Effect of soil stiffness on seismic response of reinforced concrete buildings with shear walls

B R Jayalekshmi,H K Chinmayi

doi:10.1007/s41062-016-0004-0

B R Jayalekshmi, H K Chinmayi

Open Access

https://doi.org/10.1007/s41062-016-0004-0

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Abstract

Buildings are subjected to lateral loads caused by wind, blasting and earthquakes. The high stresses developed by these loads literally tear the building components apart, which are in general designed for gravity loads. To resist these lateral forces, shear walls can be introduced in buildings. Present study aims to determine the apt shear wall position which attracts the least earthquake forces in symmetric plan multi-storey buildings. Dynamic response of a structure is significantly influenced by the underlying soil due to its natural ability to deform. Three dimensional finite element soil–structure interaction analyses of reinforced concrete shear wall buildings with shear walls placed at various locations is carried out in time domain using scaled down Elcentro ground motion to determine the seismic response variation in the structure due to the effect of stiffness of soil. Four different soil types based on shear wave velocity and six varying shear wall positions in multi-storey buildings up to 16 storeys are considered to determine the effect of soil–structure interaction. From the study, it is found that structural response as per conventional fixed base condition is very conservative. For buildings founded on soil with Vs ≤ 300 m/s, providing the shear walls at the core is advantageous whereas for soil with Vs > 300 m/s, the shear walls placed at exterior corners of the building attracts the least earthquake force.

Highlights

Soil–structure interaction (SSI) is an interdisciplinary field which involves structural and geotechnical engineering
Three dimensional finite element soil–structure interaction analyses of reinforced concrete shear wall buildings with shear walls placed at various locations is carried out in time domain using scaled down Elcentro ground motion to determine the seismic response variation in the structure due to the effect of stiffness of soil
Four different soil types based on shear wave velocity and six varying shear wall positions in multi-storey buildings up to 16 storeys are considered to determine the effect of soil–structure interaction

Summary

Introduction

Soil–structure interaction (SSI) is an interdisciplinary field which involves structural and geotechnical engineering. The dynamic response of a structure depends on the properties of underlying soil, structure and nature of excitation. The process in which, the response of the soil influences the motion of the structure and vice versa, is referred to as SSI. The conventional non-interaction analysis of buildings without considering the influence of the soil results in design which is either unnecessarily costly or unsafe. The interaction between the structure and the soil need to be considered and modelled accurately in order to design earthquake resistant structures and to evaluate the seismic safety of the building. SSI problem has become a significant feature in structural engineering as it is inevitable to build important structures in locations with less favourable geotechnical conditions like seismically active regions

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