Estimation Equation for Horizontal Load Bearing Capacity of Circular PCFST with Diaphragm

The purpose of this study is to propose a practical formula for estimating the maximum load bearing capacity partially concrete-filled steel tubes (PCFST) without using complicated numerical analysis and estimation procedures. This focused on four parameters (radius thickness ratio R, slenderness λ, axial force n, concrete filling Lc/L) used in determine horizontal buckling position PCFST with diaphragms under monotonic loading. Based results, an equation was obtained by nonlinear regression analysis. that did not consider different positions predicted error approximately ±10% from numerically analyzed values, but took into consideration could predict within margin about 5% value determining advance.