عنوان مقاله [English]
In some structures, such as oil platforms and wind turbines, depending on the type of utilization, the footing is subjected to combined vertical load, horizontal load and bending moment (V-H-M). In this study, the behavior of the ring footings resting on sand subjected to combined V-H-M loading is experimentally investigated by conducting 100 tests using six load paths. Three values for the diameter ratio of the ring footing models are assumed, including n = 0.2, 0.4, and 0.6, along with a circular foundation (n = 0). The failure points were determined, on the basis of load-settlement diagrams, and by using the set of these points, the failure envelope was plotted in the vertical load-horizontal load, vertical load-bending moment and horizontal- bending moment spaces. This failure envelope follows a parabolic curve in V-H and V-M / B space, The results indicate a parabolic curve for the failure envelope in V-H and V-M/B spaces which is dependent upon the diameter ratio. Moreover, the most efficiency of a ring footing during eccentric or inclined loading takes place when n is within a range from 0.2 to 0.4.