Experimental Research On Uniaxial Compressing Structure Member With Composite Strengthening

In recent years, retrofitting and strengthening of RC structures by fiber-wrapping and steel-bonding has become increasingly popular, but it has not be seen in foreign and native literature that concrete columns are strengthened with the combination of two materials mentioned in above.A brief introduction of some strengthening methods and the characteristics of CFRP, and the research status in quoin repair and rehabilitation of concrete structures is stated. Strengthened with Carbon Fiber Reinforced Plastic (CFRP), angle iron and a combination of them, and in partial loads, 10 rectangular concrete columns under axial compression are tested in this paper. The performing characteristic and confinement mechanism of confined columns are demonstrated in details. The influence of failure type, the ultimate strength, stress-strain relationship, stiffness and ductility of reinforced-concrete columns strengthened with externally bonded different materials were researched and analyzed , which can give reference to application. A satisfying conclusion that strengthening with a combination of the two materials is an effective and economically measure is acquired.Firstly, the making of specimen and the corresponding experimental devices are introduced, which includes the dimension, number, testing methods, opration proceduced of the testing machine, and the steps of rehabilitation are introduced. Secondly, the experimental results of concrete columns confined with CFRP, angle iron and the combination of them are analyzed and induced. The experimental curves of results are given, a brief introduction of this experiment is stated, the procedures of fractures in the columns are analyzed, the stress is analyzed in aspects of ultimate bearing capacity, stress-strain relationship, ect. And then, based on finite element analysis, three kinds of calculating model are presented to predict respectively the ultimate strength of concrete columns confined with CFRP, angle iron and the combination of them, two new methods for cal-culting bearing capacity of columns confined with diffreent methods are put forward. In the last chapter draws a conclusion from the whole research and takes a look into the firthcoming work in this field. From the results of the experimental research, we know that the angle iron and CFRP are well coordinated, and that the mechanical property, the beating capacity and the resistance capacity to deformation are all well improved when the RC columns strengthened with combination of angle iron and CFRP. This strengthening means could used in practicable effectively. In this paper, the experimental results of the structural members strengthened in partial initial loads are analysed only, and this strengthening means should be further studied.