The floating construction method: A new method of constructing large submerged and floating structures

The floating construction method: A new method of constructing large submerged and floating structures

Hendriksen, R.

Vrijling, J.K. (mentor)
Molenaar, W.F. (mentor)
Peperkamp, W.J.M. (mentor)

Civil Engineering and Geosciences

Hydraulic Engineering

2011-12-08

Parking problems in cities become more significant every day. Parking tariffs are going through the roof and parking spaces are limited. Therefore, cities are researching alternatives for parking on ground level and underground. One of these alternatives is parking underwater. One of these cities is Amsterdam. This city ranks number 5 on the list of most expensive cities to park in Europe. To create more parking spaces, the city of Amsterdam is researching the possibility of parking garages underwater at several locations. One of these locations is the Oosterdok near the central train station. A feasibility in 2009 study showed that a parking garage underwater with 350 parking spaces and constructed with the traditional construction method is not financially feasible. [Oosterdok, 2009] This situation is used to determine whether or not a new construction method could be the solution, namely the floating construction method. With this construction method, the structure is constructed directly on the water. The base consist out of a floor of EPS and concrete. This floor floats and makes it possible to construct the rest of the structure on top. This process is shown in the figure below. The advantage is the fact that an expensive temporary construction pit isn’t needed, which normally forms 20 to 30% of the total construction costs! The floating floor consist of the patented Flexbase system and is shown in the figure below. It starts with constructing a 800mm thick EPS floor consisting of 4 layers of glass fibre reinforced EPS250. Directly on top of this EPS floor the concrete floor is poured. When this floor is hardened the formwork, consisting of EPS60 blocks, for the beam grid is placed. When the beam grid is poured and hardened, the second and last floor is constructed to end up with a floating sandwich structure. The parking garage is constructed directly on top of the Flexbase floor. The parking garage has two floors and 750 parking spaces. It is 129 meters long, 76 meters wide and 6,5 meters high. This does not include the 2,05 meter thick Flexbase floor. When the garage is finished, it still floats and has a draught of 6,05 meters. When the garage element is completed, it is immersed. Ballast tanks are placed inside the element and filled with water. When the element is at the desired depth and level, grout anchors are drilled through the floor to keep the element immersed. The ballast tanks are emptied and the garage element is coupled to the entrances for cars and pedestrians. The entrances are constructed separately. Conclusions The floating construction method is technically and financially feasible for this situation. The floating construction method is approximately 11,5% cheaper than the traditional construction method. When the benefits come exclusively from parking fees, the floating construction method becomes financially feasible for this situation with hourly parking tariffs of €2,16. This research shows that the floating construction method could be a better and cheaper alternative for traditional construction methods.

Floating Structure
Floating
Construction method
Flexbase

http://resolver.tudelft.nl/uuid:10518aa6-82eb-4d6a-959f-6417d8033246

2011-12-19

Student theses

master thesis

(c) 2011 Hendriksen, R.