本文關(guān)鍵詞： 失效模式 RC框架結(jié)構(gòu) Pushover分析 塑性鉸 延性系數(shù)　出處：《長沙理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：強(qiáng)震作用下,框架結(jié)構(gòu)的延性變形能力與它的失效模式密切相關(guān)。5.12汶川地震后的震害調(diào)查發(fā)現(xiàn),大量現(xiàn)澆鋼筋混凝土(RC)框架結(jié)構(gòu)的破壞形式為柱端破壞較梁端破壞嚴(yán)重,框架呈現(xiàn)出“強(qiáng)梁弱柱”的失效模式。而按我國建筑抗震設(shè)計規(guī)范所預(yù)期的“強(qiáng)柱弱梁”失效模式在RC框架中未能實現(xiàn)。從震害中可以看出,以“強(qiáng)梁弱柱”失效模式破壞的框架延性明顯要比“強(qiáng)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(shè)計時,彈塑性地震力降低系數(shù)R對設(shè)防烈度地震作用的折減實際上決定了結(jié)構(gòu)的屈服水準(zhǔn)和延性需求的大小。而我國規(guī)范對不同延性能力的結(jié)構(gòu)均取用相同的R值,即R=2.86。根據(jù)R-μ-T關(guān)系,這使得某些“強(qiáng)梁弱柱”失效模式下的框架延性能力達(dá)不到規(guī)范所預(yù)期的延性需求,從而導(dǎo)致基于現(xiàn)有規(guī)范設(shè)計的RC框架結(jié)構(gòu)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(xiàn)“強(qiáng)梁弱柱”導(dǎo)致框架延性差的現(xiàn)象與RC框架柱設(shè)計可靠性較低有關(guān)。為了闡明此現(xiàn)象的原因,對比分析了隨機(jī)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(biāo)。結(jié)果表明了按我國2001版抗震規(guī)范設(shè)計的RC大偏壓柱抗震承載力可靠指標(biāo)取值偏低是影響結(jié)構(gòu)延性的重要因素。(2)在SAP2000中建立有、無現(xiàn)澆樓板的框架結(jié)構(gòu)模型分別來模擬罕遇地震作用下“強(qiáng)梁弱柱”與“強(qiáng)柱弱梁”兩種不同的失效模式。根據(jù)Pushover分析得到的結(jié)構(gòu)基底剪力-頂點位移曲線、能力譜和需求譜曲線以及結(jié)構(gòu)的塑性鉸發(fā)展過程,對比兩種不同失效模式下延性系數(shù)的變化規(guī)律并進(jìn)行R-μ關(guān)系分析,進(jìn)而揭示當(dāng)“強(qiáng)柱弱梁”失效模式較難實現(xiàn)時我國抗震設(shè)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(xué)位授予單位】：長沙理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU375.4

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相關(guān)期刊論文 前1條

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本文編號：1454245