凿孔叠合混凝土空心板加固方法研究

发布时间：2019-07-06 16:36

【摘要】：很多预制混凝土空心板由于在长时间的使用过程中未进行必要的维修和保养，出现了损伤甚至破坏，还有一部分空心板因使用功能发生改变导致承载力不足，，但建筑因为历史价值、地理位置等等因素无法拆除。如果原有构件的受力性能已经不符合现在的使用要求，则会严重威胁房屋的可靠性，因此需要通过加固处理来保证建筑物新的功能要求。而已有的加固方案不能够充分利用原有预制空心板，造成了浪费。本文针对受力性能达不到使用要求的预制空心板提出一种即经济又可靠的加固方案，名为“凿孔叠合空心板加固法”，即将原有预制空心板孔洞上方开凿凹槽，放入加固钢筋并浇筑一定厚度混凝土叠合层，该方法为本文首创，可以明显提高叠合面抗剪切能力。本课题首先进行了十一个试件的静力荷载试验，研究空心板采用“凿孔叠合”方法进行加固后的正截面承载力、抗裂及裂缝宽度、刚度等受力性能，分析了钢筋混凝土应变变化规律，记录了叠合面的破坏情况。之后，应用通用有限元分析软件abaqus分析不同种类加固空心板的受力性能、应力分布特点。最后，通过理论分析与试验、有限元分析综合比较，提出适用于该加固方案的计算方法、叠合面抗剪切能力分析方法以及构件在二次受力作用下的正截面承载力公式。结果表明：凹槽中混凝土很大程度的增强了叠合层的抗剪切能力，使得加固后构件的整体性能良好，加固后预制空心板正截面承载力、抗裂性能、刚度等受力性能均得到大幅度提高，《混凝土结构设计规范》（GB50010-2010）中正截面受弯承载力计算方法、最大裂缝宽度计算方法、受弯构件挠度验算方法完全适用于“凿孔叠合”混凝土空心板加固法，加固后构件可按等尺寸整浇构件进行计算。计算开裂弯矩时，规范公式中的截面抵抗拒及截面抵抗矩塑性影响系数应进行修正。
[Abstract]:Many precast concrete hollow slabs have been damaged or even destroyed because they have not been repaired and maintained for a long time, and some hollow slabs have insufficient bearing capacity due to the change of use function, but the buildings can not be demolished because of historical value, geographical location and other factors. If the mechanical properties of the original components do not meet the current requirements, the reliability of the building will be seriously threatened, so it is necessary to ensure the new functional requirements of the building through reinforcement treatment. However, the existing reinforcement schemes can not make full use of the original precast hollow plate, resulting in waste. In this paper, an economical and reliable reinforcement scheme is proposed for prefabricated hollow slabs whose mechanical performance can not meet the requirements of use, which is called "hole drilling hollow plate reinforcement method". That is, the original prefabricated hollow slab holes are cut in grooves, reinforced steel bars are added and a certain thickness concrete composite layer is poured. This method is the first in this paper and can obviously improve the shear resistance of the superimposed surface. In this paper, the static load tests of eleven specimens are carried out, and the normal section bearing capacity, crack resistance, crack width, stiffness and other mechanical properties of hollow slabs strengthened by "hole drilling superposition" method are studied. The strain variation law of reinforced concrete is analyzed, and the failure of the superimposed surface is recorded. After that, the mechanical properties and stress distribution characteristics of different kinds of strengthened hollow slabs are analyzed by using the general finite element analysis software abaqus. Finally, through the comprehensive comparison of theoretical analysis, test and finite element analysis, the calculation method suitable for the reinforcement scheme, the analysis method of shear resistance of superimposed surface and the formula of normal section bearing capacity of members under secondary stress are put forward. The results show that the shear resistance of the composite layer is greatly enhanced by the concrete in the grooves, and the overall performance of the strengthened members is good. The normal section bearing capacity, crack resistance and stiffness of the prefabricated hollow slabs are greatly improved. The calculation method of the bending capacity of the normal section and the calculation method of the maximum crack width in the Code for Design of concrete structures (GB50010-2010). The deflection checking method of bending members is completely suitable for the reinforcement method of "drilling and superimposed" concrete hollow slabs, and the strengthened members can be calculated according to the equal size cast-in-place members. When calculating the cracking moment, the plastic influence coefficient of section resistance rejection and section resistance moment in the code formula should be modified.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU37;TU746.3

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