Limit state design of resilient earthquake resisting systems

Sustainable Seismic Design (SSD) is the first step toward next-generation earthquake engineering. SSD of Mixed Multiple Seismic Systems (MMSS), where more than one earthquake-resisting structure (ERS) are used, is one of the challenging structural engineering issues. Seismic Sustainability (SS) implies survivability during and after the earthquake, preceded by Post-Earthquake Realignment and Repairs (PERR). Purpose-specific MMSS are ideally suited for SSD. However, contemporary codes address neither sequences nor failure mechanisms of the earthquake-resisting structures of MMSS. The difference between conventional design and SSD is their approach to expected behavior during and after earthquakes. Earthquakes are, natural and dynamic occurrences, whereas PERR is a manual and static process. SSD does not favor unreal detailing nor oversimplifying assumptions; it is a multifaceted effort that involves realistic structural analysis and planned manual operations. In this context, design implies operability with a view to PERR and requires a change from damageability assessment, and Performance-Based Seismic Design (PBSD), to Performance Control (PC) and Reparability Based Design (RBD), including development of new analytic tools and purpose-specific details. The current paper presents graphical solutions and theoretical principles that help achieve practical SSD for MMSS. These new techniques may be utilized for practical reliability, economy, and environmental protection.