1. Ph.D. Student, Dept. of Civil Engineering, August 20, 1955 Skikda State Univ., B.P. 26, route d’El-Hadaiek, Skikda 21000, Algeria (corresponding author).
2. Professor, LMDC, INSA-UPS Génie Civil, Université de Toulouse, 135 Ave. de Rangueil, 31077 Toulouse Cedex 4, France.
3. Professor, Dept. of Civil Engineering, Univ. of Mentouri Constantine, B.P. 325, Route de Ain El Bey, Constantine 25000, Algeria.
4. Professor, Dept. of Civil Engineering, August 20, 1955 Skikda State Univ., B.P. 26, route d’El-Hadaiek, Skikda 21000, Algeria.