Recent devastating earthquakes in some countries, such as Pakistan, Turkey, Algeria and China, call to the mind the high risk exposure of Lebanon which is located over an active seismic zone. Many experts shared the view that major seismic event may occur in Lebanon in the future. Moreover, many earthquakes, of low magnitudes between three and four, have been registered in Lebanon during 2008. These events have increased the anxiety of Lebanese people because of the poor quality of the constructions and their behavior under moderate or severe earthquake events. The efficient way to minimize seismic effects, material and human losses, is the prevention. The system piles-foundation is an appropriate way and widely used to ensure the stability of constructions when subjected to seismic excitation. It seems necessary to study the interaction of pile-foundation-pile-cap-structure in the case of non linear soil behavior and the interface pile-soil. The study will be also conducted by using measures recorded during real earthquakes for example in Turkey (Kocaeli, 1999). In this paper, we present a numerical modeling of the interaction of using FLAC3D software. According to soil behavior and pile inclination, parametric studies are also performed. The analysis of the results could give the better piles group configuration in order to minimize the seismic effect on the structures.
 R. W. Boulanger, C. J. Curras, D. W. Wilson and A. A. Abghari, “Seismic Soil-Pile-Structure Interaction Experiments and Analyses,” Journal of Geotechnical and Geo- environmental Engineering, Vol. 125, No. 9, 1999, pp. 750-759.
 N. Gerolymos, A. Giannakou, I. Anastasopoulos and G. Gazetas, “Evidence of Beneficial Role of Inclined Piles: Observations and Summary of Numerical Analyses,” Springer Science and Business Media B. V., 2008.
 N. Gerolymos, S. Escoffier, G. Gazetas and J. Garnier, “Numerical Modeling of Centrifuge Cyclic Lateral Pile Load Experiments,” Earthquake Engineering and Engineering Vibration, Vol. 8, No. 1, 2009, pp. 61-76.
 Itasca Consulting Group, FLAC, “Fast Lagrangian Analysis of Continua,” Vol. I. User’s Manual, Vol. II. Verification Problems and Example Applications, 2nd Edition (FLAC3D Version 3.0), Minneapolis, Minnesota, 2005.
 J. P. Bardet, I. M. Idriss, O’Rourke, N. Adachi, M. Hamada and K. Ishihara, “North America-Japan Workshop on the Geotechnical Aspects of the Kobe,” Loma 138 Prieta, and Northridge Earthquake. Report No. 98-36 to National Science Foundation, Air Force Office of Scientific Research, and Japanese Geotechnical Society, Osaka, 1996.
 K. Tokimatsu, H. Arai and Y. Asak, “Deep Shear Struc- ture and Earthquake Ground Motion. Characteristics in Sumiyoshi Area, Kobe City, Based on Microtremor Measurements,” Journal of Structural Engineering (ASCE), Vol. 491, 1997, pp. 37-45.
 G. Gazetas and G. Mylonakis, “Seismic Soil-Structure Interaction: New Evidence and Emerging Issues. Emerging Issues Paper, Geotechnical Special Publication No 75, ASCE, 2111,” Soil Dynamics and Earthquake Engineering, Vol. 26, No. 6, 2006, pp. 461-468.