Abstract
A composite bridge column with steel tubes combined with reinforced concrete, has been developed aiming at not only high speed construction but also skilled labor savings especially for high colums with 40 to 100m height. This bridge column has some significant structural features, i. e. 1) several steel tubes are placed in the reinforced concrete section, 2) steel tubes with external spiral ribs are utilized for anchorage and 3) PC strands are wound instead of lateral rebar. The present study has indicated effectiveness of the new type bridge colum by conducting a bond test of steel tubes with external spiral ribs and a cyclic horizontal loading test with a colum model designed on the basis of an actual bridge colum to be constructed. Followings are concluded: 1) bond strength of 68kgf/cm2 which is around three times the allowable stress was obtained in the bond test, 2) flexural loading capacity of 84tf which is further larger than 64tf, calcurated value by the superposed equation, was provided in good agreement with a predicted value based on the beam theory in assumption of perfect bond action between concrete and steel tubes, 3) superior displacement ductility and absorbed energy characteristic were obtained in comparison with the RC specimen.
