Investigation of pullout load capacity for helical anchors subjected to inclined loading conditions using coupled Eulerian-Lagrangian analyses

The pullout load carrying behavior of helical anchors for inclined loading conditions was investigated based on the coupled Eulerian-Lagrangian (CEL) analyses. Various types of helical anchors, specified as Types 1 to 6, were adopted in the analyses. Types 1, 2 and 3 represent those with one, two, and three equal-diameter helical plates and Type 4 was a helical anchor type with two helical plates of different diameters. Types 5 and 6 were both with three helical plates of different diameters in opposite diameter configurations. Inclined loading conditions affected the pullout capacity (Qu) of helical anchors producing lower Qu with increasing load inclination. The patterns of the Qu decrease with increasing load inclination were similar for all helical anchor types considered in this study. The values of Qu were approximately similar up to θ = 60° and then decreased continually with furthering increasing θ. Qu was lowest at θ = 90°. The top-down increasing diameter configuration of helical plates was more efficient than the bottom-up increasing diameter configuration. A normalized load capacity relationship was proposed, which can be used to evaluate Qu for inclined loading conditions. The pullout behavior of helical anchors was governed by helical plates with marked effects of helical plate configuration, which was however less pronounced with increasing θ.