1. Ph.D. Candidate, Missouri Univ. of Science and Technology, Rolla, MO 65409.
2. Research Structural Engineer, National Institute of Standards and Technology, Gaithersburg, MD 20899.
3. Director, National Fire Research Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899.
4. Professor and Abbett Distinguished Chair in Civil Engineering, Missouri Univ. of Science and Technology, Rolla, MO 65409 (corresponding author).