特种车通过曲线部分斜拉桥的运营安全分析

1.长安大学 公路学院,陕西 西安 710064; 2.中交路技术有限公司,北京 100000; 3.广州大广高速公路有限公司,广东 广州 510000

桥梁工程; 曲线部分斜拉桥; 特种车; 安全系数; 塑性铰

Operational safety analysis of special vehicle driving through an extradosed bridge with curve shape
WANG Ling-bo1,JIANG Feng-wei1,2,ZHAO Guo-zhong3,HE Shuan-hai1

(1.Highway School,Chang'an University,Xi'an 710064,China; 2.Road and Bridge Consultants Co.,Ltd.,Beijing 100000,China; 3.Guangzhou Daguang Highway Co.,Ltd.,Guangzhou 510000,China)

bridge engineering; extradosed bridge with curve shape; special vehicle; safety factor; plastic hinge

DOI: 10.13800/j.cnki.xakjdxxb.2016.0222

备注

为研究曲线部分斜拉桥结构在超载运营时的安全状态,以某双幅部分斜拉桥为背景,采用基于空间结构有限元数值分析并考虑了计入配筋率的钢筋混凝土本构关系的方法,针对挂车-120车辆荷载,分别建立了单辆车、2辆车和3辆车以不同间距的单侧过桥模式,分析了桥梁结构首次出现开裂、截面首次进入塑性状态、单辆车通过时形成塑性铰直至结构形成机构而进入破坏阶段的全过程结构安全系数、索力分布及结构位移状况等主要力学参数,给出了结构受力特征及多辆车过桥时结构的安全系数与车辆间距的关系。研究表明,此桥在单侧通过1至3辆重120 t的挂车荷载时,其保证混凝土不开裂的最小安全系数在2.3以上,车辆沿内幅桥通过时安全系数较高; 结构安全系数与车辆间距大致呈线性关系。曲线部分斜拉桥的破坏模式为加劲梁中跨跨中截面出现塑性铰并不断扩大、主墩底截面相继出现塑性铰而形成机构,最终丧失承载能力。当多辆特种车通过曲线部分斜拉桥时,部分斜拉索的索力可能会达到设计峰值,在运营管理中应给予重视。

In order to study the structural safety status in overload conditions of curve extradosed bridge,a double-amplitude extradosed bridge is analyzed based on FEA numerical methods,considering the effects of reinforced concrete constitutive relation,three unilateral bridge models are designed for single veihicle,double veihicles and triple veihicles with different spacing in Trailer-120 vehicle load.Main mechanical parameters are analyzed,such as first crack appears on bridge structure,cross section first goes into plastic,the safety factor for whole process from plastic hinge formed to the structure forming mechanism and finally stepped into damage stage when single vehicle passing by,cable force distribution and structural displacement.The structure features and the relationship between safety coefficient and vehicle spacing when more veihicles go through the bridge are put forward.The research shows that:firstly,when no more than three veihicles with 120 ton weight go through unilateral bridge,the minimum safety factor of concrete cracks is above 2.3,and safety factor incrases when veihicles passing along the inside of the bridge.Secondly,structure safety factor and vehicle spacing has linear relationship.Finally,structure destruction all happened when plastic hinge appeared and expanded in the midspan and main pier bottom sections in the stiffening beam,then lose the whole bridge bearing capacity.When three special cars go through the curve extradosed bridge,a part of cable force may reach the design peak,which should be given attention in operation management.