摘要
为了明确不同荷载条件下单箱多室变宽度道岔连续箱梁桥的应力分布及剪力滞效应,首先采用数值方法,利用ANSYS建立考虑预应力以及各种荷载工况加载方式的三维实体单元模型,分析箱梁在不同荷载效应下应力分布和变形趋势;然后,选择箱梁顶底板不同部位16个应变测点,采用多通道数据采集仪分别同步实测满堂支架现浇、预应力张拉及成桥落架等施工阶段时箱梁应力,并与数值分析数据进行对比验证;在此基础上,利用数值模型对该单箱五室预应力混凝土道岔梁在列车活载作用下的横向和纵向剪力滞效应进行分析。研究表明,三维实体数值模型可得到不同荷载工况作用下单箱多室箱梁应力分布的精细结果,数值分析结果和应力实测数据都显示箱梁顶底板应力分布不均匀,有明显的剪力滞效应,且顶板剪力滞效应更显著;数值分析还显示,车辆布载方式影响剪力滞效应,剪力滞效应沿着纵桥向变化,剪力滞系数最大达1.074。研究结果表明,单箱多室箱梁设计中应充分考虑箱梁剪力滞效应影响,以确保桥梁结构设计安全。
In order to clarify the stress distribution and shear lag effect of a turnout continuous beam bridge with single-box multi-compartment variable-width under different load conditions,a three-dimensional solid element model considering prestress and loading cases was established by using ANSYS.The stress distribution and deformation trend of the box beam under different load effects were analyzed.16 strain measuring points at different parts of the top and bottom plates of the box beam were selected.The multi-channel data acquisition instrument was used to synchronously measure the stress of the box beam at the construction stages such as the cast-in-place of the full hall support,the prestressed tension and the stage of finished bridge.Results were compared with the numerical analysis data.On this basis,the transverse and longitudinal shear lag effects of the single-box five-cell prestressed concrete turnout beam under live load were analyzed by using a numerical model.The results show that,the three-dimensional solid numerical model can obtain the fine results of stress distribution of turnout continuous beam bridge with single-box multi-compartment variable-width under different load conditions.Both the numerical analysis results and the measured stress data show that the stress distribution of the top and bottom plates of the box beam are uneven.There is an obvious shear lag effect,and the shear lag effect of the top plate is significant.The numerical analysis also shows that,the vehicle load distribution mode affects the shear lag effect.The shear lag coefficient changes along the longitudinal direction of the bridge.The maximum shear lag coefficient is 1.074.Both numerical analysis and measured data show that the shear lag effect of box beam should be fully considered in the design of beam bridge with single-box multi-compartment to ensure the safety of bridge structure design.
作者
梁占旭
马海涛
薛晓凯
徐超峰
LIANG Zhanxu;MA Haitao;XUE Xiaokai;XU Chaofeng(Zhengzhou Branch of China Railway Engineering Design and Consulting Group Co.,Ltd.,Zhengzhou 450001,China)
出处
《铁道勘察》
2023年第2期87-92,共6页
Railway Investigation and Surveying
基金
中铁工程设计咨询集团有限公司科技开发计划重点课题(研-2019-60)。
关键词
城市轨道交通
箱形梁
连续梁
变宽度
空间力学分析
剪力滞效应
组合有限元
urban rail transit
box beam
continuous beam
variable width
spatial mechanics analysis
shear lag effect
combined finite element
