scholarly journals Experimental Investigation of a Base Isolation System Incorporating MR Dampers with the High-Order Single Step Control Algorithm

2017 ◽  
Vol 7 (4) ◽  
pp. 344 ◽  
Author(s):  
Weiqing Fu ◽  
Chunwei Zhang ◽  
Li Sun ◽  
Mohsen Askari ◽  
Bijan Samali ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Control Algorithm ◽  
Base Isolation ◽  
Single Step ◽  
High Order ◽  
Isolation System ◽  
Mr Dampers ◽  
Base Isolation System ◽  
Step Control

Modified H2/LQG control algorithm for designing a multi-objective semi-active base isolation system

2018 ◽  
Vol 24 (23) ◽  
pp. 5693-5704
Author(s):  
Mohtasham Mohebbi ◽  
Hamed Dadkhah ◽  
Hamed Rasouli Dabbagh
Keyword(s):  
Control Algorithm ◽  
Base Isolation ◽  
Control Algorithms ◽  
Time Step ◽  
Isolation System ◽  
Multi Objective ◽  
Lqg Control ◽  
Base Isolation System ◽  
Isolation Systems ◽  
Active Base

This paper proposes a modified version of H2/Linear Quadratic Gaussian (H2/LQG) control algorithm (MH2/LQG) to design effective semi-active base isolation systems with a supplemental magneto-rheological (MR) damper for simultaneously controlling the base drift and acceleration of a structure. In the proposed MH2/LQG control algorithm, the weighting parameter defined in the semi-active control law is considered variable during the seismic loading and is adjusted at each time step to prevent the device from applying excessive damping force to the structure. As a result, the supplemental control system is designed not only to reduce the base drift of the isolated structure but also to restrict increases that may occur in accelerations imparted to the superstructure due to excessive damping forces. As a numerical example to illustrate the proposed method, an isolated four-story structure is subjected to different earthquake records and the semi-active base isolation system is designed using both H2/LQG and MH2/LQG control algorithms. The results show the effectiveness of the proposed MH2/LQG control algorithm in designing semi-active base isolation systems which can provide a proper simultaneous control of the base drift and floor accelerations. In addition, comparing the performance of the MH2/LQG and multi-objective H2/LQG control algorithms shows that while the two design procedures work similarly in mitigating the maximum base drift, the MH2/LQG control algorithm is more effective in reducing the maximum floor acceleration.

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.

Hysteresis Loops of Base Isolation System - An Overview

2021 ◽  
Vol 879 ◽  
pp. 189-201
Author(s):  
M.A. Amir ◽  
N.H. Hamid
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Base Isolation ◽  
Numerical Models ◽  
Hysteresis Loops ◽  
Human Beings ◽  
Rc Buildings ◽  
Isolation System ◽  
Base Isolation System ◽  
Isolation Systems

Recently, there are a lot of technological developments in the earthquake engineering field to reduce structural damage and one of them is a base isolation system. The base isolation system is one of the best technologies for the safety of human beings and properties under earthquake excitations. The aim of this paper is to review previous research works on simulation of base isolation systems for RC buildings and their efficiency in the safety of these buildings. Base isolation decouples superstructure from substructure to avoid transmission of seismic energy to the superstructure of RC buildings. The most effective way to assess the base isolation system for RC building under different earthquake excitations is by conducting experiment work that consumes more time and money. Many researchers had studied the behavior of base isolation system for structure through modeling the behavior of the base isolation in which base isolator is modeled through numerical models and validated through experimental works. Previous researches on the modeling of base isolation systems of structures had shown similar outcomes as the experimental work. These studies indicate that base isolation is an effective technology in immunization of structures against earthquakes.

Dynamic Nonlinear Analysis of an Hybrid Base Isolation System with Viscous Dampers and Friction Sliders in Parallel

2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Nonlinear Analysis ◽  
Base Isolation ◽  
Three Dimensional ◽  
Time History ◽  
Seismic Action ◽  
Viscous Dampers ◽  
Isolation System ◽  
Fixed Base ◽  
Base Isolation System ◽  
Dynamic Nonlinear Analysis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.

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