May 14, 2001August 2, 2026

EXH AR050078: Draft Memorandum — Proposed Liquefaction Procedure Under Walls and Slopes, Third Runway Embankment

Notes

Draft memorandum dated May 14, 2001, from Douglas Lindquist (E.I.T.) and Michael Bailey (P.E.) of Hart Crowser, Inc. to Pete Douglass (P.E.) and Embankment Technical Review Board (ETRB), CC Jim Thomson (P.E.) HNTB, project 4978-30. Describes proposed liquefaction potential evaluation procedure for areas beneath walls and slopes of the Third Runway embankment at Sea-Tac Airport. Procedure accounts for ground shaking, standard penetration test (SPT) resistances, irregular topography, high confining pressures, and static shear stresses. Uses one-dimensional equivalent linear site response analyses (ProShake) and two-dimensional FLAC analyses. Discusses stone column soil improvement, cyclic stress ratio (CSR), Motions A and B from probabilistic seismic hazard analysis, limit equilibrium stability evaluation, and a scaling/adjustment procedure combining SHAKE and FLAC results.

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