US6 & 19th Street “Linking Lookout” Interchange Golden, Colorado

To serve as an urban park as well as a major multi-modal transportation conduit, the Linking Lookout Interchange is designed to improve connectivity on each side of US 6 in Golden, Colorado. The two-span, 160-foot-long and 280-foot-wide bridge improves vehicular level of service while increasing safety for what had been one of the area’s most accident-prone intersections. As the structural engineer-of-record and a subconsultant to IMEG, the Otak design team worked closely with Edward Kraemer and Sons, the CMGC, to develop the design, construction phasing, and construction cost estimates for this $30 million project.

A Structure Designed to Safely Add Multimodal Connectivity and Public Space

The overall concept was to improve connectivity from the residential areas on the west side of US 6 to the Colorado School of Mines campus located to its east. The multimodal design now allows vehicles, bicyclists, and pedestrians cross safely over the busy highway on their way between downtown Golden and other local destinations. Comprised of side-by-side, pre-stressed girders, the bridge the bridge has nearly 70,000 square feet of retaining walls are soil-nail and MSE. To create an urban park setting, up to 10 feet of fill and trees were added on top of the bridge deck, along with picnic tables, park space, and a small amphitheater. To minimize the load on the structure, earthen fill was replaced with styrofoam block in critical areas. Waterproofing of the bridge deck, below the earthen fill, was a critical consideration because the structure would be covered by earth, grass, and pavement, and could not be inspected from above.