Indrajit Chowdhury

Seismic response of rectangular liquid retaining structures resting on ground considering coupled soil-structure interaction

Seismic response of water tanks resting on ground has been a topic of considerable research in academics as well as energy and infrastructure industry. In many cases, it remains essential that they remain functional even after a major ground shaking. State of the art adapted in different national and international code usually recommends a simplified mathematical model that in many cases digresses from field reality. A three dimensional analysis of the tank plus fluid and foundation soil is surely possible based on finite element analysis. However, in most cases, such exhaustive analysis is done away with, often due to lack of supportive software to tackle such problem, but more out of economic and schedule compulsion, where in many cases engineers do not have the luxury to carry out such expensive analysis, to remain competitive in the market. Thus, a search for a better and more realistic model than what is in vogue is still in quest for this particular problem. Present paper attempts to present a mathematical model based on Lagranges formulation and adapting Galerkins technique that circumvents many of the problems as cited above.

Dynamic response of cylindrical structures considering coupled soil-structure interaction under seismic loading

This paper attempts to develop a mathematical model for estimating the seismic response of a cylindrical shaped nuclear reactor building resting in an elastic halfspace considering foundation compliance. Most of the research carried out on this topic has either been carried out by resorting to finite element method (FEM) which makes the computational cost expensive or based on the simplifying assumption of assuming the cylindrical structure as a multi degree lumped mass stick model with soil coupled as boundary springs. In the present paper an analytical model has been developed in which the deformation of the cylindrical body (including its shear deformation characteristics) has been taken into cognizance and then coupling with foundation stiffness a comprehensive solution has been sought based on Galerkin’s weighted residual technique. The results are finally compared with FEM to check the reliability of the same. The results are found to be in good agreement with the detailed finite element analysis.

Analysis of Water Tanks Under Earthquake Force

Water has always remained an essential natural commodity for survival of a human habitat. One observes that, from early dawn of history, human civilization has always thrived near water bodies.

Soil Dynamics and Earthquake Engineering

Though soil dynamics as a formal topic of study in civil engineering was prevalent since 1936 (mostly related to machine foundations), yet its metamorphosis to a new subject termed geotechnical earthquake engineering that is worthy of special attention was quite late.

Seismic Design of Shallow and Deep Foundations

This chapter deals with the design of shallow and deep foundation under seismic load. However, those who are conversant with design of structures under seismic load might wonder as to what is so special about it? Most of the codes around the world recommend an increase in allowable bearing capacity of soil by about 25% under seismic load combination for design of shallow foundations.

Earthquake Analysis of Tall Chimneys and Stack-Like Structures

Tall chimneys and vertical self-supporting vessels are an important feature of power and petrochemical industry. Damage to them during an earthquake can have a severe consequence both in terms of economy and loss of human life.

Earthquake Analysis of Earth Retaining Structures

Retaining walls supporting earth make an important component in infrastructure works like highways, roads, ports, bridge abutment.

Basic Mechanics of Earthquake-Resistant Design

In this chapter, we will look into the analytical aspects of earthquake-resistant design of structures. It will show you systematically as to how the technology gradually developed from simplified equivalent static analysis that was practiced in infancy of earthquake engineering to sophisticated linear and nonlinear dynamic analysis that has become the present state of the art.

Geotechnical Considerations for Seismic Analysis

In this chapter, we will discuss the geotechnical considerations that are relevant to earthquake-resistant design of a structure and also the pertinent parameters that are part of a successful dynamic soil–structure interaction (DSSI) analysis.

Dynamic Soil–Structure Interaction in Earthquake Analysis

In the last thirty years or so, the dynamic soil–structure interaction (DSSI) has undertaken giant leaps in terms of application. From being perceived initially as a utopian exercise in the realms of theoretical physics (understood by few), in the early 1960s it has stormed into the hard nosed arena of professional design and has possibly cut itself a permanent niche, rather than being perceived as just a passing fad.