Performance-Based Seismic Design
Performance Based Design (PBD) is a rational approach to the design of a new building or evaluation of an existing structure that often engenders superior results when compared to conventional code-prescribed design approaches. With PBD the structural engineer works with the owner to identify specific structural performance objectives for serviceability and strength; the structure is then designed or evaluated to ensure compliance with the agreed objectives.
For several years Dr. Mehdizadeh has used PBD extensively to deal with extreme dynamic loadings due to earthquakes and has accomplished his Ph.D. in this field in 2014. More recently, Dr. Shirazi has used nonlinear performance based design, PERFORM-3D Model, for a 33-story residential tower in downtown Los Angeles.
The residential tower will be a single structure rising 33 levels to the roof with an approximate height of 360 ft. with mechanical penthouses rising to 395 ft. It will have 25 floors of residential, over 8 levels of above grade parking; the ground floor is shared with parking, retail, and residential lobby, with 3 levels of subterranean parking.
The building is designed using the alternate (non-prescriptive) performance-based approach in accordance with the guidelines of the Los Angeles Tall Building Structural Design Council’s Edition of the “Alternative Procedure for Seismic Analysis and Design of Tall Buildings Located in the Los Angeles Region,” referred to as LATBSDC Guidelines. This code provision permits the application of alternative lateral force procedures using rational analysis based on well-established principles of mechanics such as seismic performance based design approach to serve and achieve higher seismic performance objectives and also provide more cost-effective designs.