高墩大跨弯连续刚构桥冲击系数计算公式

Dynamic load allowance formula of long-span continuous curved rigid frame bridge with high piers

为研究高墩大跨弯连续刚构桥冲击系数敏感性因素及计算公式,以陕西某大跨弯连续刚构桥为依托,基于车-桥耦合振动原理,采用三轴五自由度车辆模型,分析了曲率半径、墩高和路面不平整度对桥梁结构最不利断面冲击系数的影响,给出了相应的挠度、弯矩和扭矩冲击系数最大值包络曲线,通过回归分析提出了弯连续刚构桥冲击系数的计算公式,并将计算结果与国内外规范进行比较.结果表明,对于此类特殊桥梁结构,中国规范冲击系数计算值较其他国家规范值小,在路面等级较差时,各国规范冲击系数计算值均偏于不安全,此时均需考虑不平整度对桥梁冲击系数的影响,研究结果将为该类桥梁冲击系数的精确计算提供参考.

In order to study the sensitive parameters of dynamic load allowance(DLA) for continuous rigid frame bridge with high pier and long-span and its calculation formulas,a rigid frame bridge in Shaanxi province was taken as example.Based on bridge-vehicle coupled vibration principle,the 5DOFs spatial vehicle model was setup,the effect of pier height,superstructure curvature radius and bridge deck roughness on the DLA of bridge structure was studied,and the maximum DLAs for the bending moment,deflection and torture moment were put forward.Then by regression analysis,the DLA formulas of the bridge were given,which were compared with those from other country's codes.The results show that for this special kind of bridge,the DLA from Chinese code is less than those of foreign countries.When exposed to the worse roads,all the current countries' codes underestimate the impact factor,so it is considerable that the roughness should be added to the DLA formulas.The results can give reference to computation method of DLA for this kind of bridge.