Dynamic response of the China Railway Track System Ⅲ slab track system on a bridge under multidimensional seismic actions
This study investigated the dynamic response characteristics of the China Railway Track System(CRTS)Ⅲ slab ballastless track system on bridges under multidimensional earthquakes.According to the finite element method and the beam-rail-slab interaction principle,we built a refined spatial coupling model of the CRTS Ⅲ slab ballastless track seamless line on a bridge.The two common seismic waves,the El-Centro wave and the Tianjin Ninghe wave,were used to analyze the stress and deformation laws of the system under the coupling action of multidimensional earthquakes and to explore the influencing factors of the stress and deformation.The results showed that the bridge track structure featured larger longitudinal and lateral displacements under the action of multidimensional waves from the earthquakes and that the longitudinal,vertical,and lateral stresses in the structure were larger than those under the action of one-directional wave earthquakes.Moreover,the distributions of the responding longitudinal stress and the corresponding longitudinal displacements of the track structures induced by the earthquakes were the same under the multidimensional coupling seismic excitation and longitudinal seismic excitation.The distributions of longitudinal stress and the displacements of the track structures were the same under multidimensional seismic excitation and longitudinal seismic excitation of the same seismic wave.As for the midspan,the stress-distance graphs of the rail were all distributed antisymmetrically.The stress and deformation curves of the structures were distributed axially symmetrical for the longitudinal direction of the bridge.The displacement of the track slab,the concrete layer,and the base slab changed in a step-like manner with the increase or decrease in bridge spans,and the maximum values occurred in the middle of the model span.The relative displacements of the rail and track slab were maximum at the rightmost beam joint.The use of low-resistance fasteners can reduce the stress on the rails and the fixed support piers/platform tops under the action of earthquakes,but it will increase the relative longitudinal displacement of the rail and the slab.Therefore the resistance of the fasteners on the bridge should not be less than 10 kN for each pair.Moreover,to ensure the safety of high-speed trains on the bridge under an earthquake and ensure that each component does not suffer large displacements,the longitudinal stiffness of the fixed bearing piers/platform tops on the bridge should not be less than 1.0 times the coefficient value.
seismic actionCRTS Ⅲ slab trackCWR on bridgeuniform excitationdynamic response
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