中小跨径混凝土桥梁的性能与维护策略研究

发布时间：2018-08-28 08:39

【摘要】：目前我国公路桥梁已超过70万座,其中中小跨径混凝土桥梁在我国得到广泛应用,占桥梁总数的90%以上。在复杂交通环境及车辆荷载的作用下,桥梁结构性能将逐渐退化、破损、钢筋锈蚀、耐久性降低,严重影响桥梁的安全运营。本文以中小跨径混凝土桥梁为研究对象,对在役桥梁的性能进行了深入的研究,主要分析了浙江衢州地区中小跨径混凝土桥梁的现状,提出了桥梁性能状态的评估方法,重点进行了四片既有预应力混凝土空心板梁静动力性能的试验研究,最后给出了桥梁的性能维护策略。主要研究内容及成果如下： 1)对衢州地区在役中小跨径混凝土桥梁的性能状况进行详细调查,对中小跨径桥梁的上部结构类型、荷载等级、技术状况、主要病害类型进行详细分析,并对病害产生的综合性原因进行分析。 2)在充分考虑桥梁性能状态评估中的模糊性和不确定性的基础上,提出了基于云理论的桥梁性能状态评估方法。通过实例应用,验证了本文方法的合理性,为桥梁性能状态的评估提供了一种新方法。 3)通过对四片既有20m标准跨预应力混凝土空心板梁进行从弹性至构件破坏的加载试验研究,发现该类PC空心板梁在使用11年后,仍具有很好的延性。试验研究和非线性有限元分析结果验证了现行桥梁规范给出的承载力计算公式是合理的。在受剪试验加载工况下,该试验梁的配筋设计一般是正截面受弯破坏先于斜截面受剪破坏,斜截面抗剪承载力相对较大。 4)分别通过数值计算与试验研究分析无噪声和实测有噪声下,预应力混凝土梁破坏过程中的振动特性。采用龙格-库塔法求解试验梁振动偏微分方程,获得试验梁在力锤激励下动力响应,对所得信号进行HHT时频分析；对实测信号进行HHT变换获得试验梁破坏过程中各损伤阶段下的瞬时频率-加速度幅值曲线。瞬时频率-加速度幅值曲线对应的损伤特征频率的变化反映了试验梁在破坏过程中的损伤程度的变化。 5)分别选取状态指标和可靠度指标作为性能维护指标,并研究其劣化模型及其维护策略。建立维护策略优化模型,以寿命周期维护成本最小为目标函数,并考虑多级性能水准的要求制定最优的维护加固策略,给出不同性能水准下桥梁寿命周期的维护优化策略。
[Abstract]:At present, there are more than 700000 highway bridges in China, in which small span concrete bridges are widely used in China, accounting for more than 90% of the total number of bridges. Under the action of complex traffic environment and vehicle load, the performance of bridge structure will be degraded gradually, damaged, steel bar corroded and durability reduced, which seriously affects the safe operation of bridge. This paper takes medium and small span concrete bridge as the research object, deeply studies the performance of the existing bridge, mainly analyzes the present situation of the small and medium-sized span concrete bridge in Quzhou, Zhejiang Province, and puts forward the evaluation method of the bridge performance state. The static and dynamic behavior of four existing prestressed concrete hollow slab beams is studied. Finally, the performance maintenance strategy of the bridge is given. The main research contents and results are as follows: 1) the performance of existing small and medium span concrete bridges in Quzhou area is investigated in detail, and the superstructure type, load grade, technical status of medium and small span bridges are analyzed. The main disease types are analyzed in detail, and the comprehensive causes of the disease are analyzed. 2) on the basis of considering the fuzziness and uncertainty in the evaluation of bridge performance, Based on cloud theory, a bridge performance evaluation method is proposed. The rationality of this method is verified by an example. This paper provides a new method for evaluating the performance of bridges. 3) the loading test of four prestressed concrete hollow slab beams with existing 20m standard span from elastic to member failure is carried out. It is found that the PC hollow slab beam still has good ductility after 11 years of service. The experimental results and nonlinear finite element analysis results verify the calculation formula of bearing capacity given by the current bridge code is reasonable. Under the loading condition of shear test, the reinforcement design of the test beam is usually that the flexural failure of the normal section is prior to the shear failure of the oblique section. The shear bearing capacity of oblique section is relatively large. 4) the vibration characteristics of prestressed concrete beams in the process of failure are analyzed by numerical calculation and experimental study respectively under noise-free and measured noise-free conditions. The Runge-Kutta method is used to solve the vibration partial differential equation of the test beam. The dynamic response of the test beam under the excitation of the force hammer is obtained, and the HHT time-frequency analysis of the obtained signal is carried out. The instantaneous frequency-acceleration amplitudes of the test beam in each damage stage were obtained by HHT transform. The change of the damage characteristic frequency corresponding to the instantaneous frequency-acceleration amplitude curve reflects the change of the damage degree of the test beam during the failure process. 5) the state index and the reliability index are selected as the performance maintenance index, respectively. The deterioration model and its maintenance strategy are also studied. The maintenance strategy optimization model is established, the minimum maintenance cost of the bridge life cycle is taken as the objective function, and the optimal maintenance and reinforcement strategy is formulated considering the requirements of multi-level performance level, and the maintenance optimization strategy for the bridge life cycle under different performance levels is given.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.7

【参考文献】