1. The University of Wisconsin at Milwaukee, Department of Civil Engineering and Mechanics, EMS, P.O. Box 784, Milwaukee, Wisconsin 53201, USA, Telephone: 1/414-229-4131, Telefax: 1/414-229-6958
2. The University of Texas at San Antonio, Division of Engineering, 6900 North Loop 1604 West, San Antonio, Texas 78249-0665, USA