The redevelopment of Philadelphia’s Gallery Mall is a massive 1.5 Million SF interior and exterior renovation that encompasses 13 different structures, spans three city blocks, and sits on top of four different mass transit train lines. The project was broken up into four different sections and carried out of the course of seven years. Upon completion, it is the “largest cohesive retail project in downtown Philadelphia.” ..

The redevelopment of Philadelphia’s Gallery Mall is a massive 1.5 Million SF interior and exterior renovation that encompasses 13 different structures, spans three city blocks, and sits on top of four different mass transit train lines. The project was broken up into four different sections and carried out of the course of seven years. Upon completion, it is the “largest cohesive retail project in downtown Philadelphia.”

The goal of the renovation was to transform the space from an enclosed, subterranean shopping and transit center to a major destination for retail and entertainment in Philadelphia. Creating new connections and a light filled space that is more easily accessible and welcoming. The new main entrance at 9th and Market Streets, a feature of the renovation, provides an iconic welcoming area comprised of 170 panels of structural glass.

The new main entrance, the Cube, is a freestanding structure with a clear height of 60 feet. Comprised of steel trusses and built-up box column sections it features architecturally exposed structural steel, while the roof cantilevers 23 feet. The Cube is also a column-free space with a 68-foot clear span. Site challenges for the new main entrance included extensive foundation work to infill the previously below-grade entrance including carbon fiber reinforcement of an existing reinforced concrete wall to retain soil as well as new retaining walls.

Keast & Hood provided structural design for the new feature entrance as well as modifications to the structural frame in each segment of the building complex for a more open and easy to circulate space. One of the main goals of the renovation was to increase lighting levels throughout the complex. To accommodate this, multiple large sections were cut into the Ground floor to allow for more daylighting. At one of these openings, a 72-inch deep transfer girder existed supporting one of the building columns and thus had to be removed. To do so, engineers re-supported the building column with a new transfer beam located one floor down. This necessitated a complicated construction sequence involving temporary hydraulic jacking, done while there were six occupied stories above, to redirect the building column loading directly down into the post-up, and onto the new transfer beam below. In another section of the complex, one of the historic structures utilized cast iron columns. The floor in this section was lowered to increase accessibility for commuters by removing the need for stairs at that entrance. Engineers encased the cast iron columns in concrete and the floor was lowered while the offices above stayed occupied and the connecting mass transit rail lines of PATCO, the Market Frankford Line, SEPTA Broad Ridge Spur, and SEPTA Regional Rail all stayed in operation and undisturbed throughout the entire project.

Structural design for the support of new exterior wall systems, canopies, and large-format signage and new interior escalators, elevators, and stairs was included as well as design for the support of primary mechanical equipment such as air handlers, boilers, chillers, and cooling towers. Keast & Hood is also providing the structural design for many of the tenant improvements such as internal stairs, escalators and elevators. A major tenant is the AMC Theater. To accommodate the large space required by the theater, engineers designed a 44-foot overbuild and extensive reinforcement of both the gravity and lateral systems of the remaining structure. Engineers also studied the potential for vertical expansion at several areas of the complex. On the complex’s exterior, the existing precast concrete panels were removed and replaced with large metal panels, brick along Filbert Street, and glass entrance vestibule to allow more light into the building. Engineers added girts along the perimeter of the building to support the new glazing. For this project engineers utilized HSS girts which spanned between the existing columns roughly 30’. With the top to bottom redesign of the multiple sections that make up the Fashion District, the space is now a light-filled, easy to navigate destination that exists in stark contrast to its previous iteration.

CLIENT: JPRA Architects
LOCATION: Philadelphia, PA

TYPE: Commercial, SERVICES: Renovation, MATERIALS: SUSTAINABILITY: . . . . . . . . . . . . . . . . . . . . . . . .

Construction project photography © Jeffrey Totaro, 2017 Final Photography © Halkin Mason Photography