GRI provided geotechnical services for the new Peter O. Kohler Pavilion on the OHSU campus in Portland’s west hills. Our services included a detailed geotechnical investigation, development of recommendations for earthwork and site preparation, lateral earth pressures, shoring design, foundation support, slope stabilization, and seismic design considerations. Due to construction challenges associated with the original design of several large retaining walls on this site, the contractor and owner requested that GRI evaluate other retaining wall options early in the construction process. GRI recommended a lightweight Expanded Polystyrene (EPS)-backfilled retaining wall system that significantly reduced excavation, lateral earth pressures, and structural requirements. GRI provided recommendations for a range of possible slope geometries with varying volumes of EPS fill. Specifications allowed field modifications to accommodate the complex site geometry and ever-changing site conditions and access. GRI also redesigned the pavement section for SW Campus Drive to include the use of geosynthetic separation and geogrid reinforcement. GRI also designed an unshored, 35-ft-tall EPS wall for a 1H:1V slope to provide an additional staging area and truck turn-around during steel erection. GRI personnel provided on-site observation services and consultation during construction of the new buildings. The innovative design and construction solutions developed by GRI garnered a Grand Award in the 2005 Engineering Excellence competition sponsored by the American Council of Engineering Companies of Oregon.