July 9, 2020
DPR Construction used prefabricated modules from Digital Building Components to build temporary bypass hallways to minimize the impact of construction at a major hospital in the Phoenix area. The expansion project will add approximately 580,000 sq. ft. to the existing hospital building, with construction to be completed adjacent to the current Emergency Department (ED).
“We needed to perform major construction work while the busy emergency department remained functional,” said DPR project manager Mike Cummings. “Patients and staff needed access to the hospital, but the building expansion couldn’t be completed without moving the entrances.”
The enclosed walkways routed pedestrian traffic to the hospital’s entrances, allowing patients to access critical care services while reducing disruptions. One hallway provides public access to the ED while the other provides ambulance and helipad personnel access.
With a combined length of approximately 700 ft. and interior dimensions of 8 ft. x 8 ft., each hallway was designed to ensure the comfort and safety of those who use them throughout the two and half years of the construction project. The prefabricated hallways meet stringent code requirements including a two-hour fire-resistance rating in the case of an emergency.
Several building methods were considered for the hallways. Cummings said the project team looked at traditional onsite construction, onsite fabrication, and offsite fabrication. All three options had similar costs, so the project team looked more closely at other factors: safety, on-time delivery, and impact to the hospital staff and patients.
The project team chose offsite prefabrication with components manufactured by Digital Building Components to best meet customer needs. Specifically, this method was projected to reduce the overall schedule by an estimated three weeks. The onsite team could pour concrete foundations to support the module components while the hallway sections – fitted with mechanical, electrical, and HVAC elements – were built in the fabrication shop.
“It took a lot of detailed and upfront coordination with our trade partners, but we were able to cut the installation time in half from what was anticipated for a traditional ‘stick-built’ system,” said Cummings. “This meant less disruption to patients and hospital operations.”
He notes that prefabrication wasn’t used for the entire passageway. The project team analyzed existing conditions and determined that a traditional construction method was more appropriate at the ends of the hallways. Canopies at the connections to the building meant cranes couldn’t drop the modules into place, so those sections were built conventionally. “We used prefabrication where it made the most sense and increased our productivity,” explained Cummings.
The productivity during installation far exceeded expectations and showed off the benefits to building some components offsite. Digital Building installed roughly 12 units a day and completed 47 in four days totaling roughly 520 linear feet with a crew of four. In the end, using prefabrication sped up completion of the temporary hallways by about five weeks and reduced onsite labor by approximately 2400 worker hours.
“We had been considering prefabricating other elements on the hospital too,” said Cummings. “After the successful hallway installation, the value was clear. We received customer approval to move forward with prefabricating the exterior wall panels.”