Reliability-Based Fragility Analysis of RC Frame Buildings Considering Soil-Structure Interaction

1. Introduction

The characteristics of strong ground motion of an earthquake plays an important role on damage and destruction of structures. Soil play an important role in ground motion characteristics ((Nabilah et al., 2019) (Kumar et al., 2018) (Shiuly et al., 2014) (Kumar & Krishna, 2013) (Sitharam & Vipin, 2010) (Boominathan & Krishna Kumar, 2010)). Ground motion for a far source seismic event is ominously dissimilar than close source seismic event. It is to be noted that near source earthquake consists both high and low frequency seismic wave, whereas far source earthquake consists only low frequency wave. Thus, respons of structure demonstrates amply difference for the two types of earthquake. It is to be mentioned that Soil Structure Interaction (SSI) effect is neglected in conventional earthquake analysis of structure. However, it has been observed that SSI plays an important role in variation of damage destructions of structures. On the basis of the type of soil and structure, the free-field response of a particular site may be amplified ominously due to SSI effect.

Several researches have conducted research on SSI effect in past. The procedure for determining the effects of inertial soil-structure interaction on structural response was demonstrated by Stewart et al. (1999). The effect of soil-structure interaction during the analysis and design of a six storeys RC frame building having basement was analysed by García (2008). Mylonakis et al. (2018) conducted research on the effect of SSI on the structural response subjected to earthquake motion and determined response spectrum specified in code along with amplified fundamental period and effective damping for the SSI. Anand et al (2010) defined the seismic behaviour of RC buildings with and without shear wall under various soil conditions incorporating SSI effect. The idealised 2-D finite element modelling of dynamic SSI assuming plane strain condition using Abaqus (v.6.8) software was performed by Matinmanesh et al. (2011). Priyanka et al. (2012) evaluated the effect of SSI on multi-storeyed buildings having various foundation systems. The dynamic behaviour of building frames on raft footing under seismic excitations incorporating the SSI effect was investigated by Kuladeepu et al. (2015). Gaikwad et al. (2015) investigated the effect of bare frames and in-filled frames considering effect of soil under seismic excitation. Several researchers conducted researches on the SSI effect due to far field and near field seismic event. Ghannad et al. (2008) explored the seismic response with SSI based on the concept of cone models subjected to near fault ground motions. Zhang and Tang (2008) conducted numerical modelling dynamic SSI by a lumped two degree of freedom system which was subjected to pulse like near fault ground excitation. A parametric study was performed by Azarhoosh and Ghodrati Amiri (2010) considering the elastic response of different SSI systems having shallow foundations and exposed to synthetic pulses and near fault excitations. Minasidis et al. (2014) inspected SSI effect of the response of 2D steel frames subjected to near fault earthquake excitation. Gelagoti et al. (2012) studied the seismic performance of rocking isolated frame structures considering SSI by employing nonlinear FEM. In this study near source ground motion was used to determine factor of safety against toppling collapse of the structure. Davoodi and Sadjadi (2012) evaluated response of single degree of freedom (SDOF) system with considering SSI subjected to near field and far field ground motion. the useful effect of allowing soil and structure uncertainties of different parameter on the soil-structure response was discussed by (2018).