Characterizing the Load Environment of Ferry Landings for Washington State Ferries and the Alaska Marine Highway System

Anybody riding a ferry wants it to dock safely — and for port managers, having passengers and goods in the water is never a good thing. This project aims to mitigate uncertainty and assumptions about load demands on ferry terminal structures, specifically, ferry landing structures. The project will provide information needed to safely and efficiently design ferry berthing and landing facilities, decrease the uncertainty in design criteria, and remove assumptions associated with procedures traditionally used to design these structures. For Alaska Marine Highway System facilities, loads imposed on dolphin structures and mooring line loads are of most concern. Due to a lack of information about the magnitude of these loads or how they may be determined, AMHS engineers are forced to make (sometimes gross) design assumptions. The Washington State Ferry System also confronts these uncertainties, specifically in the design of wingwall structures that accept vessels during loading/unloading of passengers and vehicles. While the structures used by AMHS and WSFS have fundamental differences, the metrics needed to determine appropriate design criteria are the same. Thus, the instrumentation used to monitor these facilities in operation is also similar. These similarities present an opportunity for a cost-sharing project in which the ADOT&PF and Washington State DOT are able to leverage research funding and benefit from a much more comprehensive project than either might be able to support individually. To achieve this project’s goals, the research team will acquire a robust statistical sample of the metrics (strains and displacements) needed to define the design criteria (loads from vessels and waves). The data will be gathered via in situ monitoring of in-service facilities, specifically, the AMHS terminal at Auke Bay near Juneau, Alaska, and the WSF Seattle terminal in Washington.