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October 2017 Dinner Meeting
October 26 @ 5:30 pm - 9:00 pm
Seismic Design of Piers and Wharves ASCE61-14 and Proposed Updates to ASCE61-19
Nason J McCullough, PhD, PE, GE
Chair of the ASCE61 Geotechnical Task Committee
CH2M, Corvallis, OR
Abstract: The criteria and methodologies for seismic design of piers and wharves have evolved enormously over the last 25 years. This has happened independently of changes in the seismic design practice in the building industry, with the result that the marine industry treats seismic design differently than the building industry does. Conventional building codes are generally focused on a minimum standard for collapse prevention/life safety of the public. Marine structures are typically not-public accessible and the design is focused on performance-based evaluations to estimate loss of operation and associated downtime.
Attempts to incorporate port design practice into the building codes was unsuccessful, as the extent of differences in the industries proved to be an insurmountable obstacle. Recognizing this, the code developers for ASCE 7 decided to specifically limit the applicability of that Standard to piers and wharves that are accessible to the general public. This includes cruise terminals, ferry terminals, and marine structures supporting retail shopping or offices.
The ASCE61 Standard specifically is applicable to structures not covered by ASCE 7. ASCE61 is based on a performance-based design approach, emphasizing displacement-based analysis. The first version of ASCE61 was published in 2014, and met many of the needs of the marine community. The standard is planned to undergo revisions every 5 years, and it is currently being updated for the next revision in 2019, which will include changes to some of the design ground motions, updates on the approach to the use of live loads during seismic design, will include guidance for the seismic design of sheet pile wall used in the marine environment, as well as other changes.
This presentation will discuss the background of the ASCE61 standard, a summary of the design process per
the current version (ASCE61-14), and the proposed changes and updates for the next version (ASCE61-19). The focus of this presentation will be on the seismic hazard and geotechnical consideration for soil-structure interaction aspects of the standard.
Bio: Nason obtained a PhD in Civil Engineering from Oregon State University (OSU), majoring in Geotechnical Engineering and minoring Ocean Engineering. He currently lives and works in Corvallis, OR, and has been with CH2M since 2002. Nason is a Principal Geotechnical Engineer at CH2M and has been a courtesy faculty at Oregon State University in Geotechnical Earthquake Engineering. He has worked on port projects in Central America (Mexico and Costa Rica), Caribbean (Haiti, Dominican Republic, US Virgin Islands, and Bermuda), and South America (Ecuador). His focus has generally been with seismic design and the design of waterfront structures.
He is actively involved in the ASCE COPRI (Coastal, Ocean, Ports Research Institute) committee developing guidelines and standards for the seismic design of piers and wharves (ASCE61 committee) and bulkheads.
He has authored or co-authored around 30 papers and was involved in the development of PIANC international guidelines for the seismic design of ports.