Retrofitting older buildings with seismic isolation rarely makes headlines, yet it is the fastest-growing segment of the earthquake-protection market in North America and Europe. Among the various base-isolation devices, the humble linear rubber bearing (LNB) is emerging as the unsung hero of this quiet revolution.
An LNB is a stack of natural-rubber sheets bonded to thin steel shims. Without a heavy lead core, it is lighter, cheaper and easier to slide into a cut made at column base than its high-damping cousins. Once installed, the bearing lengthens the building’s natural period, turning violent seismic jolts into slow, harmless drifts while still carrying full gravity load. The device is passive: no hydraulics, no power, no sensors—just vulcanised rubber working around the clock.
What excites owners is the math revealed in recent California and Italian case studies. Retrofit cost using LNBs came in well below comparable lead-rubber solutions, yet slashed peak accelerations dramatically and slashed expected annual loss by an even wider margin. Because LNBs are symmetrical in every horizontal direction, they are ideal for irregular historic masonry or mid-century concrete frames where torsion is a concern. Installation is surgical: crews jack a single bay, cut the column, insert the bearing, release the load and move on, allowing businesses to stay open during off-hours.
Durability is no longer a worry. Modern ozone-resistant compounds and hot-dip-galvanised plates give the bearings a lifespan measured in decades, matching current Eurocode and ASCE requirements. Maintenance is visual: if the cover rubber stays intact, the isolator is healthy.
For cities faced with thousands of pre-code schools, hospitals and apartment blocks, linear rubber bearings offer a pragmatic upgrade path: modest upfront cost, striking risk reduction and swift re-occupancy after the big one. In seismic resilience, retrofitting with LNBs is no longer an exotic option—it is simply smart economics.