Dike reinforcement City of Tiel
| Client | FPH Ploegmakers, on behalf of Waterschap Rivierenland |
| Completion time | 2022 – 2024 |
| Market | Water safety |
| Team | |
| In collaboration with | FPH Ploegmakers B.V. |
| Location | Tiel |
| Project scope | 2,6 km |
| Expertises | |
Dike reinforcement city of Tiel requires innovative engineering
The dike reinforcement consists of a combination of closures, sheet pile walls, earthworks, and a filtration technique. This project benefits greatly from ABT’s extensive experience with dike reinforcements. Colleagues from the geotechnical and infrastructure disciplines collaborated to develop an integrated and feasible design.
CSM walls protect history
In this project, new applications are used at various times and locations. For example, CSM walls have been applied in the primary flood defenses near the historic building of Grand Café Bellevue. This technique is not often used. CSM stands for ‘Cutter Soil Mixing’, which means that the soil is mixed with a cement mixture. In this mixture, steel profiles, which provide the strength of the wall, are suspended at the correct height. Unlike the installation of regular sheet pile walls, this technique does not cause vibrations. Ideal for a historic location. Extensive calculations and coordination with FPH Ploegmakers, subcontractor Bodembouw, and client WSRL were required to achieve an optimal result.
Challenging sheet pile wall construction
There is also the use of a special sheet pile wall construction. This is anchored in the ground with a double row of grout anchors. These anchors prevent the sheet pile wall from leaning too far forward due to the difference in ground level on either side of the wall. To distribute the concentrated forces from the anchors along the length of the sheet pile wall, a so-called waler construction has been applied, consisting of two walers placed one above the other. These have been modeled and calculated in a 3D model to check the balance, deformations, and forces in the waler construction. Additionally, various detailed calculations have been made for the connections between the grout anchors, walers, and sheet pile walls.
An additional challenge involved the yet-to-be-built apartment complex. Therefore, the foundation piles were first installed and measured to create the final anchors based on the as-built position of the sheet pile wall.
The right-angle corner in the sheet pile wall construction, combined with the large retaining height of over 10 meters, posed an extra structural challenge for this section. To prevent the tie rods from crossing each other, six so-called leg anchors were placed horizontally across the corner.
Anti-piping construction
In the dike section near the Amsterdam-Rhine Canal, there is also something special. An innovative filtration technique, known as the coarse sand barrier, has been applied in this section to prevent piping. Piping occurs when water flows under the dike, carrying sand with it and thereby weakening the dike. If the flow increases, the dike can even collapse. One of the solutions to this is the coarse sand barrier. This stops the formation of the erosion channel at the barrier. Groundwater can pass through it, but fine sand is held back.
Coupures
The coupures in this project consist of new and renovated concrete or masonry structures that create a gap in the dike, allowing both slow and fast traffic to cross the dike at ground level. The existing coupures (both masonry and concrete) have been fitted with a new concrete floor beam and anchor plates embedded in the walls at the top for attaching temporary cross planks during high water. This ensures that these coupures are high enough for the expected higher water levels in the future. The new coupures are entirely made of concrete and constructed directly at the correct height.
During high water, the coupures are closed with large stacked cross planks to protect the city behind the dike from high water. Afterwards, the planks can be removed, and traffic can pass through the opening again.
Current status
The project will be completed in 2024; the final concrete work on the openings will take place this summer. The dike reinforcement in the City of Tiel is part of the Flood Protection Program (HWBP).
Images © HWBP
Dyke reinforcement Heel and Beesel
Dyke reinforcement Heel and Beesel
Dyke reinforcement Sterke Lekdijk
Dyke reinforcement Sterke Lekdijk
