A rendering shows the running track suspended above workout spaces and basketball courts. The new facility was designed for ample daylighting and visibility.
Image courtesy Cushing Terrell

Unifying Programs

The Y serves more than 67,000 members in the valley through hundreds of programs and services, with 43,565 youth accessing its programs last year, Ellis says. It is also the largest provider of child care in the state of Idaho with 1,200 staff members and 1,000 volunteers supporting this work every day.

A study conducted in 2017 to evaluate upgrading the building determined the cost to be just over $20 million without adding any new space. “We knew this was not the best use of our donor-invested funding, so we embarked on new construction,” Ellis says.

The joint venture team of Boise-based McAlvain Construction and Andersen Construction holds the CM/GC contract to deliver the project. The new YMCA is designed by Florida-based GRO Development—which is also the national design partner for the YMCA—alongside Cushing Terrell architects of Billings, Mont. The team had to manage challenges ranging from significant changes to the site plan, being judicious with the nonprofit’s tight budget and a constrained site in a busy section of downtown close to the city’s high school.

A limited site meant closing a street for the day so long-span trusses could be delivered, assembled and then lifted into place.
Image courtesy McAlvain Construction

Amy Lindgren, architect-of-record at Cushing Terrell, says that early in project development the firm worked closely with GRO Development. “We worked back and forth with them on early concepts. Then we did significant modification of the initial designs because we had to cut square footage and make some changes to fit the budget and then work with the city on design reviews,” Lindgren adds.

Key features include two swimming pool—an Olympic-size lap pool and a recreational pool area—plus a gym with weight lifting equipment, basketball courts and a variety of multipurpose spaces. In addition to the CapEd Credit Union branch office and the St. Luke’s health center at the new YMCA, Lindgren says the designers and owner wanted to find a unifying feature for the many varied spaces, and this came in the form of an open staircase that reaches up from the basement to the fifth floor of the building.

“It is a centralizing feature that can direct everyone to different spaces. We had to work with the city to get a code alternate so we could have it open all the way up, but it’s a nice feature and a good way to direct people,” she says.

The tight site left no room for the contractor’s crane. The issue was solved by pouring a footing on the subgrade level and erecting the crane through the middle of the structure.
Image courtesy McAlvain Construction

Managing Challenges

Just like the current facility, the new building will be connected to Boise’s geothermal heating system. Operating for more than 100 years and with around 20 miles of pipe throughout the city, this system is the largest in the U.S.

Thermal springs at the east edge of the city produce water at 177°F, which is then pumped to around 100 buildings, including the city hall, the state capitol and even residences. With the use of heat pumps, the water can be used for heating and cooling.

“We bring the water in at around 170 degrees and dump about 50 [degrees of heat] into heating the pool and the building’s hot water system,” says Tim Johnson, a mechanical engineer for Cushing Terrell, who designed the building’s HVAC system. “I really wanted to use it for space heating as well, but the cost of piping [was too high]. This was back when the new tariffs started. We looked at a few different options and ended up with a VAV (variable air volume) system for the building.”

Johnson says the mechanical team found additional cost savings with the dehumidifying system for the pool area.

“We went with a mechanical system, and the waste heat it generates is sent into the hot water system, so really, anything that evaporates off the pool is sent back as reheat,” he says. “It helps reduce the amount of geothermal water they will have to pay for.”

Accommodating the varied uses of the facility required extra consideration for the structural engineers as well, says Chad Rosenberger, with Boise-based Axiom engineering.

The space for the pools needed to be column free, but the floor above the space is one of the multipurpose rooms.

“We used trusses for that longer span [about 75 feet], but we know we were going to have to deal with vibration from that [multipurpose room],” he says.

The trusses over the pool were 10 ft deep, while those in other portions of the building were 5 ft deep.

“We also added 2 more inches of concrete on the floor pan so it is 8 inches thick, but everywhere else is 6 [inches],” Rosenberger says.

The long-span trusses and a constricted site were challenges for the building team. Austin Crann, senior project manager for McAlvain Construction, explains that the long trusses were each made in two pieces, with four sections total, and delivered to the site. The street was closed while the team assembled the trusses and then flew them into place with the tower crane.

Rather than pouring concrete, crews used piles, shoring and shotcrete on the subgrade level of the facility to save time and reduce costs.
Image courtesy McAlvain Construction

Crann says placing the crane was tricky due to the limited laydown space. “We ended up pouring a footing for the crane directly under and directly in the middle of the building. Then we assembled the crane and built the building around it,” he says. “The location of the tower crane is now the core staircase [so] when it was time, we pulled the crane out of the top of the building section by section and then we dropped the structural staircase down and closed up the roof.”

The joint venture team conducted extensive preconstruction value engineering with the YMCA team and architects. Crann says utilizing shotcrete on the subgrade level enabled savings of both time and money, noting that it is a new approach in the Boise area.

“We drove 30-foot steel piles about 15 feet into the ground, so we had 15 feet exposed above grade. Then we came in with shoring and used those as a one-sided form, built our cages on those boards and sprayed shotcrete,” he says. “From a structural standpoint it’s just as strong, and we did it in half the time it would have taken to do traditional two-sided vertical forms.”

The joint venture team worked to secure materials as early as possible, and this helped to avoid some of the price escalation that occurred in the last two years. “The other issue was getting things on time and in the right sequence,” Crann says. “We don’t have room on site for storage or for trucks to wait, so [materials] arrive right when we need them.”

The project is currently on schedule for an October grand opening.