VANCOUVER — Design retrofits are moving forward for the Lions Gate and Ironworkers Memorial bridges in the Lower Mainland, the Ministry of Transportation and Infrastructure has reported.
A recent review of both bridges found they satisfy vessel impact criteria for new bridges of regular importance, explains a release, but they do not meet the criteria for new bridges of critical importance.
The review was conducted because of changes in vessels operating in the Burrard Inlet as well as updates to the national bridge design code. The study included consultation with the Vancouver Fraser Port Authority, the Pacific Pilotage Authority, BC Coast Pilots and the Transportation Safety Board of Canada.
The ministry is now aiming to bring both bridges up to the “more stringent” class for new bridges of critical importance in order to strengthen their resilience in the unlikely event of a vessel impact.
Known as Class 1 bridges, these structures are vital to the transportation network, the release reads, having an exceptionally small annual risk of collapse of less than one in 10,000. They are intended to be 10 times more reliable than regular bridges. Class 2 bridges are of regular importance, with a small annual risk of collapse of less than one in 1,000.
The scope of work for the two bridges includes the following.
Lions Gate Bridge: The existing concrete collar protection at the base of the south tower will be enhanced with an in-water rock-fill berm, the release reads. The north tower is already protected by a rock-fill berm.
Ironworkers Memorial Bridge: A steel barrier will be added to protect the trusses and in-water deflection structures will be installed close to the bridge. Design work is underway for an interim truss fender on the Ironworkers Memorial Bridge.
A Request for Qualifications has been issued for the functional design work, the release adds.
The Lions Gate and Ironworkers Memorial bridges have been in operation since opening in 1938 and 1960, respectively.
Approximately 3,100 vessels travel through the Port of Vancouver annually, including container ships, cruise ships, automobile carriers, tankers, bulk carriers and breakbulk carriers.
More than 140 million tonnes of cargo moved through the port, valued at $200 billion in 2017.