at U.S. state DOTs. In foreign countries, national transport agencies regulate the national roads only. Transport agencies of provincial and local governments often follow the inspection practices of their national agencies, but this is not required. Foreign countries use contractors to maintain roads and bridges, often as long-term concessions. The maintenance contract undertakes daily visits, annual checks, and, in general, all shot-interval inspections. The transport agency performs longer-interval inspections. In the United States, state DOT personnel perform most inspections at all intervals. Inspection con- sultants are employed, but for inspection services alone, and not as one of the services within a larger maintenance agreement. In foreign countries, qualifications for inspectors range from road foremen to licensed PEs. The higher qualifications are required for the longer-interval inspections. The U.S. NBIS establish a single level of qualification and require this for all inspections. In foreign practice, short-interval inspections are limited intensity or limited scope. That is, frequent visits to bridges are quick checks for new defects or quick checks on the status of known defects. In the United States, underwater inspections and inspection of fracture-critical members are both limited-scope inspections. U.S. state DOTs' use of interim inspections is often directed at known defects. Frequent cursory inspections are not typical of U.S. inspection programs.