Tremblay et al. 2008
A Viscously Damped Controlled Seismic Rocking system is proposed and evaluated. A parametric study was carried out to evaluate the seismic performance of the VDCSR system for 2, 4, and 6-story building applications. Also a design model is created and compared to experimental results.
System Concept
The VDCSR system is design to enhance the seismic performance and reduce force demand of the building structure. Column uplift and rocking is allowed over the foundation. Embedded dampers or damper mounted beside the columns control the uplift force created by the overturning moments. The system is applicable for new designs and seismic retrofit projects.
Analytical Study, Results, and Discussion
An analytical model was created using SAP2000 and used to predict the seismic response of the system. A half-scale model of a 2-story rocking chevron braced steel frame was tested using a multi-cellular shake table. A nonlinear time-history dynamic analysis of both the prototype and model structures was conducted to validate the assumptions made in design of the test model. The test model was subjected to ground motion records based on three locations exhibiting three different seismic settings. These locations included Montreal QC, Vancouver, BC and Los Angeles, CA. The frame was also subjected to harmonic signals with various amplitudes and frequencies.
The analytical testing showed that the system has the potential to reduce column uplift loads compared to conventional braced steel frames. All of the structures were able to sustain design ground motion demand without structural damage at the peak later displacements. Also the viscous damper properties were confirmed through dynamic testing.
Reference
Tremblay, R., Poirier, L.-P., Bouaanani, N., Leclerc, M., Rene, V., Fronteddu, L., and Rivest, S. (2008). “Innovative Viciously Damped Rocking Braced Steel Frames,” Proceedings of the 14th World Conference on Earthquake Engineering 2008, Beijing, China, October 12-17.