Oregon Health and Science University (OHSU) is a well known academic institution providing comprehensive health care service as well as educating health professionals and scientists on leading-edge patient care, community service, and biomedical research. OHSU has been doing much good for the area through medical support and is involved in numerous researches, including cancer research. OHSU’s needs for growth includes the addition of a building that will provide additional floor space and house patients.
OHSU’s Center for Health and Healing (CHH) South building is a needed addition; it includes an ambulatory care tower, a parking garage, a central utility plant, an OHSU guest house, and sky bridges. An underground utility tunnel connects the central utility plant to an existing garage, which allows utilities, services, and materials to pass through.
James W. Fowler Co. acted as a tunnel subcontractor for Hoffman Construction Company and through the design-build contract, oversaw tunneling as well as assisting with its design. JWF utilized the chartered engineering services and experience of McMillen Jacobs Associates to help with the design.
The project required a 40 ft deep soldier pile and lagging shaft, which is currently utilized as the basement and central utility plant for the high-rise OHSU guest house. From the shaft, tunneling was executed simultaneously while erecting the high-rise OHSU guest house. The tunnel required 70 ft of 144-in diameter steel casing fixed with Permalok joints and was installed in a single drive. Tunnel casing was installed using pipe ramming methods through fill and native materials; including sand, silts, gravel, and construction debris such as cobble-sized pieces of asphalt and concrete.
Upon completion, the tunnel formed an underground connection and permanent fixture to the existing parking structure. The tunnel is lined with a leveling slab, lighting, and utilities and is suitable for constant personnel traffic. The tunnel was successfully installed underneath the shaft, active roadway, and light rail line with no disturbances.