| Location:
Washington, D.C.
Expanding Metrorail
services into Virginia, the Washington Metropolitan Area Transit Authority
(WMATA) approved a value engineering proposal to substitute simply supported,
single-cell, external tendon, segmental box girders for three continuous,
twin-cell, cast-in-place box girders. The substitute structures, collectively
referred to as the J-2e structures, included the Cameron Run Bridge (three
spans), the Eisenhower Avenue Bridge (two spans), and the Van Dorn Street
Bridge (two spans).
Approximately
one year after erection, cracking was observed in the diaphragm of all
pier segments. WMATA selected WDP to conduct the revenue operation monitoring
and inspection of the J-2e aerial structures in Fall 1993 and to develop
a maintenance and inspection manual that could be used by WMATA's inspection
forces to monitor performance of the structures.
The inspection
and testing program examined the structural integrity of the aerial structures
through real-time dynamic testing and nondestructive testing. The maintenance
inspection manual produced by WDP provided a comprehensive approach to
inspection of all components of the bridges on a bi-annual basis. A simple
yet rational flow chart was developed that would automatically flag the
need for an engineering review if certain benchmark parameters were exceeded.
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Client:
Transit Authority
Layout
of the segmental bridge spans
Impact-echo
testing from inside box girder
Services
WDP used on this project included:
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