RC桥梁寿命的可靠度分析方法研究

【作者】 张彦飞；

【导师】 邬晓光；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 我国在工程结构可靠度方面的研究已经取得了巨大的成就,但近年来由于上世纪80年代以前修建的RC桥梁有不少因没有提前做出合理的寿命评估而出现坍塌事故。本文主要以可靠度理论为基础提出一种对旧桥进行可靠性评估并分析旧桥使用寿命、剩余使用寿命的方法,为即将超过使用寿命期的桥梁提供加固改造依据,以进一步减少事故率。 本文主要在借鉴机械结构可靠度分析中结构寿命分析方法的基础上,提出了桥梁结构的可靠度寿命分析方法,该方法以可靠度计算方法的蒙特卡罗法与响应面法为基础,同时建立了桥梁结构的抗力与荷载模型,在ANSYS程序的可靠度模块中建立以时间为基本变量的材料性能参数变量、荷载变化特征变量,并指定各输入变量服从的分布形态,通过计算得出桥梁结构的应力、变形,再由两条桥梁可靠性判定准则得出桥梁在运营不同时间的可靠概率,由此可绘出桥梁的时间—可靠概率关系曲线,从而可以从图形中直接得出不同使用期的可靠概率。本文以RC简支梁为算例进行了计算,该算法对其他类型的RC桥均适用,只是在建模过程需要考虑更多的材料间共同工作的时间变量。更多还原

【Abstract】 We have gained great achievement in the study of confidence level of engineering structure. However many RC bridges which were built before 1980 appear slump, because these bridges are not appraised reasonably in advanced. In the basis of confidence level’s theory this paper puts forward a kind of analysis method of old bridges’ reliability appraisement, service life and surplus service life. This will supply law of reinforcement and reformation for the old bridges near service life, and further makes the accident occurrence to lowest probability.This paper bases in the analysis of mechanical structure’s reliability service life, and presents analysis method of confidence level of bridge structure’s service life. The analysis uses the Monte-Caro and Response Surface method, builds the resistance model and load model of bridge structure, and in the ANSYS program’s reliability module sets the variables of the based time’s material nature and load character, at the same time appoints the distribute shape of every variable. By the program’s calculation we can get the bridge’s stress and deforming, leaning against two reliability determination criterions obtain the different confidence level in different time, draw the bridge’s time-confidence level curve, and directly read the different time’s confidence level from the curve. This paper only calculates the freely supported RC beam, in fact the method is fit for every RC bridge, but we must consider more time variables of all materials’ common work in the course of building model.更多还原