Numerical Study on the Impact of Out-of-Plane Eccentricity on Lateral Behavior of Concentrically Braced Frames

This study presents a numerical evaluation of lateral performance of Concentrically Braced Frames (CBFs), assembled with unwanted out-of-plane eccentricity at the connection of their braces. Nonlinear analyses are performed on one-bay, two-story steel single diagonal CBF. Static pushover and cyclic analyses are carried out to show the impact of such out-of-plane eccentricity. Finite element modeling of the whole members, validated with experimental results, is taken into account. Fine meshes are used in regions where inelastic deformations are expected. The results indicate that constructional defect due to out-of-plane eccentricity decreases the maximum strength of the frame compared to a perfect model. Applying cyclic loads to the eccentric model leads to a decrease in energy dissipation. Adding web stiffeners to column of eccentric models is effective to compensate the strength loss. Finally based on obtained results, such unwanted out-of-plane eccentricity has negative effects on lateral behavior depending on the geometric properties of the frame and bracing configuration.