【作者】 李晓林；

【导师】 刘扬；

【作者基本信息】 长沙理工大学 ， 土木工程， 2015， 硕士

【摘要】 钢-混组合桥面系作为一种新类型结构已经在大跨度悬索桥中广泛应用,并且取得了良好的经济效益。随着运营时间、车流量和载重量的增加,服役期内桥梁的寿命急剧减少,钢-混组合桥面系在车辆荷载反复作用下的疲劳问题日益突出。目前,我国关于钢-混组合桥面系的研究重点是静力方面,而关于疲劳性能方面的科研深度较浅,因此研究钢-混组合桥面系在车辆荷载反复作用条件下的疲劳性能意义重大。本文根据公路桥的实测交通调查数据,并结合有限元理论建模分析,进行钢-混组合桥面系的疲劳性能研究。具体研究内容有:(1)参考国内外相关文献,对钢-混组合结构疲劳的基本理论和计算方法进行了详细的介绍。通过比较各种方法的优劣和实际情况,选择Miner准则的S-N曲线分析方法来进行钢-混组合桥面系的疲劳损伤计算和寿命评估。(2)对江苏某公路大桥24h实测交通数据进行计算分析,将货车归纳分成常见的16类车型,采用疲劳等效损伤原理和英国BS5400有关规范将16类车型总结为7类典型车,从而得到了该桥的模型车辆荷载谱;(3)以实际工程为背景建立了钢-混组合桥面系节段模型,基于有限元理论方法来研究其疲劳性能。在钢-混组合桥面系节段模型中分别加载7类典型车,利用ANSYS的瞬态动力分析功能得到钢-混组合桥面系(钢纵梁和桥面板)上关注点(受力最不利点)的应力-时程数据,进而计算其疲劳损伤和疲劳寿命。计算发现关注点(1)(受力最不利点)疲劳寿命比设计寿命(100年)低,表明车辆动荷载对钢-混组合桥面系的疲劳性能影响显著,所建立的模型车辆荷载谱由于来自实际交通调查,驶过该公路大桥的货车可能存在超载现象。(4)分析计算了在BS5400标准疲劳车和AASHTO规定疲劳车作用下,钢-混组合桥面系模型中各关注点的疲劳损伤量。研究表明:钢-混组合桥面系模型中受力最不利点受的疲劳损伤远大于其他位置处,车辆的参数值(总重、轴重和轴距)的差异可能会造成疲劳损伤量的不同,进而导致钢-混组合桥面系结构疲劳寿命的差异。更多还原

【Abstract】 Steel-concrete composite bridge deck which is a new type of structure has been used in large span suspension bridge and has achieved good economic benefits. The economy has got good result after using the new deck. With the increase in working time, traffic and vehicle loadings, the life of the bridge under service time has been reduced drastically. The fatigue problem of steel-concrete composite bridge deck under vehicle loadings is increasingly outstanding. At present, the research of steel-concrete composite bridge deck is focused on the static aspects, and there is less research of fatigue aspects in China. So it is significant that we research the fatigue performance of steel-concrete composite bridge deck under vehicle loadings. In this paper, we combine the actual traffic survey data of the highway-bridge and finite element analysis method to research the fatigue performance of steel-concrete composite bridge deck under vehicle loadings. Detailed research contents are as follows:(1) After reading Chinese and foreign related literature, this paper has carried on the detailed introduction which is about the basic theory and calculation method of steel-concrete composite structural fatigue. By comparing the merits of various methods and the actual situation, we choose the S-N curve of Miner standards to analyze the fatigue damage and life.(2)Through the calculation and analysis of the 24 hours’ traffic data of a highway bridge in Jiangsu province, trucks were grouped into 16 categories of common models. By using fatigue damage equivalence principle and the British BS5400 relevant norms, the 16 categories are divided into seven categories of models typical car. Then, we can establish a model vehicle load spectrum frequency value.(3)The steel-concrete composite bridge deck segmental model is established by the background of actual project, based on the theory of finite element method to study the fatigue properties. The seven categories of typical vehicles are loaded into the finite element model. The stress-time history data of steel-concrete composite bridge deck was obtained by using the transient dynamic analysis function of ANSYS. Then, People can calculate the fatigue damage and predict fatigue life of structure. It is found that the fatigue life of concerns(1)(point of forcing most negative) is lower than the design life(100 years). It shows that vehicle dynamic load significantly affect the fatigue properties of steel-concrete composite bridge deck. The vehicles of passing the bridge may overload, because the load spectrum of model vehicle were built from the actual traffic investigation.(4) Each concerns in steel-concrete composite bridge deck model, which is in the action of BS5400 and AASHTO standards fatigue car, is solved and analyzed the fatigue damage.Studies show that the fatigue damage of the point of forcing most negative in the steel-concrete composite bridge deck model is much larger than other locations. The differences of vehicle parameter value, such as total weight, axial spacing and single axle loadings, may cause the different amount of fatigue damage, leading to fatigue life of steel-concrete composite bridge deck differences.更多还原