| Title |
Elasto-Plastic Flexural Behavior of Steel-Concrete Composite Column Base Employing Cast Steel Base Plate |
| Authors |
Chung Jin-An ; Yang Il-Seung ; Choi Sung-Mo |
| Keywords |
Column Base ; Anchor Bolts ; Cast Steel ; Composite Column ; Rotation Stiffness |
| Abstract |
This paper deals with the experimental work with the objective to gain a better understanding of the elasto-plastic behavior of steel-concrete composite column bases under seismic loading. Seven specimens were tested to investigate structural behavior of steel-concrete composite column bases. The specimen consisted of concrete filled steel tube (CFT) column (or steel tube column), reinforced concrete footing beam, high base unit of cast steel and 4 high strength anchor bolts. The following main influential elements were taken into consideration: axial load level and type of column (CFT or empty steel tube, rectangular section or circular section). Specimens were subjected to cyclic seismic lateral loading at the column tops under constant axial load. The cyclic lateral load was applied according to a predetermined sequence of rotation angle cycles of column base. Experimental results verified that the rotation stiffness and flexural strength of CFT column base calculated according to the formulas given by this paper were in coincidence with the test results in cases of lower axial load without reference to the type of column. For the specimens under higher axial load, formulas underestimated their rotation stiffness and flexural strength. The comparison indicates that several modifications should be taken into consideration in column base design formulas of steel structure in order to make effective use of these formulas in CFT column base design, especially for column bases under higher axial load. It is made clear that ultimate flexural strength of this kind column base can be evaluated by ultimate strength with the coefficient of bearing stress of concrete taken into account. |