Behavior of Grouted Anchors Subjected to Repeated Loadings in Field

Abstract

This paper presents the results of full-scale repeated-loading tests performed on three prestressed and six passive anchors grouted to various lengths in a rock mass. Different levels of prestress load, ranging from 22% to 73% of the ultimate static load, were applied to the prestressed anchors. Different levels and amplitudes of repeated loads, ranging from 10% to 170% of the initial prestress load and from 10% to 73% of the ultimate static load, were applied to prestressed and passive anchors, respectively. The results have shown that the anchors subjected to repeated loadings have the same service life as those only subjected to static loading, provided that the applied repeated loads are less than the initial prestress loads for prestressed anchors, or less than 30% of the ultimate static loads for passive anchors. Based on this research, it is suggested that grouted anchors subjected to repeated loadings should be prestressed to loads greater than any likely load fluctuation, and the design capacity of the anchors should be 70% of the static load holding capacity.