冻融循环作用下钢筋混凝土梁承载力研究

发布时间：2018-04-27 04:09

本文选题：钢筋混凝土梁 + 冻融循环　；参考：《西安建筑科技大学》2015年硕士论文

【摘要】：冻融破坏是导致混凝土劣化最广泛和最普遍的形式之一,冻融循环作用使混凝土由表及里的形成损伤层,最终导致混凝土产生层状剥离破坏。处于北方寒冷地区的混凝土结构受到荷载和冻融的双重作用,结构与构件的承载能力、变形以及延性都将发生退化。论文开展了冻融循环作用下钢筋混凝土梁受弯以及受剪承载性能退化研究,对于冻融环境下混凝土结构耐久性评估具有重要的理论意义和实际意义。本文采用试验研究、理论分析与数值模拟相结合的研究方法,对冻融循环作用下钢筋混凝土梁的受弯和受剪承载力进行较为深入的研究。主要内容如下:(1)采用气冻气融模拟试验方法,开展了足尺钢筋混凝土梁的冻融耐久性试验,设计冻融循环次数依次为0次、50次、100次、150次,对遭受不同冻融循环次数的试验梁进行静力加载试验,分析了试验梁的受弯承载力随冻融循环次数的变化规律。(2)基于课题组得到的冻融后混凝土材性试验数据,拟合给出了冻融混凝土应力-应变全曲线上升段的控制参数a、下降段的控制参数b与冻融循环次数N的函数关系;将混凝土截面分为冻融损伤层与未损伤层两部分,利用应变协调的条件确定冻融损伤层与未损伤层的峰值应力、峰值应变。(3)利用ABAQUS有限元分析软件,将钢筋混凝土梁的混凝土截面分为冻融损伤层与未损伤层,对冻融循环作用下钢筋混凝土梁受弯承载力进行了数值分析,结合试验结果分析了钢筋混凝土梁的受弯承载力随冻融循环次数的退化规律;进一步对考虑剪跨比、配箍率、冻融循环次数三种因素的钢筋混凝土梁受剪承载力进行了数值分析,分析了钢筋混凝土梁的受剪承载力随冻融循环次数的退化规律;建立了受剪承载力退化模型,并对模型进行了验证。
[Abstract]:Freeze-thaw failure is one of the most widespread and most common forms of concrete deterioration. The freezing thawing cycle causes concrete to form a damage layer from the surface to the formation, which eventually causes the concrete to have layered dissection damage. The concrete structure in the cold region of the north is double loaded with load and freeze-thaw, the bearing capacity of the structure and components and the deformation of the concrete structure The study of the bending and shear bearing performance degradation of reinforced concrete beams under freeze-thaw cycle has important theoretical and practical significance for the durability evaluation of concrete structures under freeze-thaw environment. This paper uses experimental research, theoretical analysis and numerical simulation research method, The flexural and shear bearing capacity of reinforced concrete beams under freeze-thaw cycle are deeply studied. The main contents are as follows: (1) the freeze-thaw durability test of full scale reinforced concrete beams is carried out by the method of air freezing and thawing simulation test. The number of freeze-thaw cycles is 0 times, 50 times, 100 times and 150 times, and the different freeze-thaw cycles are subjected to different freeze-thaw cycles. The test beam of a number of test beams is subjected to static loading test, and the variation law of the flexural bearing capacity of the test beam with the freezing thawing cycle times is analyzed. (2) based on the data of the concrete property test after the freezing thawing of the project group, the control parameter a, the control parameter B of the descending section and the freezing and thawing cycle times are given by fitting the freeze-thaw concrete stress strain full curve rising section. The function relation of N is divided into two parts: the freeze-thaw damage layer and the undamaged layer. The peak stress and peak strain of the frozen and thawing damage layer and the undamaged layer are determined by the condition of strain coordination. (3) the concrete section of the reinforced concrete beam is divided into the freeze-thaw damage layer and the undamaged layer by using the ABAQUS finite element analysis software, and the freezing thawing and thawing of the concrete beam is divided into freezing thawing and thawing. The flexural bearing capacity of reinforced concrete beams under cyclic action is numerically analyzed. Combined with the test results, the bending bearing capacity of reinforced concrete beams is analyzed with the times of freezing and thawing cycles, and the shear bearing capacity of reinforced concrete beams, considering the shear span ratio, the stirrup rate and the freezing and thawing cycle times, is further analyzed. The degradation law of the shear capacity of RC beams with the number of freeze-thaw cycles is analyzed, and the shear bearing capacity degradation model is established, and the model is verified.

【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.1

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