Virote Boonyapinyo, Pennung Warnitchai and Nuttawut Intaboot

pp. 1033 - 1048

Abstract

Seismic capacity evaluation of post-tensioned concrete slab-column frame buildings designed only for gravity loads and wind load is presented. The series of nonlinear pushover analyses are carried out by using the computer program SAP2000. An equivalent frame model with explicit transverse torsional
members is introduced for modeling slab-column connections. The analyses are carried out by following guidelines in ATC-40 and FEMA-273/274, where several important factors such as P-Delta effects, strength and stiffness contributions from masonry infill walls, and foundation flexibility are well taken into account.
The pushover analysis results, presented in the form of capacity curves, are compared with the seismic demand from the expected earthquake ground motion for Bangkok and then the seismic performance can be evaluated. Numerical examples are performed on the 9- and 30-storey post-tension flat-plate buildings
in Bangkok. The results show that in general post-tensioned concrete slab-column frame buildings without shear wall possess relatively low lateral stiffness, low lateral strength capacity, and poor inelastic response characteristics. The evaluation also shows that the slab-column frame combined with the shear wall system
and drop panel can increase the strength and stiffness significantly.

Keywords

• seismic evaluation
• pushover analysis
• concrete buildings
• slab-column frames