摘要
依据我国规范设计4榀不同预应力度、抗震等级为二级的预应力混凝土框架结构,基于Open Sees分析软件,采用纤维梁、柱单元对其进行数值建模,对一榀单层单跨预应力混凝土框架的低周反复加载试验进行数值模拟,滞回曲线和骨架曲线与试验结果吻合良好,验证了该数值建模方法的实用性;在此基础上,对4榀预应力混凝土框架进行了静力弹塑性分析;最后,对按我国规范设计的抗震等级为二级的PC框架结构,在裂缝控制等级为二级时,预应力梁中非预应力筋用量的确定方法及其适用性进行了理论分析。结果表明:按我国现规范设计的预应力混凝土梁中非预应力筋用量偏多,在大震下预应力混凝土框架结构难以实现"强柱弱梁"的破坏模式,底层柱底塑性铰出现过早;适当提高梁端截面的预应力度值,能够在一定程度上改善结构的屈服机制,增大结构的整体位移延性,提高结构的抗震能力。因此,建议在进行相关规范修订时,适当减少非预应力筋配筋、提高框架梁的预应力度限值,如按04规程设计的二级预应力混凝土框架结构,其预应力度限值可提高至0.8。
Four models of PC flame structures with different prestressing ratio designed according to the current aseismic codes in our country were established in OpenSees software based on fiber section element. Firstly, the numerical pseudo-static analysis of a single span PC flame was performed, and the comparison between the experimental and numerical results demonstrated the accuracy of the numerical model. Then, static elasto-plastic analysis were conducted on each PC flame model on OpenSees platform. For the prestressed concrete beams designed by secondary-crack control level, the amount of non-prestressed reinforcement was investigated theoretically. The analytical results show that PC frames are difficult to achieve 'strong column and weak beam' failure mode under strong earthquakes and plastic hinges appear prematurely at the bottom of column. A reasonable increase in the prestressing ratio could improve the yield mechanism, increase the structural ductility and enhance the structural seismic capacity. Therefore, the paper suggests that the prestressing ratio should beincreased to 0.8 for PC frames.
出处
《工程力学》
EI
CSCD
北大核心
2017年第2期129-136,共8页
Engineering Mechanics
基金
国家自然科学基金项目(51278218)
关键词
预应力混凝土框架
预应力度
抗震性能
静力弹塑性分析
强柱弱梁
prestressed concrete frame structure
prestressing ratio
seismic capacity
Pushover analysis
strongcolumn and weak beam