Research on the load-displacement hysteretic behavior of concrete-filled thin-walled cold-formed square steel beam

Six concrete-filled thin-walled cold-formed square steel tubes beams in cyclically loading were tested.The author researched the failure mode,analysed the load-displacement hysteretic curves and its frameworks curves through the experiment.Some different parameters of earthquake resistant capability can be reviewed,such as hysteretic behavior and ductility.Some important conclusions can be drew as follows: ⑴The shape of load-displacement hysteretic curves of concrete-filled thin-walled cold-formed square steel tubes beams like a spindle.It is of satiation without obvious phenomenon of rheostriction.The members accordingly have good capacity of ductility and energy dissipation.⑵If the width-thickness ratio is smaller or the span-height ratio is smaller,the plumper of the load-displacement hysteretic curves spindle shape is well,and it shows the better capacity of plasticity,then it is provided that it has better properties of resisting the seism.⑶ The different parameters have great influence on the vertical bearing capacity of concrete-filled thin-walled cold-formed square steel tubes beams after analysed its framework curve of load-displacement hysteretic curve.