Plastic design of sustainable steel earthquake resistant structures

Abstract

Earthquakes induce ultimate load conditions in most earthquake resistant structures and often lead to complete failure and disposal. Seismic sustainability is a limit state condition with a view to revival, reuse, and environmental protection. In the present context, sustainable seismic design implies planning for controlled energy dissipation, sequential failures, collapse prevention, construction economy and post-earthquake realignment and repairs. However, regardless of savings and environmental improvements unless an earthquake resistant structure is designed for the purpose, it would be disposable with greater monetary loss and harm to the environment. It has been found that steel mixed multiple seismic systems are well-suited for sustainable seismic design. Mixed multiple structures are combinations of two or more low/controlled damage ductile structures, an articulated gravity frame, a collapse preventive, hybrid, rigid rocking core, and a phantom P-delta system acting together to form a repairable archetype. Each earthquake resistant system is equipped with replaceable energy dissipating and fail-safe devices. Such arrangements call for applications of Plastic Design and Performance Control principles, rather than conventional methods of approach. This in turn calls for development of modern design rules, technologies and details that govern the behavior of such systems equipped with replaceable energy dissipating devices. In the interim several observations that reduce the task of otherwise cumbersome analysis to simple rules of response have been introduced.