1. Professor and Holder of the Buchanan Chair, Zachry Dept. of Civil Engineering, Texas A&M Univ., College Station, TX 77843-3136 (corresponding author).
2. Assistant Professor, Dept. of Civil Engineering, Faculty of Engineering, El-Minia Univ., El-Minia, Egypt.
3. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Alaska Fairbanks, Fairbanks, AK 99775.
4. Geotechnical Engineer, Geotech Engineering and Testing, 800 Victoria Dr., Houston, TX 77022.