1. Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720-1710, USA, Telephone: 1/510-642-9843, Telefax: 1/510-642-7476,
2. Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, Utah 84112-0561, USA, Telephone: 1/801-585-9726, Telefax: 1/801-585-5477,