预应力混凝土梁灌浆密实度无损检测的研究

发布时间：2018-04-23 05:40

本文选题：波纹管 + 灌浆密实度　；参考：《东南大学》2015年硕士论文

【摘要】：随着我国经济的腾飞,我国的基础建设事业开始大踏步前进。在桥梁建设事业方面我国取得了长足的发展,各种大中型预应力混凝土桥梁先后落成,为我国社会主义交通的建设贡献了巨大的力量。但是与此同时各种问题开始显现,尤其是预应力桥梁中预应力筋的锈蚀问题,这造成了严重的桥梁安全隐患。经调查发现预应力筋锈蚀的最主要原因是波纹管内的灌浆不密实,因此寻找一种简单可靠的检测灌浆密实度的方法成了当下研究的热点问题。冲击回波法是一种利用瞬时冲击产生的应力波进行无损检测的方法,本文主要进行了利用冲击回波法检测波纹管灌浆密实度的室内试验和有限元仿真模拟研究,并开展了如下的研究工作：1.分析了冲击回波法检测的原理,并基于文献调研介绍了目前其在国内国际上的研究现状。2.基于室内试验,揭示了不同条件下混凝土试件回波信号的分布规律,进而分析了灌浆密实度、预应力筋、混凝土厚度及混凝土配筋等的影响。结果表明：(1)对于时域信号,预应力筋、混凝土厚度对其影响不大；(2)随着灌浆密实度的减小和配筋的添加,时域信号紊乱度增加；(3)对于频域信号,随着灌浆密实度的减小,主波峰频率减小；(4)混凝土厚度的增加使频域信号的频率全程减小；(5)当添加配筋和预应力筋后,波形信号分别出现杂波和低频率小峰值波峰。3.经过本文的ABAQUS有限元仿真,得知仿真结果与实验结果具有一致性。通过有限元软件ABAQUS来模拟利用冲击回波检测混凝土梁板内部的灌浆缺陷,并可以准确地定量地分析结构内部的缺陷率。4.基于有限元仿真对特定厚度下的灌浆波纹管在不同缺陷时的状态进行了模拟,发现在有限元中应力波的传播也遵从同样的规律。并且随着缺陷的增大而逐渐变化的仅仅是主峰的频率,总体上主峰频率随着缺陷的增大逐渐减小。然后本文对缺陷值与主峰频率值进行了定量化的分析,通过MATLAB软件拟合出了两者之间的函数关系式,并通过对比室内试验的数据反推出了室内试验情况下两者间对应的函数关系式。
[Abstract]:With the rapid development of our country's economy, our country's infrastructure construction enterprise begins to advance with great strides. Great progress has been made in the construction of bridges in China, and various large and medium-sized prestressed concrete bridges have been completed successively, which has contributed a great deal of power to the construction of socialist traffic in our country. But at the same time, various problems began to appear, especially the corrosion of prestressed tendons in prestressed bridges, which caused serious hidden dangers of bridge safety. It is found that the main reason of the corrosion of prestressed tendons is that the grouting in bellows is not dense, so it is a hot issue to find a simple and reliable method to detect the density of grouting. The impact echo method is a kind of nondestructive testing method by using the stress wave generated by instantaneous impact. In this paper, the laboratory test and finite element simulation study on the density of bellows grouting with impact echo method are carried out. And carried out the following research work: 1. The principle of Impulse echo detection is analyzed, and based on the literature investigation, the present research situation of Impulse echo method in China and abroad is introduced. Based on the laboratory tests, the distribution of echo signals of concrete specimens under different conditions is revealed, and the effects of grouting density, prestressed tendons, concrete thickness and concrete reinforcement on the distribution of echo signals are analyzed. The results show that for the time domain signal, the prestressed tendons and the thickness of concrete have little effect on it.) with the decrease of grouting compactness and the addition of reinforcement, the disturbance degree of time-domain signals increases 3) for frequency-domain signals, with the decrease of grouting compactness, The frequency of frequency domain signal is reduced by increasing the thickness of the main wave peak frequency. (5) when reinforced and prestressed tendons are added, the waveform signal appears clutter wave and low frequency small peak wave peak wave peak. 3. Through the ABAQUS finite element simulation in this paper, it is found that the simulation results are consistent with the experimental results. The finite element software ABAQUS is used to simulate the detection of grouting defects in concrete beam and slab by impact echo, and the defect rate of the structure can be accurately and quantitatively analyzed. Based on the finite element simulation, the state of grouting bellows with different defects is simulated, and it is found that the propagation of stress waves in finite element obeys the same rule. And with the increase of defect, only the frequency of the main peak changes gradually, and the frequency of the main peak decreases gradually with the increase of the defect. Then, the defect value and the frequency value of the main peak are quantitatively analyzed, and the function relationship between them is fitted by MATLAB software. By comparing the data of indoor test, the corresponding functional relationship between the two is deduced in the case of indoor test.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.57

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