软土及近场主余震地震动作用下RC框架结构反应特征研究

发布时间：2018-09-08 15:22

【摘要】：历史地震资料表明约89%的强震发生后,强余震会在短时间内随之发生,余震地震动与主震地震动构成主余震序列型地震动。主震作用之后,强余震往往会引起结构的附加损伤,进一步加深震害,使结构和构件偏于不安全,进而造成了震害区域的人员伤亡和经济损失。软土场地地震动较硬土场地地震动有着显著不同的频谱特性,故其对结构的潜在破坏势也不尽相同。近场脉冲型地震动由于包含脉冲信号,其对结构的破坏也往往超过非脉冲型地震动。本文针对这一现象,选取Van Nuys Building为研究对象,研究了该结构在软土及近场主余震地震动作用下的反应特征及易损性。主要研究内容及结论如下:(1)通过对比分析数值模拟结果和传感器实测数据验证了Van Nuys Building的Open Sees有限元模型精度。(2)研究了该框架结构在软土主余震序列作用下的反应(顶点位移,最大层间位移角及最大残余层间位移角)特征,并对比分析了不同地震动强度输入次序对结构损伤的影响。结果表明:软土场地余震对结构的附加损伤远大于一般场地余震。当主余震强度较大时,软土场地结构反应程度更为剧烈。地震动强度输入次序差异会导致不同程度的结构损伤,代表主余震序列的逆次序地震动作用下的构件耗能普遍大于正次序地震动作用下的构件耗能;(3)研究了该框架结构在近场主余震序列作用下的反应特征。通过随机组合构造近场主余震序列,并研究了近场地震动极性(通过旋转地震动实现)对结构的影响。结果表明:近场脉冲型余震对于结构的附加损伤大于远场非脉冲余震且近场脉冲型主余震作用下的结构反应更为剧烈。余震的发生及强度增大会改变结构发生最大反应时所对应的角度。并且以不同反应指标衡量结构反应时,结果也不尽相同。(4)研究了该框架结构在软土及近场主余震作用下的易损性,并与一般场地及远场地震动对应的易损性进行了对比分析。结果表明软土余震及近场余震会显著增大结构的损伤超越概率,而一般场地和远场主余震作用下的结构易损性曲线在主余震发生前后相差不大。
[Abstract]:Historic seismic data show that about 89% of strong earthquakes will occur in a short period of time after strong aftershocks. Aftershocks and main earthquake ground motions constitute the main aftershocks. After the main shock action, strong aftershocks often cause additional damage to the structure, further deepen the damage, make the structure and components tend to be unsafe, and then cause seismic damage. The potential damage potential of soft ground motions to structures is different from that of hard ground motions. The damage of near-field impulsive ground motions to structures is often greater than that of non-impulsive ground motions because they contain impulsive signals. The main contents and conclusions are as follows: (1) The accuracy of Van Nuys Building's Open Sees finite element model is validated by comparing the numerical simulation results with the measured data of sensors. The response characteristics of the frame structure under the action of the main aftershock sequence in soft soil (the peak displacement, the maximum interlayer displacement angle and the maximum residual interlayer displacement angle) are analyzed and compared. The results show that the additional damage of the structure caused by the aftershock in soft soil is much greater than that caused by the general aftershock. When the earthquake intensity is large, the response of the soft soil structure is more intense. The difference of earthquake intensity input order will lead to different degrees of structural damage. The energy dissipation of the members under the inverse sequence of the main aftershock sequence is generally greater than that under the positive sequence of the earthquake. (3) The main aftershock near the field of the frame structure is studied. The response characteristics under the action of the sequence are studied. The near-field main and aftershock sequences are constructed by random combination, and the influence of near-field ground motion polarity (realized by rotating ground motion) on the structure is studied. It is more severe. The occurrence of aftershocks and the increase of intensity will change the corresponding angle of the structure when the maximum response occurs. And the results are different when the structural response is measured by different response indices. (4) The vulnerability of the frame structure under soft soil and near-field main aftershocks is studied, and the vulnerability corresponding to the general site and far-field ground motions is also studied. The results show that soft soil aftershocks and near-field aftershocks can significantly increase the damage transcendence probability of structures, while the vulnerability curves of structures under the main and far-field aftershocks have little difference before and after the main aftershocks.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.4

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