Performance-Based Seismic Design

Presented by Joe Ferzli, Cary Kopczynski & Company; and Mark Whiteley and Cary S. Kopczynski, Cary Kopczynski & Company

Recent advances to both the body of knowledge and the computing power available to structural engineers have created opportunities for tall buildings to be designed and analyzed with a better understanding of the structure’s seismic response than ever before. This has ushered in a new age of efficient tall buildings designed using a performance-based design (PBD) philosophy. This presentation will discuss in detail case studies of tall building projects, under construction or completed on the West Coast that utilized performance-based design principles and nonlinear modeling. Each project will be used to highlight a unique aspect of the design process and give the audience a glimpse into what is possible using state-of-the-art seismic analyses and underline emerging topics. Design of slender shear wall cores and eccentric cores will be addressed. Comparative studies showing the difference in geometry and reinforcement using code-prescribed procedures and performance-based methodologies will be presented. The mechanism of seismic energy dissipation through ductility will be illustrated. Ductile core approach can result in smaller cores with less overall force in the system, creating value through material and labor savings. Additionally, special attention will be given on how recent research on high-performance fiber reinforced concrete (HPFRC) has been incorporated into the design of tall buildings through the use of performance-based approach and nonlinear modeling. In addition, the practical implementation of these innovative designs will be discussed from a constructability perspective. Parametric studies of various modeling assumptions will be presented to show the importance and sensitivity of each selection. One of the key goals of this presentation is to increase awareness of the importance of PBD and ductility in the design of tall buildings in high seismic regions.