DESIGN FORCE TRANSMITTED BY ISOLATION SYSTEM COMPOSED OF LEAD-RUBBER BEARINGS AND VISCOUS DAMPERS

2010 ◽  
Vol 10 (02) ◽  
pp. 287-298 ◽  
Author(s):  
J. S. HWANG ◽  
C. F. HUNG ◽  
Y. N. HUANG ◽  
S. J. WANG
Keyword(s):  
Phase Angle ◽  
Seismic Isolation ◽  
Soft Soil ◽  
Near Field ◽  
Viscous Dampers ◽  
Maximum Displacement ◽  
Isolation System ◽  
Lead Rubber Bearings ◽  
Response History Analysis ◽  
Rubber Bearings

In seismic isolation design of structures located at soft soil sites or near field areas, viscous dampers (VD) are often included as part of the isolation system to minimize its maximum displacement. Due to the 90° phase angle existing between the force and displacement of the VD, the maximum force transmitted by the isolation system cannot be calculated by simply combining the forces of the isolation bearings, such as lead-rubber bearings (LRB) or high damping rubber bearings (HDRB), and VD in association with the design displacement. Conforming to the code-specified equivalent lateral response procedure for isolation design, this paper presents a formula for determining the seismic design force of the combined LRB and VD isolation system, taking into account the phase angle between the combined force of the LRB and VD and the displacement of the isolation system. The numerical results have shown that the maximum responses of the isolation system predicted by the proposed formula are conservative and comparable with those from the inelastic dynamic response history analysis.

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.

scholarly journals MULTIPLE REGRESSION MODELING OF NATURAL RUBBER SEISMIC-ISOLATION SYSTEMS WITH SUPPLEMENTAL VISCOUS DAMPING FOR NEAR-FIELD GROUND MOTION

2013 ◽  
Vol 19 (5) ◽  
pp. 665-682 ◽  
Author(s):  
Mohammad H. Alhamaydeh ◽  
Samer A. Barakat ◽  
Farid H. Abed
Keyword(s):  
Natural Rubber ◽  
Multiple Regression ◽  
Ground Motion ◽  
Seismic Isolation ◽  
Near Field ◽  
Earthquake Ground Motion ◽  
Maximum Displacement ◽  
Fixed Base ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

This work presents the development and implementation of the Multiple Regression Analysis (MRA) model to Seismic-Isolation (SI) systems consisting of Natural Rubber Bearings and Viscous Fluid Dampers subject to Near-Field (NF) earthquake ground motion. A model representing a realistic five-story base-isolated building is used. Several damper properties are used in creating an array of feasible combinations for the SI system. Two ensembles of seven NF earthquake records are utilized representing two seismic hazard levels. The key response parameters investigated are the Total Maximum Displacement, the Peak Damper Force and the Top Story Acceleration Ratio of the isolated structure compared to the fixed-base structure. Mathematical models for the key response parameters are established via MRA. The MRA models produced acceptable results with significantly less computation. This is demonstrated via a practical example of how the MRA models would be incorporated in the design process, especially at the preliminary stages.

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 Dynamic Analyses of Isolated Structures under Bi-Directional Excitations of Near-Field Ground Motions

2012 ◽  
Vol 19 (4) ◽  
pp. 505-513 ◽  
Author(s):  
Gokhan Ozdemir ◽  
Ugurhan Akyuz
Keyword(s):  
Near Field ◽  
Soil Condition ◽  
Lateral Force ◽  
Isolation System ◽  
Wide Range ◽  
Dynamic Analyses ◽  
Lead Rubber Bearings ◽  
Rc Building ◽  
Orthogonal Components ◽  
Rubber Bearings

Nonlinear response history analyses (NRHA) of a 3-story isolated reinforced concrete (RC) building are carried out under both uni- and bi-directional earthquake excitations of near-field records. NRHA are conducted for a wide range of yield strength (Q/W) of lead rubber bearings (LRB), and isolation period (T). Selected near-field records are used to investigate both the contribution of orthogonal components on maximum isolator displacements and accuracy of equivalent lateral force (ELF) procedure on estimation of maximum isolator displacements. Analyses results show that both the contribution of orthogonal components and accuracy of ELF procedure depend on the soil condition where isolation system is implemented.

scholarly journals Seismic isolation system of two hinged arch suspended-deck bridge: a case study on Kalikuto bridge - Indonesia

2020 ◽  
Vol 156 ◽  
pp. 05024
Author(s):  
Tri Suryadi ◽  
Arvila Delitriana ◽  
Zdenek Fukar ◽  
Rusri Tjendana
Keyword(s):  
Seismic Isolation ◽  
Performance Tests ◽  
Isolation System ◽  
Expansion Joints ◽  
Lead Rubber Bearings ◽  
Design Requirements ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

Seismic isolation systems are widely used in buildings, bridges, and industrial structures all over the world. The system is known for the efficiency to reduce earthquake demand and thus provide better seismic performance of the structures. In particular to application in an arch suspended-deck bridge, seismic isolation system can be a solution for the seismic resisting system due to the incapability of the cable hangers to transfer horizontal forces from excitation mass on the hanging deck to the main compression arches. Kalikuto arch bridge that is built in 2018 has implemented both Lead Rubber Bearings and Seismic Rubber Expansion Joints as the part of its seismic resisting system. These two seismic isolation devices were designed and engineered accurately to fulfil the seismic design requirements of the Kalikuto bridge. Finally, several performance tests were conducted to evaluate the design compliance of the manufactured devices.

Research on the Effect of Combined Seismic Isolation System

2012 ◽  
Vol 446-449 ◽  
pp. 3299-3303
Author(s):  
Xi Sen Fan ◽  
Ting Lei Tian
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Seismic Responses ◽  
Combined System ◽  
Isolation System ◽  
Lead Rubber Bearings ◽  
Base Isolation System ◽  
Rubber Bearings ◽  
The Relationship

The isolation system between the upper structure and the foundation could reduce the seismic response of the former. A system combined of sliding and lead rubber bearings (LRB) is more effective in seismic isolation than using the later alone. In this research, the seismic responses of a building which was set with LRB and a combined system (the proportions between the sliding and LRB were 1/6, 1/4 and 1/3) respectively were analyzed and compared to that of the building without base isolation system to investigate the effect of seismic isolation. The relationship between isolation coefficient and the proportion of bearings was studied. The results show that the combined system could reduce the seismic response of structure, and it is more effective in seismic isolation if the leading bearing is relatively more.

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.

scholarly journals The seismic isolation of Wanganui Hospital with RoGliders

2008 ◽  
Vol 41 (4) ◽  
pp. 263-265
Author(s):  
W.H. Robinson ◽  
C.R. Gannon
Keyword(s):  
Seismic Isolation ◽  
Seismic Protection ◽  
Restoring Force ◽  
Maximum Displacement ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
New Buildings ◽  
Horizontal Displacements

Two new buildings at Wanganui Hospital, a peri-operative facility and an acute services block, have just been completed in June 2008 using RoGliders to provide seismic isolation in this earthquake prone region. This is the first application of the RoGlider, an isolator suitable for light structures providing in one compact unit the functions of support, damping and the required restoring force, while providing for a maximum displacement of ± 400 mm. The RoGlider provides for economical seismic protection under conditions not suitable for lead rubber bearings i.e. a combination of light vertical loads and large horizontal displacements.

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