1. Assistant Professor, LGC-Civil Engineering Laboratory, Blaise Pascal Univ. Clermont II France, 24 ave. des Landais, BP 206, 63174 Aubiere Cedex, France (corresponding author).
2. Assistant Professor, LGC-Civil Engineering Laboratory, Blaise Pascal Univ. Clermont II France, 24 ave. des Landais, BP 206, 63174 Aubiere Cedex, France.