SEICMIC STRENGTHENING OF RECTANGULAR R/C COLUMNSCONFINED BY CIRCULAR STEEL- AND CF-JACKETS

摘要

During the recent destructive earthquakes in Japan and other earthquake countries, a largenumber of brittle shear failure, flexural compression failure and crushing by high axialcompression have been observed in reinforced concrete (R/C) rectangular columns in buildingstructures as shown in Figs. 1, 2 and 3. On the contrary, if the R/C rectangular columns areconfined laterally by steel plates (SP) or carbon fiber (CF) sheets, then brittle shear failure can beprevented and the column can develop its ultimate flexural moment capacity (Yoshimura [1], [2],[3]). Herein, in order to investigate the effectiveness of the seismic strengthening methods byusing circular steel plate- or CF sheet-jackets for existing R/C rectangular columns, ten differentcolumns with and without jacketing are tested under different constant high axial compression of13.2MPa and 19.4MPa, and alternately repeated lateral forces. Results of the experiment indicatethat the ultimate flexural strength and deformation capacity of the R/C rectangular columnswhich are confined laterally by the circular cross-sectional steel plate- and CF sheet-jacketing arequite effective, especially when the columns are subjected to high axial compression.