Seismic Performance of a Deep Soil Mixing Grid: A Magnitude 7.1 Load Test at the Port of Alaska

by Samuel R. Christie, P.E., Principal professional/senior project manager with Kleinfelder in Seattle, WA., SChristie@Kleinfelder.com.,
Stephen E. Dickenson, P.E., Ph.D., (M.ASCE), President of New Albion Geotechnical, Inc. in Reno, NV., sed@newalbiongeotechnical.com.,
Paul Guenther, P.E., Office manager for COWI North America in Seattle, WA., page@cowi.com.,
Sharon A. Walsh, S.E., Port of Alaska modernization program director, overseeing the planning, programming, design, and construction of the new Petroleum and Cement Terminal., sharen.walsh@anchorageak.gov,
, P.E.


2021


Serial Information: Geo-Strata —Geo Institute of ASCE, 2021, Vol. 25, Issue 4, Pg. 32-38


Document Type: Feature article

Abstract: The Port of Alaska in Anchorage (Port) has embarked on a multiphase modernization program that includes the development of a new petroleum and cement terminal (PCT) berth. The berth consists of a pile-supported trestle that connects to a platform located offshore in the Knik Arm waterway (Figure 1). The terminal is located in a dynamic marine environment with numerous design challenges, including tidal fluctuations of as much as 40 ft, design ground motions associated with a magnitude Mw 9.3 subduction zone earthquake, weak foundation soils, and shoreline conditions that are vulnerable to large-scale seismic displacements. Geotechnical input to the seismic design of the pile-supported terminal required synthesis of extensive in-situ and cyclic laboratory testing data, nonlinear deformation analysis (NDA), and layout of a deep soil mixing (DSM) ground improvement zone for mitigation of seismically induced slope displacements.

Subject Headings: Seismic tests | Seismic design | Soil mixing | Ports and harbors | Foundation design | Laboratory tests | Seismic loads | Load tests | Alaska | United States

 

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