Investigating the buckling behavior of CFT columns with tensile reinforcing bars at the base of the column

Concrete-filled steel columns (CFT), comprising concrete as the inner core and steel as the outer wall, are increasingly utilized in civil engineering due to the effective synergy between these materials in enhancing strength and reducing buckling. The encasement of concrete within a steel pipe significantly influences the structural behavior of these columns. This research focuses on the buckling analysis of CFT columns to determine the maximum load they can withstand before failure. Finite element modeling was conducted using ANSYS ۱۹ software, simulating various column designs with square geometry, both with and without reinforcing bars, across different lengths and diameters under identical boundary conditions. The thickness of the steel pipe was varied from ۳ to ۹ mm, while column lengths ranged from ۳۰۰۰ to ۵۰۰۰ mm to assess the impact of these changes on buckling behavior. The results indicate that increasing the column length decreases the critical load, leading to premature buckling. Conversely, the buckling resistance of the column improves with greater length, additional reinforcing bars, and increased steel tube thickness. These findings align with Euler's theory of critical buckling loads, confirming the influence of various factors such as rebar diameter, steel tube thickness, and column length on critical load values.

کلیدواژه ها:

Buckling behavior ، CFT columns ، tensile reinforcing bars ، Euler critical load