Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 30855
Finite Element Analysis of Raft Foundation on Various Soil Types under Earthquake Loading

Authors: Qassun S. Mohammed Shafiqu, Murtadha A. Abdulrasool


The design of shallow foundations to withstand different dynamic loads has given considerable attention in recent years. Dynamic loads may be due to the earthquakes, pile driving, blasting, water waves, and machine vibrations. But, predicting the behavior of shallow foundations during earthquakes remains a difficult task for geotechnical engineers. A database for dynamic and static parameters for different soils in seismic active zones in Iraq is prepared which has been collected from geophysical and geotechnical investigation works. Then, analysis of a typical 3-D soil-raft foundation system under earthquake loading is carried out using the database. And a parametric study has been carried out taking into consideration the influence of some parameters on the dynamic behavior of the raft foundation, such as raft stiffness, damping ratio as well as the influence of the earthquake acceleration-time records. The results of the parametric study show that the settlement caused by the earthquake can be decreased by about 72% with increasing the thickness from 0.5 m to 1.5 m. But, it has been noticed that reduction in the maximum bending moment by about 82% was predicted by decreasing the raft thickness from 1.5 m to 0.5 m in all sites model. Also, it has been observed that the maximum lateral displacement, the maximum vertical settlement and the maximum bending moment for damping ratio 0% is about 14%, 20%, and 18% higher than that for damping ratio 7.5%, respectively for all sites model.

Keywords: Seismic Behavior, damping ratio, shallow foundation, raft thickness

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 476


[1] M. T. Yılmaz, O. Pekcan and B. S. Bakır, “Undrained cyclic shear and deformation behavior of silt-clay mixtures of Adapazarı, Turkey,” Soil Dynamics and Earthquake Engineering, vol. 24(7), pp:497-507, 2004.
[2] V. K. Puri and S. Prakash, “Shallow Foundations for Seismic Loads: Design Considerations,” (April 29, 2013), International Conference on Case Histories in Geotechnical Engineering. Paper OSP6, 2013.
[3] Q. S. Mohammed Shafiqu and M. A. Abdulrasool, “Database of Dynamic Soil Properties for Most Iraq Soils,” American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS), Vol. 37, No. 1, pp. 230-254, 2017.
[4] PLAXIS 3D Manual, Delt University of Technology & PLAXIS, Netherland, 2013.
[5] S. S. Tezcan, Z. Ozdemir and A. Keceli, “Seismic Technique to Determine the Allowable Bearing Pressure for Shallow Foundations in Soils and Rocks,” Act a Geophysical, vol.57, no.2, 2009.
[6] FEMA, “2009 NEHRP Recommended Seismic Provisions: Design Examples,” FEMA P-751 - September 2012, Federal Emergency Management Agency, National Earthquake Hazards Reduction Program (NEHRP), 2012.
[7] R. May, “The Seismic Design of Shallow Foundations: A State of the Art Exploration,” SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World9-10 July 2015, Cambridge UK., 2015.
[8] A. P. Yadav and S. M. Jawaid, “Seismic Bearing Capacity and Settlements of Foundations,” International Journal of Innovative Research in Science, Engineering and Technology, vol. 5, issue 4, pp: 5946-5954, 2016.
[9] M. N. J. Priestley, G. M. Calvi, and M. J. Kowalsky, “Displacement-Based Seismic Design of Structures,” IUSS Press, Pavia, Italy, 2007.