Comparison of Fender Dimensions, PIANC WG211 and PIANC WG33

Abstract: PIANC WG211 was tasked with updating the guidelines for design of marine fender systems. One of the changes to the new guideline is the change in approach to the design. Whilst the load and resistance factor design approach is widely adopted in the design of marine structures, the PIANC WG33 (2002) design guideline utilizes a global safety factor, referred to as the factor for ‘abnormal’ impact. Based on statistical data from recorded berthing velocities, fender manufacturers’ data, and adjustment factors for uncertainties in berthing energy calculation, PIANC WG211 has established partial factors of safety for fender selection. To gain clarity on what the effects from the updated design approach is, this paper compares the outcomes of the old PIANC WG33 and the new PIANC WG211 guideline. Data from actual project fender design specifications have been considered. Given similar input variables the new design method generally results in marginally smaller fender dimensions. However, WG211 references PIANC WG145 (2019) for berthing velocities, which are generally higher compared to Brolsma’s berthing velocity curves in PIANC WG33. This difference can result in quite large fenders in the absence of site-specific information. During this study the higher berthing velocities recommended by PIANC WG211 were confirmed based on new berthing records collected in a port in the northeast part of Europe. In general, when site-specific information is used to evaluate the navigation conditions and the associated berthing velocity, the design method of PIANC WG211 will result in reasonable fender dimensions. In addition, it was found that the fender dimensions can often be optimized based on a parametric analysis of the fender pitch. Consequently, the conclusion is that the new design approach results in reasonable fender dimensions for majority of the ports and terminals around the world. Nevertheless, it is crucial to account for any local experience as well as the influence of the local navigation conditions, such as wind, waves, currents and berthing maneuvers on the berthing velocity, as well as receiving input from the asset owner (e.g., port or terminal authority) regarding the required safety level of the fender system specific to the berth.

How does this project / topic contribute to the advancement of the industry and profession?: This paper will help designers of fender systems to get familiar with the new PIANC WG211 Fender design guideline. The paper explains how fender dimensions can be optimised in order to reach a more sustainable design

Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: Yes, the paper discusses the new safety philosophy for fender design and introduces several new methods such as how to take into account multiple fender contact and site-specific information.

What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: The main challenge was the interpretation of the old PIANC WG33 guideline. To ensure a solid comparison the authors discussed some important input variables, such as berhting velocity, berthing angle, point of berhting impact.

Who is the target audience for this paper?: Port engineers, fender suppliers and manufactures, consultants in port engineering, executives, marine terminal operators.