Uplift Testing of Model Anchors

Abstract

The results of model tests of 18 ground anchors vertically buried in sand are described in this paper. Also described are tests on half‐section model anchors which were tested to observe movement and behavior during uplift loading of the soil surrounding the anchors. Comparison tests were done to determine the influence of factors such as diameter, fixed anchor length, and buried depth on the uplift capacity of anchors. Two types of failures, deep and shallow, were observed in the tests. The tests showed that top resistance and skin resistance did not occur simultaneously. Peak skin resistance required very little anchor movement, while peak top resistance required substantially more movement. It is concluded that equations currently used to estimate anchor capacity by adding peak skin and top resistance should be modified. Based on the results of the model tests, and confirmed by field tests, an equation was developed for estimating uplift capacity and displacement of anchors.