【作者】 李治国；

【导师】 张彬；

【作者基本信息】 辽宁工程技术大学 ， 岩土工程， 2008， 硕士

【摘要】 桥梁在使用过程中会受到各种外界因素的作用,致使结构承载力可靠度水平随着时间的推移逐渐降低,最终不能满足预定设计功能要求。因此,许多服役桥梁都需要进行评估鉴定,进而为公路桥梁管养单位提供可行的抉择依据,以采取合理的措施进行加固。本论文在借鉴前人研究成果的基础上,对桥梁承载力的可靠度评估方法做了一些探讨和研究,主要研究内容及结论如下:简要介绍了结构可靠度理论及各种计算方法,分析结构抗力衰减的理论模型和简化计算方法;建立了服役RC桥梁考虑荷载和抗力时变效应的承载力可靠度评估模型,同时,提出承载力可靠度评估的计算步骤,实现了桥梁承载力动态可靠度指标的计算。借鉴建筑结构中安全度等级评定规范,展开服役RC桥梁承载力评定标准的研究,提出了一种服役桥梁承载力可靠度评定等级标准,为桥梁可靠性等级评估打下良好基础。以喇嘛湾黄河公路大桥为工程算例,采用桥梁承载力可靠度评估模型,建立主梁正截面抗弯承载能力动态可靠度极限状态方程,进行主梁抗弯承载力动态可靠度的计算,参考本文建立的评估等级标准对其承载力进行等级划分。算例分析表明本文建立的承载力评估模型在实际工程中的应用是可行的。利用ADINA有限元软件,建立喇嘛湾黄河公路大桥上部主梁结构在试验荷载作用下三维实体非线性有限元模型,进行全桥受力仿真分析。计算求得桥梁在不同工况作用下的挠度、应力、应变和自振频率等,通过模拟值与实际检测值的比较,得出桥梁结构的实际承载力,这也反过来验证了桥梁承载力可靠度评估模型及其评估结果的正确性与实用性,为其他类似工程提出可以借鉴的结论。更多还原

【Abstract】 The bridge receives various factors’ function in the process of use, its bearing capacity can reduce to safety level and operation condition cannot satisfy the request. Hence, many service bridges need to carry on the appraisal, then provides the feasible choice for the highway bridge maintain department, takes the reasonable measure to carry on the reinforcement. This article, basing on extractting the predecessor research results, has initially made some research work of Margin of safety appraisal method of bridge supporting capacity and the finite element analysis. The main research contents and conclusions are as follows:This paper has introduce content of structure reliability theory and computation method, analyzed the attenuation theoretical model of Resisting force which takes the structure resisting force weakening into account, and introduced a kind of simplification computational method. It has discussed compute model of in-service structure bearing capacity reliability which calculated dynamic change of load and resisting force. This paper profited from the structure reliability criterion, and developed research of RC bridge bearing capacity appraisal standard, and proposed one kind of service bridge supporting capacity margin of safety evaluation rank standard, has built a good foundation for the bridge reliability evaluation.Taking the Lamawan Yellow River Bridge as example, using the above mentioned margin of safety appraisal model, this paper established reliability limiting condition equation which calculates dynamic change of load history and the resisting force along with the time, and finally realizes reliability computation. The appraisal rank division has been used into this bridge. By analysis, it thought that this method which is based on the reliability theory is feasible in the actual project.By using the ADINA software, it has established 3D finity model under the action of load and has carried through simulation analysis, and lastly obtained bridge response of the stress-strain and frequency and so on. By comparing the simulate value with the examination, it correctly appraised bridge actual bearing capacity, and then validates accuracy of the model this article proposed. Eventually, proposed many useful conclusions which can use to other similar project.更多还原