One construction worker died and seven others were injured from the collapse of a 100-ft-long section of falsework on a northern California bridge construction project Dec. 3. Officials decline to speculate on the cause, but say that a hydraulic jack slipped immediately before the 75-ft-tall falsework section collapsed.

The accident occurred on the Maxwell Bridge, a $40-million project in Napa that will replace an adjacent 1940s-era bridge spanning the Napa River. The project’s general contractor, C.C. Myers Inc. of Rancho Cordova, Calif., has completed about half of the westbound span of the 1,700-ft-long concrete segmental box girder bridge, which has been under construction since April and is scheduled for completion in late 2005. The completed section sustained no damage in the accident, says Barry Martin, a spokesman for the city of Napa’s transportation management plan.

Officials familiar with the investigation say a hydraulic jack slipped while workers were attempting to bring two bridge segments into alignment. When the jack slipped, a horizontal I-beam "shot out," says one official, causing the collapse of the 100-ft-long, 50-ft-wide section of the 400-ft to 500-ft-long steel and timber falsework. There were "no leading signs that this was going to happen," the official says.

Richard Christopher Stevens, a 20-year-old C.C. Myers employee working beneath the falsework, died in the collapse, and seven were injured, including employees of C.C. Myers; a subcontractor, Napa-based Bay Area Rebar; and a Caltrans inspector.
"We just don’t see a lot of accidents like this," says Dean Fryer, spokesman for the California Division of Occupational Safety and Health. "It’s not a common type of incident." A search of the agency’s database turned up no previous accidents on the project requiring a response from Cal-OSHA, Fryer says. The state investigation is likely to take several months, he says.