| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Research Abstract |
The purposes of this research are to obtain the ultimate strength and the plastic deformability of concrete filled and covered steel tube columns with several material combinations and to seek the optimum material combinations. Ordinary and/or high strength concrete (Fc=240kg/cm^2 and Fc=500kg/cm^2) are used for covered and filled steel tube columns. And columns have circular tubes with large or small diameter, or wide flange sections at the center respectively.
Test specimens are sub-assemblages of cruciform consisted of columns and beams. They are loaded with repeated bending moments, which corresponds to severe seismic loadings, as well as vertical loading, 30% of axial force capcity of the columns simultaneously.
It is obtained from the experiment results that the generalized additional strength equations of columns can evaluate the ultimate strength of concrete filled and covered steel tube columns satisfactorily, even using high strength concrete. However, for columns using wide flange sections, it overestimates usually, and the ultimate strength of concrete outside of hoop reinforcement should be considered to be fc'=0.2fc. Moreover, the plstic deformability of columns with concrete filled and covered steel tube with larger diameter and with smaller diameter were judged to be considerably high, which corresponds to FA to the structural rank I and FB to the structural lank respectively defined with Japanese Building Standard Law.
Consequently, as the conclusions the ultimate strength of concrete covered and filled steel tube columns can be estimated with the generalized additional equations satisfactorily. And these columns are ductile to seismic forces.
|
