LAUSR

Abstract This paper presents new empirical methods to theoretically predict bending moment capacity (Mu) and flexural stiffness values at the initial and serviceability levels (Ki and Ks) of concrete-filled steel tube (CFST) composite beams. A wide range of results for Mu, Ki, and Ks covering various parameters of CFST beams are required to develop these empirical methods. Therefore, 144 numerical CFST models were developed in this study using finite element software. The adequacy of the newly developed empirical methods was validated with the results obtained from previously reported experimental and numerical studies conducted by other researchers. For example, using the new methods, mean values of 0.967 and 0.996 were achieved from the ratios of predicting Mu values to the previously reported values of the rectangular and circular CFST beams, respectively. The mean values were 1.074 and 1.050 from the predicted Ki, and Ks values, respectively. Furthermore, the results of these new methods were compared with the results obtained by the most commonly used standards and methods in this field, namely, EC4, AISC, AIJ, BS5400, and others.