本文關鍵詞： 失效模式 RC框架結構 Pushover分析 塑性鉸 延性系數　出處：《長沙理工大學》2014年碩士論文　論文類型：學位論文

【摘要】：強震作用下,框架結構的延性變形能力與它的失效模式密切相關。5.12汶川地震后的震害調查發(fā)現,大量現澆鋼筋混凝土(RC)框架結構的破壞形式為柱端破壞較梁端破壞嚴重,框架呈現出“強梁弱柱”的失效模式。而按我國建筑抗震設計規(guī)范所預期的“強柱弱梁”失效模式在RC框架中未能實現。從震害中可以看出,以“強梁弱柱”失效模式破壞的框架延性明顯要比“強柱弱梁”失效模式下的框架延性差。按我國建筑抗震規(guī)范設計時,彈塑性地震力降低系數R對設防烈度地震作用的折減實際上決定了結構的屈服水準和延性需求的大小。而我國規(guī)范對不同延性能力的結構均取用相同的R值,即R=2.86。根據R-μ-T關系,這使得某些“強梁弱柱”失效模式下的框架延性能力達不到規(guī)范所預期的延性需求,從而導致基于現有規(guī)范設計的RC框架結構偏于不安全。本文針對此問題,完成的核心工作如下：(1)本文研究發(fā)現“強梁弱柱”導致框架延性差的現象與RC框架柱設計可靠性較低有關。為了闡明此現象的原因,對比分析了隨機偏心距下我國2010版與2001版抗震規(guī)范RC大偏壓柱抗震承載力可靠指標。結果表明了按我國2001版抗震規(guī)范設計的RC大偏壓柱抗震承載力可靠指標取值偏低是影響結構延性的重要因素。(2)在SAP2000中建立有、無現澆樓板的框架結構模型分別來模擬罕遇地震作用下“強梁弱柱”與“強柱弱梁”兩種不同的失效模式。根據Pushover分析得到的結構基底剪力-頂點位移曲線、能力譜和需求譜曲線以及結構的塑性鉸發(fā)展過程,對比兩種不同失效模式下延性系數的變化規(guī)律并進行R-μ關系分析,進而揭示當“強柱弱梁”失效模式較難實現時我國抗震設計規(guī)范采用定值R=2.86的不足。
[Abstract]:Under strong earthquake, the ductile deformation ability of frame structure is closely related to its failure mode. The failure of a large number of cast-in-place reinforced concrete (RC) frame structures is more serious at the end of columns than at the end of beams. The frame shows the failure mode of "strong beam and weak column", but the failure mode of "strong column and weak beam" as expected in the code of seismic design of our country can not be realized in RC frame, which can be seen from the earthquake damage. The ductility of frame with "strong beam weak column" failure mode is obviously worse than that with "strong column weak beam" failure mode. The reduction of elastic-plastic seismic force reduction coefficient R actually determines the yield level and ductility demand of the structure, and the same R value is used for the structures with different ductility capability in our code. According to the R- 渭 -T relation, the ductility capacity of some frame under the failure mode of "strong beam and weak column" can not reach the expected ductility requirement of the specification. As a result, the RC frame structure designed based on the existing specifications is less secure. This paper aims at this problem. The main work of this paper is as follows: 1) in this paper, it is found that the poor ductility of frame caused by "strong beam and weak column" is related to the low reliability of RC frame column design. In order to clarify the reason of this phenomenon. The reliability index of seismic bearing capacity of RC columns with large eccentric load under random eccentricity of China 2010 edition and 2001 edition seismic code is compared and analyzed. The results show that the RC large eccentric columns are designed according to the earthquake resistant code of 2001 edition of China. The low reliability index of aseismic bearing capacity is an important factor affecting the ductility of the structure. (. 2) in SAP2000. The model of frame structure without cast-in-place slab is used to simulate "strong beam weak column" and "strong column weak beam" under rare earthquake respectively. According to the Pushover analysis, the shear-vertex displacement curve of the base of the structure is obtained. The capacity spectrum and demand spectrum curves and the plastic hinge development process of the structure are compared, and the R- 渭 relation is analyzed by comparing the ductility coefficient of the two different failure modes. Furthermore, it is revealed that when the failure mode of "strong column and weak beam" is difficult to realize, China's seismic design code has the disadvantage of adopting fixed value R ~ (2.86).
【學位授予單位】：長沙理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU375.4

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本文編號：1454245