Alpine consults on six-story housing in Bellingham
Alpine Engineering has assisted on a new, six-story apartment building in Bellingham’s Bakerview Square, north of Bellis Fair Mall.
The project consisted of five stories of wood framing built atop an elevated post-tensioned concrete deck. During the build, Alpine provided on-site structural observations of the post-tensioned deck for the engineer of record.
The new building is a 40-unit apartment building with a mix of studio, one-bedroom and two-bedroom apartments. The ground floor, under the post-tensioned concrete deck, is a parking garage.
When the concrete deck was constructed in 2020, the Alpine team worked closely with the architect, contractor and engineer for construction conformance of the concrete deck. Plumbing, electrical, post-tension tendons, mild steel reinforcement and fire stops all had to be closely coordinated with each trade.
A post-tensioned deck consists of tensioned cables and mild reinforcement steel. According to the Concrete Network, the post-tensioning process reinforces concrete by pre-stressing it before any additional weight — in this case, five floors of living space — is applied. After the concrete is poured and while it is curing, steel tendons inserted through the concrete are pulled tight and anchored against the edges of the slab, pre-stressing the concrete to help it withstand the weight from above.
In a post-tensioned pour, all the concrete deck penetrations — for things like electrical conduits, fire flow conduit, water and sewer — must be carefully coordinated and cast into the deck. Coordinating all the locations of reinforcement and penetrations is mission critical, and Alpine assisted with that task.
The architect on this project was TRC Architecture. The builder was PM Construction. Ashley & Vance Engineering Inc. provided the structural engineering plans.
