【摘要】 薄壁箱型截面广泛应用于刚架桥、大跨连续梁和连续刚构桥,此类桥梁动力分析中存在明显的弯扭耦合振动特点。基于剪力柔性梁格理论提出了能够充分考虑薄壁箱梁的自由扭转刚度、约束扭转刚度和转动惯量的三梁式计算模型,推导了模型中各主梁截面特性和质量分布的计算公式,以及横梁刚度特性的计算方法。应用该模型对一座预应力混凝土刚架桥进行动力特性分析,考虑混凝土防撞护栏的对动力特性的影响。计算结果和实体有限元模型计算结果及现场动力特性试验的实测结果吻合良好,表明该分析模型是正确可靠的,计算效率高,应用范围广。更多还原

【Abstract】 Aiming at analyzing the distinct coupled flexural-torsional vibration characteristics of continuous and rigid frame bridges with thin-walled box girder,a triple-beam dynamic FEM model which can comprehensively consider the influence of free torsional stiffness,restraint torsional stiffness and rotational moment of inertia was presented based on shear-force-flexible grillage theory.The formulae for computing the sectional properties and mass properties of the main girders and the crossbeams were given.Then the dynamic characteristic analysis of two given rigid frame bridges were carried out using this model,the single beam model and the solid model respectively for comparison.The effect of the guard barrier was also analyzed.The results of the presented model were validated by that of solid model and the field test results.It indicates that the triple-beam model is practical and reliable with high computational efficiency.更多还原