BergerWorld: 2nd Quarter 2008

Constructed in 1940, the original Sikorsky Memorial Bridge carried Connecticut Route 15 over the Housatonic River, linking the cities of Stratford and Milford. In 2000, the Connecticut Department of Transportation (ConnDOT) initiated an ambitious $90 million replacement bridge to accommodate growing traffic demand, and ConnDOT retained Berger, Lehman Associates, P.C. (BLA) to provide construction engineering and inspection services.

BLA supervised the demolition of the existing bridge and the construction of a new, 1,800-foot-long, five-span, continuous steel structure with a composite concrete deck. The substructure included post-tensioned pier caps with concrete footings supported by six-foot diameter drilled shafts embedded in rock sockets. The new structure has six 3.6-meter lanes with three-meter shoulders in each direction, as well as a north side sidewalk. The Route 15 approach was widened to six lanes with median barriers and shoulders adjacent to the left and right travel lanes, and a walkway/bikeway was constructed on the north side of the route.

BLA had to overcome a number of constraints in completing this demanding assignment, including undertaking pier construction and steel erection from barges and constructing a 1,000-foot-long haul road because of limited access to the site due to steep grades and an active railroad track on the east bank of the Housatonic River. Environmental issues were also of prime importance, as swampy grounds on the west bank of the river required the construction of temporary trestles to allow access, and strict monitoring procedures had to be introduced to prevent river pollution. The traffic maintenance was critical to the success of the project, and BLA responded by initiating a multi-staged construction schedule. In addition, work over the active Metro-North Railroad right-of-way had to be coordinated with train schedules, and critical work elements scheduled at off-peak hours to avoid interference with train operations. Other significant considerations included continuous coordination with local, state and federal agencies, such as the Army Corps of Engineers, the Coast Guard, the Environmental Protection Agency and Metro-North, and proper identification and processing of hazardous materials.