CO 90 Bedrock/Dolores River Bridge Replacement
About the Project
In August 2017, CDOT completed the construction of the new Dolores River bridge on Colorado Highway 90, about four miles east of Bedrock and 15 miles east of the Utah-Colorado state line.
Crews dismantled the old truss bridge and replaced it with a new pre-cast concrete structure. The new bridge will provide several improvements for the driving public including wider and higher clearance for oversized vehicles.
A SEMA crew started work in December 2016 and completed the project in mid-August 2017.
Project Facts
- Contractor: SEMA Construction
- Cost: $3.8 million
Background
In the fall 2014, a crack was discovered in a beam of the original steel through-truss bridge. The damage forced the closure of the old bridge. A temporary bridge was constructed to allow single-lane, alternating flow of traffic controlled by a light signal.
The Dolores River Bridge, a steel Pennsylvania through-truss bridge, was built in 1952. In 2002, the bridge was listed on the National Register of Historic Places for its architectural significance. The Dolores River Bridge is one of 10 remaining intact steel through-truss bridges statewide. Because of its historical significance, there is potential to have the old bridge relocated for use as a pedestrian/bike path structure.
Time Lapse
Bedrock Bridge has moved..so very carefully to provide the opportunity to be dismantled piece by piece, in hopes of finding a new home.
5/8/2017 - UPDATE:
River Closures Now Set to Start Tuesday, May 16 -- Look Out for “The Minion"
CDOT and SEMA Construction will begin lifting the large precast members for the new Bedrock Bridge over the Dolores River at Colorado Highway (CO) 90 on Tuesday, May 16. River users will encounter intermittent half hour river closures at this location just north of the Bedrock boat ramp, while large pieces of concrete are suspended over the river and positioned into place.
“This has been a very unique project!” said Andrea Meduna Bridge Project Engineer. “This past winter, when we started dismantling the old historic structure and then constructing the new bridge, we began to recognize that unusually significant snowfall in the high country would result in very favorable rafting conditions for our river friends. We truly appreciate the cooperation of the boating community as we continue our efforts to construct this new road bridge yet provide safe access to the river.”
May Activity:
- Monday, May 15: The buoys will be placed in the water.
- Tuesday, May 16 ― Friday, May 27: Periodic half hour river closures are anticipated.
- Saturday, May 20 ― Sunday, May 21: RIVER OPEN -- NO CLOSURES over the weekend. Please note buoys will remain in the river during the “open” condition.
- Memorial Weekend, Saturday, May 28 ― Monday, May 29: RIVER OPEN -- NO CLOSURES over the holiday weekend. Please note buoys may remain in the river during the “open” condition.
River User Impacts & River Closure Process:
- A flagger will be stationed at the Bedrock boat ramp to answer questions, give direction and inform boaters of the possible closure ahead.
- A large pre-warning yellow buoy (affectionately named “The Minion”) is in place on the river approximately 1,000 feet before the Bedrock boat ramp warning boaters of potential half hour closures.
- While waiting for the river to re-open, boaters can “park” or anchor boats, rafts, or kayaks to two white buoys (with blue stripes) using ropes attached to the buoys. These two buoys are located near the boat ramp. Or if possible, for smaller crafts, wait out the closure by catching an eddy.
- Be aware of a rope line of 7 orange buoys across the river indicating a closure, if the white buoys are missed, please grasp the orange buoy rope.
- Once crane operations are concluded and passage under the bridge construction is safe, the flagger will re-open the river (remove the orange buoy rope from across the river) and allow boaters to pass through the bridge construction zone safely.
Dolores River Bridge
CDOT Structure K-01-C
History Colorado/National Register Multiple Property Submission
Built in 1952, the Dolores River Bridge carried Colorado Highway (CO) 90 across the Dolores River east of the community of Bedrock in Montrose County. Located in a remote section of Southwest Colorado, CO 90 was one of the state's earliest highways—initially known as the Paradox Road and, later, State Primary Road No. 20.
This road extended west from Gunnison to Montrose, through Bedrock, where it crossed the Dolores River, and into Utah. In the 1920s, the section of this road from Montrose to the Utah state line was re-designated as CO 90.
The bridge was a late example of a steel, rigid-connected Pennsylvania through truss—a bridge type that derived its name from the Pennsylvania Railroad, which patented the design in 1875 for use by locomotives. The type was later adapted for vehicular traffic, but was not used commonly on Colorado's highways, where the single-panel Parker through truss was a more popular choice.
The steel truss members were fabricated by the Midwest Steel & Iron Works, a company founded in Denver in 1893 that continued to fabricate steel into the 1980s. The Colorado Department of Highways contracted Gardner Construction Company of Glenwood Springs, Colo., to build the bridge at a total cost of $73,688.54.
The Dolores River Bridge was 125 feet long and supported by concrete abutments and wingwalls, and it featured steel lattice guardrails. Its combined polygonal top chord and subdivided panels distinguishes it from other truss designs, including the Pratt, Whipple, Baltimore, and Parker. Its simple design made it easier to construct than these truss types.
In 2002, it was listed on the National Register of Historic Places as an important transportation-related resource and as intact example of a Colorado Highway Department truss design. It was the only Pennsylvania through truss bridge identified in CDOT's 2000-2002 statewide historic bridge inventory.
In September 2014, a crack was discovered in a vertical truss member, resulting in closure of the bridge. This crack was the result of stresses induced in the vertical truss member from vehicle impacts to the sway braces. A temporary repair was completed on the member and the structure was opened to one lane of alternating traffic. A detailed inspection resulted in such a low sufficiency rating that the structure became the highest-priority replacement need in the state. In December 2014, a temporary detour and crossing of the Dolores River was constructed. The structure was taken out of service with the completion of the detour.
Replacement
From fall 2015 through 2016, the U.S. Army Corps of Engineers (USACE) and CDOT evaluated the bridge as part of Section 106 of the National Historic Preservation Act, a federal law that requires federal agencies to take into account the effects of projects on historic properties. As part of that process, CDOT evaluated whether the bridge could be rehabilitated and left in place, but ultimately determined that it needed to be replaced with a new structure at the same location.
As mitigation for the bridge removal, CDOT completed a National Park Service Historic American Engineering Record (HAER) documentation, which includes archival photos and a detailed narrative of the bridge's history. The bridge was also the subject of high-resolution LIDAR three dimensional scanning so that its structure type can be studied long after its removal. CDOT also made the progressive decision to store the bridge truss for future use, an approach to historic bridge preservation that has been considered but not carried out by the agency before.
In March 2017, the truss was moved off its abutments, disassembled and moved to a storage facility where it will remain until it can be reassembled in a new location. CDOT hopes the bridge will one day be re-purposed for use on a pedestrian/recreational trail so that people can appreciate an historically significant bridge type that is very quickly disappearing from the transportation landscape in Colorado.
Sources:
Blackwell, Chad, et al. Draft Historic American Engineer Record. Dolores River Bridge, HAER No. CO-102. 2016.
Fraser, Clayton. Colorado Historic Bridge Inventory. Historic Bridge Inventory Form. Dolores River Bridge (5MN4955). 2000.
Mead & Hunt Inc./Dill Historians LLC. Colorado Historic Highway Inventory—Historical Summary and Evaluation of Significance. State Highway (SH) 90. 2016.
