Investigation of Soil-Structure Interaction and Higher-Mode Effects on Dynamic Response of Base-Isolated Structure Founded on Half Space

2013 ◽  
Author(s):  
C. S. Tsai ◽  
H. C. Su
Keyword(s):  
Closed Form ◽  
Soil Structure ◽  
Dynamic Responses ◽  
Soil Structure Interaction ◽  
Entire System ◽  
Higher Mode Effects ◽  
Closed Form Solutions ◽  
Structure Interaction ◽  
Mode Effects ◽  
Isolated Structures

This paper attempts to investigate the effects of soil-structure interaction (SSI) and higher modes on the dynamic responses of base-isolated structures through closed-form solutions for a superstructure, seismic isolator, and soil system under various conditions, comprising the cases of rigid and half-space foundations. The proposed system considers continuum media for both the superstructure and soil foundation, which can take the effects of higher modes into account, along with a discontinuous layer with a governing equation that interprets the mechanical behavior of the base-isolation system. Then, the closed-form solutions in terms of well-known frequency and impedance ratios under various conditions of soil foundations were obtained through rigorous mathematical derivations and validations by collapsing the entire system to a single degree-of-freedom system in structural dynamics and well-known cases of wave propagation in elastic solids. The closed-form solutions derived in this study explicitly revealed the characteristics of the SSI and higher mode effects in influencing the seismic behavior of base-isolated structures. Furthermore, the SSI effects on the dynamic responses of the entire system were extensively evaluated. The conclusive results of this paper will be useful for understanding the SSI and higher mode effects on the dynamic responses of base-isolated structures.

Effects of Soil-Structure Interaction, Damping and Higher Modes on the Response of a Mid-Story-Isolated Structure Founded on Multiple Soil Layers

2014 ◽  
Author(s):  
Chong-Shien Tsai ◽  
Hui-Chen Su
Keyword(s):  
Soil Structure ◽  
Mechanical Impedance ◽  
Soil Structure Interaction ◽  
Entire System ◽  
Soil Layers ◽  
Higher Modes ◽  
Closed Form Solutions ◽  
Structure Interaction ◽  
Fixed Base ◽  
Beam Type

This paper focuses on investigating the effects of soil-structure interaction (SSI), higher modes, and damping on the response of a mid-story-isolated structure founded on multiple soil layers overlying bedrock. Closed-form solutions were obtained for the entire system, which consists of a shear beam type superstructure, seismic isolator, and multiple soil layers overlying bedrock, while subjected to ground motion. The proposed formulations simplify the problem in terms of well-known frequency and mechanical impedance ratios that can take into account the effects of SSI, higher modes, and damping in the entire system, and be capable of explicitly interpreting the major dynamic behavior of a mid-story-isolated structure interacting with the multiple soil layers overlying bed rock. The SSI effects on the dynamic response of a mid-story-isolated structure as a result of multiple soil layers overlying bedrock were extensively investigated through a series of parametric studies and physically explained by virtue of derived formulations. In addition, the results of numerical exercises show that higher damping provided by the isolator may provoke higher mode response of the superstructure; that the lower structure below the isolator may have significantly larger deformations compared to those of the upper structure above the isolator; and that isolator displacements may be amplified by the SSI effects while compared to those of mid-story-isolated structures with fixed-base.

Role of Soil-Structure Interaction in Base-Isolated Structures Founded on Soil Stratum Overlying Half Space

2013 ◽  
Author(s):  
C. S. Tsai ◽  
H. C. Su
Keyword(s):  
Half Space ◽  
Soil Structure ◽  
Soil Layer ◽  
Dynamic Responses ◽  
Soil Structure Interaction ◽  
Higher Modes ◽  
Soil Stratum ◽  
Structure Interaction ◽  
Isolated Structures

This paper attempts to assess the role of soil-structure interaction (SSI) and higher modes in base-isolated structures founded on a soil layer overlying a half space. Closed form solutions for a system that includes a superstructure, seismic isolator and soil stratum overlying a half space have been obtained. The derived formulations considering the effects of SSI and higher modes in terms of well-known frequency and impedance ratios can explicitly interpret the dynamic behavior of a base isolated structure founded on soil stratum overlying a half space. Furthermore, the SSI effects on dynamic responses of isolated structures founded on soil stratum overlying a half space were extensively investigated. The conclusions drawn by this study provide considerable information for comprehending the SSI and higher mode effects on the dynamic responses of isolated-structures especially for those founded on soil stratum overlying a half space.

scholarly journals Effects of soil-structure interaction on base-isolated structures

2019 ◽  
Vol 357 ◽  
pp. 012031
Author(s):  
M. A. Aden ◽  
Alyaa A. Al-Attar ◽  
F. Hejazi ◽  
M. Dalili ◽  
Nima Ostovar
Keyword(s):  
Soil Structure ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Isolated Structures

Effects of Soil-Structure Interaction on the Response of a Structure With Tuned Mass Dampers

2015 ◽  
Author(s):  
Chong-Shien Tsai ◽  
Hui-Chen Chen
Keyword(s):  
Soil Structure ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Soil Structure Interaction ◽  
Entire System ◽  
Mass Ratio ◽  
Tuned Mass Dampers ◽  
Soil Layers ◽  
Structure Interaction ◽  
Multiple Tuned Mass Dampers

This paper aims at examining the effects of soil-structure interaction (SSI) on the response of a structure which is equipped with multiple tuned mass dampers (MTMD) and founded on multiple soil layers overlying bedrock. Closed-form solutions have been obtained for the entire system, which consists of a shear beam type superstructure, multiple tuned mass dampers, and multiple soil layers overlying bedrock, while subjected to ground motion. The proposed formulations simplify the problem in terms of well-known frequency ratios, mechanical impedance and mass ratio, which can take into account the effects of SSI, mass ratio of the MTMD at each excitation frequency and damping ratio in the entire system. These formulations are capable of explicitly interpreting the major dynamic behavior of a structure equipped with multiple tuned mass dampers and interacting with the multiple soil layers overlying bed rock. The SSI effects on the dynamic response of a tuned-mass-damped structure as a result of multiple soil layers overlying bedrock were extensively investigated through a series of parametric studies.

Simplified Soil–Structure Interaction Analysis for High-Tech Industrial Buildings Subjected to Forced Vibrations

2015 ◽  
Vol 15 (01) ◽  
pp. 1450031 ◽  
Author(s):  
Shi-Shuenn Chen ◽  
Jun-Yang Shi
Keyword(s):  
Soil Structure ◽  
Interaction Analysis ◽  
Dynamic Responses ◽  
Soil Structure Interaction ◽  
High Tech ◽  
System Response ◽  
Soil System ◽  
Structure Interaction ◽  
Industrial Buildings ◽  
Design Values

To implement a safe and reliable design for high-tech industrial buildings, the system response should be accurate enough to include the effect of soil–structure interaction (SSI). This study proposed a simplified building–soil system to analyze the dynamic responses, using parameters that are representative of the practical design values for typical semiconductor fab structures in Taiwan. The responses of the simplified building–soil system subjected to dynamic horizontal loadings are verified in the frequency domain and time domain. The dynamic responses of the simplified building–soil system are found to agree very well with those of the complete system obtained by the half-space theory and by the numerical analysis program. It is shown that the proposed simplified system can effectively analyze the coupled SSI effects in the translational and rotational directions. It is also found that the structural responses may deviate significantly by neglecting the coupling of horizontal and rocking motions as the building has a deeper embedded foundation and a stiffer upper structure. The proposed method can be applied to the vibration analysis of high-tech industrial buildings subjected to dynamic loadings.

The Influence of Mexico City Soils on the Seismic Performance of Friction Damped and Base Isolated Structures

1990 ◽  
Vol 6 (2) ◽  
pp. 335-352 ◽  
Author(s):  
A. Filiatrault ◽  
S. Cherry ◽  
P. M. Byrne
Keyword(s):  
Mexico City ◽  
Seismic Performance ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Friction Damping ◽  
Framed Structures ◽  
Structure Interaction ◽  
High Rise ◽  
Isolated Structures ◽  
Base Isolators

The seismic performance of hypothetical low and high-rise steel framed structures founded on both soft and stiff soils in Mexico City and equipped with (i) friction damping devices, (ii) base isolators and (iii) a combination of base isolators and friction damping devices is compared. The response of the three structural systems, including soil- structure interaction, is examined for two specific sites in Mexico City: the stiff hills zone and the soft lake bed zone. The results of the study show that although soil-structure interaction can be beneficial for some base isolated structures, friction damping alone provides a more consistent way of protecting structures in Mexico City against earthquakes.

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