1. Professor, Shandong Univ., No. 73, Jingshi Rd., Jinan, Shandong 250061, People’s Republic of China; and, Texas Dept. of Transportation, 4203 Bull Creek #39, Austin, TX 78731.
2. Ph.D. Candidate, Dept. of Civil Engineering, The Univ. of Texas at Austin, 1 University Station, C1792, Austin, TX 78712-0273.
3. Professor, Shandong Univ., No. 73, Jingshi Rd., Jinan, Shandong 250061, People’s Republic of China.