In order to solve the equivalent problem of designed earthquake-induced track geometric irregularities considering structural randomness,a numerical simulation model of high-speed railway track-bridge system was established.Based on the short-time Fourier transform and the hypothesis testing principle,designed earthquake-induced track geometric irregularities were constructed.The equivalent fitting models and equivalent amplitude response spectra of designed earthquake-induced track geometric irregularities were established.A method for correcting the equivalent amplitude response spectrum considering structural randomness was proposed,and the rationality of the equivalent method for designed earthquake-induced track geometric irregularities was evaluated by comparing to measured geometric track irregularities after earthquake.Analysis results show that the fitting errors of designed earthquake-induced track geometric irregularities can be controlled below 10％under different pier height conditions by the combination of sine function and linear function.When the correction coefficients under seismic fortification and rare earthquakes are set to 3.0 and 1.5,the applicability of the modified fitting model obtained by multiplying the equivalent fitting model and the correction coefficient to random structures can meet the requirements.There is not significant difference in the shape and amplitude of measured geometric track irregularities before and after earthquake,and the corresponding amplitude error of lateral vehicle body acceleration is less than 5％.When the earthquake intensity is low,train can operate normally without significant deceleration.Compared with the measured geometric track irregularities after earthquakes,designed earthquake-induced track geometric irregularities increase the amplitude of lateral vehicle body acceleration by nearly 50％,and the driving speed threshold after earthquake calculated based on designed earthquake-induced geometric track irregularities has a reasonable safety margin.The established equivalent method for designed earthquake-induced track geometric irregularities on high-speed railway bridges can provide a fast and accurate manual calculation method for determining the driving speed threshold after earthquake and earthquake-resistant design based on driving performance after earthquake.2 tabs,19 figs,36 refs.
bridge engineeringhigh-speed railwayspeed threshold after earthquaketrack irregularitystructural randomnessearthquake damagetraffic safety
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