Influence of prestress on the dynamic response of ground anchorages

An investigation of both the static and dynamic performance of ground anchorage systems, involving measurements on active construction sites, reinforced by laboratory and computer modeling, started at Aberdeen University in the early 1980s. The work has concentrated on resin bonded rock bolt anchorages and has led to the development of a new method for the nondestructive testing of anchorages. Part of the research program was undertaken to assess how changes in the prestress load influence the dynamic response of an anchorage and led to the capability of the new testing method to determine variation in frequency response with changes in prestressing. The program has included development of a lumped parameter model to simulate the response of anchorages to changes in prestress and impact load. The head of the anchorage has been shown to be the most influential component in determining response. The following paper presents results which have arisen from the analysis undertaken to date on this improved lumped parameter numerical model.