Flexural behavior of concrete filled non-uni-thickness walled rectangular steel tube

This paper presents an experimental study on the mechanical behavior of non-uni-thickness walled rectangular concrete-filled steel tube (CFT) beams subjected to pure bending. Three specimens were fabricated and tested to investigate the relation of bending moment vs. deflection of the composite beam. First, the ultimate flexural strength of non-uni-thickness walled rectangular CFT is compared to the predicted strength of corresponding uni-thickness walled CFT beams based on current design codes. Then a nonlinear finite element model is developed and verified with experimental results. The FEM model is used to investigate the effect of the steel wall thickness ratio on the bending strength of the composite beam. Both experimental and analytical results suggest that a non-uni-thickness walled rectangular CFT beam exhibits adequate ductility, and the flexural strength of a non-uni-thickness walled CFT beam is superior to that of a uni-thickness walled CFT beam.