Author(s)

M. DAN & M. KOHIYAMA

Abstract

This paper proposes a simultaneous optimal design method of asymmetric large-scale space frames with tuned mass dampers (TMDs). The objective function is defined by the maximum absolute accel- eration response of the structure to input ground motions of sine waves. Sine waves of periods with the five natural periods having large modal participation factors of the structure are input, and the maximum responses are calculated by time–history response analysis to evaluate the objective function. The shape of the space frame, i.e. nodal coordinates of the space frame’s joints, is described by a Bézier surface to reduce the number of design variables. The change from the initial values of the nodal coordinates is constrained to preserve the initial design shape, which is provided by an architect. The method employs a genetic algorithm in optimization. In addition, a case study is conducted for an asymmetric steel space frame of a vault-like shape. The results confirm the reduction of maximum absolute acceleration responses in the optimal shapes not only to the five sine waves but also to four scaled ground motion records. Moreover, the presence of TMDs enables the reduction of the peak response value and maintains similarity to the initial shape.

Keywords

architectural design, Bézier surface, earthquake engineering, genetic algorithm, optimiza- tion, seismic control, structural engineering, structural shape, space frame, tuned mass damper