A research team from Case Western Reserve University, the University at Buffalo (UB), and California Polytechnic State University (Cal Poly) will investigate a methodology for rehabilitation of seismically substandard buildings through implementation of stiff elastic rocking cores. The stiff rocking core (SRC) has the potential to redistribute seismic forces along the core height to create a more uniform building drift distribution. Concentrated ductility demands on a single story can develop due to a number of reasons that may or may not be foreseeable in initial design. For buildings that do not have adequate seismic ductility and/or strength, added energy dissipating devices, such as steel yielding devices or viscous dampers, can be implemented between the SRC and the existing framing to reduce these demands. Implementation of the elastic SRC adds the potential for re-centering of the building and is expected to be a cost-effective and an architecturally flexible rehabilitation technique. This research will investigate the behavior of the SRC and its interaction with existing framing that includes low-rise and mid-rise, braced frame and moment frame buildings to understand the key parameters for effective rehabilitative design of substandard frames. Advanced analytical studies will be performed to investigate the behavior and assess the effectiveness of the SRC for a range of parameters. A key component of the research includes near full-scale experimental hybrid testing of a three-story frame at the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) facility at the UB. The hybrid testing technique will allow for computational modeling of the existing substandard framing and experimental testing of the SRC with added passive energy dissipation. The testing is critical for understanding the interaction between the existing framing and SRC and for verifying implementation issues at or near full-scale. Data from this project will be archived and made available to the public through the NEES Project Warehouse data repository at www.nees.org.
This research will generate key knowledge needed to implement this rehabilitation technique, which is both economical and sustainable, for substandard building structures in moderate and high seismic regions. The analytical and experimental results and design guidelines developed will be a valuable resource for researchers and practitioners in the seismic design community. Through technology transfer via the Project Advisory Committee, the research outcomes will have an immediate impact on practice. Through collaboration with the Cal Poly Multicultural Engineering Program, the project will engage students from underrepresented groups to give them experience with structural engineering research and laboratory experimentation, ultimately helping to promote diversity in engineering and science and developing the next generation of engineers. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).