Stamford Hospital's project team had nearly finished design and preconstruction work on a new three-story facility to house emergency, surgery and acute care services when the client added a request: Add a seven-story tower that the master plan did not specify for another decade.

It was not the first twist—but may be the most momentous—in an ambitious effort to reshape, modernize and expand Stamford Hospital through a $450-million project that broke ground last year and is set for completion in spring 2016.

New York's Skanska USA Building, Houston's WHR Architects and the rest of the team turned on a dime to integrate the new scope in a project that will add a 640,000-sq-ft tower, a new central utilities plant and advanced medical theaters.

When the hospital reset the scope four years ago, the project team had to develop a plan that would keep already designed portions within the programmed budget, says Paul Nylund, senior vice president at Skanska, the construction manager. "The lower part had been 80% designed, but the rest of the building had different levels of design information," he says. "They had a fixed budget, and we had to determine what that [tower] cost would be without the job being fully designed."

The new work added to already complicated logistics for a fast-tracked job with overlapping phases, a major transition of utility services, a complex parking relocation puzzle and a constant struggle to not disturb the sanitized hospital environment. The job will ultimately expand the hospital campus footprint by 50%, but not before reshaping nearly every facet of the site, Nylund says.

Big Plans

Stamford Hospital had adopted its new master plan in 2007, says Joel Colwell, principal at WHR, the architectural firm guiding the planning effort. "It was a very inefficient campus with services strewn across the 20-something acres," he says. "The campus is a series of old buildings, [some] dating back to the 1920s."

The plan called for a series of property swaps and purchases to increase the campus size to 30 acres as well as to modernize and expand key facilities and to shift to a private-room format.

Many of those elements are in the new project, which is adding 10 operating rooms; a 24-bed intensive care unit; a 27,000-sq-ft heart and vascular care center; a 45,000-sq-ft, 48-bed emergency department that doubles the unit's treatment capacity and adds a pediatric care area; 180 single-patient rooms; and a separate 33,500-sq-ft boiler, chiller, gas, oil and electrical plant.

The project's heart is the steel superstructure tower with concrete-on-metal deck floors, on which the team began construction last fall and topped off in May, says Stan Hunter, director for the master facilities plan at Stamford Hospital. The team has since started on the 250,000-sq-ft curtain wall—which is prefabricated in floor-to-floor pieces, including 2,800 unitized panels—and has begun major mechanical and ductwork as well.

"We're moving to get weather-tight for the winter," Hunter says. The final tasks next year will involve fitting out the new medical spaces with modern equipment.

The job's staggered phases have gone smoothly, Hunter says, because of a healthy team atmosphere among the lead firms, which include Skanska, WHR, Walter P. Moore as structural engineer and BR+A as MEP engineer. "We have open and continual dialogue, and that's been really important," he says.

The early phases of construction involved multiple layers of tasks around excavation, utility relocation and foundation work—a theme of overlapping stages and sequential steps as the job progressed, Nylund says.

"It was very complicated logistically," he says. "There was a lot of 'You can't do this until you do that.' We had connections to the old central plant that we couldn't remove until we had the new plant. Some of the new utilities ran through the footprint of the new building. Some entrances to existing buildings [had to be rerouted]. And we had to keep moving the parking areas—that was always challenging."

Site contractor John J. Brennan Excavation, mechanical contractor Harry Grodsky & Co. and electrical specialist SEMAC Electrical Contractors coordinated closely for the 85,000 cu yd of excavation and intensive utility work. To give the new plant—which includes a 5-megawatt back-up generator—a lower profile, the team dug deeper on the sloping site, sinking it 40 ft underground at one end and 20 ft at the other, Nylund says.

The team broke ground on the plant in September 2012 and completed it in 15 months, Hunter says. But the old plant, which sat 250 ft north of it, remained on site while the team rerouted all of the utility connections, a 15-stage effort completed this year.

That timing created a bottleneck on constructing the tower, which would rise on the site of the old plant and had utilities crossing through its foundation. The team decided to get started anyway, breaking ground on the tower last summer, Hunter says.

"We built around the old central plant as much as we could, so by the time we took down that building in February of this year, we had steel on parts of the new building up to the third floor," he says.

The project team also used business information modeling technology extensively during the central plant construction, which helped the subcontractors detect and avoid many potential clashes.