Beginning in 1987, the Federal Highway Administration sponsored a 2-day training course entitled "Inspection of Fracture Critical Bridge Members." The course was developed and taught by Byrd, Tallamy, MacDonald and Lewis Consulting Engineers. It was attended by Federal Highway Administration state and local bridge inspectors who have responsibility for on-site inspection of highway bridges. All state and most local agencies responsible for existing bridges have inspection programs in place. Certain modifications may be necessary in addition to inspector training, if fracture critical members are to be inspected in accordance with the guidelines provided in the course. The guidelines require that each fracture critical member receives a hands-on, close-up 360 deg inspection. Additional nondestructive testing may be appropriate if a potential fracture is identified. Additional resources may be required to provide this level of inspection. The inspector is often not in a position to budget and schedule these resources. Fracture critical members should be first identified by a qualified bridge engineer. It is recommended that each agency include in its program a procedure for documenting and flagging each fracture critical member to ensure that it receives appropriate priority when the bridge is inspected. An inspection plan is formulated for each bridge with fracture critical members that includes equipment, inspection technique, and staffing. The potential for fatigue cracks is evaluated and locations identified. The plan is then discussed with the inspector to ensure that the priorities are understood.
Samenvatting