After 56 years of service, old bridge demolished at Fillmore/I-25
There's the new diverging diamond interchange (DDI), unveiled in late March, in which traffic switches sides at either end of the two new Fillmore bridges.
And the new southbound off-ramp and northbound on-ramp are becoming available to motorists (the latter scheduled to open this week). When the interchange was first built in 1960, the off-ramp was 700 feet long; now it's 1,200. The on-ramp was 400 feet; now it's 1,300. Less distance was needed in the earlier era because there was far less traffic, according to spokesperson Ted Tjerandsen of Wilson and Company, a project consultant to the Colorado Department of Transportation (CDOT).
Bridge drivers not fully engrossed by these upgrades may also have noticed April 4 that a 28-foot-wide, black asphalt segment no longer existed between the two bridges.
That missing expanse was the old Fillmore bridge. It was removed during three overnight operations (March 28 and 29 and April 3), during which I-25 was closed in both directions.
The demolition of the old bridge, at least the portion above the interstate traffic lanes, was completed in the early morning
The demo was carried out by Backhoe Services, a subcontractor to CDOT's project contractor, SEMA Construction. The Commerce City company deployed one and sometimes two multi-ton track excavators with breaker attachments, either working from the new, adjacent bridges or between them, on the floor of the interstate. First to go was the old bridge deck, consisting of asphalt over concrete and rebar. The girders below the concrete came down last, the night of April 3. All of the rebar and concrete is recycled, Tjerandsen pointed out.
Because of the juxtaposition of the two new bridges, the demo work was described as unusual and somewhat tricky. “Normally, we only have one new bridge next to an old one,” commented Backhoe Services owner David Ramsdale in an interview beforehand. “But here we have this 28-foot bridge sandwiched between the new bridges. So the risk factor goes up.”
Tjerandsen described the demo as “more surgical” than normal because “you don't want to damage the new structures.”
The three-night effort amounted to the second (and final) stage of the old bridge's demise. The first stage was last fall, when Backhoe Services - in keeping with a CDOT-approved plan - sheared off and then knocked down a 17-foot width along the north side of the old bridge. This part had been added in the 1970s, according to CDOT information, making its removal less problematic from a structural standpoint.
Removing that part provided space to build the new north bridge. While this task went on over the winter, motorists used the 28-foot-wide old-bridge remainder to carry the westbound traffic lanes.
This remainder was no longer needed after the north bridge was deemed traffic- ready at the end of March.
Now, with the main demolition work out of the way, SEMA crews will start focusing on installing permanent concrete islands for the DDI on the new bridges, Tjerandsen said. Until that work is compete, the DDI configuration will continue to be marked temporarily with the aid of 400 orange barrels and 200 traffic cones, he said.
Westside Pioneer article