Implementation and Validation of a Numerical Model for Lead-Rubber Seismic Isolation Bearings

2017 ◽  
Vol 35 (02) ◽  
pp. 153-165 ◽  
Author(s):  
T. Zhou ◽  
Y. F. Wu ◽  
A. Q. Li
Keyword(s):  
Numerical Model ◽  
Seismic Isolation ◽  
Model Simulation ◽  
Lateral Displacement ◽  
Piecewise Linear ◽  
Stability Limit ◽  
Lateral Interaction ◽  
Vertical Stiffness ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

ABSTRACTThis paper presents a numerical model for accurately representing the behaviors of lead-rubber bearings during earthquakes. This model, which is implemented in OpenSees as a user-defined element, accounts for the mechanical characteristics of bearings as follows: firstly, the bi-lateral interaction effect of hysteretic behaviors, as well as the variation in horizontal stiffness due to vertical load, is considered; secondly, the reduced vertical stiffness under large lateral displacement is incorporated by the piecewise linear formulation, and the linear reduction method is employed to determine the stability limit of bearings in the deformed configuration; furthermore, the cavitation and permanent damage effects in bearings are mathematically included. To validate the numerical model, simulation analyses are performed for a series of static and dynamic loading tests, and the numerical results show reasonable agreement with experimental ones, which indicates that the proposed model provides an effective tool for the failure mode analyses of bearings and the dynamic analyses of seismic isolated structures.

scholarly journals The Experimental Study on Mechanical Behavior of Conveyor Belt Rubber Bearings

2020 ◽  
Vol 10 (13) ◽  
pp. 4452
Author(s):  
Yifeng Wu ◽  
Yan Zhang ◽  
Aiqun Li ◽  
Guodong Zhang
Keyword(s):  
Shear Strain ◽  
Seismic Isolation ◽  
Low Cost ◽  
Damping Ratio ◽  
Influencing Factor ◽  
Core Layer ◽  
Conveyor Belt ◽  
Vertical Stiffness ◽  
Property Losses ◽  
Rubber Bearings

Fabric core conveyor belt rubber bearing (CBRB) with low cost and a simple manufacturing process has been proposed to further popularize seismic isolation technology in low-rise buildings, and four samples of such bearings have been produced, including four-layer, five-layer, five-layer with inner pattern and six-layer fabric core CBRBs. The vertical compression and the compression shear test are carried out to evaluate the performances of the four bearings. Results show that the vertical stiffness of the CBRB increases as the number of fabric core layer increases, while the damping ratio decreases, and the bearings can withstand a vertical pressure of 10 MPa. In addition, these bearings work very well within 100% shear strain, and the horizontal stiffness of the bearings decreases with increasing shear strain. In the meantime, as the number of fabric core layer increases, the effective horizontal stiffness of the bearings increases under 4 MPa compressive stress, and the damping ratio coefficient of the bearing is about 15%, when bearing sliding does not occur. The ultimate shear strain reached up to 200% for the four-layer bearing with obvious interlayer cracks, which means that the bonding quality between layers is the key influencing factor on the ultimate shear strain. In short, the proposed low-cost bearing has low horizontal stiffness and good energy dissipation capacity, so it is suitable for low-rise buildings in economically underdeveloped, high intensity areas, which can significantly improve their earthquake resistance and reduce casualties and property losses.

The Behavior of Bearings Used for Seismic Isolation under Rotation and Axial Load

1999 ◽  
Vol 15 (2) ◽  
pp. 225-244 ◽  
Author(s):  
Atsushi Mori ◽  
Peter J. Moss ◽  
Nigel Cooke ◽  
Athol J. Carr
Keyword(s):  
Seismic Isolation ◽  
Axial Loads ◽  
Isolation System ◽  
Elastomeric Bearings ◽  
Lead Rubber Bearings ◽  
Combined Action ◽  
Lift Off ◽  
Rubber Bearings ◽  
Bearing Behavior ◽  
Angle Of Rotation

The investigation described in this paper looked at both laminated elastomeric bearings and lead-rubber bearings in order to obtain a better understanding of the real bearing behavior under the combined action of rotation and axial loads when used in a seismic-isolation system. In particular, the investigation focused on the distributions of vertical pressure on the bearing faces and the degree of lift-off of the edges of the bearings as the angle of rotation increased.

Study on Seismic Isolation of High-Speed Railway Bridge Fabricated Lead Rubber Bearings

2011 ◽  
Vol 80-81 ◽  
pp. 409-413 ◽  
Author(s):  
Huan Tang ◽  
Hui Wang ◽  
Biao Zhou ◽  
Ling Kun Chen
Keyword(s):  
High Speed ◽  
Seismic Isolation ◽  
Computational Method ◽  
Bridge Engineering ◽  
Design Parameters ◽  
Vehicle Speed ◽  
Widespread Application ◽  
Bridge Model ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

Lead rubber bearings (LRB) is a new type of earthquake-resistance rubber bearings, formed by inserting lead-core into ordinary laminated rubber bearings, vertical supporting, horizontal displacement and hysteretic damping are hung in single unit together. Because lead-core can dissipate seismic energy and increase stiffness under load simultaneously, most of the requirements of the Seismic isolation system can be satisfied , the material-device has been found widespread application prospect in bridge Engineering. Equivalent linear model of hysteretic characteristics, computational method and the varying range of design parameters of LRB are presented. A full-bridge model of multi-span simple supported bridge with LRB is established in which box beam、LRB and piers are taken into account as a whole. By changing the property of earthquake excitation, ground motion intensity, vehicle speed and so on, the response of Bridge vibration system are analyzed, response law and characteristics of Bridge with LRB under different excitations are investigated systematically, compared with bridge with common bearings.

The Behavior of Bearings Used for Seismic Isolation under Shear and Axial Load

1999 ◽  
Vol 15 (2) ◽  
pp. 199-224 ◽  
Author(s):  
Atsushi Mori ◽  
Peter J. Moss ◽  
Nigel Cooke ◽  
Athol J. Carr
Keyword(s):  
Seismic Isolation ◽  
Axial Loads ◽  
Isolation System ◽  
Elastomeric Bearings ◽  
Lead Rubber Bearings ◽  
Combined Action ◽  
Lift Off ◽  
Rubber Bearings ◽  
Bearing Behavior ◽  
Angle Of Rotation

The investigation described in this paper looked at both laminated elastomeric bearings and lead-rubber bearings in order to obtain a better understanding of the real bearing behavior under the combined action of shear and axial loads when used in a seismic-isolation system. In particular, the investigation focused on the distributions of vertical pressure on the bearing faces and the degree of lift-off of the edges of the bearings as the shearing displacement and the angle of rotation increased.

scholarly journals An Experimental Study on the Mechanical Properties of a High Damping Rubber Bearing with Low Shape Factor

2021 ◽  
Vol 11 (21) ◽  
pp. 10059
Author(s):  
Zhenyuan Gu ◽  
Yahui Lei ◽  
Wangping Qian ◽  
Ziru Xiang ◽  
Fangzheng Hao ◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Dissipation ◽  
Shape Factor ◽  
Vertical Stiffness ◽  
Rubber Bearing ◽  
High Damping Rubber Bearing ◽  
Lead Rubber Bearings ◽  
Good Energy ◽  
High Damping Rubber ◽  
Rubber Bearings

A high damping rubber bearing (HDRB) is widely utilized in base-isolation structures due to its good energy dissipation capacity and environmentally friendly properties; however, it is incapable of isolating the vertical vibration caused by earthquakes and subways effectively. Thick rubber bearings with a low shape factor have become one of the important vertical isolation forms. This paper provides an experimental comparative study on high damping rubber bearings with low shape factor (HDRB-LSF), thick lead–rubber bearings (TLRB), and lead–rubber bearings (LRB). The abilities of the bearing and energy dissipation of the above bearings are analyzed contrastively considering the influence of vertical pressure, loading frequency, shear strain, and pre-pressure. Firstly, the HDRB-LSF, TLRB, and LRB are designed according to the Chinese Code for seismic design of buildings. Secondly, cyclic vertical compression tests and horizontal shear tests, as well as their correlation tests, are conducted, respectively. The vibrational characteristics and hysteresis feature of these three bearings are critically compared. Thirdly, a corrected calculation of vertical stiffness for the thick rubber bearings is proposed based on the experimental data to provide a more accurate and realistic tool measuring the vertical mechanical properties of rubber bearings. The test results proved that the HDRB-LSF has the most advanced performance of the three bearings. For the fatigue property, the hysteresis curves of the HDRB-LSF along with TLRB are plump both horizontally and vertically, thus providing a good energy dissipation effect. Regarding vertical stiffness, results from different loading cases show that the designed HDRB-LSF possesses a better vertical isolation effect and preferable environmental protection than LRB, a larger bearing capacity, and, similarly, a more environmentally friendly property than TLRB. Hence, it can avoid the unfavorable resonance effect caused by vertical periodic coupling within the structure. All the experimental data find that the proposed corrected equation can calculate the vertical stiffness of bearings with a higher accuracy. This paper presents the results of an analytical, parametric study that aimed to further explore the low shape factor concepts of rubber bearings applied in three-dimensional isolation for building structures.

scholarly journals The implementation of seismic isolation in the retrofit of a large wharf

2003 ◽  
Vol 36 (3) ◽  
pp. 208-217 ◽  
Author(s):  
Barry J. Davidson ◽  
Darrin K. Bell ◽  
Stuart F. George
Keyword(s):  
Seismic Isolation ◽  
Seismic Retrofit ◽  
Design Requirement ◽  
Lead Rubber Bearings ◽  
Lateral Restraint ◽  
Energy Absorbers ◽  
Rubber Bearings ◽  
Ductility Capacity ◽  
Post Tensioned

The paper describes the implementation of lead-rubber bearings as energy absorbers as part of the retrofit and upgrade of a large wharf. The key design requirement of the seismic retrofit was to ensure that the limited ductility capacity of the existing wharf piles was not exceeded. This was achieved by providing additional lateral restraint to the wharf in the form of groups of raking piles fastened to the wharf via post-tensioned lead-rubber bearings acting as energy absorbers.

Some Models of Elastomeric Seismic Isolation Devices

2013 ◽  
Vol 430 ◽  
pp. 356-361 ◽  
Author(s):  
Vasile Iancu ◽  
Gilbert Rainer Gillich ◽  
Claudiu Mirel Iavornic ◽  
Nicoleta Gillich
Keyword(s):  
Natural Rubber ◽  
Mathematical Models ◽  
Seismic Isolation ◽  
Horizontal Displacement ◽  
Numerical Results ◽  
Hysteretic Behaviour ◽  
Hybrid Device ◽  
Mathematical Relation ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

For the study and design of the elastomeric seismic devices is essential to know the mathematical relation between the horizontal displacement and the force leading it. In this paper we present mathematical models for three types of devices: (i) natural rubber bearings, (ii) lead rubber bearings and (iii) hybrid device combining the two first mentioned bearings. For all devices the specific domains of operation are determined and for each domain the relations connecting horizontal displacement and stiffness is contrived, highlighting the hysteretic behaviour in respect to ground excitation. Finally we present numerical results and a comparison between the three devices, defining the opportunity to involve them in specific applications, in function of the type and nature of the isolated structure.

Study on the damping efficiency of continuous beam bridge with constant cross-section applied by lead rubber bearings and fluid viscous dampers

2020 ◽  
Vol 51 (4-5) ◽  
pp. 85-92
Author(s):  
Li Zhen ◽  
Li Dejian ◽  
Peng Leihua ◽  
Lu Yao ◽  
Cheng Kepei ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Seismic Isolation ◽  
Seismic Energy ◽  
Continuous Beam ◽  
External Energy ◽  
Fluid Viscous Dampers ◽  
Continuous Beam Bridge ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Beam Bridge

Bridges are the lifelines of disasters in earthquake areas. Therefore, it is very necessary to ensure the safety and traffic function after earthquake. Seismic isolation refers to install external energy dissipation devices or external energy input devices in specific parts of engineering structures. There are certain differences in longitudinal and transverse seismic responses of multi-span continuous beam bridges by changing the seismic dynamic characteristics or dynamic effects of structures. It is difficult to achieve the purpose of seismic isolation in both horizontal directions using isolation devices alone. The rubber deformation ability of lead rubber bearings can effectively insulate, and the yield energy consumption ability of its lead core can effectively consume the seismic energy for damping. The horizontal resistance is very small under the creep load, and the stiffness decreases rapidly after yielding under the strong dynamic earthquake load; meanwhile, the seismic energy is dissipated by the hysteresis of bearing. Fluid viscous damper is a velocity-dependent energy dissipation device, which produces viscous damping force, provides strong restoring force for components, and has a good limit function. This process will also dissipate the seismic energy, so as to reduce the structural earthquake response. Using these two methods together, the horizontal seismic responses of multi-span continuous beam bridges can be effectively controlled at the same time. Based on this idea, this article takes a high-speed multi-span continuous beam bridge with equal section as the engineering background, and uses dynamic time history analysis method to discuss the seismic isolation effect of lead rubber bearings and fluid viscous dampers.

scholarly journals Seismic isolation of a printing press in Wellington, New Zealand

1992 ◽  
Vol 25 (3) ◽  
pp. 161-166 ◽  
Author(s):  
D. J. Dowrick ◽  
J. Babor ◽  
W. J. Cousins ◽  
R. I. Skinner
Keyword(s):  
Cast Iron ◽  
New Zealand ◽  
Seismic Hazard ◽  
Seismic Isolation ◽  
Printing Press ◽  
Isolation System ◽  
Building Housing ◽  
The Press ◽  
Lead Rubber Bearings ◽  
Rubber Bearings

This paper describes the seismic hazard near the Wellington Fault in Petone, and the measures taken to protect a new printing press made of brittle cast iron against earthquake attack. The printing press, owned by Wellington Newspapers, was located just 20 m from the Wellington Fault. Mounting the specially designed building housing the press on a seismic isolation system, lead-rubber bearings, reduced the estimated loads and deflections on the press by a factor of 8-10 compared with the non-isolated case. As a result the press should suffer only modest damage in earthquake shaking somewhat stronger than that required by the New Zealand earthquake code for the design of buildings.

Sign in / Sign up

Export Citation Format

Share Document