Item - 2025.IE21.8

The Infrastructure and Environment Committee recommends that:  

1. City Council endorse the replacement of the existing single-lane Bailey bridge on Unwin Avenue with the Alternative 2 bridge replacement option, as described in the report (April 23, 2025) from the General Manager, Transportation Services, to inform advancement of detailed design and construction of the recommended bridge replacement option.

Transportation Services, in partnership with Engineering and Construction Services, has completed a Replacement Study for the Unwin Avenue Bailey Bridge. The purpose of the study was to evaluate a range of conceptual design alternatives for the replacement of the existing temporary, single-lane modular bridge spanning over the R.L. Hearn circulation channel and provide a recommendation on the preferred bridge replacement option, to be carried forward to detailed design.

The existing Unwin Avenue bridge was constructed in 2008 and is now 17 years old. In 2024, the closure of the Ship Channel bridge for emergency repairs restricted access to the lands south of the Ship Channel and placed significant pressure on the existing single-lane Bailey bridge on Unwin Avenue. In keeping with the need to modernize Port Lands infrastructure to better accommodate both existing and future traffic demands, this study will provide near-term improvements in advance of a future realignment of Unwin Avenue, as established in the 2017 Council-endorsed Port Lands and South of Eastern Transportation and Servicing Master Plan.

The study was conducted using a decision-making matrix to rank the performance of three conceptual bridge alternatives based on several key factors and both qualitative and quantitative scoring criteria. The evaluation was further supported by a structural and civil capital cost estimate to assess the short-term capital needs of each alternative.

Based on the point-based evaluation and ranking, Alternative 2, the complete replacement of the existing bridge with a two-lane, heavy-duty modular bridge was identified as the preferred replacement option. This alternative offered the best balance between constructability, technical performance, durability, and cost. Supporting technical studies, including topographic surveys, subsurface utility engineering, geotechnical investigations, and arborist studies were also completed as part of the study to help inform the evaluation and detailed design.