Behaviour of plate anchors under short-term cyclic loading

This paper reports the behavior of circular plate anchors, buried in soft saturated soil under short-term cyclic loading. The principle parameters studied are the effect of cyclic load ratio level (CLRL) and time period of loading cyclic on anchor movement. Further the effect of pre-loading on the movement of anchors in subsequent loading stages and post-cyclic monotonic load-deformation bahaviour of anchors have been reported. The experimental results indicate that for low intensities of cyclic loading i.e. CLRL of 0.15 and 0.30 elastic equilibrium of anchor movement is attained after few cycles of loading. But for higher CLRL an unceasing anchor movement is observed with loading cycles. The degradation in cyclic stiffness increases with increase in amplitude of cyclic loading. Time period of loading cycles have showed considerable effect on movement of anchors. For given duration of loading, higher frequency cycles cause more movement of anchors than lower frequency cycles. Pre-loading reduces the movement of anchors in subsequent stages. Post-cyclic monotonic pullout test showed an increase in initial stiffness of anchors whereas the peak pullout load was found to decrease marginally over that of an anchor not subjected to any cyclic loading. To prevent any substantial movement, the amplitude of cyclic loading should be kept below 30% of the static anchor capacity.