波形钢腹板连续箱梁桥振动频率的参数分析
Calculation and Study on Bending Vibration Frequencies of the PC Continuous Box Girder with Corrugated Steel Webs

为准确计算和分析波形钢腹板连续箱梁桥的弯曲振动频率，首先，运用能量变分原理和Hamilton原理，推导出波形钢腹板简支箱梁桥弯曲振动频率的计算公式；然后，在简支箱梁桥频率计算公式的基础上，根据连续梁自由振动的三弯矩方程，得到任意等跨等截面波形钢腹板连续箱梁桥弯曲振动频率的计算公式，该公式的正确性得到已建实桥频率实测值和Ansys三维有限元计算值的验证；最后，对波形钢腹板连续箱梁桥弯曲振动频率的影响参数进行了分析。研究结果表明，波形钢腹板剪切效应对波形钢腹板连续箱梁桥弯曲振动频率的影响较大，而其余参数对该桥型弯曲振动频率的影响较小，在实际工程中为了计算的简便性，可以忽略这些因素的影响。研究结论可为同类型桥梁的设计提供参考。
As a new type of steel-concrete composite structure, the prestressed concrete(PC) box girder with corrugated steel webs is widely used in box girder bridges all over the world. There were no bending vibration frequency formulas for this new type of structure in the current codes of China. In order to find the vibration frequency analytical formulas of the continuous composite box girder with corrugated steel webs, the governing differential equations and corresponding natural conditions of the bending vibration frequency were established by means of the energy variation principle and Hamilton principle. The bending vibration frequency formulas of the two-span continuous box girder with corrugated steel webs were obtained. In the formula, it was found that the influence factors of bending vibration frequency can be divided into three aspects: shear lag, shear deformation of corrugated steel webs, and the coupling relationship. Combined with the results of the finite element analysis and the indoor model test, the validity of the formulas were proven. The analysis results show that the effects of the coupling relationship and shear lag have low influences on the bending vibration frequency of the box girder with corrugated steel webs, while the shear deformation of corrugated steel webs has great influence.