Abstract Manager

The rapid replacement of the Highway 400 bridge over Finch Avenue was part of the Finch LRT project, which is an 11 KM public transit facility that is largely at grade.  The existing twin concrete girder bridges were removed and replaced over two weekend full closures using self propelled mobile transporters (SPMT).

The replacement of bridges in the urban freeway network is often extremely disruptive to transportation.  Accelerated bridge construction methods are often used to minimize the disruption but the requirement to use these methods is typically specified by the transport authority rather than the Constructor.  The replacement of the Highway 400 bridge over Finch Avenue is unusual in that the choice to proceed with rapid replacement was made by the builder based on overall project cost and schedule. 

Highway 400 over Finch Avenue is a twin, two span concrete girder bridge with spans of 18m and width for each bridge of 25m.  The project requirements included the full replacement of the superstructure and conversion of the bridge to semi-integral abutment configuration.  The abutments were to be retained and refaced.  Implementing this with staged construction required three stages in each direction with one stage per season.  The rapid replacement approach enabled this work to be completed in one season.  This permitted the extensive follow up work required for the guideway to be completed within the schedule requirements for the project.

The site was challenging for two particular reasons.  The roadway slopes to the east were steep, complicating the transport and placement of the bridge.  The transport of two span continuous concrete girder structures had not been completed previously in Ontario.  Limited available land also required special considerations in the creation of the assembly yards.

The paper focuses on the schedule considerations and the special challenges at this site.