Project Tour : Cambridge Apartments Renovation

• Emmanuel Diaz
• Project Engineer
• Rafn Company

The Cambridge Apartments renovation project consists of a complete seismic retrofit to the 10-story turn-of-the-century building as well as a full plumbing infrastructure replacement, new lighting wiring, new fire sprinkler system, unit renovations, and elevator modernization. The building is partially occupied during construction and provides 157 units of affordable housing on First Hill in Seattle. Construction is well underway with a target completion date in the Fall of 2018.

STOP 1 : Excavation for New Concrete Shear Wall Footing Due to the limited work area, we accomplished the excavation for the new footings by hand digging down to a depth of 7 feet below the existing slab. We will also be installing new concrete footings and a ground water remediation system in this area.

STOP 2 : Boiler Room Demo Located at the mezzanine level of the building, the boiler room demolition consists of removing existing walls and the concrete slab so new concrete footings and shear walls can be constructed. Like Stop 1, excavation will take place after demolition for installation of the new concrete footings.

STOP 3 : New Slab on Grade Level 3 Bringing together the process from stops 1 and 2, we demolished the existing walls and concrete slab to excavate for new footings. Due to the depth of the existing footings, the new footings were redesigned by the engineer to sit on 34 micro piles. The new concrete shear walls sit on top of the new footings and go up through the building to Level 8.

STOP 4 : New Concrete Shear Walls Directly above Stop 3, in the residential units of the building, the concrete shear walls make up a common wall between two units as they go up to level 8. As the last step in the sequence, we will cover up these walls with drywall and paint so they blend into the existing structure of the building. This process (Stops 1-4) will be repeated in the building at two locations for a total of 6 new concrete shear walls.

STOP 5 : New MEP in Shafts Working inside of the existing utility shafts we are installing new mechanical, electrical, and plumbing (M/E/P) to bring the systems up to modern standards. A limitation allowing no more than 40% of the shaft walls to be removed for new M/E/P work makes for a challenging installation. We will finish this work by installing metal framing and drywall so the shafts blend back into the existing walls.

STOP 6 : Corridor Soffits for New M/E/P We are in the process of installing a new corridor soffit to conceal new electrical wiring, phone cables, and fire sprinkler lines. We removed the existing historical trim in the corridors and stored it for reinstallation around the new soffits when complete. Soffits will eventually be installed on both sides of the corridors when work begins on those phases.

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