Confirmation of Reduction Effect Due to Tank’s Rocking Behavior and Proposal for a Simplified Evaluation Method of Nonlinear Seismic Response

2003 ◽  
Author(s):  
Satoru Yamaguchi ◽  
Hideyuki Tazuke ◽  
Kazuo Ishida
Keyword(s):  
Nonlinear Analysis ◽  
Seismic Response ◽  
Evaluation Method ◽  
Time History ◽  
Bottom Plate ◽  
Response Factor ◽  
Mass System ◽  
Nonlinear Seismic Response ◽  
Reduction Effect ◽  
Rocking Behavior

Aboveground LNG storage tank consists of inner and outer cylindrical containers. LNG is stored in the inner container made by 9%Ni steel. Anchorages are attached to some tanks in order to prevent bottom plate from excessive uplifting by seismic overturning moment. However tanks without anchorages have some probability that the seismic response factor decreases since the resonance period of tank is lengthened by nonlinear behaviors, for example uplifting of bottom plate (rocking behavior). In this paper, the reduction effect of response factor due to rocking behavior was quantitatively confirmed by 3-dimensional FEM nonlinear analysis and time-history nonlinear analysis that was modeled with single-degree-of-freedom spring-mass system. And a simplified evaluation method that allows easily calculating the reduction effect was proposed. As the result of study, it was proved that this method gave valid and conservative results.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

Seismic Response of Bridge Isolated with Friction Pendulum Systems

2012 ◽  
Vol 256-259 ◽  
pp. 2122-2126
Author(s):  
Chang Feng Wang ◽  
Chun Lin Zhu
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Restoring Force ◽  
Simply Supported ◽  
Long Span ◽  
Steel Truss ◽  
Reduction Effect ◽  
Nonlinear Time History ◽  
Friction Pendulum

Friction pendulum systems are sliding bearing that make use of a spherical concave surface to provide a restoring force and friction force to dissipate earthquakes energy. Seismic response reduction effect of some tall pier and long span simply-supported steel truss girders with FPS is researched by using nonlinear time history analysis method. The results show that seismic response reduction effect is evident for the moment at the bottom of pier and displacement at the top of pier for the tall pier and long span simply-supported steel truss girders.

Nonlinear Seismic Response Analysis of RAC Space Frame Structure

2013 ◽  
Vol 405-408 ◽  
pp. 1046-1050
Author(s):  
Chang Qing Wang
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Material Model ◽  
Element Model ◽  
Shaking Table ◽  
Frame Structure ◽  
Response Analysis ◽  
Nonlinear Seismic Response ◽  
Steel Material ◽  
Dynamic Time

An OpenSees computational platform-based 3-dimentional space RAC finite element model is established for reproducing the seismic response of a 1/4 scaled 6-story, 2-bay and 2-span RAC frame model regular in elevation that was tested on shaking table under a series of one-dimensional base excitations with gradually increasing acceleration amplitudes. The dynamic characteristic parameters of the numerical model, including natural frequencies and vibration modes are captured by performed modal analysis. The acceleration response, the maximum storey displacements and the inter-storey drifts are carefully predicted by performed dynamic time history analysis. Very satisfactory agreement between experimental and analytical results is observed. The numerical simulation verifies that the beam-column element type, the section model, the confined concrete model, the steel material model, and the numerical methods used for the proposed model are reasonable.

Nonlinear Seismic Response Analysis of Canyons in Layered Sites

2013 ◽  
Vol 438-439 ◽  
pp. 1559-1562
Author(s):  
Jian Wen Liang ◽  
Ming Liang Liu
Keyword(s):  
Nonlinear Analysis ◽  
Seismic Response ◽  
Linear Method ◽  
Response Spectra ◽  
Linear Analysis ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Nonlinear Seismic Response ◽  
Transmitting Boundary ◽  
Equivalent Linear Method

This paper presents nonlinear seismic response analysis of canyons in layered sites. The equivalent linear method is used in the dynamic analysis and Lysmer-Kuhlemeyer transmitting boundary is added at the left and right boundaries of the computation region. It is shown through numerical examples that, soil nonlinearity has significant effect on seismic ground motion around canyons. There are differences between seismic response amplitudes in nonlinear analysis and those in linear analysis, but the differences are smaller for observation points inside canyons. There are shifts between response spectra in nonlinear analysis and those in linear analysis, but the differences are much larger for observation points inside canyons.

scholarly journals Effect Mechanism of Connection Joints in Fabricated Station Structures

2021 ◽  
Vol 11 (24) ◽  
pp. 11927
Author(s):  
Huafei He ◽  
Zhaoping Li
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Joint Distribution ◽  
Damage Index ◽  
Time History ◽  
Subway Station ◽  
Bottom Plate ◽  
Relative Deformation ◽  
Damage Degree ◽  
Station Structure

The seismic response of a fabricated subway station is a complex structural connection problem that depends on the mechanical properties of the joints. In order to obtain the optimal joint distribution of a fabricated station structure under earthquake action, three finite element models of a single ring structure of fabricated subway stations assembled with seven, five, and four prefabricated components were proposed. Seismic wave characteristics, peak acceleration, and coupled horizontal and vertical seismic components were considered to study the seismic response of the fabricated subway station structure with different forms of the joint distribution. The dynamic time history method was used to analyze the seismic response in three aspects: structure plastic strain, interlayer relative deformation, and internal force. The damage indexes and residual strength indexes of the joints were offered based on the concrete damage index to evaluate the joints’ damage degree. The results showed that the joints of the vault or bottom plate had little influence on the seismic response of the fabricated station structure. The sidewall joints had the obvious seismic response and the most severe damage under horizontal ground motion or coupled ground motion, which were the weak joints of the fabricated station structure. The existence of vertical ground motion aggravated the damage degree of sidewall joints, making the damage occurrence time of sidewall joints earlier and the damage end time extended. On the premise of meeting the mechanical load and site requirements, an assembly scheme with fewer prefabricated components can be selected.

scholarly journals Reliability-based strength modification factor for seismic design spectra considering structural degradation

2020 ◽  
Author(s):  
Sonia E. Ruiz ◽  
Ali Rodríguez-Castellanos ◽  
Edén Bojórquez ◽  
Miguel A. Orellana ◽  
Afredo Reyes-Salazar
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Mathematical Expression ◽  
Nonlinear Time History Analysis ◽  
Uniform Hazard Spectra ◽  
Structural Degradation ◽  
Design Spectra ◽  
Nonlinear Seismic Response ◽  
Earthquake Resistant Design ◽  
Nonlinear Time History

Abstract. For earthquake resistant design, structural degradation is considered using traditional strength modification factors, which are obtained via the ratio of the nonlinear seismic response of degrading and non-degrading structural single degree of freedom (SDOF) systems. In this paper, with the aim to avoid the nonlinear seismic response to compute strength modification factors, a methodology based on probabilistic seismic hazard analyses (PSHA) is proposed in order to obtain strength modification factors of design spectra which consider structural degradation through the spectral-shape intensity measure INp. PSHA using INp to account for structural degradation, and Sa(T1) which represents the spectral acceleration associated with the fundamental period and does not consider such degradation, are performed. The ratio of the uniform hazard spectra in terms of INp and Sa(T1), that represent the response of degrading and non-degrading systems, provide new strength modification factors without the need to develop nonlinear time history analysis. A mathematical expression is fitted to the ratios that correspond to systems located in different soil types. The expression is validated by comparing the results with those derived from nonlinear time-history analyses of structural systems.

Seismic Response Analysis of Piping Systems With Nonlinear Supports Using Differential Algebraic Equations

2004 ◽  
Vol 126 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Tetsuya Kimura ◽  
Yoshikazu Ohe
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Differential Algebraic Equations ◽  
Response Analysis ◽  
Algebraic Equations ◽  
Seismic Responses ◽  
Seismic Response Analysis ◽  
Nonlinear Seismic Response ◽  
Piping Systems ◽  
Time History Response

Hysteresis elements such as elasto-plastic dampers are important elements for mechanical structures, especially for earthquake-proof structures. When such nonlinear supports are utilized for piping systems, the nonlinearities of the hysteresis elements and the geometrical complexity of the piping systems lead to complicated seismic responses, and thus further studies are required in order to enhance the reliability of the earthquake-proof design. In the seismic response analysis, the method of time history response analysis is widely used. In this paper, a method of nonlinear seismic response analysis for a piping systems using a combination of the FEM and the Differential Algebraic Equations (DAE) is proposed. As it is well known, the DAE is suitable for numerical analysis of time history responses for mechanical structures and machinery elements. According to the advantage of the DAE, the numerical modeling and simulation of a complex piping systems supported by the hysteresis elements can be easily carried out by using the proposed method. In order to verify the usefulness of the method, the time history responses of piping systems supported by a elasto-plastic damper is examined for seismic excitation by using the proposed method. The damper is modeled as a bilinear model. The effects of the second stiffness and the stiffness associated with the plastic deformation of the damper on the seismic responses are investigated using an actually recorded earthquake motion.

scholarly journals Reliability-based strength modification factor for seismic design spectra considering structural degradation

2021 ◽  
Vol 21 (5) ◽  
pp. 1445-1460
Author(s):  
Ali Rodríguez-Castellanos ◽  
Sonia E. Ruiz ◽  
Edén Bojórquez ◽  
Miguel A. Orellana ◽  
Alfredo Reyes-Salazar
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Mathematical Expression ◽  
Nonlinear Time History Analysis ◽  
Uniform Hazard Spectra ◽  
Structural Degradation ◽  
Design Spectra ◽  
Nonlinear Seismic Response ◽  
Earthquake Resistant Design ◽  
Nonlinear Time History

Abstract. For earthquake-resistant design, structural degradation is considered using traditional strength modification factors, which are obtained via the ratio of the nonlinear seismic response of degrading and non-degrading structural single-degree-of-freedom (SDOF) systems. In this paper, with the aim to avoid the nonlinear seismic response to compute strength modification factors, a methodology based on probabilistic seismic hazard analyses (PSHAs), is proposed in order to obtain strength modification factors of design spectra which consider structural degradation through the spectral-shape intensity measure INp. PSHAs using INp to account for structural degradation and Sa(T1), which represents the spectral acceleration associated with the fundamental period and does not consider such degradation, are performed. The ratio of the uniform hazard spectra in terms of INp and Sa(T1), which represent the response of degrading and non-degrading systems, provides new strength modification factors without the need to develop nonlinear time history analysis. A mathematical expression is fitted to the ratios that correspond to systems located in different soil types. The expression is validated by comparing the results with those derived from nonlinear time history analyses of structural systems.

A novel tuned mass-conical spring system for passive vibration control of a variable mass structure

2021 ◽  
pp. 107754632110004
Author(s):  
Sanjukta Chakraborty ◽  
Aparna (Dey) Ghosh ◽  
Samit Ray-Chaudhuri
Keyword(s):  
Variable Mass ◽  
Design Procedure ◽  
Time History ◽  
Tuned Mass Damper ◽  
Water Tank ◽  
Mass System ◽  
Mass Damper ◽  
Linear Spring ◽  
Spring System ◽  
Elevated Water

This article presents the design of a tuned mass damper with a conical spring to enable tuning to the natural frequency of the system at multiple values, as may be convenient in case of a system with fluctuations in the mass. The principle and design procedure of the conical spring in the context of a varying mass system are presented. A passive feedback control mechanism based on a simple pulley-mass system is devised to cater to the multi-tuning requirements. A design example of an elevated water tank with fluctuating water content, subjected to ground excitation, is considered to numerically illustrate the efficiency of such a tuned mass damper associated with the conical spring. The conical spring is designed based on the tuning requirements at different mass conditions of the elevated water tank by satisfying the allowable load bearing capacity of the spring. Comparisons are made with the conventional passive tuned mass damper with a linear spring tuned to the full tank condition. Results from time history analysis reveal that the conical spring-tuned mass damper can be successfully designed to remain tuned and thereby achieve significant response reductions under stiffening conditions of the primary structure, whereas the linear spring-tuned mass damper suffers performance degradation because of detuning, whenever there is any fluctuation in the system mass.

scholarly journals Investigating the Use of Natural and Artificial Records for Prediction of Seismic Response of Regular and Irregular RC Bridges Considering Displacement Directions

2021 ◽  
Vol 11 (3) ◽  
pp. 906
Author(s):  
Payam Tehrani ◽  
Denis Mitchell
Keyword(s):  
Seismic Response ◽  
Radial Displacement ◽  
Time History ◽  
Good Prediction ◽  
3D Analysis ◽  
Combination Rules ◽  
Principal Axes ◽  
Artificial Records ◽  
The Mean ◽  
Irregular Bridges

The seismic responses of continuous multi-span reinforced concrete (RC) bridges were predicted using inelastic time history analyses (ITHA) and incremental dynamic analysis (IDA). Some important issues in ITHA were studied in this research, including: the effects of using artificial and natural records on predictions of the mean seismic demands, effects of displacement directions on predictions of the mean seismic response, the use of 2D analysis with combination rules for prediction of the response obtained using 3D analysis, and prediction of the maximum radial displacement demands compared to the displacements obtained along the principal axes of the bridges. In addition, IDA was conducted and predictions were obtained at different damage states. These issues were investigated for the case of regular and irregular bridges using three different sets of natural and artificial records. The results indicated that the use of natural and artificial records typically resulted in similar predictions for the cases studied. The effect of displacement direction was important in predicting the mean seismic response. It was shown that 2D analyses with the combination rules resulted in good predictions of the radial displacement demands obtained from 3D analyses. The use of artificial records in IDA resulted in good prediction of the median collapse capacity.

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