Characterizing the berthing load environment of the Seattle ferry teminal, Bremerton slip

Abstract

This manuscript characterizes and presents design recommendations for berthing demands on ferry landing structures. There is a lack of research focused on the berthing load demand imparted by ferry class vessels, therefore the load criteria used for design is often based on a number of assumptions. This study involved a one-year field study of the structural load environment of wingwalls at the Bremerton Slip of the Seattle Ferry Terminal, located in Elliott Bay adjacent to Seattle, Washington. Measurements of marine fender displacement, vessel approach distance with respect to time, and. pile strain were used to determine berthing demands. Berthing event parameters were characterized using the Python programming language, compiled, and analyzed statistically. Probability theory was used to provide design value recommendations for berthing energy, force, approach velocity, berthing factor, and berthing coefficient. This study presents a number of engineering design aids intended to quantify the berthing load environment of wingwalls in the Washington State Ferry System.