Egregious errors cited by federal investigators in the May 15, 2004, collapse of a girder that killed a family of three are a potent reminder to the Colorado Department of Transportation to make absolutely sure its staff and contractors follow new procedures intended to avoid such tragedies in the future.
Documents from the National Transportation Safety Board investigation of the incident showed several motorists, including a senior CDOT bridge-design engineer, saw the jury-rigged girder twisted out of position about an hour before it fell from a C-470 overpass onto Interstate 70.
The beam struck a Dodge Durango, instantly killing William Post, his pregnant wife, Anita, and their 2-year-old daughter, Koby Anne.
The engineer didn’t know whom to telephone. Another motorist who spotted the girder did call 911 to report a sagging I-beam, but a dispatcher told CDOT road crews there was a “hanging sign” at the interchange. The crews didn’t find any damaged signs and missed the distorted 40-ton steel girder.
Bad weather, the lack of a specific type of wrench and an error in assembling the girder delayed the project and contributed to the tragic accident.
The contractor temporarily braced the girder to the deck of the C-470 overpass on May 11, but bad weather prevented completing the job the next day. Crews didn’t have time to install a second girder, which, according to several experts, must be done for stability.
Workers temporarily fastened steel angle braces to the bridge deck, but the bolts weren’t embedded deeply enough, according to the NTSB documents.
New regulations require contractors to submit girder-erection plans including details on temporary supports, and a licensed professional engineer must sign off on the plan and each phase of girder installation before vehicles or pedestrians are permitted beneath the structure. Both the contractor and CDOT construction personnel must do daily inspections.
These are wise precautions, but unless they’re followed and implemented rigorously, they won’t be truly effective. Equally important, CDOT must make sure to check out and act on reports of trouble from the public. Lives depend on a prompt response.
