隔板式曲线组合梁施工阶段弯扭性能研究

发布时间：2018-03-25 07:17

本文选题：曲线组合梁　切入点：施工阶段　出处：《石家庄铁道大学》2014年硕士论文

【摘要】：曲线组合梁采用无支架施工时，混凝土的湿重完全由钢梁承担，使其在承受弯扭耦合作用的同时，还会由于刚度较小出现变形过大或压屈的危险。本文依托国家自然科学基金资助项目《隔板式曲线组合梁桥弯扭作用机理及横隔板影响效应研究》(51108281)，对采用横隔板作为横向联接系的曲线组合梁施工阶段的受力性能进行了试验研究和数值分析，主要工作和结论如下： (1)进行了6片简支曲线组合梁混凝土板浇筑阶段的静载试验，发现跨径比对弯矩影响很小，对扭矩影响较大，但横隔板数量对二者影响均较小，分段浇筑时的扭矩比整体浇筑时小。切向应变沿截面竖向符合平截面假定，沿截面横向在有隔板处直线形式变化，在无隔板处以两头大中间小的折线形式变化，但都表现为曲线外侧大内侧小； (2)试验结果和ANSYS有限元分析结果均显示，各向应变和位移均随跨径比的增大而增大，随横隔板数目、钢梁高度和横隔板厚度的增多而减小，整体浇筑时比分段浇筑时大。横隔板对钢梁腹板有明显的横向约束作用，端横隔板和跨中横隔板作用较大，横隔板超过5个后影响减小； (3)采用M/R法可较好地分析曲线钢梁的扭转效应。在分布扭矩作用下，竖向位移、径向位移、翘曲正应力、以及翘曲正应力与弯曲正应力的应力比均随跨径比的增大线性增大，随横隔板数目的增加和计算跨径的减小而非线性减小，说明跨径比是反映曲梁受扭程度的一种显性指标； (4)曲线组合梁施工阶段混凝土采用分段浇筑时，组合梁的各向位移和应力均比整体浇筑时小，说明钢梁与混凝土板之间存在早期组合作用；当曲线组合梁施工阶段分段浇筑时的时间间隔在0.25~7d，需要考虑早期组合作用而且要考虑随育龄期增长组合梁的受力特征；在钢-混凝土曲线组合梁混凝土板浇筑过程中，已浇好的节段必须考虑结合面相对滑移，，否则会引起较大的误差。
[Abstract]:When the curved composite beam is constructed without support, the wet weight of concrete is borne entirely by the steel beam, which makes it bear the coupling action of bending and torsion at the same time. This paper relies on the project supported by the National Natural Science Foundation < Research on the Mechanism of bending and torsion of curved Composite girder Bridges with diaphragm Type and the influence effect of Transverse diaphragm. The experimental study and numerical analysis of the mechanical behavior of curved composite beams during construction are carried out. The main work and conclusions are as follows:. 1) the static load tests of six simply supported curved composite beams and concrete slabs are carried out. It is found that span ratio has little effect on bending moment and great influence on torque, but the number of transverse diaphragm has little effect on both. The torsion moment of subsection pouring is smaller than that of integral pouring. The tangential strain along the section vertical conforms to the assumption of plane section, and changes along the cross section in straight line form where there is a partition. However, all of them showed that the lateral and medial side of the curve was small; 2) the results of test and ANSYS finite element analysis show that the strain and displacement increase with the increase of span ratio, and decrease with the increase of the number of transverse diaphragm, the height of steel beam and the thickness of transverse diaphragm. The transverse partition has obvious transverse restraint on the steel beam web, the end transverse partition and the span middle transverse partition have a greater effect, and the transverse diaphragm has less effect after more than 5 years. 3) the torsional effect of curved steel beams can be well analyzed by using M / R method. Under distributed torque, vertical displacement, radial displacement, warpage normal stress, and stress ratio of warpage normal stress to bending normal stress all increase linearly with the increase of span ratio. The ratio of span to diameter is a dominant index to reflect the torsion degree of curved beams. 4) the displacement and stress of the composite beam in each direction are smaller than that in the whole pouring stage when the concrete is used in the construction stage of the curved composite beam, which indicates that there is an early combination effect between the steel beam and the concrete slab. In the construction stage of curved composite beam, the time interval is 0.25 ~ 7 days, so it is necessary to consider the effect of early combination and the mechanical characteristics of composite beam with the increase of childbearing age, and in the process of concrete-slab construction of steel-concrete curved composite beam, it is necessary to consider the mechanical characteristics of the composite beam with the increase of childbearing age. The relative slip of the joints must be taken into account in the cast-in-place section, otherwise, there will be a large error.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.216

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