Red Rocks Amphitheater, Morrison, CO

City and County of Denver

The Red Rocks Amphitheater renovation project involved the stabilization of a large landslide through the seating area, construction of a new visitor center and updates to infrastructure, water and sewer, telecommunications, and accessibility. Yeh and Associates’ role on the project was to provide designs and develop specifications for the project’s retaining structures, landslide mitigation, excavation support and rehabilitation for the historic seating and landscaping features. Retaining structures were designed to conform to the natural setting and emulate the existing historic features. Yeh and Associates also provided construction management support, engineering support, and review of contractor’s methods and submittals along with construction observation and materials testing services.

The 30,000-square-foot visitor center was constructed underground at the top of the Amphitheatre and features state-of-the-art telecommunications capabilities, exceptional lighting, amazing terrace views, an elevator to accommodate individuals with disabilities, and new restrooms. The final finishes at the visitor center included a restaurant, a meeting facility, and an incredible display showing the amphitheatre’s geologic evolution and entertainment history.

The visitor center was designed with soil nail walls ranging in height from 10 to 35 feet in cut sections adjacent to the historic amphitheater seating. A natural rock face mechanically stabilized earth (MSE) retaining wall was designed in the western fill section.The MSE wall ranges from 2 to 32 feet in height, varying with the natural topography. The landslide stabilization along the south stairs and seating area was designed with three separate ground anchor walls to accommodate potential movement of the steep slope and adjacent structures. Compaction grouting and reinforced soil slope were used to mitigate settlement of this area. Highly variable subsurface conditions and limited access complicated the design process. Materials onsite range from very competent sandstone to loose fill with numerous voids. During Red Rocks’ original construction during the late 1930s, fill material was placed under the seating area. Over time, this material mobilized, creating numerous cracks and distressing the historic features. Seismic refraction surveys and ground penetrating radar were used to model the subsurface conditions and then stabilization and densification methods to mitigate the damage were developed.

Yeh’s key personnel that worked on the project included Shan-Tai Yeh who was the QA/QC reviewer, Rick Andrew was the project manager and Ben Arndt was the project engineer.