Notes
Hart Crowser memorandum (J-4978-19) from Michael Bailey, P.E., to Port Of Seattle attn. Michael J. Cheyne, CC HNTB attn. Jim Thomson, P.E., dated March 26, 2001, summarizing MSE (Mechanically Stabilized Earth) wall performance during the February 28 Nisqually earthquake. Discusses two MSE walls identified by Helsell Fetterman (Eglick & Stock 3/20/01) and GeoSyntec (3/15/01) as having earthquake problems: (1) a 9-to-12-foot high MSE wall in Tumwater that collapsed, using plastic reinforcing, with a broken water pipe and prior site failure; (2) MSE wall at north end of Terminal 5, Port of Seattle, where EERI and University of Washington reported liquefaction-caused movement, sand boils on APL property, ground cracks 1-2 inches wide 300 feet long, and 2-inch settlement near buildings. Hart Crowser concluded neither T-5 wall failed significantly. Also notes a 17-foot MSE wall at a Costco in Tacoma sustained slope failure and wall bulge. RECo wall, steel reinforcing, liquefaction, and foundation subgrade issues discussed.