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近断层脉冲型地震动和远场类谐和地震动是两类特殊的长周期地震动,对这两类地震动作用下长周期结构特别是超限结构响应的对比研究还很少。以集集地震动记录为数据基础,各选取10条具有代表性的近断层脉冲型地震动记录和远场类谐和地震动记录,首先对两类地震动的频谱特性进行了对比研究,分析了两类地震动的特点,在此基础上,以所选取的这两类地震动分别作为输入,对一个超限高层结构分别进行了8度(0.2g)多遇水准地震作用下的弹性时程分析和罕遇水准地震作用下的弹塑性时程分析,并对两类特殊长周期地震动作用下的结构位移响应和加速度响应结果做了比较研究。结果表明,近断层脉冲型地震动和远场类谐和地震动作用下结构的最大层间位移角都接近规范限值甚至超出限值,远场类谐和地震动作用下的结构位移响应和加速度响应都大于近断层脉冲型地震动输入下的相应响应。因此,对长周期结构进行抗震性能分析时,选择远场类谐和地震动更加偏于安全。
Near-fault impulsive and far-field harmonic earthquakes are two types of special long-period earthquakes. There are few comparative studies on the response of long-period structures, especially over-limit structures, to these two kinds of earthquakes. Based on the records of the Jiji earthquake, we selected 10 records of near-fault impulsive and far-field harmonic ground motions. The spectral characteristics of the two types of ground motions were compared and analyzed Based on these two types of ground motions, respectively, as inputs, the elastic behavior of an overrun high-rise structure subjected to an earthquake of more than 8 degrees (0.2g) The analysis of the elasto-plastic time-history under the action of rare earthquakes and rare-level earthquakes shows that the displacement response and the acceleration response of two special long-period earthquakes are comparatively studied. The results show that the maximum inter-story drift angle of near-fault ground motions and far-field harmonic earthquakes are both close to the standard limit and even beyond the limits. The structural displacement responses under far-field harmonic ground motion The acceleration response is greater than the corresponding response under near-fault impulsive ground motions. Therefore, in the analysis of seismic performance of long-period structures, the choice of far-field harmonic ground motion is more biased towards safety.