Over the Grand River in Ontario, Canada, Entuitive provided construction engineering services for the lateral sliding of the multi-span, 200-metre-long Highway 3 bridge at Cayuga and the replacement and widening of the Highway 401 bridges in Kitchener.
Recently, we sat down with Principal Stephen Brown and Principal Jason Jelinek to learn more about the Grand River bridge replacements.
Thanks for sitting down with us today, Stephen and Jason. Tell us about the projects.
Stephen: Both projects cross the Grand River and were with Dufferin Construction for the Ministry of Transportation (MTO). Besides both being Construction Manager General Contractor (CMGC) projects, they were very different. Cayuga was a five-span girder bridge replacing an existing truss preserving the existing piers, while the Highway 401 project is a multi-stage replacement of the existing bridge with a major widening and longer spans.
The contracting method is interesting. The CMGC process is intended to bring in construction methodology into the design, and the MTO uses this approach for some of their more complex projects. It allows the contractor approach to be “baked into” the permanent structure design and relies on a collaborative approach between the engineer of record, the MTO, the contractor, and the construction engineer. It is not a common delivery model in Ontario but it is a great one for projects like these, suiting the skill set we bring.
The Cayuga project was a lateral slide with the new superstructure constructed on temporary piers, the existing bridge demolished, and the existing foundations strengthened and then the superstructure moved laterally onto the existing piers. This approach provided continuous service until the existing bridge was taken down and the new bridge was moved in-place. We were the designers of the temporary piers, as well as the concept designers and engineers of the slide movement plan. It was a new bridge built off alignment that detours on and off, so that.
With the Highway 401 Grand River Bridge, we’re working on both the eastbound and westbound structures. The project includes the widening of the bridge, the addition of high occupancy vehicle (HOV) lanes, as well as the removal of the existing structures and the existing piers. Instead of a lateral slide with the structure, this project is primarily staged construction with longitudinal sliding of the girders prior to casting the deck for each stage. We’re keeping the existing structures in place as we build new piers on the side, launch the new steel girders on the new piers, and build deck, then shift traffic and demolish a section of the existing bridge, replacing it using the launch approach and repeating this sequence until the work is done.
Highway 3 Bridge at Cayuga – Temporary pier with lateral slide completed
What were some of the challenges you faced on these projects?
Jason: During construction at the Highway 401 site, we had to address the shape of the assembled bridge. The permitted tolerance for fabrication and assembly of the girders was greater than the tolerance afforded by the rollers at the various support points. As a result, girders frequently came out of contact with the rollers as the assembly was launched further into span. This required constant evaluation to ensure that there was no overloading at any of the rollers. Strategic plans were developed to loosen bolts in the diaphragms between the girders so that the assembly could comply to the positioning of the rollers while still maintaining stability for the girders.
Weather can also be a challenge at the Grand River. The river is active and prone to rapidly changing water levels. Icing is also a big concern during the winter months. When going into flood prone areas, it is important to use equipment that can be removed on short notice. This excluded the use of large cranes that would have been required for erecting the girders from the valley. Push launching the girders eliminated the need for having large construction equipment adjacent to the river.
Highway 401 – Girders approaching pier 3
Stephen: Almost a decade ago there was a dispute over the use of lands along the Grand River specifically for Cayuga Bridge since it is in disputed territory, which halted construction for about two years. Discussions and collaboration between the Government of Ontario and the Haudenosaunee Confederacy eventually permitted construction to be resumed with feedback from all parties, and the bridge was finally complete.
There is also an archaeological site at Cayuga just to the south on one of the abutments that we needed to be respectful of. The site was a stage 4 archaeological site and would have required excavation and was culturally sensitive. We developed our construction plan to not disturb the site. This required the addition of temporary retaining walls which had a significant expense but it allowed the site to remain undisturbed and the work to proceed much sooner.
What were your favourite part of the projects?
Jason: My favourite part of the Highway 401 project was being on site to see the tip of the bridge approach and land on the rollers at Pier 3. This was the critical point for the entire launch. It was satisfying to see the bridge do what it was supposed to do as the massive eight-foot-deep girders cantilevered 75m out from Pier 2.
Stephen: At Cayuga, my favourite thing for me was when it started to move, and it was apparent that it was going as planned. When well done, construction engineering can feel like watching paint dry in a positive way. If it is boring to tears, things are going well.
Do you have any final thoughts on the projects?
Stephen: For both projects, the level of collaboration and cooperation between the Ministry of Transportation Ontario (MTO), the owner, Dufferin Construction, the CMGC contractor, McCormick Rankin Corporation, the engineer of record, the designers, and the subcontractors was critical. We worked together well and the projects were better because of our collaboration.
Jason: The methods used to construct and move the new bridges into their final positions were markedly different at the two sites. In both cases, the construction methods allowed for brand new bridges to be built where existing bridges once were with almost no disruption to traffic on their respective roadways
Thanks for sitting down with us today! We learned a lot about the Grand River bridge replacements.