Experimental investigation of shell foundations on dry sand

Shells are usually used as structural elements in buildings. In Germany the y showed remarkable resistance to the effects of bombing during World War I I. About 1 decade later, the possibility of employing shells in foundation engineering was explored. Surveys of the literature indicate that shell fou ndations have been employed effectively in different parts of the world and were proven to provide an overall economical alternative to the convention al flat foundations. However, the geotechnical design of these footings rem ained the same as for their respective flat ones. Accordingly, the advantag es of shell geometry in foundation engineering has not yet been explored in the design of these footings. The objective of the present study is to exa mine the overall geotechnical behavior of three types of shell foundations resting on sand under axial loading conditions, namely, triangular, conical , and pyramidal shells. Furthermore, the resulting bearing capacities and s ettlements will be compared with conventional strip, circular, and square f lat foundations. The present paper presents an experimental study on nine f oundation models tested on loose, medium, and dense sand states. The influe nce of shell configuration and embedment depth on the ultimate bearing capa city and settlement will be presented. The results of the present experimen tal investigation have shown the admirable performance of shell foundations with respect to ultimate bearing capacity and settlement characteristics. Shell foundations provide higher resistance to lateral loading as compared with flat ones, and thus they will perform better in earthquake regions.