古塔结构损伤的系统识别Ⅱ:应用

System Identification for Structural Damage of Ancient Tower II: Application

大多数系统识别方法并不能很好地解决实际工程所呈现的复杂性和随机性 .本文的研究目的是提出可有效应用于实际工程、基于系统识别的损伤检测及估计方法 .文中以兴福寺塔为例 ,讨论了古建筑结构损伤的特点 ;提出了根据满足规范要求的设计目标确定基准系统的方法 ,从而使系统识别技术在古建筑这样一类没有损伤前测试数据的实际工程的应用成为可能 .实测频率和模态数据被用来对结构参数的变化作出估计 ,采用论文I提出的判别分析法和条件分布下的损伤程度估计方法对古塔损伤进行了识别 ,其结果是可以接受的 .

Most system identification methods do not represent the complexity and uncertainties one would encounter when dealing with actual engineering problems. The purpose of the present study is to propose an improved damage detection and assessment approach, established on the basis of the method of system identification that can be effectively used in real structural projects. Using Xingfu temple tower as an example, the particularities of damage identification for ancient buildings are discussed in this paper. An approach to determine the baseline system according to the design goal that satisfies the current code requirements is proposed. This paves the way for the possible use of the system identification techniques in cases like ancient building structures for which no data for the undamaged state are available. The measured natural frequencies and modal shapes of Xingfu temple tower are used in the estimation for decrease in stiffness parameters. The application of the distinguish analysis method and the approach to assess the degree of damage under conditional distributions proposed in paper I on the particular ancient tower is found to lead to acceptable results.