Abstract
Abstract
Proposed article presents design procedure and dynamic analysis of a ballastless rail superstructure used to decrease the vibration from the moving trains in underground tunnels located adjacent to residential and commercial buildings. The rail superstructure features a floating slab consisting of a reinforced concrete (RC) slab with direct fixation of railway fastenings and elastomeric bearings, that transfer the loads from the floating slab to the tunnel casing. A track switch is mounted on a FST. The aim of the design procedure is to select required static and dynamic properties of elastomeric bearings made of cellurar polyurethane as well as the amount of reinforcement taking into account deteriorating properties of both materials. FE-model created in MSC Patran/Nastran software package is used to get an insight on stress-strain state of this floating slab track structure. Proposed FE-model consists of switch track with direct fixation railway fastenings, RC track slab, elastomeric supports. Static analysis is performed to get the upper-track structure elements’ deflections as well as stress-strain state of RC slab under moving trains. Dynamic interaction of the ballastless rail superstructure is investigated using derived from FE-analysis transfer-function between the superstructure and tunnel invert. Vibration isolation efficiency under excitation frequencies of moving trains over different speed is obtained from the transfer function.