Abstract

The dynamic loads acting on concrete-filled steel tubular members under axial impacts by rigid bodies were studied herein by FEM. The whole impact process was simulated and the time history of the impact load was obtained. The effects of eight factors on the axial impact load were studied; these factors were the impact speed, mass ratio, axial pressure ratio, steel ratio, slenderness ratio, concrete strength, impact position, and boundary conditions. Besides this, the effects of concrete creep on the impact load were also considered by changing the material parameters of the concrete. The results show that axial impact load changes with time as a triangle. The peak value of impact load increases and the impact resistance improves with the growth of the axial pressure ratio, steel ratio, slenderness ratio, and concrete strength after creep occurs. As the eccentricity of the axial impact acting on a concrete-filled steel tubular member increases, the peak value of the impact load decreases. The enhancement of constraints at both ends of the member can improve the impact resistance. The creep reduction coefficients for the peak axial impact load of a concrete-filled steel tubular member under axial compression and considering the creep effect over 6 months and 30 years are 0.60 and 0.55, respectively. A calculation formula for the peak value of impact load was suggested based on the existing formula, and its accuracy was proved by finite element calculation in this study.

Highlights

  • A concrete-filled steel tubular member is a combined member which is produced by filling a thin-walled steel tube with concrete

  • Under the action of axial compression at the service stage, the core concrete will suffer creep as time goes on; this will cause the cooperative work of the core concrete and steel tube to be broken and cause the redistribution of their internal forces

  • This paper explains a finite element model established in ABAQUS software to simulate the whole whole process when a concrete-filled steel tubular member with creep effect bears axial impact

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Summary

Introduction

A concrete-filled steel tubular member is a combined member which is produced by filling a thin-walled steel tube with concrete. Sapountzakis [3,4,5] analyzed the dynamic responses of a reinforced concrete beam and slab structure with creep effects by considering the internal force and deformation of slabs and the axial. This paper explains a finite element model established in ABAQUS software to simulate the whole whole process when a concrete-filled steel tubular member with creep effect bears axial impact. Compression and considering the creep effect is suggested based on the existing formula This will provide a theoretical basis for the impact resistance design of concrete-filled steel tubular provide a theoretical basis for the impact resistance design of concrete-filled steel tubular members

The detailed parameters of the basic specimen as shown inimpact
Material Properties
Months
Finite Element Model
Results and Discussion
Impact
Axial Pressure Ratio Effect on Impact Load
Axial pressure
Steel Ratio Effect on Impact Load
Slenderness
Slenderness Ratio Effect on Impact Load
Concrete
Eccentricity of Axial Impact Effect on Impact Load
Boundary
Creep Reduction Coefficient on Peak Impact Load
Peak Impact Load Calculation Formula Considering Creep
Conclusions
Full Text
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