Glenwood Springs weighing options for new 27th Street bridge
Close on the heels of the new Grand Avenue highway bridge completion in 2018, Glenwood Springs will be looking to replace another river span that has been given a low deficiency rating by federal bridge inspectors.
City officials this week unveiled three design options for the 27th Street, or “Sunlight” bridge as it’s commonly known, that crosses the Roaring Fork River between Midland Avenue and South Grand Avenue.
Completion of the bridge design and environmental review process to replace the bridge is anticipated next year. The city has put aside $1.2 million to fund the project.
Of that, $620,828 comes from the Federal Highway Administration off-system bridge funding, but more money will be needed to construct the new bridge, according to city officials.
Three bridge alignment and design options were explained at an open house Wednesday night. Formal comments are being accepted by the city through today.
All three bridge alignments being considered assume the construction of South Bridge, located near the municipal airport, to ease traffic congestion and allow another outlet to Colorado 82.
All three options also envision a separate pedestrian bridge downstream from the vehicle bridge.
Two design options envision a roundabout at 27th and South Grand. One would follow the existing alignment, so the new bridge would be built offline and slid into place after the old bridge is demolished, resulting in about a week-long closure.
“This option is a medium cost option,” according to a city description of the option. “This would be a two-lane bridge, constructed completely off line to the south.”
The other roundabout option would follow an alignment curving to the south. It would cost the least of the three options.
“Construction of this bridge would include a two-lane curved alignment to the south with a roundabout … Two lanes of traffic would be open most of the construction duration, with short night time closures of one lane during delivery of girders.”
Both of the roundabout options could be completed in a single construction season.
The most expensive of the three options would cover two construction seasons. It would involve a three-lane, curved alignment to the north of the existing bridge and a signalized intersection with a dedicated turn lane at 27th and South Grand.
“Two lanes of traffic would be open most of the time during the construction duration, with short night time closures during delivery of girders,” according to the city description.
Two lanes on the north side of the bridge would be constructed one season, and traffic moved to the new bridge. The old bridge would be demolished and the last lane constructed in the next season.
The 27th Street Bridge was originally constructed as a joint project by Garfield County and the city in 1968 and was officially in service in 1969.
The original bridge had a steel deck that was replaced with concrete decking in 2001 in order to extend the bridge lifespan a minimum of 10 years. At that time, the bridge closed for approximately nine months while it was re-decked.
During the winter of 2010-11, the Army Corp of Engineers completed work to prevent scouring from the river beneath the bridge pillars. The bridge is still considered a “scour vulnerable bridge.” Bridge inspections in 2011, 2013, and 2015 determined that the bridge is “functionally obsolete,” the same designation that was given the Grand Avenue bridge before state transportation officials decided to replace it.
Construction of the new 27th Street bridge could start by late summer/fall of 2018, depending on funding availability.
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