The Phoenix | ELEMA - Structural Engineering Firm

This mandate consisted of the redevelopment of an existing building, a neglected warehouse dating back to the 1950s in the heart of the southwest borough of Montreal, in order to relocate all of Lemay’s operations. Since the building may be subject to future expansion requiring upgrading to seismic standards, the design of the lateral load resisting system was carried out during redevelopment to ensure its feasibility.

At the main entrance of the building, a new steel structure allowed the construction of a concrete walkway with an integrated angled ramp. Furthermore, a new opening in the existing floor was required to integrate the new architectural stairway, which is 100% concrete. At the roof level, a structural capacity analysis was required for the integration of 600 new photovoltaic solar panels. Finally, a portion of the basement was excavated to allow the creation of the new agora.

The building is certified LEED Platinum and Fitwel, the two most demanding standards, in addition to net-zero energy consumption and zero carbon practice.

Technical challenges :

The main challenge of this project has been the transformation of existing floors to accommodate new office spaces. The main transformations were, among others, composed of openings, staircases and an open space reception.
The main vertical circulation is by means of two superimposed concrete staircases with an explicit architectural design. The integration of these elements has been a particular challenge because of the lack of data in relation to the capacity of the existing structure.
The main entrance to the Phoenix is located in the former loading dock of the building to create a welcoming open space entrance facing the Lionel-Groulx metro station. The challenge of this transformation was the demolition of the existing structural slab followed by the construction of a new concrete floor integrating stairs and a diagonal ramp to allow circulation between the street elevation of the entrance and the level of the existing loading dock - a difference of elevation of 1 m (3 ft).
A life-cycle analysis was also conducted to determine the benefits of transforming an existing building instead of constructing a new one.

Notable solutions and innovations :

To accommodate the new stair openings, steel reinforcements were required. These reinforcements were composed of steel beams, connected by plates and anchors to the existing capitals of the columns. A particular procedure for manufacturing these plates was used because of the conical shape of the capitals.
Since the two superimposed concrete architectural stairs have a very large span (about 10 m or 33 ft), special attention was given to them in their design.
The architectural staircase between the ground floor and the second floor incorporates a steel beam at mid-span to reduce the thickness of the slab component. This beam is embedded in the central landing of the flight of stairs since the free height available under it was very limited.
The stairway between level 2 and level 3 was built in a single pour over a span of approximately 10 m (33 ft). This was made possible by using a tall reinforced concrete beam that supports the weight of the staircase and for which we have limited the deflections to the maximum in the design criteria. This tall beam, which also serves as a railing, has a trapezoidal shape to give it even more of an architectural character. Finally, since the staircase is made of exposed concrete, special attention was paid to the formwork to give it the best possible finish.