Abstract: This project involves an out-of-code high-rise long-span complex steel frame structure. It is characterized by a local upper-suspended and lower-bracing structural system， and incorporates a damping technology that integrates a toggle-brace displacement amplification mechanism with a friction-type displacement damper. This paper presents the selection of the load-bearing and lateral resistance systems for the structure， with a focus on analyzing the stress and deformation characteristics of this special structural type， the design of the suspension system， damper damping technology， as well as stress analysis and control of long-span truss floor slabs. Analyses for progressive collapse resistance and comfort of the long-span truss were carried out， along with a construction simulation analysis of the entire structure. The structural system also includes different types of force-transfer components such as landing columns， transfer columns， and suspended columns. It belongs to a special type of high-rise building that is not specified in current codes and has multi-directional force transfer paths. Corresponding performance-based design objectives have been formulated， and stress ratio control standards for steel members under different performance levels have been proposed. Through comprehensive theoretical calculations and appropriate structural measures， the structural system can be ensured to be reasonable and safe.