Title
Partial safety factors for berthing velocity and loads on marine structures
Author
Roubos, A.
Peters, D.J.
Groenewegen, L.
Steenbergen, R.D.J.M.
Publication year
2018
Abstract
Design methods for marine structures have evolved into load and resistance factor design, however existing partial safety factors related to berthing velocity and loads have not been verified and validated by measurement campaigns. In this study, field observations of modern seagoing vessels berthing in Bremerhaven, Rotterdam and Wilhelmshaven were used to evaluate partial safety factors for berthing energy and berthing impact loads. Various types of vessels and navigation conditions were statistically examined. The results show that characteristic values of berthing velocity with a return period of 50 years are in line with design recommendations in literature. Design values of berthing velocity are sensitive to the number of berthing operations during the lifetime of a marine structure. Typical partial safety factors for sheltered and exposed navigation conditions were derived by extrapolating distribution fits and applying extreme value theory. Differences in structural response due to soil stiffness and the type of berthing system installed influence partial safety factors for berthing impact loads. The probability of an uncontrolled berthing event was higher for exposed navigation conditions (strong tidal currents). In these circumstances, higher partial safety factors for berthing velocity should be considered in the design of marine structures. When berthing aid systems are used, the probability of extreme berthing velocities is lower, resulting in lower partial safety factors. The key findings of this study could be beneficial for the structural design of new and lifetime extension of existing marine structures. © 2017 Elsevier Ltd
Subject
2015 Fluid & Solid Mechanics
SR - Structural Reliability
TS - Technical Sciences
Berthing energy
Berthing impact
Berthing load
Berthing velocity
Marine structures
Partial safety factor
Navigation
Ocean currents
Ocean structures
Offshore structures
Structural design
Velocity
Wind effects
Berthing energy
Characteristic value
Design recommendations
Load and resistance factor designs
Safety factor
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TNO identifier
782491
Publisher
Elsevier Ltd
ISSN
0951-8339
Source
Marine Structures, 58, 73-91
Document type
article