The Experimental Research On Concrete-Filled Steel Tube Under Lateral Impact Load

Concrete-filled steel tube is formed by concrete filled in the steel tube. With the interaction between steel tube and concrete, it brings the advantages of these two kinds of materials into full play, not only improves the plasticity highly and toughness of concrete, but also avoids local flection of steel tube. So the concrete-filled steel tube is characterized by high bearing capacity, fine plasticity and toughness, excellent economic benefits and convenient construction.In recent years, the dynamic responses of structures under impact load ,as a hot topic, have caused great concern in the civilengineering field. In this paper, the detailed dynamic response and damage feature of the concrete-filled steel tube under lateral impact has been studied with experimental investigation. At the same time, the appropriate additional and extensive analysis with FEM software ANSYS/LS-DYNA on the model has been performed.On experiment part, two kinds of support concrete-filled steel tubes are impacted under different energy. The time-history curves of impact loads and accelerations, displacement ,local deformation and strain have been obtained through the test. The paper made an analysis of relations between impact load and energy, plastic hinge, energy dissipation, failure mode and resistance to impact, etc. Meantime, in order to compare with the concrete-filled steel tube, a few hollow steel tubes have been tested under impact. In the end, the research of concrete-filled steel tubes under static load have been done to provide credible data for experiment and FEM studies, and the P- Δ curves and P- ε curves have been obtained.Based on the above experimental investigation, the simply supported concrete-filled steel tube under impact has beenanalyzed further with ANSYS/LS-DYNA program. Some phenomena and results that cannot be observed and measured in the dynamic experiment have been achieved, including the time-history curves of displacement and velocity, stress state and strain state, etc. and their laws have been analyzed. In order to approach strength state of real project, the concrete-filled steel tubes with axial pressure under lateral impact have been analyzed with the FEM software; the influence of the axial pressure on impact property has been observed and the results with axial pressure is compared with the ones without.This subject has provided the credible reference and the analysis method for further research, and at the same time offered reference for engineer to design relevant structures.