Influence of quay wall defects on the structural response

Abstract

Inner–city quay walls fulfil a number of very important functions where the retention of water is the most important one observed from a structural perspective. Despite their importance, not all of these structures are very well maintained, especially the older ones. Each municipality has their own maintenance regime, depending on the allocated budget. Deficient quay wall management of a few municipalities in the Netherlands resulted already in several quay wall failures, but there are also a lot of those structures still in a good condition. The differences in quay wall compositions and internal force transfer mechanisms could be one of the reasons why some structures do not show signs of deterioration where others are in a very deteriorated state. This hypothesis is the starting point for the following research question: “What is the influence of structural deficiencies to the overall strength and stability of a wooden foundation system under a quay wall structure?”. The geotechnical and material resistances of the quay wall elements are used as a basis for the study to the influence of quay wall defects on the internal force transfer mechanisms. Five quay wall structures with different geometries in Rotterdam and The Hague are selected for the structural calculations. With the help of assessment reports, a few common defects are chosen which are likely to occur for these kind of structures. First, the displacements and internal forces of the pile cap beam in the middle cross-section are calculated when the structure shows no signs of structural declination. The obtained results are then compared with the same base quantities where one of the structural defects is applied. In this way, the effect of each defect can be determined. Although there are large differences between the composition of the various quay wall structures, a general conclusion can be drawn from the performed calculations. A larger number of piles under a quay wall structure has a positive influence on the redistribution of internal forces from a weakened spot to an unaffected part of the structure.