杜东升, 宋宝玺, 许伟志, 王曙光. 高层钢结构考虑长周期地震动的减震加固研究[J]. 工程力学, 2020, 37(7): 189-200. DOI: 10.6052/j.issn.1000-4750.2019.09.0508
引用本文: 杜东升, 宋宝玺, 许伟志, 王曙光. 高层钢结构考虑长周期地震动的减震加固研究[J]. 工程力学, 2020, 37(7): 189-200. DOI: 10.6052/j.issn.1000-4750.2019.09.0508
DU Dong-sheng, SONG Bao-xi, XU Wei-zhi, WANG Shu-guang. SEISMIC RETROFIT OF A HIGH-RISE STEEL STRUCTURE CONSIDERING LONG-PERIOD AND LONG-DURATION GROUND MOTIONS[J]. Engineering Mechanics, 2020, 37(7): 189-200. DOI: 10.6052/j.issn.1000-4750.2019.09.0508
Citation: DU Dong-sheng, SONG Bao-xi, XU Wei-zhi, WANG Shu-guang. SEISMIC RETROFIT OF A HIGH-RISE STEEL STRUCTURE CONSIDERING LONG-PERIOD AND LONG-DURATION GROUND MOTIONS[J]. Engineering Mechanics, 2020, 37(7): 189-200. DOI: 10.6052/j.issn.1000-4750.2019.09.0508

高层钢结构考虑长周期地震动的减震加固研究

SEISMIC RETROFIT OF A HIGH-RISE STEEL STRUCTURE CONSIDERING LONG-PERIOD AND LONG-DURATION GROUND MOTIONS

  • 摘要: 考虑长周期地震动的影响对一高层钢结构进行了减震加固,并对其抗震性能进行了评估。日本东京新宿地区一高层钢结构经历了“3·11”地震,其强震观测系统记录到了有价值的加速度时程数据,为使其成为人流密集区域的避难场所,拟进行减震加固以提高其抗震性能。基于记录数据进行了频谱分析和时频域分析,发现此次地震具有明显的远场长周期和长持时特征,其长周期分量持续到300 s后才逐渐衰减;利用Ai分布地震力研究了结构的非线性特征和损伤分布,并在此基础上采用基于存储刚度的静力分析方法进行了减震优化设计;选取了包含记录数据在内的长周期长持时地震动和一般地震动对减震加固结构进行了非线性动力分析及损伤评估。结果表明:相较于一般地震动,长周期长持时地震动作用下高层结构的减震效果更明显,优化后的减震加固方案使结构的振动衰减较快,不仅减小了结构的最大响应,而且有效降低了构件的损伤数量和损伤程度。衡量钢支撑局部屈曲的累积轴向应变在长周期长持时地震动作用下明显大于一般地震动,故长周期长持时地震动对钢支撑局部屈曲影响较大。

     

    Abstract: Considering the influence of long-period and long-duration ground motions, a high-rise steel structure is retrofitted and its seismic performance is assessed. The high-rise steel structure located in Shinjuku, Tokyo of Japan, experienced “3·11” earthquake and its acceleration data was recorded by a strong earthquake monitoring system. To make it an emergency shelter, we proposed 2 retrofit schemes to improve its seismic performance. The recorded data is analyzed by a spectrum analysis method and a time-frequency domain analysis method, and it is revealed that the earthquake has an obvious far-field long-period and long-duration characteristics and the long-period component lasts for 300 s before gradually weakening. Inelastic characteristics and potential damage distributions are analyzed using Ai-distribution seismic design forces, and then the static analysis method based on storage stiffness is used for optimized damping design. We selected long-period and long-duration ground motions including the recorded data and one normal ground motion to conduct inelastic dynamic analysis and damage assessment. Compared with the normal ground motion, the damping effect of the high-rise structure subjected to long-period and long-duration ground motions is more obvious. The optimized retrofit scheme makes the vibration decay quickly, which reduces the maximum response of the structure and the damage degree of the structural members. As for steel braces, the cumulative axial strain which can examine local buckling is significantly larger subjected to long-period and long-duration ground motions than that of the normal ground motion. Therefore, we should pay more attention to the local buckling of braces when considering long-period and long-duration ground motions.

     

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