Analysis of track-bridge interaction for small radius curved bridges considering loading history
At present most of the research on track-bridge interaction considering loading history is focused on linear bridges,for curved bridges,especially those with small radius.There are relatively little research on track-bridge interaction.In this paper,the ideal elastic-plastic hysteresis resistance model was used to simulate the longitudinal resistance of the fastener.A three-dimensional finite element spatial mechanics calculation model of rail-bridge-pier was established using finite element software with the Chengdong Special Bridge as the research object.The effect of curve radius on the track-bridge interaction was investigated.The track-bridge interaction of the curved bridge under multiple load coupling,reciprocal load and cyclic load considering the loading history effect was investigated.The concepts of"tension percentage"and"pressure percentage"were proposed to analyze the influence of curve radius on the error of conventional linear superposition method.The results show that the track-bridge longitudinal and lateral interactions in curved bridges are positively and inversely proportional to the curve radius.The relevant data changes are inversely proportional to the curve radius and converge basically when the curve radius exceeds 800 m.The simplified algorithm of"straight instead of curved"can be adopted at this time.The influence of curve radius on lateral track-bridge interaction is greater than that of longitudinal.The influence of curve radius on expansion and contraction is more significant than that of flexural and braking.Under multiple load coupling,the traditional linear superposition method is more conservative than considering the loading history and the temperature load is the main contribution.Considering the loading history,the rail will generate non-negligible residual internal force under reciprocating load,and the residual internal force under cyclic load will converge to that under the first reciprocating load.This is determined by the elastic-plastic hysteretic characteristics of the longitudinal resistance of the fastener.Linear superposition method error and curve radius has a correlation,compared to the flexural,braking conditions,expansion and contraction conditions are more sensitive to it.The results can provide reference for structural design of curved bridges considering loading history.
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维普
