Tight tolerances between floors containing the Soldier Field's 133 skyboxes meant that precision and coordination were required to make systems fit within the confined space.

"Space was at a premium above the ceilings of the suites for MEP systems," said Mark Simonides, project executive for TBMK, the joint venture of Turner Construction Co., Barton Malow Co. and Kenny Construction Co. serving as general contractor. "It took a lot of cooperation between the designers, our joint venture and the subcontractors to fit the systems in above the ceilings. It wasn't that different from a typical office building."

Beam Penetrations Cause Woes

Because designers placed a premium on putting fans as close to the action as possible, there wasn't a lot of extra room between the floors holding skyboxes. Suites were given little headroom, said Ben Wood, design principal with the LW+Z Joint Venture. (The project is a joint venture of two architectural firms: Chicago-based Lohan Caprile Goettsch Associates, with primary responsibility for the master plan and North Burnham Park project, and Boston-based Wood & Zapata, with primary responsibility for the architectural design of the Soldier Field stadium.)

"We were dealing with a lot of close tolerances and beam penetrations," he said. "Beam penetrations were the biggest headaches for everyone ... The engineers had to make sure the beam penetrations didn't compromise the structural integrity [of the] beams. And, the HVAC team had to work very accurately to place the ductwork.

"In a stadium where everything is built to close tolerances, you have to really draw where every pipe and every conduit goes. You even have to figure out where all the electrical lines will go, because you don't have the benefit of a lot of additional space. You're trying to keep those suites and club lounges, as well as every other seat, as close to the field as possible."

The tight floor-to-floor dimensions eliminated the majority of the interstitial space typically used to run ductwork, plumbing and pipe, added Tony Montalto, associate and lead site architect for the LW+Z Joint Venture. And while beam penetrations were the only option for running many horizontal pipes, holes couldn't be cut just anywhere.

"Dimensionally and structurally, you're limited to certain areas of the beam where you can pop a hole through it," he said. "It forces all the ductwork and piping, all the MEP through very specific zones."

The pursuit of precision was all the more crucial given that there is no room for error in stadiums, Wood said. There have been newly constructed stadiums that promised unblemished sight lines but left some fans with views of the field marred by obstructions.

"You can't say, 'Whoops, you're sitting behind a column' or 'The overhang's too low,'" he said.
"You can't spend $620 million on a stadium and then ask a couple thousand fans to sit in bad seats."

Timetable Affects MEP

Another MEP issue was the compressed 20-month timetable contractors had to complete the project, Montalto noted.

The schedule necessitated the use of multiple trades working in the same areas at the same times. "A sequential process turns into an overlaying process," he said. "You have to be far more precise, far quicker. You can't wait for one system to be complete to realize the limitations of the possibilities with the remaining space."

About 80 percent of the stadium's plumbing is exposed to the fearsome winter winds blowing off Lake Michigan, Wood said. Because most of the stadium is an outdoor structure, the vast majority of the more than 60,000 fans in attendance will be walking along unheated concourses, using unheated bathrooms and standing in unheated concession areas, he said.

"You're running supply lines and waste lines, and all the utilities that are serving those bathrooms and concession areas are subject to the weather," Wood explained. "So you have to protect all that in the winter time. Engineers have to provide a lot of insulation and care in how these pipes are treated."

The same insulation efforts were required for the exterior pipes used to drain water from the approximately 400,000 sq. ft. of exposed concrete in the seating bowl, he added.

Has Twin Scoreboards

Other MEP issues revolved around the twin scoreboards and the playing field itself, said Alice Hoffman, president of Hoffman Management Partners LLC, the Chicago-based developer's representative for the Chicago Bears.

The scoreboards came in packages from the manufacturer, Daktronics, and the individual panels were assembled and erected on substructure.

"It took only three days to get each one up," she said. "During the day, they're as bright as a drive-in movie is by night. It's that [high] quality a picture. Very, very bright; very, very big."

The stadium doesn't have an onsite plant, Hoffman said. Instead, three feeds come in from the utility ComEd, which added additional power to the site in 2001. If a power failure occurs, the stadium's large emergency generator will power emergency lights and systems.

MEP came into play in the field's heated playing surface, Hoffman added.

"In order to trick the grass into staying green through January, we heat the roots to 50 degrees [Fahrenheit] by pumping in heated glycol underneath the root zone in pipes," she said. "They had a field heating system at the old stadium, but it had to be completely replaced because we drove all our cranes out there and demolished the existing field. It would have obviously crushed all the pipes."

In addition to the pipes pumping heated glycol, two other piping systems are hidden beneath the grass: one for drainage and another for sprinkling. "It's a pretty complicated system," Hoffman added.

Indeed, intricacy defines the project.

"We had this landmark building to work around," Wood said. "We had to save the colonnades.

That had it's own geometry, and within that we had to place the new geometry. I can't imagine a more complex building."