钢管混凝土组合桁梁弯剪性能试验研究  

Experimental study on CFST composite truss girder under combination of bending and shear

作　　者：刘永健 马印平 周绪红[1,2] 王琨[3] LIU Yongjian;MA Yinping;ZHOU Xuhong;WANG Kun(School of Civil Engineering,Chongqing University,Chongqing 400045;Research Center for Steel Structure Engineering,Chongqing University,Chongqing 400045;School of Highway,Chang’an University,Xi’an 710064,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学钢结构工程研究中心,重庆400045 [3]长安大学公路学院,陕西西安710064

出　　处：《建筑结构学报》2023年第6期24-35,共12页Journal of Building Structures

基　　金：长安大学中央高校基本科研业务费专项资金(300102219310);国家自然科学基金项目(51738068)。

摘　　要：钢管混凝土组合桁梁是由钢管混凝土桁架和混凝土板组成,既有桁架结构受力特征,又受板桁组合作用及节点力学性能影响显著,受力机理复杂,破坏模式多样化。为对钢管混凝土组合桁梁承载力进行研究,采用跨中单点加载模式对8榀不同截面形式、剪跨比及板桁连接方式的组合桁梁及桁架进行模型试验,对板桁组合作用、弹塑性阶段内力分布以及节点对整体力学性能的影响进行研究。结果表明:板桁组合作用可显著降低与之相连弦杆的应力水平,改变试件的破坏模式,提高结构承载力和抗弯刚度;将组合桁梁的上弦杆和混凝土板视为组合上弦杆后,其杆件轴力分布与铰接桁架模型吻合较好。依据试件的破坏模式、承载力,考虑板桁组合作用对组合桁梁承载力的影响,完善并验证了组合桁梁承载力简化计算方法,在不同弯剪加载模式下该方法预测的破坏模式均与试验结果相符,受弯及受剪承载力计算结果精度较高。Concrete filled steel tubular(CFST)composite truss girder is composed of a CFST truss and concrete slab.The girder has mechanical behavior similar to truss structure and also influenced by the slab and the truss composite effect.Thus,the mechanism of the girder is complicated and the failure mode varies.In order to investigate the strength of the CFST composite truss girder,experiments on eight specimens with different sectional shapes,shear to span ratios and connection types between slab and truss were conducted.The composite effect,axial force distribution of elastic and plastic stages,and the effect of joints on overall mechanical behavior of the girder were investigated.The results indicate that the stress level of the top chord is reduced due to the composite effect,because of which the failure modes of the specimen are also changed and the strength and flexural stiffness of the girder are improved.The top chord and concrete slab of the girder can be seen as a composite top chord.Thus,the axial force distribution of the girder is closer to the pin-jointed truss model.The strength of the girder due to the composite effect was taken into consideration.The strength calculating approach of the girder was optimized and validated against the experiments based on the failure modes and strength of the specimens.The approach can be applied to different bending and shear loading modes and can also give reasonable predictions of the bending and shear strength of CFST trusses and composite truss girders.

关 键 词：钢管混凝土组合桁梁 静力试验 受弯性能 受剪性能 承载力 

分 类 号：U441[建筑科学—桥梁与隧道工程] TU317.1[交通运输工程—道路与铁道工程]