Ottawa witnessed another feat of groundbreaking technology over the long weekend in July, when R.W. Tomlinson replaced the Queensway’s Carling Avenue eastbound and westbound bridge in less than 16 hours.

The operation, which with conventional methods takes two to three years to complete, was a result of more than a year of hard work and planning, and was a prime example of rapid lift technology at work. From 6 p.m. on July 30 to 9:45 a.m. the next day, R.W. Tomlinson closed all lanes of the Queensway to replace the bridge’s outdated decks with newly constructed ones that will allow for the future expansion of the highway.

Since May 2010, R.W. Tomlinson crews had been working to widen and rehabilitate the existing substructure, as well as construct new bridge decks in our staging area. Faced with extremely restricted access and strict operational constraints, here are some of the challenges we faced:

• We needed to keep the vibration caused by our construction down to a low 15mm/sec due to a nearby 1200mm watermain that feeds a large portion of Ottawa’s population. We also needed to install a monitoring system to make sure the level was never exceeded.
• Due to the proximity of both the Queensway and the watermain, we needed to install an extensive shoring system to allow us to widen the existing abutments. This needed to be done in four stages in a very restricted area, while maintaining traffic on the Queensway and Carling Avenue.
• It was imperative that the construction of the staging area to accommodate the construction of the new decks on temporary supports would allow free movement in and out of the staging area for the 
self-propelled modular transporters.
• Precise surveying was required to ensure clearance for transporting out the old decks and, more importantly, to build the new decks to fit onto the old abutments.

The highlight of this project was the replacement of both bridge decks with the self-propelled modular transporters (SPMTs). By using the SPMTs, we were able to limit the travelling public’s exposure to 
any construction activity to only a few weekends of lane closures and 15 1/2 hours of full closure of the Queensway.

The two existing decks, which weighed up to 499 tonnes, were prepared for removal early Saturday morning while traffic continued to flow in both directions on the Queensway. At 6 p.m., all lanes were closed to allow the remaining excavation to be completed so that both bridge decks could be lifted and transported to the staging area.

Within an hour and a half of closing the highway, the existing westbound deck was on its way to the staging area. Within four hours, both bridges had been removed and the new widened decks, weighing up to 714 tonnes, had been brought in and were undergoing final adjustment.

Immediately after the decks were placed by our structural crews, our grading crews went into action. Within four hours, they had them ready to be paved. To assist in the speed of our paving operation, we used a new type of asphalt called warm mix. This asphalt is mixed at a lower temperature than conventional mixes and reduces the time needed to allow traffic onto the paved surface. The success of this project is entirely a result of the terrific co-operation and dedication of everyone involved.