• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.4
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• pp.53-62
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• 1998

Experimental studies for the laminated elastomeric bearing and the lead-rubber bearing, those are often used to improve the seismic capacity of the structures recently, are conducted to evaluate the seismic capacity of the bearings. The shear stiffness of the bearings decreases as the shear strain amplitude or the constant axial load level increases, but not sensitive to the strain rates effect. Bearings are strong for the axial compression but weak for the axial tension.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.481-488
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• 1998

Elastomeric bearing is used as one of the most useful way for isolation structures, because the horizontal stiffness is much lower than the vertical stiffness. In the design criteria of Elastomeric bearing, the stability of the bearings is evaluated by shear strain due to compression, lateral displacement, and rotation. The question how soft rubber can sustain heavy structure is now able to be solved by Ultimate capacity test of Laminated Elastomeric Bearings, which results 1,200kg/$\textrm{cm}^2$ of the max. compressive stress and this shows what a sufficient safety factor Elastomeric bearing has !

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.136-143
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• 1998

Elastomeric bearing is used as one of the most useful way for isolation structures, because the horizontal stiffness is much lower than the vertical stiffness. The quality of Elastomeric bearing depends on the vulcanization procedure to manufacture, which produces the elasticity of the rubber from the compound of rubber and sulphur. The durability of Elastomeric bearing is affected by the deterioration due to ozone and ultra-violet attack. but the durability during the design life of bridges can be assured by the sufficient size of the bearing in spite of the deterioration in surface. In the design criteria of Elastomeric bearing, the stability of the bearings is evaluated by shear strain due to compression, lateral displacement, and rotation. The question how soft rubber can sustain heavy structure is now able to be solved by Ultimate capacity test of Laminated elastomeric Bearings, which results 1,200kg/$\textrm{cm}^2$ of the max. compressive stress and this shows what a sufficient safety factor Elastomeric bearing has!

• Structural Engineering and Mechanics
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• v.49 no.3
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• pp.395-410
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• 2014

Fiber Reinforced Elastomeric Bearings (FREBs) are a relatively new type of laminated bearings that can be used as seismic/vibration isolators or bridge bearings. In an unbonded (U)-FREB, the bearing is placed between the top and bottom supports with no bonding or fastening provided at its contact surfaces. Under shear loads the top and bottom faces of a U-FREB roll off the contact supports and the bearing exhibits rollover deformation. As a result of rollover deformation, the horizontal response characteristics of U-FREBs are significantly different than conventional elastomeric bearings that are employed in bonded application. Current literature lacks an efficient analytical horizontal stiffness solution for this type of bearings. This paper presents two simplified analytical models for horizontal stiffness evaluation of U-FREBs. Both models assume that the resistance to shear loads is only provided by an effective region of the bearing that sustains significant shear strains. The presented models are different in the way they relate this effective region to the horizontal bearing displacements. In comparison with experimental results and finite element analyses, the analytical models that are presented in this paper are found to be sufficiently accurate to be used in the preliminary design of U-FREBs.

• Structural Engineering and Mechanics
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• v.5 no.4
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• pp.451-469
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• 1997

Experimental work undertaken to investigate the behaviour of laminated elastomeric bridge bearings under compression and a combination of compression and shear or rotation has been reported on elsewhere. However, it is difficult to determine the state of stress within the bearings in terms of the applied forces or the interaction between the steel shims and the rubber layers in the bearings. In order to supply some of the missing information about the stress-strain state within the bearings, an analytical study using the finite element method was carried out. The available experimental results were used to validate the model after which the analyses were used to provide further information about the state of stress within the bearing.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.47-62
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• 1998

The laminated elastomeric bearing and the lead-rubber bearing were designed to isolate one bay-two story steel frame which is designed for only gravity load. The seismic performance is evaluated for the designed steel frame before and after application of these seismic isolators between the super structure and the foundation. These isolators can improve the seismic capacity of the steel frame. Especially, by inserting the lead plug into the center of the laminated elastomeric bearing, the initial stiffness of th bearing can be increased, thus rather large lateral displacement can be prevented under the frequent service lateral load. During the strong earthquake, yielding of the lead can increase the capacity of the energy dissipation.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.1-6
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• 2002

In order to study the characteristics of fiber reinforced bearing, the steel plates of laminated rubber bearing were replaced with fibers which have same effects of steel plates. The comparison of vertical test and horizontal test of laminated rubber bearing and fiber reinforced bearing shows that the effective damping of fiber reinforced bearing is higher than laminated rubber bearing. This result implies the high energy dissipation ability of fiber reinforced bearing under earthquake excitation. These fiber reinforced bearing can be applied to the low-coast building.

• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.313-323
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• 2022

Steel laminated elastomeric bearings are commonly used in bridge structures to control displacements and rotations and transfer forces from the superstructure to the substructure. Proper knowledge of design, fabrication and erection procedures is important to ensure stability and adequate structural performance during the lifetime of the bridge. Difference in elevations sometimes leads to large size gaps between the bearing and the girder which makes the grout thickness that is commonly used for leveling deviate beyond standards. This paper investigates the structural response of High Strength Fiber Reinforced Cementitious (HSFRC) thin plinths that are used to close gaps between bearing pads and precast girders. An experimental program was developed for this purpose where HSFRC plinths of different size were cast and tested under vertical loads that simulate bridge loading in service. The structural performance of the plinths was closely monitored during testing, mainly crack propagation, vertical reaction and displacement. Analytically, the HSFRC plinth was analyzed using the beam on elastic foundation theory as the supporting elastomeric bearing pads are highly compressible. Closed form solutions were derived for induced displacement and forces and comparisons were made between analytical and experimental results. Finally, recommendations were made to facilitate the practical use of HSFRC plinths in bridge construction based on its enhanced load carrying capacity in shear and flexure.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.402-406
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• 2000

Strain energy function of the isoprene rubber was accurately determined by the experiments of uniaxial tension, planar tension, biaxial tension and volumetric compression. Deformation behavior of alternatively laminated structure of elastomer and reinforced aluminium layers, was analysed by Finite Element method. As a result, Ogden strain energy function obtained from the experiments describes the hyperelastic characteristics of the rubber very well. The compressibility of the rubber reduces axial stiffness of the structure. The axial stiffness of alternatively laminated structure being larger than shear stiffness. Which enables the structure to be shear-deformed easily.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.3
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• pp.137-144
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• 2000

Judging from the occasional occurrences of minor and major earthquakes in Korean peninsula, it is generally considered that Korean peninsula is not located in safe zone from earthquake any more. The worldwide damages from earthquake in public buildings such as bridges are also urging the necessity for an appropriate earthquake proof action. The elastomeric bearings have been used in seismic isolation design of bridges. and elastomeric bearings are quite ideal ones which allow movement and rotation in all directions without restraining superstruture. Within the limits of this study on dynamic behavior of the LBR for seismic isolation design, the reaearch results revealed that the Laminated Rubber Bearing(LRB) is useful in bridges for seismic isolation design. In addition, the relationship between the shape factor and compressive strength is linear. It was also found that the compressive strength gets higher as the shape factor increases.