基于标准能量冲击载荷下的桥梁结构力学性能研究

发布时间：2018-05-31 03:34

  本文选题：冲击系数 + 动态响应　； 参考：《中国民航大学》2014年硕士论文

【摘要】：目前常用的桥梁结构检测方法可分为：静载试验法、动载试验法。静载试验法发展较早，相关理论、技术比较成熟，但存在检测成本高、耗费时间长、需要中断交通等缺点。动载试验法检测成本低、检测时间短、无需中断交通，能够快速准确对桥梁结构力学性能做出分析，但是动载试验法发展较晚，部分理论及测试技术尚不成熟。通过动载试验方法对桥梁结构做出快速准确的分析是目前桥梁结构检测研究的热点。 在河北省交通科技基金项目、国家超级计算天津中心（NSCC）以及安世亚太公司的共同支持下，本文对如何通过动载试验方法对桥梁结构承载能力做出快速评价进行研究。基于静载试验中利用结构校验系数对桥梁承载能力进行评价的方法，提出依据动载试验位移值和桥梁结构冲击系数计算静载试验位移值，从而达到通过动载试验方法获取桥梁结构校验系数的目的，实现结构承载能力快速评价。 桥梁结构动位移值可通过高精度传感器获得，而冲击系数的影响因素很多，，各因素间关系复杂。因此，本文对桥梁结构动态响应下冲击系数问题进行了详尽分析，研究了车辆行驶速度、桥面平整度、桥梁结构刚度、桥梁结构形式对冲击系数的影响。针对桥面平整度现场准确测量难度大、随机性强以及对冲击系数影响不可忽略的难题，提出标准能量冲击试验方法即采用标准加载车匀速通过桥梁并在跨中位置进行跳车。计算结果表明，跳车试验能够有效压制平整度对冲击系数的影响，通过此方法获得的冲击系数仅与桥梁结构刚度及桥梁结构形式有关。 跳车试验的本质是通过跳车的大冲击作用压制桥面不平整引起的小冲击作用。因此，跳车试验导致桥梁结构产生剧烈振动，冲击系数较大。跳车高度为5-15cm时有限元分析得到的桥梁结构跨中位移冲击系数约是通常情况下冲击系数的2-3倍。针对这一问题，进行了大量室内跳车试验及现场桥梁跳车试验，试验结果验证了有限元分析方法的准确性。 依据有限元分析得到的跳车条件下冲击系数与桥梁一阶频率的关系式。通过测量桥梁结构一阶频率和动位移信号就可实现桥梁结构静位移的快速计算，为使用校验系数法评价桥梁结构承载能力提供了新途径。
[Abstract]:The commonly used bridge structure testing methods can be divided into static load test method and dynamic load test method. The static load test method was developed earlier, and the related theory and technology are mature, but it has the disadvantages of high detection cost, long time consumption and the need to interrupt traffic. The dynamic load test method has the advantages of low cost, short detection time, no need to interrupt traffic, and can analyze the mechanical properties of bridge structure quickly and accurately. However, the dynamic load test method is developed late, and some theories and testing techniques are not mature. Rapid and accurate analysis of bridge structure by dynamic load test method is the hot spot of bridge structure detection. With the support of Hebei Communication Science and Technology Foundation, National Super Computing Tianjin Center (NSCCC) and Anshi Asia Pacific Company, this paper studies how to quickly evaluate the bearing capacity of bridge structure by dynamic load test method. Based on the method of evaluating the bearing capacity of the bridge by using the check coefficient of the structure in the static load test, the displacement value of the static load test is calculated according to the displacement value of the dynamic load test and the impact coefficient of the bridge structure. Thus, the purpose of obtaining the check coefficient of bridge structure by dynamic load test method is achieved, and the rapid evaluation of bearing capacity of bridge structure is realized. The dynamic displacement of bridge structure can be obtained by high precision sensor, but the impact coefficient has a lot of influence factors, and the relationship between each factor is complex. Therefore, the impact coefficient of bridge structure under dynamic response is analyzed in detail, and the effects of vehicle driving speed, deck smoothness, bridge structure stiffness and bridge structure form on impact coefficient are studied in this paper. Aiming at the difficult problem of accurate measurement of bridge deck smoothness on the spot, strong randomness and the influence on impact coefficient, a standard energy impact test method is put forward, that is, the standard loading vehicle is used to pass the bridge at uniform speed and jump at the mid-span position. The results show that the effect of smoothness on the impact coefficient can be suppressed effectively, and the impact coefficient obtained by this method is only related to the stiffness of the bridge structure and the form of the bridge structure. The essence of jumping test is to suppress the small impact caused by bridge deck unevenness. Therefore, the jump test results in violent vibration of the bridge structure and high impact coefficient. When the jump height is 5-15cm, the displacement impact coefficient of bridge structure is about 2-3 times higher than that under normal conditions. In order to solve this problem, a large number of indoor jumping tests and field bridge jumping tests have been carried out, and the accuracy of the finite element analysis method has been verified by the test results. According to the finite element analysis, the relation between the shock coefficient and the first order frequency of the bridge is obtained. By measuring the first order frequency and the dynamic displacement signal of the bridge structure, the fast calculation of the static displacement of the bridge structure can be realized, which provides a new way to evaluate the bearing capacity of the bridge structure by using the check coefficient method.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3

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