RANCHO MIRAGE, Calif.—Placement of a mat slab foundation designed by Degenkolb Engineers, the structural engineering firm for the new Walter and Leonore Annenberg Pavilion operated by Eisenhower Medical Center, represents the largest concrete pour in Coachella Valley history. The operation began at 7:00 p.m., July 20, and continued until approximately 10:00 a.m. the following day.

According to Degenkolb, compliance with precise specifications required strict coordination among 600 truckloads of concrete and 20 onsite inspectors to ensure complete structural integrity of the new pavilion.

Awarded the contract in February 2004, the design team—led by Moon Mayors Architects and supported by Degenkolb Engineers in tandem with Turner Construction—sought to bring this new 250,000 square foot, four-story, special concentric-braced frame building to life. Poor soil conditions necessitated use of a mat foundation system to comply with state requirements for seismic safety mandated by the Office of Statewide Health Planning and Development (OSHPD). In accordance with California SB-1953, which requires all acute care hospitals in the state to evaluate and report on the structural and nonstructural safety of all their hospital buildings, the new Annenberg Pavilion will house services that are being relocated or expanded from an existing structure that will be decommissioned. The new facility will prevent Eisenhower Medical Center from closing following any sizeable seismic activity and will help move them toward compliance with SB-1953.
The mat foundation system functions as a cost-effective solution to the poor soil conditions at the site, according to Degenkolb. The braced-frame lateral system was positioned in the building to minimize the impact on occupant flow and to provide a robust response to expected seismic demands. Anchor bolts measuring 3 inches in diameter and 7 feet long were placed to bolt the steel structure to the 23 million-pound, concrete foundation.