1. Graduate Research Assistant, School of Civil and Construction Engineering, Oregon State Univ., 101 Kearney Hall, Corvallis, OR 97331.
2. Staff Engineer, Shannon and Wilson, 3990 SW Collins Way, Lake Oswego, OR 97035.
3. Associate Professor, School of Civil and Construction Engineering, Oregon State Univ., 101 Kearney Hall, Corvallis, OR 97331 (corresponding author).