Construction on the Davenport Diamond Guideway project is, in a very real way, ramping up. Recently, reinforced concrete columns have been popping up as they form structural piers to support the elevated guideway. Next, community members will see even more activity above ground as crews build the mechanically stabilized earth (MSE) walls at the north and south ends of the project. The engineering behind these ’MSE’ walls is fascinating.
Sometimes, a large mound of earth can hold a great many secrets – of science and advances to important improvements in GO Transit.
Let’s reverse engineer the strength and powers of ‘mechanically stabilized earth’ (MSE) walls now being built at the ends of Toronto’s Davenport Diamond Guideway project.
Just over a year into construction and the Davenport Diamond Guideway project is taking shape and becoming more visible with each passing day. The guideway project is part of Metrolinx’s GO Expansion program, providing future two-way, all-day service on the Barrie GO line. When complete, it will span between approximately Bloor Street and north of Davenport Road – alleviating train traffic by allowing GO rail service to travel above freight trains.
To date, efforts have been focused below ground such as caisson drilling, structural support, and ground improvement. Now things can start to build up and above ground.
MSE walls are massive soil structures that pave the way up to the elevated guideway. The highest point of the guideway is about nine metres from the ground –over the CP Rail tracks. It’s like a really big ramp made of reinforced soil designed to support the weight of the trains passing above.
An MSE wall is essentially a huge pile of soil that has been strengthened by placing reinforced straps in horizontal layers throughout the height of the wall and is connected to pre-cast concrete panels.
The panels fit together like puzzle pieces to keep everything locked in and adds a nice touch by improving its appearance. The combination of the panels and the straps allow the wall to be built with a near vertical face because of the support created by the tension of the straps.
Here’s an infographic of an MSE wall.
There are two MSE walls on the Davenport Diamond Guideway project. The south MSE wall, from Bloor Street to Wallace Avenue, and the north MSE wall, from just north of the CP Rail tracks to approximately Davenport Road. The elevated guideway will be built in between the two walls.
Construction on the north MSE wall will begin later in June and last a few months, while construction on the south MSE will start later this year.
MSE walls are typically used when space is limited and when a slope made of soil would not naturally hold on its own. MSE walls are a great solution for when there isn’t enough room and a slope is required to create a change in the grade for roadways and railways.
At Paton Road, the pedestrian underpass that connects the community will be built directly through the south MSE wall.
You can also connect with the community relations team at TorontoWest@metrolinx.com.
Interested in the Davenport Diamond Greenway project? You may have missed this recent story.
Story by Teresa Ko, Metrolinx communications senior advisor