高速铁路大跨度桥梁涡激振动振幅限值研究

Study on Vortex-Induced Vibration Amplitude Thresholds of High-Speed Railway Long-Span Bridge

为研究适用于大跨度铁路桥梁的涡振振幅限值,基于我国现行铁路规范和养护维修规则中的相关规定,提出了基于车体加速度峰值及其变化率的铁路桥梁竖弯涡振振幅限值和基于车体加速度及最大倾角的扭转涡振振幅限值建议取值。经研究建议:①加速度峰值不超过0.4 m/s^(2);加速度变化率限值对于列车速度低于和高于300 km/h时分别取0.25 m/s^(3)、0.2 m/s^(3),取此两项指标计算的最小幅值作为竖弯振幅限值。②列车速度分别为250,300,350 km/h时,单位长度车体倾角限值分别取0.60‰,0.50‰,0.42‰rad;一线两股钢轨间的变形差限值在列车速度低于和高于250 km/h时分别取5 mm和4 mm;车体最大倾角不超过0.04 rad;取上述各项指标计算的最小幅值作为扭转振幅限值。对五峰山长江大桥的案例分析结果表明,本文建议的幅值限值考虑了大跨度铁路桥梁的行车特点和性能要求,相较《公路桥梁抗风设计规范》(JTG/T 3360-01—2018)的涡振幅值限值更为严格。

To study the amplitude thresholds of vortex-induced vibration(VIV)for long-span railway bridge,according to the relevant provisions in China′s current railway standards and maintenance rules,the vertical VIV amplitude thresholds of railway bridge were suggested based on the train peak acceleration and its time-varying rate,and the torsional VIV amplitude thresholds were suggested based on the train acceleration and maximum inclination.The study suggests:①the train peak acceleration is controlled within 0.4 m/s^(2);the acceleration rate thresholds are taken as 0.25 m/s^(3) for the case of train speed lower than 300 km/h,and 0.2 m/s^(3) for the others;the vertical VIV amplitude thresholds are determined by the minimum value calculated by the two indexes.②for the cases of train speed at 250,300,350 km/h,the maximum train inclination per unit length is taken as 0.60‰,0.50‰,0.42‰rad,respectively;the vertical deformation difference thresholds of two rails are taken as 5 mm and 4 mm for the train speed lower and higher than 250 km/h,respectively;the maximum train inclination is taken as 0.04 rad;the torsional VIV amplitude thresholds are determined by the minimum value calculated by the above mentioned indexes.The case study of Wufengshan Changjiang River Bridge demonstrates that the proposed method considers the traffic characteristics and performance requirements of long-span railway bridges,which specifies stricter VIV amplitude thresholds than the Wind Resistant Design Specification for Highway Bridges(JTG/T 3360-01-2018).