Abstract
The reinforcing method with diagonal reinforcements in multi-directions for circular R/C columns were proposed by the authors. The proposed reinforcing method for these columns [MXRC] is composed of the spiral hoops having a superior ductility for high axial load and the diagonal reinforcements having a superior strength for lateral load. To investigate the confinement effectiveness of the spiral hoops, seismic loading tests were conducted. In this test, six test units were tested, and the variable investigated were the amount of the spiral hoops and axial load. Experimental and analytical results are as follows. 1) Ultimate shear strength of MXRC with enough spiral hoops increase by the confinement effectiveness rather than them with a little spiral hoops. 2) Ultimate shear strength calculated by the superposition strength theory gives fairly good agreement with the experimental tesult.
