增大截面法加固震损钢筋混凝土框架的抗震性能试验研究

Experimental study on seismic behavior of earthquake-damaged RC frame strengthened by enlarging cross-section

为研究已震损及未损钢筋混凝土框架采用增大截面法加固后的抗震性能,按照1/2缩尺制作4榀两层双跨钢筋混凝土框架模型,其中1榀为原型对比框架,1榀直接加固,另外2榀进行不同程度的预损后采用增大截面法进行加固,对所有框架模型进行低周反复破坏试验。试验结果表明,经过对震损及未损钢筋混凝土框架采用增大截面法进行合理和可靠的加固,框架结构的承载力有较大程度的提高,并且具有良好的延性变形和耗能性能,震损程度对加固框架的刚度、强度退化以及耗能性能未产生明显影响。对于混凝土框架结构而言,无论从承载力、延性、耗能及对震损的加固修复等各方面来看,采用钢筋混凝土增大截面法是一种非常有效的抗震加固方法,可以满足"小震不坏、中震可修、大震不倒"的抗震要求。

To study the seismic behavior of earthquake-damaged and undamaged RC frame strengthened by enlarging cross-section, four two-story and two-span RC frame models with 1/2 scale were designed and produced. One model was prototype control frame, one was strengthened by enlarging cross-section without pre-damage, and the other two were strengthened after pre-damage. Then, the low-cycle and repeated load was imposed on these models until they failed. The experimental results show that （1） after reasonable and reliable reinforcement by enlarging cross-section, all specimens with and without earthquake-damage had significant improvements on the ultimate bearing capacity, while maintaining good ductile deformation and energy dissipation ability; （2） the earthquake damages had no obvious effect on stiffhess degradation, strength degradation and energy dissipation ability. For reinforced concrete fi＇ame structure, from the aspect of bearing capacity, ductility, energy dissipation, strengthening effect and so on, enlarging cross-section is a very effective seismic strengthening method, which can meet the seismic requirement of ＂no damage under minor earthquakes, repairable under moderate earthquakes and no collapse under severe earthquakes＂.