Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils
Khedr, N., Shehab Eldin, H., Ata, A., Mohamed, H. (2021). Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils. EKB Journal Management System, 33(Civil and Architectural Engineering), 8-16. doi: 10.21608/eijest.2021.54338.1032
Norhan Samir Khedr; Hamdy Shehab Eldin; Alaa Ata; Heba A. Mohamed. "Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils". EKB Journal Management System, 33, Civil and Architectural Engineering, 2021, 8-16. doi: 10.21608/eijest.2021.54338.1032
Khedr, N., Shehab Eldin, H., Ata, A., Mohamed, H. (2021). 'Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils', EKB Journal Management System, 33(Civil and Architectural Engineering), pp. 8-16. doi: 10.21608/eijest.2021.54338.1032
Khedr, N., Shehab Eldin, H., Ata, A., Mohamed, H. Design and Analysis of Ribbed Raft Foundation Resting on Swell-Shrink Soils. EKB Journal Management System, 2021; 33(Civil and Architectural Engineering): 8-16. doi: 10.21608/eijest.2021.54338.1032

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

The Egyptian International Journal of Engineering Sciences and Technology
Article 2, Volume 33, Civil and Architectural Engineering, March 2021, Page 8-16  XML PDF (1.11 MB)
Document Type: Original Article
DOI: 10.21608/eijest.2021.54338.1032
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Authors
Norhan Samir Khedr email 1; Hamdy Shehab Eldin1; Alaa Ata1; Heba A. Mohamed2
1Civil, Engineering, Zagazig, Cairo, Egypt
2civil, engineering, Zagazig, Cairo, Egypt
Abstract
Expansive soils shrink and swell with drying and wetting cycles. The shrink-swell capacity of expansive soils can result in differential movement beneath foundations which is a very common cause of foundation problems. Ribbed slab, often called waffle slab, is one of the efficient and inexpensive foundation solutions for use under light structures resting on shrink-swell soils. This paper presents a numerical analysis that is used to calculate displacement and internal forces in ribbed slab foundations resting on swell/shrink soil. The stiffness of the ribbed slab is modelled as an equivalent flat slab of constant thickness and the straining actions are calculated for the case of central heave. A parametric study of the effect of beam dimensions and rib spacing is performed to assess the optimum configuration. Dimensioning of the waffle slab system; slab thickness, depth and width of beams and spacing, is performed according to the Egyptian Code of Practice for the design of concrete structures. The results show that beam depths of 0.4 m and 0.45 m were safe and recommended under this condition of heave scenario. All beams with depths of 0.3 m cannot resist the resulting bending moments, While beams with 0.35 m depth are only safe when the beam width is not less than 0.2 m.
Keywords
Differential movement; Swell-shrink soils; Ribbed slab foundation; Waffle slabs; Central heave
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