The present invention relates to a composite structure fabrication method as set forth in claim 1 for various building components.

The use of composite structures is known as such since combinations of a profile plate and concrete serve to pro¬ duce preferable composite structures, wherein a generally steel-made profile plate serves as a component more re¬ sistant to tensile stresses and concrete, in turn, serves primarily as a structural component taking up compressive forces. This type of composite structures have been described e.g. in Patent publications GB 1 469 478, DE 24 13 645 and DE 22 52 988. A profile plate often serves as a mould for casting concrete mass thereon. The cited DE publications propose to improve the adhesion or gripping between a profile plate and concrete by means of corrugations which are directed from a profile plate to concrete and can be perforated, expanded, bent aside or buckled.

Our earlier Patent application FI 894085 has described a method for the fabrication of a composite structure as a combination of a profile plate, generally a steel profile plate and concrete by spraying concrete onto the profile plate.

One of the drawbacks encountered in the prior known fabrication methods for composite structures is that a profile plate is not sufficiently strong to serve as a casting mould under fresh concrete mass without extra supports. The gripping between a profile plate and concrete is generally incomplete. The strengthening effect of a reinforcement is restricted on a narrow

zone adjacent to the surface of a profile plate. The gripping shapes of the plates are inconvenient to produce or are ineffective in practice.

An object of this invention is to alleviate the above drawbacks and this is accomplished with a method of the invention by assembling a profile plate from two or more superimposed plate elements which are nested one within the other at the corrugations and shaped into the attachment with each other.

The equipment intended for carrying out a method of the invention is subsequently described in the claims.

A large number of various embodiments can be found for the invention. The accompanying drawings are only intended to serve as an example and to illustrate the practical working of the invention.

Fig. 1 shows one composite plate structure of the invention with plate elements separated.

Fig. 2 shows a section along the line 11-11 in fig. 1 with the plate elements nested within each other at the corrugations.

Fig. 3 shows the section of fig. 2 after shaping the plate element fast to each other.

Fig. 4 shows one composite plate structure of the invention in a plan view.

Fig. 5 shows a section along the line V-V in fig. 4 prior to nesting the plate elements within each other at the corrugations.

Fig. 6 shows a detailed view of one composite structure of the invention.

Fig. 7 shows one possible section along tne line VI I-VI I in fig. 6 prior to the addition of concrete mass.

Fig. 8 shows one alternative section along the line VI I- VI I in fig. 6 after the partial addition of concrete mass .

Fig. 9 shows a section of one composite structure of the invention, the structure being provided with cavities between flat surfaces.

Fig. 10 shows one cellular upright structure of the invention.

Fig. 11 shows a detailed view of one bridge embodiment of the invention.

Fig. 12 shows one possible horizontal section along the 1 ine XI I -XI I in fig. 11.

Fig. 13 shows a cross-section of one bridge embodiment of the invention.

Fig. 14 shows a detailed view of one horizontal structure of the invention.

Fig. 15 shows a detailed view of another cellular upright structure of the invention.

The essential purpose of this invention is to provide a composite structure between concrete and steel as effectively as possible. If desired, a method of the

invention can also be applied to produce thin and strong monocoque structures and cellular structures having a great flexural rigidity even prior to the addition of concrete. This facilitates the making of moulds and span dimensions can be substantially increased. By dividing the tension-receiving steel profile plate into a plurality of sub-elements, the loading can be distributed over a larger area in a reinforced concrete structure for thus improving the strength and durability of the structure in varying load conditions.

Fig. 1 shows in principle the elements of one profile plate structure prior to securing the components to each other. On the top there is a so-called expanded metal sheet 10 which is produced by cutting from a thin sheet and which is laterally extended to form mesh apertures 90. During the elongation some of the mesh strands 10a may turn to a position deviating from the plane of elongation i.e. twist even to a position perpendicular to the main plane of the mesh. This is beneficial in view of the adhesion of concrete mass, e.g. in shotcreting or casting. The expanded metal sheet 10 includes uncut thin sheet sections 17 which are bent to form a corrugation 49 deviating from the general direction of mesh 10. Inside this corrugation 49 is formed a recess 44 which is capable of accomodating wholly or partially a corrugation 39 made in an intact profile plate 1 therebelow. Inside this corrugation 39 is formed a recess 14 which is capable of accomodating wholly or partially a corrugation 139 made in a expanded metal sheet 110 therebelow. Furthermore, a recess 144 formed by the uncut section 117 of the bottom expanded metal sheet 110 can be used to accommodate a corrugation of another component positioned further below etc. The expanded metal sheet 110 shown furthest in the bottom can be provided with similar apertures 190 to those

in the expanded metal sheet shown on the top, which promotes the adhesion of concrete.

Fig. 2 shows the assembly of fig. 1 in a section after fitting the corrugations inside the recesses. In this case, an expanded metal sheet 10 and an expanded metal sheet 110 are positioned to be fast to the surface of a profile plate 1. By varying the heights of corrugations and recesses it is possible to provide assemblies with separating spaces between profile plate 1 and expanded metal sheets 10 and 110.

Fig. 3 shows the same section as fig. 2 after shaping the corrugations stuck to each other. In this case, the shaping is down by pressing corrugations 49, 39, 139 with a force 55 in a manner that the corrugations of various plate components 10, 1, 110 are laterally extended for side extensions 22. If the pressing is continued sufficiently, a portion 30 parallel to the profile plate may be formed on the top surface. In order to prevent the one-sided lateral buckling, during the action of a downward force 55 it is possible to apply laterally supporting forces 56 which contribute to the creation of side extensions 22. This way is produced a joint assembly 32 consisting of various plate elements 10, 1, 110 and binding the various plate components firmly to each other. If desired, forces 55 and 56 can be utilized by making therefor a manually operated tool e.g. for construction site conditions. This could be e.g. a pneumatic hammer- type device for joining together e.g. adjacent profile plates. The joining together of plate components can also be effected by means of another type of deformation of the nested corrugations, such as. one-sided pressing, tilting, lateral bulging, cutting etc.

Fig. 4 shows in a plan view one composite plate structure of the invention. On the top there is an expanded metal sheet 10 which includes uncut portions 17. These uncut plate portions 17 have a great tensile strength in the direction of an arrow 16. On the other hand, in the direction perpendicular thereto, the expanded metal sheet is stretched or elongated for providing apertures 90 and, in this direction, mesh 10 does not have much tensile strength. In order to take advantage of the tensile strength of an expanded metal sheet the structure should be positioned in a manner that the main tensile stresses are in direction 16. Visible underneath said expanded metal sheet 10 is a piece of an intact profile plate 1. The figure does not show a second expanded metal sheet possibly lying underneath said profile plate 1.

Fig. 5 shows a section along the line V-V in fig. 4 prior to nesting corrugations 49, 39, 139 within each other. In this case, expanded metal sheets 10 and 110 are placed on both sides of an intact profile plate 1. The corrugations 49 of an upper expanded metal sheet 10 are provided with small side foldings 72 for facilitating the lateral spreading. Similar side foldings can also be made on the corrugations of plates 1 and 110. If necessary, the side foldings 72 can be made in different plates on different levels and in different sizes.

Fig. 6 shows in a perspective view one composite structure of the invention, wherein joint profiles 32 are horizontal parallel to the profiles of a plate 1. On top of a profile plate 1 and a mesh 10 is sprayed a rather thin layer of concrete 6. which, upon setting, gives the structure such a strength that heavier concrete mass 99 can be cast without special support systems. Side extensions 22 and mesh 10 together serve to hold the

concrete firmly secured to a profile plate 1 in a manner that its tensile strength can be fully utilized. The joint profiles 32 can also be made on different levels, if desired. As seen from the side, a surface 30 can e.g. corrugate in vertical direction, whereby the width of side extensions 22 may vary. Thus, the plate elements cannot move relative to each other. If desired, the structure can be prestressed by drawing profile plate 1 and mesh 10 in the direction of the shaped profiles during casting, the steels 10 and 1 subsequently creating in concrete 6 and 99 a compressive force for increasing its strength. Particularly the shapes of expanded metal sheet 10 make the prestressing possible as steel is not able to slide relative to concrete.

Fig. 7 shows one possible section along the line VI I-VI I in fig. 6 prior to concreting. Between a joint profile 32 and plate elements 1 and 10 forms after the concreting a pillar-shaped compression zone 77, wherein the concrete through its compressive strength retains the plate structure firmly in concrete mass.

Fig. 8 shows an alternative section along the line VI I-VI I in fig. 6. In this case, the corrugations of plate elements 1 and 10 are dimensioned to leave a space 36 between the extensive portions of the plate elements. Through the apertures of expanded metal sheet 10 concrete 6 can also fill this space 36 for building a pillar-like compression zone 77 therein the same way as below a joint profile 32. By placing an expanded metal sheet 10 further away from profile plate 1 the stresses can be distributed over a larger area in concrete mass 6. In the case of fig. 8, there is an empty space 35 inside the joint pro¬ file 32. It may have formed by not wishing to extend the side extensions 22 quite to the extreme width.

Fig. 9 illustrates an embodiment, wherein a profile plate 1 is secured between two flat profile plates 111. The structure is made rigid by securing plates 1, 111 and 10 by means of joint profiles 32 to form a single unit. It is possible to fabricate such rigid plate assemblies at a plant and to coat them with concrete 6 only at a construction site e.g. by spraying. Also the fabrication of the entire structure at.an element manufacturing plant is possible. The structure shown in fig. 9 may be e.g. a horizontal section through the wall of a building, a support wall or some other vertical structure. Cavities 92 can serve as an insulation layer against heat or noise. If desired, cavities 92 can be filled with blow wool or some other insulant. The structure of fig. 9 can also be a vertical section e.g. through the intermediate or upper floor of a building or some other horizontal structure. It is also possible to make a concrete layer 6 just on one side of plate structure 1, 111, 10. A mesh 10 holds con¬ crete 6 securely to plate structure 1, 111, 10. Said mesh 10 is secured by means of joint profiles 32 firmly to the plate structure. If desired, the structure of fig. 9 can also be made floatable in water by closing the open ends of the cavities. Hence, this type of structure can be e.g. a segment of a bridge which is floated to the site of installation. For floating, the relative proportion of cavities 92 can be increased considerably.

Fig. 10 shows a plate structure, wherein profile plates 1 are fitted in a cellular configuration. This way the number of cavities exceeds considerably that produced in the case of fig. 9. This increases the structural rigid¬ ity substantially e.g. for the purposes of a support wall. The insulating ability of the structure is also improved as the number of cavities increases. A concrete layer 6 can also be provided on both sides of the plate structure

1 , 1 0

Fig. 11 illustrates one bridge embodiment of the invention at the installation stage as the internal plate surface 1 of a bridge opening 93 is being coated with shotcreting. The question can be e.g. about a rim bridge for pedestrian and bicycle traffic or a culvert for the passage of water. The shaped profiles of profile plate 1 are arranged in the direction of the cross-section for giving the structure as much rigidity as possible in that direction against various loads. In principle, fig. 11 can also depict a large subway for vehicle traffic. The same way it is even possible to build a tunnel-shaped noise barrier over a traffic route.

Fig. 12 shows a horizontal section along the line X I I -X I I in fig. 11. This illustrates more clearly the valley regions 2 of a profile plate 1, in which a concrete spray 4 most readily penetrates. A concrete mass supply pipe 5 is shown in principle. Prior to coating the inside it is preferable to shotcrete the outside of a structure with a concrete layer 8 before an external loading is added to the structure. The rim and culvert structures are primarily subjected to loads of compressive forces, so the concrete layers 6 and 8 are especially capable of taking up these stresses. In a conventional corrugated tube culvert, which is made of steel sheet, all stresses must be received on steel plates. Thus, the thickness of steel sheet becomes great and increases the costs. In the embodiment of the invention, the profile plate can be very thin indeed and, hence, it is inexpensive. During the spraying operation, for example, it is possible to place under the concrete layers some various devices, such as electric cables or other wires 68 so that they will be hidden below the finished structure. The final surface

can be made e.g. flat 9. In view of securing the concrete layers 6, 8 coated on different sides, it is preferable to employ meshes 10 fixed by means of a joint profile 32 on both sides of profile plate 1.

Fig. 13 shows in principle one bridge cross-section of the invention. A profile plate 1 shaped as a bridge-bearing structure, e.g. a box beam, is first coated on the inside e.g. with a shotcrete layer 6 for increased strength. After this layer 6 is set, a profile plate 1 above the box is fitted crosswise in position. At the same time it is possible to effect the reinforcement of the top section by means of an external shotcrete layer 88. After this is set, a bridge deck 80 can be cast by using e.g. cast concrete 99. Finally, the outside of the bottom section can be coated with a shotcrete layer 8. Between the outside surface layers 88 and 8 may remain a construction joint 87. If desired, it is possible to provide the bridge structure with upright strut means also in the middle of the box.

Fig. 14 shows an embodiment similar to that of fig. 9. The plate structure is however assembled by using a plurality of plate elements 1 in view of building a rigid cellular or honeybomb-shaped structure e.g. for floors or other horizontal structures which require a great rigidity even before shotcreting. In the case of fig. 14, the bottom surface of the structure is also coated with a shotcrete layer 8 e.g. for eliminating fire hazards. Cavities 92 can be filled with desired materials.

Fig. 15 shows an embodiment similar to that of fig. 14. In order to provide additional rigidity, some of the cavities 92 are also coated on the inside with e.g. a shotcrete layer 8. The adjoining of adjacent plate ele-

ments into a plate element of larger area can preferably be effected by using corrugations similar to those for joining plate elements on top of each other. Thus, the corrugated joint of adjacent plate elements serves several different purposes, namely to join adjacent and super¬ imposed plate elements together and, in addition, to provide a gripping means for concrete.

At least one plate element 1 of those plate elements making up a profile plate is impervious to concrete. It can be completely intact (no apertures) or it may include sm ll holes which do not allow the passage of cast or sprayed concrete.

The plate element assemblies can be manufactured e.g. at a rolling mill plant by applying rolling techniques prior to the transport to a construction site.

In addition to profile plates, it is of course possible to employ also extra reinforcements, such as reinforcement bars 50 shown in fig. 13.