Uzbekistan is extending Line 3 of the Tashkent Metro 11 km south to the new international airport. The route crosses the Chirchik fault trace and sits within 8 km of the epicentre of the 1966 M 7.0 earthquake that destroyed much of the old city. Designers therefore mandated that every station box and ventilation shaft be isolated with Friction Pendulum Seismic Isolation Bearing technology.

The Friction Pendulum Seismic Isolation Bearing is the only device that simultaneously meets the Uzbek seismic code’s displacement demand of ±350 mm and the strict fire-resistance rating for underground structures. Each Friction Pendulum Seismic Isolation Bearing is cast into a 1.2 m thick base slab under the platform level, creating a seismic gap that allows the entire station to slide as a rigid block while passengers remain unaware of the movement.

Construction sequencing is optimized for the tight urban corridor. After diaphragm walls are completed, a prefabricated Friction Pendulum Seismic Isolation Bearing raft is lowered by tower crane into the excavation. The bearing raft contains 36 individual Friction Pendulum Seismic Isolation Bearing modules, pre-aligned and welded to embedded plates. Once the raft is positioned, concrete is poured around it, encapsulating the Friction Pendulum Seismic Isolation Bearing in a corrosion-resistant shell.

Dynamic analyses by the Tashkent Institute of Railway Engineers show that when the design earthquake strikes, the Friction Pendulum Seismic Isolation Bearing reduces column shear by 85 % and eliminates uplift at escalator trusses. This performance margin convinced the Japan International Cooperation Agency to lower its loan insurance premium, saving the Republic of Uzbekistan US $11 million over the debt service period.

Looking ahead, the Friction Pendulum Seismic Isolation Bearing specification is being copied for the planned Fergana Valley high-speed rail line, proving that the Friction Pendulum Seismic Isolation Bearing is not a one-off luxury but a transport-sector standard for the entire region.