scholarly journals Reducing the lateral displacement of lead rubber bearing isolators under the near field earthquakes by crosswise dissipaters connected to rigid support structure

2021 ◽  
Vol 30 (4) ◽  
Author(s):  
Kourosh Talebi Jouneghani
Keyword(s):  
Base Isolation ◽  
Lateral Displacement ◽  
Near Field ◽  
Frame Structure ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Isolation System ◽  
Lead Rubber Bearing ◽  
Base Isolation System ◽  
The Stability

The purpose of base isolation is to absorb earthquake energy, prolong the life of the structure, and enable the structure to be similar to a rigid body. However, since resonance can occur due to the closeness of the period of structures to the long period and large velocity pulses of the near field earthquakes, the stability of these buildings greatly reduces, and with the large displacement above isolation level, sometimes, tendency of overturning is created in isolators leading to their destruction. The main objective of this study is to significantly reduce the lateral displacement of base isolation subjected to near field earthquakes. In this research, seismic response calculation has been carried out for five steel moment frame structure with the 3, 5, 8, 11, and 14 stories in two states of with and without stiff core structure and energy dissipaters. The analyses has been done under fourteen scaled records of seven near-source and seven far-source earthquakes. It has been shown that the lateral displacement of base isolation system can be reduced by 87% for low-rise buildings, and 77% for high-rise buildings.

A study on seismic isolation of building used LRB

2020 ◽  
Vol 6 (2) ◽  
pp. 52
Author(s):  
Muhammet Yurdakul ◽  
Mehmet Burak Yıldız
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Dynamic Loads ◽  
Isolation System ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Earthquake Design ◽  
Base Isolation System ◽  
Internal Forces ◽  
Storey Building

Base isolation system with lead rubber bearing (LRB) is commonly used to prevent structure against to damage of earthquake. Design of LRB system is detailed in this study. The isolated building with LRB design according to Uniform Building Code (UBC-97) and fixed building were examined. The six-storey building with LRB and fixed building were modelled in SAP2000 with the same dynamic loads. The relative floor displacement and internal forces of the seismic isolated and fixed building are compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and transverse reinforcement of isolated building is smaller than fixed building about 36%, 40% respectively.

A Novel Seismic Base Isolation System Consisting of a Lead Rubber Bearing in Series with a Friction Slider. Part I: Nonlinear Modeling of the System

2012 ◽  
Vol 256-259 ◽  
pp. 2185-2192
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis ◽  
Mario Pasquino
Keyword(s):  
Base Isolation ◽  
Nonlinear Modeling ◽  
Isolation System ◽  
Nonlinear Finite Elements ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Base Isolator ◽  
Base Isolation System ◽  
In Series ◽  
Seismic Base Isolation

In this paper a new seismic base isolator, called High Damping Hybrid Seismic Isolator (HDHSI), is proposed. It is obtained by the assembly in series of a Lead Rubber Bearing (LRB) and a Friction Slider (FS) with a high friction coefficient. The HDHSI device is in contrast with the Resilient-Friction Base Isolator (R-FBI) with the aim of optimizing the Electricité De France (EDF) system. The mathematical model of a structure base isolated by a HDHSI system is analyzed with a two Degree of Freedom System (2-DOF) in which the superstructure is assimilated to a rigid body. Nonlinear finite elements are adopted for modeling the HDHSI device. A dynamic nonlinear analysis is performed and the hysteretic cycles are derived and evaluated for the single components and for the innovative HDHSI device.

Smart Base Isolation Control Adopted Semi-Active Fuzzy Strategy for Seismic Response of Structure

2011 ◽  
Vol 255-260 ◽  
pp. 2515-2519 ◽  
Author(s):  
Gui Yun Yan ◽  
Wen Jun Wu
Keyword(s):  
Seismic Response ◽  
Base Isolation ◽  
Simulation Analysis ◽  
Magnetorheological Damper ◽  
Frame Structure ◽  
Structural Vibration ◽  
Isolation System ◽  
Base Isolation System ◽  
Fuzzy Control Strategy ◽  
Smart Base Isolation

According to the disadvantages of the effects that base isolation was limited to high frequency components of seismic wave, smart base isolation system consisting of rolling isolation bearing and magnetorheological damper was applied to structural vibration control. Based on magnetorheological damper employing a Sigmoid model, a semi-acive fuzzy control strategy suitable for smart base isolation was presented. Simulation analysis was carried out to a two-story steel frame structure employing smart base isolation in the action of different kinds and magnitudes of earthquake wave. The results show that smart base isolation system is reliable and effective, and seismic response can be controlled effectively by semi-active fuzzy strategy.

scholarly journals Performance of 2-D Frame Equipped With Base isolation System under Dynamic Loadings

2020 ◽  
Vol 184 ◽  
pp. 01099
Author(s):  
N. Omprakash Reddy ◽  
A. Manchalwar
Keyword(s):  
Design Research ◽  
Passive Control ◽  
Base Isolation ◽  
Isolation System ◽  
Control Techniques ◽  
Rc Frames ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Base Isolation System ◽  
Structural Responses

Building responses have become a major concern in design research. Passive control techniques are implemented to improve structure efficiency. The present research aims to assess the efficiency of base isolation system for a 2D frame and to enhance the performance of structures that are subjected to seismic ground excitations and ground vibrations induced by blast. Two moments of resistant RC frames were studied and output of the isolator (Lead / Rubber Bearing) was observed to reduce structural responses. In SAP2000 non-linear dynamic analysis is conducted to compare normal and irregular moment-resistant frames and structural responses with and without passive control techniques. Isolators are constructed based on time of isolation. Reduction of structural responses is assessed by passive control techniques, and comparative analysis is performed. Mitigating systemic retaliation is affected by the implementation of passive control system.

scholarly journals Performance Evaluation of the Base Isolation Technique on the Blast Mitigation of Spatial Structures

2020 ◽  
Vol 30 (3) ◽  
pp. 134-160
Author(s):  
Kuppalli Krishne Gowda Kiran ◽  
Ehsan Noroozinejad Farsangi
Keyword(s):  
Base Isolation ◽  
Spatial Structures ◽  
Isolation System ◽  
Isolation Technique ◽  
Seismic Control ◽  
Long Span ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Base Isolation System ◽  
Airport Terminals

Abstract Unpredictable threat and danger may occur in a structural system due to blast loading. Long-span spatial structures are very practical and common in airport terminals, exhibition centers, stadiums, and other public buildings. For high-rise and multi-story structures, horizontal pressure plays a major role in the level of damage to a structure, whereas long-span structures may be influenced by both horizontal and vertical pressure. In the current study, the applicability of lead rubber bearing (LRB) has been evaluated on a low-rise, long-span structure. The analysis is carried out by using the MATLAB Simulink platform. The simulation results indicate that the base isolation system which is usually adopted for seismic control of structures can adequately reduce the structural responses under blast loadings.

scholarly journals Influence of Elastomeric Bearings in Tension on the Seismic Performance of Base-Isolated r.c. Buildings

2020 ◽  
Vol 11 (1) ◽  
pp. 82
Author(s):  
Fabio Mazza ◽  
Mirko Mazza
Keyword(s):  
Base Isolation ◽  
Nonlinear Models ◽  
Vertical Component ◽  
Computer Code ◽  
Nonlinear Phenomena ◽  
Isolation System ◽  
Elastomeric Bearings ◽  
Near Fault ◽  
Base Isolation System ◽  
Near Fault Earthquakes

Elastomeric bearings are commonly used in base-isolation systems to protect the structures from earthquake damages. Their design is usually developed by using nonlinear models where only the effects of shear and compressive loads are considered, but uncertainties still remain about consequences of the tensile loads produced by severe earthquakes like the near-fault ones. The present work aims to highlight the relapses of tension on the response of bearings and superstructure. To this end, three-, seven- and ten-storey r.c. framed buildings are designed in line with the current Italian seismic code, with a base-isolation system constituted of High-Damping-Rubber Bearings (HDRBs) designed for three values of the ratio between the vertical and horizontal stiffnesses. Experimental and analytical results available in literature are used to propose a unified nonlinear model of the HDRBs, including cavitation and post-cavitation of the elastomer. Nonlinear incremental dynamic analyses of the test structures are carried out using a homemade computer code, where other models of HDRBs considering only some nonlinear phenomena are implemented. Near-fault earthquakes with comparable horizontal and vertical components, prevailing horizontal component and prevailing vertical component are considered as seismic input. Numerical results highlight that a precautionary estimation of response parameters of the HDRBs is attained referring to the proposed model, while its effects on the nonlinear response of the superstructure are less conservative.

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