中、下承式拱桥吊杆载荷行为及安全性研究

【作者】 陈兵；

【导师】 罗特军；

【作者基本信息】 四川大学 ， 固体力学， 2003， 硕士

【摘要】 吊杆是中、下承式拱桥中连接拱肋与桥道系的关键构件，作用于桥道系上的恒、活载，通过吊杆传给拱肋，实现桥梁的跨越能力。由于受当前设计理论、科学技术和工业水平发展进程的制约，拱桥吊杆、吊具的设计、制造、安装、防护、服役、维护、健康诊断、修复拆换、设计寿命的确定乃至于服役一定时期后剩余寿命的预测等等，皆无明确、统一的规范。在大量的中、下承式拱桥吊杆设计、安装、维护、修复拆换过程中，主要依据设计者的主观判断，以致因吊杆失效造成的桥梁损坏和事故时有发生。为此，本文在参考、总结已有研究成果的基础上，结合西藏拉萨市柳梧大桥的设计工作，对吊杆的载荷行为及其安全性设计作了较为深入、全面的研究，提出了自己的观点并应用于实际工程设计中。 首先，本文在对吊杆在恒、活载作用下的静、动力行为作了分析、计算后认为：1．网状吊杆比平行吊杆、斜吊杆具有更为优异的力学性能；2．吊杆的内力随拱肋、桥道系、自身刚度以及荷载大小不同而呈非线性变化；3．安全系数取值应大于2.39；4．现行冲击系数取值偏小。 其次，本文对吊杆的疲劳问题作了较为详尽的阐述，说明疲劳失效是吊杆毁损的主要原因，证明了风(雨)及其它因素引起的吊杆锚固端最大弯曲应力约为其恒载内力的15％，提出了吊杆疲劳设计以及剩余寿命估算的具体方法和计算公式，论述了吊杆服役期内的防护、健康检测以及修复拆换的相应措施或解决办法。 最后，文章基于“破损安全”原则，对拉萨柳梧大桥的吊杆、吊具进行设计，并计算出吊杆的设计疲劳寿命。更多还原

【Abstract】 Suspenders, the key components of half through or through arch bridge connecting the arch rib and the deck, transfer the load from the deck to the arch rib for the arch bridge’s spanning function. Because of the constraint in science and technology and of the development level of industry today, there is yet no definite and uniform criterion in suspender’s and anchorage’s design, manufacture, fixing, protection, service, maintenance, health diagnosis, remove and repair, ascertaining service life and predicting remain life, etc. It is mainly depended on designer’s estimation in the course of suspender design, fixing, maintenance and remove and repair, so it is happened frequently that bridge demolishment and accident owing to the suspender failure. Therefore, in this paper, the suspender’s load behavior and safety design are studied particularly on the basis of other researches and the study and design of LaSa LiuWu bridge, and the answers are put forward and applied in designFirstly, the suspender’s static and dynamical properties are analyzed and calculated under the dead load or live load in this paper, and the conclusions are made as follows: 1. Reticulate suspender’s mechanical properties are better than inclined and parallel suspender’s. 2. Internal force of the suspender varies nonlinearly with the rigidity of itself, the arch rib and the deck. 3. The safety factor had better greater than 2.39. 4. Current impact factor is lower.Secondly, this paper discusses the fatigue of suspender in detail, explaining that fatigue failure is the main reason of the demolishment of the suspender, proving that the bend stress of the suspender’s anchorage caused by the wind, rain, and so on is 15% of its internal stress caused by the dead load, putting forward the method and the formula of the suspender’s fatigue design and remain life estimate , andillustrating the measure of the suspender’s protection in its service life, health monitoring and remove and repair.Finally, according to the principle of damage-safety, the suspenders of LaSa LiuWu bridge are designed, and their fatigue life calculated.更多还原