The Analysis On The Dynamic Performance And The Dynamic Shear Force Capacity Of CFDST Columns Under Vehide Impact

With the foundation of the traditional Concrete-filled steel tubular structure, Concrete-Filled Double Skin Steel Tubes (CFDST) as a new type of steel-concrete composite structure not only have the advantages of the traditional steel concrete structures, but also carried out cross-section and great bending stiffness,compared to Concrete-filled steel tubular (CFST). This structure is widely used in high-rise buildings, bridges and power facilities. During the whole life cycle, concrete-filled double skin steel tubes may inevitably suffer from various impact loads. In current the research about steel-concrete composite structure focuses on the performance about axial compression, bias, bending, and low cyclic loads, but the research about it under lateral impact is equally import. In this paper, the behavior of concrete-filled double skin steel tubes (CFDST) with fixed boundary condition in high-rise buildings was analyzed by Experimental and Theoretical studies. The dynamic shear force capacity corresponding to performance levels and the dynamic shear force demand on CFDST column were analyzed. The main contents are as follows.Firstly, experimental work of CFDST column under transverse impact load was done with the drop hammer rig. The main parameters of the specimens include the impact height, the imposed load and the appearance. Hollow steel tubes were also tested under the same condition. Failure modes, impact force curves, mid-span deflection curves and strain curves were recorded in the tests. The test results showed that CFST beams have ductile failure modes and good impact resistance.Then a finite element analysis (FEA) model was established to predict the impact behaviour of CFDST members, in which the strain rate effects of the materials were considered. The effect of axial load and crack of steel tube were also simulated in the FEA model. And analysis the effect of dynamic shear force capacity corresponding to the performance levels under the different degree of the hollow.Thirdly, a finite element analysis (FEA) model was established to predict the dynamic shear force capacity corresponding to performance levels of CFDST column and the dynamic shear force demand on CFDST column.The dynamic shear force capacity is less than the dynamic force demond for the cases in which damage is observed.This serves as an additional validation for the proposed methodology.The proposed proformance is able to estimate the dynamic shear force capacity of and demand on the CFDST column corresponding to different performance levels.The change in dynamic shear forve and loading is also observed.A corresponding dynamic shear force capacity and demand can be evaluated the safety of the CFDST column during an impact event.Last, a procedure to estimate the different dynamic shear force capacities corresponding to performance levels is established.