DESCRIPTION

GSA required an access road to its newly expanded facility for the FDA. A bridge approximately 500 ft long was designed which included three precast arch spans and MSE wingwalls to cross over the Paint Branch Creek.

CHALLENGES

There were multiple challenges on this project which included a tight 18 month schedule, up to 18 ft of soft unsuitable soils underlying the proposed MSE wingwalls as well as environmental considerations concerning the Paint Branch Creek. The first recommendation was for the unsuitable soft soils to be undercut and replaced with AASHTO 57 or CR-6 material. This recommendation proved to be both costly and time consuming.

SOLUTION

GeoStructures developed a design alternative using the Impact® System to improve the unsuitable fill soils beneath the MSE walls. By combining the Impact System stability design with the design of the MSE wall system, they were able to optimize the designs for both elements. GeoStructures installed the Impact® elements, MSE Wall and Arches for the project. Through design optimization and having one subcontractor responsible for installing Impact elements, the MSE Wall and the Arch, this saved the project both time and money.