1. Asst. Prof., Dept. of Civ. Engrg., Univ. of Pittsburgh, Pittsburgh, Pa.; formerly, Research Assoc., Dept. of Civ. Engrg., Massachusetts Inst. of Tech., Cambridge, Mass.
2. Struct. Engr., Iglesias, Vazques, del Nedo, and Bonnet, Puerto Rico;formerly, Research Asst., Dept. of Civ. Engrg., Massachusetts Inst. of Tech., Cambridge, Mass.
3. Assoc. Prof., Dept. of Civ. Engrg., Massachusetts Inst. of Tech., Cambridge, Mass.