Seismic performance of a chevron-braced frame with an arc-shaped energy-dissipating structure

The steel chevron-braced frame generates large unbalance forces and vertical deformation at the intersection of the brace and beam; in addition, the brace experiences out-of-plane instability under seismic loading. To reduce the vertical deformation, unbalanced forces and out-of-plane instability, a chevron-braced frame with an arc-shaped energy-dissipating structure is proposed in this study. The seismic performance of the proposed structure was evaluated by way of finite-element analysis. The results showed that the proposed structure exhibits a higher, consistent load capacity under cyclic loadings, and the load capacity does not change abruptly. In addition, the hysteresis curve is fuller and no ‘pinch shrinkage’ is observed. The energy dissipation coefficient is larger, and the load-bearing capacity degradation curve varies less. Moreover, the vertical displacement at the brace–beam intersection is smaller, and no out-of-plane instability occurs in the brace. Deformation occurs mainly in the arc-shaped energy-dissipating structure, as well as at the top and bottom of the column. The stress in the frame of the proposed structure is lower, particularly when the stress in the steel beams is significantly reduced. The spacing, thickness and height of the rib plate of the arc-shaped energy-dissipating structure impose considerable effects on the seismic performance, whereas the other parameters exert only small effects.