scholarly journals Critical Analysis of Nonlinear Base-Isolated Building Considering Soil–Structure Interaction under Impulsive and Long-Duration Ground Motions

Geotechnics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 76-94
Author(s):  
Hiroki Akehashi ◽  
Izuru Takewaki
Keyword(s):  
Soil Structure ◽  
Base Isolation ◽  
Ground Motions ◽  
Time History ◽  
Sine Wave ◽  
Soil Structure Interaction ◽  
Input Energy ◽  
Structure Interaction ◽  
Long Duration ◽  
Critical Responses

Critical responses are investigated for nonlinear base-isolated buildings considering soil–structure interaction under near-fault ground motions and long-duration ground motions. A double impulse and a multi impulse are employed to simulate the nonlinear critical responses of the models under such ground motions. The base-isolation story is assumed to consist of lead rubber bearings and to have a bilinear force–deformation relation. Two types of critical timings for a MDOF building model supported by a swaying-rocking spring-dashpot system are derived: (1) the timing that maximizes the total input energy to the whole system and (2) the timing that maximizes the instantaneous input energy to the base-isolated building excluding the swaying-rocking system. These two types of critical timings are compared through numerical examples. Finally, time-history response analyses were conducted under the critical double impulse, the corresponding one-cycle sine wave, and the critical multi impulse. The effect of the soil–structure interaction on the maximum responses of the nonlinear base-isolated building is clarified.

Evaluation of ATC Requirements for Soil-Structure Interaction Using Data from the 3 March 1985 Chile Earthquake

1990 ◽  
Vol 6 (3) ◽  
pp. 593-611 ◽  
Author(s):  
John W. Wallace ◽  
Jack P. Moehle
Keyword(s):  
Soil Structure ◽  
Ground Motions ◽  
Shear Wall ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Structure Interaction ◽  
Long Duration ◽  
Chile Earthquake ◽  
Using Data ◽  
Available Information

The effect of soil-structure interaction on building responses is investigated using data from the 3 March 1985 Chile earthquake. Four shear wall buildings located in Vin~a del Mar, Chile and subjected to strong, long duration, earthquake ground motions during the 3 March 1985 Chile earthquake are studied. Detailed analyses are conducted on one building using available information on soil properties, measured periods, and recorded ground motions. Based on the detailed study, ATC-3 procedures are used to incorporate soil-structure interaction effects for three additional buildings. The analyses indicate that soil-structure interaction is an important consideration for the stiff shear wall buildings located in Vin~a del Mar, Chile. Reductions in base shear of 10 to 47% were computed; however, roof drift ratios generally were unchanged. For spectra representing US design ground motions (ATC), reductions in base shear are not expected to be as pronounced and roof drift ratios are expected to increase moderately.

scholarly journals Evaluation of Soil-Structure Interaction on the Seismic Response of Liquid Storage Tanks under Earthquake Ground Motions

2016 ◽  
Author(s):  
Mostafa Farajian ◽  
Mohammad Iman Khodakarami ◽  
Denise-Penelope N. Kontoni
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Ground Motions ◽  
Time History ◽  
Soil Structure Interaction ◽  
Storage Tanks ◽  
Structure Interaction ◽  
Earthquake Ground Motions ◽  
Liquid Storage ◽  
Matlab Programming

Soil-structure interaction (SSI) could affect the seismic response of structures. Since liquid storage tanks are vital structures and must continue their operation under severe earthquakes, their seismic behavior should be studied. Accordingly, the seismic response of liquid storage tanks founded on half space soil is scrutinized under different earthquake ground motions. To better comparison, the six considered ground motions are classified based on their pulse like characteristics, into two groups, named far and near fault ground motions. To model the liquid storage tanks, the simplified mass-spring model is used and the liquid is modeled as two lumped masses known as sloshing and impulsive, and the interaction of fluid and structure is considered using two coupled springs and dashpots. The SSI effect, also, is considered using a coupled spring and dashpot. Besides, four types of soils are used to consider wide variety of soil properties. To this end, after deriving the equations of motion, the MATLAB programming is employed to obtain the time history responses. Results show that although the SSI effect leads to decrease the impulsive displacement, overturning moment and normalized base shear, the sloshing (or convective) displacement is not affected by such effects due to its long period.

Seismic Soil-Structure Interaction Design Considerations for Offshore Platforms

2016 ◽  
Author(s):  
Jiun-Yih Chen ◽  
Richard Litton ◽  
Albert Ku ◽  
Ramsay Fraser ◽  
Philippe Jeanjean
Keyword(s):  
Soil Structure ◽  
Ground Motions ◽  
Time History ◽  
Time History Analysis ◽  
Radiation Damping ◽  
Soil Structure Interaction ◽  
Offshore Platforms ◽  
Bending Moments ◽  
Structure Interaction ◽  
History Analysis

Offshore platforms for oil and gas production in seismic regions around the world are often required to be designed for seismic hazards according to International Standards (e.g., ISO 19901-2 [1] and ISO 19902 [2]). This paper discusses three important aspects of the nonlinear dynamic time history analysis commonly used to design for Abnormal Level Earthquakes (ALE) in light of findings from recent centrifuge modeling and numerical simulation of the response of offshore structures under earthquake excitations. First, greater-than-expected ground motion de-amplification has been observed in a recent seismic soil-structure interaction centrifuge program for typical “soft” marine clays with undrained shear strength up to 100 kPa per API RP 2GEO [3]. Second, the current industry practice of using uniform down-pile ground motions in the time history analysis tends to underestimate pile bending moments. Use of depth-varying ground motions is strongly recommended to better characterize pile bending moments. Alternatively, a simplified design approach is proposed to account for the higher bending moments from the use of more realistic depth-varying ground motions. This approach is illustrated with a design example. Lastly, hysteretic and radiation damping in soil-structure interaction is discussed. Modeling of hysteretic damping is achieved using nonlinear elasto-plastic soil springs with unload-reload behavior following Masing’s rule, whereas modeling of radiation damping is achieved using viscous dashpots in a parallel or series arrangement with the axial and lateral soil springs and with dashpot coefficients based on O’Rourke and Dobry [4]. The centrifuge data show that proper modeling of radiation damping is important to accurately predict pile load and settlement.

Seismic Response Analysis of Soil-Structure Interaction on Base Isolation Structure

2013 ◽  
Vol 663 ◽  
pp. 87-91
Author(s):  
Ying Bo Pang
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Soil Structure ◽  
Base Isolation ◽  
Soil Structure Interaction ◽  
Response Analysis ◽  
Analysis Model ◽  
Seismic Response Analysis ◽  
Structure Interaction ◽  
Calculation Results

As an effective way of passive damping, isolation technology has been widely used in all types of building structures. Currently, for its theoretical analysis, it usually follows the rigid foundation assumption and ignores soil-structure interaction, which results in calculation results distortion in conducting seismic response analysis. In this paper, three-dimensional finite element method is used to establish finite element analysis model of large chassis single-tower base isolation structure which considers and do not consider soil-structure interaction. The calculation results show that: after considering soil-structure interaction, the dynamic characteristics of the isolation structure, and seismic response are subject to varying degrees of impact.

Soil-structure interaction at CDMG and USGS accelerograph stations

1989 ◽  
Vol 79 (1) ◽  
pp. 1-14
Author(s):  
C. B. Crouse ◽  
Behnam Hushmand
Keyword(s):  
Soil Structure ◽  
Transfer Functions ◽  
Ground Motions ◽  
Free Field ◽  
Soil Structure Interaction ◽  
Imperial Valley ◽  
Structure Interaction ◽  
Fundamental Frequencies ◽  
Vibration Tests ◽  
40 Hz

Abstract Forced harmonic and impulse-response vibration tests were conducted at several California accelerograph stations operated by the California Division of Mines and Geology (CDMG) and U.S. Geological Survey (USGS) to determine the extent to which soil-structure interaction may be affecting the recorded ground motions. The results of the tests on the foundations comprising USGS Station 6 in the Imperial Valley and CDMG Cholame 1E and Fault Zone 3 stations in the Cholame Valley indicated the presence of highly damped fundamental frequencies between 20 and 40 Hz. However, at the much larger Differential Array station, a masonry-block structure approximately 6 km southwest of Station 6, a moderately damped fundamental frequency of 12 Hz was observed. Approximate transfer functions between earthquake motions recorded at the stations and the free-field motions were computed from the response data obtained from the forced harmonic vibration tests. For the three smaller stations, these functions showed peak amplification factors ranging from 1.25 to 1.4 at frequencies between 20 and 40 Hz. The amplification at smaller frequencies was insignificant. For the Differential Array station, the amplification factor was 1.5 at 12 Hz and was roughly 0.6 for frequencies between 14 and 25 Hz. These results suggest that soil-structure interaction will have little effect on ground motions recorded at the smaller stations provided that most of the energy in these motions is confined to frequencies less than approximately 20 Hz. However, at the Differential Array station, soil-structure interaction probably has had, and will continue to have, a significant influence on the motions recorded at this station.

Effects of Slenderness and Fundamental Frequency on the Dynamic Response of Adjacent Structures

2019 ◽  
Vol 19 (09) ◽  
pp. 1950105
Author(s):  
Gonzalo Barrios ◽  
Vinuka Nanayakkara ◽  
Pramodya De Alwis ◽  
Nawawi Chouw
Keyword(s):  
Dynamic Response ◽  
Fundamental Frequency ◽  
Soil Structure ◽  
Numerical Models ◽  
Ground Motions ◽  
Soil Structure Interaction ◽  
Reference Case ◽  
Maximum Acceleration ◽  
Structure Interaction ◽  
Adjacent Structures

In conventional seismic design, the structure is often assumed to be fixed at the base. However, this assumption does not reflect reality. Furthermore, if the structure has close neighbors, the adjacent structures will alter the response of the structure considered. Investigations on soil–structure interaction and structure–soil–structure interaction have been performed mainly using numerical models. The present work addresses the dynamic response of adjacent single-degree-of-freedom models on a laminar box filled with sand. Impulse loads and simulated ground motions were applied. The standalone condition was also studied as a reference case. Models with different fundamental frequencies and slenderness were considered. Results from the impulse tests showed that the top displacement of the models with an adjacent structure was reduced compared with that of the standalone case. Changes in the fundamental frequency of the models due to the presence of an adjacent model were also observed. Results from ground motions showed amplification of the maximum acceleration and the top displacement of the models when both structures have a similar fundamental frequency.

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