In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was establ...In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was established. Taking 32 m simply supported box beam bridge which is widely used in the construction of pas- senger dedicated line in China as an example, influences of the temperature variation between the bottom and top of the bridge, temperature curve index, type of temperature gradient, and beam height on track vertical irregularity were analyzed with the model. The results show that TDL has more effects on long wave track irregularity than on short one, and the wavelength mainly affected is approxi- mately equal to the beam span. The amplitude of irregu- larity caused by TDL is largely affected by the temperature variation, temperature curve index, and type of temperature gradient, so it is necessary to monitor the temperaturedistribution of bridges in different regions to provide accurate calculation parameters. In order to avoid the irregularity exceeding the limit values, the height of 32, 48, and 64 m simply supported box beam bridges must not be less than 2.15, 3.2, and 4.05 m, respectively.展开更多
我国快速发展的经济对铁路运输能力的要求不断提高,既有铁路重载扩能运输改造进程不断推进,随之提高的列车轴重必然会降低既有铁路桥梁的活载储备量,从而导致T梁的整体刚度和耐久性下降。通过对不同跨径桥梁活载储备量的计算分析,进而...我国快速发展的经济对铁路运输能力的要求不断提高,既有铁路重载扩能运输改造进程不断推进,随之提高的列车轴重必然会降低既有铁路桥梁的活载储备量,从而导致T梁的整体刚度和耐久性下降。通过对不同跨径桥梁活载储备量的计算分析,进而选取跨度12 m混凝土T梁作为研究对象进行静力适应性分析,对梁体跨中截面主筋应力、梁体跨中截面上翼缘混凝土压应力及梁体跨中底板裂缝宽度进行检算;并且建立动力有限元模型,分析不同列车荷载作用对跨中横向加速度及横向振幅的影响规律,并与试验实测结果进行对比分析。研究结果表明:在270 k N和300 k N轴重重载列车作用下,梁体受拉钢筋最底部主筋应力均超过容许值;结构动力响应随着车辆轴重增大而增大; 12 m跨低高度简支钢筋混凝土梁横向动力适应性优于普通高度简支梁,两者均满足开行大轴重重载货车要求。展开更多
基金supported by the National Science Foundation (U1234201)the Doctorial Innovation Fund of Southwest Jiaotong University
文摘In order to study the effect of temperature difference load （TDL） along the vertical direction of a simply supported beam bridge section on the vertical irregularity, a rail-bridge-piers calculation model was established. Taking 32 m simply supported box beam bridge which is widely used in the construction of pas- senger dedicated line in China as an example, influences of the temperature variation between the bottom and top of the bridge, temperature curve index, type of temperature gradient, and beam height on track vertical irregularity were analyzed with the model. The results show that TDL has more effects on long wave track irregularity than on short one, and the wavelength mainly affected is approxi- mately equal to the beam span. The amplitude of irregu- larity caused by TDL is largely affected by the temperature variation, temperature curve index, and type of temperature gradient, so it is necessary to monitor the temperaturedistribution of bridges in different regions to provide accurate calculation parameters. In order to avoid the irregularity exceeding the limit values, the height of 32, 48, and 64 m simply supported box beam bridges must not be less than 2.15, 3.2, and 4.05 m, respectively.
文摘我国快速发展的经济对铁路运输能力的要求不断提高,既有铁路重载扩能运输改造进程不断推进,随之提高的列车轴重必然会降低既有铁路桥梁的活载储备量,从而导致T梁的整体刚度和耐久性下降。通过对不同跨径桥梁活载储备量的计算分析,进而选取跨度12 m混凝土T梁作为研究对象进行静力适应性分析,对梁体跨中截面主筋应力、梁体跨中截面上翼缘混凝土压应力及梁体跨中底板裂缝宽度进行检算;并且建立动力有限元模型,分析不同列车荷载作用对跨中横向加速度及横向振幅的影响规律,并与试验实测结果进行对比分析。研究结果表明:在270 k N和300 k N轴重重载列车作用下,梁体受拉钢筋最底部主筋应力均超过容许值;结构动力响应随着车辆轴重增大而增大; 12 m跨低高度简支钢筋混凝土梁横向动力适应性优于普通高度简支梁,两者均满足开行大轴重重载货车要求。
