摘要
为探究连续曲线双工字钢-混凝土组合梁桥在弯扭组合作用下的力学性能,设计了一座曲线半径为200 m,跨径布置为17.5 m+17.5 m的连续曲线组合梁桥模型,并进行了静载试验,包括两点偏心弹性加载及四点对称破坏加载。试验测试了模型桥荷载-挠度关系曲线,控制截面钢梁、桥面板及钢筋应变分布,记录了模型桥的破坏过程及特征荷载,混凝土桥面板裂缝分布及裂缝宽度。结果表明:对称荷载作用下,曲率效应使外弧侧结构受力更不利;加载截面、中支点截面钢梁翼缘屈服后,第2跨加载点外弧钢梁腹板发生剪切屈曲,截面塑性转动能力受到钢板局部屈曲的限制;中支点桥面板裂缝分布范围超过计算跨径±20%;模型桥第2跨外梁破坏后,其他结构仍能继续承载,内弧侧结构延性指标远小于外弧侧,模型桥横桥向具有冗余性;竖向荷载作用下,模型桥弹性阶段截面正应力主要由弯曲正应力和约束扭转翘曲正应力组成,此外,钢梁下翼缘存在额外的横向弯曲正应力;最后,给出了钢梁下翼缘横向弯矩简化计算方法,并基于Vlasov薄壁结构理论,提出了双工字钢-混组合梁桥约束扭转截面特性计算方法。
To investigate the mechanical behavior of a curved continuous steel-concrete composite twin I-girder bridge subjected to flexure-torsion combined action,a steel-concrete composite bridge model was designed with a curve radius of 200 m and a 17.5+17.5 m span combination.Static loading tests were performed,including two-point asymmetric loading in the elastic stage of the bridge model and four-point symmetrical loading to structural failure.The load-deflection relationship and strain development on the steel girders,bridge slabs,and reinforcements were measured at key sections.The failure process and characteristic load of the bridge model,crack distribution,and crack width of concrete slabs were also recorded.The experimental results show that,under the symmetrical loading,the outer structure carries more load owing to the curvature effect.After the flange of the key sections is yielded,the outer web at the second span loading section is buckled owing to shear,indicating that the plastic rotation capacity of the section is limited by the local buckling of the steel plate.The concrete slab at the mid-support section is cracked beyond±20%of the effective span.The inner structure continues to carry the load after the outer structure fails,and its ductility coefficients are significantly smaller than that of the other side,indicating that the bridge model is redundant in the lateral direction.Under the vertical load,the normal stress of the cross-section is primarily developed by vertical bending and non-uniform torsion.In addition,the bottom flange of steel girders is developed with normal stress caused by lateral bending.Finally,a simplified method for calculating the lateral bending moment of the bottom flange is provided.Based on Vlasov's thin-walled structure theory,formulas are provided for calculating the non-uniform torsional section properties of the steel-concrete composite twin I-girder bridge.
作者
封博文
刘永健
周绪红
邢子寒
范泉锋
崔晓晓
杨俊宇
FENG Bo-wen;LIU Yong-jian;ZHOU Xu-hong;XING Zi-han;FAN Quan-feng;CUI Xiao-xiao;YANG Jun-yu(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Research Center of Highway Large Structure Engineering on Safety,Ministry of Education,Chang'an University,Xi'an 710064,Shaanxi,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China)
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2023年第5期109-127,共19页
China Journal of Highway and Transport
基金
中央高校基本科研业务费专项资金项目(300102219310)
陕西省交通运输厅科研项目(17-14K)。
关键词
桥梁工程
弯扭组合作用
试验研究
钢-混凝土组合梁桥
曲线桥
约束扭转
bridge engineering
flexure-torsion combined action
experimental study
steel-concrete composite bridge
curved bridge
non-uniform torsion
