1. Postdoctoral Researcher, Lyles School of Civil Engineering, Purdue Univ., West Lafayette, IN 47907 (corresponding author).
2. Karl H. Kettelhut Professor and Director of Bowen Laboratory, Lyles School of Civil Engineering, Purdue Univ., West Lafayette, IN 47907.
3. Technical Specialist, Engineering Design Assessment Division, Canadian Nuclear Safety Commission, P.O. Box 1046, Station B, 280 Slater St., Ottawa, ON, Canada K1P 5S9.