Keele subway spicy concrete

Text from the TTC's planning statement

The structural upgrades will generally consist of the construction of five new piers within the parking lot to provide additional support of the bridge deck. All work will be conducted within the property of the commuter parking lot.

A large drilling rig will be used to auger 10 large diameter caisson holes located outside of the bridge structure; 5 holes on either side of the bridge. The caisson holes will be drilled below grade to a depth of approximately 18 metres with a diameter of 1.8 metres.  In this regard, the augering, the installation of reinforcement steel cages and placing concrete into the holes will be conducted primarily during the daytime hours however, work may extend into the evening hours in order to complete key operations associated with the caissons.

Each pair of caissons will be joined by excavating the area between 2.2 x 3.0 x 13 metres and placing concrete to grade level to form a concrete beam over the caissons.  A steel frame will be placed and permanently rest on each beam, which will be jacked up to the underside of the bridge to provide added support.