METHOD FOR INSTALLING A LOAD-BEARING CIVIL ENGINEERING CONSTRUCTION

Abstract: The invention relates to a method for installing a load-bearing civil engineering construction. A set of hollow support elements coupled to one another is installed on a bed, the support elements in a first layer being coupled in the lateral direction and a second layer of support elements coupled in the lateral direction being placed on top of the first layer and joined to the first layer. The support elements preferably comprise containers which are coupled to one another. The support elements are in particular suitable for installation on an underwater bed, in order to extend up to close to or above the water level. By this means watery areas, such as, for example, marshy ground, harbours, coastal regions or lakes can rapidly be temporarily filled in in order to form temporary building, storage or transport sites during construction work. One example of this is a temporary pier in the sea, or a temporary wharf. By means of the method according to the invention it is possible to meet the requirement for greater flexibility of harbour sites and the switch to unloading wharves of shorter lengths and with larger adjoining storage sites.

Description: Method for installing a load-bearing civil engineering construction The application relates to a method for installing a load-bearing civil engineerijt construction, such as foundations for quays, piers, dikes and dams, landing stages, storage sites and road formations. It is known to produce constructions of this type by first excavating the layers of soil of lower strength and then building up to a requisite height with layers of sand. These sand layers first have to settle. Consequently, in order to increase the settling rate an excess depth of sand is frequently temporarily applied. This involves a long wait, usually a number of years. After adequate settling of the sand layers, the construction can be finished, for example by laying a road surface and/or constructing a building. A major disadvantage of this building method is the long time that is needed to complete the construction. With constructions of this type a minimum life which is of the order of 40 to 50 years is assumed. For soil strata of very low strength, such as peat and plastic clay, with which the groundwater level is very close to the surface level, it is known to form the load-bearing construction by burying large float-like polystyrene slabs, onto which the road construction is laid, as a result of which the latter sinks less rapidly, or no longer sinks at all, relative to the groundwater level. The aim of the invention is to provide a method for rapidly and inexpensively forming a load-bearing construction which can be installed either on an underwater bed or on a bed above water, specifically with the aid of strong load-bearing elements of low weight. A reliable life of 20 - 25 years must be achieved with this type of lightweight and at the same time strong constructions. It is preferable that numerous parts of the load- bearing construction can be re-used when the construction is removed. A further aim of the invention is to provide a versatile method with which use can be made of existing techniques and materials, with which the energy consumption is low and which can be employed under many different conditions. A further aim of the invention is to provide a method for rapidly installing a temporary foundation. To this end the method according to the invention is characterised in that a set of hollow support elements coupled to one another is installed as the construction, wherein the support elements are coupled in the lateral direction in a first layer and wherein a second layer of support elements coupled in the lateral direction is placed on the first layer and joined to the first layer. The hollow support elements are lightweight and can easily be transported in large quantities to the destination. By stacking and coupling the elements to one another, a predetermined volume can be built up in a simple manner until the top layer of the support elements is at the desired height. A top layer, with any building, road surface and other infrastructure thereon, can then be laid on the top layer of support elements. Because the support elements coupled to one another are lightweight, the additional load on the substrate due to the support elements is low, so that no major settlement of the substrate occurs. As a result of the modular construction of the foundations, the shape thereof can easily be adapted to the desired circumstances. The support elements are in particular suitable for positioning on an underwater bed so as to extend to close to or above the water level. By this means watery areas, such as, for example, marshy ground, harbours, coastal regions or lakes can be quickly temporarily dammed in order to create temporary building, storage or transport areas during construction work. One example of this is a temporary pier in the sea, or a temporary wharf. With the method according to the invention it is possible to meet the requirement for greater flexibility of harbour sites and the switch to unloading wharves of shorter lengths and with larger adjoining storage sites. The support elements are also suitable for installing on a bed above water, such as in dam, dike or road formations or in dry docks, or other applications. The hollow support elements can be made of metal, plastic or concrete frames, around the corners of which reinforcing elements are fitted in which the coupling elements are able to engage. The outer surfaces of the support elements which are delimited by the ribs of the frames can be open or closed. The containers can be prism-shaped, polygonal or of parallelepiped shape. Preferably, the support elements are formed by containers. These transport containers, which are used for sea and road transport, are provided with coupling elements at their corners and can easily be joined to produce groups or modules with a number of vertically stacked horizontal layers, with various containers in each layer. The containers in a horizontal layer can extend, adjoining one another, in one direction or in two mutually perpendicular directions. When packed together, the coupled containers have a rigid lateral bond and a high load-bearing capacity, combined with a relatively low weight. Preferably, containers rejected for transport are used, so that the method provides for effective re-use of residual material. The uppermost layers of the foundation formed by the stacked containers, which layers can be close to or above the water line, can be used as storage space. Preferably, modules are formed from a number of (for example 5 by 5) containers before the containers are placed on the substrate or on other containers, which containers are brought into position as a unit using a crane, for example by sinking. A frame of taut steel cables can be fitted around the edges of a module of coupled containers and diagonally between the corners, in order to increase the cohesion within a module, whilst, should non-uniform settling take place, the containers within the module retain sufficient freedom of movement to be able to follow the movements. The top layer of support elements is preferably covered by a capping layer, such as, for example, a layer made of a plastic mat (geotextile) with a sand layer on top, in which the services are installed. A pavement surface, such as paving, a concrete or asphalt layer, etc., is laid on top of the sand layer. Using the method according to the present invention, wharves can be formed in an advantageous manner, for example by modifying existing harbours and expanding the storage sites. The wharf is made from a sheet piling wall behind which the stacked support elements form the foundation for the storage site. A supporting beam made of concrete is installed along the top of the sheet piling wall, the front rail of the wharf crane being anchored to said supporting beam. One embodiment of the method according the invention will be explained in more detail with reference to the appended drawing. In the drawing: Fig. 1 shows a sectional view of a harbour with an infill made up of containers; Fig. 2 shows a view of a set of containers held together by tensioning cables or rods; Fig. 3 shows a section of a mooring wharf for ships where use is made of containers as the foundation for what is above. Fig. 1 shows a section of a harbour, located between two wharves 1, 2, which according to a first embodiment of the present invention has an infill of hollow support elements 3. In the embodiment shown, the support elements 3 consist of conventional containers, such as are used in container transport by container ship or trailer, which have been coupled to one another in the horizontal and the vertical direction. Coupling of containers to one another takes place by means of the conventional coupling elements 4, 5 close to the corners of the containers. With this arrangement each container is coupled to three neighbouring containers at its corners. After the layer of sludge has been excavated from the water bed, the existing bottom 6 of the harbour is raised by means of a foundation layer 7 of sand, which preferably is of shallow depth, as a result of which settling of this layer remains very slight. This sand layer 7 is levelled horizontally if necessary. The containers 3 coupled to one another bear on this sand layer 7 in a stable manner. Groups of containers are joined to one another by means of tensioning cables 10, 11 so as to form modules 8, 9 of, for example, 5 x 5 containers, which can be handled easily. These modules 8, 9 can be placed on the sand layer 7 or on other containers with the aid of a crane (not shown). Space 13, 12 is left between the modules 8, 9 and between the module and the wharves 1, 2 in order to compensate for any movement of a module as a result of unequal settling of the substrate. A water-permeable plastic layer or plastic mat (geotextile) is first laid on the top of modules 8, 9 of coupled containers. A top layer of concrete capping slabs 14, 15 is laid on top of the water-permeable plastic layer or mat as the foundation for a pavement surface to be laid. Capping slabs 18 fitting tightly between the modules are used to produce the joint between the container modules to prevent material from the top layer or sand layer 16 being able to get between the containers. Services, such as electrical cables, water pipes and telecommunication cables, can be installed in the sand layer 16 on top. Fig. 2 shows a module 19 according to the present invention. In the embodiment shown, the module 19 comprises a set of eighteen containers, preferably used containers, which have been joined to one another in the conventional manner. The containers are provided with coupling elements 21 at all their corner points. Said coupling elements are preferably of the same type as the reinforced holes made in the corners of conventional containers. All containers are joined in both the horizontal and the vertical direction to the adjoining container within a module. In order to keep the containers in a module 19 better together, the module is provided with both horizontal, vertical and diagonal tensioning cables 22, 23, 24 which extend between the corners 25, 26, 27, 28, 29, 30 and 31 of the module 19. These tensioning cables 22, 23, 24, attached to the outside of the module in the embodiment, make it possible to lift the module as a whole and to move it with the aid of a crane. A module of 5 x 5 containers can be moved by a 150 tonne crane. In this embodiment, containers 20 which are positioned below or close to the water line are provided with holes 32 in the flat sides so that water is freely able to flow into the containers during sinking. Containers which end up in or below the (sea) water level are protected against the corrosive action of water and oxygen, for example by means of an epoxy primer with a bitumen layer on top. The tensioning cables or rods are provided with combined protection consisting of, for example, a PNC casing with a layer of grease beneath it. Fig. 3 shows an embodiment according to the present invention where the containers 33 coupled together form the foundation for a mooring wharf 34 for ships 35. The tops of the containers 33 are covered by a layer of geotextile 39 with a sand layer 39' on top of this. The sand layer 39' is preferably approximately two metres thick and is intended to distribute the forces which act at ground level over the uppermost containers. On the water side of the wharf 34 the containers are protected by a vertical sheet piling wall 36, the purpose of which is to prevent the containers being exposed to substantial forces as a consequence of ships 35 docking in the harbour. The sheet piling wall 36 extends into the clay layer 38, located below the bottom sand layer 37, in order to prevent a flow of water between and below the containers 33. A supporting beam 40, for example made of concrete, is installed on top of the sheet piling wall 36. The top of the supporting beam 40 makes it possible to install harbour furniture, for example a bollard or a crane rail 41. Installing a second crane rail on the top of the sand layer 39' is one of the possibilities, by means of which transfer of goods becomes possible. Using the method according to the invention, time savings of 1.5 to 2.5 years can be achieved when filling in harbours. The low inherent weight, together with the bottom sand layer, does not exceed the bearing ratio of the underlying bed, so that pre-stressing is not required. According to the invention, filling in a harbour site can take place in five phases: 1. Prepare the harbour for filling in (both the harbour bed and the existing wharf walls); in some cases this includes installing the removable wharf wall. 2. Prepare (coat, reinforce the roofs and perforate), couple and form modules from the containers. 3. Position container modules (from the shore onto a pontoon and from the pontoon into the water). 4. Make up the site (lay capping slabs and top layer, install retaining walls, guide walls and other harbour furniture and foundations for the superstructure). 5. Equip new site (cables and piping, pavement surfaces and access roads). The superstructure can also be produced using containers. A further few additional layers can be placed on top of the uppermost foundation layer of containers. The top container can, for example, serve as offices or as a warehouse. The container underneath can be used for storage. Lighting pylons can be installed in foundations on four adjoining comer points of individual containers. An additional plate, located over said four comers, ensures a uniformly distributed load over the four containers.

Claims: Claims 1. Method for installing a load-bearing civil engineering construction on a bed, characterised in that a set of hollow support elements coupled to one another is installed as the constmction, wherein the support elements are coupled in the lateral direction in a first layer and wherein a second layer of support elements coupled in the lateral direction is placed on the first layer and joined to the first layer. 2. Method according to Claim 1 , characterised in that the support elements are in the form of a frame and are of prism shape, polygonal or parallelepiped shape constmction and are provided with coupling elements close to comer points. 3. Method according to Claim 1 or 2, characterised in that the hollow support elements comprise containers. 4. Method according to one of the preceding claims, characterised in that the containers are installed on an underwater bed and are perforated prior to installation. 5. Method according to Claim 2, 3 or 4, characterised in that each coupling element of a support element is connected to the coupling element of at least one, preferably at least two, support elements adjoining the support element concerned. 6. Method according to one of the preceding claims, characterised in that groups of support elements are formed by stacking a number of layers of support elements coupled in the lateral direction on top of one another and joining them to one another, which group is installed on the bed or on other support elements using a crane. 7. Method according to Claim 6, characterised in that the support elements in the group define comer points, peripheral edges located between the comer points and outer surfaces, the support elements being joined by tensioning elements which extend along the peripheral edges as well as between the comers, diagonally over the outer surfaces of the group. 8. Method according to one of the preceding claims, characterised in that the upper layer of support elements is covered by a top layer. 9. Method according to Claim 8, characterised in that the top layer comprises a sand layer. 10. Method according to Claim 9, characterised in that a layer of slabs coupled to one another or a plastic reinforcing mat is installed beneath the sand layer. 11. Method according to one of the preceding claims, characterised in that a wharf is formed from the stacked support elements by installing a water-retaining sheet piling wall and stacking the support elements against the sheet piling wall. 12. Method according to Claim 11, characterised in that a concrete reinforcing layer is laid over a top edge of the sheet piling wall, on which reinforcing layer a rail for a wharf crane is fixed. 13. Method according to one of the preceding claims, characterised in that at least the support elements close to the water surface are provided with a corrosion-resistant coating.

Inventors: VAN T ZELFDE WILLEM DAVID ANTH, VAN 'T ZELFDE, WILLEM, DAVID, ANTHONY
Applicants: HOLLANDSCHE BETONGROEP NV, T ZELFDE WILLEM DAVID ANTHONY, HOLLANDSCHE BETON GROEP N.V., VAN 'T ZELFDE, WILLEM, DAVID, ANTHONY
Application year: 2000
Main classification: E02D27
IPC codes: E02B3, E02D23, E02D27