摘要
单塔单索面钢箱梁斜拉桥作为单线悬吊体系常用于交通量日益增大的市政宽体桥梁,但是该类桥型主梁宽跨比较大,需要充分考虑其空间力学行为特征才能在结构安全的前提下充分发挥其功能与景观的特性。以一座宽跨比为0.289的单塔单索面市政斜拉桥为例,首先从动力特性以及剪力滞效应角度对比了精细化三维空间模型与传统杆系梁格模型对该类桥型结构分析的准确性与适用性,推荐并使用精细化三维空间模型进行背景桥梁的空间效应分析,包括空间应力分布、局部构件受力以及偏载受力特性。分析结果表明:(1)纵、横向正应力沿截面横向均具有非常明显的分布不均匀现象,特别在一些复杂构造处,不均匀性更加明显;顶、底板均会表现出突出的剪力滞效应,有效宽度计算时需要考虑该效应。(2)局部构件受力同样具有强烈的空间性,最大值与最小值分布在不同位置,并且与主体结构应力分布相似。(3)偏载作用下,顶板应力水平会有明显提高,尤其偏载侧腹板位置,应力水平较高,偏载作用会进一步加剧顶板剪力滞的效应;偏载效应在底板处并不如顶板明显,仅在桥墩处表现出较强的剪力滞效应或应力不均匀分布特性。
The cable-stayed bridges with steel-box girder, single pylon, and single cable plane are usually applied for the city wide bridges with increasing traffic. Since the large ratio of width to span of the main girder, the spatial mechanical behavior of such bridges needs to be fully considered in order to demonstrate the characteristic of the function and city landmark in addition to the safety concern. Taking an urban cable- stayed bridge with single pylon and single cable plane for example, whose ratio of width to span is 0. 289. First, from the viewpoints of dynamic characteristics and shear lag, a comparative study on the accuracy and applicability of the analysis between the meticulous 3D model and traditional grillage beam model is conducted. The meticulous 3D model is suggested to analyze the spatial effect of the selected bridge, including spatial stress distribution, local component stress analysis and eccentric load condition. The analysis result shows that （ 1 ） The non-uniform distributions of longitudinal and transverse stresses along the transverse direction of section is very obvious, especially at some complicated structures. The shear lag effects, which are observed on the top and bottom plates, also need to be considered during the calculation of effective width. （2） The mechanical behavior of local components also has obvious spatial character, wherethe maximum and the minimum stresses locate at different positions following the similar stress distribution of the girder. （3） The eccentric load would highly increase the stress on the top plate especially near to the web plate and aggravate the shear lag effect. However, the bottom plate has lower eccentric load effect than the top plate, except the positions above the piers which have relatively strong shear lag effect or non-uniform stress distribution.
作者
余郁
熊文
薛玉波
叶见曙
YU Yu;XIONG Wen;XUE Yu-bo;YE Jian-shu(Yangzhou Municpal Construction Department,Yangzhou Jiangsu 225000,China;School of Transportation,Southeast University,Nanjing Jiangsu 210096,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2018年第8期64-72,共9页
Journal of Highway and Transportation Research and Development
基金
中央高校基本科研业务费专项资金项目(2242016R30023)
江苏省建设系统科技项目(2015ZD58)
关键词
桥梁工程
空间效应
精细化数值分析
单塔
单索面
剪力滞
偏载
bridge engineering
spatial effect
meticulous numerical analysis
single pylon
single cableplane
shear lag
eccentric load
