Sustainable and Cost-Efficient Design Optimization of Rectangular and Circular-Sectioned Reinforced Concrete Columns Considering Slenderness and Eccentricity

In buildings, the transfer of external and internal loads starting from the roof and the top floor should gradually be carried towards the lower floors through column elements in a safe way and eventually transmitted to the foundation system of the building and then to the ground. Thus, the reinforced concrete columns are crucial structural elements that provide essential load transfer between stories of the buildings and resist horizontal loads such as earthquakes. The purpose of this study is to examine the effect of slenderness and eccentricity on achieving the most sustainable and most cost-effective design of rectangular and circular sectioned reinforced concrete columns. Slenderness is a crucial concept for bearing structural elements in pressure. Besides, the eccentricity is a frequently encountered term in practice. Unlike prior researches, this study takes the effect of slenderness, eccentricity, and cross-sectional geometry into account as well as the discrete design variables and codes of practice. The main goal of the optimization procedure is to generate a sustainable and cost-efficient reinforced concrete column design. The characteristic strength of the concrete, sizes of cross-sections, cross-sectional area of longitudinal and confinement rebars and their numbers are considered as discrete design variables in optimal design problem. The Turkish Requirements for Design and Construction of Reinforced Concrete Structures (TS500) and Turkish Building Earthquake Code (TBEC), which are complement each other, are used to determine realistic design constraints of design optimization problem. Thus, two different rectangular and circular sectioned reinforced concrete columns, which have three lengths, are sustainably and cost-efficiently optimized under three different load cases considering three various eccentricities via grey wolf optimizer. Finally, the attained 108 alternative optimum designs are evaluated in terms of sustainability (CO2 emissions) and cost-efficiency as separate objective functions. Consequently, the innovative attractive design solutions are accomplished such as external loads are less effect than height of the column on the optimal design of reinforced concrete columns.