Performance-Based Seismic Design (PBSD) of reinforced concrete buildings has rapidly become a widely used alternative to the prescriptive requirements of building code requirements for seismic design. The use of PBSD for new construction is expanding, as evidenced by the design guidelines that are available and the stock of building projects completed using this approach. In support of this, the mission of ACI Committee 374, Performance-Based Seismic Design of Concrete Buildings, is to “Develop and report information on performance-based seismic analysis and design of concrete buildings.” During the ACI Concrete Convention, October 15-19, 2017, in Anaheim, CA, Committee 374 sponsored three technical sessions titled “Performance-Based Seismic Design of Concrete Buildings: State of the Practice.” The sessions presented the state of practice for the PBSD of reinforced concrete buildings. These presentations brought together the implementation of PBSD through state-of-the-art project examples, analysis observations, design guidelines, and research that supports PBSD. This special publication reflects the presentations in Anaheim. Consistent with the presentation order at the special sessions in Anaheim, the papers in this special publication are ordered in four broad categories: state-of-the-art project examples (papers 1-5), lateral system demands (papers 6-8), design guidelines (papers 9-10), and research and observed behavior (papers 11-13). On behalf of Committee 374, we wish to thank each of the authors for sharing their experience and expertise with the session attendees and for their contributions to this special publication.

The use of a Performance-Based Seismic Design (PBSD) approach to design buildings whose heights exceed 240 ft (73 m) has become common in many West Coast cities. This paper studies trends across 14 special reinforced concrete shear wall PBSD towers designed within the last 5 years. The primary purpose of evaluating these trends is to compare demands calculated using a linear elastic design approach (i.e. for Design Earthquake or Service Level shaking) to the demands (average results from 7 or 11 ground motions) determined through nonlinear analysis (i.e. for Maximum Considered Earthquake shaking). The specific demands evaluated include core wall shears and foundation overturning moments. The paper also demonstrates that shear and moment amplification are significant phenomena for concrete buildings, and are believed to be primarily due to nonlinear behavior, material over-strength, higher mode effects, and damping and stiffness assumptions. The results present a useful range of trends to provide an engineer guidance on the expected demands and the level of variability between projects. The paper highlights some of the reasons for the variability in these trends, and provides general proportioning recommendations.

The distribution of forces through floor diaphragms is critical to the overall behavior and performance of buildings during both wind and seismic events. Simplified methods commonly employed by design engineers establish approximate magnitudes and distributions of inertial and transfer forces within floor diaphragms. Such methods can be appropriate for regular low-rise buildings without significant transfer forces. However, for design of complex structures with large stiffness discontinuities in vertical or horizontal directions, a more detailed investigation and modeling of diaphragm behavior is usually required. Common situations in high-rise projects include a tower stack meeting a podium base with supplemental shear walls and a tower stack meeting a grade-level slab enclosed by basement walls. Large diaphragm transfer forces typically occur at these levels of abrupt stiffness changes. Using examples from recent projects and parametric studies following performance-based seismic design (PBSD) principles, this paper describes the use of strut-and-tie models in commercially available software (PERFORM-3D) to provide a better understanding of complex diaphragm behavior. Results can aid the designer in making decisions regarding floor thickness and reinforcing layout, including at chords and collectors. While the need for enhanced modeling techniques and understanding of diaphragm behavior has been highlighted by the increased use of PBSD, the findings presented in this paper may be applicable to projects based on traditional (code-based) approaches as well.

The rapid development of tall building construction has taken place in Indonesia over the last decade, especially in its capital, Jakarta. Reinforced concrete has been the preferred material of choice used for these buildings because it is economical and is easily handled by local contractors. Along with this rapid development, the Indonesian codes for structural design practices have experienced major changes, following the latest development of USA building design codes and performance-based design guidelines, especially those related to seismic design. This paper describes the latest seismic code in Indonesia and presents the state-of-the-practice for the design of tall buildings there. It also discusses the use of performance-based seismic design as an alternative method of design, considering the risk-targeted maximum and service earthquakes, in the structural design of a tall residential tower in Jakarta.

This paper summarizes the benefits and challenges of implementing performance-based seismic design (PBSD) for two concrete buildings of the Lower Sproul Plaza Redevelopment Project in one of the busiest areas of the UC Berkeley campus. The project included new construction of Eshleman Hall and the additions to Martin Luther King (MLK) Hall, and the seismic retrofit of the existing MLK Student Union as a result of the expansion. The peer-reviewed PBSD implemented three-dimensional nonlinear response history analyses at two levels of seismic hazard. The analytical simulations using pairs of near-fault ground motions, scaled to match the site-specific spectrum, were intended to establish the expected seismic behavior of the buildings under rare and frequent earthquakes. The choice of PBSD over code-prescriptive procedures was prompted by multiple layers of complexity of the project. Several challenges including those related to the horizontal and vertical irregularities, or connecting new and existing concrete buildings with different lateral force-resisting systems would have made a code-prescriptive design a cumbersome analytical endeavor without providing reliable insight about the expected seismic behavior of the buildings. The PBSD, however, proved a powerful framework to design for a reliably predictable seismic behavior with sufficient ductility, and a designated ductile hinge zones with sufficient confinement and shear capacity. The PBSD methodology also enabled the designers to avoid unnecessary conservatism to deal with the complexities, when designing drift- and acceleration-sensitive elements including the cladding system. Finally, the PBSD methodology allowed the design to consider all potential modes of failure of concrete elements retrofitted by FRP material including the debonding failure between FRP material and substrate.