The original building had actually been sinking because its foundation did not have sufficient compaction and drainage. By replacing the entire ground floor slab, the building’s foundation has been strengthened, ensuring it will last for another century.

Other seismic strengthening scope included fiber column reinforcement, shotcrete shear walls, steel zipper columns at existing braced frames, collector strengthening and micro-pile foundations.

Photo by Jason O’Rear

The roof’s existing 3-in. concrete slab was reinforced with steel beams designed to support the heavy terrace’s dead and live loads. Steel beams were placed below the existing roof structure to minimize overall building height to meet the city’s maximum height limitations.

A three-level glass box stair begins on the second floor and climbs up to the rooftop terrace. The centrally located stair is built within a frameless glass box. Weekly meetings were held with the architect, structural engineer and contractor as well as structural glass and metal fabrication subcontractors to address the intersections and relationships of the various materials that make up the stair. BIM 3D modeling helped the team streamline installation and resolve any conflicts.

The roof deck was designed as a space where tenants can relax, unwind and take in views of the city. The roof also houses the air handling equipment.