scholarly journals Assessment of Soil-Structure Interaction in Seismic Bridge Pier Analysis Using Force and Displacement Based Approaches

2015 ◽  
Vol 10 (2) ◽  
pp. 113-126
Author(s):  
R N P Singh ◽  
Hemant Kumar Vinayak
Keyword(s):  
Soil Structure ◽  
Seismic Analysis ◽  
Soft Soil ◽  
Bridge Pier ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Structure Interaction ◽  
Capacity Spectrum ◽  
Fixed Base ◽  
Displacement Based

Abstract The seismic analysis carried out assuming foundation to be perfectly rigid and bonded to the soil underneath is far from truth and therefore, the soil-structure interaction effect on the dynamic behavior of the bridge pier should be considered. The assessment of soil-structure effect on the design force generated has been estimated using Force based, Capacity Spectrum and Direct Displacement based methods considering fixed and flexible foundations. For this purpose a single cantilever bridge pier of constant diameter with varying heights has been considered for the analysis in different type of soils and earthquake zones. The study has revealed that soil-Structure Interaction index is negative in some cases, especially in soft soil, implying base shear demand being greater than that of fixed base contrary to the traditional views.

scholarly journals Soil-pile-structure interaction effects on high-rise building under seismic shaking

2019 ◽  
Vol 2 (1) ◽  
pp. 153-164
Author(s):  
Umesh Jung Thapa ◽  
Ramesh Karki
Keyword(s):  
Soil Structure ◽  
Seismic Analysis ◽  
Time History ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Structure Interaction ◽  
High Rise ◽  
High Rise Building ◽  
History Analysis ◽  
Fixed Base

In this paper, study of the response (base shear, time period, storey drift, storey displacement) of a structure is done for the tall building including basement with fixed base and with pile foundation considering Soil Structure Interaction (SSI). Finite element based program ETABS2016 v16.1.0 is used for the analysis of the superstructure. Seismic analysis is done to get the dynamic response of superstructure for two types of model,one model is with fixed baseand second is Model with Winkler spring for Chhaya Center, Thamel, a high rise building with 14 story including double basements. Itisobserved with the consideration of Soil Structure Interaction (SSI). The soil is replaced by spring and assigned at joints. El Centro earthquake (1940) is used for time history analysis. The response obtained due to SSI effect is compared with fixed based model. Results of analysis presented include the comparison of natural periods, base shears, displacements and overturning moment. It is observed that the natural periods increase and the base shears decrease as the base become more flexible.

scholarly journals Effect of Soil-Structure Interaction on the Seismic Response of Existing Low and Mid-Rise RC Buildings

2020 ◽  
Vol 10 (23) ◽  
pp. 8357
Author(s):  
Ibrahim Oz ◽  
Sevket Murat Senel ◽  
Mehmet Palanci ◽  
Ali Kalkan
Keyword(s):  
Seismic Response ◽  
Seismic Performance ◽  
Soil Structure ◽  
Soft Soil ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Existing Buildings ◽  
Structure Interaction ◽  
Fixed Base ◽  
New Buildings

Reconnaissance studies performed after destructive earthquakes have shown that seismic performance of existing buildings, especially constructed on weak soils, is significantly low. This situation implies the negative effects of soil-structure interaction on the seismic performance of buildings. In order to investigate these effects, 40 existing buildings from Turkey were selected and nonlinear models were constructed by considering fixed-base and stiff, moderate and soft soil conditions. Buildings designed before and after Turkish Earthquake code of 1998 were grouped as old and new buildings, respectively. Different soil conditions classified according to shear wave velocities were reflected by using substructure method. Inelastic deformation demands were obtained by using nonlinear time history analysis and 20 real acceleration records selected from major earthquakes were used. The results have shown that soil-structure interaction, especially in soft soil cases, significantly affects the seismic response of old buildings. The most significant increase in drift demands occurred in first stories and the results corresponding to fixed-base, stiff and moderate cases are closer to each other with respect to soft soil cases. Distribution of results has indicated that effect of soil-structure interaction on the seismic performance of new buildings is limited with respect to old buildings.

Seismic Response of Multistoried Building with Different Foundations Considering Interaction Effects

2018 ◽  
Vol 877 ◽  
pp. 276-281
Author(s):  
Shreya Sitakant Shetgaonkar ◽  
Purnanand Savoikar
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Response Spectrum ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Foundation Soil ◽  
Soil Medium ◽  
Structure Interaction ◽  
Raft Foundation ◽  
Fixed Base

Current seismic design practice assumes the base of the building to be fixed and does not consider the flexibility of foundation and soil. This assumption is realistic only when the structure is founded on solid rock or when the relative stiffness of the foundation soil compared to the superstructure is high. Whereas, in reality due to natural ability of soil to deform, supporting soil medium modifies the response of the structure during earthquake to some extent. In this work the effect of soil structure interaction on seismic response of building resting on different types of foundation was studied. Present work aims to study the effect of soil structure interaction on seismic response of building resting on fixed base, pile foundation, raft foundation and combined pile-raft foundation. G+9 RCC building is analyzed for earthquake loads considered in zone III by response spectrum method and storey displacement and base shear force of building by considering and without considering SSI effect is found out by using MIDAS GEN software.

scholarly journals Seismic bridge pier analysis for pile foundation by force and displacement based approaches

2015 ◽  
Vol 13 (2) ◽  
pp. 155-166
Author(s):  
NP.R. Singh ◽  
Hemant Vinayak
Keyword(s):  
Pile Foundation ◽  
Seismic Analysis ◽  
Slenderness Ratio ◽  
Soft Soil ◽  
Time History ◽  
Bridge Pier ◽  
Base Shear ◽  
Displacement Based ◽  
Shear Demand ◽  
Analytical Approaches

Seismic analysis of bridge pier supported on pile foundation requires consideration of soil-pile-structure (kinematic and inertial) interactions. This paper presents the design forces generated for bridge piers with varying height and constant diameter for medium and soft soils in earthquake probability zones considering contribution of soil-pile-structure interactions by developed analytical approaches. The results have shown that the difference in base shear demand between force based and displacement based approach and that between capacity spectrum and displacement based method in general decreases with the increase in slenderness ratio of the pier. The base shear demand by non-linear time history analysis has been found to be much higher compared to that by other methods. The relationship between height and pier cross-section has been developed for different soils and seismic zones such that the base shear demands by force based and displacement based method are of the same order. The overall value of the slenderness ratio works out to be such that failure of the pile shall be as a short column for both medium and soft soil.

scholarly journals Comparative Study of Soil Structure Interaction Analysis of Building on Clayey and Sandy Soil

2021 ◽  
Vol 9 (9) ◽  
pp. 57-65
Author(s):  
Payal Jain
Keyword(s):  
Soil Structure ◽  
Clay Soil ◽  
Seismic Analysis ◽  
Soil Structure Interaction ◽  
Base System ◽  
Base Shear ◽  
Structure Interaction ◽  
Time Period ◽  
Natural Time ◽  
Flexible Base

Abstract: Present days the analysis of structure with seismic design is more popular. because the first priority of the engineer is effective and durable structure. There are two type of base system first is rigid and second is flexible. In case of flexible base structure, only seismic analysis is not give very effective results. In this condition the SSI effect is more significant and give effective results for flexible base system. The term Soil Structure Interaction (SSI) means interaction between soil to the substructure. This effect give more accurate results after consider in the seismic analysis. If a structure is design according to the seismic analysis with SSI effect than structure could get more durability and safety against earthquake as compare to seismic analysis without SSI effect condition. So the SSI effect can change response of the seismic very significantly. The present study aim is based on seismic analysis of building with Soil Structure Interaction effect on two different soil. A frame rectangular building of G+6 storey has analyzed for flexible base simulating sand and clay soil conditions The software is used SAP2000. Raft foundation has been modeled also. Analysis is made with the response spectrum of IS 1893 2016 code. Seismic response of SSI analysis results are compare in terms of lateral storey displacement, base shear and modal behavior of natural time period on different type of soil ( clay and sand). and conclude that the lateral storey displacement, base shear and natural time period values in SSI analysis with sand soil is maximum as compare to clay soil.

scholarly journals Revisions to Soil-Structure Interaction Procedures in NEHRP Design Provisions

2003 ◽  
Vol 19 (3) ◽  
pp. 677-696 ◽  
Author(s):  
Jonathan P. Stewart ◽  
Seunghyun Kim ◽  
Jacobo Bielak ◽  
Ricardo Dobry ◽  
Maurice S. Power
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Damping Ratio ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Structure Interaction ◽  
Fixed Base ◽  
Flexible Base ◽  
New Buildings ◽  
Base Structure

The NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures have contained procedures for soil-structure interaction analysis that were originally developed between 1975 and 1977 by the Applied Technology Council Committee on Soil-Structure Interaction (ATC3 Committee 2C). These procedures affect the analysis of seismic demand in structures by modifying the base shear for a fixed-base structure to that for a flexible-base structure with a longer fundamental mode period and a different (usually larger) system damping ratio. In the 2000 NEHRP Provisions and Commentary, several changes were made to these procedures that affect the analysis of foundation stiffness, and in turn affect the SSI adjustment to base shear. In this paper, SSI analysis procedures in the pre-2000 and 2000 NEHRP Provisions are examined relative to a database of “observed” SSI effects previously evaluated using system identification analyses. Through this calibration exercise and focused numerical analyses, we discuss the motivation and justification for the modifications to the NEHRP SSI analysis procedures.

scholarly journals Investigation of Soil Structure Interaction and Wall Flexibility Effects on Natural Sloshing Frequency of Vessels

2017 ◽  
Vol 3 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Pouyan Abbasi Maedeh ◽  
Ali Ghanbari ◽  
Wei Wu
Keyword(s):  
Natural Frequency ◽  
Soil Structure ◽  
Direct Method ◽  
Soft Soil ◽  
Soil Structure Interaction ◽  
International Code ◽  
Structure Interaction ◽  
Wall Flexibility ◽  
Sloshing Frequency ◽  
Fixed Base

The main purpose of this study is to establish the effects of vessel walls flexibility on its natural sloshing frequency considering soil-structure-fluid interaction theory. Furthermore, two new efficiently relations to find both of wall flexibility and soil-structure interaction effects on natural frequency are developed. Regarding the aim of current study three different conditions of elevated tanks are applied. Fixed base condition with an emphasis on recommendations of international code ACI-350, analytical FSSI regarding equivalent mass spring method, and the numerical direct method regarding theory of finite element are taken into consideration. Results indicate that there is no significant effect of walls flexibility on natural sloshing frequency regarding fixed base assumptions of vessels. On the contrary, significant effects of wall flexibility are achieved considering SSI theory. Results of international code ACI-350 show that, the international codes assumptions have imprecise estimations of natural sloshing frequency in the range of hard to very soft soil categories.  On the other hand, it is observed that the wall flexibility has a more highlighted effect on natural frequency in soft soils rather than soil-structure interaction. The significance of wall flexibility effect on natural frequency is more than that of SSI considering soil softening.

scholarly journals Seismic Analysis of Low-Rise Self-Centering Prestressed Concrete Frames considering Soil-Structure Interaction

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liang-Long Song ◽  
Tong Guo ◽  
Xin Shi
Keyword(s):  
Prestressed Concrete ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Nonlinear Dynamic Analysis ◽  
Soil Structure Interaction ◽  
Rc Frame ◽  
Base Shear ◽  
Concrete Frames ◽  
Structure Interaction ◽  
Flexible Foundations

In this study, the seismic behavior of low-rise self-centering (SC) prestressed concrete frames considering soil-structure interaction (SSI) is presented. For this purpose, a typical 4-story SC concrete frame, with and without flexible foundations, is analyzed through nonlinear dynamic analysis. Ground motion sets with two hazard levels are selected for analysis. A conventional reinforced concrete (RC) frame is also studied, and the structural demands of the RC and SC frames are compared in terms of peak and residual drifts, base shear, residual settlement, and rotation of foundation. The analysis results show that considering soil-structure interaction generally increases the peak and residual drift demands and reduces the base shear and connection rotation demands when compared to fixed base conditions. For the cases with and without flexible foundations, the SC frame is found to have comparable peak story drifts with the RC frame and have the inherent potential of significantly reducing the residual drifts. The seismic analysis results of the frames with flexible bases show that the RC and SC frames can experience foundation damage due to excessive residual foundation rotations after the maximum considered earthquake (MCE).

Free Vibration Analysis of Building Considering Soil Structure Interaction

2016 ◽  
Vol 857 ◽  
pp. 125-130 ◽  
Author(s):  
Thaiba T. Beegam ◽  
Tissa Sebastian
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Soft Soil ◽  
Free Vibration Analysis ◽  
Soil Structure Interaction ◽  
Soil Stiffness ◽  
Structure Interaction ◽  
Winkler Model ◽  
Fixed Base ◽  
Flexible Base

Modeling and design of foundation are always done without considering the effect of stiffness of the soil. In the conventional non-interaction analysis of building frame settlements are calculated without considering the influence of the structural stiffness. Therefore a modeling and interaction analysis of soil structure interaction will help to find soil stiffness and effects of soil structure interaction on structure. In this paper, soil structure interaction analysis of a symmetric space frame of 2 bays in both x and y direction are assessed with SAP 2000 software. The frame is modeled with different storey resting on raft foundation with fixed base and flexible base. Three types of soil, i.e. hard, medium, and soft soil are used for Soil Structure Interaction (SSI) study. MODAL analysis is carried out to illustrate the effects of soil-raft-structure interaction on the response of structures. The Soil is considered as Winkler model and elastic continuum model. The developed methodology is validated with results available in the literature. The effects of SSI on frequency of modal are studied. The comparison is carried out the frame with different base conditions.The frequency of the building was found to be decreased when SSI was considered.

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