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SP T Foundation

The document presents a deterministic design approach for shallow foundations using Standard Penetration Test (SPT) data, detailing input values, calculations for bearing capacity, and allowable stress for various foundation widths and depths. It includes equations from established sources, such as Terzaghi and Meyerhof, and provides results for ultimate capacity and allowable stress under different methods. Additionally, it outlines deformation criteria and references key literature in geotechnical engineering.

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Mahmoud Atia
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50 views3 pages

SP T Foundation

The document presents a deterministic design approach for shallow foundations using Standard Penetration Test (SPT) data, detailing input values, calculations for bearing capacity, and allowable stress for various foundation widths and depths. It includes equations from established sources, such as Terzaghi and Meyerhof, and provides results for ultimate capacity and allowable stress under different methods. Additionally, it outlines deformation criteria and references key literature in geotechnical engineering.

Uploaded by

Mahmoud Atia
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLS, PDF, TXT or read online on Scribd
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DETERMINISTIC SHALLOW FOUNDATION DESIGN USING SPT DATA

Version 1.0
developed by Dimitris P. Zeccos, available by the Geoengineer Website
Input values
N 20
ER 60
SPT Correction factors
Cs 1
Cr 1
Cb 1
Ce 1
N60 25
D/B 0.5
effective unit weight (kN/m^3) 9.23
Foundation Width (m) 1 1.5 2 2.5 3
Depth of interest (m) 1 1.5 2 2.5 3
Vertical effective stress (kPa) 9.23 13.845 18.46 23.075 27.69
Liao&Witman depth correction factor 0.3038 0.3721 0.4297 0.4804 0.5262
N1,60 50.00 50.00 50.00 50.00 47.51
TERZAGHI BEARING CAPACITY EQUATION FOR SANDS
Applied Factor of Safety 3.00
Using Hatanaka & Uchida (1996), Mayne (2001) equation
Friction angle (degrees) 47.7 47.7 47.7 47.7 47.0
Ngamma (Chen) 661.2 661.2 661.2 661.2 569.7
Ngamma (Brinch-Hansen) 349.7 349.7 349.7 349.7 302.5
Nq (same for all) 212.8 212.8 212.8 212.8 188.8
Ultimate capacity (kPa) 2596.2 3894.2 5192.3 6490.4 6802.1
Allowable stress (kPa) 865.4 1298.1 1730.8 2163.5 2267.4
Using De Mello (1971), Schmertmann (1975) and Mayne (2001) equation
Friction angle (degrees) 50.6 49.9 49.4 48.8 48.3
Ngamma (Chen) (not used) 1240.5 1075.6 942.5 833.6 743.3
Ngamma (Brinch-Hansen) 645.1 561.5 493.8 438.2 392.0
Nq (same for all) 354.7 315.7 283.6 256.6 233.9
Ultimate capacity (kPa) 4614.2 6072.8 7175.3 8017.1 8664.9
Allowable stress (kPa) 1538.1 2024.3 2391.8 2672.4 2888.3
Using Empirical Meyerhof (1956) equation for bearing capacity
Ultimate capacity (kPa) 615.2 922.8 1230.4 1538.0 1845.6
Allowable stress (kPa) 205.1 307.6 410.1 512.7 615.2
DEFORMATION CRITERION
Using Burland & Burbridge (1984) Approach
Allowable settlement (mm) 25.4
Inducing mean-σ stress (KPa) 741.2 558.1 456.3 390.3 343.5
Inducing mean stress (kPa) 1348.8 1015.5 830.3 710.2 625.1
Inducing mean+σ stress (KPa) 2454.4 1847.9 1510.9 1292.4 1137.5

page 2 of 2
Allowable stress, kPa

Allowable Stress
3500.0
3000.0
2500.0
2000.0
1500.0
1000.0
500.0
0.0
0.5 1 1.5 2 2.5 3 3.5
Foundation width, m
Bearing Hatanaka Bearing Schmertman
Meyerhoff Burland mean stress
Burland mean-σ stress Burland mean+σ stress

Notes:
Methods developed according to correlations provided in the references. No responsibility is
assumed for the results of the spreadsheet.
The values in the yellow boxes are those that the user can change.
Corrections for the blowcount according to Youd et al (2001)

References:
Burland, J.B., Burbidge, M.C. (1984), Settlement of foundations on sand and gravel, Proceedings of the
Institution of Civil Engineers, Part 1, 1985, 78, Dec., 1325-1381.
Hatanaka, M., Uchida, A. (1996). Empirical correlation between penetration resistance and effective friction of
sandy soil. Soils & Foundations, Vol. 36 (4), 1-9, Japanese Geotechnical Society.
Mayne, P.W. (2001), Geotechnical site characterization using Cone, piezocone, SPTu, and VST, Civil and
Environmental Engineering Department, Georgia Institute of Technology
Meyerhof, G.G. (1956), Penetration tests and bearing capacity of cohesionless soils, Journal of the soil
mechanics and foundation division, ASCE, Vol. 82, No. SM1, January, pp. 1-19.
Schmertmann, J.H. (1975), Measurement of insitu shear strength, keynote lecture, Proceedings of the
conference on in-situ measurement of soil properties, June 1-4, 1975, vol. II, American Society of Civil
Engineers.
3.5

man
ess
stress

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