混凝土结构耐久性的模糊综合评判及可靠度评价

发布时间：2018-04-16 11:05

本文选题：耐久性 + 模糊数学　；参考：《兰州理工大学》2013年硕士论文

【摘要】：混凝土结构已经代替砖混结构,成为现代建筑结构的主要形式。近年来,建于早期的许多建筑物在使用期限内发生严重破坏,危及人民生命财产安全,这些破坏大多是由于钢筋混凝土耐久性不足引起的。在未来一段时间内,我国将会有大量的混凝土结构构件进入老化期。耐久性失效已经构成了“全球性的混凝土耐久性危机”,进行混凝土结构耐久性及其加固修复技术研究,对延长结构使用寿命,防止重大事故发生,提高综合经济效益等方面将具有重大意义。本文在回顾以往对钢筋混凝土结构耐久性问题的研究成果的基础上,对影响钢筋混凝土结构耐久性的因素做了进一步研究,其主要内容如下： 1、系统的总结了影响混凝土耐久性的因素,并用层次分析法对其进行分层,用模糊层次分析法对某钢筋混凝土梁进行耐久性评价,评价结果与实际情况相符合,说明模糊综合评价方法可操作性强、效果较好,可在混凝土耐久性评价方面广泛应用。 2、介绍了可靠度鉴定的有限元概率设计(PDS),以及可靠度理论在混凝土耐久性方面的应用。 3、用大型有限元分析软件ANSYS模拟分离式钢筋混凝土梁,对裂缝宽度、深度、数量不同的梁进行模拟分析,总结裂缝对钢筋混凝土结构耐久性的影响,并对其进行可靠度评价。最后得出结论： 1、基于层次分析法的模糊综合评价在混凝土耐久性评价中取得了较好的效果,模型的建立符合实际情形。模糊综合评价方法可操作性强、效果较好,可以很好地用在于混凝土结构构件的耐久性分析当中,概率分析法已经逐渐取代传统经验法和实用鉴定法,将成为未来可靠性鉴定的主要方法。 2、可以用大型有限元分析软件ANSYS,模拟裂缝条件下混凝土梁的的受力情况,确定裂缝对耐久性的影响程度,并确定不同裂缝条件下混凝土梁的可靠度。结果表明,裂缝对混凝土结构构件的耐久性有不利的影响,耐久性随着裂缝宽度、深度及数量的增加而降低。对影响混凝土耐久性的其他因素,也可以用ANSYS软件来进行尝试模拟。 3、裂缝对应力及位移计算结果影响的效果不是十分显著,这是因为裂缝对耐久性的影响并不是直接作用于梁上,而是主要是通过影响钢筋锈蚀,降低钢筋抗拉强度来降低钢筋混凝土梁的耐久性。
[Abstract]:Concrete structure has replaced brick-concrete structure and become the main form of modern building structure.In recent years, many buildings built in the early period of life have been seriously damaged, endangering the safety of people's lives and property, most of which are caused by the lack of durability of reinforced concrete.In the future, a large number of concrete structural members in China will enter the aging period.The durability failure has already constituted "the global concrete durability crisis", carries on the concrete structure durability and the reinforcement and repair technology research, to prolong the structure service life, prevents the serious accident occurrence,It will be of great significance to improve the comprehensive economic benefits.On the basis of reviewing the previous researches on the durability of reinforced concrete structures, this paper makes a further study on the factors affecting the durability of reinforced concrete structures, the main contents of which are as follows:1. The factors that affect the durability of concrete are summarized systematically, and it is stratified by analytic hierarchy process (AHP), and the durability of a reinforced concrete beam is evaluated by fuzzy analytic hierarchy process (FAHP). The evaluation results are in accordance with the actual situation.It shows that fuzzy comprehensive evaluation method is feasible and effective, and can be widely used in concrete durability evaluation.2. The finite element probability design of reliability evaluation and the application of reliability theory in concrete durability are introduced.3. The split reinforced concrete beam is simulated by ANSYS, the crack width, depth and number of beams are simulated and analyzed, and the influence of cracks on the durability of reinforced concrete structure is summarized, and the reliability of the beam is evaluated.Finally, it is concluded that:1. The fuzzy comprehensive evaluation based on analytic hierarchy process (AHP) has achieved good results in concrete durability evaluation, and the establishment of the model is in line with the actual situation.The fuzzy comprehensive evaluation method has strong maneuverability and good effect. It can be well used in the durability analysis of concrete structural members. The probabilistic analysis method has gradually replaced the traditional empirical method and practical appraisal method.It will become the main method of reliability evaluation in the future.2. The finite element analysis software ANSYScan be used to simulate the stress of concrete beam under crack condition, determine the influence degree of crack on durability, and determine the reliability of concrete beam under different crack condition.The results show that cracks have an adverse effect on the durability of concrete structural members, and the durability decreases with the increase of crack width, depth and quantity.Other factors affecting the durability of concrete can also be simulated by ANSYS software.3. The effect of crack on stress and displacement calculation is not very significant, because the effect of crack on durability is not direct effect on beam, but mainly through influence on corrosion of steel bar.Reduce the tensile strength of steel bars to reduce the durability of reinforced concrete beams.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375

【参考文献】