The design and coordination of the underground campus connection

between Comcast's global headquarters and its new Technology Center in Philadelphia was completed by Kelly Maiello Architects.  The project involved introducing a subterranean pedestrian tunnel through concourse service spaces in the existing building, under a garage ramp and across the street to connect to the new center. Concurrently, the garage ramp was demolished and rebuilt to meet new street grades while maintaining access to the garage during the phased construction. Effective long-lasting waterproofing of the pedestrian tunnel and ramp was paramount to the project's success, as there are finished public spaces beneath.

The tunnel site is bounded on the north side by the historic Arch Street Presbyterian Church, constrained by the SEPTA regional rail line directly below, and above by new streetbed. Challenges included "threading the needle" between existing foundations, waterproofing against multiple materials and conditions, and working with public and private agencies for the relocation of all major water, sewer, and electrical utility lines.  

Surface improvements included a refreshed Cuthbert Walk, including a beautiful new entry plaza for Arch Street Presbyterian, ADA accessibility, and new stone curbs and steps.