Wire Cable Failures in Climbing Anchor Chocks
Anchor chocks are used in the sport of rock climbing for providing secure attachment to a rock face. They are used at regular intervals and must be light weight (since many are carried) and also sufficiently strong to withstand an impact force should a climber fall from a height. In chock design, steel wire cable is widely used for connecting the nut component, which is wedged into a rock crevice, to the free end which attaches, via a karabiner link, to the safety rope. However, the wire cable is vulnerable to failure as it can fray with use at exposed ends - especially when folded into a loop using tight bends. Also, the ferrule end connections are considered a potential design weakness. In a research programme tests have been carried out on new and also some well used anchor chocks and has revealed very different, and some unpredicted, failure modes – depending on the state of the wire rope and whether the applied load at failure was static or impact. This paper presents the results of test failures for a range of chocks and discusses the benefits of using single lengths of wire cable with suitably swaged end ferrules.
J. Alfaiate, M.H. Aliabadi, M. Guagliano and L. Susmel
J. Vogwell and J. M. Minguez, "Wire Cable Failures in Climbing Anchor Chocks", Key Engineering Materials, Vols. 348-349, pp. 165-168, 2007