Jun 24, 2013
An extensive prefabrication strategy aims to keep the $1-billion University Medical Center project in New Orleans on target to meet the project's daunting scope and aggressive construction schedule. With more than 2 million sq ft of built space, the project for the state of Louisiana is one of the largest health care campuses under construction in the U.S. Its 31-month construction schedule has prompted construction-manager-at-risk Skanska USA Building, New York City, and joint venture partner MAPP Construction, New Orleans, to pursue prefabrication of mechanical systems, headwalls and bathroom facilities.
Across the 38-acre site, crews are moving fast. With a targeted completion date in spring 2015, the jobsite is running 20 hours a day, with up to 1,500 workers spread across two shifts. According to Ralph Easterwood, Skanska general superintendent, the building team is completing roughly $1 million worth of construction each day.
To help keep pace, almost 40% of the mechanical systems at the project site are being prefabricated in racks up to 8 ft wide and 20 ft long. Each one of the 1,100 racks contains HVAC ductwork, utilities, piping, cabling and relevant mechanicals for each floor.
Mike Austin, senior project manager at Skanska, says it's the first time the company has used so much prefabrication on a single project. The company built an onsite fabrication shop and secured a warehouse across town. At its peak, the offsite shop had 120 workers staffing three assembly lines that were constructing up to 90 racks simultaneously. Austin says the shop has framers, plumbers, pipe fitters, electricians, insulators, welders and HVAC specialists working side by side in a manufacturing-type environment. "It was an evolving process, and there was a lot of synergy among the trades to figure out the process and order [of assembly]. Most were not shop-trained, but they started to like it," Austin says.
Skanska also constructed headwall units and 500 bathroom pods that included rough framing and drywall, with all in-wall services installed. Pod installations were sequenced with the enclosure schedule to maintain the required openings in each room entrance. "We had a schedule so that as each room was ready to receive, we placed the pods and went down the corridors," Austin says.
New Orleans-based MEP contractor MCC is responsible for building 700 of the racks for four of the five buildings. Michael Cooper, MCC project executive, says prefabrication allows greater quality control and consistency by having fewer people work on the pods in a controlled environment. Racks in the shop sit just 18 in. off the ground, allowing workers to gain access to the top and sides of work areas that would not be accessible if they were doing it in the field. "You're not dealing with pieces and parts that are 15 feet in the air," Cooper says. "As long as you are planning ahead and doing things in the right order, you don't get any complaints from the field."
Racks are transported into the corridors one at a time, then raised in place by four crew members using duct jacks. While traditional construction might have 20 different trades working simultaneously with ladders down the corridor, this technique requires just a few workers in a clean wide-open space. "You go down the corridor and see just [a few guys and] one ladder," says Skanska project executive Jim Clemmensen. "There aren't people tripping over each other. It dramatically improves safety."
Austin says because of the heavy use of prefabrication, building information modeling (BIM) was employed extensively to ensure quality and avoid field problems. Except for structural and architectural systems, crews remodeled all building systems to meet prefabrication needs. He says the modeling team digitally coordinated 1.6 million sq ft of building space in 16 months.
Although designs by the joint venture of NBBJ, Seattle, and Blitch Knevel Architects, New Orleans, were not created with a specific prefabrication strategy in mind, the design is flexible enough to accommodate it, says Mackenzie Skene, an NBBJ partner. The firm builds prefabrication into much of its basic design to cut waste and boost quality and safety.
For a project like this, speed and efficiency were critical. "You can work on two [jobs] simultaneously and then plug them in when the building is ready," Skene says. "It's a tremendous opportunity to get a jump on those things."
It's no easy task to manage a project with 1,500 workers, 20,000 schedule activities and 515 bid packages. Skanska currently has 82 employees from its Georgia, North Carolina and Florida offices on site managing subcontractors. Each of the five buildings has its own superintendents and project management team, essentially acting as stand-alone projects. Easterwood oversees building superintendents who manage their own schedules, quality control and safety.
"They manage their buildings as if [each] was a separate project," Easterwood says. "I manage them and spend my days going where the fires are. I don't plan a single day because every day is different."
Clemmensen says one of the job's first challenges was procuring work on such a large project. State officials set no hard requirements but wanted Skanska to ensure the project would use as many local contractors and as much local labor as possible, he says. To accomplish that, state officials divided the bid packages into as many small pieces as possible. In many cases, bids for the same services were split up between buildings. In addition to the pressure of dealing with so many contracts, Skanska also had a goal of procuring the job in only 120 days.
"Just to go through that process for so many packages in such a short period of time, we had over 40 people working on it," says Clemmensen. "It was a huge effort."
In such a large project with so many moving prefabricated parts, Austin says technology has been critical to increase efficiency and maintain quality control. Skanska is using more than a dozen digital resource centers—steel pods with high-powered computers and large monitors—that allow superintendents to access all of the latest designs and other information. The centralized technology approach eliminates the need for paper and human exertion to find needed project detail.
When completed, the University Medical Center will be one of the largest hospital campuses of its kind in the country. Facilities include a 560,000-sq-ft hospital with 424 beds; a 747,000-sq-ft diagnostics and treatment center; a 255,000-sq-ft ambulatory care building; and a 546,000-sq-ft parking garage for 1,400 cars.
The facilities are also designed to be resilient during storms. UMC is the replacement for the Medical Center of Louisiana at New Orleans, which closed after sustaining serious flood damage during Hurricane Katrina in 2005.
A sister state-run institution, Charity Hospital, suffered severe flood damage during the storm, was forced to evacuate patients and never reopened its doors. City and state officials say UMC will return much needed medical services to New Orleans and help propel the region to the forefront of medical technology.
When completed, UMC will be the only Level One trauma center in southeast Louisiana, so keeping it functional during future disasters will be essential. All mission-critical hospital facilities are located at least 21 ft above base flood elevation.
Less critical public and office spaces are placed at ground level. Technology and emergency power can continue to operate for up to a week after a Category 3 storm, according to NBBJ.
Easterwood says he has been very impressed with the quality of the work force in New Orleans. "We are restoring health care to New Orleans," he says. "The workers are excited to be here, and you can see it's an important thing for them and their community."