Silver Hope Overpass

Hope, BC, Canada

Background

The Silver Hope Overpass spans the Trans-Canada Highway near Hope, BC, and is a five span braced steel girder bridge with an epoxy-coated, rebar reinforced, concrete bridge deck. Shortly after the bridge was constructed, cracks began to develop throughout the center of the deck slab at approximately one to two meters (3.3 to 6.6 feet) thick. Initially extensive water leakage occurred through these cracks during periods of rain, leaving white leachate deposits that highlighted the cracks location on the deck slab soffit.

Solution

As shown, the deck initially cracked extensively, which was believed to be caused by reduced bond associated with epoxy-coated, reinforcing steel and partially to the predominantly round coarse aggregate used in the deck concrete. Within one year of the Krystol™ application, the underside of the deck was observed to be free of leakage. Over a period of nine years both Ministry of Transportation personnel and HBT Agra Engineering personnel continued to perform inspections on the bridge and no subsequent leakage occurred. In 1994 core samples were taken from the bridge deck. The samples were petrographically examined and determined to be in excellent condition with no evidence of corrosion. The bridge and its waterproofing system continue to perform as specified.