碳纤维布加固混凝土框架受力性能

为了避免纤维布拉断、剥离等提前破坏模式,提出了铝角钢/FRP加固框架结构梁、柱端部的新型加固方法.介绍了两跨两层框架试件的几何、配筋、加固过程和试验方法.通过比较分析,选择合适的应力-应变模型以模拟FRP对混凝土的约束效应,截面的弯矩-曲率关系近似地采用带软化段的四折线型,对加固后的框架进行非线性分析,与试验结果作了对比.最后,研究了混凝土约束效应、加固长度、合理选择待加固杆件对加固框架受力性能的影响.数值分析结果与试验结果吻合良好,FRP产生的约束效应对框架受力有较大影响,适当选择加固长度和加固量,可以实现塑性铰或破坏面位置的转移,特别加强薄弱的杆件,可以取得显著的加固效果.

Mechanical behaviour of RC frames strengthened by CFRP sheets

To avoid the premature failure modes,such as peeling and rapture of laminates,a new strengthening method using aluminum angle and CFRP(carbon fiber reinforced polymer)sheets systems is proposed,which can strengthen the ends of beams and columns of RC frames.Firstly,the reinforcement,aluminum angle and CFRP sheets details of two spans,two levels RC frame specimen and the test setup are introduced.Secondly,a stress-strain model fitting to FRP-confined concrete is selected.The moment-curvature relationships are simplified into quadrilinear form with curvature-softening behaviour,and nonlinear static analysis is carried out to examine the behaviour of the frame specimen.Lastly,the effects of confined concrete,selecting length and members to reinforce on the behaviour of the strengthened frames are studied.The numerical results agree well with the test results and show that the effect of confined concrete on the performance of the strengthened frames shouldn't be ignored,the position of plastic hinges and failure sections could be shifted from the ends of beams or columns by proper selection of strengthening length and content of FRP sheets,and rational selection of strengthening members could notably improve the performance of strengthened frames.