CREATING A GATEWAY TO THE CAPE BRETON HIGHLANDS THROUGH INNOVATIVE DESIGN AND CONSTRUCTION METHODS

摘要

The Cheticamp River Bridge serves as a gateway to the Cape Breton Highlands National Park. In 2008 PWGSC opted to replace the deteriorating existing structure. Preliminary design determined that a long simple span twin trapezoidal steel box girder bridge, complete with a composite precast concrete deck system best satisfied the project objectives. The replacement bridge is an 81.5m single span structure on a 34 degree skew with semi-integral abutments founded on steel pipe piles. Harbourside Engineering Consultants created an innovative phased construction method in which 40% of the existing bridge was demolished and the remaining 60% was used as a single alternating lane detour throughout construction. Girders were designed to span over the existing piers and partially demolished existing abutments. The girders were assembled on the west approach and driven across the remaining existing bridge, where two cranes then lifted each girder onto the new foundations. This method allowed for efficient erection of the girders, created a small footprint of construction, eliminated impacts on private lands, minimized the environmental footprint and required no detour structure. After the new bridge was completed, traffic was transferred to the new structure and the existing bridge superstructure and substructures were removed.