Northeast Anthony Henday Drive (NEAHD) is the last quadrant of Edmonton Ring Road. It was
tendered as a public private partnership (P3) project in 2012. It consists of 39 km highway, 12
interchanges, and 47 bridges, out of which nine bridges were potentially influenced by coal
mines that ceased operation in 1952. History of the existing bridges and geotechnical
investigations demonstrated a high risk of subsidence in this abandoned coal mine area. A
subsidence can cause differential settlement, lateral movement, and twisting to a bridge.
Developing a foundation solution that can accommodate these three dimensional movements,
such that in the event of subsidence, a catastrophic failure is avoided, is the challenge. The
philosophy adopted for the NEAHD Project was to design a bridge to incur reparable levels of
damage should coal mine subsidence occur, without catastrophic failure to the bridge. This
paper presents details how this philosophy was developed, agreed, and implemented for a large
P3 project.
