Nonlinear Modeling and Seismic Performance Evaluation: A Case Study of a Moment Frame with Equal-Strength Connections

As the design of equal-strength connections allows for controlled yielding in both the end-plates and the beam ends, overstrength of the connections is waived, leading to an optimized material use. This is the design approach that was studied in the current research project, which included monotonic and cyclic tests on full-scale frame specimens. The specimens contained joints in which inelastic deformations were expected in the connections and beams. Based on the monotonic experimental response, the numerical model was calibrated and additional FEAs were performed with the aim to optimize the technical solution. Specifically, an optimization of the shear resistance of the column web panel was necessary to align the technical solution to the design strategy. Based on the experimental and numerical results, nonlinear models of the connections, beam ends, columns and column web panels were subsequently implemented into 4-storey moment frame. The seismic performance of the frame was evaluated by means of Response History Analyses with 7 accelerograms at 3 intensity levels. The paper presents the modeling of the components and discusses the results of the nonlinear dynamic analyses based on indicators such as the: damage state of the frame, interstorey drifts and average M-θ demands on joint components.