摘要
在钢锚梁-钢牛腿的组合索-塔锚固中,斜拉索水平分力主要由钢锚梁承担,竖向分力由钢壁板上的剪力连接件传递至混凝土塔壁承担。传统的组合索-塔锚固结合部多采用焊钉连接件,除了承受竖向剪力外,还会承受较大拉拔力,使塔壁产生拉应力进而降低组合索塔锚固区的耐久性和承载力。随着斜拉桥跨径的不断增加,要求组合索-塔锚固结合部具有更优越的抗拉拔性能以抵抗由于钢牛腿的偏心传力引起的顺桥向弯矩,具有更优越的竖向抗剪性能以均匀传递索力的竖向分力。为此,提出了一种可运用于钢牛腿支承型钢锚梁的新型箱格式连接构造,并开展了结合部1∶2缩尺模型试验,以研究新型箱格式连接的受力机理与承载性能。试验结果表明:斜拉索组合索-塔锚固箱格式连接具有较好的承载能力、刚度和抗裂性,在1.8P荷载作用时,除板件局部达到屈服强度外,其余钢结构和普通钢筋均处于弹性工作状态,承载性能良好,结构安全可靠;由于箱格式连接构造外面板对塔壁混凝土形成“套箍”作用,2.2P荷载作用下钢混最大脱离量仅约1.0 mm,最大竖向滑移量仅不到0.8 mm,说明结构具有良好的整体刚度;试件加载至2.5P时塔壁表面未出现明显开裂,表明新型钢箱格式连接构造具有较好的抗裂性,有利于提高组合索塔锚固结构的耐久性。
In the cable-pylon composite anchorage of steel anchor beam-steel bracket,the horizontal component of the cable force is mainly born by the steel anchor beam,while the vertical component is transmitted through shear connectors located on the steel wallboard to the concrete pylon.The conventional cable-pylon anchorage joint generally adopts stud connectors.In addition to bearing the vertical shear force,stud connectors also resist tension force,which could result in the tensile stress in pylon wall and decrease the durability and bearing capacity of the cable-pylon composite anchorage.With the increasing of the spans of cable-stayed bridges,the cable-pylon composite anchorage is supposed to possess better characteristics of tension resistance to resist longitudinal bending moments induced by the eccentricity of the steel bracket.Better characteristics of vertical shear resistance are also considered necessary to transmit the vertical cable force component uniformly.For this purpose,a new type of steel box joint,which could be used in the steel anchor beam supported by the steel bracket,is proposed.Furthermore,a 1∶2 scaled model test on the joint is conducted to research the stress mechanism and bearing capacity of the novel steel box joint.The test result shows that(1)This novel configuration possesses great bearing capacity,stiffness and crack resistance.Under 1.8P load,most steel parts and reinforcement bars are in elastic state except partial steel plates yielded,meaning the structure is reliable and obtained excellent bearing capacity.(2)The peak separation and slip between steel-concrete are only 1.0 mm and less than 0.8 mm under 2.2P load respectively.This might be resulted from the hoop effect on the concrete pylon wall induced by the outside plate of the steel box joint,indicating great overall stiffness of the structure.(3)When the load is increased to 2.5P,there is no obvious crack on the surface of concrete pylon wall,hence,this novel steel box joint showes great crack resistance and is favorable to i
作者
黄运林
刘明虎
刘玉擎
李修坤
贾伟
HUANG Yun-lin;LIU Ming-hu;LIU Yu-qing;LI Xiu-kun;JIA Wei(Hubei Shishou Yangtse River Highway Bridge Co.,Ltd.,Jingzhou Hubei 434400,China;CCCC Highway Consultants Co.,Ltd.,Beijing 100088,China;Tongji University,Shanghai 200092,China;Hubei Provincial Communications Investment Group Co.,Ltd.,Wuhan Hubei 430074,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2019年第11期68-74,共7页
Journal of Highway and Transportation Research and Development
