Patient Details
Alpha Structural performed extensive structural, foundation, and seismic upgrades to an existing non-conforming deck structure at this Los Angeles property. The project was designed to improve the deck's foundation and framing systems while incorporating code-conforming seismic elements.
The foundation improvements included removing the existing pad footings and excavating for three new 30-inch-diameter caissons. Two caissons extended to a maximum depth of approximately 6 feet, while the third extended to a maximum depth of approximately 11 feet. A new 24-by-24-inch reinforced concrete grade beam approximately 28 feet 4 inches long was constructed to connect and support portions of the new structural system.
Above the foundation, the existing weathered PSL beams were replaced with new high-strength HSS structural steel beams featuring welded connections and custom gussets. The new steel beams incorporated pressure-treated nailers to support the existing and newly sistered deck joists. A new pressure-treated ledger was also anchored along the building perimeter to improve the connection between the deck framing and the structure.
Seismic strengthening was incorporated through an engineered shear wall constructed along the front perimeter with new bolts, blocking, framing hardware, and structural shear paneling. The steel columns were also improved with new welded base plates and anchor bolts, with the easterly column plane designed as a code-conforming seismic system.
Additional structural work extended to the roof framing, where new HSS steel components were incorporated to support the existing roof system. Once the primary structural framing and seismic elements were completed, HSS tubes were installed for the rough handrail structure, leaving the finish railing components and other cosmetic finishes to be completed separately.
Together, the new caisson foundation, reinforced grade beam, structural steel columns and beams, sistered joists, ledger connections, and engineered shear wall provided a comprehensive structural and seismic upgrade for the existing elevated deck system.
