Permanent earth anchor (tieback) system for the Stanford Linear Collider

Construction and performance of a permanent earth anchor (tieback) system for the Stanford Linear Collider.

The Stanford Linear Collider is the newest addition to the high-energy physics research complex at the Stanford Linear Accelerator Center. One of the many unique features of this project is the large, underground pit, where massive particle detectors will study the collision of subatomic particles. The large, open pit utilizes nearly 600 permanent earth anchors (tiebacks) for the support of the 56 ft (17 m) high walls, and is one of the largest applications of tiebacks for permanent support of a structure. This paper examines the use of tiebacks on this project with empbasis on their installation and performance. 

In general, tiebacks (earth anchor) have gained widespread acceptance for use in temporary earth-retaining structures. They eliminate the need for large, open excavations with sloped sides, or the need for internally braced sheeting. For large, deep excavations, tiebacks (earth anchor) become economically feasible. Relative to conventional cantilever retaining walls, tieback walls do not need large footings and the costly over-excavation and backill. The use of tiebacks has become popular for tight construction sites in urban areas where space is limited by adjacent structures, and in subway,bridge abutment, and highway retaining wall construction. Their use in temporary structures, and more recently in permanent structures, has been documented by Weatherby (1982) and Anderson (1984).