Maeslant barrier

Maeslant barrier: Alternative solution for the upgrading of the Maeslant barrier

Riteco, J.

Jonkman, S.N. (mentor)
Molenaar, W.F. (mentor)

Civil Engineering and Geosciences

Hydraulic Engineering

2017-01-16

Additional thesis - The Maeslant barrier was the final piece of the Delta works which protects a large area of the Netherlands. However the present barrier seems to fulfil his function, several Dutch experts have doubts about the system. However the discussion on the Maeslant barrier not being safe enough refers mostly to future scenarios. Experts expect that the barrier already will not provide enough protection from storm surges as of 2070. The goal of this research is to investigate an alternative solution for the upgrading of the existing Maeslant barrier in order to make it more reliable for the future. The two functional requirements that all future solutions must fulfil are assuring enough safety against storm surges and providing enough navigation space for ships. The new waterway has to be accessible at any time during normal conditions. For the hydraulic boundary conditions future water levels are taken into account by implying the most extreme Deltascenario steem. In a variant study four different designs are worked out. Design A introduces a solution with navigation locks. This solution closes of the new waterway entirely which can be an advantage for safety reasons but also a disadvantage in terms of navigation. The second design consist of an inflatable rubber barrier like the Ramspol barrier. The mode of operation and in terms of maintenance the inflatable barrier has a lot of advantages, two of the biggest disadvantages are however the tension forces and stresses in the membrane and the fact that the dimensions exceed the largest inflatable rubber barrier by the triple. Design C consist of a new barrier with tumble gates either hydraulic or pneumatic. This design was already introduced as one of the alternatives for the existing Maeslant barrier. However these kind of gates are straightforward and simple the disadvantage is that large movable parts are placed under water which makes maintenance work laboured and expensive. The last design consists of several rising sector gates as it has already been built at the Thames in the UK. The dimensions would be in the same range and therefore a lot of the experience could be used for the design. This design however leads to fixed structures within the water way which are a hindrance for navigation. The inflatable barrier is worked out in more detail. After taking a closer look at the biggest inflatable barrier in the world, the Ramspol barrier in the Netherlands, working out general information on inflatable barriers provides the basics for the design of the new Maeslant barrier. Because of the positive experience at the Ramspol barrier a combination of water and air was chosen to be the filling material. A purely air filled barrier leads to high tension forces in the membrane that exceed the bearing capacity. By using factors between the crest-height and the base width of the clamping lines and the crest-height and the circumferential length of the membrane based on the Ramspol barrier, the initial parameters for the new Maeslant barrier could be calculated using a crest-height of 22 meters. From that an iterative calculation process using a excel spread sheet calculates the shape, the internal air pressure and tension force in the membrane. First results than lead to an inflatable rubber barrier with a crest-height of 22.55 m, an internal air pressure of 0.6 bar and a tension force of 730 kN/m2. Optimizing the structure leady to a final design with a smaller base width, slightly longer circumferential length, lower tension force and internal air pressure and a higher crestheight. Using the calculated tension force the horizontal and vertical clamping forces are calculated and can be used to design the clamping lines and the foundation. The foundation also includes the bottom recess where the membrane is stored in the deflated situation. The membrane fits exactly over the ribs created by conveyors to facilitate the horizontal transport. The membrane will then be held in place by applying an under-pressure in the membrane.

http://resolver.tudelft.nl/uuid:0d0d0de6-4807-4ae3-8c6f-af92b1cf064b

Student theses

student report

(c) 2017 Riteco, J.