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Poplar Street Complex
Se i smi c and Redundanc y Ret rof i t Pro j ec t
2001
The Poplar Street Complex is a system of elevated roadways connecting the Poplar Street Bridge to several local, state, and interstate roads converging
in East St. Louis, Illinois. When these elevated structures were built in the late 1960s, no consideration was given to potential seismic demands. The
Illinois Department of Transportation (IDOT) retainedWJE to conduct a comprehensive structural evaluation, and to design retrofit measures to address
seismic deficiencies. A key step in the design was modification of the concrete pier columns so they would be the weak link in the seismic load path.
The department also engagedWJE to evaluate and develop retrofit measures to enhance the redundancy of the bridge superstructure.
WJE’s innovative seismic retrofit approach for the pier columns cost less than half the amount of installing isolation bearings, as recommended
by another consulting firm. IDOT later funded a research study by the University of Illinois to extend the seismic retrofit technology to other
structures. The redundancy retrofit approach for the superstructure was the first of its kind.
Notes of Interest
• The Poplar Street Bridge, officially named the Bernard F.
Dickmann Bridge after a former St. Louis mayor, carries
approximately 120,000 vehicles daily. It is one of the most
heavily used bridges on the Mississippi River.
• Interstate 55, Interstate 64, Interstate 70, and U.S. Highwa
40 cross the Mississippi on the Poplar Street Bridge, and
the official eastern endpoint of Interstate 44 is at the state
line on the bridge.
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