钢—混组合梁负弯矩区抗、阻裂方法研究

发布时间：2018-04-23 14:45

本文选题：钢-混组合梁 + 负弯矩区　；参考：《重庆交通大学》2015年硕士论文

【摘要】：钢-混组合连续梁桥在中间支座处有较大的负弯矩,混凝土桥面板因承受较大的拉应力,易出现开裂问题。混凝土板因开裂退出工作,使组合梁的刚度减小,组合效应减弱。倘若裂缝较大,有害物质会通过裂缝渗入到混凝土中,严重腐蚀、锈蚀钢筋,降低组合梁的耐久性,增加维护养护工作的困难。因此,在负弯矩作用下,对于研究连续混凝土板裂缝的发展、分布规律、控制方法和连续组合梁的承载能力、滑移效应是非常有必要的。本文依托港珠澳大桥浅水区非通航孔桥为工程背景,对钢-混组合梁负弯矩区的抗阻裂的方法进行了研究:①介绍了钢-混凝土组合梁的发展概况、国内外对结构裂纹的研究现状。论述了微膨胀纤维混凝土、支点强迫位移法和张拉预应力钢束这三种阻裂方法,以港珠澳大桥为项目背景详细介绍了组合梁体系转换施工流程、顶落梁施工、桥面板组合等,着重阐述了顶落梁与张拉预应力的施工工艺、注意事项等。对体系转换做了整体的概括。②对顶升过程进行了有限元理论计算,对实测数据与有限元理论计算结果进行对比分析,对同步顶升施工过程起到了有效的控制作用。根据结构电算、实测数据分析得到顶落梁与张拉预应力两种阻裂方法的阻裂效果。③本文主要测试了港珠澳大桥钢主梁组合阶段到存梁阶段(四点支撑到两点支撑)、顶升回落阶段(体系转换阶段)两个工况的相对滑移。通过百分表测得了钢梁与混凝土翼缘板界面的滑移规律,通过振弦式传感器与应变片测得了应变规律。④通过体系转换阶段的桥面板挠度、应力、钢混相对滑移来进行分析并有效控制,并引出本文的创新点—含FRP阻裂增强层的混凝土结构。本文基于断裂力学原理,分析了FRP阻裂增强层的两条断裂力学机理,并得出FRP阻裂增强层的优势。实验室分别对粘贴FRP阻裂增强层试件素混凝土试件进行抗弯强度和受力性能的测定与对比分析,证明了FRP阻裂增强层具有较高的承载能力,含FRP阻裂增强层的小梁较素混凝土小梁的开裂荷载和极限承载能力都得到了极大程度的提高。
[Abstract]:The steel-concrete composite continuous beam bridge has a large negative bending moment at the middle support, and the concrete deck slab is prone to crack due to the large tensile stress. The stiffness of the composite beam is reduced and the combination effect is weakened due to the cracking of concrete slab. If the crack is large, the harmful material will seep into the concrete through the crack, corrode the steel bar seriously, reduce the durability of the composite beam and increase the difficulty of maintenance and maintenance. Therefore, it is necessary to study the development, distribution, control method and bearing capacity of continuous concrete slab under negative bending moment. In this paper, based on the engineering background of non-navigable bridge in shallow water area of Hong Kong-Zhuhai-Macao Bridge, the anti-crack resistance method of steel-concrete composite beam in negative moment region is studied. The development of steel-concrete composite beam is introduced at 1: 1. Research status of structural cracks at home and abroad. This paper discusses three kinds of crack resistance methods, such as micro-expansive fiber concrete, fulcrum forced displacement method and tensioning prestressed steel bundle. Taking the Hongzhou-Zhuhai-Macao Bridge as the project background, this paper introduces in detail the construction process of the system conversion of composite beam, the construction of roof and falling beam, the combination of deck and slab, etc. The construction technology and matters needing attention of jacking and falling beam and tensioning prestress are expounded emphatically. The transformation of the system is summarized as a whole. 2 the finite element theory calculation of the lifting process is carried out, and the comparison between the measured data and the calculated results of the finite element theory is carried out, which plays an effective role in controlling the construction process of the synchronous uplift. According to the structure calculation, In this paper, we mainly test the combination stage of steel main girder of Hongzhou-Zhuhai-Macao Bridge and the stage of saving beam (from four point support to two points support, rising down stage). 3. The result of the analysis of measured data shows that the crack resistance effect of two kinds of crack resistance methods of top fall beam and tensioning prestressing force is obtained in this paper. Relative slippage of two working conditions in the stage (system transition stage). The slip law of the interface between steel beam and concrete flange slab is measured by a percentile meter, and the strain law is measured by vibrating string sensor and strain gauge. The relative slip of steel concrete is analyzed and effectively controlled, and the innovative point of this paper is the concrete structure with FRP crack resistance and strengthening layer. Based on the principle of fracture mechanics, this paper analyzes the two fracture mechanics mechanisms of FRP anti-crack enhancement layer, and obtains the advantages of FRP anti-crack strengthening layer. The flexural strength and mechanical properties of the plain concrete specimens bonded with FRP crack resistant reinforcement layer were measured and compared in the laboratory, which proved that the FRP anti-crack strengthening layer has a higher bearing capacity. Compared with plain concrete trabeculae, the cracking load and ultimate bearing capacity of trabeculae with FRP anti-crack enhancement layer have been greatly improved.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.4

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