LRB is the elastomeric bearing to absorb and scatter the horizontal energy generated during earthquakes. LRB solves problems for temperature dependency, durability and repeated loads by inserting a leadcore into the bearing composed of rubber and steel plate.

Moreover, LRB improves functions of the elastomeric bearing by inserting Lead Protecting Rings.

LRB-S is a seismic isolation bearing inserting lead-tin alloy core in center of rubber bearing to improve core efficiency and reduce lead.

▶ CONCEPTS OF LRB, LRB-S

-For LRB and LRB-S a lead and lead-tin plug is inserted into the center of the elastomeric bearing to absorb and scatter the horizontal energy generated during earthquakes. 

-When earthquakes occurs, LRB can extend the eigenperiod of a bridge and reduce the horizontal power caused by the weight. It can be a guideline to economical lower structure designs.

▶ Features of LRB, LRB-S

-LRB can resist against short-term weights such as wind power or braking load by untilizing the elastomeric stiffness of lead. It has stability against all time weights. It easily adjusts to slow displacement such as temperture displacement and does not deliver large weights to the lower structure.

-By using the plastic deformation property of lead, it absorbs and scatters earthquakes energy.

-it can restore its original position after earthquakes are spopped. No additional repair or maintenance required.

-When the lead protection ring is inserted, it is possible to prevent the lead from protruding due to the normal force and shear deformation acting on the LRB.

-LRB-S performs seismic isolation functions effectively than existing products LRB due to higher yield strength of lead-tin alloy core than lead core.

▶ Re-crystallization characteristic of lead molecular

-Metal deforms plastic deformation with absorbing energy with non linear characteristic.

At this time, structure of molecular lost its origin characteristic with broken. But lead molecular in rubber bearing can re-crystallize at room temperature to origin molecular.

With this characteristic, lead rubber bearing can restore bridge superstruvture to origin position after earthquake.

Also lead can use permanently with restoring itself to origin molecular at room temperature.

▶ Applicability of LRB, LRB-S 

-It can be applied to concrete bridges and steel bridges both. 

-It is applicable for long span bridge with excellent damping fuction and controlling displacement.

-It is suitable for existing bridge maintenance which has not conducted seismec design, not additional reinforcement.

-Early stiffness of lead suppresses shaking of bridges and is suitable for bridges with large short-term loads.