Research On The Castellated Steel Reinforced High-Strength Concrete Eccentric Compression Columns

Castellated steel is a kind of new component forms by cutting H-beam according to a certain line and then welding together in stagger position, which has been widely used in practical engineering with large rigidity, high load-bearing capacity, economic benefits and some other significant advantages. At present, scholars at home and abroad have done a lot of researches on castellated steel components, however, there are few on applying castellated steel to composite structure. So it is necessary to carry out experimental study on castellated steel reinforced concrete basic building component, analyze its mechanical properties.This paper selects hole shape, expansion ratio and eccentricity as experimental parameters to design seven castellated steel high strength concrete columns to carry out eccentric compression experiment. The paper reveals the failure mechanism under different eccentricity and study the impact of the experimental parameters on the cracking load, ultimate load, stiffness and crack propagation. Experiment shows that:castellated steel high strength concrete columns compared with solid web steel high strength concrete columns under large or small eccentricity, both have the similar failure mechanism. And the former has the higher load-bearing capacity and bending stiffness. And hole shapes have no obvious influences on these either. It is verified whether the section stress meets the flat section assumption and analyzed how the stress around the hole is. Finally,7specimens are numerically simulated with the application of ANSYS finite element software. The simulation results have good agreement with the experiment results, and then extended analysis of the concrete strength, the relative eccentricity and the expansion ratio to the mechanical behavior are taken.The results show that the bearing capacity decrease with the increase of relative eccentricity, and increase with the increase of concrete strength and with the increase of the castellated steel expansion ratio. And compared with solid web steel high strength concrete eccentric compression columns, it has smaller lateral deflection. Finally, preliminary discuss and put forward a method to calculate its ultimate bearing capacity.