New Grand Avenue bridge infrastructure damaged in collapse
August 16, 2017
What was a twisted crumble of steel bridge girders from a section of the old Grand Avenue Bridge that collapsed during demolition work Tuesday night was more like a neat mess waiting to be hauled off the following morning.
The unexpected collapse of a full 210-foot span of the bridge crossing Seventh Street and the Union Pacific Railroad tracks did cause some damage to two columns already in place for the new bridge, a project official said Wednesday.
That will likely add to the cost of the $126 million project and could cause some delays, Dave Eller, regional transportation director for the Colorado Department of Transportation, said during a telephone conference with reporters.
On Wednesday, crews were busy removing the estimated 16 tons of steel that fell to the street and across the railroad tracks. The girders were being cut into sections to be taken away.
"Contractors were following the approved, very precise safety plan when this happened," Eller said. "There were no injuries, there was no private property damage and there was no damage to the railroad tracks."
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The Union Pacific said it experienced minor delays right after the incident, but the tracks were quickly cleared and inspected, and operations resumed around 11 p.m. Tuesday, UP spokesperson Raquel Espinoza said. The east- and west-bound Amtrak California Zephyr also were running on schedule Wednesday.
Eller confirmed that exposed rebar was severely damaged on two of the columns that will eventually support the piers on the south side of the Colorado River for the new bridge.
"We will have to assess that, and hopefully the damage is determined to be minor so that we can mitigate it and keep the project on schedule," Eller said.
None of the debris from the collapsed section ended up in the Colorado River, which is located farther to the north, he said.
The collapse occurred as workers were trying to pull two of the attached girders away from a pier situated between the railroad tracks and the Colorado River.
Eller explained that the bridge spans are made up of six girders attached in three separate sections. The plan was to remove two girders at a time and pull them to the road surface so they could be cut into smaller pieces.
When crews began to pull on the first girder section, the 64-year-old support pier twisted and gave out, and all six girders came down at once, he said.
"You plan the deconstruction process as best you can, but events like this are not unusual or unexpected when you are taking down large, old structures like the bridge," said Tom Newland, public information manager for the project.
Officials said the remainder of the old bridge structure over Interstate 70 and the river will continue to be assessed, but it does not appear to be compromised.
Eller said the section that collapsed was already detached from the remainder of the structure, so there was no jarring effect that would have damaged the spans still in place farther to the north.
Seven shorter spans of girders will be removed once engineers are confident that the demolition work can proceed, he said.
Because those spans are located over the river and I-70, a "much different" technique will be used, he explained.
"Our crews will be removing those girders one at a time using a crane from above," he said. "We are confident in using this technique, but we are re-evaluating the demo plan and are making sure we don't have any compromised piers out there."
Nighttime I-70 closures are in place when bridge demolition work is being done overhead. During those times, traffic is diverted onto the Sixth Street detour route.
At this point, officials said the estimated 10- to 14-day bridge demolition phase of the Grand Avenue Bridge project remains on schedule.
"It's a question of how much this will delay the project, and what we can do to catch up," Newland said. "We definitely probably lost one day on the deconstruction schedule."
Meanwhile, the usual evening traffic backups on the bridge detour route coming into Glenwood Springs from the south began around 4 p.m. Wednesday, when motorists and traffic control crews were bracing for another evening of congestion and long delays getting through town.
Morning backups along eastbound I-70 coming into the bridge detour route at exit 114 were reportedly not as long as they were Monday and Tuesday, Newland said.
"I noticed a big increase in people coming across the pedestrian bridge after getting off the bus about 7:30, so I think maybe more people are trying that," Newland said.
I-70 traffic coming into Glenwood in the morning, and the reverse commute back home in the evening have resulted in full gridlock at times during the first week that the detour has been in effect.
Project officials still hope to see a 35 percent reduction in usual traffic during the 95-day detour. To help accomplish that, a combination of free RFTA bus service between Parachute and Glenwood Springs, free in-town shuttles, permitted employee van pools, and encouraging people to walk, bike and carpool as much as possible are being employed.
One motorist stuck in the backup south of Glenwood Wednesday afternoon told the Glenwood Springs Post Independent that some people were getting out of cars on the passenger side and walking the rest of the way into town faster than the traffic was moving.