Floating slab design in the control of transit train noise and vibration

Abstract

Operational experience with underground or subway rapid transit systems has shown that vibration and noise from trains can and does create intrusion in buildings located close to the underground facilities. This intrusion is usually in the form of a low‐frequency (31.5–125‐Hz range) noise or rumble generated by the ground‐borne vibration from the subway trains. The use of floating slab trackbed supported on resilient elements intended to vibration‐isolate the slab from the subway structure has been determined to be effective in reducing the transmission of vibration and noise to the surrounding ground and nearby buildings. This paper presents information on the two types of floating slab trackbed, the continuous floating slab track support system and the discontinuous slab system, which have been designed and are under construction at the Washington Metropolitan Area Transit Authority (WMATA) and Toronto Transit Commission systems and are proposed for use by the Metropolitan Atlanta Rapid Transit Authority system. Some sections of continuous floating slab trackbed are already in service at WMATA and measurements of the reduction of noise and vibration achieved at the adjacent buildings are presented.