A study on seismic behaviour of mega braced RC frames

This study investigates the seismic response of reinforced concrete (RC) frame structures before and after applying mega bracing system. For this, an eight story and four bay RC frame (bare frame) was used. The case studied frame had an inter-story height of 3.5 m for all floors and a span length of 6 m. In braced frame cases, five different bracing configurations in which bracing were installed across four bays of the structure were utilized. The diagonal brace members were selected as circular hollow section (CHS). Five different sizes of CHSs with an outer diameter ranged from 80 to 180 mm and two different wall thicknesses (4 and 6 mm) were used. Thus, a total of 51 different cases were considered in this study. Nonlinear pushover analysis was conducted to assess the structural performance of different frames. The capacity curve in terms of base shear coefficient vs. roof drift, displacement distribution at mechanism, maximum base shear, initial stiffness, plastification were evaluated to compare the seismic response of the bare and braced frames. The results indicated that the brace layout and section properties used in the application of mega bracing were very effective in the response of the structure under lateral loading.