BRIDGE CONSTRUCTION: GRS-IBS construction method applied to two Wisconsin bridges

Aug. 26, 2016

WisDOT is using new technology on the Dodge County bridges

The Wisconsin Department of Transportation (WisDOT) unveiled replacement work at two Dodge County bridges on Thursday to showcase a new bridge construction technique, which simplifies the process and reduces project time while potentially increasing quality.

The bridges spanning Shaw Brook and Pratt Creek on county highways S and KW, respectively, date back nearly to World War II and were falling into disrepair. WisDOT worked with local officials to secure a Federal Highway Administration grant to replace the structures using a concept known as Geosynthetic Reinforced Soil – Integrated Bridge System (GRS-IBS).

The GRS-IBS construction method was developed by the Federal Highway Administration using basic earthwork techniques to create a reinforced soil foundation for the abutment and an integrated approach. It is a similar method to retaining wall constructions, and is considered an ideal solution for smaller, single-span bridges over low-velocity waterways.

Benefits include accelerated construction, reduced cost and flexible design. In terms of maintenance, the simplicity of the structure is expected to reduce the number of problems that can occur among the individual parts of more complex bridge systems.

Work on both bridges began in early July and is expected to finish in September. Average daily traffic on each bridge ranges between 500 and 700 vehicles each day. An expected reduction in construction time, compared to conventional methods, results in a welcome reduction in detours and delays.