T字形钢箱梁异形块设计及空间受力特性研究  

Design and mechanical analysis of special T-shaped block of steel box girder

作　　者：刘建威 于鹏[1,2] 李德建 LIU Jianwei;YU Peng;LI Dejian(Changsha Planning&Design Institute Co.,Ltd,Changsha 410007,China;School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]长沙市规划设计院有限责任公司,湖南长沙410007 [2]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2018年第3期700-709,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51378504)

摘　　要：为全面掌握T字形钢箱梁异形块空间受力特性,以长沙市红旗路主线65号~68号墩钢箱梁异形块为例,对箱梁的截面总体布置、顶底板、横隔板及纵肋进行详细设计,并选用MIDAS/Civil考虑剪切变形的厚板单元,进行全桥空间精细化仿真建模,研究不同荷载工况下的结构位移、应力、支座反力、自振特性及局部屈曲情况,验证设计方案的合理性。研究结果表明:该桥位移、支反力不均匀现象明显,即使在恒载作用下,钢箱梁同一截面处的位移和支反力仍有较大差别;偏载作用下,这种效应更为显著;最不利工况组合下,钢箱梁最大Mises应力达到232.8 MPa,发生在66号墩b支座底板和加劲肋连接处,因此设计中应对支座处构件进行适当加强;局部轮压作用下,横隔板具有足够的安全系数,不会发生屈曲;采用钢筋混凝土桥面板能大幅增加异形钢桥的刚度,使荷载分配更为均匀。本文结果可供类似桥梁的设计计算作为参考。The special T-shaped block of steel box girder is suitable for the design of large transport hub,but there are inevitable errors when analyzing its mechanical performance by general beam element because of its changeable live load distribution and obvious spatial effect.In order to understand its spatial mechanical performance comprehensively,the T-shaped block of steel box girder on 65#~68#pier in the mainline of Hongqi Road in Changsha was taken as engineering background.The general layout of box girder section,the thickness of top and bottom plate,and the size of transversal diaphragm plate and longitudinal ribbed stiffener were detailed discussed and finally determined.Based on the thick plate element considering shear deformation in MIDAS/Civil,the whole bridge spatial FEM model was precisely established.By studying structure displacement,cross section stress,end reaction,natural vibration characteristic and local buckling condition under different load cases,the rationality of bridge design scheme was verified.The results show there are obvious uneven phenomenon in structure displacement and end reaction;the displacement and end reaction in the same cross section still have lagre differences even under the dead load and this effect becomes more significant under the offset load.Under the most unfavorable combination of load case,the maximum Mises stress of steel box girder is 232.8 MPa,which occurs along the boundary between the plate and the stiffener of 66#b bearing;it is suggested that the components near the bearing should be suitably reinforced in structure design.Under the action of local wheel pressure,the transversal diaphragm has sufficient safety coefficient and the local buckling will not occur;it also indicates that the reinforced concrete bridge deck can multiply increase the stiffness of special-shaped steel bridge because it makes the load distribution more uniform.The results also can provide reference for design and calculation of similar bridges in the future.

关 键 词：异形块 截面设计 空间效应 厚板单元 应力集中 局部屈曲 

分 类 号：TU338[建筑科学—结构工程] U441.5[建筑科学—桥梁与隧道工程]