Experimental Study Of Retrofitting Light-weight Masonry Infilled RC Frames Seriously Damaged By Earthquake With CFRP

Worldwide, a common type of construction is lowrise and midrise reinforcedconcrete buildings with light-weight masonry walls filling the spaces bounded by theirstructural frames. For the past years, these constructions suffer varying degrees ofdamage because of their different seismic resistances in several large earthquakes. But aconsiderable amount of the constructions damaged in the earthquake could continue touse after repair and retrofit. Therefore, the study of the method and effect of repairingand retrofitting the damaged constructions after the earthquake is really and urgentlyneeded. In recent years, Fiber Reinforced Polymer (FRP) has been widely applied in theseismic strengthening of concrete structures because of its advantages of light weight,high strength, corrosion resistance, easy construction, etc. FRP was applied to retrofitthe damaged construction in this research, and the feasibility and effect of repairing andretrofitting the damaged light-weight masonry infilled RC frames by Carbon FiberReinforced Polymer (CFRP) were investigated in this article, which had an importantguiding significance in promoting the application of CFRP in retrofitting the damagedconstruction.Two full-scale light-weight masonry infilled RC frame specimens damaged in theinitial quasi-static test were studied in this article, the details of the research arefollowing.(1)The program of repairing and retrofitting the specimens was designed in thisarticle, which contained the selection of specimens for retrofitting, the scheme ofrepairing, and the principle of retrofitting with CFRP. The pasting method, position andquantity of CFRP sheet were decided according to the principle and the correspondingcodes. The two full-scale specimens had been repaired and retrofitted according to theprogram.(2)The program of quasi-static test was designed according to the condition ofretrofitted specimens in this article, which contained instrumentation, test set-up, andloading procedure. And then the two retrofitted specimens were subjected to the similarquasi-static test and the details of test process were recorded.(3)Comparisons and contrasts of the seismic behaviors, such as failure pattern,hysteretic curve, skeleton curve, stiffness, ductility, energy, etc. between the initialundamaged specimens and the corresponding repaired and retrofitted ones werediscussed in this article. And the comprehensive evaluation and estimation of thefeasibility and effect of repairing and retrofitting were given then.It was concluded from this article’s research that the seismic behaviors, especiallyductility, of the repaired and retrofitted specimens were better than that of thecorresponding initial undamaged ones. And the negative correlation existed between the effect of retrofit and the degrees of damage.