Optimizing the Design of Tall Buildings Using the Principle of Virtual Work: The Eff ect of Semi Rigid Connections

• Published in: International journal of steel structures pp. 1 - 21
• Main Authors: Alex Elvin, Johnnie Strydom
• Format: Journal Article
• Language: English
• Published: 한국강구조학회 01.02.2021
• Subjects: 토목공학
• ISSN: 1598-2351; 2093-6311

The Virtual Work Optimization Method (VWOM) is used to optimize tall buildings with semi rigid connections. The VWOM is an automated method that minimizes the mass of a structure with a given geometry, defl ection criteria and load cases, while adhering to building code requirements. Members are selected from a user defi ned database to meet strength and stiff ness criteria. The rotational stiff ness of connections can be specifi ed and varied, from rigid to pinned. The method is explained using an example of a two storey one bay steel frame with six members. Four case studies are presented: (i) a six storey two bay frame, (ii) a ten storey one bay steel building, (iii) a fi fteen storey three bay steel frame and (iv) a twenty four storey three bay building. The examples are compared to results found in the literature. Structures were optimized for a range of connection rotational stiff nesses. The VWOM obtained results up to 44.6% lighter than published work. Optimized results showed that in most cases the semi rigid connection produced the same results as the rigid connections. This is due to the rapid plateauing of the optimized mass as the connection stiff ness increases. Thus, the typical defi nition of semi rigid and rigid rotational stiff nesses (for example Eurocode 3) are both found on this plateau. If some members are lightly loaded, broad semi rigid and rigid bands can be produced. The eff ect in these cases is that structures with rigid connections are lighter than those with semi rigid connections as no compensation in the member stiff ness is required to meet defl ection criteria. KCI Citation Count: 0