Gordie Howe International Bridge Construction Anxieties

Gordie Howe International Bridge Construction Anxieties—The Bridge

Pickle, R. / van Rooyen, A.

The Gordie Howe International Bridge project consists of four components—the Canadian Port of Entry, the Bridge itself, the US Port of Entry and the Michigan Interchange on I-75. The Project is being delivered through a Public–Private Partnership Agreement (P3). The design phase of the project commenced in July, 2018, with site preparation works by the private-sector partner beginning on both sides of the river in January, 2019. The essence of the project is the six-lane cable stayed bridge, providing three Canada-bound lanes and three US-bound lanes over the Detroit River, between Windsor, Ontario and Detroit, Michigan. The bridge will have a clear span of at least 853 m (2798 ft) across the Detroit River with no piers in the water. Two approach bridges, one on each side, will connect the main span to the Canadian Port of Entry and the US Port of Entry. The crossing, including the bridge and approaches, will be approximately 2.5 km in length. This cable stayed bridge will be the 6th longest in the world, the longest in North America and will be the longest composite cable stayed bridge in the world, with out-of-the-river drilled shaft foundations and concrete towers, at 218 m in height. These towers will be the tallest structures in both the Windsor and Detroit skylines. The approach bridges will be all concrete design, 11 spans on US side, 10 spans on the Canadian side, with precast concrete girders and drilled shaft/driven pile foundations. The six drilled shafts for each of the 4 Tower foundations are reinforced concrete in 3.162 m OD steel casings set 4.5 m into competent rock. The six anchor and side span pier foundations are 3.162 m diameter reinforced concrete in a steel casing on the Canadian side and 3.0 m diameter on the US side, set 4.8 m, minimum, into the bedrock. Bedrock is approximately 30 m below ground surface and the overburden is silty sands and silty clays deposited during glacial recession across the lands. The installation of the drilled shafts for the Tower foundations and the side span and anchor shafts began at various times between July, 2019 and February 2020. Two of the last shafts for the Canadian spans, to be drilled and poured, a side span shaft and an anchor shaft, became problematic. Shaft casing deflection and distortion, casing wounds, groundwater leakage and concrete anomalies necessitated significant remedial works including alterations to the rock sockets, modifications to the reinforcing steel, concrete removal and micro-piling. The subsequent construction of the respective pier footings was able to commence in December, 2020.