【作者】 赵卫国；

【导师】 杨炳成；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2007， 博士

【摘要】 公路交通是国民经济的命脉,桥梁是公路的咽喉,桥梁的良好使用状况是公路交通安全的重要决定因素,是保障公路畅通的必要条件。随着公路交通流量增长,桥梁承受着越来越重的负荷。公路桥梁的病害与损伤、承载能力降低、使用性能下降是一个日益严重的问题,桥梁的病害与构件损伤是普遍现象。在各类桥型中,以梁式桥居多。上部结构钢筋混凝土梁的病害对结构使用性能的下降占主导因素。对于存在先天质量缺陷或损伤的梁桥的上部结构,各种损伤、病害对构件承载能力的影响如何考虑,对于其承载能力和安全度如何分析与计算,目前尚没有统一的标准和方法,只能根据破坏程度按个人的经验进行折减和粗略估算,计算精度相当差。为了准确评估病害对梁桥使用性能和承载能力的影响,指导加固设计和桥梁维护管理,本文依托于河北省交通厅《混凝土梁损伤及承载性能研究》的科研项目(课题编号Y-030201)对公路受损钢筋混凝土梁的病害进行了分析,损伤后的承载能力进行了研究。第一步病害分析中先结合桥梁技术状况调查对钢筋混凝土梁的损伤情况及其影响进行深入的调研和分析研究。归纳整理出了公路梁式桥上部结构的典型病害特征。然后对各类型的典型病害的成因、作用机理和对结构物的承载能力、耐久性等使用性能的影响以及各种病害间的交互作用与影响进行了深入的分析和讨论。在损伤后承载能力分析方面,以前文献的钢筋混凝土梁承载能力研究中,以无破损理想状态钢筋混凝土梁受力全过程分析居多,对于病害因素的考虑较少。一些文献即便进行了研究,也只涉及一两种病害影响的分析。但由于公路桥梁使用状态的复杂性和工作环境的多样性,往往在一座桥上,甚至一片梁上常常同时存在多种典型病害,这些病害都能够对承载能力造成较为严重的影响。论文结合实际情况,考虑钢筋混凝土梁各种常见典型病害,建立了全面的受损钢筋混凝土梁有限元分析模型。选择了适合于钢筋混凝土梁承载能力分析的有限元模型和钢筋、混凝土、粘结力、裂缝以及各种典型病害损伤的有限元单元和有限元模拟方法,能够对绝大多数公路钢筋混凝土梁桥病害的影响进行分析,并实现了受力过程的微观、全程分析。在研究过程中,主要进行了如下的创新性工作:一、提出了基于受力特性的混凝土破损病害分类,提出了标准的受力分析方法,分别构造了各类型破损病害的有限元单元模型。二、提出了基于病害调查和力学分析的公路钢筋混凝土梁损伤后承载性能评价方法以及相关指标——损伤承载力和承载力损伤系数。三、对混凝土腐蚀病害程度进行分级,并提出了各级腐蚀病害的有限元模拟方法,还提出了腐蚀膨胀力荷载效应的有限元分析简易算法。四、对钢筋锈蚀病害发展程度进行了分级,并提出了各级锈蚀病害的有限元模拟方法。更多还原

【Abstract】 The highway communication is the lifeblood of the national economy, and the bridge is a throat of the highway, so the good use status of the bridge is the important decisive factor of the traffic safety and the requirement of ensuring unblocked of the highway. As the flow of highway communication increases, bridges are bearing heavier and heavier load. Disease, damage, bearing capacity reduction of the highway bridge and the drops of serviceability are serious problems day by day. It is a general phenomenon that diseases exist in the bridges and components of the bridges are damaged. In all kinds of bridge types, Beam Bridge takes the majority. The disease of superstructure of reinforced concrete beam takes the leading factor to the decline of structural serviceability. As to superstructures of Beam Bridge which have congenital quality defect or damage, how to consider various damage impact on bearing capacity of component, how to analyze and calculate bearing capacity and degree of safety, there are no unified standard and method yet at present. Can only follow the damage degree and personal experience to reduce and estimate roughly at present, so the precision of calculation is quite bad.In order to assess the impact of the diseases on the serviceability and bearing capacity of beam bridges accurately and to guide the design of strengthening and maintenance management of bridges, the diseases of damaged concrete beams in the highway are analyzed and the bearing capacity after damaging is researched based on the scientific research project "the concrete beam damages and bearing capacity research" (subject serial number Y-030201) of the traffic office of Hebei. First step, combining the technological investigate of the bridge, the damage situation of reinforced concrete beams and their influence are analyzed and researched thoroughly. The typical disease characteristic of super structure of beam bridges of the highway is sum up. Then the cause of the typical disease, mechanism of function, the impact on serviceability such as the bearing capacity and durability and the influence among various diseases are analyzed and discussed thoroughly.As to the analysis of bearing capacity after damaging, non-destructive ideal state concrete beam that is analyzed in the whole course by strength is in the majority and there is less consideration of the disease factor in the former literature. Even some research is carried on in literature, but it only involves the analysis of a few kinds of disease influence. Because of the complexity of the bridge performance of the highway and the variety of the working environment, often on a bridge, even on a slice of beam, there are many kinds of typical diseases at the same time. The disease can cause comparatively serious influence on the bearing capacity. Based on the actual conditions, various common typical diseases of reinforced concrete beam are considered and the overall damaged reinforced concrete beam finite element models are set up. The suitable finite element model for analyzing reinforced concrete beam bearing capacity, the finite element unit and finite element simulation method about reinforcing bar, concrete, bonding strength, crack and various typical disease damage are chose, which can analyze the impact on disease of reinforced concrete beam of most highway bridges and realize micro and whole course analysis of the stress.In the course of the study, the following innovative work is carried on:First, the disease classification of damaged concrete according to the stress characteristic is proposed and the standard receiving the analytical method of strength is put forward. The finite element model of the structure according to all kinds of damage is differentiated.Second, according to disease investigation and mechanics analysis, the bearing capacity appraisal method and relevant indexes of highway reinforced concrete beam after damaged—damage bearing capacity and bearing capacity damage coefficient are proposed.Third, the corrosion disease intensity of concrete is graded and the finite element simulation method of the corrosion disease at all levels and the finite element simple analysis method and easy algorithm of corrode swelling pressure load effect are put forward.Fourth, the corrosion disease development degree of reinforcing bar is graded and the finite element simulation method of the corrosion disease at all levels is proposed.更多还原