A Parametric Study On Behaviour of Piled Raft Foundation-Structure Interaction Effects On Seismic Performance of Multi-Story Regular RC MRF Building

Abstract

Present studies show that the effects of Soil Structure Interaction (SSI) may be detrimental to the seismic response of structure and ignoring SSI in analysis may lead to un-conservative design. Despite this, the orthodox design procedure usually involves assumption of fixity at the base of foundation ignoring the flexibility of the foundation, the compressibility of soil mass and consequently the effect of foundation settlement on further redistribution of bending moment and shear force demands. The effects of SSI are analyzed for typical G+15 story regular building resting on raft foundation and piled raft foundation. Two different type of loading pattern (surface load and Point load) and varied raft thickness used for seismic demands evaluation of the target moment resistant frame building. Three-dimensional Finite Element (FE) model is constructed to analyze the effects of soil structure interaction in layered soil condition. Numerical results obtained using soil structure interaction model conditions are compared for surface loading and point loading conditions. The peak responses of maximum settlement, load sharing ratio, shear force in raft and piled raft foundation, bending moment in raft and piled raft foundation, axial force on pile are analyzed.