Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils

Expansive soils shrink and swell with drying wetting cycles. The shrink-swell capacity of expansive can result in differential movement beneath foundations which is a very common cause foundation problems. Ribbed slab, often called waffle one the efficient inexpensive solutions for use under light structures resting on soils. This paper presents numerical analysis that used to calculate displacement internal forces ribbed slab swell/shrink soil. stiffness modelled as an equivalent flat constant thickness straining actions are calculated case central heave. A parametric study effect beam dimensions rib spacing performed assess optimum configuration. Dimensioning system; thickness, depth width beams spacing, according Egyptian Code Practice design concrete structures. results show depths 0.4 m 0.45 were safe recommended this condition heave scenario. All 0.3 cannot resist resulting bending moments, While 0.35 only when not less than 0.2 m.