Cheticamp River Bridge Construction Phasing/Temporary Detour Structure, Cheticam

 

The initial planning stage for the replacement of the Cheticamp River Bridge involved the evaluation and assessment of several design options. It was 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. In addition to providing an aesthetically pleasing structure, this design option allowed for the implementation of a phased construction method in which 40\% of the existing bridge was demolished and the remaining 60\% was kept open to traffic as a one way alternating detour while construction of the new bridge progressed. After the new bridge was completed, traffic was seamlessly transferred to the new structure and the existing bridge was removed, complete with the existing piers and remaining portions of the abutments located under the new structure. This method of construction allowed the new bridge to be built partially within the footprint of the existing structure, eliminated impacts on private lands, minimized environmental footprint, removed the requirement for a detour structure and provided the most efficient construction schedule.

While this design eliminated the need for a detour bridge, thereby reducing the cost of the project significantly, it also greatly increased the complexity of the design of this structure. It required advanced bridge design and construction experience, along with sophisticated 3-D finite element modeling, to ensure the bridge had the required strength and stability for not only the 75 year service life, but also during all phases of construction. The resulting sophisticated analysis produced the most cost-effective and environmentally friendly bridge replacement strategy and allowed for the most efficient use of materials, including steel, to produce the new bridge structure.

Client: Public Works and Government Services Canada

Value: $7.5 M

Year: 2010

Role: Preliminary and Detailed Bridge Designers