2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference


Title
Superstructure Replacement and Substructure Modifications to the Fort Nelson River Bridge in Northern BC


Author(s)
Mr. Ken Rebel, McElhanney - Victoria (Presenter)
Mr. Raj Singh, McElhanney Consulting Services Ltd.
Abstract

The existing 8-span 430 m long single-lane Fort Nelson River Bridge on Hwy 77 was constructed in 1983 and is one of world’s longest ACROW bridges. The British Columbia Ministry of Transportation owns the bridge and because of increasing traffic demands in the region would like to replace the narrow single lane superstructure with a new two lane superstructure utilizing the existing piers and abutments.

McElhanney Consulting Services Limited has undertaken the initial foundation evaluation, condition inspection, conceptual and detailed design of the new superstructure and rehabilitation of existing abutments and piers to accommodate the heavier and wider superstructure.  The existing bridge has spans of 34m – 37m – 58m – 70m – 70m – 70m – 58m – 32m with the longer spans using a double height ACROW section and the shorter spans using a single height section.  The new superstructure consists of a full depth precast concrete composite deck with an out to out width of 10.0 metres and three continuous lines of steel girders that vary in depth from 1.1 metres to 3.3 metres. The girders have been designed to be launched into place from the north end of the bridge. The abutments require additional piles and modified seats and backwalls to accommodate the wider structure.  The land piers also require new steel pipe piles cast into new wider pile caps that support the existing pier shafts. As the bridge is to be constructed in the extreme north, a significant amount of the structure is to be fabricated off-site and assembled on site.