Take Me Out to the Ball Park
By K. Robert Wendel

In an age of mega stadiums, the Phoenix Municipal Baseball Park stands out as an intimate ballpark that recreates the excitement and familiarity of baseball, before the megastars and huge salaries.

The stadium is also known for its unique accordion roof structure.

So when the city of Phoenix decided to remodel the park, which was constructed in 1962, much of the discussion revolved around the park's signature roof. Although initial programming called for its removal, the building team renovating the stadium was convinced the roof could be saved and integrated into the renovated park.

"The programming study by the prior firm essentially removed the roof," said Jason Boyer, a senior associate with project architect Gould Evans & Associates of Phoenix.
"We felt the roof's character is essential to the stadium. It's one of the more iconic elements of architecture in Phoenix and we wanted to save that."

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General contractor Barton Malow Co. of Phoenix was then faced with the all-too-common task of putting 10 lbs. of stuff into a 5-lb. bag. The $8 million renovation called for a complete upgrade on the press box; more office space for the Oakland A's, who use the field as home during spring training; and a complete rework of the park's landscaping and hardscaping.

"It's going to be an all new ball park," said Barton Malow, project manager Tom Harrison. "We have done a lot of things to improve the fan and player experience and people are really going to notice the difference."

To preserve the roof, other means were needed to supply the renovated press box with electrical and mechanical upgrades to meet the media demands.

Contractors removed much of the mortared rock wall to create a new mechanical and electrical space underneath the existing press box. Engineers then designed a mechanical system utilizing a plenum, along with variable air volume boxes and a split-system air handler.

Associated Engineering Inc. of Phoenix extensively upgraded the electrical and data capabilities to handle the demands of the high-tech media.

"It was tight underneath the press box, so we put in a plenum underneath the press box, rather than ducting the return air back," said Peter Kunka of Phoenix-based Kunka Engineering Inc. "The project has so many seemingly minor things involved, but the whole thing comes together to give a better experience at the ball park."

Crews from Ace Asphalt of Phoenix faced a tight site when excavating for a new elevator shaft near the press box. With no room for shoring and a host of sewer and optical lines, workers had to lay back >> the slope to a one-to-one ratio, especially after running into structural concrete 18 ft. below grade.

"It was a touchy situation but we got through it okay," said Ace Asphalt senior project manager Jim Troncale. "We used the existing building structure as one shore wall, but we had to lay the two sides back at one to one. There wasn't a whole lot of room."

A second floor was added to the Oakland A's office, which essentially doubled the team's floor space and provides a better view of the field.

The original office featured existing precast concrete double Ts, so engineers believed the building could take the weight of another story. But in the end, steel columns were installed to the basement to support the extra floor.

A metal pan deck with a 2.5-in. concrete topping provided the floor for the next level, with the walls constructed of load-bearing masonry. Centimark Roofing of Phoenix capped off the new office, as well as re-roofing the accordion roof.

"Originally, the roof was an amalgamation of paint and goo and everything in the world," said Centimark Roofing senior project manager Rick Fennemore. "It had been leaking for some time. The roof conditions were really conducive to spray foam, given the uneven surface and the odd angles. It would have been too much work trying to make the relief cuts if we would have used sheet roofing."

As part of the overall project, Barton Malow also constructed a new maintenance shed, and the field's lighting was upgraded and improved. Crews added two new entrances, along with aboutsome 4,000-cu. yds. of new hardscape featuring decorative and colored concrete.

"There's a lot of really decorative concrete," said Dan Gonzales of RBG Concrete of Phoenix said. "The hardscape was difficult because his firm had to make sure the banding came out, but it was an exciting experience."