1. Research Associate, 1111 Engineering Dr., UCB 428, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado Boulder, Boulder, CO 80309.
2. Associate Professor, 1111 Engineering Dr., UCB 428, ECOT 514, Dept. of Civil, Environmental, and Architectural Engineering, Univ. of Colorado Boulder, Boulder, CO 80309 (corresponding author).