砖石古塔结构动态损伤演化与抗震性态评估研究

Evaluation of seismic performance of masonry pagodas is one of the key issues of seismic protection to masonry pagodas. To form the quantificational evaluation of seismic performance of masonry pagodas, it is necessary to study the mechanical behavior process of structures affected by earthquake. In the projection, the theory of damage development involved, the breakage of structure material and damage property affected by earthquake are described based on damage theory. And the key scientific issues such as the damage development, seismic disaster mechanism and evaluation of seismic performance of masonry pagodas are settled with the dynamical test and shaking-table test are done. The follows are in detail:1.The damage development equation of structure material of masonry pagodas is set up to study the characters and rules of damage development.2.The historic seismic breakage and response of masonry pagoda are analyzed to study the damage development mechanism of the process of seismic disasters of structure.3. Based on the disciplinarian of damage development of structures of masonry pagodas affected by earthquake, the seismic performance level and evaluation index systems of structure are researched to constitute the seismic performance evaluation model of masonry pagodas. Furthermore, the quantificational relation to evaluation index and damage variable of structures is studied. By the works above, the mechanisms of breakage and damage development of masonry pagodas are brought forward and the evaluation method of seismic performance of is founded. That can provide scientific theoretical basis for seismic protection to masonry pagodas.

抗震性态评估是砖石古塔建筑抗震保护的核心科学问题之一，建立砖石古塔抗震性态的定量评估方法，需进行地震作用下古塔结构的力学行为研究。项目基于损伤理论，引入损伤演化概念，表征古塔结构材料性能劣化及地震作用下结构损伤特性，进行结构动力测试及振动台模型试验，并应用数值分析方法，解决砖石古塔结构损伤演化、震害机理及抗震性态评估的关键科学问题。主要工作为：（1）建立砖石古塔结构材料的损伤演化方程，研究地震作用下古塔结构的损伤演化特性；（2）进行砖石古塔地震反应分析及历史震害反演分析，研究砖石古塔结构震害形成过程的损伤演化机理；（3）依据地震作用下砖石古塔结构损伤演化的规律，研究结构抗震性态水准及评估指标体系，建立砖石古塔抗震性态评估模型，并分析宏观评估指标与结构损伤演化特征参量的关系。通过研究，提出地震作用下砖石古塔结构破坏机制及损伤演化机理，建立其抗震性态评估模型，为古塔抗震保护工作提供科学的依据。

砖石古塔是优秀的历史文化遗产建筑，开展地震作用下砖石古塔结构损伤破坏机制研究，阐明砖石古塔地震损伤演化机理，建立古塔抗震性态评估模型，是砖石古塔保护的基础研究之一。针对砖石古塔动态损伤基本问题，结合结构病害调研，进行了6座古塔的原位动力测试，得到了结构的动力特性，通过古塔结构受力单元力学性能试验确定计算参数，并建立数值模型进行结构动力特性计算，通过对比动力特性试验与计算结果完成了古塔整体损伤分析；进行了玄奘塔结构模型振动台试验，测试了不同加载工况条件下结构的位移及加速度反应，完成了古塔结构地震反应分析与地震损伤演化分析；结合部分古塔抗震能力分析，建立了砖石古塔抗震性态评估模型，确定了指标体系及取值标准。主要研究内容及成果包括：（1）砖石古塔结构整体损伤识别与损伤定位方法：将小雁塔、兴教寺测师塔、基师塔及崇寿寺塔结构动力特性的测试结果与数值计算结果进行对比，进行古塔结构动力特性分析，依据动力特性进行结构整体损伤评定、损伤程度判定、损伤定位分析，得到了结构整体损伤率及损伤位置，为砖石古塔结构损伤识别与判定奠定了基础。（2）砖石古塔结构地震响应及损伤模式：考虑场地地基条件，建立地基与结构相互作用体系的数值模型，计算地震作用下玄奘塔、慈灯寺金刚宝座塔的动力响应，完成玄奘塔振动台试验及地震损伤分析，得到不同工况条件下结构动力放大效应及结构损伤破坏的基本特征，提出实心结构古塔地震损伤演化的基本模式。（3）砖石古塔抗震性态评估模型及指标体系：建立砖石古塔抗震性态评估模型，确定评估指标体系及其取值标准，对慈灯寺塔、玄奘塔及崇寿寺塔进行了抗震性态评估，得到了古塔抗震性态综合评估指数并确定了结构抗震薄弱部位，为砖石古塔抗震性态评估提供了依据。研究成果为古塔建筑本体监测及安全评估工作提供了科学的依据，为砖石古塔抗震研究奠定了理论基础，对世界文化遗产建筑的保护具有重要的参考价值。