Bridge Inspection Practices (2007)

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Bridge inspections are performed for at least three reasons: (1) to ensure the safety of bridges, (2) to discover needs in maintenance and repair, and (3) to prepare for bridge reha- bilitation. These three reasons produce three levels of in- spection: (1) short-interval checks of safety, (2) medium- interval reviews of maintenance needs, and (3) long-interval assessments of needs for major work. U.S. federal regulations provide at least two levels of in- spections; interim inspections that are short-interval and detail- specific, and routine inspections that are medium-interval and full-extent. Routine inspection at 48-month intervals is applied to a few robust bridges in good condition. The poli- cies of U.S. state departments of transportation (DOTs) often provide three levels of inspection: (1) short-interval interim inspections; (2) medium-interval routine inspections; and (3) longer-interval, in-depth, close-access, or increased-intensity inspections for at least some bridges or details. In foreign practice, frequent, less-detailed inspections are used together with a long-interval Principal or Major inspec- tions. Of the countries studied, three employ short-, medium-, and long-interval periodic inspections for bridges, and nearly all identified noninterval special or project-level inspections for repair projects (Table 77). Inspection types in U.S. and in foreign practices can be compared in terms of inspector qualifications, inspection intensity, repair recommendations, and inspection program control. Table 78 cites the qualifications of inspectors required for each type of inspection. In foreign practice, inspections at 12-month or shorter intervals are done by maintenance fore- men or other capable, noncertified personnel. Inspections at medium intervals require certified bridge inspectors. Long- interval inspections demand degreed engineers who are also certified bridge inspectors. U.S. federal regulations establish a single personnel level, a team leader, and require this level for all inspections. U.S. team leaders need not be engineers. Inspection intensity varies with inspection interval (Table 79). In foreign practice, short-interval inspections 48 might be as cursory as drive-by inspections. Medium-interval inspections often require that inspectors be able to view all bridge components, whereas long-interval inspections re- quire hands-on access. U.S. federal regulations require hands-on inspection of fracture-critical members, but oth- erwise allow inspectors to determine which bridges or por- tions of bridges need hands-on inspection. Some U.S. state DOTs have policies that require hands-on inspection at spe- cific details, for specific conditions, or within specific max- imum intervals. In foreign practice, depending on interval, inspections may collect few condition ratings, all condition ratings or all condition ratings plus field measurements, results of materi- als tests, or other quantitative data (Table 80). U.S. federal regulations require updates to National Bridge Inventory (NBI) data at each routine inspection. For most U.S. bridges, this entails a complete set of NBI condition ratings plus any changes to appraisal ratings and inventory data at 24-month intervals. In foreign practice, recommendations for work at bridges range from superficial maintenance needs noted for the most frequent inspections, to complete identification of repair needs during inspections at medium intervals, to de- tailed recommendations of actions, quantities, and costs at long intervals (Table 81). In U.S. practice, maintenance recommendations are updated every 24 months for most bridges. In foreign practice, authority for inspections is usually shared between two branches of a road agency, or between a road agency and its maintenance contractors. The most fre- quent inspections are done by maintenance crews and reported to agencies’ bridge inspection programs (Table 82). Inspections that require certified inspectors and occur at longer intervals are directly administered by agencies’ in- spection programs. U.S. federal regulations require team leaders for all inspections, with the result that administration of all inspection work remains within a DOT’s inspection program using either DOT staff or inspection consultants. CHAPTER SIX CONCLUSIONS

49 Inspection Interval U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom 3 months Superficial Superficial 1 year Routine Annual Annual General Monitoring Superficial 2 year Routine General 3 year IQOA Minor General 4 year Routine 48-month 5 year General 5-year Major Principal 6 year Principal Detailed Major Major Principal 7 year 8 year General 8-year 10 year In-depth 120-month For Project Special Economic Special Special Special Special Project-level Special Special IQOA = Image de la Qualité des Ouvrages díArt. Personnel U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom Non-Certified Inspector Routine Annual Annual Superficial General Monitoring Superficial Superficial Routine General 5-year IQOA Minor General Routine 48-month General Detailed 8-year Agency Certified Inspector In-depth 120-month Principal Basic Major Major Principal General PrincipalEngineer Economic Special Special IQOA = Image de la Qualité des Ouvrages d’Art. TABLE 77 BRIDGE INSPECTIONS TABLE 78 INSPECTORS AND INSPECTIONS Inspection Access U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom Drive-By Daily Routine Routine Routine Routine Annual Superficial SuperficialVisible Routine 48-month Principal IQOA Minor General Monitoring General General Arms Length In-depth 120-month General Detailed 5-year* Major Major Principal Major Principal* *Said to be “arms-length,” but traffic lane closures are rarely provided. IQOA = Image de la Qualité des Ouvrages d’Art. TABLE 79 INSPECTIONS AND INTENSITY Condition Data U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom None or Few Routine Annual Minor General Monitoring Superficial Superficial IQOA General GeneralAll Condition Ratings Routine Principal General 5-year Detailed Major Principal Major Principal Tests and Measurements Special General 8-year Special Major Project- level Special Special IQOA = Image de la Qualité des Ouvrages d’Art. TABLE 80 INSPECTIONS AND CONDITION DATA

50 Actions U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom Annual Superficial SuperficialCleaning Routine Annual IQOA Minor General Monitoring General General General 5-year All Actions Routine Principal General 8-year Detailed Major Major Principal Major Principal Costs and Quantities Special Economic Special Special Special Special Project- level Special IQOA = Image de la Qualité des Ouvrages d’Art. Inspection Program U.S. Denmark Finland France Germany Norway South Africa Sweden United Kingdom Daily Annual Routine Superficial Monitoring Superficial SuperficialPartial or No Control Routine Annual Routine Principal General IQOA 5-year Minor General General General Routine 48-month General 8-year Major Principal Major Principal Primary Control In-depth 120-month Economic Special Special Detailed Major Special Project- level Special Special IQOA = Image de la Qualité des Ouvrages d’Art. TABLE 81 INSPECTIONS AND MAINTENANCE AND REPAIR RECOMMENDATIONS TABLE 82 INSPECTIONS AND SUPERVISION BY INSPECTION PROGRAM