STUDY ON THE EFFECTS OF AXIAL COMPRESSION RATIO ON SEISMIC CAPACITY OF PRESTRESSED CONCRETE FRAME
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摘要: 由于预应力混凝土(PC)框架结构自身的特点,当采用我国现行规范规定的普通钢筋混凝土柱的轴压比限值进行设计时,往往会造成框架柱截面尺寸较小,在地震作用下结构形成典型的层间屈服机制而破坏;而过分限制轴压比,又会导致设计中柱的截面尺寸由轴压比确定,柱的配筋则由构造配筋率确定,即:柱子的截面尺寸较大导致建造成本上升而经济性不佳,合理地确定柱轴压比已成为PC框架工程设计中的必需。依据我国现行规范设计设防烈度为8度(0.2g)区的6榀不同轴压比PC框架,采用基于性能的抗震分析评估理论,研究各轴压比下PC框架的耗能屈服机制及轴压比对PC框架抗震能力的影响,初步探讨PC框架轴压比限值的合理性与经济性。分析表明,进一步降低现行规范中的轴压比限值,能够较好地保证PC框架在罕遇地震作用下的抗震能力。Abstract: Because of its own characteristics of a prestressed concrete frame,when prestressed concrete frame isdesigned by the limit of column axial compression ratio in current common reinforced concrete codes,the columnsection size is usually small,an interlayer yielding mechanism will form in the structure so as to suffer the severedamage under earthquake. In the other hand,excess emphasis on the limit of axial compression ratio will lead to thecost up. This paper carried out research on the yielding mechanism of prestressed concrete (PC) frames in differentaxial compression ratios and the effects of axial compression ratio on the seismic capacity of the PC frames designed bythe current codes based on PBSD. The rationality and economy of the limited values of axial compression ratio of thePC frames were discussed. The analysis results show that an improvement of the limited values of axial compressionratio of the PC frames can ensure the seismic capacity of prestressed concrete frame under rare earthquake.
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Key words:
- prestressed concrete frame /
- axial compression ratio /
- seismic capacity /
- pushover
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