预应力混凝土连续箱梁悬臂施工过程中的剪力滞效应研究
发布时间：2018-09-01 17:33
【摘要】：摘要：薄壁箱梁由于具有抗扭刚度大、自重轻、跨越能力大及施工方便等优点,在现代桥梁中得到广泛地应用,但薄壁箱梁存在剪力滞效应,对结构安全有影响。我国预应力混凝土连续箱梁桥大多采用悬臂施工法,施工过程中剪力滞效应突出,忽略施工过程中的剪力滞效应会使结构存在安全隐患。国内关于悬臂浇筑混凝土箱梁施工过程中梁体剪力滞效应的研究较少,本文针对这种状况开展试验与计算分析,主要研究内容如下： (1)在一座采用悬臂浇筑施工的预应力混凝土箱梁桥的一个截面的顶、底板设置多个应变传感器,监测施工中梁体自重、挂篮自重、混凝土浇筑、预应力张拉等工况下截面的应力。 (2)分析了不同工况下箱梁顶、底板实测应力沿横向分布情况,讨论了实测应力的剪力滞规律。 (3)采用空间有限元分析软件,模拟计算了箱梁顶底板应力在悬臂施工阶段的剪力滞效应,与实验数据进行了对比分析。 (4)采用空间有限元分析软件,模拟并分析了箱梁最大悬臂状态下沿桥梁跨度方向剪力滞变化情况,对剪力滞影响因素宽跨比进行深入探讨。 (5)实测并分析了环境温度变化引起的温度效应对剪力滞的影响。
[Abstract]:Abstract: Thin-walled box girder is widely used in modern bridges because of its high torsional stiffness, light deadweight, large span capacity and convenient construction, but the shear lag effect exists in thin-walled box girder, which has an impact on structural safety. The research on shear lag effect of cantilever concrete box girder in the construction process is less in China. This paper carries out the test and calculation analysis for this situation. The main research contents are as follows:
(1) On the top of one section of a prestressed concrete box girder bridge constructed by cantilever casting, a plurality of strain sensors are installed on the bottom plate to monitor the stress of the section under the conditions of girder weight, hanging basket weight, concrete pouring and prestressed tension.
(2) The transverse distribution of measured stress along the top and bottom of box girder under different working conditions is analyzed, and the shear lag law of measured stress is discussed.
(3) The shear lag effect of box girder roof and floor stress during cantilever construction is simulated and analyzed by using the spatial finite element analysis software.
(4) The variation of shear lag along the span direction of box girder under the maximum cantilever state is simulated and analyzed by using the spatial finite element analysis software, and the influencing factors of shear lag width-span ratio are discussed in depth.
(5) measured and analyzed the effect of temperature effect caused by environmental temperature change on shear lag.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445;U441.5
本文编号：2217889
[Abstract]:Abstract: Thin-walled box girder is widely used in modern bridges because of its high torsional stiffness, light deadweight, large span capacity and convenient construction, but the shear lag effect exists in thin-walled box girder, which has an impact on structural safety. The research on shear lag effect of cantilever concrete box girder in the construction process is less in China. This paper carries out the test and calculation analysis for this situation. The main research contents are as follows:
(1) On the top of one section of a prestressed concrete box girder bridge constructed by cantilever casting, a plurality of strain sensors are installed on the bottom plate to monitor the stress of the section under the conditions of girder weight, hanging basket weight, concrete pouring and prestressed tension.
(2) The transverse distribution of measured stress along the top and bottom of box girder under different working conditions is analyzed, and the shear lag law of measured stress is discussed.
(3) The shear lag effect of box girder roof and floor stress during cantilever construction is simulated and analyzed by using the spatial finite element analysis software.
(4) The variation of shear lag along the span direction of box girder under the maximum cantilever state is simulated and analyzed by using the spatial finite element analysis software, and the influencing factors of shear lag width-span ratio are discussed in depth.
(5) measured and analyzed the effect of temperature effect caused by environmental temperature change on shear lag.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445;U441.5
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