1. Professor Emeritus in Civil Engineering, Univ. of Texas at Austin, 10100 Burnet Rd., Bldg. 177, Austin, TX 78758.
2. Assistant Professor, Univ. of Texas at Austin, 10100 Burnet Rd., Bldg. 177, Austin, TX 78758 (corresponding author). E-mail: thelwig@mail.utexas.edu
3. Research Assistant Professor, Dept. of Civil Engineering, John Hopkins Univ., Latrobe Hall 210, Baltimore, MD 21218.
4. Senior Specialist, Technip USA, 11700 Old Katy Rd., Houston, TX 77079.