Browsing by Author "Jayalekshmi, B.R."

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3D soil–structure interaction analyses of annular raft foundation of tall RC chimneys under wind load
(Springer, 2014) Jisha, S.V.; Jayalekshmi, B.R.; Shivashankar, R.
Three dimensional soil–structure interaction (SSI) analyses of tall reinforced concrete chimneys with annular raft foundation subjected to wind loads are presented in this paper. Different ranges of height and slenderness ratios of the chimneys and different ratios of external diameter to thickness of the annular raft were selected for the parametric study. To understand the significance of SSI, four types of soils were considered based on the stiffness. The chimneys were assumed to be located in terrain category two and subjected to a maximum wind speed of 50 m/s as per IS:875 (Part 3)-1987. The alongwind and across-wind loads were computed according to IS:4998 (Part 1)-1992. The linear elastic behavior was assumed for the integrated chimney-foundation-soil system and it was analysed using finite element software ANSYS based on direct method of SSI. The radial and tangential moments and settlement of annular raft foundation were evaluated through SSI analysis and compared with that obtained from conventional method of analysis as per IS:11089-1984, assuming foundation system is rigid. From the analysis, it is concluded that the SSI analysis results in higher radial moments and lesser tangential moments as compared to conventional method. All these variations depend on the geometric properties of chimney and annular raft foundations. © Indian Geotechnical Society 2013.
A Comparative Study of Data-Driven Models for Shear Strength Prediction of FRP-RC Beam Using Machine Learning Techniques
(Springer Science and Business Media Deutschland GmbH, 2024) Jangid, M.S.; Jayalekshmi, B.R.
Nowadays machine learning techniques are effectively used as a means of resolving issues in civil and structural engineering. Accurately evaluating the shear strength of a reinforced concrete beam with fibre reinforced polymer (FRP) is crucial to ensure a secure design and effectively assess its performance. However, the accuracy of the predictions made by current shear models is generally constrained by the use of a limitedÂ database and complex parameters. The aim of this study is to create a model based on machine learning techniques that can predict the shear strength of reinforced concrete beams containing fibre reinforced polymer bars, both with and without stirrups, by utilizing data-driven approaches. A comprehensive database of 491 shear strength tests on FRP beams was collected from the public literature for developing frameworkâ€™s training and testing sets. In order to prepare the data for machine learning algorithms, exploratory data analysis (EDA) has been carried out to investigate the correlation and identify collinearity between several independent parameters. Further, different models for linear regression, decision tree regression, random forest regression, gradient boost, and XGBoost have been developed for prediction of shear strength based on twelve different independent parameters and dependent output parameters. Root mean square error (RMSE), R2 score, and mean absolute error (MAE) are used to check the performance of all the models, and the best model is chosen for forecasting the shear strength of FRP reinforced concrete beam. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
A Comparative Study on Dynamic Response of Buildings Resting on Coir and Rubber mat Reinforced Soil Bed
(Institute of Physics, 2023) Sreya, M.V.; Jayalekshmi, B.R.; Venkataramana, K.
Geotechnical seismic isolation has emerged as an efficient technique for mitigating the severe effects of earthquakes by providing smooth synthetic liners beneath foundations or between soil layers for dissipating seismic energy through sliding. This study investigates the efficacy of using a rubber mat and a natural coir mat as reinforcement materials within the soil to act as a seismic soil-isolation medium. A three-dimensional finite element simulation of five-storey buildings resting on raft foundations in soft soil with and without the soil-isolation mechanism has been performed. The reinforced soil-structure system was exposed to two different earthquake motions, such as the ground motions corresponding to the elastic design spectrum for Zone III as per the Indian standard code (IS 1893 (Part 1): 2016) and the Northridge earthquake (1994). The proposed study deals with the analysis of dynamic responses of buildings when the soil is reinforced with a coir mat and rubber mat under earthquake motions. The findings show that the seismic responses of low-rise buildings are significantly reduced by a novel technique proposed in this work to reinforce the soil with isolation materials in their mat form to reduce the seismic responses under earthquake loads. Â© Published under licence by IOP Publishing Ltd.
A Numerical Study on the Shear Strength of Pervious Concrete Column in Weak Ground
(Southeast Asian Geotechnical Society, 2022) Rashma, R.S.V.; Jayalekshmi, B.R.; Shivashankar, R.
In this study, the response of pervious concrete column-treated ground under shear loading is examined by employing a series of numerical analyses. The shear behaviour of pervious concrete column-treated ground is compared with stone column-treated ground and weak ground. Two types of analyses were carried out to assess shear strength of the composite ground. Conventional direct shear test model and large shear test models were evaluated using ABAQUS software. The pervious concrete column-treated ground is observed to have greater shear strength than the mere stone column-treated ground. The lateral deflection pattern of the pervious concrete column is also noticed to be very much lesser than conventional stone columns under static shear loading. The overall shear performance of the pervious concrete column-treated ground is found to be improved than the typical stone column-treated ground. © 2022, Southeast Asian Geotechnical Society. All rights reserved.
A Review on Behavior of Piled Raft Foundations Under Various Loads
(Springer Science and Business Media Deutschland GmbH, 2022) Amalu, P.A.; Jayalekshmi, B.R.
Piled raft foundations are a combined system of deep foundation and shallow foundation. In this type of foundation systems, the pile footings are provided beneath a raft or mat footing. Thus, the piled raft foundations can be constructed either by providing raft foundation connected to the pile footings or by providing a cushion layer between raft and pile footings. The first type of piled raft foundation is generally termed as connected piled raft foundations, and the latter piled raft foundations. Piled raft foundations is termed as disconnected can be subjected to different types of loadings, like vertical and inclined loading depending on the type of superstructure, lateral loading induced by earth pressure as well as seismic loads and moments induced by the eccentricity in loadings. Numerous studies have been conducted on the behavior of piled raft foundations under independent and combined effects of these loadings. This article aims to summarize these literature works to review the behavior of piled raft foundations under static and dynamic loadings acting in different directions. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
A Study on Effect of Fluid on the Modal Characteristics of Ground Supported Water Tanks
(IOP Publishing Ltd custserv@iop.org, 2020) Anagha, B.V.; Nimisha, P.; Jayalekshmi, B.R.
Liquid storage tanks are one of the essential lifeline structures which should function even after natural disasters. Water tanks in particular are essential for proper supply of water in the affected areas and for fire-fighting purposes. Sloshing is an important phenomenon occurring in partially filled tank with free surface. It can cause violent liquid motions that can cause instability in carrier-vessel and structural damage in the tank walls. To maintain the structural integrity of the carrier vessels, modal characteristics should be known as the impact of sloshing will increase when the excitation frequency matches with the natural frequency of container and result in resonant condition. This study investigates the modal characteristics such as natural frequency, mode shapes of square tank by 3-D finite element method using ANSYS 2019 R1software. The effect of impulsive and convective frequency of tanks with different fill levels and different boundary conditions are considered. Â© Published under licence by IOP Publishing Ltd.
A Study on Settlement Variation in Piled Raft Foundation Under Seismic Loads
(Springer Science and Business Media Deutschland GmbH, 2022) Krishna, S.V.; Jayalekshmi, B.R.
Piled raft foundations are usually used to transmit the loads from superstructure to the soil beneath the structure having low or medium bearing capacity to hard or rock strata with a higher bearing capacity and stiffness. This paper investigates the influence of the length and stiffness of the piles on the performance of the raft foundation. For this, a ten storey moment-resisting frame resting on piled raft foundation with different pile length was simulated numerically. Three-dimensional numerical model of the soil medium, piles, raft and the structural elements were created in ANSYS software. Four bay 10 storey building frames having 3Â m bay length and storey height of 3Â m is with different pile configurations are considered for the study. The column size of 0.5Â m Ã— 0.5Â m and beam size of 0.3Â m Ã— 0.45Â m were taken for frames. The dimension of the raft foundation is 14mx14mx1m. This study mainly focuses on the vertical settlement of the raft at various locations along the length of the raft foundation when subjected to El Centro earthquake and time history corresponding to response spectrum given in IS 1893 code. Study was conducted on five types of pile configuration based on pile length. It was found that the settlement at the edges of the raft is minimum for model M1 which is having longest peripheral pile and minimum settlement at the centre is observed for model M5 which has longer central pile compared to peripheral piles. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
A Study on the Behavior of Piled Raft Foundation Under Seismic Loading
(Springer Science and Business Media Deutschland GmbH, 2023) Reddy, D.M.M.; Krishna, S.V.; Jayalekshmi, B.R.
High rise buildings require strong foundations which should bear heavy loads with less settlement. There has been an increase in the use of combined piled raft foundations because of the effectiveness in bearing heavy loads with comparatively very less settlements. This paper presents the variation in roof displacement, bending moment and shear force of a 10-storey building frame resting on a piled raft foundation having various pile stiffness under earthquake excitations corresponding to El Centro and Loma Prieta earthquakes. Column and beam dimensions of the frame are taken as 0.5 m × 0.5 m and 0.3 m × 0.45 m. The length of the pile is taken as 10 m and the diameter is taken for a range of 0.6 m to 1.2 m. Vertical loading condition is varied by considering different mass at each floor level. Not much variation in the roof displacement is found with a change in the pile stiffness. Variation in the response has been observed for different vertical loading and changes in the pile stiffness. The response of the structure for the two earthquake motions is entirely different. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
A Study on the Seismic Behaviour of Embankments with Pile Supports and Basal Geogrid
(Springer, 2020) Patel, R.M.; Jayalekshmi, B.R.; Shivashankar, R.
For constructing the roads on soft grounds, basal geogrid-reinforced pile-supported embankments are a suitable solution over other conventional ground improvement techniques like preloading, embankment slope flattening, removing and replacing the soft soil, etc. Many studies are available on these basal geogrid-reinforced piled embankments to understand their behaviour under static loading conditions. But it is necessary to understand the behaviour of these geogrid-reinforced piled embankments under seismic excitations. Hence, finite element analysis of three-dimensional models of embankment having crest width of 20 m, height above ground of 6 m, with side slopes of 1V:1.5H consisting of pulverized fuel ash, overlying soft marine clay of 28 m thickness is carried out under seismic excitations corresponding to Zone III (IS:1893). Soft marine clay layer is improved by the addition of piles arranged in square grid pattern with 5.75% area replacement ratio. Geogrid with a tensile modulus of 4600 kN/m is used as the basal reinforcement. Initially, the embankment is analyzed without geogrid reinforcement and pile supports. Then, it is analyzed with (i) Basal geogrid (ii) With pile supports (iii) With basal geogrid and pile supports. The influence of various parameters of the embankment on maximum crest displacements, differential settlements at crest, toe horizontal displacements, stresses at pile head and foundation soil between piles and pile bending moment along the depth at peak acceleration are studied. Analysis of results shows that the embankment supported over piles with basal geogrid reinforcement will experience less crest settlements, differential settlements at crest and toe horizontal displacements due to earthquake load. © 2020, Springer Nature Singapore Pte Ltd.
Analysis of Cushion Effects in Unconnected Piled Raft Foundation
(Springer Science and Business Media Deutschland GmbH, 2022) Amalu, P.A.; Jayalekshmi, B.R.
The piled raft foundations are an economical solution as well as a settlement reducer in the construction of high-rise buildings. Unconnected piled raft foundation is an innovative technique where a cushion separates the pile and raft. The cushion takes the load transferred from the raft and safely distributes over the piles beneath. This article analyses the seismic behaviour of connected and unconnected piled raft foundation of a multistorey building using ANSYS software based on the finite element method. An 8Â mÂ Ã—Â 8Â mÂ Ã—Â 1Â m raft and 0.4Â mÂ Ã—Â 0.4Â m square concrete piles with depth of 12Â m resting on a very soft clay stratum were modelled. The soil block of 16Â mÂ Ã—Â 16Â m plan dimension with a depth of 16Â m was provided with transmitting boundaries at all lateral edges with properties corresponding to shear wave velocity of clay (150Â m/s) and was analysed for the response under the ground motion corresponding to El Centro 1940 earthquake. The building load acting on the raft was considered as a uniformly distributed load of 0.2Â MPa. The vertical and lateral displacements at the top of the raft were analysed with cushions having different elastic modulus and thickness. An increase in the elastic modulus of cushion tends to reduce the settlement considerably whereas, a positive correlation was observed between the depth of cushion layer and corresponding settlement. It is evident from the results of the numerical analysis that the stiffness of cushion layer and thickness are two important aspects which determine the displacements of unconnected piled raft systems. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Analysis of Foundation of Tall R/C Chimney Incorporating Flexibility of Soil
(Springer India sanjiv.goswami@springer.co.in, 2017) Jayalekshmi, B.R.; Jisha, S.V.; Shivashankar, R.
Three dimensional Finite Element (FE) analysis was carried out for 100 and 400 m high R/C chimneys having piled annular raft and annular raft foundations considering the flexibility of soil subjected to across-wind load. Stiffness of supporting soil and foundation were varied to evaluate the significance of Soil-Structure Interaction (SSI). The integrated chimney-foundation-soil system was analysed by finite element software ANSYS based on direct method of SSI assuming linear elastic material behaviour. FE analyses were carried out for two cases of SSI namely, (1) chimney with annular raft foundation and (2) chimney with piled annular raft foundation. The responses in raft such as bending moments and settlements were evaluated for both the cases and compared to those obtained from the conventional method of analysis of annular raft foundation. It is found that the responses in raft vary considerably depending on the stiffness of the underlying soil and the stiffness of foundation. Piled raft foundations are better suited for tall chimneys to be constructed in loose or medium sand. © 2017, The Institution of Engineers (India).
Analysis of foundation of tall RC chimney with 3D finite element method
(2014) Jisha, S.V.; Jayalekshmi, B.R.; Shivashankar, R.
3D finite element (FE) analyses were carried out for 100-m and 400-m-high RC chimneys having piled annular raft and annular raft foundations considering the flexibility of soil subjected to across-wind load. Stiffness of supporting soil and foundation were varied to evaluate the significance of SSI. The integrated chimney-foundation-soil system was analysed by finite element software ANSYS based on direct method of SSI assuming linear elastic material behaviour. FE analyses were carried out for two cases of SSI, namely: (1) chimney with annular raft foundation, and (2) chimney with piled annular raft foundation. The responses in raft, such as bending moments and settlements, were evaluated for both cases and compared to those obtained from the conventional method of analysis of annular raft foundation. It is found that the responses in raft depend on the stiffness of the underlying soil and the stiffness of foundation. � ASCE 2014.
Analysis of foundation of tall RC chimney with 3D finite element method
(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2014) Jisha, S.V.; Jayalekshmi, B.R.; Shivashankar, R.
3D finite element (FE) analyses were carried out for 100-m and 400-m-high RC chimneys having piled annular raft and annular raft foundations considering the flexibility of soil subjected to across-wind load. Stiffness of supporting soil and foundation were varied to evaluate the significance of SSI. The integrated chimney-foundation-soil system was analysed by finite element software ANSYS based on direct method of SSI assuming linear elastic material behaviour. FE analyses were carried out for two cases of SSI, namely: (1) chimney with annular raft foundation, and (2) chimney with piled annular raft foundation. The responses in raft, such as bending moments and settlements, were evaluated for both cases and compared to those obtained from the conventional method of analysis of annular raft foundation. It is found that the responses in raft depend on the stiffness of the underlying soil and the stiffness of foundation. Â© ASCE 2014.
Applications of AI in Health Monitoring of Structures in Potential Seismic Areasâ€”A Review
(Springer Science and Business Media Deutschland GmbH, 2022) Ginan, C.P.; Jayalekshmi, B.R.
Artificial Intelligence (AI) can be used to solve complex problems in civil engineering which involve time-consuming and arduous tasks, such that, the hurdles that appear when these works are completed using mere human labour can be completely overcome, by employing various techniques of AI. Furthermore, where testing fails or is hardly possible, AI can suffice the required design. AI can be of its best use when applied to the field of Structural Health Monitoring (SHM), which serves to identify and detect the current state and behaviour of structures. This article outlines the applications of AI in SHM in potential seismic zones. SHM functions in seismically prone areas by evaluating on field, the resistive power of a building against earthquakes and simultaneously it's potent to carry forth the services. The paper studies certain observations from research conducted during past few decades on development of artificial intelligence in SHM technologies in seismically intensive areas, in case of multistorey buildings, bridges, special structures and lifeline structures. The article begins with a brief introduction to artificial intelligence, further, detailing applications of AI in SHM in seismically prone areas. Subsequently, the contemporary applications of AI in the field are reviewed, alongside, the adaptability, sufficiency and potentiality of those methods to overcome the barriers of the conventional methods are discussed. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Development of Effective Baffle Configuration for Slosh Response Control In Liquid Storage Tanks
(National Institute of Technology Karnataka, Surathkal, 2023) P, Nimisha; Jayalekshmi, B.R.; Venkataramana, Katta
The quantification and damping of slosh responses have become important due to the increasing demand for the safety of the liquid tanks under severe external excitations. There is uncertainties in the selection of an effective configuration of the baffle plate as an anti-slosh mechanism. Therefore, the present study focuses on the development of an effective configuration of perforated baffle plate by analysing the slosh responses of the liquid tanks under seismic ground motions and pitch excitations. Initially, modal analysis was carried out to investigate the dynamic characteristics of cylindrical as well as rectangular liquid tanks. Subsequently, nonlinear dynamic analysis under seismic ground motions of different PGA/PGV ratios has been carried out, considering the models of rectangular tanks with and without baffle plates. A detailed parametric study is carried out by considering the effects of the percentage of perforation, inter perforation distance, size of perforations, offset distance of the perforated plate, the distance between the perforated baffle plates, alignment of perforations, and the vertical position of perforated baffle plate on the slosh damping efficiency of liquid tanks. The slosh responses are observed in terms of free surface elevation and hydrodynamic pressure as major response parameters. The parametric study is extended for the response of a small-scale model under pitch excitation as well. Finally, the experimental validation of the developed configuration of the baffle plate is done on the same small-scale model using a shake table test. Modification coefficients for the standard codal expressions are suggested for the accurate estimation of the fundamental impulsive frequency of cylindrical tanks. The frequency values decrease with the installation of baffle plates in the rectangular tanks. The optimum perforation of the baffle plate is in the range of 5% to 17%, considering the responses under convective as well as impulsive conditions that should be selected based on the frequency characteristics of the sloshing liquid and the input motion along with the requirements for weight reduction. The study identified different zones and damping ranges to pilot the positioning of the perforated baffle plate in the liquid tanks. Additionally, a novel ‘zig-zag blocking alignment’ of perforations for the perforated baffle plates to damp the slosh response under both convective and impulsive modes of response, which can be applied even under severe sloshing conditions, has been developed.
Dynamic Response Analysis of Fluid Storage Tanks Using Coupled Acoustic-Structural Approach
(Springer Science and Business Media Deutschland GmbH, 2024) Giridhar, P.; Jogi, P.; Jayalekshmi, B.R.
Industrial fluid storage tanks are exposed to significant damage in earthquakes and cause the destruction of life and property. The seismic response of fixed-supported, three-dimensional rectangular rigid and flexible fluid storage tanks is analyzed using the finite element method. In this study, the fluid storage tanks are examined by utilizing coupled acoustic-structural (CAS) models. The convective displacement behaviors of rectangular liquid tanks are studied numerically under harmonic and earthquake excitations. The tank fluidâ€“structure interaction (FSI) performance is studied by applying CAS methodology. Convective displacement, convective pressure component, impulsive pressure component, and total hydrodynamic pressures are analyzed for square and rectangular liquid storage tanks, and it is found that rectangular fluid storage tanks have more sloshing displacement and impulsive pressure component compared to square liquid storage tanks. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Dynamic response assessment of RC buildings featuring basement storeys integrated with soil-nailed structures
(Elsevier Ltd, 2025) Amrita; Jayalekshmi, B.R.; Shivashankar, R.
The rising demand for high-rise buildings and infrastructure has led to construction on hilly and sloping terrains, necessitating their stabilisation. The area adjacent to a vertical cut, stabilised through the soil nailing technique, presents opportunities for constructing multi-storey buildings. Incorporating basement levels in buildings is also a common practice to maximise the utility of space. This study evaluates the seismic performance of integrated soil-nailed wall-building systems, where the multi-storey building is connected to the soil-nailed structure through a shear wall, termed the Shear wall (SW) system. The effect of providing two basement levels on the seismic response of the integrated SW system is analysed in soft soil conditions, denoted as the SWB system (Shear wall system with basement floors). Finite element analysis of three-dimensional models of these integrated systems is conducted in PLAXIS software. The influence of the frequency content of dynamic excitations on the responses of these structures is assessed using time history data of three different earthquakes, considering various heights of the building. Results indicate that the SWB system provides substantial benefits, including a 35.17 % reduction in seismic building deformation, a 19.23 % reduction in soil-nailed wall acceleration, an 81.66 % reduction in axial nail force and a 54.77 % reduction in inter-storey drift. However, these improvements come with increased lateral earth pressure on the soil-nailed wall, necessitating careful design to ensure optimal seismic performance. These integrated configurations are recommended as suitable for optimum space utilisation in space-constrained urban sites while ensuring structural stability under seismic loading. © 2025 Elsevier Ltd
Dynamic Response of Soil Nailed Wall
(Springer Science and Business Media Deutschland GmbH, 2021) Amrita; Jayalekshmi, B.R.; Shivashankar, R.
Soil nailing is a technique used to stabilize steep cut slopes and to retain excavations. The method consists of inserting nail bars into the ground to stabilize the soil mass. The present study evaluates the dynamic response of a soil nailed wall supporting a vertical cut of height 6Â m. The finite element analysis has been carried out to study the stability and performance of the soil nailed wall using PLAXIS 2D software. The seismic resistance and failure mechanism of the wall are analyzed under the El Centro ground motion. The seismic response variation for different parameters such as angle of inclination of nail and length of nail is studied. The results are observed in terms of maximum lateral displacement, development of maximum tensile force in nails and failure mechanism of soil nailed wall under static and dynamic conditions. The results of the study indicate that the soil nailed structure is an effective method which imparts stability to the retaining system under dynamic conditions. Â© 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Dynamic soil-structure interaction analysis of 300m tall industrial reinforced concrete chimneys on piled raft foundations
(2014) Jisha, S.V.; Jayalekshmi, B.R.; Shivashankar, R.
Soil-structure interaction (SSI) analysis of 300m tall slender industrial reinforced concrete chimneys with piled raft foundation subjected to Elcentro (1940) ground motion is carried out in the present study. The transient analysis of three dimensional chimney-piled raft-soil system was conducted based on direct method of SSI using finite element method. Linear elastic material behaviour was assumed for the chimney, piled raft and soil. Parametric studies were conducted by considering different thickness of raft of piled raft foundation and different soil types to understand the significance of SSI. The time history analysis of the integrated chimney-foundation-soil was carried out with ground motion corresponding to the Imperial Valley earthquake at Elcentro (1940) with a magnitude of 7.0 and peak ground acceleration of 0.319g. The time history of acceleration was applied in the global X direction of the entire soil-structure model. The responses in terms of tangential and radial bending moments in raft, settlement of raft and tip deflection of chimney were investigated. The bending moments in raft of piled raft foundation obtained from SSI analysis were compared with that obtained from conventional analysis. It is found that the response in chimney and raft is considerably high for chimney-piled raft system resting on loose sand and it depends on the characteristics of ground motion also.
Dynamic soil-structure interaction analysis of 300m tall industrial reinforced concrete chimneys on piled raft foundations
(Earthquake Engineering Research Institute, 2014) Jisha, S.V.; Jayalekshmi, B.R.; Shivashankar, R.
Soil-structure interaction (SSI) analysis of 300m tall slender industrial reinforced concrete chimneys with piled raft foundation subjected to Elcentro (1940) ground motion is carried out in the present study. The transient analysis of three dimensional chimney-piled raft-soil system was conducted based on direct method of SSI using finite element method. Linear elastic material behaviour was assumed for the chimney, piled raft and soil. Parametric studies were conducted by considering different thickness of raft of piled raft foundation and different soil types to understand the significance of SSI. The time history analysis of the integrated chimney-foundation-soil was carried out with ground motion corresponding to the Imperial Valley earthquake at Elcentro (1940) with a magnitude of 7.0 and peak ground acceleration of 0.319g. The time history of acceleration was applied in the global X direction of the entire soil-structure model. The responses in terms of tangential and radial bending moments in raft, settlement of raft and tip deflection of chimney were investigated. The bending moments in raft of piled raft foundation obtained from SSI analysis were compared with that obtained from conventional analysis. It is found that the response in chimney and raft is considerably high for chimney-piled raft system resting on loose sand and it depends on the characteristics of ground motion also.