發(fā)布時間：2018-03-18 06:19

  本文選題：基礎隔震結構　切入點：反應譜　出處：《蘭州理工大學》2016年碩士論文　論文類型：學位論文

【摘要】：基礎隔震技術在過去二十多年來經歷了多場大地震考驗,成為國內外最熱門的一項抗震技術,并且在包括我國在內的多個國家進入大面積推廣階段。反應譜對認識結構地震響應規(guī)律、校核結構分析結果有著重要的作用。反應譜的平均特性與震源機制,場地條件,震級,震中距等眾多因素有關。其中,震源機制作為地震動的影響因素,不僅能夠影響反應譜的譜值還能夠影響反應譜曲線的形狀,進而在結構的抗震設計中起到重要的作用。因此,本文圍繞震源機制對隔震結構反應譜的影響展開了以下幾方面的工作:(1)采用雙自由度體系分析模型,研究譜的類型及上部結構阻尼比對隔震結構反應譜的影響。以ATC-63報告建議的選取原則選取了22條地震記錄,以此為激勵,利用狀態(tài)空間法建立了隔震層的真譜與擬譜,并通過改變上部結構的阻尼比建立了不同阻尼比的反應譜。對比分析后,結果表明在研究隔震結構的反應譜時,不可用擬譜來代替真譜;以及在建立隔震結構的反應譜時,需確定上部結構的材料,從而確定上部結構阻尼比;(2)采用非比例阻尼,研究震源機制對隔震結構線彈性反應譜的影響。在Ⅱ類場地條件下,選取605條地震記錄作為統(tǒng)計樣本,按照地震記錄類型及震源機制進行分組,運用狀態(tài)空間法得到了在近場及遠場地震作用下的加速度、位移及能量反應譜。采用標準化和平均化的方式研究了反應譜的特性,并運用分段線性擬合的方法給出了設計反應譜的表達式,該表達式可以反映震源機制等因素對反應譜的影響作用,最后通過對某實際基礎隔震工程進行算例驗證,將計算結果與抗震規(guī)范進行對比,結果表明本文提出的表達式更為安全、合理,可將其應用于基礎隔震結構的抗震設計中;(3)采用Bouc-Wen模型描述隔震支座的非線性行為,研究震源機制對隔震結構彈塑性反應譜的影響。運用狀態(tài)空間法及四階龍格-庫塔法得到近場及遠場地震作用下的彈塑性反應譜,對反應譜特性進行分析之后,運用曲線擬合的方法給出了反應比譜(彈塑性反應譜與線彈性反應譜譜值比與周期的關系)的表達式。該表達式可反映震源機制等因素對反應譜的影響作用。利用該表達式可在線彈性反應譜的基礎上快速獲得結構的彈塑性響應。最后通過有限元模型進行了算理驗證。結果表明:該式在進行隔震結構的彈塑性地震反應分析時具有良好的計算精度。
[Abstract]:In the past 20 years, the foundation isolation technology has been tested by many large earthquakes, and has become the most popular seismic technology at home and abroad. The response spectrum plays an important role in recognizing the seismic response law of structures and checking the results of structural analysis. The average characteristics of response spectra and the focal mechanism, site conditions, magnitude, etc. The focal mechanism, as an influential factor of ground motion, can not only affect the spectral value of the response spectrum but also the shape of the response spectrum curve, and thus play an important role in the seismic design of the structure. In this paper, according to the effect of focal mechanism on response spectrum of isolated structures, the following work is carried out: 1) A two-degree-of-freedom system analysis model is used. The types of spectrum and the effect of damping ratio of superstructure on response spectrum of isolated structures are studied. Based on the selection principle of ATC-63 report, 22 seismic records are selected, and the true spectrum and pseudo-spectrum of isolation layer are established by state space method. By changing the damping ratio of superstructure, the response spectra of different damping ratios are established. The results show that pseudo spectrum can not be used instead of true spectrum when studying the response spectrum of isolated structure, and when the response spectrum of isolated structure is established, the response spectrum of isolated structure can not be replaced by pseudo spectrum. The material of superstructure should be determined, and the damping ratio of superstructure should be determined by adopting non-proportional damping. The effect of focal mechanism on the linear elastic response spectrum of isolated structures is studied. 605 seismic records are selected as statistical samples under the condition of class 鈪，

本文編號：1628342