基于GFRP加固的RC梁柱结构抗连续倒塌性能研究

Study on progressive collapse behavior of RC beam-column structures strengthened by GFRP

为了探究钢筋混凝土(RC)梁柱结构梁上部截断钢筋用玻璃纤维布(GFRP)加固抵抗连续倒塌的作用。设计了2个一层四跨梁柱结构模型,梁的上部钢筋分别按截断与GFRP加固进行布置。通过OpenSees软件对结构连续倒塌过程进行数值分析。通过比较两个模型外加荷载、梁中轴力、梁关键截面应力来分析GFRP布加固结构抗连续倒塌的效果。结论是用GFRP加固对结构连续倒塌梁机制阶段影响较小,但对结构悬链线机制阶段影响较大。按经典弹塑性理论计算的塑性峰值荷载比模拟值偏小;加固布置结构的最终承载力比截断布置的提高16.45%,梁上部截断钢筋用GFRP加固可以明显提高结构在悬链线机制阶段抗连续倒塌能力。

In order to explore the effect of the upper truncated steel bar strengthened by GFRP sheets of the reinforced concrete beam-column structure to resist progressive collapse, two one-layer and four span beam-column structures whose steel bars in the upper of beams were truncated or strengthened by GFRP sheets were designed. In this paper, the numerical analysis of the process of progressive collapse of the structure is carried out by OpenSees software. By comparing the applied load, the axial force of beam and the stress of the critical beam section, the paper obtains the effect of structure strengthened by GFRP sheets to anti-collapse resistance of structures. The results show that the structure strengthened by GFRP has a slight effect on the beam mechanism, but has a significantly influence on the catenary mechanism;the plastic peak load calculated based on the conventional plastic theory is smaller than the analog value;the ultimate bearing capacity of structure strengthened by GFRP sheets has improved by 16.45% comparing with the structure designed by truncated steel bars;and the upper truncated steels bars strengthened by GFRP sheets can obviously enhance anti-collapse ability of structures on the catenary mechanism.