Title: Response of a Post-Tensioned Floor Following a Column Loss
Author(s): Leila Keyvani and Mehrdad Sasani
Publication: Symposium Paper
Appears on pages(s): 1-18
Keywords: Concrete slabs; Flat slab; Layered shell; Membrane forces; Progressive collapse; Post-tensioned; Tension ring.
Structural response of post-tensioned floors following a severe event such as a sudden column loss is an important topic, which has not been extensively studied in the past. In this paper, the system-level response and collapse resistance of an actual post-tensioned parking garage is evaluated analytically and verified by experimental data following the sudden loss of a column. The field data demonstrated that the slab resisted collapse with a permanent maximum vertical displacement of about 2.4 in (61 mm). The development of the membrane forces and their effects on the response of the slab, particularly the region in the neighborhood of the lost column which experienced cracks at the bottom of slab, are studied analytically. According to analytical results, which are in good agreement with experimental data, slab flexural strength is increased due to formation of additional compressive membrane forces. The floor system resists the additional compressive membrane force by formation of a peripheral tensile ring.