Effect of the vertical component of the earthquake acceleration on the seismic bearing capacity factors of strip footings

Document Type : Original Article

Authors

1 Department of Geotechnical Engineering., International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran

2 Department of Geotechnical Enginerring, Science and Research Branch, Islamic Azad University, Tehran, Iran

3 International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, I. R. of Iran

Abstract

In this paper, the effect of the the vertical component of the earthquake acceleration on the seismic bearing capacity factors (i.e. Nq, Nc and Nγ) are investigated by employing the method of stress characteristics. By mixing the differential equations of stress equilibrium and the Moher-coulomb failure criterion, a system of plastic equilibrium equations is obtained. The generated stresses in the soil mass under the foot surface and next to it in limit state is calculated by solving plastic equilibrium equation system with the method of characteristics. Results show that, the effect of the vertical component of the earthquake acceleration in absence of horizontal component will cause reduction of the bearing capacity factors Nq, Nγ; because having no effect on Nc.The effect of the vertical component of the earthquake acceleration associated with horizontal component will cause reduction resonance on the seismic bearing capacity factors. Using the principle of superposition to obtain of the ultimate bearing pressure of the footing can be a safety.

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References

1- میر ابوطالبی. (1384)، " ظرفیت باربری لرزه‌ای شالوده‌های سطحی با در نظر گرفتن اینرسی توده خاک"  نشریه دانشکده فنی، جلد 39 شماره 3، صفحه 319 تا 327.‎
2. Richards R., Glms D. G. and Badhu M., (1993), “Seismic Bearing Capacity ad Settlement of Foundations”, Geotech. Engrg. Div., Am. Soc. Civ. Engrs., 1993, 119 No. 4, 662-674.
3. Budhu, M. and Al-Karni, A. (1993), “Seismic Bearing Capacity of Soils”, Geotechnique, Vol. 43, No. 1, pp 181-187.
4. Dormieux, L and Pecker, A. (1995), “Seismic Bearing Capacity of Foundation on Cohesionless Soil”, J. Geotech. Engrs., ASCE 121 (3), pp 300-303.
5. Soubra, A.H. (1997), “Seismic Bearing Capacity of Sallow Strip Footings in Seismic Conditions” Proc. Ins. th. Civ. Engrg, London, 125 (94), pp 230-241.
6. Soubra, A.H (1999), “Upper Bound Solution for Bearing Capacity of Foundations”, J. Geotechnical and Geo Environmental Engineering, ASCE, Vol. 125, No. 1, pp 59-68.
7. Zhu, D. (2000), “The Least Upper-Bound Solution for Bearing Capacity Factor”, Soils and Foundations, Vol 40, No. 1, pp 123-129.
8. Askari, F, and Farzaneh O. (2003), “Upper-Bound Solution for Seismic Bearing Capacity of shallow Foundation near Slopes”, Geotechnique, Vol. 53, No. 8, pp 697-702.
9. Kumar, J and V. B. K. Mohan Rao (2002), “Seismic Bearing Capacity Factors for Spread Foundation”, Geotechnique, Vol. 52, No. 2. pp 79-88.
10. Kumar, j & V. B. K. Mohan Rao (2003), “Seismic Bearing Capacity of Foundation on Slopes”, Geotechnique, Vol. 53, No 3 pp 347-361.
11- دریا باری (1385)، "تعیین ظرفیت باربری لرزه‌ای پی‌های نواری با استفاده از روش خطوطمشخصه" رساله کارشناسی ارشد، دانشگاه آزاد اسلامی واحد علوم و تحقیقات.
12. Cascone, E., & Casablanca, O. (2016), “Static and seismic bearing capacity of shallow strip footings”, Soil Dynamics and Earthquake Engineering, 84, 204-223.
New Approaches in Civil Engineering
Volume 1, Issue 1
December 2017
Pages 1-13

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