Notes
Memorandum dated January 9, 2002, from Barry S. Chen, P.E., and Michael Bailey, P.E., Hart Crowser, Inc., to Jim Thomson, P.E., HNTB (project 4978-30), reviewing RECo 30% design for NSA, West, and South/MSE walls of the Sea-Tac Third Runway Embankment Project. Hart Crowser performed independent limit equilibrium analyses (SLOPE/W) and FLAC finite difference modeling to verify AASHTO stability criteria for steady state, end-of-construction, pseudo-static, and post-earthquake liquefaction conditions for global and compound failure modes. Recommends increasing steel strip thickness from 50×4 mm to 50×6 mm in upper tiers for all three walls, adding approximately 2.5 to 5 feet of embedment with additional reinforcing strips at specified stations on the NSA Wall (Stations 43+12 to 54+00) and West Wall (Stations 178+60 to 186+15). CC’d to John Sankey, RECo, and Rob Millar, HNTB. AR 053230–053232.