A PARAMETRIC STUDY OF RAFT FOUNDATIONS

Abstract

A raft foundation is usually a concrete slab with constant thickness throughout its plan area. Such foundations are most commonly used where the soil has low bearing capacity or there is a possibility of differential settlement. Raft foundations can be classified as flat plate type raft, raft with column pedestals, slab and beam raft. etc. To analyse the raft foundations, finite element method is used by considering the following parameters. Coefficient of subgrade reaction of soil Number of storeys in the building Variation in column spacing The results of this analysis gives the following information The thickness of raft slab Effect of soil stiffness on material quantities Effect of soil stiffness on cost These results will be useful in making preliminary estimates of quantities of materials and cost of raft foundations for buildings with respect to the parameters mentioned above.