结构近场地震作用及抗弯钢框架近场地震反应分析

发布时间：2019-01-09 08:19

【摘要】：近场地震的特殊作用效应会对工程结构造成毁灭性的破坏,进而带来大量的人员伤亡和巨大的经济损失。先进的抗震设计方法应具有保护近场区结构的特点,近场地震动的特性及其对结构的影响引起了越来越多学者的关注。《建筑抗震设计规范》GB50011规定：对处于发震断裂两侧10km以内的结构,地震动参数应计入近场影响,5km以内宜乘以增大系数1.5,5km以外宜乘以不小于1.25的增大系数。此规定没有考虑近场地震动频谱的特殊性,只是粗略地同步放大了远场地震固定形状反应谱的谱值来提高近场设计地震作用,在条文解释中也未提出依据,少有文献讨论此增大系数的安全性和合理性。本文以抗弯钢框架为研究对象,按照抗震规范将地震作用分别乘以增大系数1.5和1.25,设计3层、6层钢框架结构。本文选取了15条带有明显速度脉冲的近场地震波,建立了近场地震波的反应谱,并与规范设计反应谱进行了比较,表明近场地震波反应谱的加速度敏感区更宽,指出对规范设计反应谱进行修改的必要性。对所设计的抗弯钢框架进行了弹塑性时程分析,评估了结构在近场地震下的反应。结果表明：近场脉冲效应增大了结构的顶点位移、层间位移、基底剪力和层间剪力；设计地震作用采用增大系数1.5时,对3层结构偏保守,对6层结构偏不安全；设计地震作用采用增大系数1.25时,对3层、6层结构都偏不安全。建议对于不同周期结构,设计时应采用不同的增大系数,或采用近场地震设计反应谱。
[Abstract]:The special effect of near-field earthquake will cause destructive damage to engineering structure, and then bring a large number of casualties and huge economic losses. Advanced seismic design methods should have the characteristics of protecting near-field structures. The characteristics of near-field ground motion and its influence on structure have attracted more and more scholars' attention. The Code for aseismic Design of buildings "GB50011" stipulates that the parameters of ground motion should be taken into account in the near field effect for structures located within 10km on both sides of the seismogenic fault. Within 5km it is appropriate to multiply the coefficient of increase by a factor of not less than 1. 25. The coefficient of increase is not less than 1. 5 ~ 5 km. This regulation does not take into account the particularity of near-field ground motion spectrum, but roughly amplifies the spectral value of the far-field seismic response spectrum of fixed shape in order to improve the near-field design seismic action, and there is no basis in the interpretation of the articles. Few literatures discuss the safety and rationality of this coefficient. In this paper, the flexural steel frame is taken as the research object. According to the seismic code, the seismic action is multiplied by the increasing coefficient 1.5 and 1.25 respectively, and the 3-story and 6-story steel frame structure is designed. In this paper, 15 near-field seismic waves with obvious velocity pulses are selected, and the response spectra of near-field seismic waves are established. The results show that the acceleration sensitive region of the near-field seismic response spectrum is wider than that of the gauge design. The necessity of modifying the design response spectrum is pointed out. The elastic-plastic time-history analysis of the designed steel frame is carried out and the response of the structure under near-field earthquake is evaluated. The results show that the near field pulse effect increases the vertex displacement, interstory displacement, basement shear force and interstory shear force of the structure, and when the seismic effect is 1.5, it is conservative for the three-story structure and unsafe for the 6-story structure. When the factor of increasing the seismic action is 1.25, it is not safe for the structures of three or six stories. It is suggested that different increasing coefficients or near-field seismic response spectra should be used in the design of structures with different periods.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU311.3;TU391

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