The Gevelco quay wall

Abstract

In this thesis, an investigation is described to the measured horizontal displacements of a quay wall in the Port of Rotterdam. This quay wall was built in 2003 to replace an existing jetty. A combined tubular wall was installed and some of the concrete jetty piles were reused as foundation piles for the relieving platform. Anchorage for the quay wall is provided by an eight meter high continuous anchor wall, 38 meter behind the quay wall made of steel sheet piles. The connection between the two walls consists of high strength steel presetressed strands. Prior to describing the actual research in this report, measurements are considered that have been carried out over time on top of the quay wall. These measurements indicate that horizontal displacements increase nonlinearly in time. This trend was the reason for an investigation to all possible causes of the horizontal displacements of the combi wall. In this thesis, the research is discussed and possible causes of the measurements are revealed by considering one representative cross section of the largest part of the quay wall. The main part of this thesis deals with the investigation for possible causes of the measurements and is elaborated by considering the different influences for the representative cross section. Firstly, time dependent soil behaviour is examined. The Koppejan formula and the finite element method are used to determine the influences of consolidation and creep. Due to counteracting prestressing and gravity forces the effects in time due to consolidation and creep seems to be negligible. Secondly, the capacity of the anchor wall is investigated based on Coulomb’s theory and the finite element method. Due to a proven densification of the passive soil wedge, the capacity appeared to be sufficient. Subsequently, macro stability of the soil body between the anchor and combined wall (Kranz stability) is considered. Stability is proven to be sufficient by performing a hand calculation for the drained and undrained situation, followed by a verification calculation with a program based on the sub grade reaction method. Another considered possible cause is the difference in interpretation of the soil profile used in this report and the one used in the design. Therefore, a parametric study for the soil parameters is performed with the sub grade reaction method. These calculations show that the design profile resulted in larger deformations than a soil profile with expected values. Furthermore, it was decided to investigate the influence of the position and magnitude of a surcharge load. When the design load of 50kN/m2 is applied near the anchor wall, it was concluded from calculations that horizontal displacements are almost equal to the measurements. When a higher load is applied at positions further away from the anchor wall, again horizontal displacements appeared to be close to the measured displacements. Both the position and magnitude of loading are described as possible explanations for the measured deformations. Finally, it is concluded that saving money in the design stage by applying an anchor wall, resulted in more deformations than expected and made them dependent on the position of loading. Additionally, it is concluded that applying a higher load than was agreed upon in the terms of reference, resulted in more deformations than expected as well.