Floating structure consisting of a number of assembled self-floating elements and method for constructing the floating structure.

The present invention concerns a floating structure consisting of a number of assembled self floating elements and method for constructing the floating structure.

More specifically the invention concerns an assembly of a floating structure for example a larger dock for maintenance of oil tankers for example. The floating structure is constructed by a number of self-floating elements which are assembled while floating.

The self floating elements and the method for fabricating the floating structure are adapted to be utilized in connection with limited water depth and fabrication facilities with limited space, which requires that the structure must be light and assembled of elements requiring small draft. The element assembly must be carried out in the water in floating condition. Further, it must be a safe and strong connection between the elements taking care of the global bending and shear forces that can arise during use.

Due to the limitation with regard to water depth and fabrication facility, such structure will not be constructed by concrete elements which will require a larger water depth.

A corresponding structure of steel will normally require subsea welding. One of the objects of the present invention is to eliminate subsea welding and thereby reduce the cost and fabrication time.

Further, it is an object of the present invention that the single elements can be constructed in a dimension which permits that they can be transported on channels and rivers, and than could be assembled in a area of the sea with very limited draft.

The objects of the present invention is achieved by a floating structure consisting of a number of assembled self floating elements, preferably made by steel, characterized in that each floating element has a double floor and double sidewalls at each end to be connected to another element, extending a distance inwards the element and closed by an internal bulkhead.

Parallel duct channels are routed within the double floor and double outer walls, extending from the end of the element, i.e. coupling surface with another element, to the internal bulkhead.

The space within the double bottom and the double sidewalls, outside the duct channels, is filled with a material tolerating pressure, preferably concrete.

After connecting two elements tension cables or bolts are provided within the duct channels of two adjacent elements in order to fix the connection between the elements, whereby the duct channels after assembly and tensioning of tension cables etc. are filled with injected concrete. Preferred embodiments of the floating structure are further stated in the claims 2-9.

The objectives of the present invention is further achieved by a method for assembling a floating structure consisting of a number of assembled self floating elements, preferably of steel, wherein each floating element is in its lower area for assembling with another element is provided with a double bottom and double sidewalls extending a distance inwards the element, pipe channels are provided in parallel and with mutual distance within the cavity of the double bottom and the sidewalls and extending from the inner termination surface of the cavity and perpendicular to its outer termination, i.e. coupling surface with another element, the floating element in its lower ends and on the outer walls in its couplings area with another element provided with hook devices for receiving complementary bolt devices provided on the other element, characterized in that a first floating element is deballasted with even keel, a second floating element is trimmed, deballasted at its bolt device coupling end, the hook device coupling end of the second floating element is pulled towards the bolt device-coupling end of the first floating element whereby the hook- and bolt devices are connected in that the second element is deballasted down to stable contact between the elements is achieved, the second element is deballasted until the first and second elements upper part/top plates are brought together whereafter the top plates are connected, preferably by welding, the second element is deballasted again whereby pressure is applied on a gasket in the lower assembling (connecting) area for the elements,

lid which closes the pipe channels in the lower connecting area of the first and the second floating element is removed and tension cables, bolts etc. are installed in the pipe channels, and every cavity between the first and the second element is injected with concrete whereafter the tension cables, bolts etc. are tighten up and concrete is injected in the pipe channels.

The present invention will be further explained with reference to the attached drawings, wherein:

Fig. 1 shows a floating structure, seen from the cross end, according to the present invention,

Fig. 2 shows the floating structure in the length wise direction consisting of seven assembled self floating elements,

Fig. 3 shows one of the elements in figure 2,

Fig. 4 shows a detail of the element's coupling face with another element, Fig. 5 shows a detail of the elements assembling area,

Fig. 6 shows a corresponding detail of another element which is designed for assembling with the element in figure 5,

Fig. 7 shows a detail of a hook- and bolt device for assembling two self floating elements, Fig. 8 is a perspective drawing which particularly shows the coupling face of an element,

Fig. 9 is a detail drawing showing the coupling face to another element, which is meant to be coupled to the element in fig. 8,

Fig. 10 is a perspective drawing showing an end element in a first floating structure part, and

Fig. 11 is a perspective drawing showing a complementary end element of another floating structure part, which is meant to be coupled to the first floating structure main part with an articulated coupling for a flexible way to utilize each main part alone or together. With reference to fig. 1 a cross end of a floating structure 1 or one of a self floating element's 2 external termination i.e. coupling face 11 with another element is shown. As evident from the figure the floating element 2 is in its lower area for assembling with another element 3 provided with a double bottom 5 and double sidewalls 7, extending a distance, for example 2-3 meter, inwards the

element from each end. A cavity 9 which is build up by double steel plates is then created and the cavity 9 is in this embodiment filled with concrete 20. In order to achieve adherence between the concrete 20 and steel shear ribs 22 are welded on the inside of the steel plates as shown for example in fig. 4 and 5. Pipe channels 17 of steel, extending from the inner termination surface 10 of the cavity and perpendicular to its external termination/coupling face 11 , is casted in the concrete 20 with end lids 18 for temporary closing of the pipe channels 17. As shown at fig. 4 and 9 the concrete end surface, i.e. the coupling face with another element has a recess 12 for mounting of a gasket 13 along the entire bottom 5 as well as up along the outer sidewalls 7.

With the object to steer (guide) and connect the self floating element 2, 3 hook devices 24 and bolt devices 26 are provided on the lower ends of each element's 2, 3 outer wall 8, as shown for example at fig. 8 and 9.

With reference to fig. 5 an element is shown with a vertical extending recess 14 along the two sidewalls of the element in the coupling area for receiving a complementary elevation 15 on another element shown at figure 6. Fig. 10 shows a self floating element which in this embodiment is an end element in a first floating structure part 29 and which further in its first end is provided with a flexible hinge coupling 30 in the form of a number of brackets 32 with bolt openings 32 provided on the coupling surface of the bottom for receiving a complementary horizontal displaceable bolt structure 36 with bolt 37 provided on a complementary end element to another floating structure main part 35 shown in fig. 11.

Fig. 10 depicts a self floating element which in this embodiment is an end element in a first floating structure part 29 and which further in its one end is provided with a flexible hinge coupling 30 in the form of a number of brackets 32 with bolt openings 33 provided on the coupling surface of the bottom for receiving a complementary horizontal displaceable bolt structure 36 provided on a complementary end element of the second floating structure main part 35 shown in fig. 11.

The invention shall now be further explained in connection with a method for assembling the floating structure 1 according to the invention. A first self floating element 2 is transported to an assembling site where it is deballasted with even keel . A second self floating element 3 is transported close to the first

element 2 and trimmed, deballasted at its coupling end which is provided with bolt devices 26. The elements 3 opposite the coupling end which is provided with hook devices 24 is pulled towards the bolt device end of the element 2. The hook devices 24 are then coupled together with the bolt devices 26 as the element 2 is deballasted. When fixed contact is established the bolt end of the element 3 will be deballasted in order to bring the top plates 6 of the element 2 and element 3 together whereafter these are welded together in order to achieve a fixed connection. After the top plates 6 are connected the element 3 is deballasted again in order to apply pressure on the gasket 13. Lids 18 which close the pipe channels can now be opened and short tension cables (or tension bolts) 21 can now be installed. Each cavity between the elements 2, 3 are injected with concrete prior to post-tensioning of the tension cables 21 in order to ensure full strength through the bottom section of the floating structure 1. After the tension cables 21 are tensioned the pipe channels are injected with concrete 23.