The Pima County Department of Transportation (PCDOT) sought a value-engineered alternative to conventional methods of slope excavation and stabilization by a system of benched RC retaining walls for steeply sloping bluffs (i.e., high, steep embankments) impacted by roadway widening and re-alignment along the River Road corridor in Tucson, Arizona, USA. Encroachment by the conventional system of a luxury apartment complex located atop one of the bluffs would require relocation of major structures of the complex in an area where property values are among the highest in Pima County. Under these conditions, the cost of the project, including associated land acquisition costs, were deemed to be prohibitive. Value engineering produced a design that utilized soil nails for stabilization of a near-vertical cut slope configuration. The soil nail system also served as support for aesthetically acceptable facing consisting of naturalistic artificial rockwork. The value-engineered alternative resulted in significant savings because the swimming pool, clubhouse, and a two-story apartment building close to the crest of the bluff did not have to be relocated. This paper presents the details of the design including site conditions and geotechnical parameters that had a major impact on the design.
The Pima County Department of Transportation (PCDOT) is in the process of widening and re-aligning River Road, a major arterial roadway in Tucson, Arizona, USA. One section of River Road winds its way around steeply sloping bluffs up to 17 meters high in an area where property values are among the greatest in Pima County. Widening and realignment of the right of way requires considerable excavation of the bluffs and stabilization of the cut slopes through an approximately _-km section in an area where a number of luxury homes and/or apartments are located close to the crests of some of the bluffs.