A New Approach to Determine the Flexural Stiffness for Reinforced Concrete Columns According to Non-Linear Behaviour

Accurate calculation of the effective stiffness of RC load-bearing elements has always been an important research topic, as it allows reliable estimation of the capacity of buildings under seismic loads. Although the effective stiffness of the cracked section in load-bearing elements is not constant, it varies depending on the design parameters that affect the non-linear behaviour of the elements. A more secure and simpler prediction equation for the stiffness coefficient of sections has been developed by considering important design parameters in the RC columns designed with different geometries. The stiffness coefficient of columns; relationships specified in different seismic codes; nonlinear analyses of proposed equations; and parametric studies were investigated. By comparing the proposed predictions for the stiffness coefficient with other prediction equations, the results of the numerical analysis were used to verify the predictions. Since different section geometry and important design parameters influencing the non-linear behaviour of sections are considered in the equations proposed for the column models, quite accurate and consistent results are obtained for the stiffness coefficient of the columns, as can be seen from the numerical analysis results.