Lahey Clinic Visitor Parking Garage
Precast with brick insets was chosen to provide continuity with the materials of the main facility and new additions that were completed at the same time as the Garage. The precast spandrels were heavily sandblasted to approximate the look of the original exposed aggregate precast, and the thin brick tile was carefully selected and placed in a random pattern to mirror the brick of the existing facility. The elevator / stair towers were glazed for patient safety and to serve as clear wayfinding elements for the reorganized campus. The elevator cores that sit within the towers were wrapped in a conventional brick that had to match both the inset brick spandrels and the original hospital building. Decorative light fixtures atop the precast columns help define the structure at night.
The superstructure of this 188 ft. x 534 ft., 4-level open parking garage consists of 48 ft. x 60 ft. typical structural bays and uses 12 ft. wide, pre-topped double tee beams with pre-topped girders and washes, internal K-Frame and horizontal Litewall shear elements and perimeter spandrels that are set into the inside face of the projecting columns. The three glass-enclosed stair/elevator towers of the garage are independent from the parking deck and they are connected to it by open pedestrian “bridges” at each parking level. A full-height “atrium” in each of the stair/elevator towers separates the stairs from the brick-faced elevator tower and acts to accentuate the height of the space and the openness of the stair and landings.
These design features presented significant lateral bracing challenges for the engineers, as the entire perimeter enclosure of each tower needed to remain visually open and unencumbered by any solid bracing and shear elements. The solution was to use precast concrete “tree columns” at the stairs which would allow the landings and risers to appear to cantilever in all four directions from a central supporting wall panel while using solid precast panels at the elevator towers to provide the necessary lateral bracing in the alternate direction. A supplemental steel tube frame provides backup for the glass curtainwall system and is tied back to the internal precast concrete lateral bracing elements of the stair and elevator core. The secondary stair was designed as a single, straight run between floors with arms of the tree columns supporting the stair run on one side of the wall and a full-length landing on the opposite side a each level. Large openings were placed in the central precast concrete supporting wall of this stair to further increase the openness, visibility and sense of lightness created by the tree columns at each end and the surrounding glass curtainwall.
Structural Precast Elements:
• Lightwall shear elements
• Pre-topped double T's
• Pre-topped girders and washes
• Tree Columns