Experimentally Studying the Effect of Loading state on the Behavior of Shallow Footing in Sandy Soils

In shallow footings depending on the type of structure which is located on it, such as urban buildings, marine structures, billboards, dams and etc; it is influence by different types of loads, such as vertical, horizontal and bending moment. Depending on the type of structure, These loads can affect the shallow with different loading states. In this paper, by defining 32 experimental tests, the behavior of two circular and square shallow footings located on the sandy soil under the three loading states have been investigated and the failure envelope of each footing have been ploted in the V-H space (vertical load- horizontal load). Also, to study the effect of relative density on the failure envelope using the rainy method, sandy soil with two densities of 50 and 70 percent was developed. The results show that the failure envelope for shallow footing regardless of its shape in the V-H space, follows a second-order function, which the increase of density and consequently the increase of soil friction angle in the sandy soil has a direct impact on the failure envelope in the V-H space; the envelope has a maximum point which is equivalent to 0.3Vmax. The square footing has a bigger ultimate load than the circular footing; that’s why failure envelope in the V-H space for the square footing is larger. In general, the failure envelope in the V-H space for shallow footings depends on the ultimate load (Vmax) and soil friction angel.