load bearing capacity of elastomeric pads depends on number of steel plated inside the pad.
For elastomeric bearing to function as a soft spring, the bearing should be allowed for bulging laterally and the compression stiffness can be increased by limiting the amount of lateral bulging. To increase the compression stiffness of elastomeric bearings, metal plates are inserted. After the addition of steel plates, the freedom to bulge is restricted and the deflection is reduced when compared with bearings without any steel plates under the same load. Tensile stresses are induced in these steel plates during their action in limiting the bulging of the elastomer. This in turn would limit the thickness of the steel plates. However, the presence of metal plates does not affect the shear stiffness of the elastomeric
bearings.
The steel reinforcement within elastomeric pads makes their behavior quite different from plain elastomeric pads. Steel reinforced elastomeric bearings have uniformly spaced layers of steel and elastomer. The bearing accommodates translation and rotation by deformation of the elastomer. Under uniaxial compression, the flexible elastomer would shorten significantly and sustain large increases in its plan dimension, but the stiff steel layers restrain this lateral expansion. This restraint induces a bulging pattern and provides a large increase in stiffness under compressive loads. This permits a steel reinforced elastomeric bearing to support relatively high compressive loads while accommodating large translations and rotations. The stress in the steel plates and the strain in the elastomer are controlled by the elastomer thickness and the shape factor of the bearing. Large rotations and translations require taller bearings. Translations and rotations may occur about either horizontal axes, thus these bearings are suitable for bridges where the direction of movement is not precisely defined.
- Badges
- Science method