Lead‑Core Rubber Bearings (LRB): A Proven Seismic‑Isolation Solution For Building Earthquake‑Resistance Protection

Lead‑Core Rubber Bearing (abbreviated as LRB) is a laminated rubber seismic‑isolation component. It is manufactured by high‑temperature vulcanization of alternating layers of natural rubber and thin steel plates. A vertical lead core is embedded in the centre of the bearing, with connecting steel plates fitted on its top and bottom for firm installation between the superstructure and sub‑foundation of buildings. It is a well‑established base‑isolation component widely adopted in high‑seismic‑intensity zones.

Under normal working conditions, the rubber‑steel composite structure steadily bears the vertical load of the building and resists displacement caused by wind loads and minor vibrations, ensuring regular operation of the structure. When an earthquake strikes, the rubber layers undergo horizontal shear deformation, extending the natural vibration period of the building to avoid frequency bands with concentrated seismic energy and reduce upward transmission of seismic force. The lead core in the centre produces plastic deformation, converting seismic kinetic energy into heat for energy dissipation. It integrates seismic isolation and energy‑dissipation functions without requiring additional dampers.

1. Integrated energy‑dissipation design: The built‑in lead core provides energy‑dissipation capacity with an effective damping ratio of 15%‑30%. It enables a simplified isolation‑system layout and convenient later‑stage operation & maintenance.
2. Stable vertical bearing capacity: Internal sandwiched steel plates restrict lateral expansion of rubber, delivering excellent compression‑resistance performance. It is suitable for a wide range of public buildings including multi‑storey buildings, hospitals, schools and data centres.
3. Mature and reliable technical system: With decades‑long verification by global engineering projects, LRB bearings have complete mechanical‑performance parameters and well‑defined design standards, lowering selection difficulty for structural engineers.

LRB lead‑core rubber bearings are extensively applied in crowd‑intensive or vital lifeline projects such as schools, hospitals, nursing homes, government office buildings, high‑rise residential buildings, museums and large exhibition halls, as well as infrastructure projects including bridges and substations. It is particularly ideal for projects on stable ground conditions requiring an isolation period of 1.5‑2.5 seconds.

Waterproof and anti‑corrosion protection shall be implemented at the bearing installation site. Before construction, bearing specifications such as diameter and lead‑core size shall be precisely determined according to the total building weight, target isolation period and local seismic parameters.