Only hours before contractors were to lift a 52-ton assembly of bridge girders at C-470 and Interstate 70 on Monday night, state officials canceled the operation, saying a steel plate on which the girders would rest did not meet state specifications.
The planned installation is at the site of a girder collapse nearly 15 months ago that killed a family of three in a passing sport utility vehicle.
Officials of the Colorado Department of Transportation have been planning the new installation of girders for more than a year.
But until Monday, apparently no one from CDOT or its contractors checked the steel bearing plates attached to the concrete pier in the median of I-70.
“We’re not going to proceed until we’re absolutely certain the materials are in perfect condition and the installation process is as safe as it can possibly be,” CDOT executive director Tom Norton said Monday evening.
He said it will take about a week to fabricate a new bearing plate for the girders, and the installation will be rescheduled at that point.
CDOT spokeswoman Stacey Stegman said one out of three steel plates on the concrete pier did not have the proper curvature to accept the weight of the girders.
“It’s good we discovered it now” and not following installation of the bridge beams, she said.
It was at the C-470/I-70 interchange on the morning of May 15, 2004, that a single 200-foot- long girder, installed three days earlier and braced only temporarily to the C-470 bridge deck, moved out of position and sagged to I-70 below, shearing off the top of the SUV.
The accident killed the vehicle’s occupants, William and Anita Post and their 2-year-old daughter, Koby Anne, of Evergreen.
Anita Post was pregnant with the couple’s second child.
In November, the state of Colorado and contractors involved agreed to pay their families $1.5 million, with no admission of liability.
Federal highway-safety officials still are investigating the accident, but suspicion has centered on inadequate bracing of the 6-foot-tall girder, which allowed the steel beam to roll out of position and fall to the highway below.
On Monday, CDOT engineers said a new arrangement of twin, parallel girders, with permanent braces between them, will be stable and have no chance of failure.
The braced beams “eliminate any possibility of rotation of the girders,” said Bill McDonnell, a CDOT engineer working on the bridge project.
In the May 2004 incident, a second, parallel girder was to have been installed shortly after the first, and with bracing, provide stability.
Yet because bad weather quickly set in, only one girder was up, and the remaining installation was delayed for days.
Shortly after the accident, some bridge experts said the single beam was “inherently unstable.”
Staff writer Jeffrey Leib can be reached at 303-820-1645 or jleib@denverpost.com.
