Los Angeles Tall Building Design Council (LATBDC) 2005 guidelines for analysis and design of tall buildings are utilized for the design of a 40 storey tall reinforced concrete building located in downtown Los Angeles. The case study structure is a 415 feet tall reinforced concrete residential building with 118 feet by 96 feet plan area. Lateral load carrying system of the building is bearing walls coupled with 32 to 60 inches deep spandrel beams. Gravity system consists of 8" thick post-tensioned concrete flat slabs resting on reinforced concrete gravity columns and bearing walls. Linear and nonlinear dynamic analysis procedures were followed using 475 and 2,475 year return period seismic events respectively. Design of core wall segments and spandrel beams connecting the segments together were controlled by both of these seismic hazard levels and analysis procedures. Nonlinear dynamic analysis of the 40 storey building showed inelastic flexural response at the spandrel beams over the building height in addition to the first few levels of the core wall segments. As intended, recorded component deformations were within the collapse prevention performance limits set by FEMA 356. The case study results highlight a significant limitation for Step 2 (Life Safety for DBE) to demonstrate achievement of 'life safety'.
展开▼
