As the design-builder, Balfour Beatty widened 12.5 miles of SC Route 170 from east of the SC 170/SC 462 intersection to just west of S-761, from two to four lanes and replaced the bridges over the Broad and Chechessee rivers.
The project included the complete design and construction of the roadway and bridges, including bridge structures and roadways, grading, drainage, traffic control, quality control, and signage. Balfour Beatty also performed surveys, obtained right-of-way, purchased properties and relocated utilities.
The existing Broad River swing span bridge, constructed in 1958, was replaced with a new longer and wider bridge (9,000-feet by 80-feet). The existing Chechessee River Bridge, constructed in 1956, was also replaced with a larger bridge (1,920-feet by 80-feet). Balfour Beatty constructed both bridges on an alignment just to the south of the existing structures using temporary trestle bridges spanning the marshes and shallow approaches and barge-mounted equipment supported by a small marine fleet to minimize the environmental impact. The existing bridges remained in operation until the new bridge was opened to traffic. The bridge type selected, a pre-stressed girder system, is a very simple, durable system requiring minimal maintenance. The substructure consisted of piers founded on drilled shafts.
Approximately 12.5 miles of approach roadway to the new bridge was constructed adjacent to the two bridges. Balfour Beatty demolished the existing bridges once traffic was switched over to the new alignment.
Balfour Beatty self-performed all structural work, including the foundations.