Best Project, Highway/Bridge: Red Rocks South Ramp Structures

RED ROCKS SOUTH RAMP STRUCTURES

Morrison, Colo.

BEST PROJECT

Submitted by: SEMA Construction

OWNER Denver Dept. of Transportation

LEAD DESIGN FIRM Jacobs

GENERAL CONTRACTOR SEMA Construction

Originally built in the 1940s, two pedestrian access bridges at the southern entrance of the iconic Red Rocks Amphitheater had reached the end of their service life. An emergency retrofit provided temporary stability while work began on a complete replacement.

A $2.3-million effort began during the offseason to minimize disruption to the venue’s schedule. The original structures were outdated and did not meet today’s standards and specifications. The new design incorporates modern guidelines and materials, resulting in a safer and more durable structure. Slightly wider ramps and reduced angles of approach now accommodate the thousands of concertgoers and visitors accessing the amphitheater from the south.

The project replaced two distinct bridges. The lower ramp at 43 ft and the larger upper ramp at 78 ft were connected by 400 ft of 12-ft-wide trails along the rock face. Aesthetic enhancements such as stone veneer faces, concrete staining and decorative bridge rails blend the new structures with the historic aesthetic of the site. Crews also installed an environmentally conscious drainage system with a subterranean 350,000-gallon stormwater facility.

Photo courtesy SEMA Construction, Inc

New cast-in-place abutments and piers were carefully integrated into the rock face, and the bridges were constructed with a combination of precast and cast-in-place deck spans. The bridge approaches had to be precisely keyed into the rock structure. To achieve this without affecting the historic site, crews performed precision hand sawing and demolition.

The confined worksite, combined with the keyway being nearly 80 ft above grade, prevented the use of any large equipment. The contractor collaborated with its equipment suppliers to retrofit a small mini excavator with a larger demolition hammer, enabling the crew to break the rock from above and construct the keyway.

The steep typography also made it impossible for standard drilling equipment to access the site. The contractor utilized lattice cranes to transport and position the drilling equipment from the staging area. This allowed for smaller pads to be used, minimizing damage to existing vegetation and maintaining the integrity of the natural landscape.