考虑温度和剪切变形的改进型波形钢腹板组合箱梁动力特性研究

Dynamic characteristics of an improved composite box girder with corrugated steel webs considering temperature and shear deformation

为了精确分析温度效应和剪切变形效应对改进型波形钢腹板组合箱梁自振特性的影响,提出一种考虑温度效应和剪切变形效应的改进型波形钢腹板组合箱梁自振特性分析方法。综合考虑温度、剪切变形和波形钢腹板刚度修正的影响,运用应力等效原则推导出改进型波形钢腹板组合箱梁的自振频率解析公式;利用实桥ANSYS有限元分析结果和试验实测结果对自振频率解析公式的正确性进行了验证;分析了温度等效轴向偏心力变化、弹性模量变化、剪切变形效应、不同高跨比和不同宽跨比下温度效应对该桥型自振频率的影响。结果表明:温度效应对改进型波形钢腹板组合箱梁的基频影响较大,计算该桥型的基频时需要考虑温度效应的影响;波形钢腹板的剪切变形效应对该桥型自振频率的影响较为显著,从第4阶自振频率开始剪切变形的影响已超过50%;不同高跨比下温度效应对基频的影响较大,且随着高跨比的增大呈线性急剧增大;不同宽跨比下温度效应对自振频率的影响较小,可以忽略不计。研究成果可为改进型波形钢腹板组合箱梁的自振频率计算和分析提供参考依据。

In order to accurately analyze the influence of temperature and shear deformation effects on the natural vibration characteristics of the improved composite box girder with corrugated steel webs,a method for analyzing the natural vibration characteristics of an improved composite box girder with corrugated steel webs considering temperature and shear deformation effects is proposed in this paper.Considering the influence of the temperature,shear deformation and stiffness correction of the corrugated steel web,the analytical formula of the natural frequency of the improved composite box girder with corrugated steel webs is deduced by using the principle of stress equivalence;The correctness of the analytical formula of natural frequency is verified by using the AN-SYS finite element results and the measured results of bridge;The effects of temperature equivalent axial eccentric force,variation of elastic modulus,shear deformation,and temperature effect under different height-span ratios and different width-span ratios on the natural frequencies of bridge are analyzed.The results show that the fundamental frequency of the improved composite box girder with corrugated steel webs is greatly affected by the temperature effect,and the influence of the temperature effect needs to be considered when calculating the fundamental frequency of this bridge type;The shear deformation effect of the corrugated steel web has a significant influence on the natural frequencies of the bridge type,and the influence of shear deformation from the 4th order natural frequencies has exceeded 50%;Under different height-span ratios,the temperature effect has a greater influence on the fundamental frequencies,and it increases linearly and sharply with the increase of the height-span ratios;Under different widthspan ratios,the temperature effect has little influence on the natural frequencies and can be ignored.The research results can provide a reference for the calculation and analysis of the natural frequencies of the improved composite box girder with corrugated steel webs.