• International Journal of High-Rise Buildings
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• v.5 no.4
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• pp.263-270
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• 2016

In this paper, the stability requirements for diagrid and mega braced structures are examined. The role of the secondary bracing system for the stability of a diagrid structure is discussed. A simple procedure is proposed for the design of the secondary bracing system when it is required. As a case study, the design of the Hearst Tower diagrid and its secondary bracing system are presented.

• International Journal of High-Rise Buildings
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• v.5 no.4
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• pp.319-326
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• 2016

The ingenuity of structural engineers in the field of tall and super-tall buildings has led to some of the most remarkable inventions. During this evolution of structural engineering concepts in the last 100 years, the technical challenges that engineers encountered were extraordinary and the advances were unprecedented. However, as the accomplishments of structural engineers are progressing, the desire for taller and safer structures is also increasing. The diagrid structural system is part of this evolving process as it develops a new paradigm for tall building design combining engineering efficiency and new architectural expression. The first appearances of this type of tall buildings have already been constructed and the interest of both engineering and architectural communities is growing mainly due to the many advantages compared to other structural systems. This paper presents a simple approach on optimizing member sizes for the diagonals of steel diagrid tall buildings. The optimizing method is based on minimizing the volume of the diagonal elements of a diagrid structure. The constraints are coming from the stiffness-based design, limiting the tip deflection of the building to widely accepted regulative limits. In addition, the current paper attempts to open the discussion on the important topic of optimization and robustness for tall buildings and also studies the future of the diagrid structural system.