Horner & Shifrin was selected by the Illinois Department of Transportation (IDOT) to design a new ramp connecting I-70 in St. Louis to I-55/64 in Illinois, in order to maintain the connection to Illinois Route 3 and Tudor-Piggott Avenues. Part of a large regional planned improvement to the Poplar Street Bridge, this project also included rehabilitation of the existing ramp structure.

The new structure, a 1,000′ long horizontally curved plate girder bridge, is supported by open column concrete piers and pile support stub abutments. Concrete pier caps were cast in place on the job site due to their size and weight (more than 95 tons each), a method which had seldom been used in Illinois, reducing the construction time of the caps by six weeks each. Located in a high seismic zone, the design of the bridge was required to resist seismic forces.

The existing structure was widened to accommodate the addition of the ramp. This 1,300′ long horizontally curved and tapered plate girder bridge now carries four lanes of interstate traffic across its entire length. Due to its location, the structure was slated for major seismic retrofits, which entailed seat widening, post-tension footings, and the use of fiber wraps on the columns. Two of the piers were removed and replaced while the bridge was under traffic.

Project Scope

Project Components