Notes

Memorandum dated November 9, 2000 from Barry Chen, P.E. of Hart Crowser to Jim Thomson, P.E. of HNTB (J-4978-30), reviewing RECo’s 30% design for NSA, West, and South MSE (Mechanically Stabilized Earth) walls for the Third Runway Embankment Project at Sea-Tac Airport. Using SLOPE/W limit equilibrium analyses and FLAC displacement-based modeling, Hart Crowser identified marginal factors of safety for compound stability at Station 186+00 (West Wall) and Stations 142+75 and 147+25 (South Wall), and marginal global stability at Station 147+25. Proposed design modifications include increasing steel strip thickness from 50×4 mm to 50×6 mm and increasing embedment depth and strip length by 2 feet. FLAC analyses of 475-year seismic events show maximum horizontal deformations of 10 inches (West Wall) and 14 inches (South Wall) at top of wall. CC: Mike Bailey, John Sankey (RECo), Pete Douglas.

Sidebar On/Off

As the source for federal transportation grants, the Puget Sound Regional Council was charged with developing a system to meet the growing need for commercial aviation. When the search for a second airport failed, they authorized the Port of Seattle to build the Third Runway, with a mandate to develop a noise abatement and mitigation program. In their effort to stop the Third Runway, the ACC argued over every detail of the Port's efforts--including property buyouts and sound insulation. The dispute was meant to be settled by a three member Expert Arbitration Panel. This is their final report. It finds 2-1, that the Port's program was insufficient in several respects. Despite that, funding for the Third Runway was approved by the PSRC, and the 'Port Package' program, proceeded largely unchanged. Expert Arbitration Panel's final decision finding that the Port of Seattle had not shown sufficient reduction in real on-the-ground noise impacts to satisfy noise reduction conditions required for approval of a third runway at Sea-Tac International Airport. The majority decision concluded the Port's noise abatement programs were insufficient despite being impressive in scope.

continue...

V V

Notes

Message