Experimental And Discrete Element Method Study On Concrete Shedding Of Hollow Concrete-filled Steel Tube Column

Concrete filled steel tube is a combined member with steel pipe filled withconcrete, which has the characteristics of high bearing capacity, good plasticperformance and the astigmatic property, and so on. Hollow concrete filled steeltube is a kind of special structure of concrete filled steel tube. With higherefficiency and easier to assemble, it has been applied greatly in practicalengineering at present.In the hollow concrete-filled steel tube column, shedding of concrete exertsgreat influence to the bearing capacity of the structure. Whether the concretefalls off or not under different loads is significant in practice. On the one hand,this paper researches the issue of concrete-shedding under the effect of differentload by the test; on the other hand, discrete element method, which widely usedin geotechnical engineering, will be applied to hollow concrete-filled steel tube.It offers an alternative method to solve the problems in this field and to preparefor more in-depth solution for concrete-shedding problems.The test on internal concrete-shedding of hollow concrete filled steel tubehas been done. Through the analysis of concrete-shedding under the effect ofaxial, bias and lateral loads, the result is that under the action of the axis and biasconcrete-shedding won’t occur to the test article, while under the action of lateralload it occurs. Therefore in the axis and bias circumstances, concrete-sheddingcan be over-looked, but under the action of the side load, concrete-shedding hasthe important influence to carrying capacity of member. Through the test wefound that concrete-shedding of specimen will occur after steel tube buckling. Itis suggested that when hollow concrete-filled steel tube column is applied in theproject as the main component, in order to avoid local failure, strengthening ringshould be applied in the place with lateral force. In the discrete element method,by the basic principle of discrete element method the model on steel tube andconcrete-filled steel tube have been built, by which concrete-shedding of hollowconcrete-filled steel tube column was simulated. This process ofconcrete-shedding has been compared with the test, and it is indicated that thediscrete element method can be used to simulate concrete-shedding of hollowconcrete-filled steel tube.The results of the research show that the lateral force has great impact onthe shedding of concrete. Discrete element method can be used as a new methodto simulate the shedding of concrete of hollow concrete-filled steel tube. And it might be tried on similar issues.