The Numerical Experiment Of Concrete-filled Rectangular Steel Tubular Columns

In recent 20 years, as the architectural material and technical developments, the concrete-filled steel structures has gradually been applied in the architectural structure especially in the high buildings. According to different sections, concrete-filled steel tubular can be classified as concrete-filled circular, square, rectangle and polygon steel tubular etc. Compared with the circular concrete-filled steel tubular, concrete-filled rectangular steel tubular have some advantages: easier to connect with beams; better stability; and the low cost of fire prevention etc.When the concrete-filled rectangular steel tubular columns are compressed the interactions between steel pipe and concrete is very complicatedly, therefore, in the loading process, the stress and crack complexion of steel pipe and concretes can't be attained by calculation or analysis. Because the steel pipe can't be broken to observe the internal circumstance during the experiments, the results only are observe by incising the pipes after the experiments. In each stadge of loading process, the crack and interaction reasons of steel pipe and concrete respectively between steel pipe and concrete can't be confirmed .In this literary, the assumption is used that the thin view unit material strength with Weibull distribution is used to explain reason of the submicroscopic non- linearity of quasi-brittle material is the thin view non- homogenization .By using the software which is developed on this theory, the experiment of concrete-filled rectangular steel tubular columns under axial compression is simulated. Using the software incising the concrete-filled rectangular steel tubular columns are observed, also the interaction between steel pipe and concrete, and the crack and stress circumstance of steel pipe and concrete in each step of loading process are analyzed . The research results indicate that: (1) The concrete-filled rectangular steel tubular columns have good abilities to resist loadings and transmutation.(2) The process of steel pipe peeling off the concrete columns appear in the first declining phase in the N -εcurve (3) When the entering the mild phase, the ultimate bearing capacity of the component is depended on the compress strength of steel pipe.Using the model parameters which are suit to columns under axial compression numerical simulative experiment, the numerical experiment of a kind of concrete-filled rectangular steel tubular columns under non-axial compression which haven't been studied is made in this literary. And also the crack forms, compress strength, process, behaviors of concrete-filled rectangular steel tubular columns are analyzed detailedly. (1)At the beginning of loading, the major principal stress centralize in a triangle area under the lap.(2) The limit load of this case happens when the steel pipe is mangled in the lap area.(3)Two cracks appear in the loading process.(4) The deformation of column under this kind of non-axial compression is depended on the eccentric ratio. Because there is little research about concrete-filled rectangular steel tubular columns under non-axial compression, the numerical experiment is hoped to replace the true experiment partially or wholly, and put forward some references to the research on concrete-filled rectangular steel tubular under non-axial compression.