波形钢腹板箱梁桥内力重分布研究

发布时间：2019-01-22 20:22

【摘要】：波形钢腹板箱梁桥是一种新型的钢混组合结构,这种结构在工作时使波形钢腹板和混凝土充分发挥各自的特性,再加上体外预应力技术的使用,使得其受力特点有别于普通的预应力混凝土箱梁桥。本文通过对模型梁进行有限元建模,对其内力重分布问题进行了详细的分析计算。(1)根据以往学者们对波形钢腹板桥受力特点的研究结果,归纳总结了发展状况及受力特点。并对塑性内力重分布的概念、研究发展现状进行了阐述。对国内外规范及文献中关于弯矩调幅法、应力增量的计算进行了归纳。(2)对一个两跨连续梁从开始加载到破坏的全过程进行分析,阐述梁工作过程的三个阶段,将预应力混凝土连续梁的内力重分布概括为两个过程。结合文献对内力重分布的研究分析方法进行了总结,现有连续梁内力重分布的研究方法大致包括塑性铰法、变刚度法、全过程分析法以及弯矩调幅法。影响内力重分布的因素比较多,许多学者通过试验结合理论分析,主要与裂缝开展情况、预应力产生的次弯矩、塑性铰、斜截面承载能力以及无粘结筋的极限应力增量相关。(3)针对波形钢腹板箱梁桥阐述了使用ANSYS软件进行建模时模型、单元以及材料本构关系的选择。根据该种桥型的特点及模拟目的,使用弥散裂缝模型,主要用于得到结构的荷载位移特性曲线。基于APDL语言实现波形钢腹板建模,以一跨简支梁为例,给出了建模程序命令。(4)建立简支试验梁的分离式计算模型并进行极限承载状态的有限元分析,探讨在集中荷载作用下,波形钢腹板简支梁从加载、屈服到失效的全过程。由有限元计算结果可以看出,本文数值计算结果可以很好的体现波形钢腹板组合梁三折线的工作特征。列出体外预应力筋应力和跨中挠度数据并拟合曲线,结果证明应力增量和跨中挠度基本呈直线关系。(5)以2×40m的连续梁为模型梁,普通钢筋的配筋率为变量,分析在集中荷载作用下跨中位置的荷载位移曲线、体内预应力筋和体外预应力筋的荷载应力曲线,定性分析了普通钢筋配筋率对连续梁极限承载能力的影响。由负弯矩区处的应力荷载曲线,分析了不同配筋率下内力重分布的规律。给出了不同配筋率时跨中体外预应力筋应力增量与跨中挠度数据和曲线,分析了普通钢筋配筋率对应力增量的影响。最后,给出连续梁从加载至破坏过程中的弯矩调幅系数以及模型梁的极限承载力,并给出弯矩调幅系数随着配筋率的增大而减小的原因。
[Abstract]:The corrugated steel web box girder bridge is a new type of steel-concrete composite structure, which makes the corrugated steel webs and concrete give full play to their respective characteristics while working, plus the use of external prestressing technology. The mechanical characteristics of prestressed concrete box girder bridge are different from that of ordinary prestressed concrete box girder bridge. In this paper, the finite element model of the model beam is modeled, and the redistribution of internal force is analyzed and calculated in detail. (1) according to the research results of the previous scholars on the stress characteristics of the corrugated steel web plate bridge, The development and stress characteristics are summarized and summarized. At the same time, the concept of plastic internal force redistribution and the present situation of research and development are expounded. The calculation of moment amplitude modulation method and stress increment in domestic and foreign codes and literatures are summarized. (2) the whole process from loading to failure of a two-span continuous beam is analyzed, and the three stages of beam working process are expounded. The internal force redistribution of prestressed concrete continuous beam is summarized as two processes. This paper summarizes the research and analysis methods of internal force redistribution in continuous beams, which include plastic hinge method, variable stiffness method, whole process analysis method and moment amplitude modulation method. There are many factors that influence the redistribution of internal force. Many scholars combine theoretical analysis with experiments, mainly with crack development, secondary moment produced by prestress, plastic hinge, The bearing capacity of oblique section is related to the ultimate stress increment of unbonded steel bars. (3) the modeling model, the choice of constitutive relation of element and material for corrugated steel web box girder bridge using ANSYS software are described. According to the characteristics of the bridge type and the purpose of simulation, the dispersion crack model is used to obtain the load-displacement characteristic curve of the structure. The modeling of corrugated steel web is realized based on APDL language. Taking a single span simply supported beam as an example, the modeling program command is given. (4) the separated calculation model of simply supported test beam is established and the finite element analysis of ultimate bearing state is carried out. The whole process from loading, yielding to failure of simply supported beam with corrugated steel web under concentrated load is discussed. From the results of finite element calculation, it can be seen that the numerical results of this paper can well reflect the working characteristics of three broken lines of corrugated steel web composite beams. The data of stress and mid-span deflection of external prestressed tendons are listed and the curve is fitted. The results show that the stress increment and mid-span deflection are basically linear relations. (5) taking 2 脳 40m continuous beam as model beam, the reinforcement ratio of ordinary steel bar is a variable. The load-displacement curves of the mid-span and the load-stress curves of the internal and external prestressing tendons under concentrated load are analyzed. The influence of the reinforcement ratio on the ultimate load-carrying capacity of continuous beams is qualitatively analyzed. Based on the stress-load curve at the negative moment region, the law of internal force redistribution under different reinforcement ratios is analyzed. The data and curves of stress increment and mid-span deflection of external prestressed tendons with different reinforcement ratios are given, and the effect of reinforcement ratio on stress increment is analyzed. Finally, the moment amplitude modulation coefficient of continuous beam and the ultimate bearing capacity of the model beam are given from loading to failure, and the reason why the moment amplitude modulation coefficient decreases with the increase of reinforcement ratio is given.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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