Performance based seismic design provides code alternative procedures for the design and engineering of seismic force resisting systems for tall and special buildings.
According to LADBS Information Bulletin P/BC 2023-123, “The building code provides a minimum level of safety through a series of prescriptive provisions. The prescriptive provisions are broadly applied to all types of buildings; from single story buildings to tall buildings. These building code provisions result in the application of requirements that are not specifically applicable to the design of tall buildings and buildings with complex structural systems, which may result in designs that are less optimal and less safe. Advances in performance-based design methodologies and capacity design principles allow for a more direct, non-prescriptive, and rational approach to analysis and design. The use of performance-based seismic design requires a detailed assessment of how a building will most likely perform during an earthquake event, which leads to a better understanding of the structural systems and a more accurate application of design and analysis. At the same time, it releases the design from non-applicable prescriptive restrictions.”
The Los Angeles Tall Buildings Structural Design Council (LATBSDC) document, “An Alternative Procedure for Seismic Analysis and Design of Tall Buildings Located in the Los Angeles Region,” 2023 edition (www.tallbuildings.org) is the approved alternative procedure for the seismic design of buildings. “
Use of this performance-based approach is subject to prior approval by the building official for the subject building.