Northwestern University in Evanston, Ill., is located on the western edge of Lake Michigan. Visually, the shoreline is the perfect spot for the new Ryan Fieldhouse & Walter Athletics Center, offering students and visitors panoramic views of the Great Lake. However, exposure to waves at the waterside location posed a fundamental problem for the structure.
This challenge led architects to using precast concrete for the water-facing wall, says Patrick Brawley at SmithGroup JJR, the engineer of record. “The precast concrete wall needed to account for coastal wave loads and ice-rubble mounds, all while providing an aesthetic that embraced the beach and sand dune environment,” he explains.
With the unique setting, tight project sequence, and regulations that limit construction activities adjacent to the lake, precast concrete was the ideal solution, says Tom Heraty, vice president of sales and engineering for Utility Concrete Products. The material must be strong enough to stop damage to the building’s foundation from the horizontal force of waves, and the structure has to shield pedestrians passing along the front of the building on a multi-use path. “This wall protects the crown jewel of Northwestern’s athletic facilities against constant waves battering it for life,” Heraty says. “No compromises in durability were acceptable.”
The project’s design mirrors the naturally curved layout of the beach, with a rolled face and varying elevations in height. To protect the structures against the crashing waves and freeze-thaw environment, precise placement of epoxy reinforcement, embedded stainless steel angles, and hot-dipped galvanized/epoxy connectors was critical.
To ensure durability and a consistent surface for the structure, the architect required no mechanical connections or lifting points in the lakeside exposure wall. UCP addressed this challenge by using hidden splice sleeves on the beach-side erection. The sleeve is grouted through polyvinyl chloride ports that extend from the sleeve to the exterior face of the precast concrete wall.
The use of precast concrete also helped to keep the job site accessible because fabrication occurred off site and deliveries only took place when segments were ready to be installed. “The constraints associated with typical cast-in-place construction were alleviated, which allowed for an increase in site access and productivity,” Brawley says.
The precast concrete wall is more than just a practical structure for this campus, Brawley adds. “The owners and community will see an acid-etched, integrally colored, extremely functional sculpture along the lakefront that artfully connects the beach and dune environment.”