This historic building, established in downtown Montreal, had been renovated in fast-track mode by integrating three levels below the pre-existing building. This project is a first of its kind in the types of work to be done, namely, the complete underpinning work of an existing building.
To perform the excavation, piles were drilled through the previous foundations, connected to the concrete columns already in place. We used the soldier piles technique as a permanent support for the ground pressures, according to the earth-pile shear wall principle.
The ground floor slab transfers all the load of the above columns with a "X-shape" transfer beams spanning 55 meters. Two levels above the existing construction as well as two floors of mezzanine were added.
Phase II consist of a 7-storey underground parking of 650 spots below the lower level of Phase I. The excavation was carried out using Berliner walls.