Downloaded 05 Dec 2008 to 222.90.76.165. Redistribution subject to ASCE license or copyright; see http://pubs.asce.org/copyright Downloaded 05 Dec 2008 to 222.90.76.165. Redistribution subject to ASCE license or copyright; see http://pubs.asce.org/copyright Downloaded 05 Dec 2008 to 222.90.76.165. Redistribution subject to ASCE license or copyright; see http://pubs.asce.org/copyright Downloaded 05