To investigate the progressive collapse behavior of steel moment frame with damper, a new-type mild damper consisting of cruciform steel plates is designed. The mechanical properties of the damper are validated through the theoretical calculation, previous tests and numerical analysis, respectively while the accuracy of model structure is validated with different FEM software. Therewith, the studies on the progressive collapse and seismic design of an in-plane model structure with new-type dampers are conducted. It is found that the progressive collapse resisting capacity of the structure is improved resorting to the damper. Better catenary action exists in the in-plane model structure with damper while the anti-seismic ability of structure becomes poor. Considering the spatial effect of structure, the optimization of damper arrangement is conducted for the seismic design. The results demonstrate that the dual action of damper, namely for the progressive collapse and seismic designs, could be guaranteed simultaneously in three-dimensional (3-D) structure. The analysis results in this paper provide a reference for the unified design of resisting the earthquake and vertical progressive collapse.
