Settlement of Strip Footings on Sand Subjected to Cyclic Loading

Document Type : Research Article


1 Department of Civil Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran

2 Department of Civil and Environmental Engineering, Amirkabir University, Tehran, Iran

3 Department of Civil Engineering, Ferdousi University, Mashhad, Iran


There are many cases in which the foundation of a structure, in addition to static load, is subjected to cyclic loading, such as earthquakes, traffic loads, and machine vibrations. In this laboratory study, the effect of foundation width, sandy soil density, number of loading cycles, intensity of static and cyclic overheads on cyclic subsidence of strip foundation in dynamic loading has been investigated. The soil material used in this study is poorly grained medium sand (SP). The foundation model has a width of 5, 7.5 and 10 cm and its length is 34 cm. In medium and dense sandy soils, the average amount of foundation subsidence in the first loading cycle is about 46 and 51% of the total cyclic subsidence, respectively. Medium-density sandy soil beneath the foundation has ruptured at a settlement of 22 to 27% of the foundation width. The dense sandy soil beneath the foundation has ruptured at a settlement of 33 to 43% of the width of the foundation. The lower the total overhead entering the soil, the more loading cycles the soil can withstand to break. That is, with increasing static and cyclic overhead, the soil is broken in a smaller number of cycles. Due to the creation of permanent subsidence under the effect of cyclic loads, in designing foundations under the effect of this type of load, the predicted amount of subsidence must be less than the allowable amount.


Main Subjects