Study on Soil Structure Interaction and Base Isolated System for Seismic Performance of Structures Resting on Different Types of Soils

  Dr. S.Amaresh Babu,  Ahmed Zubedi

The conventional approach to seismic resistant design is to incorporate adequate strength, stiffness and inelastic deformation capacity into the building structure so that it can withstand induced inertia forces. This was with the presumption that during strong ground motion, whenever inertia forces exceed their design earthquake levels, the structure will dissipate this excess energy through deformations at predefined locations scattered over the structural framework. It was observed that, even with members designed for ductility, the structures did not always perform as desired. It was realized that a design based only on the principle of incorporating ductility as a safeguard against seismic effects needs a critical review. Engineers came up with the innovative idea of introducing a flexible medium between supporting ground and the building, thereby decoupling the structure from the energy rich components of seismic ground motion. This strategy came to be known as the Base Isolation method.This thesis aims to determine the significance of using Base Isolation as a technique to withstand the seismic forces. This thesis also aims to show the importance to consider soil structure interaction rather than analyzing the structure as fixed base. The comparison is mainly done between structures with soil structure interaction effects and base isolated structures. The analysis is done using computer program SAP2000 v18. The method of analysis is Fast Nonlinear Analysis (FNA). There are 18 models which are analyzed in which there are symmetric and asymmetric in plan models, which are analyzed as fixed base models, models with the consideration of soil structure interaction, and models with base isolation (lead rubber bearing). These models are assumed to be resting on three soil types namely limestone, stiff clay, and loose sand. All the models are G+13 storey. The results show that considering soil structure interaction effects for structures resting on medium and soft soils is more significant when compared to structures resting on hard soil because there is not much difference noticed in the response of structures with and without soil structure interaction effects resting on hard. Also base isolation system is best suited for structures resting on hard soil. The base shear, storey displacements, and torsion are reduced to a great extent

Keywords- Base Isolation, Soil Structure Interaction, Fast Nonlinear Analysis.

Unique Identification Number - IJEDR1904104
Page Number(s) - 618-627
Pubished in - Volume 7 | Issue 4 | December 2019
DOI (Digital Object Identifier) -   
Publisher - IJEDR (ISSN - 2321-9939)

  Dr. S.Amaresh Babu,  Ahmed Zubedi,   "Study on Soil Structure Interaction and Base Isolated System for Seismic Performance of Structures Resting on Different Types of Soils", International Journal of Engineering Development and Research (IJEDR), ISSN:2321-9939, Volume.7, Issue 4, pp.618-627, December 2019, Available at :http://www.ijedr.org/papers/IJEDR1904104.pdf