【作者】 李星新；

【导师】 任伟新；

【作者基本信息】 中南大学 ， 桥梁与隧道工程， 2012， 博士

【摘要】 正交异性钢桥面板的疲劳开裂事例在许多国家相继报道,该问题已经成为建设与管养单位面临的一道难题。面对钢桥面板疲劳开裂问题的巨大挑战,许多学者相继展开对钢桥面板疲劳问题的研究并发表了大量文章,取得了一定成果,然而我们的研究仍然有很大的提升空间,如何对正在运营的钢桥面板疲劳寿命进行科学评估,从而及时进行检测和预防性养护,对于提高钢桥面板的耐久性并节省高额维护费用,具有重要理论意义和工程实用价值。近年来,随着桥梁健康监测技术的快速发展和应用,通过在桥梁上布设传感器,提供了大量运营过程中的有用数据。本文以我国首座千米级钢桁梁悬索桥贵州坝陵河大桥长期健康监测系统为背景,研究合理的利用桥梁健康监测系统实测数据,对正交异性钢桥面板构造细部进行疲劳寿命评估。分别基于名义应力法、热点应力法、车辆荷载谱法和基于新型桥梁疲劳寿命计的方法,对钢桥面板的疲劳寿命进行评估,最后基于疲劳时变可靠度的方法,提出钢桥面板检查策略,达到降低检测成本和提高检测效率的目的。论文主要研究内容和取得的成果包括：1.概述了正交异性钢桥面板的发展历史,对其常见开裂部位进行了总结分析；对构造细节的演变进行了详细阐述,包括纵肋型式的演变、合理刚度的演变以及连接细节的演变。对钢桥面板疲劳监测前沿技术进行了概述总结,包括动态称重(WIM)系统、光纤光栅应变监测技术以及新型的桥梁疲劳寿命计技术等。2.对桥梁健康监测系统动应力监测数据的分析处理进行了研究。对钢桥面板名义应力监测测点布设、疲劳强度的选择、应力监测数据的分析以及名义应力疲劳寿命评估等进行了系统的研究。采用名义应力法理论和监测系统实测数据,实现了坝陵河大桥正交异性钢桥面板疲劳寿命的评估。结果表明,以目前的交通荷载,坝陵河大桥桥面板疲劳寿命满足设计要求。3.对基于热点应力法监测的疲劳寿命评估技术进行了研究。分析研究了钢桥面板各疲劳细节热点应力集中系数,并对钢桥面板热点应力监测测点布设、热点应力疲劳强度的推导、热点应力监测数据的分析以及热点应力疲劳寿命评估等进行了系统的研究和总结。在此基础上建立了基于热点应力监测的疲劳寿命评估步骤,采用监测系统实测数据,实现了坝陵河大桥正交异性钢桥面板疲劳寿命的评估。结果表明,采用热点应力方法,简化了焊接形式,减少了结果的分散性,比用名义应力具有一定的优越性。4.对基于车辆荷载监测的疲劳寿命评估技术进行研究。基于动态称重系统,统计分析桥梁车辆交通流量和车重,建立车重概率模型,采用泊松过程建立车辆间距概率模型,并采用蒙特卡罗理论模拟随机车队荷载作为疲劳设计荷载。推导了适用于西部山区高速公路桥梁的标准疲劳车、随机疲劳荷载和正交异性桥面板的车轴频值谱、随机车轴频值谱。对坝陵河大桥正交异性钢桥面板常见疲劳细节进行疲劳寿命评估,所得结果与基于应力监测的结果相近,在目前交通量情况下使用寿命高于设计寿命值。5.对基于新型疲劳寿命计的疲劳寿命评估技术进行了研究。提出基于新型疲劳寿命计的剩余寿命评估方法。通过与实测推导的标准疲劳车结合,推导并建立了疲劳计电阻变化值与累积损伤度的关系式,从而可直接通过疲劳计实测的电阻变化,基于规范推导疲劳寿命。成功安装于贵州坝陵河大桥钢桥面板上的疲劳寿命计和测量数据分析结果表明,疲劳计是一种具有疲劳载荷累积记忆功能的传感元件,其不可逆的电阻变化记录监测点的交变应变历程,适用于大型桥梁等结构的长期疲劳损伤监测。6.为钢桥面板的检测养护提供依据是进行疲劳监测与寿命评估的重要目的之一,为此论文提出了钢桥面板基于疲劳时变可靠度的检测策略。推导建立了钢桥面板疲劳极限状态方程,建立疲劳时变可靠指标计算公式进而对钢桥面板疲劳时变可靠指标进行计算；建立检测策略与疲劳可靠度之间的关系,为进行科学的检测策略提供参考依据。基于疲劳时变可靠度的检测方式,跟传统的定期检测相比,具有显著的优点。更多还原

【Abstract】 Fatigue cracking problems in the orthotropic steel deck of bridges have been extensively reported in many countries, which have become a predicament during the bridge design, construction and maintenance. Facing great challenges, many scholars have carried out studies on fatigue problems of orthotropic steel deck, published numerous articles and acquired certain achievements. However, there is still a great space left for the further in-depth study. The problem of how to scientifically assess the fatigue life of a steel bridge deck in its operation stage so as to timely make corresponding inspection and preventive maintenance is of great theoretical significance in aspects of improving the durability of steel bridge deck and saving high maintenance cost, and also has practical values.In recent years, with the rapid development and wide application of the bridge health monitoring technique, vast numbers of useful data are obtained in the operating process via the sensors installed in the bridge. Based on the health monitoring system for Balinghe River Bridge in Guizhou Province, the study of how to make rational application of the measured data got from the health monitoring system to assess the fatigue life of structural details of orthotropic steel bridge deck is presented in this paper. The fatigue life evaluation of Balinghe River Bridge is intensively carried out based on the nominal stress method, hot spot stress method, the vehicle load spectrum method and the new fatigue life gauge method. At last, the time-dependent fatigue reliability method is adopted to decide on the orthotropic steel deck inspection strategy with the purpose of reducing inspection costs and enhancing inspection efficiency. The main work and obtained results are as follows:1. The history of the development of orthotropic steel deck is reviewed; the common cracking locations are summarized and analyzed. The evolution of the structural details are described in detail, including the evolution of the longitudinal rib type, a reasonable evolution of the stiffness and the evolution of the connection details. The latest techniques of orthotropic steel deck fatigue monitoring, including WIM system, FBG monitoring technique and fatigue life gauge technique are summed up.2. The analysis and process of the dynamic stress monitoring data for the bridge health monitoring system is studied. A systematic study is carried out for the layout of nominal stress monitoring testing points, the choice of the fatigue strength, the analysis of stress monitoring data and the fatigue life evaluation based on nominal stress. Based on the nominal stress method and the measured data from the monitoring system, the fatigue life evaluation of Balinghe River Bridge is realized. The results show that the fatigue life of Balinghe River Bridge meets the design requirements under the action of current traffic loads.3. Fatigue life evaluation technique based on the hot spot stress method is studied. The hot spot stress concentration factor of each and every fatigue details of steel bridge deck is analyzed. And a systematic study and summarization for the layout of the hot spot stress testing points, the derivation of the hot spot stress fatigue strength, the analysis of hot spot stress monitoring data and the fatigue life evaluation based on hot spot stress is conducted, upon which fatigue life evaluation procedures based on hot spot stress monitoring are established. By means of the measured data from the monitoring system, the fatigue life evaluation of the orthotropic steel bridge deck of Balinghe River Bridge is realized. The results indicate that the hot spot stress evaluation method simplifies the form of welding, reduces the dispersion of the results, and is superior to the nominal stress method.4. Fatigue life evaluation technique based on the vehicle load monitoring is studied. Based on WIM systems, the bridge vehicle traffic flow and vehicle weight are statistically analyzed and the vehicle weight probability model is established. The probability model of vehicle spacing is established based on Poisson process and the random team load as a fatigue design load is simulated by the Monte Carlo theory. The standard fatigue truck and the random fatigue load are selected for highway bridges in the western mountainous areas in China, the axle frequency value spectrum and random axle frequency value spectrum are derived for orthotropic bridge deck. The fatigue life of conventional fatigue details of the orthotropic steel deck of Balinghe bridge is evaluated. The results basically agree with the results based on the stress monitoring, under the current traffic condition, the actual service life is longer than the design life.5. Fatigue life evaluation technique based on the new fatigue life gauge is studied and the fatigue life evaluation method based on the new fatigue life gauge is proposed. Combined with the deduced standard fatigue truck, the relation of the change in resistance value and the cumulative damage is derived and established. And then, the fatigue life can be calculated based on the change of resistance value. The new fatigue life gauges installed in Balinghe River Bridge and the analysis of the measured data indicate that the fatigue life gauge is a sensor which has the capacity of fatigue load accumulation and memory, its irreversible resistance changes record alternating strain history of monitoring points, which is suitable for long-term fatigue damage monitoring of long-span bridges.6. One of the major purposes of fatigue monitoring and life evaluation is to provide references for the inspection and maintenance of steel bridge deck. Thereby, the inspection strategy based on fatigue dynamic reliability is proposed accordingly. The fatigue limit state equation is established, meanwhile, the formula of fatigue dynamic reliable indicator is proposed to calculate the time-dependent reliability index of steel bridge deck. The relation between the inspection strategy and fatigue reliability is built, so as to provide references for making scientific inspection strategy. Compared with the traditional regular inspections, the inspection method based on fatigue reliability has significant advantages.更多还原