Effect of Column-to-Beam Strength Ratio Distribution on the Seismic Behavior of Reinforced Concrete Frame Structures

Abstract

Seismic design codes are the standards that provide resistance for the structures against the potential seismic forces that the structure may face. One of the provisions in the seismic design codes is the strong column-weak beam (SCWB) requirement. It suggests that at that the sum of the flexural strength of the columns at a joint should be greater than those of the beams at the same joint. This requirement aims to prevent column yielding during an earthquake and avoid story mechanisms in moment frames. Although the seismic design codes suggest a minimum column-to-beam strength ratio, previous research has shown that this ratio may not be sufficient to provide desired collapse mechanisms for all conditions. Also, it has been observed that the column-to-beam strength ratio distribution along the height of the frame structures affects the understory and damage distribution. This study investigated the effect of different column-to-beam strength ratio distributions on the drift distribution of the reinforced concrete moment frames. For this purpose, different frames were considered with different numbers of stories and bays. OpenSeesPy framework was used for numerical modeling. To evaluate the seismic response of the model frames, nonlinear time history, and nonlinear static analyses were used. The results showed that the column-to-beam strength ratio distribution significantly affects the distribution of inter-story drift ratios. An effective column-to-beam strength ratio distribution was proposed at the end of the study. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.