Children's Hospital of Philadelphia Buerger Center for Advanced Pediatric Care

The difference made by a unitized approach

During the bid/proposal process, Turner recognized that one of the project’s largest challenges was associated with the exterior wall construction. The original design for the exterior wall would have required the use of as many as six different subcontractors, all attempting to coordinate work on the building’s ever-changing geometry. In order to overcome the challenge of building such a complex wall system, reduce/eliminate the potential for leaks at the multiple trade interface locations, and have one subcontractor responsible for the geometry and interfaces between the materials, Turner introduced the possibility of changing the wall construction to a unitized curtainwall system. During the contract negotiation phase, Turner teamed with Enclos (curtainwall subcontractor), CHoP (owner), FKP (architect), Pelli Clarke Pelli (architect), and the project’s exterior wall consultant to review all the parameters associated with changing the wall system. After multiple teaming sessions to review all details of the proposed curtainwall, its loading of the structure, and its impact to interior fit-out and finish construction, an agreement was reached that using a unitized curtainwall system had benefits over the original design and could be incorporated into the project. As the wall was constructed during the period from October 2013 to September 2014, water infiltration tests were regularly performed. We believe the reason all these infiltrations tests passed on the first attempt was due to the changes that were made by the team to adopt the unitized curtainwall system. This critical change in construction technique maintained the original design intent for both the exterior and interior of the project and maintained the vision for the building that the Owner had shared with all of its stakeholders. Yet, because of the significant reduction of subcontractor interface, the construction was simplified, potential leak points were drastically reduced, and both cost and schedule were maintained.