Comparative analysis of design recommendations for quay walls

Abstract

The design and construction of quay walls is a problem in which people are interested for ages. There are many methods and recommendations developed for this topic. They differ for each country and type of structure and are developed for local conditions. Some of these methods and recommendations are collected in a national code, which can be used for the design of maritime structures. In Europe they try to normalize all national codes to obtain one European standard. Each of the European members can add their national parameters to this code. For the normalization of codes it is interesting to investigate which codes are available and which methods are used in the national codes. In this analysis are the difference between design guidelines for quay walls considered, with special attention to the safety analysis and design process, to find an overview of design results. Therefore first a global analysis of contents is carried out. This results in 4 guidelines with a clear safety approach, also adapted to the latest design philosophies: CUR 166 and Handbook Quay Walls (both Dutch), EAU 2004 (German), Eurocode 7 (European Union). The last one is not used, because it is still under construction and includes mainly the safety approaches treated in the other 3 guidelines. For CUR 166, Handbook Quay Walls and EAU 2004 comparative calculations are carried out in a beam on elastic foundation model. Two cases are considered which are very typical for quay walls in the Port of Rotterdam: a quay wall with 12 m retaining height and a quay wall with 30 m retaining height (this one includes a superstructure). First, for all guidelines the characteristic parameters are determined: water levels, geotechnical properties and external loads. The geometrical aspects and material parameters are kept the same for the analysis. The safety approach in the guidelines give the greatest difference in the design process. If a fault tree is present, the failure mechanism can be overviewed, which is very useful for design calculations. Mainly the application of safety factors on actions or action effects lead to different answers. The CUR 166 applies safety factors on soil strength parameters (actions), the Handbook Quay walls and EAU 2004 applies the safety factors on action effects (internal forces). The EAU 2004 gives in all calculations the smallest bending moments and anchor forces for the application in a beam on elastic foundation program. This is mainly due to the higher strength of the soil properties in the EAU 2004 and due to the fact that the Blum schematization does not satisfy in the beam on elastic foundation program. For the calculation of case 1 (retaining height 12 m) the Handbook Quay Walls gives higher bending moments than CUR 166, mainly due to the application of a special load combination with extreme scour. For the calculations of case 2 (retaining height 30 m) the CUR 166 gives higher bending moments than Handbook Quay Walls. This is mainly due to the application of the relieving platform in combination with safety factors on the soil strength parameters, which results in higher bending moments. It can be concluded that the EAU 2004 is not useful for application in a beam on elastic foundation program. The CUR 166 and Handbook Quay Walls are very useful for a beam on elastic foundation method. Mainly the Handbook Quay Walls is very specialized on quay walls structures. It includes certain load combinations, descriptions for the calculation of a superstructure and applies partial safety factors on action effects. This makes the Handbook Quay Walls more useful for the design of quay wall structures than CUR 166.