Schnabel is the geotechnical engineer of record for 14 miles of the Intercounty Connector (ICC): a new controlled access, six-lane toll roadway. This highway connects I-270 and I-95 on the Maryland side of the Washington, D.C. metropolitan area. We were part of the team for two separate design-build contracts, A and B, let by the Maryland Department of Transportation State Highway Administration.
Contract A is a 7.2-mile section of ICC that includes three interchanges, five miles of noise walls, and 23 bridges. Construction of this $479 million project began in 2007 and was completed in 2010. Contract B is another seven-mile section of the new highway. It includes two interchanges, 10 bridges, noise walls, erosion and sediment control, and multiple drainage facilities. The cost of this portion of the ICC was $560 million and it was completed in 2011.
One of the critical challenges of the project was wet, high-plastic soils, which could not be reused as is and would be costly to haul off site. We solved this problem for the design-build team by developing earthwork specifications and soil remediation designs allowing most of the on-site soils to be reused. Our drilled shaft foundation design for the mainline bridges eliminated the need for multiple drilled shafts at each pier column, resulting in substantial cost savings and a shorter schedule.