Lavis Construction Co. Ltd. received a $1,100,000 contract from the Ministry of Transportation of Ontario for the rehabilitation of the Highway 21 bridge at Bayfield. The project included a complete replacement of the gabion retaining structures in the river with steel sheet piling. To facilitate removal of the gabions and to enhance the slope stability of the existing bank, which is at a slope of 1.6 to 1, we proposed a temporary berm be constructed in the river and expedited regulatory approval. This enabled the contractor to significantly reduce the amount of work that had to be carried out from floating plant.

Philip Lampkin was the quality verification engineer for the installation of the soil anchors. This involved proof testing of the one tie rod to specified loads and measuring deflection over a period of time. We analysed the results to provide a determination of the working load capacity of the tie rods. The test results established the acceptablity of the anchor
construction and strength. The remaining production anchors were subsequently tested to specified acceptance criteria.

The contract also required that the wales of the new wall be curved to follow the 10 metre radius of the proposed alignment. The wales could not be bent, however, because they were specified to be inclined to the wall to accommodate the specified slope on the soil anchors. This was a mistake in the contract and Riggs Engineering was asked to provide a solution. We undertook a finite element analysis of the structure and determined the
complete stress distribution along the wales. We proposed that the wale channels be cut in 1.22 metre sections to match the profile of the steel sheet piles. We designed a combination of partial penetration groove welds, flange plates and web plates to fully transfer the shear, axial and bending stresses in the connections. We provided detailed
shop drawings and design calculations for approval by MTO. The work was successfully implemented by the contractor.