| Title |
An Experimental Study on Behavior Properties of Concrete Filled Steel Tubular Stub-Column under Axial Force |
| Abstract |
Recently the tendency of urban structure is becoming high-rised by increase in land price and effective use of land in restricted space. Also the development of new structure system is required to plan maximized space use and to overcome structural restriction in past according to variegated and complicated a structure.Under these background, especially concrete filled steel tube system is spotlighting for structural system in nowadays. If concrete filled steel tubes are used for structural member, it is increased in load carrying capacity and plastic deformation capacity by reciprocal confine of steel tube and concrete and have an advantage to increase fire-resistance properties and to confine local buckling of steel tube. Especially these members have to superior in structural properties than the other section type, when used to compressive members.Accordingy this study investigated to properties of structural behaviors through a series of experiment with the key parameter, such as diameter-to-thickness(D/t) ratio and strength of concrete.From the experiments, the obtained results are summarised as follow.(1)The restraint effect of filled concrete by steel tube was increased respectively as the D/t ratio and the strength of concrete decrease.(2) The increase ratio of ultimate capacity of concrete filled steel tube was increased the extent of twice as much as 1.3~2.1, compared with those of the hollow steel tube and these increase ratio was significantly as the increase of D/t ratio and the strength of filled concrete.(3) The experiment results for ultimate capacity of concrete filled steel tubular column were increased the extent of twice as much as 1.07~1.22, compared with those of the calculated value with superimposed strength and these increase ratio was presented larger as the D/t ratio and the strength of concrete decrease.(4) The empirical formula to predict the strength of comfined concrete by steel tube was proposed.(5) The empirical formula to predict the ultimate capacity of concrete filled steel tubular column to superimpose yielding strength of steel tube on obtained maximum strength of confined concrete with restraint coefficient was proposed. |