Oregon Health & Science University (OHSU) educates health professionals and scientists and provides leading-edge patient care, community service and biomedical research. The expansion of the Center for Health & Healing (CHH) South project includes a new ambulatory care tower, parking garage, and central utility plant, OHSU Guest House, and Skybridges. The central utility plant is connected via an underground utility tunnel of an existing garage that allows the passage of utilities, services, and materials.
The James W. Fowler Company (JWF) was the tunnel subcontractor for the Hoffman Construction Company of Oregon. JWF elected to utilize the engineering services and experience of the McMillen Jacobs Associates to assist in design.
The project consisted of 70 feet of 144-inch diameter steel casing fixed with Permalok joints and was installed in a single drive. Tunnel casing was installed via pipe ramming methods through fill and native material which included; sand, silts, gravel, and pieces of construction debris including cobble sized pieces of asphalt and concrete.
The tunnel was installed from a 40 foot deep soldier pile and lagging shaft which would eventually serve as the basement and central utility plant of the high-rise OHSU Guest House. All tunneling work was executed simultaneously with the erecting of the high-rise OHSU Guest House. From the shaft, the tunnel was installed underneath an active roadway and light rail line with no disturbances. The tunnel was concluded with an underground connection and permanent fixture to an existing parking structure. The final liner of the tunnel included a leveling slab, lighting, and utilities and is suitable for constant personnel traffic.