钢-混凝土组合梁施工阶段钢梁稳定性实用计算方法及参数分析  

Practical Design Method and Parameter Analysis on Steel Beam Stability of Steel-concrete Composite Beam in Construction Stage

作　　者：成立涛[1] 郗磊[1] 魏学军 孙宁[1] CHENG Li-tao;XI Lei;WEI Xue-jun;SUN Ning(CCCC First Highway Consultants Co.,Ltd.,Xi'an Shaanxi 710049,China)

机构地区：[1]中交第一公路勘察设计研究院有限公司,陕西西安710049

出　　处：《公路交通科技》2023年第7期121-128,共8页Journal of Highway and Transportation Research and Development

基　　金：中交一公院科创基金项目(KCJJ2017-16,KCJJ2021-14)

摘　　要：为便于在钢-混凝土组合梁设计过程中,考虑主梁变截面、横梁刚度及各种复杂约束条件,简单准确地评估施工阶段钢梁的整体稳定性,在《公路钢结构桥梁设计规范》(JTG D64—2015)的框架下,参考BS EN 1993-1-1:2005和BS EN 1993-2:2006的相关规定,总结出了一套实用性强的钢梁整体稳定性验算方法。以跨径布置分别为4×30 m,4×35 m,4×40 m主梁形式的连续钢板组合梁为例,运用上述稳定性验算方法,研究了横梁间距、抗弯刚度对主梁施工阶段整体稳定性的影响。理论分析和数值计算结果表明:钢梁整体稳定性不仅与弹性屈曲系数相关,也与施工期间的钢梁应力值相关;对于大跨径桥梁,由于恒载占比相对小跨径桥梁更大,导致施工阶段稳定性验算工况应力水平较高,更容易发生施工阶段钢梁失稳,应特别关注加强验算和构造处理;为便于设计人员简化设计流程,提出了一个d类截面Q345材质钢梁整体稳定的充分不必要条件:线弹性屈曲系数>4且钢梁最不利应力值<117.9 MPa;主梁整体稳定性随横梁刚度增大而增大,随横梁间距减少而增大,但通过提高横梁刚度来提高主梁整体稳定性的效率不如减少横梁间距;大于受压翼缘宽度30倍的横梁间距不能保证施工阶段的钢梁整体稳定性,横梁间距宜根据稳定性计算确定。In order to facilitate the design process of steel-concrete composite beams and simply and accurately evaluate the overall stability of steel beams during construction stage,considering the variable cross-section beam stiffness and various complex constraint conditions of the main beam,a practical method for checking the overall stability of steel beams is summarized by referring to the relevant provisions in BS EN 1993-1-1:2005 and BS EN 1993-2:2006 under the framework of Specifications for Design of Highway Steel Bridge(JTG D64—2015).Taking the continuous steel plate composite beams with span layouts of 4×30 m,4×35 m and 4×40 m for examples,the influences of crossbeam spacing and bending stiffness on the overall stability of main beams during construction stage are studied by using the method mentioned above.The theoretical analysis and numerical calculation results show that(1)the overall stability of steel beams is not only related to the elastic buckling coefficient,but also to the stress value of the steel beams during construction period;(2)for long-span bridges,due to the proportion of dead load is larger than that of small-span bridges,the stress level in the stability checking calculation conditions during construction phase is higher,making it more prone to steel beam instability,therefore,special attention should be paid to strengthening the checking calculation and structural treatment;(3)in order to simplify the design process for designers,a sufficient and unnecessary condition for the overall stability of Q345 steel beams with d-section is proposed:the linear elastic buckling coefficient is greater than 4 and the most unfavorable stress value of the steel beam is less than 117.9 MPa;(4)the overall stability of the main beam increases with the increase of crossbeam stiffness and the decrease of crossbeam spacing,but the efficiency of improving the overall stability of the main beam by increasing the crossbeam stiffness is not as good as reducing the crossbeam spacing;(5)the crossbeam spacing g

关 键 词：桥梁工程 施工阶段稳定性 有限元分析 弹性屈曲分析 钢混组合梁 

分 类 号：U441.4[建筑科学—桥梁与隧道工程]