UC San Diego

This dissertation advances the analytical and design basis for a proposed prescriptive functional-recovery-based seismic design methodology for buildings comprising unbonded post-tensioned reinforced concrete rocking walls with base friction devices and floor-to-wall force-limiting connections. The research addresses three limitations of current seismic design procedures that present challenges for coordinated functional-recovery-based design: inconsistent procedures for estimating seismic design forces for components in the same seismic load path, limited ability to control structural and nonstructural damage simultaneously, and unintended damage mechanisms at floor-to-wall connections. These challenges are closely connected to higher-mode responses in buildings designed in accordance with current seismic provisions, and prior research has shown that floor-to-wall force-limiting connections distributed over the building height can mitigate these responses. First, measured seismic responses from instrumented buildings in California are used to assess higher-mode effects and ASCE/SEI~7-22 floor-diaphragm design provisions. The results show that the ASCE/SEI~7-22 Section~12.10.1 procedure, which is derived primarily from seismic force-resisting system design forces, can substantially underestimate peak floor accelerations when higher-mode spectral demands are significant. Second, nonlinear numerical earthquake simulations and Monte Carlo uncertainty propagation for reinforced concrete wall buildings show that floor-to-wall force-limiting connections reduce the sensitivity of acceleration and force responses to structural modeling assumptions and reinforcing-steel model uncertainty, supporting the use of computationally efficient models for extensive parametric analyses. Third, the force-limiting connection concept is extended to an earthquake-resilient building system combining rocking walls, base friction devices, and floor-to-wall force-limiting connections. The system is defined, its physical limit states are identified, and four numerical modeling approaches are evaluated against experimental results from related rocking-wall components and building systems. The system uses rocking walls and base friction devices to control first-mode flexure- and rocking-dominant responses and floor-to-wall force-limiting connections to control higher-mode shear-dominant force and acceleration responses. Fourth, the proposed buildings are compared with special reinforced concrete wall buildings having conventional connections; response control through the wall base moment strength and the connection design limiting-force level is evaluated; and three structural-dynamics-based formulations for estimating distributions of connection design limiting forces over the building height are proposed and evaluated. Finally, unified seismic design forces are formulated by separating first-mode and higher-mode contributions and applying distinct connection and seismic force-resisting system response modification factors. A parametric analysis framework is defined to relate building characteristics, earthquake intensity levels, response modification factors, and component-level design variables to seismic performance metrics and, through a subsequent probabilistic damage and recovery assessment, to probabilistic functional-recovery-based performance metrics. A design-consistent nonlinear numerical earthquake simulation workflow was developed for building archetypes defined from metadata for instrumented earthquake-resistant buildings in California. Far-field ground motions were selected and scaled to match the target design spectrum and spectral variability and were subsequently scaled to the other considered earthquake intensity levels. The workflow was used to execute the full 16-archetype simulation matrix, while selected response statistics for one 12-story office archetype are presented. These components are organized into a proposed prescriptive functional-recovery-based seismic design framework intended to connect owner-defined probabilistic functional-recovery-based target performance limits to the selection of design variables and the computation of unified seismic design forces. The detailed analysis of the full simulation database, the probabilistic functional-recovery assessment, and the functional-recovery-based design maps remain ongoing; therefore, the dissertation establishes the basis for the proposed methodology but does not complete its prescriptive implementation.