【作者】 孙晓燕；

【导师】 黄承逵；

【作者基本信息】 大连理工大学 ， 结构工程， 2004， 博士

【摘要】 20世纪50年代以来，我国修建了一大批混凝土桥梁，随着使用时间的推移，交通量的增长和车辆荷载的提高，既有桥梁安全评估和使用寿命问题提到了重要的议事日程上来。由于存在问题的既有桥梁数量众多，分析既有桥梁的剩余承载力和对后续服役期内的使用性能对合理利用既有桥梁，精确评估既有桥梁剩余寿命和维修加固决策有重要的经济意义和研究价值。加固、维修既有桥梁，不仅提高现有桥梁通行能力，缓解日趋紧张的交通压力，而且可以节省资金，使桥梁建设可持续发展，因此，既有桥梁的维修加固具有深刻的理论背景和广阔的应用前景。采用FRP加固既有桥梁作为新材料新工艺正在国内公路桥梁系统普及，有效的提高了既有桥梁的承载力和剩余使用寿命。本文结合辽宁交通科技重点项目(0101)：在役桥梁耐久性评估，主要开展以下研究工作： 1．进行了12根钢筋混凝土适筋梁的超载试验，主要针对不同的预加荷载幅值和不同超载次数对不同配筋率的钢筋混凝土桥梁构件受弯性能的影响进行研究，分析超载对钢筋混凝土梁桥使用性能的影响规律。 2．进行了12根玻璃纤维布加固超载后钢筋混凝土梁的试验，并分析比较了不同超载幅值的钢筋混凝土梁超载后加固效果。试验部分主要针对不同的预加荷载幅值对不同配筋率的钢筋混凝土梁桥的加固后受弯承载力的影响进行研究。 3．在19根钢筋混凝土梁的抗剪试验的基础上，分析循环加载损伤对斜裂缝宽度和斜截面承载力的影响，为损伤后的钢筋混凝土梁斜截面承载力的评估提供依据。 4．通过对钢筋混凝土简支梁进行反复超载试验，测出构件从完整到破损，以及不同超载幅值和次数对应损伤状态下的频率和阻尼比等模态参数，考查了其与构件承载力的关系，分析了频率和阻尼比随损伤状态不同的变化规律，根据试验结果得到频率和荷载等级关系的经验公式，为采用动态法评估既有桥梁提供了理论依据。 5．分析了既有钢筋混凝土桥梁正常使用极限状态可靠度分析的特点；以最大裂缝宽度作为构件正常使用状态的分析对象，研究和讨论了模糊失效界限和荷载等级提高对既有桥梁正常使用极限状态可靠度影响；建立了混凝土构件在正常使用状态下的极限状态方程，并根据实际桥梁的检测资料进行了可靠度计算，讨论了正常使用情况下各个因素对混凝土构件可靠指标的影响。 6．由于设计荷载标准的提高和经济发展的需要，既有桥梁常常需要承担超过其设计标准的汽车荷载，称其为超载。结合本课题的超载试验，考虑超载对裂缝宽度的影响，采用模糊随机可靠度分析方法，对既有桥梁进行正常使用极限状态可靠指标验算，并与未考虑超载影响的可靠指标进行了比较。 7．通过对国内外大量纤维布加固试验资料进行分析计算，得到了钢筋混凝土矩形构件受弯加固和受剪加固的计算模式不定性系数的统计参数，为加固后既有桥梁可靠度分析提供了计算依据。针对既有钢筋混凝土结构构件，考虑不同维修加固加固摘要方式，分析了外贴纤维布加固后桥梁的时变可靠性。 8.利用实际检测数据修正抗力模型，对既有钢筋混凝土梁桥时变可靠度进行了计算，同时比较分析了汽车荷载等级的提高和采用不同维护加固措施对后续服役期内时变可靠度的影响。基于既有桥梁的时变可靠度，以后续服役期内收益期望值最大为目标函数，对既有桥梁的维修加固决策进行了探讨。更多还原

【Abstract】 Bridges are designed to function over long periods of time. The incidence of structural deterioration increases with bridge age due to corrosion, fatigue and other forms of material property deterioration. During this same period vehicle, loads and legal load limits have been steadily increasing. So exisiting bridges experience changes in both resistance and applied loads which are time variant. Structural elements composed of concrete and reinforcing steel are frequently determined inadequate to sustain current or new load levels imposed on bridges. There is an increasing need, and a great challenge to repair and update the transportation infrastructure of the world. Recently, a new method of retrofit has been studied that uses the addition of externally bonded fiber reinforced polymers (FRPs) to increase load capacity. Therefore, based on the Liaoning Provice Communication Department Key Science Foundation Project (No.0101), this thesis will focus on the following aspects:1. Based on the experimental investigation of 12 reinforced concrete beams, the influence of truck overloads on highway bridge members flexural performance is evaluated. With the value and the times of overload and the percentage of reinforcement as the main parameters, the damnification caused by overloads are studied.2. The performance of 12 beams with external flexure reinforcement was compared to the result of 12 beams with no external reinforcement. The influence of truck overloads on highway bridge members flexural performance is evaluated. With the value and the times of overload and the percentage of reinforcement as the main parameter, the damnification caused by overloads are studied.3. The damnification of diagonal section caused by cycle loading is analysed based on the experiment of 19 reinforced concrete beams. The main varied parameters are reinforcement ratio, shear span and times of cycle loading. With the number of cycle loading increased, the shear capability of reinforced concrete beams are decreased, while the crack width is increased dramatically. The analytical and experimental results can be used for qualitative evaluation of reinforced concrete beam shear capability after damnification.4. Based on the dynamic loading experiment of simply supported beam, the influence of overload on reinforced concrete beams is investigated. The changed parameters are over load value and number. Modal parameters such as frequency, damping ratio are identified from initial state to damaged state. The change law of above modal parameters is obtained. The regress expressions of frequency is given based on the test result. The analytical and experimental results can be used for quantitative dynamic evaluation of reinforced concrete beam after damnification.5. Characteristics of reliability analysis on serviceability limited state for existing reinforced concrete bridges are discussed. The effect of improvement of live load and difference of fuzzy failure bounds on reliability is studied. With crack width as the analysis parameter of normal limited state, The calculation on a reinforced concrete bridge is illustrated herein based on updated inspection information.6. The bridges are structurally deficient particularly for projected increase of trafficloads, which can be called overload. The effect of improvement of live load and difference of fuzzy failure bounds on reliability is studied. With crack width as the analysis parameter of normal limited state, the reliability analysis on serviceability limited state for existing reinforced concrete bridges is analyzed and the result is used to compare with which not considering the influence of overload.7. The statistical parameter of flexural calculate mode on RC beam strengthened with FRP is given after analyzing the lots of experiment results.The influence mechanism of bridge resistance after reinforcement is discussed. According to durability research and corresponding experimentation, the aging of FRP material and interface of FRP and concrete can be ignored. Therefore, the更多还原