A Tale of Two Bridges: Extending the Lifetimes of the Lions Gate and Angus L. Macdonald Suspension Bridges

摘要

This paper examines similarities and differences between how the Lions Gate Bridge (LGB, opened in 1938 in Vancouver, British Columbia, Canada) and the Angus L. Macdonald Bridge (ALM, opened in 1955 in Halifax, Nova Scotia, Canada) were renovated and upgraded to address structural safety concerns and rapidly increasing maintenance costs. In both cases, parallel replacement bridges were not an option due to urbanization and/or property issues both ends of the bridges. In addition, neither bridge could be closed for long durations due to a lack of excess capacity in the local transportation network. As such, both bridges had to remain on their existing alignments while undergoing extensive rehabilitation and maintaining weekday daytime traffic. In both cases, superstructure replacement schemes were developed that allowed the superstructure to be sequentially replaced in segments during short night-time or weekend closures.This paper briefly describes the design features of both bridges, the scopes of work, similarities and differences between the erection works on both bridges, and the significant environmental differences between the two bridge sites. Importantly, lessons learned on LGB are noted, and how they were applied to ALM. Finally, the paper discusses the lessons learned on ALM and their applicability to future projects.