1998 Fiscal Year Final Research Report Summary
Seismic Performance of Reinforced Concrete Columns Confined in Square Steel Tube with Thin Steel Wall
| Project/Area Number |
09650630
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Building structures/materials
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
SAKINO Kenji Human-Environment Studies, KYUSHU UNIVERSITY,Professor, 人間環境学研究科, 教授 (70037985)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YUPING Sun Human-Environment Studies, KYUSHU UNIVERSITY,Associate Professor, 人間環境学研究科, 助教授 (00243915)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Keywords | Tubed column / Square steel tube / Width to wall-thickness ratio / Cyclic shearing force / Axial load level / Shear capacity / Flexural capacity / Deformation capacity |
|---|
| Research Abstract |
In the experimental phase of research, total of twenty-three reinforced concrete columns confined in square steel tube (tubed columns) were subjected to cyclic shearing force and deformed in a double curvature pattern. The experimental parameters were aspect ratio of column (2.0-4.0), width to wall-thickness ratio (B/t=28- 117), and magnitude of axial load. The following conclusions are reached on bases of the research.
1. The failure modes of tubed columns with aspect ratio of 2.0 and 4.0 are shear failure and flexural failure, respectively. It is noteworthy that lateral deformation capacity is greatly enhanced with the decrease in Bit ratio and with the decrease of axial load level even in the short columns failed in shear.
2. The flexural strengths of columns can be satisfactorily evaluated using the simplified method that utilizes the equivalent stress block based on the stress-strain model for confined concrete proposed by Sakino and San. They should be enhanced using a factor that takes the effect of extra confinement from end stubs into consideration.
3. The lateral load capacities, as dominated by shear, for short column specimens can be fairly evaluated using AIJ-A method, which is analytical method based on plastic theory, although it underestimates the capacity of specimens with large lateral steel ratios. On the other hand, the Arakawa's empirical shear formula also can be used.
|
