Home Historical Sarnia’s History Marker: Blue Water Bridge Twinning Project

Sarnia’s History Marker: Blue Water Bridge Twinning Project

The Bluewater Bridge was originally built with two lanes for vehicles, and sidewalks for passengers on foot; later removed to make room for three lanes to be used by vehicles. The original solo bridge construction started in 1935. Prior to the twinning project, the customs and toll collection booths on both the American and Canadian side were extensively reconfigured in the early 1990s. The Americans added a four-story customs office building in the center. This entailed the demolition of the original booths that had been in used on the Canadian side since 1938. In 1992, bridge authorities determined that traffic on the bridge had exceeded its rated capacity, and decided to add a second span in order to accommodate the higher traffic.

Blue Water Bridge Twinning Project Created Public Debate

During the public discussion over the form of the second span from 1994-1995, five possible designs were proposed, with over half of public opinion favoring a duplicate of the first bridge, and a cable-stayed bridge coming second in votes due to its dramatic appearance. The Blue Water Bridge Authority had rejected both designs at the top of public opinion, due to the duplicate bridge creating a false sense of history, and the cable-stayed design would overshadow the existing bridge. The continuous-tied arch design, which place third in polls, was chosen because it blends in with the original span yet stands out on its own, and has lower maintenance costs because it involves fewer spans. With the continuous-tied arch lacking public support, engineers struggled with the challenge of making the two bridges now compliment each other, rather than creating an awkward look that critics believed to be the final outcome. They overcame this challenge by using concrete piers and steel tower supporting the anchor span, rather than the traditional concrete tower, to better ease the difficult transition between the approach, anchor and main spans. To make the main span of the bridge attractive, engineers settled on an innovative low arch design, to match the old bridge all while merging the traffic deck with the bottom supporting steel for the portion of the bridge suspended over the water.

American and Canadian Engineers Joint Efforts to Construction the BlueWater Bridge

The twinning project was a combined effort between American engineers, Modjeski & Masters and Canadian engineers, Buckland & Taylor Ltd. Due to each country’s manufacturing differences, the American engineers used six beams for each segment for the approaches while the Canadians used three box girders per segment. Despite this, the differing approach spans are identical from the side view. The second three-lane bridge, just south of the first bridge, opened on July 22, 1997.