Backgrounds partial energy factors for fender design

PIANC WG211 was tasked with updating the design approach of marine fender systems. While the load-andresistance- factor design approach is widely adopted in the design of marine structures, the PIANC WG33 design guideline utilizes a global safety factor, referred to as the factor for ‘abnormal’ impact. However, it is unclear whether this global safety factor results in an appropriate reliability level. Several aspects of fender system design that significantly influence the fender reliability level do not appear to have been considered by PIANC WG33, such as, reliability targets, the effect of vessel berthing frequency and multiple fender contact. This paper explores the use of statistical data from recorded berthing velocities, fender manufacturer’s data, and other adjustment factors, to establish suggested partial factors of safety for the selection of fenders. The proposed partial energy factors are intended to provide the industry with greater uniformity in the assessment of the reliability level of fender systems and clearer guidance on the recommended design approach than is presently provided. Furthermore, this method can also be used in conjunction with national codes and standards. It is hoped that port authorities and terminal operators may also be able to use the findings of this study to derive greater insight into the reliability of their own fender systems and to optimize service