A Real Game-Changer

Northwestern University’s new 433,000 square foot athletic center and fieldhouse is shaping the campus and the student-athletes that use it in a positive way, and precast concrete is playing an ongoing role in its success

By Bridget McCrea

When Northwestern University decided to build an ultra-modern athletic facility on Lake Michigan, it knew it would have to come up with a solid plan for dealing with Mother Nature and the storm waves she likes to spin up from time to time.

Built right on the water’s edge in Evanston, Ill., the $270 million Ryan Fieldhouse and Walter Athletics Center project spans 433,000 square feet. Completed last year, the state-of-the-art facility is one of the premier sports centers in college athletics.

“The Walter Athletics Center has been an absolute game-changer for Northwestern student-athletes,” said Brian Baptiste, Northwestern’s deputy athletic director. “For the first time, core support services like academics, sports performance, athletic training, performance nutrition and professional development are under one roof, and integrated within the heart of Northwestern’s incomparable campus.”

Achieving that goal took some ingenuity on the part of project engineers, who had to come up with a way to buffer the waterfront facility, and the people who use it, from Lake Michigan’s waves.

To solve this fundamental challenge, Chicago-based SmithGroupJJR, engineer of record, used a precast concrete wall that not only shields the beautiful new facility from the elements, but also includes an aesthetic that matches the shoreline environment where it’s located.

Patrick Brawley, principal at SmithGroupJJR, said the wall needed to serve two purposes.

“We worked with the university and the architects to site the building and design a coastal wall that would enable construction of the facility and ensure that it wouldn’t be adversely impacted by the coast action that occurs when Mother Nature decides to let loose,” he said.

A trip to Texas

For the precast wall, Brawley’s team conducted various numerical and physical modeling tests to devise design scenarios. Early in the design phase, both filling in the lake and using offshore breakwaters were taken off the table.

“We were exploring alternative options – including moving the building back away from the shore, but there were still concerns about the wave actions and the fluctuation of the lake levels,” he said.

In search of a viable solution, the engineers conducted a metric survey of the lake and then took their data to Texas A&M University’s Offshore Technology Research Center, which operates a unique model testing basin that’s used for offshore technology, education, research and testing.

“It’s basically a large wave pool that we used to recreate the site for the new athletic center,” said Brawley, whose team used historical wave data obtained from lake buoy surveys to model certain storm events. It didn’t take long for engineers to realize that a wall barrier would be Northwestern’s best option. Without a wall, both the water and spray would be elevated into the air and would not only impact the structure, but also the pedestrians walking in and out of the building along the shoreline.

“We also looked at the climatic conditions and potential ice buildup and what these could do to the building,” Brawley said. “That started dictating the need for a curved wall to serve as a barrier between the lake and the center.”

As for the wall materials, the project design team explored its options before deciding on precast concrete.

“The level of design and finish we were looking for was hard to achieve with cast-in-place and there were also some regulatory constraints because the wall could only be implemented from its backside,” Brawley continued. “We weren’t allowed to be on the lake side of the wall during implementation because those were U.S. waters and not on private property; our permits didn’t allow us to stage work there.”

The engineers also considered plastic for the project, mainly due to its translucent qualities, but the team had concerns about its durability so that idea was scrapped as well.

In the end, precast concrete won for its durability, flexible design qualities, and ability to blend well with its surroundings by curving and undulating to match the shoreline where it’s located.

“We didn’t want the wall to just be a utilitarian piece,” Brawley said. “We wanted it to be integrated into the site, and precast enabled design flexibility. We didn’t just want standard concrete. We wanted it to blend in with and be responsive to the environment.”

Key project considerations

Using precast provided the most watertight solution on the wall’s backside, opening up the engineers’ options for anchoring the wall and proper securing of the structure from the back of the wall.

“We were able to reduce the use of mechanical fasteners and fill in the gaps on the lake-facing side of the wall,” Brawley said. “That was another unique aspect of the precast.”

Precast concrete’s durability also came into play during the material selection process. Knowing just how much force Lake Michigan can unleash during storms, both upward lift and potential torque were taken into consideration.

“We actually have more caissons supporting the weight-wall than there are caissons supporting the entire building, which is unique from a site standpoint,” he said.

Envisioning a wall with distinct curves that replicated the appearance of a wave, the project’s architects wanted a structure that was both durable and aesthetically pleasing. Consisting of 109 5-foot-wide segments, the precast wall was designed to stand at 20’ tall and taper at each end where it begins to flatten, similar to a wave.

According to Tom Heraty, vice president of sales and engineering at Utility Concrete Products in Morris, Ill., who produced the pieces for the project, the self-consolidating concrete mix design incorporated Scofield SG “Sand Buff” liquid integral color, which was altered to match a sample of existing building limestone. The segments were sandblasted by UCP’s team for a final product that achieved the architect’s desired appearance.

Other important considerations included the precise placement of epoxy-coated reinforcement, embedded stainless steel angles and hot-dipped galvanized/epoxy connectors within the high-strength concrete. Using UCP’s design, the contractor bolted down the wall at specific points and then continued with the expedited installation process, instead of using a bracing system and waiting for the grout in the sleeves to set up.

The location of the connection elements was critical and required very tight tolerances, but all the segments were placed with no fit issues.

Meeting creative and structural requirements

Designed with inward and outward radii, the wall includes two levels of wave breakers that catch, deflect and redirect the water as it hits the structure. The first level stops the waves from eroding the building’s foundation while the top level keeps pedestrians dry.

“When waves come up, they hit the wall, climb up it and then hit the horizontal lip,” Heraty said. “We also added a 20-foot-tall top portion that prevents splashing over the wall.”

Time was of the essence on the project, and precast made the tight timeline possible.

“The foundation for the building was in place, but in order for the other phases of the project to continue, the wall needed to go in within a certain period of time,” Heraty explained. “They wouldn’t have had time to cast-in-place on that schedule.”

The only challenge during construction was setting the first piece of precast, which was actually in the middle of the wall rather than the beginning or end.

“Once that was done, the pieces were set and ready to go,” said Brawley, who often recommends precast to other engineers for its ability to meet specification requirements. For example, on this project, designers had specific strength requirements that had to be incorporated, including those impacting the wall’s final shape and form.

“We reached that goal,” he added. “By selecting precast, we got a material that was flexible and fluid enough to respond to our creativity while also meeting the structural requirements.”

Asked how everything is going with the university’s new athletic center and field house, Baptiste said that just six months into its existence, the facility is already transforming student athletes’ lives. As proof that the wall is one of the most interesting aspects of the project, Northwestern Football Coach Pat Fitzgerald points it out every time he gives a tour of the facility.

“It has built a foundation for the world-class experience we aim to provide each of the more than 500 young men and women that represent Northwestern across 19 varsity teams,” he said. “Walter Athletics Center has established a new standard for student-athlete development in college athletics.”

Bridget McCrea is a freelance writer who covers manufacturing, industry and technology. She is a winner of the Florida Magazine Association’s Gold Award for best trade-technical feature statewide.