Wind climate studies and wind tunnel testing for a long-span cable-stayed bridge
The Port Mann Bridge is a cable-stayed bridge with a total length of approximately 6,600 feet. Its main span of 1,540 feet is the second longest main span of a cable-stayed bridge in North America. Upon its opening in 2012, the $3.3-billion Port Mann Bridge was also the widest bridge in the world.
In addition to spanning a substantial distance across the Fraser River, the bridge needed to provide over 138 feet of navigational clearance for shipping activity on the waterway below and be resilient to possible seismic activity in the region. Cable vibration was also an issue that warranted special attention, as the bridge’s design called for an unusual bundling of the cables supporting the bridge’s decks.
We provided a comprehensive set of services to help the bridge’s designers understand its safety and performance both during construction and after completion. These included:
- wind tunnel tests of sectional models of the bridge’s broad, parallel decks;
- a cable vibration study to understand how the unusual bundling of the bridge’s cables would affect their response to both wind and traffic;
- aeroelastic testing of the bridge at several construction stages and after completion, to ensure the safety of the structure at every phase of erection; and
- a detailed local climate study as well as climatic wind tunnel testing of portions of the stay cables, to understand anticipated snow and ice accumulation patterns on both the stay cables and the bridge towers, and to evaluate mitigation measures for falling snow.
The bridge was completed in 2012 and has been operating successfully since that time, with average weekday traffic of approximately 110,000 vehicles.