Experimental Research On The Behaviors Of Reinforced Concrete Cracked Short Columns Strengthened With CFRP

Firstly, in the text, described the present research condition of reinforcing concrete structure in our country, and all kinds of strengthening method were introduced simply, and then described the dint characteristics and the present anti-earthquake research condition of the reinforced concrete short columns. Short columns often appear in the structure design; which occur brittleness in the earthquake or other outside dint function, and break for brittleness. But many short columns were only damaged to appear crack in the earthquake, and the damaged condition still comes short of the degree that can not be reinforced. Therefore, it is necessary to carry on a reinforcing research for crack short columns and raise their anti-vibration ability. CFRP reinforced concrete structure as a kind of new technique applied in the our country more than 10 years, it has many advantage than other reinforcing methods, particularly suited for anti- earthquake reinforcing, but there are also many problems that need to be studied for making CFRP reinforcing technique to get a further extensive application in the structure engineering.For this, a method of strengthening crack concrete short columns under an existing lotus with sticking CFRP is put forward in the paper.To investigate their seismic behaviors under different crack width and different axial compression ratio, four specimens, one contrast specimen and three short columns strengthened with CFRP,which were tested subjected to low cycle reversed loads.Research expresses that the anti-vibration of the short collums after reinforcing can have the exaltation of different degree, the high-degree fasten with the crack width and the axial compression ratio of short columns.There was a different degree contrast with no crack short columns, its anti-sheared loading dint and ductility to lower 30% respectively and 40%~50% under other same conditions.The"truss-arch"model theory was used to analyze the mechanism of strengthened crack-short columns, the strength loss coefficientνCFRP after strengthening with CFRP were computed. The CFRP strength reduce of taking the crack short columns compared with the research that the CFRP reinforce no-crack short columns has very great difference, at the same time the surplus loading of the concrete crack-short columns were computed.Based on the experiment and the theory analysis, the simple formula of shear bearing capacity was put forward for sticking CFRP to strengthen concrete short columns, Compared with experiment results, the calculated results showed good agreement.