Experimental Study On Increasing The Ductility Of Reinforced Concrete Shear Walls Strengthened By Carbon Fiber Sheet

In order to improve the ductility and strength of column, lateral confining is aneffective method. If columns are wrapped, carbon fiber sheet (CFS) can provideenough confining force. In this paper, the behavior of square columns, rectangularcolumns and reinforced concrete (RC) shear walls confined by CFS are studied. Theprogram includes two experimental researches as follows: 1. Research on the stress-strain curve of concrete columns confined by CFS. Thespecimens include two groups and are all under axial compression load. The firstgroup includes nine concrete square columns ,with the dimensions of 100mm×100mm×300mm,confined by CFS and three reference plain concrete squarecolumns. The influence of carbon fiber characteristic-value and initial axial force onthe behavior of CFS confined concrete is investigated. Experimental results indicatethat CFS can strengthen the strength and ductility of concrete evidently, and if theinitial axial stress is less than or equal to 0.3fc, difference between with and without itisn't too much. The second group includes three reference plain concrete rectangularcolumns, with the dimensions of 300mm × 100mm × 400mm , three concreterectangular columns segment confined by CFS and nine concrete rectangular columnssegment confined by CFS and high-strength bolts. The effect of those differentmethods on the behavior of CFS confined concrete is investigated. Experimentalresults indicate that the two different methods can improve strength and ductility ofcolumns effectively. Based on the experiment, an improved stress-strain curve ofsquare columns, and the relationship between the stress-strain curves of square andrectangular columns segment confined by CFS are proposed. 2. Experimental study on increasing the ductility of reinforced concrete (RC)shear walls strengthened by CFS. The response of one RC shear wall and three RCshear walls strengthened by CFS subjected to cyclic loading regime is investigatedexperimentally, and the axial compression ratios are 0.3,0.33,0.33,0.4. Experimentalresults indicate that when the concrete of RC shear walls' potential plastic hingeregions are confined effectively, its ductility can be evidently increased. Based on theexperiment, a ductility calculation method for shear wall is presented and a simplifieddesign formula is proposed. In order to meet the engineering requirements, a series ofshear wall with the same section is analyzed. Based on the above study, designrecommendations are proposed.