1. Prof., Dept. of Civ. Engrg. Rensselaer Polytechnic Inst., Troy, N.Y. 12181
2. Grad. Student, Dept. of Civ. Engrg., Rensselaer Polytechnic Inst., Troy, N.Y. 12181
3. Assoc. Prof., Dept. of Civ. Engrg., Rensselaer Polytechnic Inst., Troy, N.Y. 12181
4. Prof., Dept. of Civ. Engrg., Univ. of Texas, Austin, Tex. 78712