A BI-AXIAL EXTENDED BI-LINEAR HYSTERETIC MODEL FOR LAMINATED RUBBER BEARINGS

2018 ◽  
Vol 74 (3) ◽  
pp. 458-472
Author(s):  
Junji YOSHIDA ◽  
Kazushi KOIZUMI
Keyword(s):  
Hysteretic Model ◽  
Rubber Bearings

Influence of the Strain Hardening of HDRBs in the Evaluation of the Seismic Response of a RC Base Isolated Structure

2012 ◽  
Vol 602-604 ◽  
pp. 1546-1554
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis ◽  
Mario Pasquino
Keyword(s):  
Strain Hardening ◽  
Seismic Response ◽  
Base Isolation ◽  
Cyclic Behavior ◽  
Hysteretic Model ◽  
Isolation System ◽  
Limit Value ◽  
Hardening Effect ◽  
Base Isolation System ◽  
Rubber Bearings

In this paper we have analyzed the influence of the strain hardening behavior of High Damping Rubber Bearings (HDRBs) adopted for a base isolation system of a Reinforced Concrete (RC) isolated structure. For the modeling of the rubber isolators we have adopted an evolution of the Bouc-Wen’s hysteretic model taking into account the incremental hardening effect which appears when the shear strain of the HDRB exceeds the limit value around 100% usually adopted in design practice. The incremental hardening effect is sometimes neglected in the design but it is an important aspect because it ensures a seismic protection of the base isolated structure also in presence of exceptional seismic events for intensity or frequency content. In this paper we have highlighted the significant influence of this phenomenon in the seismic response of the isolated structure by reporting the cyclic behavior of a HDRB respectively neglecting and considering this aspect.

scholarly journals Numerical Solutions for Nonlinear High Damping Rubber Bearing Isolators: Newmark’s Method with Netwon-Raphson Iteration Revisited

2018 ◽  
Vol 48 (1) ◽  
pp. 46-58
Author(s):  
A.A. Markou ◽  
G.D. Manolis
Keyword(s):  
Numerical Solutions ◽  
Field Tests ◽  
Hysteretic Model ◽  
Low Friction ◽  
Sliding Bearings ◽  
Vibration Field ◽  
High Damping Rubber Bearings ◽  
High Damping Rubber ◽  
Rubber Bearings ◽  
Raphson Iteration

AbstractNumerical methods for the solution of dynamical problems in engineering go back to 1950. The most famous and widely-used time stepping algorithm was developed by Newmark in 1959. In the present study, for the first time, the Newmark algorithm is developed for the case of the trilinear hysteretic model, a model that was used to describe the shear behaviour of high damping rubber bearings. This model is calibrated against free-vibration field tests implemented on a hybrid base isolated building, namely the Solarino project in Italy, as well as against laboratory experiments. A single-degree-of-freedom system is used to describe the behaviour of a low-rise building isolated with a hybrid system comprising high damping rubber bearings and low friction sliding bearings. The behaviour of the high damping rubber bearings is simulated by the trilinear hysteretic model, while the description of the behaviour of the low friction sliding bearings is modeled by a linear Coulomb friction model. In order to prove the effectiveness of the numerical method we compare the analytically solved trilinear hysteretic model calibrated from free-vibration field tests (Solarino project) against the same model solved with the Newmark method with Netwon-Raphson iteration. Almost perfect agreement is observed between the semi-analytical solution and the fully numerical solution with Newmark’s time integration algorithm. This will allow for extension of the trilinear mechanical models to bidirectional horizontal motion, to time-varying vertical loads, to multi-degree-of-freedom-systems, as well to generalized models connected in parallel, where only numerical solutions are possible.

scholarly journals Responses of Building Base Isolated With High Damping Rubber Bearings

2019 ◽  
Vol 8 (9) ◽  
pp. 1287-1292
Keyword(s):  
Seismic Isolation ◽  
Design Procedure ◽  
Hysteretic Model ◽  
Base Shear ◽  
Ground Acceleration ◽  
Element Analysis ◽  
High Damping Rubber Bearings ◽  
Fixed Base ◽  
High Damping Rubber ◽  
Rubber Bearings

Seismic isolation is one of the most efficient techniques to protect structures against earthquakes. Rubber bearings are suitable for low-rise and medium-rise buildings due to its durability and easy fabrication. This paper presents the hori-zontal response of a six-storey base-isolated building using high damping rubber bearings (HDRB) under two ground motions of earthquakes as types I and II in JRA (2002) by finite element analysis. In this analysis, these bearings are mod-elled by the bilinear hysteretic model which is indicated in JRA and AASHTO. Comparison of horizontal response including base shear force and roof level acceleration between the two cases: base-isolated building and fixed-base building is carried out to evaluate the effectiveness of the use of HDRB on the protection of buildings from earthquakes. The numerical results show that the peak value of roof floor acceleration of the fixed-base building is two times higher than that of the base-isolated building, and the floor accelerations depend on the peak values of ground acceleration. In addition, the step-by-step design procedure for deter-mining the size of HDRBs used for buildings is also presented in this paper.

Dynamic Response on Earthquake Analysis of Bridge Structure Isolated by Lead-Core Rubber Bearing

2010 ◽  
Vol 163-167 ◽  
pp. 4251-4256
Author(s):  
Hai Xu Yang ◽  
Hai Biao Wang ◽  
Bao Kuan Li ◽  
Jian Gang Yao
Keyword(s):  
Dynamic Response ◽  
Dynamic Performance ◽  
Economic Benefits ◽  
Earthquake Resistance ◽  
Bridge Structure ◽  
Hysteretic Model ◽  
Analysis Model ◽  
Construction Design ◽  
Rubber Bearing ◽  
Rubber Bearings

The dynamic analysis of earthquake responses of one simple bridge structure supported by hinged and rolled bearing and another simple bridge structure isolated by lead-core rubber bearings was described in elastic-plastic range. The relative displacements and accelerations of the structures were calculated under different amplitude earthquake waves in order to observe the influence of lead-core rubber bearing on earthquake- resistance of bridges. The availability of the analysis model, hysteretic model and relevant parameters adopted as well as the computation program developed are verified. According to the analysis of dynamic response data, the lead-core rubber bearings with proper parameters are used to improve the dynamic performance of the structures, the seismic response of the bridge deck and pier would therefore be greatly reduced, the safety and seismic performance of the structure are globally raised, earthquake- resistance could be increased, and rather good economic benefits have been achieved as well. The analysis can provide accurately the reference basis for construction design.

SEISMIC CAPACITY OF MEDIUM SIZE CONTINUOUS BRIDGES WITH LEAD-RUBBER BEARINGS

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 199-206
Author(s):  
Bertha Olmos ◽  
José Jara ◽  
José Luis Fabián
Keyword(s):  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Elastic Behaviour ◽  
Medium Size ◽  
Nonlinear Behaviour ◽  
Seismic Capacity ◽  
Damage Scenarios ◽  
Isolation Systems ◽  
Rubber Bearings

This paper investigates the effects of the nonlinear behaviour of isolation pads on the seismic capacity of bridges to identify the parameters of base isolation systems that can be used to improve seismic performance of bridges. A parametric study was conducted by designing a set of bridges for three different soil types and varying the number of spans, span lengths, and pier heights. The seismic responses (acceleration, displacement and pier seismic forces) were evaluated for two structural models. The first model corresponded to the bridges supported on elastomeric bearings with linear elastic behaviour and the second model simulated a base isolated bridge that accounts for the nonlinear behaviour of the system. The seismic demand was represented with a group of twelve real accelerograms recorded on the subduction zone on the Pacific Coast of Mexico. The nonlinear responses under different damage scenarios for the bridges included in the presented study were estimated. These results allow determining the seismic capacity of the bridges with and without base isolation. Results show clearly the importance of considering the nonlinear behaviour on the seismic performance of bridges and the influence of base isolation on the seismic vulnerability of medium size bridges.

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