February 9, 2011 – Strachan Avenue Overpass Strut Design Feedback
The polls closed on Sunday, February 27, 2011. To see the results, please click here.
As part of the Georgetown South (GTS) Project, we are removing the level railway crossing at Strachan Avenue. The rail corridor will be lowered between Bathurst Street and King Street West, with the lowest point under Strachan Avenue. Strachan Avenue will be slightly raised above the corridor.
On October 26, 2010 we hosted a Design Update to review the plans with the community, including a detailed look at how the lowered rail corridor would look once built. The design includes a series of struts running across the lowered rail corridor roughly from Stanley Terrace to Shaw Street.
In response to feedback received at the Design Update, we committed to providing different strut options for comment. We are now ready to share the design options with the community – but first, some background.
What is a strut and why is it being used?
Struts provide outward-facing support. Retaining walls are required for the lowered rail corridor. Struts will span across the corridor to support the north and south retaining walls from the section between Stanley Terrace and Shaw Street.
Are there alternatives to struts?
Yes. We did review the use of cables – or tie-backs – instead of struts in this section. Tie-backs are cable extensions driven into the earth at a 45 degree angle to support the retaining wall.
However, this option has significant property impacts requiring permanent easements under the properties where the tie-backs would be installed. This permanent easement would limit the type of use on the property above the tie-back.
With the significant depth and width of the lowered rail corridor, struts are the best option to maintain structural integrity while minimizing property impact.
What we heard from the Community
The community asked us to explore if the struts could be designed to incorporate architectural elements that would reflect the overall aesthetic of the surrounding community;
it was even suggested that the strut design incorporate elements of the new Fort York Pedestrian Bridge. We
collected all the comments and shared them with our design team.
Design Considerations
As explained at the October Design Update, the design of the struts is subject to certain constraints, including:
- Structural Support – The size, material and spacing of the struts are determined by the load requirements they are designed to support.
- Maintenance Free – The struts should require little to no maintenance, so we should avoid curvatures that would trap rain or snow, or greenery that would require upkeep or pruning.
- Budget – The overall cost of the Strachan Avenue Overpass must be within an approved budget.
- Schedule – There is a firm construction schedule. The entire GTS Project must be completed by the end of 2014. Any strut design must meet the construction schedule.
Strut Options for the Strachan Avenue Overpass
Working within the design considerations listed above, our design team developed new strut options. The original strut design shared in October included straight horizontal supports connecting the north and south retaining walls. These struts were 2 to 3 metres apart with a centre wall that supported both the struts and the bridge.
Here are the options inspired by your feedback.
Teardrop Lattice |
Diamond Lattice |
Standard Struts |
Washboard |
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