Industry paper

U.S. Bank Stadium Geosynthetic Reinforced Stress Relief Wall: Design, Construction and Fire Damage Mitigation

Authors: Nathan M. Lichty, P.E., Stephan M. Gale, P.E., and Tim Bendell

Demolition of the Old Metrodome Stadium in Minneapolis, MN occurred in 2013 and subsequent reconstruction of U.S. Bank Stadium, the home of the Minnesota Vikings and host of the 2018 Super Bowl, occurred between 2014 and 2015 on the same site. Stadium construction included an approximately 9.1m (30ft) tall, 213.4m (700ft) long, Geosynthetic Reinforced Soil Structure (RSS) constructed as a below-grade stress relief wall along the entire south side of the stadium. The RSS, constructed using polyester geogrid reinforcement with a high tenacity polypropylene woven geotextile wrap and welded wire basket facing, was placed at a 1m (3ft) offset from the bottom of the Stadium’s south foundation wall. The RSS was battered 2.5 cm (1 inch) per each 46 cm (18 inch) vertical wire basket resulting in a void at the top of about 1.6 m (5ft). The void was spanned by a precast concrete slab. Significant construction challenges included: altering of the site and utility plan for RSS construction, a unique RSS geometry, reinforcement diversion around utilities and structures and fire damage remediation. Cost savings from using a geosynthetic reinforced stress relief wall on a spread footing instead of a concrete cast-in-place wall on a deep drilled pier foundation on bedrock was estimated at $5.5 million. The 9.1m (30ft) tall cast-in-place concrete foundation wall would have needed to be supported on a deep drilled pier foundation because of the lower bearing capacity of the moderately weathered limestone bedrock at the base of the wall.