Shape optimization of braced frames for tall timber buildings: Influence of semi-rigid connections on design and optimization process

• Published in: Engineering structures Vol. 216; p. 110692
• Main Authors: Mam, Koliann, Douthe, Cyril, Le Roy, Robert, Consigny, François
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2020; Elsevier BV; Elsevier
• Subjects: Axial loads; Bearing strength; Carrying capacity; Civil Engineering; Construction durable; Design; Design optimization; Eco-conception; Engineering Sciences; Glulam; High rise buildings; High-rise building; Lateral loads; Load carrying capacity; Optimality criteria; Optimization; Reinforcement (structures); Semi-rigid connection; Semi-rigid connections; Shape optimization; Stiffness; Structural behavior; Structural optimization; Tall buildings; Timber; Timber (structural); Topology; Wind loads; Wooden structures; Semi-rigid connection; Structural optimization; Timber; High-rise building; Optimality criteria
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2020.110692

•A design technique of an optimal braced frame with dowel-type connections is presented.•Connections contributes greatly to the overall stiffness of timber structures.•Connection stiffness may influence the optimal geometry of a braced frame system. With the recent development of timber as a viable structural material for high-rise structures, glulam braced frames have been recently introduced in lateral load-resisting systems of timber buildings. Based on a simple shape optimization problem of a braced frame, this paper explores one of the specificities of timber structures: the influence of semi-rigid connections on their overall structural behavior and design. Dowel-type connections are first studied to obtain a simplified relation between joint stiffness and axial load-carrying capacity. Then, the established local behavior law is introduced in the shape optimization process and design of a discrete braced frame subject to lateral drift constraint under wind load. The problem is solved by a COBYLA optimization method, combined with Optimality Criteria (OC) member sizing techniques. Solutions are then evaluated and compared with classical steel/concrete design. The semi-rigid behavior of connections finally leads to a significant increase in the volume of timber but also affects the optimal shape and topology of the X-braced frame compared with classical results.