EP1718820A1

EP1718820A1 - Structure for modular prefabricated poured concrete forms

Info

Publication number: EP1718820A1
Application number: EP04804970A
Authority: EP
Inventors: Rubens Pasotti
Original assignee: Ilpa Industria Legno Pasotti Srl
Current assignee: Ilpa Industria Legno Pasotti Srl
Priority date: 2003-12-23
Filing date: 2004-12-21
Publication date: 2006-11-08
Anticipated expiration: 2024-12-21
Also published as: EP1718820B1; WO2005064099A1; ITSV20030051A1

Abstract

A structure for modular prefabricated poured concrete forms for making vertical walls, comprising a frame made of at least two studs or joists (2, 2’, 2’’) for supporting at least one panel (3) or a plurality of adjacent panels (3), which studs or joists (2, 2’, 2’’) are at such a distance from each other that each panel (3) has at least two opposite edges abutting against said two studs or joists (2, 2’, 2’’), and each abutting edge of each panel (3) has a stepped cross section (203) and the surface of each stud or joist (2, 2’, 2’’) against which a panel edge abuts has a complementary stepped cross section (202’, 202’’), so that the edge of the panel (3) is fully superimposed on the side of the stud or joist (2, 2’, 2’’) against which it abuts. Each abutting edge has a stepped cross section which is integral with the panel or is made by a strip consisting in a pre-shaped element (5) which is secured to the panel peripheral edges by means of adhesive of by chemical/physical bonding. The invention may be also used for making prefabricated vertical and/or horizontal walls, columns and/or pillars, as well as prefabricated shelters or enclosures, that may be wholly or partly closed or partly open, or like vaults, tunnels or the like. Also a method for building a modular prefabricated wall particularly for a form for poured concrete is provided.

Description

I PA I DUSTRIA EGNO PASOTTI S.r.l,

Structure for modular prefabricated poured concrete forms for making vertical walls, horizontal walls such as ceilings, slabs or the like and columns or pillars

The invention relates to a structure for modular prefabricated poured concrete forms for making vertical walls, horizontal walls such as ceilings, slabs or the like, and columns or pillars, comprising a frame made of at least two studs or joists adapted to support at least one panel or a plurality of adjacent panels, which studs or joists are at such a distance from each other that each panel has at least two opposite end edges abutting against said two studs or joists and each abutting edge of each panel has a stepped cross section, whereas the surface of each stud or joist against which a panel edge abuts has a complementary stepped cross section. Structures of the this type are known, which are widely used in building, particularly for making forms or formworks, which are in turn used for making vertical and/or horizontal and/or inclined walls, such as floors, ceilings, slabs or the like, made of concrete. These structures are typically made of a plurality of studs or joists, generally made of elongate box-like steel elements, which are disposed in parallel and/or crossed arrangement and at a predetermined distance from each other so to form a frame in which a plurality of adjacent panels are mounted in order to form a poured concrete retaining wall. These structures generally have the advantage that they may be disassembled and reused. Due to obvious aesthetic reasons, it is desirable that the face of said retaining wall in contact with concrete is substantially continuous and flat, therefore the studs or joists have stepped panel supporting surfaces having a depth substantially corresponds to the panel thickness, when seen in a direction orthogonal to the surface of each panel, as shown in greater detail in the description of the drawings. Nevertheless, due to unavoidable tolerances encountered in the mutual positioning of panels and studs/joists, gaps may occur between panels and studs/joists, which may cause concrete leakage or marks or impressions to be formed on the wall surface. These marks/impressions may be provided by the impression of the metal stud or joist, of the gap that may occur between the stud/joist and the panel and possibly of the panel itself, that may deform due to moisture. In order to at least partly protect the panels or the plates making part thereof this panels or plates are coated with a waterproofing material such as layers of platic materials and/or of paint. Generally the core layer of the panels is made by wood or similar materials such as chipboards or the like. The current state of the art comprises different kinds of combinations of panels, plates and stud or joists for building such walls. Two different kind of structures can be mainly differentiated one for building vertical or essentially vertical walls and the other for building horizontal or essentially horizontal walls. Relating to the structures for building vertical walls according to one known structure, panels are known which are formed by plates mainly of wood or with a core layer or with a supporting layer of wood which are then mounted in the frames build by the parallel and crossed studs or joists. The plates are laid with the side at the edges opposed to the side facing the concrete against the studs or joists. Gaps between adjacent panels are then filled or closed with pasty material such as silicone rubber or the like. Ttiis operation is done by hand and has several drawback . First of all this operation is time consuming and tlαus costy. Furthermore the peripheral sides of the plates, i.e. the thickness sides are not optimally sealed against penetration of fluids and gases and particularly of water. So the water contained in the liquid concrete and which is subjected to a high pressure can easily reach the panels and penetrate it from the edges. As a further drawback silicone rubber may not fill completely the gaps for their entire depths and has also a very high compressibility. When such a silicone rubber filled gap is subjected to the high pressure of the poured concrete then it is compressed below the surface of the panel facing the concrete so that grooves or channels are formed between the adjacent panels ad the gaps which produce marks on the finished walls . Relating to this effect it has to be considered that a panel having 1350mm width and 2^*700 mm length and conceived for a pressure of about 60 kN/m²' commonly requested by the building industry is subjected to a load of about 22 tons. The penetration of water at the gaps not perfectly sealed by the silicone rubber fillings due to non perfect sealing causes damages of the plates . Penetration of water causes particularly severe damages with panels in which plates are provided which are layered with plastic material or with a water tight layer at one or both surfaces, since the water impregnating the panel cannot evaporate through the two faces of the panel but only through the very limited surfaces along the edges of the plate. Furthermore if the plates are not taken away from the frame the silicone rubber filling further prevents the drying of the plate. So perfectly sealing the panels or the plates at their edges is one of the most important objects in panels having surfaces which are protected against water by water tight sheetings or layers. Horizontal structures are known which uses slim and small panels having a good sealing at the edges . This kind of panels are supported by props and the edges of the latter directly adhere against the edges of the adjacent panels. Also, these panels shall be relatively narrow to support the weight of the poured concrete. Therefore, there is a relatively great number of joints between panels, hence of possible resulting marks on the concrete cast for making the horizontal wall. Document US 3,137,909 discloses a structure of the above mentioned kind. As it will appear from the following this panel has also several drawbacks consisting in the fact that the plate is badly secured in the frame, no good sealing of the edges of the plate or of the panel can be obtained and the compensation of the dimensional tolerances between the plate or panel and the frame is very limited. The panels according to US 3,137,909 are made of so called plywood and are mounted inside a metallic frame by means of filler or adapter strips having an L shaped cross section. This filler or adapter strips are secured to the frame sides by means of an adhesive and fits in a complementary seat of the frame sides thereby overlapping the edges of the frame sides facing the concrete. The shaped filler strips are flush with the surface of the plywood plate with the wing of the L shape superimposing over the said front side of the frame in order to avoid gaps or the like . The plywood plate is pressed in place inside the frame which is provided with the filler or adapter strips fixed to the frame sides . This has the drawback that during pressing of the panel inside the frame provided with the filler or adapter strips, the filler or adapter strip is compressed by the edges of the panel in a non controllable manner. So it is possible that due to the compression in a direction parallel to the surface of the panel or perpendicular to the peripheral edges of the panel the filler strips are also subject to a compression in a direction perpendicular to the surface of the plate or parallel to the peripheral edges. When this happens, the filler strip being of elastic and compressible material will be reduced in its thickness in a direction perpendicular to the surface of the plate and the surface of the panel adjacent to the concrete will present some steps due to the difference of the thickness of the plate and of the filler or adapter strip caused by the compression of the said strip. Furthermore the strip are only mechanically compressed against the edges of the plywood plate or panel and does not provide for a water tight connection between the peripheral edges of the plywood plate and the filler or adapter strip. The exposure to penetration of water is increased considering the danger of the forming of steps between the strip and the plated edges due to compression of the said strips when the panel is forced in place in the frame provided with the said strips . In this case the strip will not cover the entire thickness of the panel edges forming the above mentioned step and leaving free to water penetration a part of the thickness of the edges of the panel or plate. This is particularly relevant if one considers that edge sealing is one of the most important topics of the panels to which the present invention refers which are have a layered structure, both faces of the panel being layered with a water proof sheet of platic material or paint or the like as disclosed above. A further drawback of the panel according to US 3,137,909 lies in the fact that the filler strips can only have a limited elastic compressibility and thus this strips can compensate only very narrow dimensional tolerances between the frame and the panel or plates . Indeed providing strips with a high compressibility would allow the compensation of higher dimensional tolerances between the frame and the plates or panels but on the other hand the strips would also be compressed by the fluid concrete thus forming grooves or depressions which result in marks in the finished wall . Due to penetration of water or increased exposure to humidity at the peripheral edges the plate can be subjected to swelling in thickness . The risks in a material degradation and particularly in swelling are higher at the edges which can become thicker than the rest of the plate causing again irregular surfaces of the finished concrete walls . Furthermore material degradation at the edges can cause breaking off of pieces of the plate at the peripheral edges particularly when the panels has to be used again and mounted in a new frame thus preventing the panle or plate to be used again.. For the above reasons the mounting of the said known panels in the frames requests every time at least a control that this mounting has succeeded and that no step or gap has been formed between the plates the filler strips and the frames . If some of these defects is discovered an intervention by hand is necessary for manually filling gaps or eliminating steps with other materials such as silicone rubber. In any case a perfect protection or sealing of the plate peripheral edges from the penetration of water of humidity can only be achieved by providing a sealing with sealing materials as for example the above mentioned silicone rubber or other sealants . This further steps request many hour of work and have an high impact on the costs . A further drawback which is common to all panels cited above suited for building vertical walls of forms for pured concrete consist in the fact that the peripheral edges of the panels are not protected against mechanical damaging when the said panels or plates are not mounted in the frames . This is also particularly important if one consider the particular use to which the panels or plates are destined. Therefore the present invention has the object of improving a structure as described at the beginning in such a way that in combination with achieving a perfect adherence between panels and studs or joists, so as to obtain a substantially smooth concrete cast, anyway free of the conventional unaesthetic marks or impressions left by prior art structures or wherein such marks or impressions are considerably reduced also a perfect sealing of the panels at the edges is obtained in a simple and relatively non expensive way. A further object of the present invention consist in the fact that without giving up the above mentioned object a balanced and symmetric fitting of the panel or plate in the frame is achieved which allows compensation of high tolerances relatively to the dimension and the shape of the frame and of the plate or the panel without incurring in the formation of marks in the finished concrete wall . Still another object of the present invention is to allow mounting and securing the panels or the plates to the frame in a simple, rapid and inexpensive way. The invention achieves the above purposes by providing that each abutting edge having a stepped cross section is integral with the panel or is made by a strip which is secured to the panel peripheral edges by means of adhesive of by chemical/physical bonding. With chemical physical bonding any kind of bonding is meant such as soldering or thermal adhesion or the like as typically occurs by bonding plastic materials . Advantageously the bonding of the abutting edges to the peripheral edges of the panels are such that a water sealing effect is obtained at the interface between the abutting edges and the peripheral edges of the panel. According to a further feature the abutting edges are made of compressible material such as rubber or rubber like plastic material or any kind of plastic material which has compressible elastic behavior. Preferably the abutting edges are formed by polyurethanes and particularly by polyurethanes obtained from the co-polymerization of polyols with iso-cyanates . The said polyurethanes can be molded either by casting at low pressure or by high pressure injection in order to obtain the strips forming the abutting edges according to the present invention. In order to adjust the hardness and other mechanical properties and to stabilize the dimensions of the molded strips by reducing internal tensions during injection and also in order to reduce costs the polyurethanes can be also charged with inorganic charge materials . According to a further embodiment of the present invention, the panel is a laminated panel having at least two layers, one of which is a cover layer of plastic material, included thermoplastic fibers, and the other is a supporting layer of other materials such as for example wood or the like. In this case the strips forming the abutting edges are bonded at least to the cover layer of the panel by means of chemical/physical bonding forming a water tight junction between the said cover layer of the panel and the strips forming the abutting edges . The said trips forming the abutting edges may also be bonded to the peripheral edges of the supporting layer. When the supporting layer is of wood or the like a direct bonding can be obtained between the strips forming the abutting edges and the corresponding peripheral edge of the wooden supporting layer or and adhesive layer can be provided between the adhering faces of the strip forming the abutting edges and the peripheral edge of the panel . According to a preferred embodiment, the panel is made of at least one supporting layer made of at least one layer of wooden material and which supporting layer is covered on both of the opposing surfaces by a cover layer of plastic material bonded thereto, the strip of plastic material forming the abutting edges being bond to the peripheral edges of the panel by chemical/physical bonding with at least each one of the peripheral edges of the cover layers and/or also with the peripheral edge of the supporting layer. Also in this case the bonding of the strips forming the abutting edges of the panel are bonded with a water tight junction at least with the two cover layers of the panel . It is important to stress out that in this case, the panel provided with the stepped abutting edges integral with the panel itself or bonded thereto solves several of the drawbacks of the known panels . Further to this the fact of providing the said abutting edges integral with or bonded to the panel protects the peripheral edges of the panels against ruptures and allow a very simple handling and mounting of the panels in the supporting frames. Indeed the panels according to the present invention can be simply pressed inside a frame formed at least by two opposite studs or joists or by four stud or joists. The strong bonding of the abutting edges to the panel plate provide for the fact that the abutting edges are always flush with the surface of the panel plate. The junctions between the strips forming the abutting edges and the panel plate are water tight and any further manual work can be avoided. As a further improvement, being the strips which form the abutting edges made of elastic compressible material the panels can be at least provisionally or also definitively retained in position within the frames by simply pressing them inside the frame due to the compression forces acting perpendicularly to the peripheral edges of the panel plate and generated by the compression of the elastic or compressible abutting edges . According to a further improvement of the present invention, the stepped abutting edges of the panel and the complementary stepped surfaces of the studs or joists of the frame against which the said stepped abutting edges of the panels abut has each one a surface which is essentially parallel or slightly inclined relatively to the surface of the panel and a surface which is essentially transversal or perpendicular to the surface of the panel. This definition being equivalent to the one considering the direction of pressing the panel in the frame, namely the said stepped abutting edges of the panel and the said complementary stepped surfaces of the studs or joists of the frame against which the said stepped abutting edges of the panels abut has each one a surface which is essentially parallel or slightly inclined relatively to the direction of pressing the panel in the frame and a surface which is essentially transversal or perpendicular to the surface the said direction of pressing the panel into the frame. In this case at least the surface of the abutting edges which is essentially transversal or perpendicular to the surface of the panel or which is essentially parallel or slightly inclined relatively to the direction of pressing the panel in the frame has at least one or more continuous projection or lip which is compressed and deformed against the corresponding surface of the stepped studs or joists of the frame when the panel together with the abutting edges is pressed into the frame . When more panels are mounted in adjacent frames, the stepped abutting edges are shaped in such a way that the external peripheral edges of the said abutting edges of adjacent panels adheres one to the other the surfaces of the said abutting edges parallel to the surface of the panel and oriented against the concrete, i.e. opposite to the frame being flush one with the other and flush with the corresponding surface of the panels . Analyzing the behavior of the panel in use and under the stress determined by the concrete it has been discovered that there are contrasting effects which may influence the calibration of the compressibility of the abutting edges. On one side the said abutting edges has to be compressible in a sufficient measure in order to allow that the panels can be pressed and retained inside the frame. On the other end the abutting edges are also subjected to the pressure exercised by the concrete in the form so that a high compressibility would determine that the concrete would compress the stepped abutting edges . Thus considering that the panel plate is not compressible, the concrete would form a depression along the abutting edges which would result in projecting marks or stripes from the surface of the finished concrete wall once the form has been taken away. Thus the calibration of a correct hardness and/or compressibility of the strips forming the butting edges is of importance if it is requested that the finished concrete wall is perfectly plane and regular. According to experiments carried out by the applicant using strips of polyurethane with a hardness between 90 and 100 shore A and/or between 39 and 55 shore D the mechanical behavior of the strips forming the abutting edges satisfies every of the above functions of the said butting edges as disclosed above, namely the abutting edges allow the mounting of the panels in the frame by pressing simply the panels in the frame, ensures a water tight adhesion to the frame, the peripheral edges of the abutting edges of adjacent panels adhere one against the other without forming gaps, the said abutting edges provide for compensation of dimensional tolerances between the panels and the frame due to their construction or to thermal expansion or to expansion determined by swelling of the plates and the said abutting edges has sufficient dimensional stability not to be compressed by the concrete in a way that determines marks on the finished walls and also that the mechanical resistance of the abutting edges of the panels protects the peripheral edges of the panel from being mechanically damaged during handling. The compensation of high dimensional tolerances between the panels or plates and the frame and the fact that the abutting edges has to stand the high pressures of the liquid concrete in order not to be compressed causing marks on the finished wall are contrasting needs . On one hand in order to compensate high tolerances the abutting edges must have a very high compressibility on the other hand the said abutting edge must not be highly compressible since then the pressure of the poured concrete will generate depressions which will lead to marks on the finished wall. Thus according to a further feature of the present invention the abutting edges are made in such a way as to show different compressibility in a direction perpendicular to the syrface of the panel and in a direction parallel to the surface of the panel. According to a first embodiment, the said different compressibility behavior is achieved by providing at least the surface of the abutting edges which is essentially transversal or perpendicular to the surface of the panel or which is essentially parallel or slightly inclined relatively to the direction of pressing the panel in the frame with at least one or more continuous projections or lips or with at least one row of discontinuous or dot or spot like separated and spaced apart projections or lips which are compressed and deformed against the corresponding surface of the stepped studs or joists of the frame when the panel together with the abutting edges is pressed into the frame itself. The said projection elements can be spot or dot like elements or elongated elements extending over a certain part of the length of the profiled element forming the abutting edges of the panel or plate. The said projections or lips can be provided of the same material of the abutting edges of the panel and provide for a different compressibility in a direction parallel to the surface of the panel due to their shape and dimension. The said projections or lips can be also made of a different material which has a different elastic compressibility. In the first case the projections or lips can be provided together with the profiled elements forming the abutting edges of the panel, such as by injection or extrusion or adhesion. In the first and in the second case the said projections can also be formed by co-injection or co- extrusion by injecting the said projections or lips on an already shaped profiled element put in the mold. According to a further feature the said abutting edges can be formed by a profiled elongated element provided in combination with separated projection elements or lips mechanical means being provided for securing the said projection elements or lips to the said elongated profiled elements . The said mechanical means for securing the said projection elements or lips are preferably removable securing means which allow the said projection or lips to be taken away and substituted with other element or lips . Particularly advantageous for allowing the compensation not only of dimensional differences between the panel or plate and the frame is the fact that a series of differently dimensioned projection elements can be provided. In this case each differently dimensioned projection element or lips has a different thickness in the direction of protrusion form the surface of the profiled element to which they have to be secured. A preferred embodiment provides for projection elements or lips having a toothed securing pin which carries a projection head being made of compressible material, while holes are provided at predetermined positions on the profiled element in which the toothed securing pin can be removably engaged by elastic forcing the said securing pins in the said holes . The toothed securing pin is preferably made or relatively rigid material such as plastic material as polypropylene or the like. In this case the projection elements can be made by co-injection or the like. Alternatively the projecting elements can show an elongated shape extending for at least a part of the length of the profiled element forming the abutting edge of the panel. A supporting strip of rigid plastic material has one or more toothed securing pins at certain intervals one form the other while the strip carries one or more projection heads aligned along its length or a continuous projection element extending for at least part or for the entire length of the said supporting strip. On the profiled element forming an abutting edge of a panel there can be fixes a certain number of the said dot or spot like projecting elements in combination with one or more elongated projection elements . The term toothed securing pin indicates various possible pins having not a smooth surface. Particualelry suitable pins are the ones used in the automotive industry for fixing lining interior panels or other lining sheets to the doors and or ceiling or to other parts of then bodywork of a vehicle. According to the invention the structure panel allows to be superimposed on the side of the stud or joist against which it abuts, and prevents said stud or joist from contacting the poured concrete thereby avoiding the formation of the resulting mark. Futher more a perfect sealing of the panes1 at the peripheral edges can be achieved and the at the same time the invention provides for the capability of compensating high dimensional and shape or positioning differences between the frame and the panel, avoiding without the risks of generating depressions at the abutting edges of the panels and thus marks on the finished walls . The terms stud or joist, as used in this description, shall not be intended restrictively, but shall mean longitudinal elements for supporting prefabricated walls having any orientation whatsoever, for instance a vertical, horizontal or inclined orientation. In combination with the above mentioned features, the studs or joists that form the frame may advantageously be boxlike weight-reducing tubular elements, and have any design whatsoever. Particularly, they may have a rectilinear design and be arranged on the same plane, more particularly parallel to each other. On the other hand, the panels may have any size and shape whatsoever, and be equal to or different from each other. Particularly they may all have the same rectangular shape. Alternatively, sets of panels may be provided, so that the panels within each set are identical in shape and/or size, and the panels of a set are different in shape and size from the panels of the other sets . The frame may be typically formed by at least three studs or joists, i.e. two at the ends and one in the middle. These studs or joists may be arranged in such a manner as to support two parallel rows of adjacent panels, each of which panels has a stepped edge abutting against an end stud or joist, whereas the opposite stepped edge of each panel abuts against the intermediate stud or joist. This intermediate stud or joist may advantageously have two opposed abutment surfaces, each having a stepped cross section complementary to the corresponding abutting stepped panel edge. In this embodiment, only two opposite terminal edges of the panels, abut against only two studs . The intermediate stud or joist may have a center longitudinal ridge on the panel abutment side, whose width is substantially twice the depth of each of the two stepped edges of the two opposite panels, as seen in a direction parallel to the surface of each panel. Thanks to this arrangement, the two facing surfaces of the two stepped edges of the two opposite panels are in contact with each other and the stud or joist is completely covered on the side against which said two abutting edges of the two panels abut . The characteristics of this first embodiment allow to eliminate the gaps between the panels and the stud or joist and, thanks to the fact that the stud or joist is fully covered by the stepped abutting edges of the panels, marks and impressions formed in the wall by the stud or joist are avoided or considerably reduced. In particular instances, a single minimal gap may remain between the two mutually facing portions of the stepped edges of the panels, to be filled with silicone or the like, with considerable time and cost savings. In accordance with a highly advantageous improvement, the intermediate stud or joist may be formed by two parts that are longitudinally separated along a median plane substantially perpendicular to the surface of the panels . The center longitudinal ridge is divided into two halves, each of which is has a width substantially corresponding to the depth of the stepped abutting edges of the two opposite panels, as seen in a direction parallel to the surface of the panels . According to a further improvement, each of the two end studs or joists may be substantially identical to each half of the intermediate stud, which may be formed by coupling two end studs disposed in mirror arrangement, i.e. with the stepped abutment surfaces turned against each other. Hence, the structure is formed by a plurality of equal studs or joists, and thereby provides considerable advantages in terms of construction and modularity. Obviously, means may be provided for removable fastening two end studs or joists in such a manner as to form the intermediate stud. Many other variants are possible and are mentioned in the following: The complementary stepped edges of each stud or joist and each panel may have any design whatsoever, for instance a rounded or polygonal design. According to a preferred embodiment, they have a complementary rectangular shape. The opposite stepped abutting edges of each panel may be formed at the same time as the panel, for instance during panel molding and/or pressing, wherein the stepped edges are provided in the mold design. Alternatively, these stepped edges may be formed at a later time, particularly by removal of material, effected by milling or the like. The panels may be composed of a single element, made of a substantially homogeneous material, such as solid wood, particle boards or plastic. Alternatively, the panels may be composed of multiple modular members, such as wood blocks or the like, which are assembled together along a single plane and/or different planes by gluing or the like. According to an improvement, the panels may have at least one outer coating layer, on one or both faces, preferably with waterproofing properties, for instance made of plastic, included termoplatic fibres, and/or paint . Otherwise, the panels may be of the multilayer laminated type and have at least one intermediate layer which may be itself composed of multiple layers and/or one or more modular members and/or materials, e.g. of a weight—reducing or honeycomb foam, and at least one outer waterproofing coating layer for at least one of the two faces, preferably for both faces. This outer layer may be itself made of multiple layers and/or one or more materials, particularly plastic or paint. The opposite stepped abutting edges of the panels may be made of elements that are manufactured separately from the panels, for instance pre-shaped profiled elements to be attached to the two opposite edges of the panels, for e.g. by nailing and/or screw driving, and/or physico-chemical bonding, for instance gluing or even by injection. These profiled elements which form the stepped abutting edges of the panels may be made of one or more materials, different from the materials of the panel. Depending on the material of the panel, alternatively, they may be made of the same material as that of at least one layer or part of the panel. Advantageously, the waterproofing layers that coat the two faces of the panels may also extend in the areas of the two opposite stepped abutting edges and possibly even to the other two edges. As is known, the peripheral edge is generally the most exposed portion of panels. By this arrangement, panels are fully waterproofed, and this extends their life and enhances their dimensional stability. In accordance with a very advantageous embodiment, that will be depicted in greater detail in the description of the drawings, the strip forming the abutting edges consist in pre-shaped profiled elements made of plastic, particularly polypropylene and/or polyurethane, and be attached to two opposite edges of each panel by physico-chemical bonding or injection, or gluing. Also, panels may have both faces coated with a layer, also made of plastic, particularly wood filled polypropylene, also known as Woodstock®, which is sealingly attached to the stepped pre-shaped edge upon gluing of the latter. The mutually bonded facing surfaces of the pre- shaped profiled element as well as the panel edge itself may have a flat shape. Alternatively, these surfaces may have one or more continuous or discontinuous complementary ridges or grooves on or in the panel edge and on or in the facing edge of the pre- shaped profiled elements which form the stepped abutting edges . These ridges or grooves are in mutual engagement to increase the contact surface and provide a better anchorage, possibly by mechanical forcing, between the step profiled edge and the panel edge. When two opposite panels are laid on the intermediate stud, the mutually facing projecting portions of the stepped edges of the two panels come in contact with and slightly compress each other, thereby filling any gap between the two edges, possibly caused, as mentioned above, by panel positioning tolerances or the like. This arrangement fulfils the object of the invention, i.e. to fabricate concrete walls that are totally free of marks or impressions left by the form structure or in which these marks or impressions are considerably reduced. In a variant embodiment of the invention, the frame may be composed of a plurality of studs or joists oriented in a first direction and a plurality of crossbars oriented in a direction transverse to the former. These studs or joists and these crossbars separate each panel from the adjacent panel/s along the pairs of edges that extend in the two directions transverse to each other. Here, each panel may have stepped abutting edges of one of the above mentioned types on at least four sides or on all of the sides . Advantageously, the crossbars may be made in the same manner as the studs or joists described hereinbefore, whereas the mutually facing edges of the panels of the same row may have stepped edges for abutment against the stepped edges of the crossbars, which may be also made in the same manner as described above . Alternatively, the frame may be only composed of a plurality of studs or joists extending in a first direction, the adjacent panels of each row of panels between two studs or joists being fastened together directly along direct contact edges of the adjacent panels of each row of panels . Here, the facing direct contact edges between two adjacent panels of the same row may have complementary interlocking, wedging or similar profiles . Otherwise, they may be made in the same manner as the stepped panel edges designed for abutment against the studs or joists. Referring to the manufacture of poured concrete shells for horizontal and/or inclined walls, such as ceilings, slabs, floors or the like, the structure of the invention not only improves the aspect of marks on the concrete cast at the contact edges between panels, but also reduces the number of such contact areas because the structure has a higher load bearing capacity and allows to use larger and/or wider panels . The invention may be not only used for the construction of concrete forms for making several different structural elements of building constructions, the combination of joists, studs, crossbars, and panels according to the invention may be advantageously used to make prefabricated walls. Here, the panels may be provided on one side only and/or on both sides of the bearing frame, thereby forming two finishing walls with a perfectly finished exposed face, which two walls are formed by individual panels, with the joists, crossbars, studs or the like being interposed between the two walls, and forming not only the bearing structure but also wall spacing members, to create an air gap there between. This air gap may be a housing for technical systems, such as electrical and/or hydraulic systems, or the like. A further advantageous application may be the construction of prefabricated building structures in which the combination of the bearing frame and the panel as described herein is used to form the outside walls of said structure. In this case, the use of the structure of the invention allows quick and on-site assembly of prefabricated building structures and is particularly advantageous for the construction of shelters or enclosures for civil protection purposes or in building yards . These shelters or enclosures may be totally closed or at least partly open structures or vaults like tunnels or the like. Generally, and particularly in said particular application of the combination of the bearing frame and panels, the panel of the invention provides considerable advantages . By reducing the number of joints, water- and wind- tightness is achieved more simply. The soft or resilient nature of the contact edges between panels makes a tight joint in itself, the edges having a gasket-like sealing effect. Also, by providing that the metal frame is externally covered by the panel edge, the metal part of the structure, which has a higher heat conductivity, is prevented from coming in contact with the outside environment, whereby heat dissipation areas are avoided and thermal insulation of the structure is enhanced. The present invention provides also for a method for building a modular prefabricated wall particularly for a form for poured concrete which methods comprises the following steps: a) Providing a frame made of at least two studs or joists adapted to support at least one panel or a plurality of adjacent panels, which studs or joists are at such a distance from each other that each panel has at least two opposite end edges abutting against said two studs or joists; b) providing each abutting edge of each panel of elastic compressible material and with a stepped cross section; c) providing the surface of each stud or joist against which a panel edge abuts with a complementary stepped cross section; d) inserting the panel in the frame the panel being retained in position within the frame by the said abutting edges; According to the invention, each abutting edge of the panel is made integer or bonded stably to the corresponding peripheral edges of the panel and the panel is pressed together with the abutting edges integrated on it or bonded to it into the frame. The present invention is directed also to a panel for building modular walls or the like having at least one layer and at least one edge which has a steped or L shaped cross-section, the said stepped or L shaped edge being stably secired to the edge of the panel. Further characteristics and improvements will form the subject of the dependent claims . The characteristics of the invention and the advantages derived therefrom will be more apparent from the following detailed description of the annexed drawings, in which: Fig. 1 is a sectional view of a portion of a prior art structure . Fig. 2 is a sectional view of a portion of a preferred embodiment of a structure according to this invention. Fig. 3 is a view of a detail of fig. 2, showing the portion of a panel that abuts against a stud or joist. Fig. 4 is a front view of a structure of the invention wherein the panels of a row are fastened together with the interposition of crossbars . Fig. 5 is a sectional view of a detail showing a method for direct mutual fastening of the panels of a row. Figs . 6 and 7 show two particular embodiments of the inventive structure, for use in the making of prefabricated walls . Fig. 7 and 8 illustrate a further variant of the structure according to the present invention. Fig. 9 and 10 show a further embodiment of the invention in which projection elements of the abutting edge of each panel can be removably secured to the said abutting edges . Fig. 11 show the corner parts of a panel according to the invention which is mounted in a frame, the shape of the panel and of the frame being not precisely identical and the differences being compensated by differently thick projection elements. Fig. 12 show a front view on part of an abutting edge of a panel according to the present invention on which a row of spot or dot shaped projection elements is provided. Fig. 13 show a front view similar to fig. 12 in which continuous elongated projection element is provided. Fig. 14 show a lateral view fo the projection element of figure 13 while a part of the abutting edge is illustrated with discontinuous lines . Fig. 1 shows a structure for poured concrete forms for making concrete walls 1 or the like, such as vertical walls, horizontal and/or inclined walls and/or columns and/or pillars and/or similar poured concrete structures according to prior art. This structure generally comprises a plurality of studs or joists 2, 2 ' , 2 ' ' , generally consisting of elongate boxlike steel elements or the like, particularly having a rectangular section. Fig. 1 shows the portion of a prior art structure corresponding to a side end of the wall 1, whereby an end stud or joist 2 and an intermediate stud or joist 2' , 2' ' which is formed by coupling two elements 2', 2' ' that are substantially identical to the end stud 2. This arrangement provides considerable advantages in terms of modularity, as well as simple construction and assembly of the structure units . The studs or joists 2, 2', 2"' are designed to support a plurality of panels 3 that are disposed side by side in generally parallel rows. The end stud or joist 2 and the element 2'' of the intermediate stud or joist 2, 2' ' are placed at such a distance from each other that each panel 3 has to opposite end edges resting thereon. In order that the contact surface of the concrete against the structure surface may be as flat and continuous as possible, both the end stud 2 and the two studs 2 ' , 2' ' that form the intermediate stud have a longitudinal ridge 102, 102', 102' ' on the side turned toward the wall 1, said ridge having a height that substantially corresponds to the thickness of the panel 3 so as to generate stepped abutment surfaces 202, 202', 202", which allow the panel 3 to be substantially flush with the apices of the ridges 102, 102', 102''. Nevertheless, due to unavoidable tolerances encountered when mutually positioning panels 3 and studs or joists 2, 2', 2'', gaps 4 may occur which unavoidably create marks on the surface of the wall 1 that faces toward the structure. The problem is only partly solved by filling said gaps 4 with silicone or the like, which further implies considerable time and cost requirements. Referring now to Figs. 2 and 3, the portion of an inventive structure close to the intermediate stud or joist 2', 2'' is shown, wherein the above drawback is obviated, by providing that the ridges 102 ' , 102 ' ' of the two elements 2 ' , 2 ' ' that form the intermediate stud or joist have a smaller height than in Fig. 1, and that each of the two opposed panels 3 has a stepped abutting surface 203, so that the two panels 3 may be placed in contact with each other and fully cover the intermediate stud or joist 2, 2', 2''. Thanks to this arrangement, the impression of marks on the wall 1 is positively obviated. Nevertheless, in order to prevent the formation of a single residual gap due to an imperfect contact between panels 3, each panel 3 has a stepped abutting edge in form of a strip consisting in a pre-shaped profiled element 5 at its edge facing toward the opposite panel 3, which element is made of a plastic, so that, when the two opposite panels 3 abut against the two elements 2', 2'' which form the intermediate stud or joist, the mutually facing ridge portions of the two stepped pre-shaped profiled elements 5 come in contact with and slightly compress each other thereby removing any residual gap. Each stepped pre-shaped profiled element 5 may be attached to the edge of the panel 3 by physico-chemical bonding, e.g. gluing or, for instance, by injection over molding . As an alternative thereto or in combination therewith, means may be provided for mechanical anchorage, for instance screw driving and/or nailing. In order to increase the contact surface and provide a better anchorage between the stepped pre-shaped profiled element 5 and the edge of the panel 3, the stepped pre-shaped profiled element 5 has a plurality of longitudinal ridges 105 on the side that faces toward the edge of the panel 3, for engagement in corresponding grooves on the edge surface of the panel 3. Tlie inverted arrangement may be obviously also provided, i.e. the ridges may be provided on the edge surface and the grooves may be provided on the surface of the stepped element 5 turned toward the edge of the panel 3. Referring now to Fig. 4, panels 3 of the same row may be also engaged along the two remaining edges. This purpose is achieved by interposing crossbars 6 between adjacent panels 3 of the same row. These crossbars 6 are connected at their opposite ends to the studs or joists 2, 2', 2' ' and may be made in the same manner as the studs or joists 2, 2', 2'' described above, while the corresponding abutting edges of the panels 3 may also have a stepped shape as described above. Therefore, when required or desired, a frame may be provided that supports the panels along all four edges or along all the edges thereof. Referring now to Fig. 5, the possibility is shown of directly fastening together adjacent panels 3 of the same row without interposing crossbars 6. In order to obtain an optimal result and prevent gaps from occurring at each of the two mutually facing edges of two panels 3, a pre-shaped profiled element 7, 7' is provided, that may be attached to the edge of the panel 3 by physicochemical bonding, e.g. gluing, and/or by mechanical means. Once more, ridges and/or grooves may be provided on the mutually facing surfaces of each of the pre-shaped profiled elements 7, 7' and the edge of the panel 3, for the purpose of increasing the contact surface therebetween. The pre-shaped profiled element 7 has a center longitudinal ridge 107 which is adapted for engagement in a corresponding center longitudinal groove 107' on the pre-shaped profiled element 7' , for tightly coupling the two panels 3. Alternatively, the two pre-shaped profiled edges 7, 7' may have any other complementary shape, for instance a stepped shape. The invention may be not only used for the construction of concrete forms for making several different structural elements of building constructions, the combination of joists, studs, crossbars, and panels according to the invention may be advantageously used to make prefabricated walls. Here, the panels may be provided on one side only and/or on both sides of the bearing frame, thereby forming two finishing walls with a perfectly finished exposed face. Each wall, formed by a number of adjacent panels externally covers the bearing frame elements . The studs and joists or crossbars or any other elements of the bearing structure have the same construction on both opposite faces for abutment against the panels, i.e. the above described ridges 102, 102', 102'". Therefore, the bearing structure elements, i.e. the joists, crossbars, studs or the like are interposed between the two walls, and also form wall spacing members, to create an air gap there between. This air gap may be a housing for technical systems, such as electrical and/or hydraulic systems, or the like. It shall be noted that the panels of the two walls may have different thicknesses. Hence, for example, in outside walls, the panels of the outer exposed wall may be thicker than those that form the parallel inner wall. Similarly, in horizontal or inclined, i.e. non vertical walls, panel thickness may vary depending on the bearing or non-bearing nature of such horizontal or inclined walls. In a typical horizontal wall structure, e.g. for making floors, the wall that forms the surface to be walked on may have a greater panel thickness, whereas the bottom parallel wall that forms the ceiling of the room below the horizontal wall, which has finishing purposes, may have a smaller panel thickness. The above structure composed of panels and a bearing or support frame may be also used in any embodiment described for making building structures, such as prefabricated rooms, shelters or simple vaults, i.e. for wholly or partly closed structures. Here, the particular panel edge design, when combined with the resilience or softness of the material and with the particular shape of the joists or studs of the structure provides a few advantages . First, the modular prefabricated structure provides optimized transportability, as it can be very quickly assembled on site. Therefore, the ratio between the volume of the element being carried and the weight thereof is optimized. With the same weight load, much larger shelters or rooms may be made as compared with those that may be only carried as prefabricated cells . Furthermore, the resilient or soft edges automatically provide, upon contact there between, an at least partial sealing action against weather conditions, such as water and wind, and are limited to a single junction line along the panel edges. These edges have somewhat a gasket-like action. Sealing thereof is quick and fast, a single junction line being provided for each contact edge between adjacent panels. Moreover, since said edges fully cover the outer side of the bearing frame, which is generally made of a metal material and has a high thermal conductivity, the fact that the frame is fully externally covered by the panel edges allows to enhance thermal insulation of the structure, by simply forming a thermally insulating barrier between the bearing frame and the outside and/or inside environment. The effect is further enhanced when two wall shells are provided, an inner shell and an outer shell. Furthermore, when two shells are provided, the air gap formed by the two panel shells may be filled with intermediate thermally insulating panels, such as foam panels . Since the rame is of the prefabricated type, said intermediate thermally insulating panels may also have a predetermined size and shape, which is complementary and corresponding to the distance between elements such as the oists and the studs or the crossbars of the bearing frame. The above structure facilitates the construction of prefabricated building structures for the civil protection and military fields, for instance emergency shelters for persons or things . These shelters have the advantage of providing water and weather tightness and of having the function of thermal barrier between the support frame and the outer surface of the shell. According to the above mentioned features of the structure of the present invention each panel is formed by a panel plate and peripheral strips made by pre- shaped elements 5, 7 which are bonded to the peripheral edges of the plate or are provided by shaping with machines or molding the peripheral edges of the panel plate depending form the material of which the panel plate is made. The peripheral strips forms the abutting edges of the panels and are of elastic compressible material. Thus a wall for a concrete form or a generic prefabricated wall may be mounted by mounting the frame and then mounting the panel or the panels in the frame by pressing it in the frame. Thus the panel is retained in the frame by compression forces acting in a direction parallel to the surface of the panel. Figures 7 and 8 illustrates a further improvement of the structure according to the present invention. According to this improvement, the surface of each or of at least part of the abutting edges which is essentially parallel to the direction of pressing the panel in the frame or essentially perpendicular to the surface of the panel plate has at least one continuous protrusion or lip which is also of elastic compressible material and which is indicated by 303 in the figures 7 and 8. This protrusion is compressed and deformed when the panel plate with the peripheral strips bonded to it is mounted by pressing inside the frame. As already discussed above, the abutting edges has to ensure different functions which leads to different mechanical features, particularly relatively to hardness or compressibility of the abutting edges . Further to the fact that the abutting edges has to ensure mounting of the panel by simply pressing it into the frame and also avoiding the formation of marks in the concrete wall or gaps between adjacent panels, the said abutting edges has also the function of compensating dimensional tolerances between frame and panel and or different thermal expansions or shrinking of the panels and of the frame or other kind of expansions or shrinking for example due to different moisture content, of protecting the edges of the panel plate from damage and from sealing the panel edges from contact with water or moisture. On the other hand the abutting edges of the panels must have sufficient stability so they are not compressed by the concrete. These different f-unctions are ensured by the embodiment according to figures 7 and 8. Indeed the elastic compressible projections 303 allow the compensation of high dimensional tolerances between the panels or plates and the frame without renounciating abutting edges which can stand the high pressures of the liquid, concrete in order not to be compressed causing marks on the finished walls. The projections or lips enhances the abutting edges relatively to their mechanical behavior in such a way that the abutting edges show different compressibility in a direction perpendicular to the surface of the panel and in a direction parallel to the surface of the panel . The said projection elements 303 can be spot or dot like elements or elongated elements extending over a certain part of the length of the profiled element forming the abutting edges of the panel or plate. This projections or lips 303 can be provided of the same material of the abutting edges of the panel and provide for a different compressibility in a direction parallel to the surface of the panel due to their shape and dimension. According to a modified embodiment the said projections or lips can be also made of a different material which has a different elastic compressibility than the material out of which the abutting edges are made. When the projections or lips are of the same material of the abutting edges they can be made together with the profiled elements forming the said abutting edges of the panel, such as by injection or extrusion or adhesion. When the projections or lips 303 are made of a different material as the abutting edges case the said projections can also be formed by co-injection or co- extrusion by injecting the said projections or lips on an already shaped profiled element put in the mold. According to a further feature the said abutting edges can be formed by a profiled elongated element provided in combination with separated projection elements or lips 30. In order to secure the said separated projection elements or lips 30 to the profiled element forming the abutting edges of the panel or plate mechanical means are provided which in the removable securing means, in particular toothed securing pins 31 which allow the said projections or lips to be taken away and substituted with other element or lips. The toothed securing pins 31 are engaged by elastic forcing in holes 40 in the abutting edges of the panel or plate. More than one elongated projection or lip 303 or more than one row of spot or dot shaped projection elements 303 can be provided on an abutting edge of a panel or plate. As it appears clearly form figure 11 the projection elements or lips are particulalry advantageous for allowing the compensation not only of dimensional differences between the panel or plate but also for compensating differences in shape or position This problem is solved by providing a series of differently dimensioned projection elements 303. In this case each differently dimensioned projection element or lips has a different thickness in the direction of protrusion form the surface of the profiled element to which they have to be secured. In figure 11, the frame and the panel or plate are not correctly aligned so that the edges of the panel are not parallel to the edges of the frame. This is due to a non correct shape of the panel or of the frame. Thus ofr securing the panel in the frame in a stable, rapid and economic way differently protruding projection elements 303, 303', 303'' are provided which fills differently gaps along the extension of the edges of the panel between the edges of the panel and the opposed edges of the frame. Referring to the preferred embodiment of figures 9 and 10, the projection elements or lips 303 are formed by a toothed securing pin 30 which carries a projection head 31 being made of compressible material, while holes 40 are provided at predetermined positions on the profiled element in which the toothed securing pin 30 can be removably engaged by elastic forcing the said securing pins in the said hole . In figures 9 and 10 in order to highlight that more than one continuous projection element can be provided or that two rows of separated dot or spot like projecting elements can be provided one of the two projecting elements and the corresponding hole 40 in the atoutting edge of the panel are illustrated with discontinuous lines. Figure 12 illustrates a front view on an abutting edge 5 of the panel according to the present invention which abutting edge 5 is provided with one row of spot- shaped projection elements each one having its own toothed securing pin. The toothed securing pins 30 are preferably made of relatively rigid material such as plastic material as polypropylene or the like. In this case the projection elements can be made by co-injection over molding or other known processes . In figure 13 and 14 an alternative embodiment of the projection elements is shown. In figure 13 and 14 the projecting elements has an elongated shape extending for at least a part of the length of the profiled element forming the abutting edge of the panel. A supporting strip 33 of rigid plastic material has one or more toothed securing pins 30 at certain intervals one form the other while the strip carries one or more projection heads aligned along its length or a continuous projection element 30' extending for at least part or for the entire length of the said supporting strip. On the profiled element forming an abutting edge of a panel there can be fixed a certain number of the said dot or spot-like projecting elements in combination with one or more elongated projection elements . It has to be stressed that the term toothed securing pin is to be intended as indicating various possible pins having not a smooth surface. Particularly suitable pins are the ones used in the automotive industry for fixing lining interior panels or other lining sheets to the doors and or ceiling or to other parts of then bodywork of a vehicle. As it appears clearly form the above description a panel having the combination of abutting edges 5 and of projection elements 30 which can be removably secured to the abutting edge 5 can be finished for being mounted and secured in the frame by engaging the securing pin 31 of a certain number of projection elements 303 into the holes 40 of the abutting edges of the said panel. If there are differences in shape which at least along one edge determines that the edge 5 of the panel is not parallel to the corresponding stud or joists of the frame, then the said abutting edge can be provided with differently protruding projection elements as illustrated in figure 11. When after removal from the frame, the panel has to reused within another frame, than at least part of the said projection elements can be teared off the abutting edges and substituted by dimensionally more suitable different projections elements 303 which better fits the new frame in which the panel has to be secured. This operation can be done very rapidly and at low costs. Also the projecting elements are very cheap. According to a further feature of the invention a material is used for the abutting edges having a hardness shore A between 90 and 100 and/or a hardness shore D between 39 and 55. Particularly suitable material for the strips forming the abutting edges are polypropylene and especially polyurethane . Preferably the abutting edges are formed by polyurethanes and particularly by polyurethanes obtained from the co-polymerization of polyols with iso-cyanates . The said polyurethanes can be molded either by casting at low pressure or by high pressure injection in order to obtain the strips forming the abutting edges according to the present invention. In order to adjust the hardness and other mechanical properties and to stabilize the dimensions of the molded strips by reducing internal tensions during injection and also in order to reduce costs the polyurethanes can be also charged with inorganic charge materials . It is to be highlighted that although the panel and the structure according to the present invention is particularly suited for prefabricated modular walls of forms for pouring concrete, the same structure can be used for easily and rapidly building walls and roofs of water resistant enclosures or rooms. The structure of the present inventin is particularly suited for building water resistant buildings for civil protection tasks or in every situation where an edifice has to be assembled and disassembled rapidly, ensuring nevertheless a high resistence to the water and wind and a good thermal insulation.

Claims

CLAIMS 1. A structure for modular prefabricated poured concrete forms for making vertical walls, horizontal walls such as ceilings, slabs or the like, and columns or pillars, comprising a frame made of at least two studs or joists (2, 2', 2'") for supporting at least one panel (3) or a plurality of adjacent panels (3) , which studs or joists (2, 2', 2' ') are at such a distance from each other that each panel (3) has at least two opposite edges abutting against said two studs or joists (2, 2', 2''), and each abutting edge of each panel (3) has a stepped cross section (203) and the surface of each stud or joist (2, 2', 2' ') against which a panel edge abuts has a complementary stepped cross section (202 ' , 202 ' ' ) , so that the edge of the panel (3) is fully superimposed on the side of the stud or joist (2, 2', 2'') against which it abuts, characterized in that each abutting edge having a stepped cross section is integral with the panel or is made by a strip consisting in a pre-shaped element (5) which is secured to the panel peripheral edges by means of adhesive of by chemical/physical bonding.

2. A structure according to claim 1, characterized in that the bonding of the strip (5) forming the abutting edges to the peripheral edges of the panels are such that a water sealing effect is obtained at the interface between the said strips and the peripheral edges of the panel.

3. A structure according to claim 1 or 2, characterized in that the abutting edges are made of compressible material such as rubber or rubber like plastic material or any kind of plastic material which has compressible elastic behavior.

4. A structure according to claim 3, characterized in that the abutting edges are formed by polyurethanes and particularly by polyurethanes obtained from ttie co- polymerization of polyols with iso-cyanates .

5. A structure according to claim 4, characterized in that the abutting edges are molded either by casting at low pressure or by high pressure injection in order to obtain the strips forming the abutting edges according to the present invention.

6. A structure according to one or more of the preceding claims 4 or 5, characterized in that the polyurethanes are charged with inorganic charge materials .

7. A structure according to one or more of the preceding claims, characterized in that the panel is a laminated panel having at least two layers, one of which is a cover layer of plastic material, included thermoplastic fibers, and the other is a supporting layer, while the strips (5) forming the abutting edges are bonded at least to the cover layer of the panel by means of chemical/physical bonding forming a water tight junction between the said cover layer of the panel and the strips (5) forming the abutting edges.

8. A structure according to claim 7, characterized in that the said strips (5) forming the abutting edges are also be bonded to the peripheral edges of the supporting layer.

9. A structure according to claims 7 or 8, characterized in that the supporting layer is made of different materials than the cover layer such as for example wood.

10. A structure according to claims 8 or 9, characterized in that the supporting layer is of wood or the like and is directly bonded to the strips (5) forming the abutting edges and the corresponding peripheral edge of the wooden supporting layer or and adhesive layer is provided between the adhering faces of the strips (5) forming the abutting edges and the peripheral edge of the panel.

11. A structure according to one or more of the preceding claims 7 to 10, characterized in that, the panel is made of at least one supporting layer made of at least one layer of wooden material and which supporting layer is covered on both of the opposing surfaces by a cover layer of plastic material bonded thereto, the strip or strips (5) of plastic material forming the abutting edges being bond to the peripheral edges of the panel by chemical/physical bonding with at least each one of the peripheral edges of the cover layers and/or also with the peripheral edge of the supporting layer.

12. A structure according to one or more of the preceding claims, characterized in that the said abutting edges have such an elastic compressibility behavior or index or such an hardness to form a compressible sealing and elastic retaining element for the panels into the frame.

13. A structure according to one or more of the preceding claims, characterized in that the abutting edges are made in such a way as to show different compressibility in a direction perpendicular to the syrface of the panel and in a direction parallel to the surface of the panel.

14. A structure according to one or more of the preceding claims, characterized in that at least the surface of the abutting edges which is essentially transversal or perpendicular to the surface of the panel or which is essentially parallel or slightly inclined relatively to the direction of pressing the panel in the frame has at least one or more continuous projections or lips or one or more rows of discontinuous or spot or dot like space apart projections or lips which are compressed and deformed against the corresponding surface of the stepped studs or joists of the frame when the panel together with the abutting edges is pressed into the frame itself.

15. A structure according to one or more of the preceding claim 14, characterized in that the said projection elements can be spot or dot like elements or elongated elements extending over a certain part of the length of the profiled element forming the abutting edges of the panel or plate.

16. A structure according to one or more of the preceding claims 12 to 15, characterized in that the said projecting elements or lips are of the same material of the abutting edges of the panel and provide for a different compressibility in a direction parallel to the surface of the panel due to their shape and dimension.

17. A structure according to one or more of the preceding claims 12 to 15, characterized in that The said projections or lips are made of a different material as the abutting edges the having a different elastic compressibility as the material of the abutting edges, particularly a higher compressible.

18. A structure according to one or more of the preceding claims 15 to 17, characterized in that the projections or lips are formed together with the profiled elements forming the abutting edges of the panel, such as by injection or extrusion and or coinjection or co-extrusion or adhesion.

19. A structure according to one or more of the preceding claims 12 to 18, characterized in that , the said abutting edges can be formed by a profiled elongated element are provided in combination with separated projection elements or lips, mechanical means being provided for securing the said projection elements or lips to the said elongated profiled elements .

20. A structure according to claim 19, characterized in that the said mechanical means for securing the said projection elements or lips are removable securing means allowing the said to be taken away and substituted with other projection elements or lips .

21. A structure according to claim 20, characterized in that a series of differently dimensioned projection elements is provided which differs at least one form another relatively to their thickness in the direction of protrusion form the surface of the profiled element to which they have to be secured.

22. A structure according to one or more of the preceding claims 20 or 21, characterized in that the projection elements or lips comprise a toothed securing pin which carries a projection head being made of compressible material, while holes are provided at predetermined positions on the profiled element in which the toothed securing pin can be removably engaged by elastic forcing the said securing pins in the said holes .

23. A structure according to claim 22, characterized in that the toothed securing pin is made or relatively rigid material such as plastic material as polypropylene or the like.

24. A structure according to one or more of the preceding claims 19 to 23, characterized in that the projection elements can be made by co-injection or the like of the projecting head and of the securing pin.

25. A structure according to one or more of the preceding claims 19 to 24, characterized in that the projecting elements have an elongated shape extending for at least a part of the length of the profiled element forming the abutting edge of the panel.

26. A structure according to claim 25, characterized in that a supporting strip of rigid plastic material has one or more toothed securing pins at certain intervals one form the other while the strip carries one or more projection heads aligned along its length or a continuous projection element extending for at least part or for the entire length of the said supporting strip.

27. A structure according to one or more of the preceding claims 19 to 26, characterized in that A profiled element is provided forming an abutting edge and on the said profiled element a combination of a certain number of the said dot or spot-like projecting elements and of one or more elongated projection elements is secured.

28. A structure according to one or more of the preceding claims 19 to 27, characterized in that the term toothed securing pin have a ruvid surface.

29. A structure according to one or more of the preceding claims 19 to 27, characterized in that the securing pins are of the kind used in the automotive industry for fixing lining interior panels or other lining sheets to the doors and or ceiling or to other parts of then bodywork of a vehicle.

30. A structure according to one or more of the preceding claims, characterized in that more than one panel and more than one frame is provided and the said panels are mounted in adjacent frames, the stepped abutting edges are shaped in such a way that the external peripheral edges of the said abutting edges of adjacent panels adheres one to the other the surfaces of the said abutting edges parallel to the surface of the panel and oriented against the concrete, i.e. opposite to the frame being flush one with the other and flush with the corresponding surface of the panels .

31. A structure according to one or more of the preceding claims, characterized in that the strips forming the abutting edges of the panel or of the panels have a hardness between 90 and 100 shore A and/or 39 and 55 shore D 32. A structure as claimed in one or more of the preceding claims, characterized in that the studs or joists (2, 2', 2'') which form the frame are tubular and may have any design whatsoever, particularly they have a rectilinear design and are arranged on the same plane, more particularly parallel to each other. 33. A structure as claimed in claim 32, characterized in that the panels (3) may have any size and shape whatsoever, and be equal to or different from each other, particularly they all have the same rectangular shape or sets of panels (3) are provided, so that the panels (3) within each set are identical in shape and/or size, and the panels (3) of a set are different in shape and size from the panels (3) of the other sets . 34. A structure as claimed in claim 32 or 33, characterized in that the frame is composed of at least three studs or joists (2, 2', 2''), two at the ends (2) and one in the middle (2', 2''), and which studs or which joists (2, 2', 2'') are arranged in such a manner as to support two parallel rows of adjacent panels (3) , each of which panels (3) has a stepped edge (203) abutting against an end stud or joist (2) , and an opposite stepped edge (203) of each panel (3) abutting against the intermediate stud or joist (2', 2''), which intermediate stud or which joist (2', 2 ' ' ) has two opposite abutment surfaces (202', 202'') each of which has a stepped cross section which is complementary to the corresponding abutting edge (203) of the panel (3) . 35. A structure as claimed in one or more of the preceding claims 32 to 34, characterized in that the intermediate stud or joist (2', 2'') has a center longitudinal ridge (102', 102'') on the panel (3) abutment side, whose width is substantially twice the depth of each of the two stepped edges (203) of the two opposite panels (3) , as seen in a direction parallel to the surface of each panel (3) , so that the two facing portions of the two stepped edges (203) of the two opposite panels (3) are in contact with each other and the intermediate stud or joist (2', 2'') is completely covered on the side against which said two abutting edges (203) of the two opposite panels (3) abut. 36. A structure as claimed in claim 35, characterized in that the intermediate stud or joist is formed by two parts (2', 2'') that are longitudinally separated along a median plane substantially perpendicular to the surface of the panels (3) , and the center longitudinal ridge is divided into two halves (102', 102''), each of which is has a width substantially corresponding to the depth of the stepped abutting edges (203) of the two opposite panels (3) , as seen in a direction parallel to the surface of the panels (3) . 37. A structure as claimed in one or more of the preceding claims 32 to 36, characterized in that each of the two end studs or joists (2) is substantially identical to each half (2', 2'') of the intermediate stud, whereby the intermediate stud (2', 2'') is formed by coupling two end studs (2) disposed in mirror arrangement, i.e. with the stepped abutment surfaces (202', 202'') turned against each other, and the structure is composed of a plurality of substantially identical studs or joists (2, 2", 2"'). 38. A structure as claimed in one or more of the preceding claims 32 to 37, characterized in that means are provided for removably fastening two end studs or joists (2) in such a manner as to form the intermediate stud (2', 2") . 39. A structure as claimed in one or more of the preceding claims 32 to 38, characterized in that the complementary stepped edges (203, 202', 202'') of each stud or joist (2, 2', 2" ') and each panel (3) have a rounded or polygonal design and preferably have complementary rectangular shapes. 40. A structure as claimed in one or more of the preceding claims, characterized in that the panels are at least partly of plastic material and the opposite stepped abutting edges (203) of each panel (3) are formed at the same time as the panel (3) , for instance during molding and/or pressing of the panel (3) , wherein the stepped edges (203) are provided in the mold design, or are formed at a later time, particularly by removal of material, effected by milling or the like. 41. A structure as claimed in one or more of the preceding claims, characterized in that the panels (3) are composed of multiple modular members, such as wood blocks or the like, which are assembled together along a single plane and/or different planes by gluing or the like. 42. A structure as claimed in one or more of the preceding claims, characterized in that the panels (3) have at least one outer coating layer, on one or both faces, preferably with waterproofing properties, for instance made of plastic and/or paint. 43. A structure as claimed in one or more of the preceding claims, characterized in that the opposite stepped abutting edges (203) of the panels are made of elements (5) that are manufactured separately from the panels (3) , for instance pre-shaped profiled elements (5) and are bonded to the edges of the panels (3) by mechanical fastening, e.g. nailing and/or screw driving, and/or physico-chemical bonding, for instance gluing. 44. A structure as claimed in one or more of the preceding claims, characterized in that the strips (5) that form the stepped abutting edges (203) may be made of one or more materials, other from those that constitute the panel (3) , or may be made of the same material as that of at least one layer or part of the panel (3) . 45. A structure as claimed in one or more of the preceding claims, characterized in that the waterproofing layers that coat the two faces of the panels (3) also extend in the areas of the two opposite stepped abutting edges (203) and possibly even to the other two edges, so that the panels (3) are wholly waterproofed, for instance by using paint. 46. A structure as claimed in one or more of the preceding claims, characterized in that the strips (5) that form the stepped abutting edges (203) are made of plastic, are bonded to the corresponding edges of the panel (3) by injection overmolding. 47. A structure as claimed in one or more of the preceding claims, characterized in that the mutually bonded facing surfaces of the strips (5) that form the stepped abutment edges (203) as well as the edge of the panel (3) itself have a flat shape. 48. A structure as claimed in one or more of the preceding claims 1 to 46, characterized in that the mutually bonded facing surfaces of the strips (5) which form the stepped abutment edges (203) and the edge of the panel (3) have one or more continuous or discontinuous complementary ridges (105) or grooves on or in the edge of the panel (3) and on or in the facing edge of the pre-shaped profiled elements (5) which form the stepped abutting edges (203) , which ridges (105) and which grooves are in mutual engagement to increase the contact surface and provide a better coupling, possibly by mechanical forcing, between the step profiled edge (5) and the edge of the panel (3) . 49. A structure as claimed in one or more of the preceding claims, characterized in that the frame is composed of a plurality of studs or joists (2, 2', 2'') oriented in a first direction and a plurality of crossbars (6) oriented in a direction transverse to the former, which studs or joists (2, 2', 2'') and which crossbars (6) separate each panel (3) from the adjoining panels (3) along the pairs of edges that extend in the two directions transverse to each other, each panel (3) having stepped abutting edges on at least four sides or on all sides . 50. A structure as claimed in claim 49, characterized in that the crossbars (6) are made in the same manner as the studs or joists (2, 2' , 2' ' ) as claimed in one or more of the preceding claims, whereas the mutually facing edges of the panels (3) of the same row have stepped edges for abutment against the stepped edges of the crossbars (6) , which stepped edges are also made as claimed in one or more of the preceding claims . 51. A structure as claimed in one or more of the preceding claims, characterized in that the frame is only composed of a plurality of studs or joists (2, 2' , 2'') extending in a first direction, the adjacent panels (3) of each row of panels (3) between two studs or joists (2, 2', 2'') being fastened together directly along direct contact edges (7, 7') of the adjacent panels (3) of each row of panels (3) . 52. A structure as claimed in claim 51, characterized in that the facing direct contact edges (7, 7') between two adjacent panels (3) of the same row have complementary interlocking, wedging or similar profiles (107, 107') . 53. A structure as claimed in claims 51 or 52, characterized in that direct contact edges (7, 7' ) between adjacent panels (3) are made as claimed in one or more of the preceding claims, like the stepped edges (5) of the panels (5) for abutment to the studs or joists (2, 2', 2") . 54. A structure as claimed in one or more of the preceding claims, characterized in that the surface subtended by the frame and the panels (3) may have any design whatsoever, particularly a flat design, which may be horizontal, vertical or inclined. 55. A structure as claimed in one or more of the preceding claims, characterized in that it is used for making prefabricated partition and/or curtain and/or outside vertical or horizontal walls, to divide rooms in existing building structures or for making prefabricated building structures such as enclosures, shelters, protective housings, sheds, tunnel vaults or the like, particularly for civil protection purposes or for making temporary emergency housing units . 56. A structure as claimed in claim 55, characterized in that the elements that form the bearing frame or a bearing structure are associated to multiple adjacent panels arranged on two opposite sides thereof, to form two substantially parallel walls between which said elements of the bearing frame and/or structure are interposed. 57. A structure as claimed in claim 55, characterized in that, for each of the two substantially parallel walls, the elements of the bearing frame and/or bearing structure have surfaces for abutment against the panels that are shaped as claimed in one or more of the preceding claims . 58. A structure as claimed in claim 55 or 56, characterized in that the two substantially parallel walls form an air gap there between . 59. A structure as claimed in one or more of claims 55 to 56, characterized in that the panels of the two substantially parallel walls have different thicknesses depending on their function and/or from each other. 60 A method for building a modular prefabricated wall particularly for a form for poured concrete which methods comprises the following steps : a) Providing a frame made of at least two studs or joists adapted to support at least one panel or a plurality of adjacent panels, which studs or joists are at such a distance from each other that each panel has at least two opposite end edges abutting against said two studs or joists; b) providing each abutting edge of each panel of elastic compressible material and with a stepped cross section; c) providing the surface of each stud or joist against which a panel edge abuts with a complementary stepped cross section; d) inserting the panel in the frame the panel being retained in position within the frame by the said abutting edges; characterized in that, each abutting edge of the panel is made integer or bonded stably to the corresponding peripheral edges of the panel and the panel is pressed together with the abutting edges integrated on it or bonded to it into the frame. 61. A method according to claim 60, characterized in that the abutting edges are formed by pre-shaped strips being bonded by physical-chemical bonding to one or more of the peripheral edges of a panel plate . 62. A method according to claim 60, characterized in that the abutting edges are formed by injection over molding of a panel plate. 63. A panel for building modular walls or the like having at least one layer and at least one edge which has a stepped or L shaped cross-section, characterized in that the said stepped or L shaped edge being stably secured to the edge of the panel. 64 A panel according to claim 63, characterized in that it is constructed according to one or more of the preceding claims 1 to 31 and 39 to 49 and a method for building the said panel according to one ore more of the claims 61 or 63.