Seismic Performance Assessment and Loss Estimation of Steel Diagrid Structures

Due to their aesthetics and structural advantages, diagrid structures have been used for several mid- to high-rise buildings around the world. However, their seismic performance, collapse fragility, and resilience are yet to be studied. This paper presents a comprehensive investigation into the nonlinear performance of steel diagrid structures using static, time-history dynamic, and incremental dynamic analyses. A framework for seismic performance assessment and loss estimation of steel diagrid buildings is developed. Illustrative and quantitative criteria for performance and damage assessment of diagrid frames are introduced and employed to estimate the seismic loss of archetype diagrid buildings. The diagrids are found to have a substantial collapse capacity and lateral stiffness. Nonetheless, the nonstructural loss due to large maximum absolute floor acceleration experienced by stiff diagrid frames may adversely impact the expected total loss. Due to the shear lag effect, the corner diagonal members are the key elements in their behavior. Further, the effects of building height, diagonal angle, and incomplete diagrid modules on performance and loss are studied.