Palmdale, Calif., is situated in the northwest corner of Los Angeles County, and soon will be home to a more than 200-bed hospital. Because it is in a seismically active region—the hospital is just a mile and a half from the San Andreas fault—its structural elements are both massive and heavily reinforced.
Groundbreaking for the Palmdale Regional Medical Center occurred in June 2005. The $100 million facility is being built as a for-profit by Universal Health Services. The full-service hospital will feature a 35-bed emergency room and is expected to be completed later this year.
The five-story structure has a 140,000-square-foot footprint. Normal gravity columns—190 on the ground level and approximately 140 each on the levels above—tie the floors and vertical structure together. The columns include 250,000 pounds of reinforcement and another 1.3 million pounds in the decks.
The hospital has 16 shear walls, most of which are 14 to 20 inches thick, that reach up to the fifth floor. These shear walls contain another 200,000 pounds of reinforcing steel and have boundary columns at each end.
The building is supported by 1176 heavily reinforced concrete piers, each 30 inches in diameter and 60 feet deep. The pile caps over the piers are 5 feet thick and have two mats of #11 rebar. The total rebar in the piers and pile caps is 6½ million pounds. Of the two dozen pile caps, most are in the 500- to 600-cubic-yard range. However, three of the larger ones ranged from 1800 to 2000 cubic yards. The largest, which was placed in January, required more than 2400 cubic yards.
According to Bob Cornelison, ready-mix manager for the Palmdale Plant of Service Rock Products, which supplied the concrete, the pile cap pours were among the largest in which the company has participated.
Being in the high desert, on the southwest corner of the Mojave Desert, crews had to contend with cold weather in the winter months. Temperatures were in the single digits the first weekend in January 2007 when the final and largest pile cap was poured. That placement began at 1 a.m. on a Saturday and was completed in nine hours.
“There were a lot of icicles on our trucks,” Cornelison says, “but everything went pretty smoothly.”
- Owner/developer: Universal Health Services, King of Prussia, Pa.
- General contractor: Layton Construction Company, Sandy, Utah
- Concrete contractor: Conco, Concord, Calif.
- Concrete producer: Service Rock Products, Palmdale, Calif.