Analysis and Study Yields Right Solution

Serving as prime consultant and using new technologies that provide maximum benefit at an affordable cost, we designed the seismic upgrade of this 15-story, 600,000 square- foot steel moment-resisting frame building in downtown Oakland. The building also houses CalTrans emergency operations center and will be a key resource in their post earthquake operations. Four schemes were developed for the project. The original building’s lateral force resisting system is similar to those that were heavily damaged in the 1994 Northridge earthquake. Several factors were critical to the client’s decision on a scheme: cost, construction impact, and staffing disruption to more than 2,000 employees. The chosen solution includes strengthening 60% of the moment-resisting frame connections and installing viscous dampers in 115 bays. Full-scale connection tests and detailed nonlinear finite element analyses confirmed the safety of the connection retrofit design. Nonlinear time history analyses of the retrofitted building model are being used to verify that the design meets the State of California’s needs and design requirements. The advanced analysis and development of four schemes allowed us to find the most cost-effective and least disruptive solution that preserves people’s safety and meets the client’s needs for usability in the event of an earthquake.