Teston Road expansion more than a simple road widening

With a population now well in excess of one million, York Region is experiencing tremendous pressure on its road network and that has been the catalyst for a number of expansions or proposed ones.

A prime example is the two-year, 2.2-kilometre-long, $49.3-million expansion of Teston Road, an east-west artery in the City of Vaughan, from just west of Pine Valley Drive to Weston Road.

Designed by HDR Corporation and being built by general contractor GIP Construction and Materials Limited, the project got underway in 2022 and won’t be completed until this fall.

Comprised of a number of diverse components, it is also more than a simple road widening.

The most complex of those elements was the July to December 2023 installation of a 45-metre-long, 26.5-metre-wide, single span bridge with a concrete deck on nine, 2.4-metre-high precast concrete girders over the local Purpleville Creek. The fabricator was DECAST Ltd.

Two large cranes, one 500 tonnes and the other 700 tonnes, were required to lift the girders into place, says the region’s engineering for capital infrastructure services manager Douglas Jones.

During that installation, Teston Road was closed and drivers had to use alternate routes. A portion of the bridge is now in place and is partially open to two lanes of traffic, one lane in each direction.

When complete, the bridge will carry two lanes of traffic in each direction and there will also be 3.6-metre-wide sidewalks on each side. Separating the sidewalks from the traffic lanes will be parapet walls which are now under construction.

A new bridge was necessary as the original 4.9-metre-long concrete box culvert was in very poor condition. But the new bridge ushers in other benefits, Jones says.

Installing the longer and higher replacement structure created a larger opening under the road which, in turn, opened up the valley lands and that will allow for improved passage of water, sunlight and wildlife. There will also be a 230-metre-long trail connection under the bridge.

Other parts of the project included realigning the creek channel, eliminating the jogged Teston Road/Pine Valley Drive intersection and a gradual rising of the road to five metres at the approaches to the bridge.

“The existing rural road had very constrained sightlines at this location. By raising the road, sightlines have been greatly improved and are now consistent with an urban arterial road, increasing safety for drivers,” he says.

Focusing on the technical details of that grade increase, Jones says it occurred incrementally and was achieved by way of a retained soil system panel wall system.

A first layer of wall panels was installed, anchored and backfilled. In a repeat sequence, subsequent layers were installed until the desired roadway elevation was reached, he says.

While the bridge erection was a complex procedure, so was the creek realignment which actually had to come first. As Purpleville Creek is environmentally sensitive with species at risk habitat for Redside Dace, work could only be performed from July 1 to Sept. 15, 2023.

Environmental permits had to be obtained from Fisheries and Oceans Canada, the Ontario Ministry of the Environment, Conservation Parks and the Toronto and Region Conservation Authority. As per the region’s standard policy on in-water work, prequalified stream contractors were used, he says.

The alignment sequence included installing the erosion and sediment control features, closing the road to traffic, then removing the road base to expose the existing culvert, and building a temporary channel east of the existing creek. With the channel in place, the old culvert was removed and a new permanent channel constructed “in the dry.” The final step was diverting the river flow back into the permanent channel.

As part of the project, the river valley is being restored in a series of initiatives. Some of those measures are already in place such as the creation of pocket wetlands with embedded grit separators and low impact development features, “which are already greatly improving the quality of water entering the valley.”

Other measures such as tree planting will occur once the bridge and road construction is completely finished, he says.

A major priority for the region throughout the project was minimizing the impact to residents. To achieve that objective, the road is being widened one side at a time. In 2023, work was focused on the road’s southern half, while two lanes of traffic were maintained on the north side. This year work will shift to the north side.

The need for the project was first identified in York Region’s 2009 Transportation Plan and then confirmed in a 2017 environmental assessment. Detailed design began in May 2017 and was completed in May 2022, says Jones.