Physical modelling of foundations for Confederation Bridge, Canada

The 12.8 km long Confederation Bridge between Prince Edward Island and mainland New Brunswick is the longest continuous marine span bridge in Canada. The bridge is supported on precast concrete piers founded on bedrock using ring shaped footings. Geotechnical design of the pier foundations was complicated by extremely complex foundation conditions and severe environmental loads due to ice, wind, current and waves. Reduced-scale physical model tests were carried out to investigate potential failure mechanisms and behaviour due to different loading and foundation conditions. Artificial rock was used to simulate the geotechnical design properties of the foundation rock and models were subjected to loads representative of those considered for the actual pier. This experimental program has led to a more fundamental understanding of the geotechnical aspects of foundation design and an improved design methodology. Substantial construction savings were realised due to reductions in dredging depths and smaller foundation dimensions.