دانلود رایگان مقاله انگلیسی ستون های لوله ای فولادی پر شده از بتن مسلح فولادی تحت چرخه محوری و عرضی - اشپرینگر 2018

Abstract

SRCFT columns are formed by inserting a steel section into a concrete-flled steel tube. These types of columns are named steel-reinforced concrete-flled steel tubular (SRCFT) columns. The current study aims at investigating the various types of reinforcing steel section to improve the strength and hysteresis behavior of SRCFT columns under axial and lateral cyclic loading. To attain this objective, a numerical study has been conducted on a series of composite columns. First, FEM procedure has been verifed by the use of available experimental studies. Next, eight composite columns having diferent types of cross sections were analyzed. For comparison purpose, the base model was a CFT column used as a benchmark specimen. Nevertheless, the other specimens were SRCFT types. The results indicate that reinforcement of a CFT column through this method leads to enhancement in load-carrying capacity, enhancement in lateral drift ratio, ductility, preventing of local buckling in steel shell, and enhancement in energy absorption capacity. Under cyclic displacement history, it was observed that the use of cross-shaped reinforcing steel section causes a higher level of energy dissipation and the moment of inertia of the reinforcing steel sections was found to be the most signifcant parameter afecting the hysteresis behavior of SRCFT columns.

Summery and conclusions

In the present study, through fnite-element modeling, the mechanical and hysteretic behavior of steel-reinforced CFT column (SRCFT) was investigated and compared with common CFT columns. The contact stress between steel and concrete causes more axial load strength and larger region of permanent axial strength and the degradation of strength at larger axial displacement. Use of cross steel reinforcement for CFT column caused more energy absorption under cyclic displacement history in comparison with CFT columns. Shear strength of SRCFT column was increased and the degradation of shear strength of specimen occurred at larger lateral drift ratio than CFT column. This performance is related to an increment in total area of steel component, increment of concrete confnement supplied by steel reinforcement, and obtained interruption at cracking of concrete. Thus, SRCFT column can be adopted for many structural engineering applications especially in moment-resistant frames.