1. Dept. of Civil Engineering, Univ. of Puerto Rico at Mayaguez, P.O. Box 9000, Mayaguez, Puerto Rico 00680.
2. Dept. of Environmental and Radiological Health Sciences, Colorado State Univ., 152 Campus Delivery, Fort Collins, CO 80523-1681.
3. School of Building Construction, Georgia Institute of Technology, North Ave. NW, Atlanta, GA 30332.