Benchmark West Alex is a nine-story senior living facility located at the ‘West Alex’ complex at King and Beauregard in Alexandria, VA. The complex contains a shared two-story below grade parking garage supporting two residential buildings, ground floor retail space, and exterior landscaped plaza. The new building is located atop the existing below grade parking structure. The building will provide assisted living and memory care for residents and ample space for activities/programming, private events, and amenities. A landscaped rooftop terrace and penthouse offers sweeping views of the Washington Metropolitan area.
The existing structure consists of a conventionally reinforced two-way concrete slab with drop panels at the ground floor and P1 level with spread footing foundations. The initial base building design anticipated a seven-story steel-framed office building above the ground floor. The below-grade structure was designed for the assumed office loading and superstructure layout. When the design was modified to a residential building, the existing building column layout did not work with the programming needs for the residential use and most of the superstructure needed to be transferred. To accommodate this, a transfer slab was introduced at the second floor, consisting of post-tensioned transfer girders located underneath building columns above.
Strengthening was required for the existing columns and foundations to accommodate the loading and revised layout of the new superstructure. Spread footing enlargements were introduced with column jacketing below grade to accommodate the additional loading. Careful attention was also required for the below-grade strengthening, as the garage needed to remain fully operational during construction.