Michael Lewis
Special to Ontario Construction News
Toronto has approved a plan it says will accelerate reconstruction of section 2 of the aging Gardiner Expressway, a project causing major gridlock for commuters. The plan adds crews and demolition equipment, extends working hours — and relies on offsite prefabrication of deck panels and girders and other accelerated bridge construction technologies.
“Prefabrication is a critical component of the planned reconstruction of the expressway,” the city’s chief engineer said in a report submitted to city council on Wednesday.
Council unanimously approved the plan that could reduce the projects’ timeline to two from three years, agreeing to amendments envisioning accelerated approaches for other city building projects and to ensure the safety of workers who will be working overnight and in winter.
City council’s approval follows the Ford government’s announcement that it would provide up to $73 million to help cover added costs for streamlining the project under a contract awarded last year to Grascan Construction Ltd. with a budgeted price tag then of $300 million.
The report does not detail additional costs or if any trade-offs will be required to meet the accelerated schedule.
The section 2 project requires rotating lane closures on the expressway that the province says carries about 140,000 vehicles per day, reducing overall capacity by about a third.
Ontario Transportation Minister Prabmeet Sarkaria said under the updated timeline the reconstruction will be completed by at least April 2026 from April 2027.
The province is providing funding on the condition that work be allowed to proceed on a 24-7 basis, with the cash to support changes intended to improve traffic flow in the area.
The scope of the section 2 work involves the full demolition and rebuilding of 700 metres of the elevated downtown expressway, with the existing deck of concrete and steel girders to be replaced by precast concrete box girders. The work requires 705 precast concrete boxes to be made offsite in parallel with ongoing demolition, the engineer’s report said.
Work also includes rehabilitating the associated substructure and installing new street lighting between Dufferin St. and Strachan Ave.
The work is a component of a six-section, $2.3 billion project to save the 18-kilometre expressway that is approaching the end of its original design life.
The first phase between Jarvis and Cherry streets, also using accelerated bridge construction technology, was completed in 2021.
Between 2014 and 2016 Toronto city council approved the Strategic Rehabilitation Plan for the expressway from Highway 427 to the eastern limit at the Don Valley Parkway, including the 11 kilometre at-grade section from Highway 427 to Dufferin with its 32 bridges and structures, and the seven km. elevated section from Dufferin to the DVP with 335 spans.
Rehabilitation of the elevated downtown portion of the Gardiner, technically Ontario’s longest bridge, follows extensive repairs that became necessary in the early 1990s when chloride-induced corrosion caused spiralling concrete to fall off.
The city has considered proposals to demolish or move Gardiner East underground as part of downtown waterfront revitalization efforts, opting for rehabilitation given costs and commuter and commercial reliance on the high-speed artery.
Toronto has set 2030 as a tentative deadline for completion of the entire Strategic Rehabilitation project, which is already behind schedule in part due to pandemic related shutdowns.
Several Torontonians took to social media to express doubts about whether the project will actually be completed a full year ahead of schedule.
Among a series of measures, the plan calls for faster production of the girders to ensure they are ready for installation in accordance with the stepped-up schedule. In addition, following a recent industry expert workshop, the staff report said changes to the design of some girders will shorten the time it takes to install them on site.
Virginia-based bridge construction infrastructure technology provider Parsons Corp., technical advisor on the section 2 project, said accelerated bridge construction using prefabricated concrete panels could allow replacement of the west deck 27 per cent ahead of schedule.
“The Gardiner is 60 years old, and we need to rebuild it,” Mayor Olivia Chow said at the council meeting.
“We know that we need to make it faster,” Chow said, suggesting that downtown residents can expect more noise overnight in the interest of reducing congestion. The acceleration plan says the city is monitoring noise and will strive to restrict loud demolition work in populated areas between 11 p.m. and 7 a.m., though there are no specific restrictions.
“We’ve heard the anguish some of the folks are feeling because of the traffic congestion,” Chow said.
“It’s a really complex project that is …. impacting people’s ability to get around, so the city has been working to find ways to accelerate this rebuild.”
The city engineer’s report said the acceleration proposal includes additional crews of workers, extending working hours, additional equipment for faster demolition, temporary lighting for additional night work, additional equipment to facilitate concrete curing in winter, additional winter heat and protection and additional snow and ice clearing.
It requires modifying techniques for removing steel girders, securing additional precast beds for fabrication of precast concrete box girders, along with accelerated fabrication and delivery of bearings and expansion joints.
It also sees accelerated rebar production, additional parapet wall forms, extending hours of concrete and asphalt plants to facilitate deliveries outside of regular operating hours, and asphalt, waterproofing, and line-marking premiums for winter operations.