1. Graduate Research Assistant, Dept. of Civil Engineering, Univ. of Nebraska, Lincoln, NE 68588-0531.
2. Associate Professor, Dept. of Civil Engineering, Univ. of Nebraska, Lincoln, NE 68588-0531 (corresponding author).
3. Postdoctoral Research Associate, Univ. of Nebraska, Lincoln, NE 68588-0531.
4. Professor, Dept. of Engineering Mechanics, Univ. of Nebraska, Lincoln, NE 68588-0531.