scholarly journals Performance of Seismic Restrainer with SMA Springs for Sliding Isolation of Single-Layer Spherical Lattice Shells

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Peng Zhuang ◽  
Wenting Wang
Keyword(s):  
Seismic Response ◽  
Large Scale ◽  
Time History ◽  
Single Layer ◽  
Helical Spring ◽  
Hysteresis Model ◽  
Isolation System ◽  
Peak Displacement ◽  
Sma Spring ◽  
Lattice Shell

The seismic response of a single-layer spherical lattice shell controlled by restorable sliding isolator is studied under different seismic excitations. The isolation system consists of flat steel-Teflon sliding isolators and superelastic SMA spring restrainers. The NiTi-SMA is used to fabricate helical spring for recentering control of the isolation system. In the first step of this investigation, the configuration scheme and functioning mechanism of a novel SMA spring restrainer are introduced briefly. Then, realistic mechanical behavior of large-scale superelastic NiTi helical spring is studied through a set of cyclic experimental tests. According to the obtained hysteresis loops, a mechanical model combining multilinear model and hysteresis model is developed to simulate the overall response of the SMA-based seismic restrainer. Besides, the sliding isolator is evaluated using a bilinear force-displacement hysteresis model. Finally, a 60 m span single-layer spherical lattice shell with substructure is modeled with finite element program. Nonlinear time history analyses of the controlled and uncontrolled lattice shell are performed considering multidimensional seismic inputs. The study shows that the seismic response of the controlled lattice shell can be effectively reduced by using isolation and control devices. Furthermore, the seismic response of the isolation system such as peak displacement and residual displacement can be effectively controlled by using the developed SMA spring restrainers.

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.

scholarly journals Seismic Vibration Control of Building with Lead Rubber Bearing Isolator

10.29007/pvzx ◽  
2018 ◽  
Author(s):  
Kishan Bhojani ◽  
Vishal Patel ◽  
Snehal Mevada
Keyword(s):  
Seismic Response ◽  
Base Isolation ◽  
Time History ◽  
Dynamic Parameter ◽  
Base Shear ◽  
Maximum Displacement ◽  
Maximum Acceleration ◽  
Isolation System ◽  
Loma Prieta Earthquake ◽  
Base Isolation System

During the life span of structure there may be an effect of vibration. Due to vibration there may be major or minor damage in building. Base isolation is best method to reduce the seismic response of the structure. This paper gives idea about base isolation system which can be used in multi-story building to reduce seismic response of the structure. This paper represents the initialize study of dynamic parameter like effective damping for four earthquake time history. In this paper the optimum effective damping has been found out under the effect of Loma Prieta earthquake time history. The parametric study has been conducted to evaluate the effect on maximum displacement, maximum acceleration, maximum base shear in bare frame and frame with isolator.

A Novel Orthogonally Separated Isolation System and Its Seismic Performance on a Curved Concrete Bridge

2021 ◽  
pp. 2150158
Author(s):  
Ben Sha ◽  
Chenxi Xing ◽  
Junhong Xu ◽  
Hao Wang ◽  
Aiqun Li
Keyword(s):  
Seismic Response ◽  
Shear Force ◽  
Ground Motions ◽  
Time History ◽  
Relative Displacement ◽  
Analytical Models ◽  
Orthogonal Direction ◽  
Isolation System ◽  
Curved Bridge ◽  
Planar Rotation

The seismic response of curved concrete bridges is complex because of the geometric irregularity and induced planar rotation of the deck, which can magnify the displacement of the deck and deformation of the bearings. To control the planar rotation and thus the seismic response of the curved bridge, an orthogonally separated isolation system (OSIS) is proposed, which consists of the upper and lower isolation parts. With this, the planar relative displacement of the common isolation system is decomposed into the relative displacement of the upper part in one direction and the relative displacement of the lower isolation part in the orthogonal direction. Therefore, the planar rotation can be restrained and the seismic demand of the isolation bearing is decoupled. The analytical models of a curved bridge and the OSIS are established in OpenSees. A suite of 118 ground motions, of which 80 are ordinary and 38 are pulse-like, is selected as input with 24 different angles of incidence so as to consider the seismic variation. Nonlinear dynamic time-history analyses of the two models are conducted to evaluate the effectiveness of the OSIS. The results show that the OSIS can effectively decrease the deck displacement, the bearing deformation and the pier column shear force, especially under the ground motions with higher intensities, while the shear force increases slightly on the abutment.

Assessment of seismic performance of an isolated structure equipped with a friction damper with coupling mechanism and an oil damper

2020 ◽  
pp. 136943322098165
Author(s):  
Shuang Zou ◽  
Heisha Wenliuhan ◽  
Norio Inoue
Keyword(s):  
Seismic Response ◽  
Time History ◽  
Coupling Mechanism ◽  
Control Force ◽  
Friction Damper ◽  
Analysis Model ◽  
Control Effect ◽  
Maximum Displacement ◽  
Isolation System ◽  
Isolation Layer

In this study, a friction damper with a coupling mechanism (FDC) and an oil damper were added to the isolation layer of an isolated structure. Using the Kelvin collision analysis model, a time history analysis was performed by considering a possible impact in the isolation layer. Based on a comparative analysis of the seismic control effect, the following conclusions can be drawn. The combined isolation system proposed in this study gradually increases the attenuation performance of the isolation layer according to the magnitude of the earthquake by taking complete advantage of the FDC and oil damper and satisfies different performance requirements of the isolation layer of different magnitudes of earthquakes. In addition to the same control effect as the combined isolation system for seismic fortification intensity earthquakes, the best control effect can be achieved using a small control force for frequent earthquakes. Overall, the control effect on the acceleration of structural seismic response is pronounced. In the case of a rare earthquake, for not amplifying the seismic response acceleration of isolated structure, the maximum displacement of the isolation layer is controlled within the reserved safety range to avoid collision and damage between the isolation layer and surrounding maintenance structure.

Performance of Bridges Isolated with Sliding-Lead Rubber Bearings Subjected to Near-Fault Earthquakes

2020 ◽  
Vol 20 (02) ◽  
pp. 2050023 ◽  
Author(s):  
Wenzhi Zheng ◽  
Hao Wang ◽  
Hong Hao ◽  
Kaiming Bi ◽  
Huijun Shen
Keyword(s):  
Time History ◽  
Isolation System ◽  
Peak Displacement ◽  
Residual Displacement ◽  
Near Fault ◽  
Lead Rubber Bearing ◽  
Base Forces ◽  
Near Fault Earthquakes ◽  
Rubber Bearings ◽  
Nonlinear Time History

This paper investigates the seismic performance of bridges installed with a sliding-lead rubber bearing (LRB) isolation system subjected to near-fault earthquakes. A three-span continuous bridge isolated with sliding-LRB system is used as an example. Nonlinear time history analyses are conducted to investigate the sensitivity effects of isolation period, friction coefficient and sliding displacement limit on the bridge responses. The responses of the sliding-LRB system are compared with those of the conventional LRB system. The results show that the base forces of the piers can be reduced by employing proper friction coefficients. However, the residual displacement of the sliding-LRB system may be larger compared with that of the conventional LRB system. To overcome this disadvantage, an improved solution to reduce the residual displacement is proposed with its effectiveness investigated. It was also demonstrated that the residual displacement and peak displacement can be effectively reduced by employing the shape memory alloy devices in the sliding-LRB system without significantly increasing the base forces.

Seismic Response Analysis of Free Long-Span Submarine Flexible Pipelines under Earthquakes

2014 ◽  
Vol 580-583 ◽  
pp. 1704-1707
Author(s):  
Yu Lin Deng ◽  
Yu Bian ◽  
Fan Lei
Keyword(s):  
Seismic Response ◽  
Fluid Structure Interaction ◽  
Time History ◽  
Response Analysis ◽  
Seismic Safety ◽  
Peak Displacement ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Finite Element Software ◽  
Long Span

Submarine pipelines are described as the lifeblood of offshore oil and it is crucial to ensure the seismic safety of the submarine pipelines. Based on the fluid-structure interaction numerical analysis method and by using finite element software ADINA, the analysis models of the free long-span submarine flexible pipelines under earthquakes were established. By employing dynamic time-history method, the influences of fluid-structure interaction on the seismic response of the submarine pipelines were researched. The results showed that the peak normal stress and the peak displacement of submarine pipelines’ mid-span considering the influences of the fluid-structure interaction are greater than those without considering the influences, and the influences of the fluid-structure interaction on the seismic response of the submarine pipelines will increase with the increase of the submarine pipelines‘ diameter.

Finite Element Analysis of a Single-Layer Reticulated Dome and the Suspendome under Impact Loading

2012 ◽  
Vol 594-597 ◽  
pp. 844-848
Author(s):  
Liang Zheng
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Impact Force ◽  
Numerical Models ◽  
Time History ◽  
Single Layer ◽  
Impact Response ◽  
Element Analysis ◽  
Peak Displacement ◽  
The Impact

This paper treats the impact force and the displacement of the lamella single-layer reticulated dome and the suspendome under axial impact loading using non-linear finite element techniques. The influence of loading parameters and the cable force of the suspendome on the impact response is investigated using validated numerical models. Results are quantified in terms of important impact response parameters and indicate that the peak displacement of the lamella single-layer reticulated dome and the suspendome can be clearly divided into four stages with time , and time history curve of the impact force can be divided into three stages.

Seismic Response Analysis of Container Crane

2012 ◽  
Vol 503-504 ◽  
pp. 1104-1107
Author(s):  
Shi Qing Lu ◽  
Han Bin Xiao ◽  
Ping Deng
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Large Scale ◽  
Time History ◽  
Element Model ◽  
Response Analysis ◽  
Container Cranes ◽  
Container Crane ◽  
Critical Nodes ◽  
History Analysis

Earthquakes pose a threat to large-scale container cranes. Previous earthquakes damaged many container cranes, which had a significant impact on business interruption losses of the port. In this paper, a container crane’s seismic response is analyzed in ANSYS. First, a finite element model of a container crane is developed. Then, based on the equations of structural dynamics, the four most important modes of the container crane are extracted. Finally, a time history analysis is conducted to obtain the displacements of some critical nodes on the crane model under the excitation of an earthquake wave. The result of this paper provides a reference for the seismic design of container cranes.

The Seismic Response Analysis of Isolation Structure with Shape Memory Alloy Re-Centring Dampers

2011 ◽  
Vol 99-100 ◽  
pp. 81-90
Author(s):  
Xiao Yu Miao ◽  
She Liang Wang ◽  
Yu Jiang Fan
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Response ◽  
Time History ◽  
Response Analysis ◽  
Property A ◽  
Isolation System ◽  
Rubber Bearing ◽  
History Analysis ◽  
Laminated Rubber Bearing

Shape memory alloy (SMA) is provided with preferable damp capacity at pseudo-elasticity state, applying this property, a SMA re-centring damper is introduced by some scholars. In this paper, the new isolation system combining the above damper with laminated rubber bearing is proposed, so as to obtain preferable isolation character and re-centring capacity. To illustrate the feasibility and effectiveness of the proposed system, the following work is done: First, according the constitution model of SMA at pseudo-elasticity state the program is compiled, then the mechanical behavior of damper is simulated and the hysteretic curve is obtained. Based on the above, a linear restoring model for SMA re-centring damper is put forward. And then, the program based on the theory of story model for shear tape is compiled to conduct elasto-plastic time history analysis of practical structure examples, According to the results, the seismic response of structure is significantly reduced, and the fully re-centring capacity after earthquake is obtained by this isolation system.

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