FABRICATION ADVANCES KEY TO NEW STEEL TRUSS BRIDGE

The erection of a new steel truss bridge in Charleston, South Carolina is described. Bid competetively with a concrete cable-stayed design, the 1,600-ft through truss span of the Cooper River Bridge employs a parallel-chord Warren truss, with no vertical members or sway bracing. It is noted that because there are no stress-relieving joints in the truss deck, reduced maintenance costs will result. The bridge is 3.1 miles, inlcuding the 800-ft main span, 400-ft flanking truss spans, and long viaducts over tidal marshes and lowlands. The main span will have 155 ft vertical clearance, and 700 ft horizontal clearance over the Cooper River navigation channel. Load factor design was used to obtain the size of all elements of the truss span, while development of high strength steels made possible fabrication of slim, low profile truss elements. Details of the design, truss erection, and the paint system are summarized.