桥梁结构边界条件变异对固有振动特性的影响分析

ANALYSIS OF EFFECT OF BOUNDARY CONDITION CHANGES ON FREE-VIBRATION CHARACTERISTICS OF BRIDGE STRUCTURE

针对实际桥梁结构复杂的边界条件,分析其对结构固有振动特性的影响因素。采用解析的方法分析简支梁在纵向不同程度的约束效应,以及简支梁、连续梁支承处不同刚度弹性扭转约束对结构自振特性的影响,并提出利用有限元分析来考虑复杂结构的边界条件变异影响的方法。最后以重庆轻轨PC梁以及一中承式拱桥的实测及计算固有频率结果验证了实际边界条件变化对固有频率的显著影响。

The influential factors of complex boundary condition on free-vibration characteristics of real bridge structures are analysed.In the case of simply supported beam,the analytic method is used to demonstrate the effects of different extent of axial constraint on free-vibration characteristics.In the case of simply supported continuous beam,the effects of torsional constraint under different support stiffness on free-vibration characteristics are analyzed.The finite element method is put forward to examine the effects of boundary condition changes in complex structure.On the basis of the tested and calculated frequencies of PC beams on Chongqing light rail bridge as well as on a through arch bridge,the remarkable effects of boundary condition are verified.