摘要: |
Bridge deterioration is a significant problem facing highway agencies nationwide. In order for these agencies to make sound decisions regarding their bridge maintenance and rehabilitation efforts, they require comprehensive and detailed information on bridge conditions. In 1997, the Arizona Department of Transportation selected Burgess & Niple (B&N) to perform in-depth inspections of 172 steel bridges throughout the state. Bridges were up to 1,800 ft (549 m) long and 700 ft (213 m) high and located in mainly rural areas of the state. The primary objective was to perform a close (hands-on) visual inspection of each steel bridge in order to detect and document any deficiencies of the bridge components. Difficulty of access was not allowed to interfere with performing a thorough inspection. Visual observations were to be supplemented with non-destructive testing when necessary to define the limits of deterioration or document the condition of items such as bridge pins. Special emphasis was placed on fatigue prone details and fracture critical members. A separate report on inspection findings was issued for each bridge. This report included such information as deficiencies found, National Bridge Inspection Standards (NBIS) condition ratings, PONTIS element data, channel profile/vertical clearance diagrams, repair/maintenance recommendations, suggested inspection frequency and the inspection cost. This paper describes the procedures taken by B&N in preparing for and performing the inspections as well as the results. |