| Title |
New Method to Estimate the Strength of Concrete Filled Tube Beam-Columns based on AISC/LRFD |
| Authors |
Choi Young-Hwan ; Bae Kyu-Woong |
| Keywords |
Concrete Filled Tube ; Beam-columns ; Design Equations ; Interaction Curve |
| Abstract |
This paper presents a new design method to estimate the strength of concrete filled tube beam- columns based on the current AISC/LRFD method that is known to provide an over-conservative estimation. The flexural strength based on the current AISC/LRFD is considerably underestimated. The over-conservativeness of the current AISC/LRFD method comes mainly from neglecting the contribution of the concrete in flexure and the different behavior of composite beam-columns from pure steel beam- columns. Assuming full composite action, the new method reported herein idealizes the P-M interaction curve with two lines as in the current AISC method; however, the lines intersect at a point where a maximum moment occurs. Based on the new method, modified AISC P-M interaction equations for square CFT columns subjected to combined axial load and single axis bending are formulated in a companion paper. The interaction curves by the new approach shows greatly improved results. |