Experimental study of residual displacements of double concave friction pendulum isolation systems Residual displacements of friction pendulum isolation systems

A comparative study is carried out on the performance of various elastomeric and frictional base isolation (BI) systems in the vibration mitigation of structures subjected to underground blast induced ground motion (BIGM). The parametric sensitivities of the base isolated structures to variations in the design parameters of the isolators are examined for different intensities of blast input. Results indicate that substantial reductions in both the acceleration and displacement responses of the structure can be achieved by the different base isolators. Generally, the Electricite de France (EDF) base isolator produces higher peak response reductions. However, peak bearing displacements are also largest here. The pure friction (P-F), resilient-friction base isolator (R-FBI) and friction pendulum (FP) systems produce lower values of response reductions but peak bearing displacements as well as residual displacements of isolators are also low. The New Zealand (N-Z) system provides good response reductions with a low to moderate value of peak bearing displacement. The present study indicates how a proper selection of the type of BI system with suitable design parameters can mitigate structural vibration due to different intensities of BIGM and restrict the unwanted characteristics of large isolator displacement and its permanent deformation.

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Experimental Study of Friction Pendulum System to Improve the Seismic Capacity of Transformer

Journal of the Earthquake Engineering Society of Korea ◽

10.5000/eesk.2008.12.2.001 ◽

2008 ◽

Vol 12 (2) ◽

pp. 1-8 ◽

Cited By ~ 3

Keyword(s):

Experimental Study ◽

Seismic Capacity ◽

Pendulum System ◽

Friction Pendulum ◽

Friction Pendulum System

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Energy-Based Prediction of the Displacement of DCFP Bearings

Applied Sciences ◽

10.3390/app10155259 ◽

2020 ◽

Vol 10 (15) ◽

pp. 5259

Author(s):

Jiaxi Li ◽

Shoichi Kishiki ◽

Satoshi Yamada ◽

Shinsuke Yamazaki ◽

Atsushi Watanabe ◽

...

Keyword(s):

Prediction Method ◽

Analysis Data ◽

Simplified Model ◽

Design Stage ◽

Response Analysis ◽

Isolation Layer ◽

Constant Friction ◽

Friction Models ◽

Isolation Systems ◽

Friction Pendulum

Isolation systems are currently being widely applied for earthquake resistance. During the design stage for such systems, the displacement response and input energy of the isolation layer are two of the main concerns. The prediction of these values is also of vital importance during the early stages of the structural design. In this study, the simple prediction method of double concave friction pendulum (DCFP) bearings is proposed, which can relate the response displacement of the isolation layer to the ground velocity through energy transfer with sufficient accuracy. Two friction models (the precise and simplified model) and a constant friction coefficient of double concave friction pendulum (DCFP) bearings are comprehensively validated by full-scale sinusoidal dynamic tests under various conditions. In addition, a response analysis, based on previous studies, was conducted using the friction models under selected unidirectional earthquake excitations, and the accuracy of using the simplified model in the response analysis was verified. Based on the response analysis data, this article verifies and optimizes the proposed prediction method by parameterizing the characteristics of earthquakes and combining the energy balance in order to gain a deeper understanding of the design of the isolation systems.

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The effects of input earthquake characteristics on the nonlinear dynamic behavior of FPS isolated liquid storage tanks

Journal of Vibration and Control ◽

10.1177/1077546316655914 ◽

2016 ◽

Vol 24 (7) ◽

pp. 1264-1282 ◽

Cited By ~ 3

Author(s):

Saman Bagheri ◽

Mostafa Farajian

Keyword(s):

Passive Control ◽

Base Isolation ◽

Ground Motions ◽

Storage Tanks ◽

Ground Acceleration ◽

Pendulum System ◽

Aspect Ratios ◽

Liquid Storage ◽

Isolation Systems ◽

Friction Pendulum

There are several methods to reduce the seismic damages in liquid storage tanks. One of these methods is to use passive control devices, in particular seismic base isolators. Among the different base isolation systems, the Friction Pendulum System (FPS) whose period does not depend on the weight of the system is more appropriate for isolation of liquid storage tanks. The aim of this paper is to investigate the effects of peak ground acceleration (PGA) and pulselike characteristics of earthquakes on the seismic behavior of steel liquid storage tanks base isolated by FPS bearings. In addition, impact effects of the slider with the side retainer are investigated, as well as effects of tank aspect ratio, isolation period and friction coefficient. The obtained results of tanks with different aspect ratios indicate that the responses get more reduced due to isolation under far-field ground motions compared to near-fault ground motions. It is also seen that the response of a base isolated tank is affected when contact takes place with the side retainer of the FPS.

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Evaluating the Accuracy of an Equivalent Linear Model in Predicting Peak Displacement of Seismic Isolation Systems using Single Friction Pendulum Bearings

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.17687 ◽

2021 ◽

Author(s):

Thanh-Truc Nguyen ◽

Nhan Dinh Dao

Keyword(s):

Linear Model ◽

Seismic Isolation ◽

Peak Displacement ◽

Equivalent Linear ◽

Linear And Nonlinear ◽

Isolation Systems ◽

Seismic Isolation Systems ◽

Friction Pendulum ◽

Equivalent Linear Model ◽

Motion Types

This study evaluates the accuracy of an equivalent linear model in predicting peak nonlinear time-history displacement of seismic isolation systems with single friction pendulum bearings. To perform this evaluation, dynamic response of numerical models of 120 isolation systems subjected to 390 strong earthquake ground motions, including motions with pulse and motions without pulse, was analyzed and statistically processed. The results show that the equivalent linear model can partly predict the peak displacement of its counterpart nonlinear model. However, the equivalent model can also underestimate or overestimate the peak displacement. On average sense, the equivalent linear model underestimates small peak displacement and overestimates large peak displacement. It is also observed that the relationship between linear and nonlinear peak displacements depends on ground motion types. Based on the analysis data, equations representing relationship between linear and nonlinear peak displacements at different reliable levels for different ground motion types were proposed. These equations can be used in practice.

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Effects of Shape Memory Alloys on Response of Steel Structural Buildings within Near Field Earthquakes Zone

Civil Engineering Journal ◽

10.28991/cej-2020-03091550 ◽

2020 ◽

Vol 6 (7) ◽

pp. 1314-1327

Author(s):

Mahmoud Ahmadinejad ◽

Alireza Jafarisirizi ◽

Reza Rahgozar

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Base Isolation ◽

Near Field ◽

Seismic Zone ◽

Isolation System ◽

Residual Displacements ◽

Rubber Bearing ◽

Laminated Rubber Bearing ◽

Isolation Systems

Base isolation is one of the effective ways for controlling civil engineering structures in seismic zone which can reduce seismic demand. Also is an efficient passive control mechanism that protects its superstructure during an earthquake. However, residual displacement of base-isolation systems, resulting from strong ground motions, remain as the main obstacle in such system’s serviceability after the earthquake. Shape Memory Alloys (SMA) is amongst the newly introduced smart materials that can undergo large nonlinear deformations with considerable dissipation of energy without having any permanent displacement afterward. This property of SMA may be utilized for designing of base isolation system to increase the structure’s serviceability. Here, a proposed semi-active isolation system combines laminated rubber bearing system with shape memory alloy, to take advantage of SMAs high elastic strain range, in order to reduce residual displacements of the laminated rubber bearing. Merits of the system are demonstrated by comparing it to common laminated rubber bearing isolation systems. It is found that the optimal application of SMAs in base-isolation systems can significantly reduce bearings’ residual displacements. In this study, OpenSees program for a three dimensional six-storey steel frame building has been used by locating the isolators under the columns for investigating the feasibility of smart base isolation systems, i.e., the combination of traditional Laminated Rubber Bearing (LRB) with the SMA, in reducing the structure’s isolated-base response to near field earthquake records are examined. Also, a new configuration of SMAs in conjunction with LRB is considered which make the system easier to operate and maintain.

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Experimental Study of the XY-Friction Pendulum Bearing for Bridge Applications

Journal of Bridge Engineering ◽

10.1061/(asce)1084-0702(2009)14:3(193) ◽

2009 ◽

Vol 14 (3) ◽

pp. 193-202 ◽

Cited By ~ 7

Author(s):

Claudia C. Marin-Artieda ◽

Andrew S. Whittaker ◽

Michael C. Constantinou

Keyword(s):

Experimental Study ◽

Friction Pendulum

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Performance Analysis and Comparison of Two Base Isolation Systems with Super-Large Displacement Friction Pendulum Bearings

Applied Sciences ◽

10.3390/app10228235 ◽

2020 ◽

Vol 10 (22) ◽

pp. 8235

Author(s):

Peisong Wu ◽

Jinping Ou

Keyword(s):

Seismic Performance ◽

Base Isolation ◽

Design Method ◽

Horizontal Displacement ◽

Large Displacement ◽

Large Radius ◽

Isolation Layer ◽

Deformation Ability ◽

Isolation Systems ◽

Friction Pendulum

Isolation technology has been successfully applied in seismic migration. With increasing of seismic demand, seismic performance of isolation structures subjected to very-rare earthquakes need further improvement. However, the isolation layer generally lacks sufficient deformation ability under very-rare earthquakes due to the deformation limit of classical isolation bearing. In order to circumvent the difficulty, this paper develops two new isolation bearings, namely super-large displacement rotation friction pendulum bearing (SLDRFPB) and super-large displacement translation friction pendulum bearing (SLDTFPB). By setting spherical shells with large span and large radius, large horizontal displacement and small horizontal stiffness can be achieved. Safety of the isolation layer and the isolation effect of the superstructure can be greatly improved. SLDTFPB differs from SLDRFPB in the motion state of the superstructure and space utilization of the isolation layer, thus SLDRFPB and SLDTFPB are suitable for structures with different requirements. Due to rotation of the superstructure with SLDRFPB or sliding frames in SLDTFPB, the traditional design method of friction pendulum bearing is no longer suitable. We present a new procedure to accurately and conveniently evaluate seismic performance of two developed bearings. Numerical simulation shows that the seismic response of both the superstructure and isolation layer is small. Developed SLDRFPB and SLDTFPB have sufficient emergency capacity and isolation resilience when subjected to very-rare earthquakes.

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Experimental Study of a Full Scale Building Isolated With Multiple Friction Pendulum System With Multiple Sliding Interfaces

ASME 2011 Pressure Vessels and Piping Conference: Volume 8 ◽

10.1115/pvp2011-57352 ◽

2011 ◽

Author(s):

C. S. Tsai ◽

Y. M. Wang ◽

H. C. Su

Keyword(s):

Full Scale ◽

Shaking Table ◽

Shaking Table Tests ◽

Pendulum System ◽

Residual Displacements ◽

Fixed Base ◽

Sliding Interfaces ◽

Friction Pendulum ◽

Base Structure ◽

Friction Pendulum System

Presented in this paper is the performance evaluation of the multiple friction pendulum system (MFPS) with multiple sliding interfaces on seismic mitigation through a series of shaking table tests of a full scale MFPS-isolated building. In the tests, a three-story steel building of 40 tons in total weight, 3m and 4.5m in two horizontal directions and 9m in height, was equipped with MFPS isolators each with 4 sliding interfaces and subjected to various types of earthquakes to examine the efficiency of the isolators in reducing seismic response of a structure. Experimental results from shaking table tests tells that the roof accelerations, base shears, column shear forces have been significantly lessened with negligible residual displacements in the isolators while compared to the responses of a fixed-base structure.

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