波形腹板钢箱-混凝土组合梁桥的动力特性分析

Dynamic Characteristics Analysis of Box Girder Bridges with Corrugated Steel Webs

为计算波形腹板钢箱-混凝土组合梁桥的弯曲自振频率,以兰州景中高速机场连接线的某座装配式波形腹板钢箱-混凝土组合梁桥为工程背景,采用有限元数值模拟和现场试验的方法对其动力性能进行了研究。首先,运用ANSYS软件建立了波形腹板钢箱-混凝土组合梁桥的有限元模型,模型的正确性得到了现场试验的验证;其次,分析了该桥在不同参数影响下自振频率和振型的变化规律。结果表明:使用本研究建模方法建立的有限元模型可以精确地模拟实际桥梁结构;相较于K型和方钢型横联,工字钢型横联可以更好地提高桥梁的整体刚度;横隔板间距在规范要求的范围内对桥梁自振频率的影响较小;波形钢腹板的厚度对桥梁扭转自振频率影响较大,其次是弯曲自振频率;弯曲自振频率拟合公式计算值与ANSYS计算值的差值在0.23%~1.89%不等,精度较高。研究结果可为该型桥动力特性分析提供参考依据。

In order to calculate the bending vibration frequencies of box girder bridges with corrugated steel webs,and taking a prefabricated box girder bridge with corrugated steel webs in the connecting line of Jingzhong airport in Lanzhou as the engineering background,a finite element numerical simulation and field test methods are used to study its dynamic characteristics.First,the finite element model of box girder bridge with corrugated steel webs is developed by using ANSYS software.The correctness of the finite element model is verified by field tests.Subsequently,the change rule of natural frequencies and mode shapes of box girder bridge with corrugated steel webs are analyzed under the influence of different parameters.The results show that the finite element model can accurately simulate the actual bridge structure.Compared with K-type and square-type,an Itype external intermediate cross-frame system can better improve the overall rigidity of the bridge.Diaphragms spacing has little effect on the natural frequencies of the bridge within the range required by the specification.The thickness of corrugated steel webs have a great influence on the torsional natural frequencies of the bridge,followed by that of bending vibration frequencies.The difference between the calculated values of natural bending vibration frequency fitting formula and ANSYS is from 0.23%to 1.89%,respectively,and the former accuracy is high.The research results can provide a reference basis for dynamic characteristics analysis of box girder bridges with corrugated steel webs.