Effect of Confinement on the Bearing Capacity and Settlement of Spread Foundations
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Effect of Confinement on the Bearing Capacity and Settlement of Spread Foundations

Authors: Tahsin Toma Sabbagh, Ihsan Al-Abboodi, Ali Al-Jazaairry

Abstract:

Allowable-bearing capacity is the competency of soil to safely carries the pressure from the superstructure without experiencing a shear failure with accompanying excessive settlements. Ensuring a safe bearing pressure with respect to failure does not tolerate settlement of the foundation will be within acceptable limits. Therefore, settlement analysis should always be performed since most structures are settlement sensitive. When visualising the movement of a soil wedge in the bearing capacity criterion, both vertically and horizontally, it becomes clear that by confining the soil surrounding the foundation, both the bearing capacity and settlement values improve. In this study, two sizes of spread foundation were considered; (2×4) m and (3×5) m. These represent two real problem case studies of an existing building. The foundations were analysed in terms of dimension as well as position with respect to a confining wall (i.e., sheet piles on both sides). Assuming B is the least foundation dimension, the study comprised the analyses of three distances; (0.1 B), (0.5 B), and (0.75 B) between the sheet piles and foundations alongside three depths of confinement (0.5 B), (1 B), and (1.5 B). Nonlinear three-dimensional finite element analysis (ANSYS) was adopted to perform an analytical investigation on the behaviour of the two foundations contained by the case study. Results showed that confinement of foundations reduced the overall stresses near the foundation by 65% and reduced the vertical displacement by 90%. Moreover, the most effective distance between the confinement wall and the foundation was found to be 0.5 B.

Keywords: Bearing capacity, cohesionless soils, spread footings, soil confinement, soil modelling.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.2021831

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References:


[1] Lambe W T & Whitman R V (1969),” Soil Mechanics", 2nd edition, John Wiley & Sons, NY.
[2] Winterkorn H F (1975), "Foundation Engineering Hand Book" Van Nostrand Reinhold Co.
[3] Al-Aghbari M Y (2007), “Settlement of Shallow Circular Foundations with Structural Skirts Resting on Sand”, the Journal of Engineering Research Vol. 4, No.1, 11-16.
[4] Vesic A (1963), "Bearing capacity of deep foundations in sand" Highway research Record, No. 39.
[5] Frydman S and Burd H J (1997), ”Numerical Studies of Bearing Capacity Factor Nγ”, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 123, No.1, 20-29.
[6] Hisham T E (2013), ”Bearing Capacity and Settlement of Skirted Shallow Foundations on Sand” International Journal of Geomechanics, ASCE, Vol. 13, No.5, 645–652.
[7] Shabana S K and Joseph M (2010), “Effect of Structural Skirt on Square Footing” http://117.211.100.42:8180/jspui/bitstream/123456789/1063/1/CEGE10.pdf.
[8] Azzam W R and Farouk A (2010), “Experimental and Numerical Studies of Sand Slopes Loaded with Skirted Strip Footing”, Electronic Journal of Geotechnical Engineering, Vol. 15 No.3, 795-812.
[9] Nazir A K and Azzam W R (2010), “Improving the bearing capacity of footing on soft clay with sand pile with/ without skirts”, International Review of Civil Engineering Journal, Vol.1, No.1, 32-38. doi: 10.1016/j.aej.2010.06.002.
[10] El-Sawwaf M (2005),"Behavior of circular footing resting on confined granular soil", Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 131 (3), 359-366.
[11] Cerato A B (2000), "Model footing test on finite layer of granular soil" graduate research assistant, university of Massachusetts, Amherst, USA 2000.
[12] Anderson S A (1995), "Collapse of saturated soil due to reduction in confinement" Journal of Geotechnical Engineering, Vol. 121, No. 2, 216-220.
[13] Prakoso W A and Kulhawy F H (2001), “Contribution to Piled Raft Foundation Design Journal of Geotechnical and Geoenvironmental Engineering”, ASCE, 127(1), 17-24.