Structural Engineers

Another residential row-housing renovation with Bonstra | Haresign Architects imposed some unique design challenges.  The project called for cantilever balconies at the rear of the building, as well as the basement level to be dropped several inches to accommodate a greater floor-ceiling height. 

The Challenge

The basement level of the building was proposed to be lowered, creating some difficult underpinning conditions.  Also the building had a cantilever at the second floor over some above-grade parking and the client had proposed cantilever balconies to span out from that cantilever and at the floors above, which caused some difficulty when framing out these cantilevers.

The Solution

To alleviate the basement slab situation, underpinning was provided under each basement wall using epoxy to anchor rebar into the existing foundations.  This, in turn, tied the existing structure into the new underpinning below and prevented any sort of hinge-action at the face where existing meets new.

The cantilever balcony was difficult to frame, and after initially proposing hanging the balconies from steel framework above, together with the architect, we agreed upon a solution of using steel rod tie-backs to support each balcony while adding an aesthetic appeal to the structure.

The Takeaway

By coordinating with the architect, Structura created a unique structural solution to support the balconies and existing walls, while also appealing to the client’s tastes.