When you look at the Spring 2014 cover photo of PCI Journal (publication of the Precast/Prestressed Concrete Institute), you may be surprised to see a lot of steel.
The issue’s cover story is about the Mackenzie River twin bridges, a pair of two-lane bridges constructed using steel girders to support a precast concrete deck.
The bridges cross a deep gorge of the Mackenzie River as part of a new TransCanada Highway realignment near Thunder Bay, Ontario, Canada. There was considerable pressure to construct the two bridges as quickly as possible to prevent use of the existing congested highway by heavy construction vehicles. Various structural forms were considered. In the end, steel girders with a precast concrete deck offered the best combination of economy, expediency and aesthetics.
Each bridge has five variable-depth, corrosion-resistant steel plate girders that support the precast concrete deck, which is made up of precast concrete approach slabs and 130 precast concrete deck panels. The slabs and panels were connected at transverse joints and attached to the steel girders using field-cast concrete.
Read the article to learn more about how steel and concrete worked together as an innovative system for the twin bridges.