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Go to Editorial ManagerThis experimental investigation evaluates the structural behavior of reinforced concrete slab-column connections incorporating columns with square and circular cross-sectional geometries under gravity and lateral cyclic loading. Four interior slab-column specimens were designed, fabricated, and tested, with identical slab dimensions of 1050×1050×80 mm and a column height of 500 mm. The circular columns were intended to have an equivalent second moment of inertia to the square column, ensuring a fair comparison of geometric effects. One specimen identified as SC-G, incorporating a square column, was tested under a progressively increasing vertical load to determine its maximum gravity load-bearing capacity. The remaining three specimens SC-2 with a square tied column, SC-9 with a circular spirally-reinforced column, and SC-10 with a circular column incorporating a column capital were tested under a constant gravity load equivalent to 60% of SC-G’s ultimate capacity (75 kN), combined with a lateral displacement protocol conforming to ACI 374 guidelines. Results indicated that the shape of the column (circular) and reinforcement (spiral) in SC-9 produces a comparatively higher ultimate load, stiffness, and ductility than SC-2 of the square column and tied reinforcement. The ultimate lateral load increase was +13.3%, -26.1%. Circular spiral columns with column capital in slab-column connections led to a noticeable rise in ultimate lateral load by about +62%, -80%. It was also shown that incorporating a column capital in SC-10 significantly enhanced the punching shear resistance and energy dissipation capacity. Circular columns demonstrated more stable hysteretic behavior and improved ductility compared to the square column specimen.
The aim of this work is to investigate the effect of soil corrosion on the critical buckling load of circular columns made of 2014-T4 aluminum alloy. In this work, 24 specimens were used and buried in the soil for 120 days. The samples divided into two groups (12 columns with corrosion before shot penning (SP) and ultrasonic impact treatment (UIT), and 12 columns with corrosion after combined surface treatments (SP+UIT)). The experimental1results revealed1that the corrosion negatively1affects the mechanical properties1of the material, and the1reduction percentage (R%) for1ultimate tensile strength (UTS) and1yield strength (YS) was (1.95% and 4.57%) respectively. After combined surface treatments (SP+UIT) for the corroded columns, the ultimate1tensile strength (UTS) and yield1strength (YS) were improved with (2.42%, and 2.87%) respectively. Perry-Robertson, Rankine, and ANSYS were used to estimate the critical buckling load (Pcr) and compare it with the experimental results. Rankine and Perry's formulas have been achieved a good agreement with the experimental without and with (1.5) factor of safety respectively. While ANSYS gave satisfactory prediction with a safety factor of (2.2, and 2.7) and (1.9, and 2.7) for long and intermediate columns before and after (SP+UIP) respectively.