The Regional Municipality of York (York Region) needed to replace a culvert located on Major Mackenzie Drive West in the City of Vaughan, Ontario. The original culvert, which carries the West Don River under Major Mackenzie Drive, was about 50 years old and made of steel pipe. Major Mackenzie Drive had to be fully closed in order to safely and effectively complete the work to replace the older culvert with the new one. This had to be done over a period of two months to comply with restrictions with respect to environmental in-water work timing.
 
During the consultation period, the City of Vaughan requested that the project include additional pieces of City Infrastructure, which included another culvert. This second culvert would be used to create a passage under Major Mackenzie Drive for both pedestrians and cyclists and would eventually be linked to the new proposed trail system.

Precast concrete was selected for this replacement project because it offers the following benefits:

• Speed of Construction: The two culverts were manufactured in advance in a controlled environment which accelerated construction compared to cast-in-place construction methods. The culverts were manufactured even before the road was closed for construction. The culverts were ordered directly from the manufacturer through a tender process.
• Superior Quality: The precast concrete components were manufactured in a highly controlled CPCQA certified precast concrete facility which ensured superior quality of product, durability and a longer lifespan.
• Ease of installation: The installation process was completed on an accelerated building schedule since the completed precast concrete units were available on the construction site. The general contractor did not need to work around the clock to reopen the road.  

York Region contacted various precast concrete producers to receive input on the design and manufacturing of the culverts needed for the project and to ensure the structural integrity and minimize any potentials issues during the production phase. The culvert components also had to be ready as soon as the older culvert was exposed and ready for replacement.

In the spring of 2019, the precast concrete manufacturer, DECAST, was awarded the contract to design, produce and deliver the culvert units for the replacement project. The schedule to deliver the culverts components was incredibly tight. Both culverts had to be manufactured by the end of June 2019 to meet the aggressive eight-week construction schedule. It was imperative that the culverts were delivered on time because any delays could have resulted in longer road closures and potential significant financial implications. The design of the culverts was completed in consultation with York Region and the precast concrete manufacturer was able to meet the project timelines.

The precast concrete producer was also responsible for the delivery of the products to the construction site which was crucial in respecting the tight project schedule. The components were delivered overnight to reduce impacts to local traffic especially during rush hour. The experienced and highly knowledgeable team at DECAST shipped all 53 precast concrete pieces for the two large culverts in only five days. Major Mackenzie Drive was only closed for eight weeks from June 17, 2019 to August 12, 2019.

Project Details

The West Don River Culvert:

• 6,000mm (span) and 3,500mm (rise)
• Designed for an earth cover of 5 metres
• 29 precast concrete components were manufactured (38,800 kgs/piece) and an additional two pieces at 57,100 kgs/piece

The Pedestrian/Cycling Underpass:

•  6,000mm (span) and 3,000mm (rise)
•  Earth cover of 2.2 metres
•  22 precast concrete components were manufactured (37,755 kgs/piece)
   

In just eight weeks, the team accomplished the following:

• Excavate the current road embankment (8-metre-high) to uncover and safely remove the 50-year-old culvert
• Build a temporary diversion of the West Don River to have a “dry” construction site for the crew
• Utilize a large 600 tonne crane for the installation of the two new culverts (for the West Don River and for the pedestrian/cyclist passage)
• Redirect the West Don River to flow to the new drainage culvert
• Install a new oil-grit separator piece to treat storm overflow
• Install a new RSS wall (5-metre-high)
• Install and commission a brand new 400mm watermain connection
• Install an improved storm sewer system
• Restore the embankment and pavement for Major Mackenzie Drive

 
Photos 1, 2 and 4 courtesy of York Region. Photo 3 from CCPPA Concrete Pipe Journal (Summer issue).

 
Source: CCPPA- https://ccppa.ca/major-mackenzie-drive-culvert-replacement/ Article by: Jackson Marin, P.Eng. Project Manager, Capital Planning and Delivery, Transportation Services – York Region.