碳纤维增强钢筋混凝土框架柱的界限轴压比和延性分析

Analysis on Limit Values of Axial-Load Ratio and Ductility of Reinforced Concrete Columns Strengthened with CFRP Sheets

以新抗震设计规范为依据,分析并推导出碳纤维增强钢筋混凝土框架柱截面在界限破坏条件下的轴压比,研究了纵筋、箍筋和碳纤维布对柱轴压比限值和延性限值的影响.研究结果表明,纵筋等级越高,界限轴压比越小;箍筋和碳纤维布的体积配箍率越大,界限轴压比越大;现有公式不适用于约束混凝土柱在高轴压比下发生大偏心受压破坏时位移延性比的计算,因此对高轴压比下约束混凝土柱的延性性能需进一步研究.

In the earthquakeresistant design, the axialload ratio on the cross sections of the columns should be limited in order to protect the columns from destroying in the shear failure and to ensure the ductility of the columns. The paper analyzed and deduced the axialload ratio on the cross sections of the reinforced concrete columns strengthened with carbonfiberreinforced plastic (CFRP) sheets under the conditions of the limit destroy; and further studied the influences of the longitudinal reinforcement, the transverse reinforcement, the CFRP sheets on the limit values of the axialload ratio and the ductility of the columns. The result stated that the axialload ratio under the conditions of the limit failure decreases with the yield strength of longitudinal reinforcing bars and increases with ratio of the volume between transverse reinforcing bars and CFRP sheets and concrete. Moreover, the current equation of ductility ratio can not be used to evaluate ratio of lateral ductility of concrete columns confined by transverse reinforcement under conditions of the flexural failure of high axialload ratio, so the ductile property of concrete columns confined under that case should be studied more.