Optimization Of Reduced Beam Section Moment Connections
thesisposted on 26.10.2021, 17:23 by Lawal, Morayo Oluwaseun
Reduced beam section (RBS) moment connections also referred to as Dog-bone connections are commonly used in seismic resistant steel moment frames. In RBS connections, the top and bottom flanges of the steel beam are selectively trimmed in the area adjacent to the beam to column connection. This is to ensure that under seismic loading, plastic hinges are formed in the beam not in the column.
The purpose of this study is to optimize the cyclic responses of RBS moment connections including those with sloping beams. Using a response surface method, predictive equations are developed for the response characteristics, such as initial stiffness, plastic strain index, moment capacity, hysteretic energy dissipation, and strength degradation rate. The optimization studies consider objectives leading to higher stiffness, lower plastic strain index, maximum moment capacity, higher hysteresis energy dissipation and lower strength degradation. The optimization results obtained shows that beam slope angle greater than 27.8° will experience fracture, high inelastic demand with higher strength degradation and more intense buckling.