基于协整和多变量控制图的大型桥梁结构安全状态评估方法研究

发布时间：2018-02-23 23:31

本文关键词： 安全状态评估损伤识别影响效应协整多变量控制图　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：大型桥梁结构健康监测通过实时获取结构的劣化状况和及时预警,能降低桥梁的维护费用以及防止垮塌等突然性事故,已成为当今土木工程学科的研究前沿。运营状态下桥梁结构的响应受到环境温度、荷载等作用的影响,直接采用监测数据较难发现结构的损伤;同时因大型桥梁结构十分复杂,有限元模型的理论计算结果无法与实桥监测数据相符,导致基于恒定环境和有限元模型的安全状态评估很难应用于大型实际桥梁。本文根据桥梁结构在温度、荷载作用下各测点的应变、位移响应具有共同变化趋势的特点,基于协整理论建立影响效应的分离算法;根据损伤前后结构响应的统计量将发生改变的特点,采用多变量控制图来识别结构的损伤,避免了复杂的有限元建模以及理论计算与实桥测试不符的缺点,为健康监测在大型桥梁中的实际应用提供方法支撑。论文的主要研究内容和结果如下:①通过对大型桥梁中主要荷载作用类型的分析,将各种作用简化为集中荷载、均布荷载和温度荷载共三种作用。基于结构力学原理,推导三种作用下简支梁模型不同测点之间的挠度变化规律,结果表明在相同作用下,结构各点挠度之间呈线性变化趋势;②将结构响应的长期监测数据组成时间序列数据,采用Johansen方法确定数据的协整模型,通过模型计算的协整余量数据表示剔除影响效应后的结构响应数据,从而基于协整理论建立影响效应的分离方法。数值算例和有限元模型算例表明,该方法能有效分离温度、车辆荷载等影响效应;③通过对控制图中平均运行链长、均值变化量、平滑参数和控制线等参数取值的优化分析,采用协整余量数据建立基于多变量控制图的桥梁结构安全状态评估方法。在此基础上,通过对协整计算所包含传感器通道的取舍,提出单处和多处损伤部位的判断算法。数值算例和有限元模型算例的结果表明多变量控制图能识别结构单处及多处出现的损伤;④将影响效应分离方法和多变量控制图方法应用于某连续刚构桥中,通过长期监测的挠度、应变和温度数据对桥梁的安全状态进行评价,评价结果与人工检测结果一致,表明本文方法能成功应用于大型桥梁的结构安全状态评估。
[Abstract]:The health monitoring of large bridge structures can reduce the maintenance cost of bridges and prevent sudden accidents such as collapse by obtaining the deterioration condition and timely warning of the structures in real time. The response of bridge structure is affected by the environmental temperature and load, so it is difficult to find the damage of the bridge structure directly by using monitoring data, at the same time, because of the complexity of the large bridge structure, it is difficult to find the damage of the bridge structure directly by the monitoring data. The theoretical calculation results of the finite element model can not agree with the monitoring data of the real bridge, so it is difficult to apply the safety state evaluation based on the constant environment and the finite element model to the large practical bridge. The strain and displacement response of each measuring point under load has the characteristics of common changing trend. Based on the co-arrangement theory, the separation algorithm of influence effect is established, and according to the characteristic that the statistics of structural response before and after damage will change, The multivariable control chart is used to identify the damage of the structure, which avoids the disadvantages of complicated finite element modeling and theoretical calculation that does not agree with the actual bridge test. The main contents and results of this paper are as follows: 1. Through the analysis of the main load types in the large bridges, the functions are reduced to concentrated loads. Based on the principle of structural mechanics, the deflection variation law of simply supported beam model between different measuring points under three kinds of action is deduced. The results show that under the same action, The deflection of each point of the structure shows a linear change trend. The long-term monitoring data of the structural response are composed of time series data, and the cointegration model of the data is determined by Johansen method. The cointegration residual data calculated by the model represent the structural response data after the influence effect is excluded, and then the separation method of the influence effect is established based on the co-finishing theory. Numerical examples and finite element model examples show that the method can effectively separate the temperature. Through the optimization analysis of the average running chain length, mean variation, smoothing parameters and control line parameters in the control chart, the effects of vehicle load and so on are analyzed. Using cointegration allowance data to establish the bridge structure safety state evaluation method based on multivariable control chart. On the basis of this, the selection and selection of the sensor channel included in the cointegration calculation are made. The results of numerical examples and finite element model examples show that the multivariable control chart can identify the single and multiple damage sites of the structure, which will affect the separation of effects and multivariable control. The method of drawing is applied to a continuous rigid frame bridge. The safety state of the bridge is evaluated by the deflection, strain and temperature data of long-term monitoring. The evaluation results are consistent with those of the manual test, which indicates that the proposed method can be successfully applied to the structural safety state assessment of large bridges.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

【共引文献】