考虑车桥耦合的拱桥吊杆体系安全及耐久性研究

发布时间：2018-04-08 07:14

本文选题：车桥耦合　切入点：吊杆体系　出处：《大连海事大学》2017年博士论文

【摘要】：拱桥结构在当代桥梁建设中得到越来越多的应用,这一桥型的安全性和耐久性问题也日益突出,其中,在中下承式拱桥中以吊杆体系的问题最为显著。近年来发生的多起拱桥坍塌事故,大多是由于吊杆体系发生破坏所导致。研究发现,在大量的吊杆体系破坏实例中,常常是以短吊杆失效为主,或短吊杆首先发生失效。影响吊杆体系耐久性的原因是多方面的,如腐蚀、疲劳等因素。一般地,可以认为同一拱桥上各吊杆所处的自然环境是相同的,长短吊杆之间这种耐久性上的差异,主要是由于车辆荷载产生的动力效应不同而导致。因此,有必要通过详尽的分析,研究拱桥吊杆体系的安全及耐久性问题。本文在考虑车桥动力耦合的基础上,分析了吊杆体系尤其是短吊杆易于破坏的机理,深入研究了提高吊杆体系耐久性及保障吊杆体系安全性的设计方法。主要内容如下:首先,建立车桥耦合动力分析模型。分别建立了大跨度拱桥三维有限元结构模型、空间多轴车辆模型和路面不平度模型并由三个模型组成车桥耦合动力分析模型,进行车桥耦合分析。通过桥梁静动态响应的计算结果与桥梁荷载试验实测结果的比较,验证了所建立的拱桥动力分析模型,保证了模型的可行性。其次,基于所建立的考虑车桥耦合的动力分析模型,对吊杆体系的动力响应进行分析。通过对吊杆应力冲击效应、弯曲效应的计算分析,研究了不同车速、车重、路面不平度以及车辆加速度对吊杆动力响应的影响。研究表明,车辆荷载对吊杆体系产生显著的冲击效应和弯曲效应,进而在吊杆截面产生较大的应力变幅和明显的不均匀应力分布,使吊杆体系易于疲劳破坏。短吊杆截面应力水平高于长吊杆,受冲击作用更为显著,因而更易疲劳破坏。然后,基于本文所揭示的短吊杆更易疲劳破坏的工作机理,提出了吊杆体系的等刚度模型来提高吊杆体系的耐久性。通过调整吊杆体系轴向刚度来改善短吊杆在车辆荷载作用下的受力条件,提高短吊杆的抗冲击性能,延长短吊杆使用寿命,进而提高整个吊杆体系的耐久性。同时,基于实际监测车流统计模型所建立的车速车重联合分布模型,建立车流荷载并通过车流加载分析,对等刚度模型中吊杆体系的耐久性进行了评估。最后,针对吊杆体系失效难以预测的问题,通过增设预警吊杆,提出了具有预警与破损安全功能的新型双吊杆体系模型。基于该模型,探讨了面向疲劳寿命的体系设计方法。通过使用寿命设计使吊杆体系具备以下性能:(1)预警吊杆与工作吊杆具有经济合理的疲劳寿命差;(2)预警吊杆破损时,保证工作吊杆的安全和整体结构形态正常。从而提高了吊杆体系安全运营的可靠性。通过调整预警吊杆初始应力来实现与工作吊杆之间的疲劳寿命差异。通过车流加载进行疲劳寿命分析,对预警功能进行了评价。在此基础上研究了吊杆体系损伤程度对疲劳寿命差异的影响,进一步评价了该吊杆体系模型的预警与破损安全性能。
[Abstract]:The arch structure is used more and more widely in the modern bridge construction, the bridge safety and durability problems have become increasingly prominent, which, in the lower arch bridge in the boom system problems are most significant. Many bridge collapse in recent years, mostly caused by the failure in the boom system study found that, in a large number of suspender system failure examples, often with short suspender failure, or failure reasons. First, short suspenders suspender system durability influence is in many aspects, such as corrosion, fatigue and other factors. In general, can be considered at the same arch bridge suspender's natural environment is the same, the durability of the difference between the length of the boom, is mainly due to the different dynamic effect of vehicle load have caused. Therefore, it is necessary through the detailed analysis of the security and durability of the arch bridge suspender system The problem. Considering the dynamic coupling on the analysis of the mechanism of short suspenders suspender system especially easy to destroy, in-depth study to improve the design method of suspender system durability and security suspender system security. The main contents are as follows: firstly, build a vehicle bridge coupling dynamic analysis model. The three-dimensional finite long span arch bridge element structure models are established, the multi axis vehicle space model and road roughness model and consist of three models of vehicle bridge coupling dynamic analysis model, coupled analysis. Through comparison of test results and the dynamic response of the bridge of Liang Jing bridge load test results, verify the dynamic analysis model of arch bridge is established, the model of the feasibility. Secondly, considering the dynamic analysis model of vehicle bridge coupling based on the dynamic response of the system, on the analysis of the impact stress of derrick Effect analysis and calculation of the bending effect of different speed, weight, and influence of road roughness and vehicle acceleration on the dynamic response of the boom. The study shows that the impact of vehicle load effect and the bending effect of suspender system, resulting in high stress amplitude and obviously uneven stress distribution in the cross section. The crane system is easy to fatigue damage. The short section of the stress level is higher than the long boom boom, the impact is more significant, so it is more easy to fatigue failure. Then, the working mechanism of short suspenders disclosed more easily fatigue failure based on the proposed boom system such as the stiffness model to improve the durability of the boom system. By adjusting the axial stiffness of the suspender system to improve the short suspenders under vehicle load stress condition, improve the anti shock performance of short suspenders, prolong the service life of short suspenders, and improve the whole The durability of the suspender system. At the same time, based on the actual monitoring of traffic statistics model of speed weight joint distribution model, the establishment of traffic load and traffic load through the analysis, the durability of the equivalence rigidity model of suspender system is evaluated. Finally, aiming at the failure of the suspender system is difficult to predict, by adding a warning boom, put forward a new type of double suspender system model of early warning and fail safe function. Based on this model, discusses the system design method for fatigue life. By using the life design of the suspender system have the following properties: (1) early warning and work with the fatigue life of derrick boom economic reasonable difference; (2) early warning of Suspender Damage, guarantee safety and overall structure work properly. Suspender improves reliability of suspender system safe operation. By adjusting the initial boom stress to achieve early warning and lifting The difference between rod fatigue life. The fatigue life is analyzed by using the traffic load, the warning function were evaluated. On the basis of the research on influence of suspender system damage on the fatigue life of the difference, further evaluation of the boom system model of early warning and safety can be damaged.

【学位授予单位】：大连海事大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U448.22

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