The Grand Avenue Bridge Project, the largest Colorado Department of Transportation (CDOT) construction project on the state’s Western Slope in three decades, has reached completion. The project, with a total cost of $126 million, included a new Grand Avenue Bridge and adjacent pedestrian bridge (total construction cost is approximately $77 million). Construction on the Grand Avenue Bridge (GAB) project began in January 2016 and was substantially finished this summer. The vehicular bridge itself was judged to be functionally complete, and opened to traffic, 10 days ahead of schedule.
As Colorado DOT Region 3 Communications Manager Tracy Trulovepoints out, “The Grand Avenue Bridge serves as an important connection between downtown Glenwood Springs, the historic Hot Springs District, and Interstate 70, and is the gateway to Aspen and the Roaring Fork Valley.”
The new traffic bridge replaces a nine-span, 676-foot-long bridge that was built in 1953 and had come to be deemed “functionally obsolete”. This previous bridge suffered from several structural and functional deficiencies – narrow lanes, insufficient vertical clearance for railcars, and closely-spaced piers that caused a “pinch point” on I-70.
The replacement traffic bridge structure combines two bridge types. The first section is a five-span, 783-foot, 3-inch, continuous steel trapezoidal tub-girder bridge; the second portion of the bridge is a 198-foot, 2-inch cast-in-place bridge.
The new pedestrian bridge included in the project, replacing a structure that was built in 1985, is a connection that ties the north and south downtown districts together. The path has four bump outs and two canopies for the public enjoy views of historic downtown Glenwood Springs, as well as the natural beauty of Glenwood Canyon and the Roaring Fork Valley.
Funding From Colorado’s Bridge Enterprise
The GAB project was funded via Colorado's special Bridge Enterprise Fund pool of money, the Colorado Bridge Enterprise (CBE) was formed as part of the FASTER (Funding Advancement for Surface Transportation and Economic Recovery) legislation. It operates as a government-owned business within CDOT. Its purpose is to finance, repair, reconstruct and replace bridges designated as structurally deficient or functionally obsolete, and rated “poor."
To accomplish this goal, a bridge safety surcharge ranging from $13 to $32 was imposed on vehicle registration based upon vehicle weight. Revenues from the bridge safety surcharge fee are estimated to generate approximately $100 million in annual funding.
As Trulove explains, “The Grand Avenue Bridge is one of approximately 150 bridges in the state that has a ‘poor’ rating, and therefore had priority for funding. CDOT and the Federal Highway Administration Administrations initiated a formal Environmental Assessment process to determine the alternatives for rehabilitating or replacing the bridge in November 2011.
“In November 2015, the CBE approved the supplemental budget required to allow the GAB project to proceed to construction. The final budget for all phases of the project was funded by the Colorado Bridge Enterprise, CDOT, contributions from utility companies, and several local governments.”
Joint Venture Integral Part of Project from the Start
The contractor for the GAB project is the Granite/RLW Joint Venture; the Joint Venture and the two contracting firms are based in the Salt Lake City area. Tsiouvaras Simmons Holderness of Greenwood Village, Colorado, designed the vehicle bridge and AMEC Foster Wheeler of Denver, Colorado, designed the pedestrian bridge.
The project utilized the Construction Manager/General Contractor method of project planning – allowing the construction management team to be an integral part of the design process for several years before actual construction began.
Granite Construction’s Pat Kalisz, the Project Manager for the GAB project, relates, “We were awarded the CM portion of the project in early 2013. We consulted during design, then priced out the work, and were awarded the project at the end of 2015. After receiving the Notice to Proceed on January 5, 2016, we started construction the next day.
“During the design phase, we provided multiple bridge types as well as different ABC methods to CDOT to help them with the bridge type selection,” says Kalisz. “We provided them with our preferred method for construction phasing and overall project impacts to help them with the environmental document – this helped them narrow down the environmental document a little bit to what was actually going to be built. Working with CDOT and the designers for two-and-a half years allowed us to have a really good working relationship with the project team, and this carried over into the project construction.”
Colorado River and Limited Work Area Among Project Challenges
The project team had to address several construction obstacles, related to scheduling and phasing – with the Colorado River being perhaps the most critical challenge. Faced with limited space to position cranes to erect the new bridge, Granite/RLW created more room on both shores by building causeways, using more than 23,000 tons of rock and other material.
Kalisz reports, “We actually needed the south causeway for the majority of construction, because the bridge spans I-70, the Colorado River, and the Union Pacific tracks without anywhere to stage cranes, man-lifts, or any other construction materials or equipment.
“The first year and a half we had to build the pedestrian bridge along with about 60 percent of the vehicle bridge. We could not have causeways on both banks of the Colorado River during peak flows, in order to maintain safety for the water users during this time. So, we constructed a wall on the north side to utilize during construction prior to the shutdown of the old bridge. Right before the shutdown we put in the north causeway during low flow times, so we could have that work platform to utilize.”
The timing of the causeway’s construction was also contingent on the start of the trout spawning season, Kalisz adds. “We had to install this rock and materials before March 1 due to fish spawning, so during that first winter this was one of the first things we had to get working on was installing the south causeway prior to this hard completion date. This was a challenge as we had a cold and snowy first winter.
“Hauling from the pit when it was snowing was difficult, so we worked just about any day that it didn’t snow. We also had to get a lot of trucks into downtown Glenwood Springs and dump the rock into the river with minimal disturbance to all.”
Tight Time Frame for Primary Traffic Route Closure
The need for rapid construction was the chief issue in designing the new bridge. Few viable alternate routes exist through Glenwood Springs, so taking the crossing out of service for an extended period meant that the community that had to find alternate ways to access businesses, commuter routes, and emergency services.
CDOT declared that 95 days was the maximum time the community could be without its primary road between downtown and the famed hot springs, across the Colorado River to the north. However, thanks to careful planning, collaboration, few injuries and good weather, CDOT and the project team determined the functionally complete bridge could be opened 10 days ahead of schedule, earning Granite/RLW a $250,000 bonus.
“A critical component of the Grand Avenue Bridge project was the traffic bridge detour necessary to replace the old bridge,” says Trulove. “In order to achieve manageable traffic delays during the detour, a comprehensive transit plan was developed, which offered 15-minute peak-hour service throughout the critical service area, and all new bus routing was designed.
“This initiative’s goal was to reduce traffic by 35 percent, or 700 vehicles per hour. Removing one out of every three cars off the road was an unheard-of goal and required buy-in from a large majority of the public. Coordination from communities across the Roaring Fork and Colorado River Valley’s was critical. Getting more people to ride transit, carpool, bike, and walk during the detour was not only necessary, but necessary for the successful completion of the final bridge connection over the Colorado River.
“As a result of these measures, CDOT estimates that traffic through the detour was reduced by approximately 25 to 30 percent, depending on the day. While below the original 35 percent goal, it was still an unprecedented reduction in traffic volumes, and it eased congestion just enough to make the detour work.”
Adds Kalisz, “I think the main reason for the bridge opening early was a lot of early and on-going planning from the entire project team and community. Everyone really saw this was going to be a big impact and for the most part everybody helped come up with solutions. We were planning during the design phase and this continued throughout the construction phase and really ramped up the winter prior to the shutdown. We were able to schedule crews, material deliveries, work schedules down to the day, equipment and start, having contingency plans for anything that we could think of.
“Also, the project team started meeting with task forces to help ensure the detour would work – these task forces included community leaders, stakeholders, emergency response teams, hospitals, river uses, etc. We extended this outreach to communities that were going to be affected by this detour in approximately a 50-mile radius. In my opinion, all of the pre-planning and teamwork really contributed to the successful opening of the bridge and roadwork 10 days early.”
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