公路桥梁水下结构加固技术研究

发布时间：2018-02-22 03:17

本文关键词： 桥梁加固不排水加固不分散混凝土纤维网格 FRP-钢复合管　出处：《南京林业大学》2015年硕士论文　论文类型：学位论文

【摘要】：由于上部荷载、水流及其它环境作用等,桥梁水下混凝土结构的病害往往较为严重且难以被发现,传统加固技术需要设置围堰等大型临时设施,施工费用高,社会影响大,鉴于此,本文以不排水加固为指导思想,开展了水下混凝土结构加固技术的相关研究。利用带有预制裂缝的圆柱形混凝土试件,在试验室水箱中模拟水下混凝土裂缝灌注,试件轴向抗压试验结果显示水下裂缝修补试件的破坏属于内聚破坏,极限荷载超过对比试件5.79%;利用带有预制缺陷的圆柱形混凝土试件,在水箱中对其灌注水下适用的环氧树脂,试件轴向抗压试验结果显示经过加固的缺陷试件抗压强度超过对比试件16.8%;在水箱中对混凝土试件进行模拟植筋施工,拉拔强度试验显示各试件的植入钢筋均被拔出,据此分析了钢筋直径、孔深对极限荷载、粘结强度的影响;在水箱中浇筑混凝土抗压强度标准试件,力学试验结果表明不分散混凝土水陆强度比能达到82%,可以满足水下施工的需求。通过对空间曲面纤维网格加固水下混凝土结构技术的研究,在试验室制作出小尺寸异形构件加固所需的空间曲面网格制品,提出了相关制作工艺,试件抗拉试验结果表明该制品力学性能相对稳定,能够满足加固施工的需求。同时,利用空间网格制品配合水下不分散砂浆对水下混凝土结构进行模拟加固施工,提出了空间网格加固水下混凝土结构的相关工艺,试件轴向抗压试验结果显示,该工艺能在不排水的条件下对小尺寸异形结构进行加固,显著提高水下混凝土结构的承载能力,并根据试验结果推导出相关承载能力计算模型。提出了FRP-钢复合管加固桥梁水下结构的技术工艺,并对其反力点的设置进行了专门研究,给出了反力点的设计方法;通过对复合管-土层相互作用的研究,分析了复合管竖向承载力的构成,同时利用有限元软件模拟了复合管的压入过程,对比不同的管径、壁厚、摩擦系数条件下静压力的变化,并据此给出了静力压入施工的相关建议。
[Abstract]:Because of the upper load, water flow and other environmental effects, the disease of underwater concrete structure of bridge is often serious and difficult to be found. Traditional reinforcement technology needs to set up large temporary facilities such as cofferdam, the construction cost is high, and the social impact is great. In view of this, this paper, taking undrained reinforcement as the guiding principle, has carried out the relevant research on the strengthening technology of underwater concrete structure. Using cylindrical concrete specimens with prefabricated cracks, the paper simulates the underwater concrete crack pouring in the water tank of the laboratory. The results of axial compression test show that the damage of underwater crack repair specimen is cohesive failure, and the ultimate load exceeds the contrast specimen 5.79. Using the cylindrical concrete specimen with prefabricated defects, the epoxy resin suitable for underwater is poured into the water tank. The axial compression test results of the specimens show that the compressive strength of the reinforced defective specimens is higher than that of the contrast specimens, and the concrete specimens are subjected to simulated reinforcement planting in the water tank, and the tensile strength tests show that all the steel bars implanted in the specimens are pulled out. The influence of the diameter and depth of steel bar on ultimate load and bond strength is analyzed, and the standard specimen of compressive strength of concrete is built in water tank. The results of mechanical tests show that the water-land strength ratio of non-dispersible concrete can reach 82.It can meet the requirements of underwater construction. The space curved mesh products for the reinforcement of small size special-shaped members are made in the laboratory, and the related fabrication techniques are put forward. The tensile test results of the specimens show that the mechanical properties of the products are relatively stable and can meet the needs of the reinforcement construction. In this paper, the underwater concrete structure is strengthened by using space mesh products combined with underwater non-dispersed mortar, and the related technology of strengthening underwater concrete structure with spatial grid is put forward. The results of axial compression test of the specimens show that, The technology can reinforce the small size special-shaped structure without drainage, and improve the bearing capacity of underwater concrete structure. Based on the experimental results, the calculation model of bearing capacity is deduced. The technical process of FRP- steel composite pipe strengthening bridge underwater structure is put forward, and the setting of reaction point is studied specially, and the design method of reaction point is given. Through the study of the interaction between composite pipe and soil layer, the vertical bearing capacity of composite pipe is analyzed. At the same time, the indentation process of composite pipe is simulated by using finite element software, and the wall thickness and diameter of composite pipe are compared. The change of static pressure under the condition of friction coefficient is given.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.72

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