A parametric investigation on gate braced frames

This study reported the results of a parametric investigation on the nonlinear behavior of multi-storey reinforced concrete buildings before and after upgraded with gate bracing systems having different eccentricity parameters and configurations. Gate bracing system contains of six members that are symmetrical, and in each side, three members connected to the certain point in the frame bay were employed. Two of them were non-straight diagonal elements while the third one was stretched on one side and connected to the edge of the frame. The case study structures with 2, 4, 6, and 8 storey had the same floor plan (3x3 bays) having the same bay length 5.5 m and storey height 3.3 m for all cases. In the current study, four different eccentricity parameters ranged from 0.2 to 0.8 and eight different configurations of gate bracing over the frame height were introduced. Each bracing part was chosen as circular hollow section with the fixed diameter and wall thickness. A total of 132 frame models (covering 4 without bracing and 128 with gate bracing) were subjected to the nonlinear static pushover analysis. The comparative analysis showed that the lateral load carry capacity of the structure was very close to existing building in 2 storey building in configurations that had no brace in ground floor, but in other cases we noted that decreasing the eccentricity from 0.8 to 0.2 dramatically increased the seismic capacity of all case studied structures.