Application of yield line theory in pre-cast waffle slab

Abstract

Analysis of precast waffle slabs have concentrated on the rib portions, while the slab portion were left unanalyzed. This has led to cracks or outright failure of the slab portions due to under reinforcement. This paper proposed the use of yield line theory in solving this problem. Yield line theory was adopted to develop a computer program called YLRGT in the analysis of pre-cast waffle slabs. Three panels with dimensions 6m x 6m, 6m x 5m and 5m x 2m were analyzed, and the results were compared with an existing analytical method which was based on the BS 8110 slab coefficient factor. YLRGT analyzed the slab portion effectively, unlike the BS 8110 where approximate values were adopted for the slab portion. The paper concluded that the slab portion of pre-cast waffle slabs can be effectively analyzed using the computer program.

Keywords: Waffle slabs, Yield line theory, Panels, YLRGT