Floating slab track re-engineering: Experience drawn from a completely renovated FST damaged by major flooding in Sao Paulo Metro

Abstract

This paper describes the FST re-engineering of a Linha Leste track section in Sao Paulo Metro after major flooding in 2000 and the related experiences which have subsequently influenced novel design concepts. Due to major floods in the track section, excessive rail deflections and some fastening clip failures were noted, but while the floating slab track still provided the expected vibration isolation level the operational speed was reduced for safety reasons. The combination of the tunnel flooding and the pumping effect at rolling stock passage caused a migration of the elastic bearings under the slab track. After an intensive re-engineering program (including FEM simulations, material tests in harsh conditions, vibration and track stability measurements) a new FST system was installed in 2006 with easy to access and replaceable resilient strips, using the original concrete slabs. The work was carried out during the night-time maintenance window resulting in no disruption of traffic. This re-engineering experience has allowed us to understand the complex behaviour of FST in tunnels and to devise solutions for improving future FST design. © 2008 Springer-Verlag Berlin Heidelberg.