Analysis and Comparison of Connections in Steel Structures

The topic of connections is often given only limited attention in structural analysis and design of buildings, despite the fact that they can play a critical role in the structure. It is customary practice in the U.S. for the structural engineer to design the structural members, but leave the connection details to the steel fabricator. While this practice is more efficient and pragmatic in some instances, it is also necessary for structural engineers to have a good knowledge of connection behavior, especially when dealing with newer or atypical connections. Both the theoretical modeling of connections and the physical geometry and components of connections are considered in this thesis. For the theoretical modeling of connections, the concept of semi-rigid connections as an alternative to the conventional idealizations of perfectly pinned or rigid connections will be addressed. Included will be methods to model and design semi-rigid connection behavior within frames. The effects of connection behavior on frames will also be considered. With regard to the physical components of connections, an overview of types of fasteners and joints will be presented, including types and methods of installing bolts and welds, shop-welded, field-bolted column trees, and comparisons between these options. A final section presents options for connections between hollow structural sections of both circular and rectangular cross sections. Finally, the topics covered for connections will be applied to the design project for the MIT class 1.562 as part of the MEng program in high performance structures. Thesis Supervisor: Jerome J. Connor Title: Professor of Civil and Environmental Engineering