Idaho Springs, Colorado, located approximately 30 miles west of Denver, was once a mining town. Today, the city of nearly 1,800 people is a great place to go whitewater rafting, hike trails, and more. The Colorado Department of Transportation (CDOT) is in the middle of a project along the frontage road of Interstate 70 in this area, called County Road 314, that will benefit drivers, hikers, and bicyclists.Near the work site are Veterans Memorial Tunnels and I-70. Commuters use CR 314 as a shortcut when I-70 backs up. The route is also periodically used by emergency vehicles.

The 1.5-mile stretch of CR 314 isn't fully paved – some sections are dirt – and is narrow at just one and a half lanes wide. In addition, there’s a precarious drop to Clear Creek, which flows along the road and a horseshoe turn, but there is no guardrail.

Upon completion of construction, there will be one 11-foot lane in each direction with 2-foot shoulders on the majority of the route and an 8-foot-wide bike path.

Other work includes the installation of retaining walls and guardrails, a pedestrian bridge over Clear Creek, drainage improvements, erosion control, and updated signing and striping.

In 2016, work began on the Peaks to Plains Trail, a 65-mile corridor that starts in Denver and goes west to the Continental Divide. The multi-use trail is slowly but surely being constructed. Part of the trail runs near the CR 314 project site.

The Scott Lancaster Memorial Bridge is a pedestrian bridge that crosses over Clear Creek. The team needed to move the bridge because it was not up to current safety standards. Lancaster, a native of the area, died in 1991 at the age of 18. He was killed by a mountain lion while on a training run.

In addition to moving the Lancaster Bridge, the project required a new steel pedestrian bridge to cross Clear Creek. Placement of the new pedestrian bridge was a challenge due to overhead power lines. It arrived on site in parts, and the team bolted it together.

"We wanted to preserve the Lancaster Bridge because it’s valued by the community,” says Kevin Brown, a Resident Engineer for CDOT, who is overseeing the project. The bridge was moved just 500 feet away and now includes documentation explaining Lancaster’s story.

Despite the small distance, moving the bridge was a challenge. The hand-built bridge, which had wooden poles bolted together to act as beams, didn't have any existing plans. The team didn’t even know how much the bridge weighed.

Through engineering, they were able to determine some details, including a weight estimation. A crane was used to move the bridge. “The team handled the bridge very carefully and managed to preserve it while moving it,” Brown says. A gravel trail was added to the bridge’s new location, making it easier for tourists to view it.

The 1.5-mile-long project area is very constrained. Besides the natural elements such as mountains and the creek, there’s an old electrical training station that the team was careful not to disturb.

“Half of the project site is shaded 90 percent of the time in winter,” says Jamie Klassen, a Project Engineer for American Civil Constructors (ACC), the general contractor on the project.

There’s also a variety of soil types in the area. “Some of the soil types we discovered aren’t standing up as we expected, which means greater quantities were needed to support the retaining walls,” Brown says.

Because of these natural challenges, the team has had to use five different wall types. The variety is based on the mountain, soil, and the work done in the area. Two different wall types were adjacent to each other. This has been challenging for the contractor in regard to scheduling since different subs worked on each wall type and material supply.

One wall type – winter-proof mechanically stabilized earth walls – was prioritized on this project. The cold and harsh winter conditions led to the need for this type of wall on this project. An INFRA grant was secured for this project. The state kicked in the rest for the $8.7 million project.

The project began in October 2021 and is scheduled to be complete in September 2023. Currently, the project is on schedule. The team has accomplished this despite the linear nature of the work – they can only do one operation at a time due to the various constraints.

While the roadway has been closed to motor vehicles during construction, pedestrian and bike access has been maintained. This helps keep the project moving forward.

Brown notes that the contract included a certain number of workdays on the project. The clock stops during the winter, but the contractor is permitted to work if they choose.

ACC has worked during their free time, which Brown says has been key in keeping the project on schedule. “They utilized the winter shut down time to catch up and get ahead despite challenges.” Besides the surprises with the soil, the team has had some slowdowns due to utility issues.

Another way the team has kept the project moving through winter is by using a specially designed crushed aggregate that is winter proof.

When the project completes later this year, the Peaks to Plains Trail will be one step closer, hikers will be able to enjoy the tribute to Scott Lancaster, and local drivers and emergency vehicles will have a reliable and safe alternative to I-70.