Shielding effect of piles on quay walls

Shielding effect of piles on quay walls

Galema, A.

Jonkman, S.N. (mentor)
De Gijt, J.G. (mentor)
Bakker, K.J. (mentor)
Everts, H.J. (mentor)

Civil Engineering and Geosciences

Hydraulic Engineering

Hydraulic Structures and Flood Risk

2013-12-12

This thesis has as subject the shielding effect of piles on the front wall of quay walls. The reason for writing this paper is to find an answer to the difference between field measurements and design calculations of stresses and deflections in the front wall of a special type of quay wall in the Port of Rotterdam. The relevance of this issue concerns the optimization of a quay wall with relieving structure to investigate the behavior of this construction and possibly to reduce costs. Focus is on the behavior of prefabricated concrete bearing piles and MV-pile anchors below relieving structures. This thesis has been prepared for obtaining the degree Master of Science in Civil Engineering at the Technical University in Delft. The purpose of this research is to analyze and quantify the shielding effect of piles on the front retaining wall of quay walls. From measurements on the extension works for the EKOM quay wall in the Port of Rotterdam it can be concluded that the design calculations and field measurements do not comply. The calculated maximum front wall deflections are higher than the measured values and also the maximum calculated bending moments in the front retaining wall are higher than measured. These findings have been used in the design of a more recent quay wall project in the Amazonehaven by applying bending moment reduction factors for the front retaining wall. This research focusses on how the prefabricated concrete bearing piles and MV-pile anchors contribute to lower deformations and bending moments in the front retaining wall. For this research a literature study is conducted to determine the design aspects of an existing quay wall in the Amazonehaven in the Port of Rotterdam. Furthermore the recommendations of the handbook Quay Walls, design guidelines for horizontally loaded piles, behavior of arc forces in soils and recommendations for shell factors in soils have been studied. For the research an analytical method based on Van IJsseldijk - Loof and Begemann – De Leeuw and also a finite element method (FEM) using Plaxis 2D have been applied. The results of the analytical method have resulted in an initial input on the shielding effect of piles on the front retaining wall of quay walls. The method makes use of simplified models and ground data. Horizontal soil stress reductions near the combi-wall over the Holocene soil layers of 20% is considered maximum feasible. The method based on FEM is prepared to make a comparison with the analytical method and to use sophisticated models and soil data for more details. The comparison shows that the horizontal soil stress reductions near the combi-wall corresponds well, but that the bending moments and pile wall deflections differ between both methods. The conclusions reached with the FEM method has led to a shielding effect of the piles on the maximum field bending moments in the combi-wall of 13%. The MV-pile anchors have a small to negligible influence on the shielding effect. As conclusion it can be said that for the design of quay walls with relieving structures the shielding effect of piles on the front retaining wall is part of the design. Reductions of 13% are achievable according to the FEM analysis. It is advised to design quay walls with relieving structures with FEM. This provides a better picture of how relieving structures work and the shielding effect of piles can be modeled in more detail. It is also recommended to conduct more field research to determine the shielding effects for different quay walls designs.

quay walls
relieving effect
shielding effect
Finite Element Method
plaxis

http://resolver.tudelft.nl/uuid:79773063-b9c8-40fa-bae4-abef7a019836

Student theses

master thesis

(c) 2013 Galema, A.