基于抽柱法的无粘结预应力装配式框架结构连续倒塌分析

PROGRESSIVE COLLAPSE ANALYSIS OF UNBONDED POST-TENSIONED PRECAST RC FRAME STRUCTURES USING COLUMN REMOVAL METHOD

为研究无粘结预应力装配式框架结构的防连续倒塌性能,首先采用有限元软件OpenSees中的梁柱节点单元模拟无粘结预应力梁柱节点,并与试验结果进行对比,然后采用抽柱法对一栋6层无粘结预应力装配式框架结构和现浇框架结构进行连续倒塌分析,得到了抽柱后关键构件的内力时程曲线和失效点的竖向位移时程曲线,最后模拟了无粘结预应力装配式框架结构和现浇框架结构的连续倒塌过程。研究结果表明:在抽除中柱后,无粘结预应力装配式框架结构的倒塌荷载极限值比现浇框架结构高24.2%;在抽除边柱后,无粘结预应力装配式框架结构的倒塌荷载极限值比现浇框架结构则高35.7%。在柱截面尺寸和配筋相同、梁截面尺寸和受弯承载力相同的情况下,无粘结预应力装配式框架结构防连续倒塌性能优于现浇框架结构。

To study the behavior of beam-column joints and the progressive collapse performance of unbonded post-tensioned precast concrete frame structures, finite element models were established in OpenSEES and compared with experimental results. With the established beam-column joint models, a six-story unbonded post-tensioned precast concrete frame and a cast-in-place concrete frame with similar structural configurations were simulated. Progressive collapse analysis was performed for these two kinds of frames using column removal method. Results of the numerical analysis show that, with the interior column removed, the ultimate load at failure of the post-tensioned precast frame is 24.2% higher than that of the cast-in-place frame; the percentage increased to 35.7% if an exterior column is removed. Removal of an exterior column is more likely to cause a progressive collapse than removal of an interior column. The results also show that with the same reinforcement layout of the column and the same flexural capacity of the beam, the post-tensioned precast RC frame exhibit better collapse-resisting performance than the cast-in-place RC frame.