Poplar Street Bridge Interchange Reconstruction


St. Louis, Missouri


Innovation meets challenges, maintains traffic flow, improves safety 


•    Design improvements improve capacity and safety in restrictive urban space
•    Innovative methods minimize traffic disruption
•    Project is delivered under budget

HNTB was selected by the Missouri Department of Transportation to design new directional ramps to replace functionally and structurally obsolete existing structures.  

Project goals were to improve the geometrics, capacity and safety of the new ramps, minimize traffic disruption during construction and deliver plans in 10 months that result in construction bids under the DOT’s budget. 

The team evaluated several alternatives, including accelerated bridge construction of the ramp with the heaviest traffic movement. Traffic flowed smoothly through construction due to a staging plan and contract incentives that limited the closure of the ramp to less than 30 days.

The first phase, which includes the westbound ramps, was completed under the original construction budget. Budget savings was realized by applying expertise in practical design of the ramp geometry along with applying a conditional mean spectrum approach for seismic bridge design.