1. Assistant Professor, School of Civil and Construction Engineering, 101 Kearney Hall, Oregon State Univ., Corvallis, OR 97331 (corresponding author).
2. Bridge Designer, David Evans and Associates Inc., 2100 SW River Parkway, Portland, OR 97201; formerly, Graduate Student, Oregon State Univ., Corvallis, OR 97331.
3. Professor, School of Civil and Construction Engineering, 203 Owen Hall, Oregon State Univ., Corvallis, OR 97331.