【作者】 黄杰；

【导师】 吴瑾； 程吉昕；

【作者基本信息】 南京航空航天大学 ， 结构工程， 2006， 硕士

【摘要】 鉴于实际工程中大量存在腐蚀钢筋混凝土结构承受反复荷载作用,但其力学性能研究不多的问题,本论文进行了锈蚀钢筋混凝土梁抗弯疲劳试验,研究了应力比和钢筋锈蚀率对锈蚀钢筋混凝土梁抗弯疲劳性能的影响,得出了锈蚀钢筋的应变与构件疲劳寿命之间的关系曲线,主要研究内容及结论如下:(1)在循环荷载下,混凝土残余变形基本符合三阶段变形规律,力学性能劣化,疲劳损伤积累。纵筋残余应变增加,增加幅度减小,锈蚀钢筋力学性能劣化,疲劳损伤积累。(2)应力比对跨中挠度的影响呈线形关系,且应力比较大时,跨中挠度随循环次数的增长相对较小;应力比较小时,跨中挠度随循环次数的增长相对较大。应力比对试件梁的最大裂缝宽度影响显著,应力比越大,疲劳寿命越长,直接影响试件梁在疲劳荷载作用下的性能。(3)轻微锈蚀试件梁的跨中挠度在静载和循环荷载下比未锈蚀梁小;轻微锈蚀试件梁的最大裂缝宽度比未锈蚀试件梁的最大裂缝宽度大;轻微锈蚀试件梁的疲劳寿命比未锈蚀试件梁的疲劳寿命降低,钢筋锈蚀是疲劳寿命的敏感因素。(4)钢筋应变ε与试件梁的循环次数N之间有规律性,应变ε越大,疲劳寿命越短,两者成反比关系。更多还原

【Abstract】 Base on the problem of large quantity fatigue loads on corroded R.C. structure and small quantity study of its mechanical property, bending resistance fatigue test of corroded R.C. beams is discussed in this paper. The influence of stress ratio and re-bar weight loss ratio on bending resistance fatigue performance of corroded R.C. beams are researched, and the relation between strains of corroded re-bars and fatigue life of beams are obtained. The main research contents and conclusions are as following:1. Under the fatigue loads, the overstrain of concrete approximately coincidences three stages strain development and accumulation rule, and the mechanical property of concrete is deteriorated. The fatigue damage of concrete is accumulated. The overstrain of re-bars increases and the increase rate decreases. The mechanical property of corroded re-bars is deteriorated, and the fatigue damage of re-bars is accumulated.2. The relation between stress ratio and span centre deflection is linear, and when the stress ratio is large, the increase of mid-span deflection by cycle index is small. The smaller the stress ratio is, the larger the increase of span centre deflection by cycle index is. The influence of stress ratio on maximum crack width of specimens is obvious, and the larger the stress ratio is, the longer the fatigue life is, it can influence the mechanical property of specimens directly.3. The mid-span deflection of slight corrosion specimens is smaller than that of non-corrosion specimens on the static loads and the fatigue loads; the maximum crack width of slight corrosion specimens is larger than that of non-corrosion specimens; fatigue life of slight corrosion specimens is shorter than that of non-corrosion specimens; the corrosion of re-bars is a sensitive factor to fatigue life.4. The relation between re-bars strainsεand cycle index N is obvious. The larger theεis, the shorter the N is, and the relation of them is inverse ratio.更多还原