Trillium Building - Temporary Retaining Wall, Halifax, NS


The Trillium Building is a 19 storey structure featuring condominiums and three floors of underground parking. Excavation for the foundations and underground parking levels had begun when the contractor had to stop work due to unstable soil conditions.

This project was particularly challenging due to the extremely close proximity of existing buildings, underground services, adjacent city streets and sidewalks, short schedule and difficult geotechnical conditions. After the owner approached several other firms, HEC was the only local consulting firm to provide a solution for this technically challenging project. 

HEC was able to respond quickly with an efficient design that allowed the contractor to continue work while minimizing impacts to costs and schedule.  The design included two 3.2 m high timber lagging walls consisting of steel soldier piles grouted into bedrock, timber lagging and horizontal steel walers with 25 mm diameter rock anchors that projected below the existing adjacent buildings and roadways. 

Client: Maritime Testing Limited

Value: $0.5 M (Approximate, Temporary Retaining Wall only)

Year: 2009

Role: Structural Design Engineers