银川海宝塔动力特性测试及抗震性能分析

为了给银川市海宝塔的修缮保护工作提供参考依据，对其动力特性及结构损伤状况开展测试和数值模拟分析。首先对海宝塔的材料强度进行测试和计算，得出塔砌体的抗压强度及弹性模量；然后对该塔进行环境激励作用下的振动响应测试，得到塔东西和南北方向的1阶频率；最后建立数值模型并分析其模态与抗震性能，得到海宝塔的动力特性与地震作用下塔体各层的层间位移角，并基于砖石古塔破坏状态位移准则以及损伤指标开展损伤分析。结果表明：海宝塔东西方向和南北方向的1阶频率较为接近，但不同楼层的振动频谱曲线差异较大，尤其是峰值点数量；楼层越高，最大位移和层间位移角越大，受损也越严重；结构总体刚度退化较为严重，存在较大安全隐患，需进一步开展深入分析并采取保护措施。

Dynamic Characteristic Test and Seismic Performance Analysis of Haibao Pagoda in Yinchuan City

To provide a reference for the repair and protection of Haibao Pagoda in Yinchuan, the dynamic characteristics and structural damage condition of the pagoda were tested and analyzed by numerical simulation. The compressive strength and elastic modulus of the masonry of the pagoda were obtained by testing and calculating the strength of the pagoda materials. The pagoda vibration response under environmental excitation was tested, and the first-order frequencies of the pagoda in the east-west and north-south directions were obtained. A numerical model was established to analyze the vibration mode and seismic performance of the pagoda, and the dynamic characteristics and the story drift ratio of the pagoda under earthquake action were obtained. Then a damage analysis was carried out based on the displacement criterion of the failure state and the damage index of the pagoda. The results showed that the first-order frequencies of the east-west and north-south directions of the pagoda were close, but the vibration spectrum curves of different floors varied greatly, especially in the number of peak points; the higher the floor, the greater the maximum displacement and the story drift ratio, and the more serious the damage; the overall stiffness degradation of the structure was serious and there was a great potential safety hazard, which should be further analyzed and protected.