Estimation of seismic uplift capacity of horizontal strip anchors using pseudo-dynamic approach.

Abstract

In this paper, an analytical method to compute the vertical uplift capacity of horizontal strip anchors under both static and seismic conditions is described by using limit equilibrium method and Kötter’s equation. For seismic forces, pseudo-dynamic approach is used to obtain the net seismic vertical uplift capacity factor for unit weight component of soil (Fγd) by considering the distribution of soil reaction on the simplest planar failure surface through the use of Kötter’s equation. Results under static and seismic conditions are determined for various combinations of input parameters, like soil friction angle, embedment ratio, soil amplification and both horizontal and vertical pseudo-dynamic seismic accelerations. It is observed that Fγd decreases significantly with increase in both horizontal and vertical seismic accelerations and soil amplification. As expected, the seismic uplift capacity increases with increase in embedment ratio and soil friction angle. Results in terms of non-dimensional net seismic uplift capacity factor are presented in graphical form. Present results are compared and found in good agreement with few similar results available in literature. Present study reveals lowest critical design values of seismic uplift capacity factor which can be used in seismic design of anchors.