WO2014016752A2

WO2014016752A2 - Anchorage system for structural panel in wood

Info

Publication number: WO2014016752A2
Application number: PCT/IB2013/055998
Authority: WO
Inventors: Doriano CANELLA
Original assignee: Canella Doriano
Priority date: 2012-07-26
Filing date: 2013-07-22
Publication date: 2014-01-30
Also published as: ITPD20120230A1; WO2014016752A3

Abstract

The invention is a method for providing a structural wooden panel of the CLT type (C) with a perimeter anchorage system suited to connect connectors or connection systems with high ductility, through: the creation of milled-hollow portions (L) on the four narrow edges of a structural wooden panel of the CLT type (C); the creation, on the bottom of said hollow portions (L), of further milled portions suited to obtain recesses (N) and/or holes (F1, F); the introduction in said holes (F and/or F1) and/or recesses (N) and hollow portions (L) of a specific adhesive and of corresponding threaded bars (20) and/or shaped bars (21), as well as the insertion in said hollow portions (L) of the assemblies developing longitudinally constituted by at least one bar/section (B), joints (40) and related accessory materials (41, 42, 43); the firm fixing, mechanically and with specific adhesives, of each assembly made up of said bar/section (B) complete with joints (40) and related accessory materials (41, 42, 43) to said bars (20, 21 ), thus obtaining a structural wooden panel of the CLT type (C1) complete with a perimeter anchorage system for external connectors.

Description

ANCHORAGE SYSTEM FOR STRUCTURAL PANEL IN WOOD

DESCRIPTION

Field of application of the invention

The present invention belongs to the sector of prefabricated wooden systems intended for the construction industry and in particular relates to a method for providing CLT type structural wooden panels with a perimeter anchorage system for external connectors and the panels obtained by implementing such a method.

State of the art

The reference structural wooden panels are internationally identified with the abbreviation "CLT", an acronym that stands for "Cross Laminated Timber", that is, "layers of boards laid crosswise with respect to each other and glued". In Italy this type of panel is also identified with the term XLam and other countries and/or manufacturers sometimes use their own terminology. In any case, the term CLT used in this document extends its validity to all the names given to this type of panel regardless of location and of who assigned them. The term "standard CLT" is used in this document to identify structural wooden panels according to the state of the art manufactured based on dedicated CAD/CAM systems and CNC machines utilizing wooden boards properly cut to size, planed, sanded and then glued together in layers, with each layer arranged at a right angle with respect to the adjacent boards they are glued to. The number and thickness of the individual layers of boards used depend on the characteristics that a certain structural panel must have, for a total indicative thickness from 8-9 cm up to more than 40-50 cm. Normally, standard CLT panels are composed of a minimum of three layers up to 5 to 7 layers of boards laid crosswise (and even up to 9 to 11 and beyond in specific cases). At the end of the various processes the panels obtained, depending on their size, thickness, shape and mechanical characteristics, can be used to make load bearing and non-load bearing walls, floors and roofs of buildings intended for residential, industrial and commercial use as well as for facilities for general public use (schools, gyms, hospitals, churches, etc). To achieve a structural wooden panel made of layers of boards laid crosswise with respect to each other, in addition to the joining method that uses specific adhesives, some manufacturers use other methods including joining the various layers of boards with special aluminium nails or pegs made of wood of well-defined species. Regardless of the manner in which the various layers of boards that form such a type of panel are joined together, the end result is substantially similar, that is, they are structural wooden panels intended for the same purposes. The CLT type structural wooden panels available on the market, regardless of how the various layers of boards are joined, are a good solution for the construction of buildings of various kinds, even in seismic zones; it should be noted, however, that these panels and the structures constructed with them have limitations including the methods of connection with each other and/or with other components in use today, which employ traditional techniques such as the use of screws-nails- brackets-pins and the like, even if with a technologically modern twist, and it is along this line that an alternative solution is proposed.

The invention in detail

1) The present invention relates to a method for providing a standard CLT structural panel C, as shown in Figure 1, with a perimeter anchorage system suited to the use of specific high- ductility external connectors or joining systems, and to the panels obtained by the implementation of this method.

2) The main object of the present invention is to propose a method for providing a standard CLT structural panel C, which can be constructed on scale, with a perimeter anchorage system for external connectors, through the use of bars/profiles and/or rods, special connectors and accessories made of materials of any kind suitable for the purpose, including products of a ferrous nature and their derivatives, alloys, fibres in general and the like.

3) A second object of the present invention is to use this perimeter anchorage system, in conjunction with specific ductile connectors or joining systems with high dissipative capacity, already existing and/or to be designed and developed in the future, in order to produce CLT structural panels CI suitable for constructing buildings and/or structures intended for any use, with anti-seismic and other characteristics which represent an improvement with respect to those obtainable at present.

4) Another object of the present invention is to reduce, if not eliminate completely, the use of connection elements between panels pertaining to traditional carpentry in use today, such as screws-nails-pins-brackets and the like.

5) A further object of the present invention is to be able to use a CLT structural panel CI equipped with the perimeter anchorage system devised, also in conjunction with any type of items made of any material used and/or usable in the building and construction industry in general, in order to construct buildings with high anti-seismic characteristics, whether intended for civil, industrial, commercial, public and/or infrastructure use in general.

6) These and other objects indicated also in the claims are achieved by the method described below, without limitations regarding further improvements and/or variant embodiments which may not be described and/or illustrated in the attached drawings. For simplification purposes, only the following method will be described, that is, a method for providing a five-layer standard CLT structural panel C with a perimeter anchorage system for external connectors consisting of elements with longitudinal development, bars/profiles B with a generically box-shaped cross section, for example having a rectangular shape, in addition to at least one specific type of movable joint 40. It should be noted that the rectangular element B, like the joint 40, may have different shapes, sizes and proportions, be made of different materials, and in the same CLT structural panel C 1 components which are not uniform and/or homogeneous can coexist, depending on the specific characteristics required of a structural panel of this type as a function of the use it is intended for in order to construct a given building. In detail, with respect to said joint 40, it is specified that it can also be made up of a type of coupling similar to the joint 40 but already equipped with the relative external connector. It is further specified that a CLT structural panel CI thus obtained is only one of the possible products achievable with this method and therefore the invention in question extends its validity to any type of wooden product obtainable as a result of the present invention, such as, by way of a non-limiting example, structural wooden panels where each layer is laid crosswise with respect to the boards of the adjacent layer and wherein these layers are joined with suitable adhesives, aluminium nails, wooden dowels and/or the like. This invention has the object of obtaining CLT structural panels CI by incorporating, directly in the production plant, but in some cases perhaps even subsequently, a perimeter anchorage system for external connectors and/or joining systems with high ductility. The description of the method for providing a CLT structural panel C with a perimeter anchorage system for external connectors takes into consideration the use, for certain components, of mainly ferrous threadable material, while for others it is possible to use any material, even non-ferrous, such as alloys and/or fibres of any nature or other suitable material; in any case, regardless of the type of materials used, it does not require machining procedures, and does not produce results different from those indicated. The provision of a perimeter anchorage system for external connectors which is the subject of the present invention is implemented at the end of all the processes required to make a standard CLT structural panel C, according to the operations described below.

7) The process required to construct a CLT structural panel C 1 with a perimeter anchorage system for external connectors is described here below, and it should be noted that the reference numbers and letters of the components used and/or of the construction details are the same at each mention of them from the accompanying drawings:

- after completing the construction of a standard CLT structural panel C, for example with five layers of boards crossed in two generally transverse directions X-Y as shown in Figure 1, in the manner known and in use in the various manufacturing facilities, a robotic arm, and/or other suitable machinery-tools, is/are used to perform the following additional processing, equipping it/them with specific equipment;

- a cylindrical milling cutter tool is inserted in the head of the robotic arm, said cutter tool being adequately sized to create at least one groove-hollow portion L, preferably but not necessarily longitudinal, on all four narrow edges of the structural panel C, as shown in the partial cross- sections of Figures 2 and 3. The hollow portion L shall have a well -determined depth and width, as well as shape, so that it can house said longitudinal element B forming part of the perimeter anchorage system provided therein, as shall be described below;

- at the end of these processes, the milling tool is replaced with another milling tool having an adequate size and shape to create a series of recesses N, as shown in Figure 2, longitudinally spaced from each other at predetermined distances defined by means of precise structural calculations. These recesses N are made exclusively on the bottom of the hollow portion L of a pair of narrow edges opposite each other on a standard CLT structural panel C where said layers of boards 2 and 4 are arranged parallel to the hollow portion L;

- at the end of these processes, this second milling tool is replaced with a drill type tool in order to make holes Fl, as shown in Figure 2, having, for example, a generically rectangular cross section, preferably at least two in number for each recess N, starting from the bottom of the recesses N themselves. Said holes Fl, the result of precise structural calculations as regards their size and depth, are made at right angles with respect to the layers of boards 2 and 4 for the reasons set out below;

- at the end of these processes, the tool just used is replaced on the robotic arm with a drill tool in order to make holes F, for example cylindrical, as shown in Figure 3, obtained starting from the bottom of the hollow section L in the second pair of narrow edges of the standard CLT structural panel C intended to house the perimeter anchorage system. Also in this case the holes F are made at longitudinal distances from each other as well as with a depth and diameter that are predetermined by precise structural calculations and at the level of the layer of boards 3 and therefore are orthogonal to said layer 3 for the reasons indicated below;

- once all the milling-drilling operations have been completed on the four sides of the standard CLT structural panel C as described, the hollow portions L, recesses N, and holes F and Fl are cleaned of sawdust and shavings, advantageously by means of suction, so as to allow the insertion of the components necessary to make a perimeter anchorage system, that is, threaded bars 20 as shown in Figure 4, shaped bars 21 as shown in Figures 5, 5a, 5b and bars/sections B as shown in Figures 7, 8, 9, 9a, 9b (in addition to the specific adhesive necessary) in said perfectly clean hollow portions-recesses-holes L, N, F, Fl;

- the perimeter anchorage system for external connectors, shown herein, is composed of a series of components that will be assembled and joined together in the manner indicated below; in detail the necessary components are the following;

- Figure 4 shows a threaded bar 20 whose diameter and length are determined by precise structural calculations; it serves, once firmly inserted in the hole F indicated in Figure 3 by means of a specific adhesive, to secure the longitudinal element, consisting of said bar/section B, as described below; - Figures 5, 5a, 5b show different views of a shaped bar 21 comprising at least two legs 211 and having corrugated or knurled surfaces, which, like a threaded bar 20, once firmly inserted in the recesses N and in the holes Fl shown in Figure 2 by means of a specific adhesive, serves to fix the longitudinal element made up of the bar/section B, as described below;

- Figures 7, 8, 9, 9a, 9b show different views and cross sections of one possible type of bar/section B with a whole series of holes 30, 31, 32, 33 made following precise structural calculations. As noted above, only this element B forming part of a perimeter anchorage system is illustrated, specifying that the present invention extends its validity to any element that can be used to create a perimeter anchorage system for external connectors, in terms of shape, size, material and anything else that characterizes it. Figure 7 shows a side view of a bar/section B in which oval holes 30 located at predetermined distances can be seen, while Figure 8 shows the top view, from the narrow edge side of the structural panel, of a bar/section B with the holes 31, 32, 33 visible; the holes 31 and 33 are drilled in the upper part B3 of the bar/section B while the hole 32 is drilled in its lower part B2 aligned with the hole 31. Figure 9 shows a longitudinal section of the bar/section B of Figure 8, in which it is possible to observe the oval holes 30 laterally opposite the bar/section B, that is, made in the walls B l, and the hole 32 present at the level of its bottom B2 as already indicated. Figure 9a shows a cross- section of the bar/section B indicated in Figures 8 and 9, corresponding to the alignment of the oval holes 30 and the hole 33, while Figure 9b shows a cross-section of the bar/section B relative to Figures 8 and 9 corresponding to the alignment of the holes 32 and 31;

- Figures 10, 10a, and 10c show a possible type of joint 40 seen from a variety of perspectives, while Figure 10b is a cross section of that joint. In the joint 40 there are at least one hole 40b for the insertion and anchorage of a pin 41 shown in Figures 11 and 11a, and at least one threaded hole 40c or a hole having another suitable shape, for the connection of external connectors or joining systems with high ductility, and/or even traditional connectors if and where possible, as described below;

- Figures 12 and 12a show a ring-shaped elasto-plastic accessory material 42, which will be used at the sides of the joint 40, aligned with the hole 40b, while Figures 13 and 13a illustrate the adhesive membranes-caps 43 made of a suitable material and intended to be positioned on the outer sides Bl of the bar/section B where said oval holes 30 are located, as will be described later;

- the assembly of each single element of the perimeter anchorage system, consisting of said bars/sections B, joints 40, pins 41, rings 42, and caps 43, is simple and requires no special equipment. The assembly of a bar/section B is shown in Figures 14, 15 and 16. Figure 14 shows a view of a cross section of the bar/section B at the point where the oval-shaped side holes 30 are placed, at the level of the upper hole 33. The insertion of a joint 40 in the bar/profile B is obtained by inserting it, after bringing the elastomeric rings 42 on either side closer, through the hole 33. When the hole 40b, visible in Figures 10a and 10b, of the joint 40 with the two rings 42 positioned at its sides is aligned with the holes 30 made in the sides Bl of the bar/profile B, it engages the pin 41 from the outside of any of its sides Bl, until its head is flush with the opposite outer edge of said bar/section B; at this point both holes 30 are filled with the circular adhesive components 43, or components having another shape. Given that the adhesive is not present on the components 43 at the level of the hole 30 and the pin 41 inserted therein, at the time of the insertion and gluing of the bar/section B in its hollow portion L this method enables the longitudinal and rotational movement of the pin 41, which are necessary for the functions described below, without blocking them. Figure 15 shows a cross-section view of a bar/section B with a joint 40 inserted therein and having the elastomeric rings 42 at its sides, or alternatively compression springs, the pin 41 which hinges the joint 40 and the bar/section B and the two adhesive caps 43. As shown, the joint 40 has the possibility to move axially S with respect to the pin 41 thanks to the elastomeric material 42 used and to the width of the upper hole 33, made in the outer direction in the narrow edge of a CLT structural panel CI where the relative bar/section B is inserted. The ability to cover a clearly identified distance S allows the joint 40 to be easily centred when an external connector is connected to it; in addition, this sliding movement is useful to collaborate with the same joint if the structure is subjected to a violent movement, like an earthquake, contributing to the damping of the forces acting on the specific point in concert with the connector or joining system with high ductility connected thereto;

- if, as mentioned earlier, in combination and/or as an alternative to the use of the joints 40 provided to connect external connectors, joints already including specific connectors are used which can be rigid and/or flexible, these types of joints can be constrained, if deemed advantageous, to said bars/sections B, even after inserting said bars/sections B in the relative hollow portions L. Using these types of joints-connectors, further processing must be carried out on a panel CI, involving the creation of a series of holes, along all or part of the thickness of the panel CI itself, at the level of the various pairs of holes 30 present in the side walls Bl of said bars/sections B inserted in said panel CI where these joints-connectors are provided. This is possible since the holes 30 of said bars/sections B are free and protected only by the thin, easily drillable plugs 43, given that the joints 40 and the relative pins 41 are not present, and therefore it is possible to make these holes starting from either of the two sides, or faces, of the panel CI itself. In this way, after inserting through the hole 33 a joint equipped with the connector, in addition to any rings 42 as indicated for a joint 40, said pin 41 will be inserted through the aforesaid hole made from a plane surface of said panel CI . The pin 41 will be inserted through the first hole 30 of a first wall Bl of said bar/section B and shall constrain the joint-connector to the latter by being inserted into the hole 40b of the same after reaching the opposite outer edge of the wall B l passing through the second hole 30. To ensure that said pin 41 remains in its housing, that is, with its ends flush with the outer walls B 1 of the bar/section B and to enable said joint-connector to perform the same movements S as already indicated and R and SI as further described like a joint like the joint 40, the holes, or the hole - if made in only one side of the panel CI - is/are plugged with wooden pins with a diameter similar to that of the hole where the pin 41 itself was inserted. In this way it is also possible, if necessary, to extract said pin 41 and the related joint-connector constrained to it, in the case in which they must be replaced for any reason;

- Figure 16 shows a partial longitudinal section of a bar/section B with a joint 40 inserted therein which serves to connect an external connector. In this view it can be noted that the joint 40 is hinged to the pin 41 which in turn is inserted, on both opposite sides B l of the bar/section B, in the oval holes 30 as shown in Figure 15, and the hole 33 is in the upper part. Relevant features of this joint are provided by the fact that part of the joint 40 can move longitudinally SI with respect to the bar/section B thanks to the oval shape of the holes 30, in addition to its ability to rotate R around the axis of the pin 41 by a given number of degrees resulting from the width of the hole 33. Even this double movement S I and R of the joint 40 serves to easily centre the connection of an external connector and collaborate with it if the structure is subjected to a violent movement, such as an earthquake, contributing to the damping of the forces acting on the specific point in concert with the connector or joining system with high ductility connected thereto. In this view there is also a hole 32 which serves to allow a threaded bar 20 and/or the terminal portion 212 of the shaped bars 21 to pass therethrough, in order to anchor the bar/section B to the structural panel CI as will be described below;

- in order to insert, as shown in Figure 17, and fix a bar/section B complete with the joints 40 (and the relative accessory components 41, 42, 43) in a hollow portion L formed along a narrow edge of a CLT structural panel C, so as to obtain a CLT structural panel CI, the specific shaped bars 21 must first be inserted in the recesses N and holes Fl . This is done by introducing a predetermined amount of specific adhesive in the recesses N and in the holes Fl and then inserting the element 21 until it touches the bottom of the recess N. Particularly important, as already mentioned with reference to Figure 2, is the fact that the shaped bars 21 are inserted, and made integral by means of the adhesive used, in the layers of boards 2 and 4 orthogonally to them and this gives the assembly high resistance to extraction, which is difficult to achieve with a similar assembly made by means of connectors with a threaded cylindrical shaft. In any case, the present invention also extends its validity to any other possible process and nothing prohibits the use of connectors with a threaded cylindrical shaft to connect a bar/section B or other suitable element to the panel CI, but established data and time-tested experience have shown that the assembly as indicated above (threaded bar 20 and/or shaped bar 21 - special adhesive - wood) provides excellent performance resulting essentially from the fact that a homogeneous whole is formed, having better mechanical characteristics precisely at the points of union/bonding with respect to the rest of the wooden article in question. After applying a special adhesive and inserting all the fastening elements 21 in all the recesses N and holes Fl present in a narrow edge of the panel being processed, and allowing for the time necessary for the assembly wood-adhesive-elements 21 to set, first a given amount of special adhesive and immediately after the bar/section B (complete with the necessary joints 40 and the related accessories 41, 42, 43) are inserted into the hollow portion L, wherein the bar/section B is firmly attached to the panel CI, passing through the holes 31 with a socket spanner and using special bolts 22, to the ends 212 of said shaped bars 21. After fixing, as shown in Figure 17, the bar/section B is perfectly aligned with the narrow edge of the CLT structural panel CI and is centred inside the hollow portion L with respect to the thickness of the panel CI itself. A similar operation is performed on the opposite narrow edge of the CLT structural panel CI so that both sides are equipped with an anchoring system consisting of bars/sections B equipped with joints 40 (and relative accessory components 41, 42, 43), fixing elements 21, and bolts 22, in addition to the adhesives used to homogenize the assembly;

- the same operation, namely fixing the bar/section B in the hollow portion L formed along one of the two narrow edges, adjacent to that of Figure 17, of a CLT structural panel C, in order to obtain a CLT structural panel CI, is performed as illustrated in Figure 18. In this case, the threaded bars 20 are inserted in the holes F made in the bottom of the hollow portion L after applying a well-determined amount of specific adhesive. Particularly important, as already indicated in relation to Figure 17, is the fact that the threaded bars 20 are inserted in the layer of boards 3 orthogonally and made integral with it by the adhesive used, and this gives the union high resistance to extraction, which is difficult to attain with a similar union made of connectors with a threaded cylindrical shaft. After applying a special adhesive and inserting all the threaded bars 20 in all the holes F formed in a hollow portion L of a narrow edge of the panel being processed and allowing for the time necessary for the assembly wood-adhesive- bars 20 to set, the bar/section B is inserted into the hollow portion L. The operation involves the application of a certain amount of special adhesive in the hollow portion L, followed by the immediate insertion of the bar/section B (equipped with the necessary joints 40 and the related accessories 41, 42, 43), which is firmly attached to the panel CI, passing through the holes 31 with a socket spanner and using special bolts 22, to the threaded bars 20. After fixing, as shown in Figure 18, the bar/section B is perfectly aligned with the narrow edge of the CLT structural panel CI and is centred inside the hollow portion L with respect to the thickness of the panel C 1 itself. A similar operation is performed on the opposite narrow edge of the CLT structural panel CI so that both sides are equipped with an anchoring system consisting of bars/sections B including joints 40 (and the relative accessory components 41, 42, 43), fixing elements 20, and bolts 22, in addition to the adhesives used to homogenize the assembly;

- the outcome of the operations described so far is shown in Figure 19, a longitudinal section of a CLT structural panel CI complete with a perimeter anchorage system on all four sides. This structural panel will have all four sides where bars/sections B are used, complete with the joints 40 (and the related accessories 41, 42, 43), firmly fixed to the wooden panel by specific adhesives and mechanically to the components 20 and 21, which are distributed at distances established by precise structural calculations along the entire perimeter of the CLT structural panel C 1. A CLT structural panel C 1 equipped with a perimeter anchorage system which is the subject of the present invention can have four linear elements B, or elements B having any other suitable shape and size, inserted in its four sides. Essentially, in the same CLT structural panel CI there can be elements developing longitudinally, forming part of a perimeter anchorage system, of the same type, or there can be combinations of types, as well as of the same or different lengths, diameters, thicknesses, shapes, position and nature of the materials used. With reference to the length of one or more longitudinal elements B inserted in a panel CI, it is possible that its length, and that of the relative hollow portion L, can also be less than that of any of the narrow edges where said elements B are located: moreover, said length of one or more of said elements B may be greater than that of the relative edge X, Y and therefore exceed the length of one or more sides of the panel CI itself. Another detail is constituted by the fact that the longitudinal elements used, in this case bars/sections B, may, at the corner points where they may meet, be detached or joined together. In practice, always during the assembly process, or even subsequently if considered advantageous, components (not shown) can be used that allow the various elements - bars/sections B - to be joined together, integrally or not, to form a closed ring which in certain cases may be structurally advantageous. A CLT structural panel CI may however not necessarily be equipped on each side thereof with elements B developing longitudinally or other suitable elements, and this is due to the use of a structural panel CI in a given structure;

- Figure 20 shows a partial view of a narrow edge of a CLT structural panel C 1 equipped with a perimeter anchorage system. In this view it is possible to note the perfect centring of the joints 40 with respect to the thickness of the structural panel CI and the fact that they can move, both longitudinally and transversely, relative to the bar/section B as described above. As already mentioned, the longitudinal centre-to-centre distance between the joints 40, as well as their size and shape, is determined by precise structural calculations and therefore it is established that in this type of narrow edge of a CLT structural panel CI the joints 40 are not necessarily always positioned at equal distances, as ,for example, in the case of use of this structural panel C 1 as vertical, horizontal or tilted wall or floor. Figure 20 also shows the hole 31 where it is possible to see a bolt 22, positioned at the bottom B2 of the bar/section B, which is used to secure the bar/section B to the CLT structural panel C 1 by means of the threaded bars 20;

- Figure 21 shows a partial view of a second narrow edge, orthogonal to that shown in Figure 20, of a CLT structural panel CI equipped with a perimeter anchorage system. The perfect centring of the joints 40 with respect to the thickness of the structural panel CI and the fact that they can move, both longitudinally and transversely, relative to the bar/section B as described above can also be seen in this view. Also on this side the longitudinal centre-to- centre distance between the joints 40, as well as their size and shape, is determined by precise structural calculations and therefore it is established that even on this type of narrow edge of a CLT structural panel CI the joints 40 are not necessarily always positioned at equal distances, as, for example, in the case of structural panels used for vertical, horizontal or tilted walls or floors. Figure 21 also shows the hole 31 where it is possible to see a bolt 22, positioned on the bottom B2 of the bar/section B, which is used to secure said bar/section B to the CLT structural panel CI by means of the ends 212 of the shaped bars 21;

- finally, Figure 22 shows, in perspective and in cross section, a portion of a CLT structural panel CI equipped on two contiguous narrow edges with two bars/sections B where there are joints 40 constrained to said bars/sections B by means of pins 41 and where said joints 40 are present at the level of the holes 33 in order to allow the connection of external connectors. This view also shows the system by which said bars/sections B are firmly anchored to the panel CI and according to which each is inserted in the relative hollow portion L after applying a specific adhesive and is permanently fixed to the threaded bars 20 and shaped bars 21 by means of nuts 22, in turn firmly fixed by means of a specific adhesive;

- a CLT structural panel CI equipped with a perimeter anchorage system for external connectors can also be composed of multiple side-by-side and parallel longitudinal anchorage elements, such as bars/sections B, or in any case elements having any other suitable form, when a certain kind of structural panel is composed of more than five layers of boards laid crosswise with respect to each other. If a CLT structural panel CI is made up of, for example, seven or more layers of boards laid crosswise with respect to each other, there may also be two or more perimeter anchorage elements B present on a single side, arranged in parallel, or even a single one that involves multiple layers of boards with respect to what is described for a five- layer structural panel. If the perimeter anchorage elements, bars/sections B or other suitable elements, involve a number of boards greater than a five-layer CLT type wood structural panel CI, all components and processes described may be different from those discussed thus far, in terms of quality, type, quantity, form, proportions, number, joining modes and more. In any case, regardless of the solution adopted and necessary, the manufacturing process is always similar to that already described and, therefore, feasible at an industrial level;

- similarly to the construction of a flat CLT structural panel CI, it is also possible to construct curved CLT type wood panels with a perimeter anchorage system, adopting specific processing methodologies without prejudice to the final result, and that is the provision of a perimeter anchorage system for external connectors on one or more of its sides.

Description of the drawings

Figure 1 shows a normal CLT type structural panel C currently produced and available on the market. Figure 2 shows a normal CLT type structural panel C with specific milled portions L, recesses N, and holes Fl on at least one edge thereof. Figure 3 shows a normal CLT type structural panel C with specific milled portions L and holes F on an edge adjacent to the previous one. Figure 4 shows a normal threaded bar 20 made of iron or a similar material. Figure 5 shows a shaped bar 21 with at least two legs 211 and at least one threaded connection 212, made of iron or a similar material. Figure 5a shows a side view of Figure 5. Figure 5b shows the top view of Figure 5. Figure 6 shows a bolt 22 made of iron or a similar material. Figure 7 shows a partial side view of an element B with longitudinal development forming part of the anchorage system, made of any suitable material. Figure 8 shows a top view of Figure 7. Figure 9 shows a longitudinal section of Figure 7. Figure 9a shows a cross section of Figure 7. Figure 9b shows another cross section of Figure 7. Figure 10 shows a view of a type of joint 40 which can be used to form an anchorage system. Figure 10a shows a different view of Figure 10. Figure 10b shows a section of Figure 10a. Figure 10c shows another view of Figure 10. Figure 11 shows a pin 41 made of steel or another suitable material. Figure 11a shows a view of Figure 11 from another angle. Figure 12 shows a ring 42 made of an elasto-plastic material or the like. Figure 12a shows a view of Figure 12 from another angle. Figure 13 shows a thin cap 43 made of any suitable material, with one side partially coated with adhesive. Figure 13a shows a view of Figure 13 from another angle. Figure 14 shows a cross section of Figure 7. Figure 14a shows the component of Figure 10 during the assembly of the perimeter anchorage system. Figure 14b shows the component of Figure 12a during the assembly of the perimeter anchorage system. Figure 14c shows the component of Figure 12a during the assembly of the perimeter anchorage system. Figure 14d shows the component of Figure 11 during the assembly of the perimeter anchorage system. Figure 14e shows the component of Figure 13a during the assembly of the perimeter anchorage system. Figure 14f shows the component of Figure 13a during the assembly of the perimeter anchorage system. Figure 15 shows a joint 40 as shown in Figure 10 and the relative accessory components 41, 42, 43, assembled in the body of a longitudinal element B of Figure 7. Figure 16 shows a longitudinal section of Figure 15. Figure 17 shows a partial cross section of a structural wooden panel CI equipped with a perimeter anchorage system. Figure 18 shows a second partial cross section of a structural wooden panel CI equipped with a perimeter anchorage system. Figure 19 shows a longitudinal section of a structural wooden panel CI equipped with a perimeter anchorage system. Figure 20 shows a partial view of a narrow edge of a structural wooden panel CI equipped with a perimeter anchorage system. Figure 21 shows a partial view of a second narrow edge of a structural wooden panel CI equipped with a perimeter anchorage system. Figure 22 shows a perspective and sectional view of a portion of a CLT structural panel CI equipped with a perimeter anchorage system on two contiguous narrow edges.

Implementation of the invention

A CLT type structural panel CI which comprises a perimeter anchorage system, being perfectly compatible as regards shape and size with any standard CLT type structural panel, can be used in conjunction with any analogous type of panels, those already defined as standard, reinforced CLT type structural panels, and also with other materials used and useable in construction. As already indicated in the "description" section, a structural wooden panel made of multiple layers of boards where each layer of boards is placed crosswise with respect to the adjacent layer, can be constructed using specific adhesives, aluminium nails or wooden dowels as a joining system between the various layers. For this reason, irrespective of the method used to join the various layers of boards that make up this type of panel, the present invention can be adopted on any of them, and consequently also extends its validity irrespective of the technical and/or commercial name adopted. A CLT type structural panel CI was specifically designed in order to construct buildings of any type having improved anti-seismic properties compared to those achievable with standard CLT type panels, given the possibility to use connectors or joining systems having high ductility characteristics. Moreover, as already mentioned, the use of specific connectors or joining systems with high ductility is intended to reduce, if not completely eliminate, the use of fastening components typical of wood carpentry, such as nails, screws, brackets, pins and the like. Unlike what happens today in the design of a given building, where particular attention must be given not only to the number, type and arrangement of the necessary connectors (sometimes tens or hundreds of thousands), the use of a CLT type structural panel C 1 equipped with a perimeter anchorage system for external connectors allows a more rapid and reliable design, because its mechanical characteristics, as well as its behaviour in combination with the specific connectors usable, already available or to be developed in the future, are already known with good accuracy. Another significant aspect is the worksite assembly stage, in which, given the reduced number of connection components to be used, but especially the fact that they cannot be connected the wrong way, contrary to what can happen when using typical traditional carpentry methods, the assembly is reliable and meets the specifications set out in the design stage, so that the resulting buildings have structural characteristics which comply exactly with the calculations and simulations performed by the designer. No less important is the NDD (No Damage Design) design criterion adoptable, that is, design to prevent damage, specifically as a result of violent natural phenomena such as earthquakes. The use of connectors and/or joining systems having high ductility enables the design and construction of buildings that actually meet this criterion (NDD), which is much more complex when using traditional connection methods such as nails, screws, brackets, pins and the like. In practice, given that a CLT type structural panel CI including a perimeter connection system is an element to be considered almost infinitely rigid, when an event occurs that tends to cause panels to detach and/or move, the forces are not concentrated in a specific point or localized in small areas, as in the case of joints with screws and/or nails, but are distributed simultaneously over a wider area of the structural panel CI as a result of the integral union between the various layers of boards that comprise it, the threaded bars and/or shaped bars inserted firmly in its body, and the perimeter anchorage elements present on its edges, as well as a result of the action of the joints used. In this way, by suitably calibrating a hierarchy of deformation and breaking of the connectors and/or joining systems with high ductility, the CLT type panels CI which are the subject of the present invention are not subjected to localized stresses, since virtually all the energy produced, for example, by an earthquake, is absorbed and dissipated by the high- ductility connectors or joining systems used, in concert with the entire anchoring system devised.

In summary, the use of a CLT type structural panel C 1 with a perimeter anchorage system has many advantages, including greater simplicity in the design and construction of buildings with improved earthquake resistance with respect to that obtainable through the use of standard CLT panels and traditional connectors, a factor which is certainly more important than any other, including of an economic nature, if this enables the safeguarding of people in the case of violent natural phenomena.

Therefore, with reference to the preceding description and the attached drawings, the following claims are expressed.

Claims

1. Structural wooden panel of the CLT type (CI), that is, structural wooden panel of the CLT type (C), also called XLam, comprising three or more superimposed layers (1, 2, 3, 4, 5), each formed by several boards adjacent to each other and arranged in the same direction (X, Y), wherein each layer (1, 2, 3, 4, 5) is arranged with the boards laid crosswise with respect to the boards of the opposite layer, characterized in that it comprises, on one or more of its narrow edges, at least one perimeter anchorage system, in turn comprising:

• at least one milled or hollow portion (L) created along at least one edge of said structural panel (C);

• a plurality of recesses (N) and/or holes (Fl, F) made and distributed on the bottom of said hollow portion (L), and wherein said holes (Fl, F) are provided at the level of at least one layer of boards (2, 4, 3) substantially crosswise in relation to the direction (X, Y) of the boards;

• at least one threaded (20) and/or in any way shaped bar (21) inserted and constrained in each one of said recesses (N) and/or said holes (Fl, F);

• at least one element, bar or section (B) developing longitudinally, housed and constrained firmly in said hollow portion (L) and constrained to said bars (20, 21) and thus to said finished structural panel (CI),

and wherein a plurality of joints (40) are distributed along said element (B) developing longitudinally and constrained to it, wherein said joints (40) are used to connect external connectors in general suited, not exclusively, to join said panels (CI) to any other structural element.

2. Structural wooden panel of the CLT type (CI) according to claim 1, characterized in that each one of said joints (40) is constrained to said element (B) developing longitudinally in a movable way with respect to the same element (B) developing longitudinally, being able to carry out translation movements crosswise (S) and/or in the longitudinal direction (SI) and/or rotary movements (R) with respect to said element (B) developing longitudinally.

3. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that it comprises, on a first pair of narrow edges opposing each other, part of said perimeter anchorage system, and wherein each one of said edges in turn comprises: • said milled or hollow portion (L) created along the edge of said structural panel (C);

• a plurality of said recesses (N) created and distributed on the bottom of said hollow portion (L);

• for each recess (N), at least one pair of said holes (Fl) made at the level of the two layers of boards (2, 4) arranged parallel to said hollow portion (L), and wherein said holes (Fl) are arranged crosswise with respect to the main direction of said boards (2, 4);

• at least one of said shaped bars (21) inserted in each recess (N) and the corresponding pair of holes (Fl), and wherein said shaped bar (21) in turn comprises at least one leg (211) with genetically corrugated or knurled or in any way shaped surface suited to be engaged in each one of said holes (Fl), and at least one threaded or shaped connection (212) for fixing said element (B) developing longitudinally that is housed in said hollow portion (L).

4. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that it comprises, on a second pair of narrow edges opposing each other and orthogonal to those mentioned above, another part of said perimeter anchorage system, and wherein each one of said edges in turn comprises:

• said milled or hollow portion (L) created along the edge of said structural panel (C);

• a plurality of holes (F) made and distributed along the bottom of said hollow portion (L), at the level of a layer of boards (3) arranged parallel to said hollow portion (L), and wherein said holes (F) are arranged crosswise with respect to the main direction of said boards (3);

• at least one of said threaded bars (20) inserted in each hole (F), and wherein said threaded bar (20) is in turn suited to fix said element (B) developing longitudinally that is housed in said hollow portion (L).

5. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said shaped bar (21) has legs (211) with generically rectangular cross section substantially corresponding to the cross section of the respective insertion holes (Fl).

6. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said threaded bars (20) and/or said shaped bars (21) can be made of any suitable material, even of a non homogeneous nature.

7. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said threaded bars (20) and/or said shaped bars (21) can have shapes and dimensions that may be different from those shown and non homogeneous.

8. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said threaded bars (20) and/or said shaped bars (21) can be positioned in the respective recesses (N) and/or holes (Fl, F) at longitudinal distances, even different from each other, along any edge of a structural wooden panel of the CLT type (CI) and on each side of the panel (CI).

9. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said element, bar or section (B) developing longitudinally in turn comprises:

• a substantially box-shaped body, with side walls (Bl) and bottom (B2) suited to be laid on the bottom of a hollow portion (L) and an upper wall (B3) opposite said bottom (B2) and said bottom of the hollow portion (L);

• a plurality of oval or slotted holes (30) distributed in aligned and corresponding positions along the two side walls (Bl) of said element (B) for the insertion of pins (41) suitable for coupling said joints (40) and/or other suitable types of joints already complete with the relative connectors;

• a plurality of holes (32) distributed along said bottom (B2) of said element (B) for the insertion of the coupling ends (212) of said shaped bars (21) and/or threaded bars (20) firmly driven in the structural panel (CI);

• a plurality of holes (33) distributed along said upper wall (B3), in a position corresponding to said pairs of oval or slotted holes (30) for the insertion of said joints (40) and of other suitable types of joints, so as to allow the connection of external connectors to said joints (40);

• a plurality of holes (31) distributed along said upper wall (B3), in a position corresponding to said holes (32) of said bottom (B2) in order to fix said bar/section (B) to said bars (21, 20) driven in the structural panel (CI) by means of nuts (22) or other suitable fixing means.

10. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that each one of said joints (40) comprises: • a body suited to be inserted in said element (B) developing longitudinally;

• at least one through hole (40b) suitable for the insertion of a pin (41) or suitable constraining element for anchoring said joint (40) to said element (B) developing longitudinally;

• at least one threaded or not threaded hole or seat (40c) in any way suitable for the connection of external connectors in general.

11. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that each one of said joints (40) is constrained to said element (B) developing longitudinally by means of at least one pin (41) or suitable constraining element, and wherein said pin (41) is inserted with its two ends in two corresponding oval or slotted holes (30) made in the side walls (Bl) of said element (B) developing longitudinally, and wherein at least one elastic means (42), a washer in an elastomeric material, a compression spring or another element is advantageously placed on both sides of each joint (40) and interposed between the joint (40) and said side walls (B l) of the element (B) developing longitudinally, in order to allow said joint (40) to perform said translation movements crosswise (S) and/or in the longitudinal direction (SI) with respect to said element (B) developing longitudinally and/or partially rotary movements (R) around said pin (41).

12. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that it comprises closing elements or plugs (43) suited to be applied externally to said side walls (B l) of the element (B) developing longitudinally, so as to close said oval or slotted holes (30), after the insertion of said joints (40) and of the relative accessory elements (41, 42) and even when the joints inserted therein are of any type different from said joints (40), and before the insertion of said element (B) developing longitudinally in the corresponding hollow portion (L).

13. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that in proximity to one or more of its angles said shaped bars (21) inserted in a narrow edge are crossed with said threaded bars (20) inserted in the adjacent narrow edge, wherein said threaded bars (20) may be interposed between said legs (211) of at least one shaped bar (21).

14. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that all the four edges of said structural panel (CI) comprise at least one or more of said perimeter anchorage systems.

15. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said elements (B) developing longitudinally, when they are present on the four edges of said structural panel (CI), can be generically joined to each other in a rigid or non-rigid manner so as to form at least one closed ring.

16. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that not necessarily all the four edges of said structural panel (CI) comprise at least one or more of said perimeter anchorage systems.

17. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said element (B) developing longitudinally and the relative hollow portion (L) can be as long as or shorter than the corresponding side (X, Y) of the structural panel (CI) and/or be divided longitudinally even in several sections, and wherein the longitudinal section or element (B) can be longer than the corresponding hollow portion (L) obtained on any narrow edge of said panel (CI), and even project from the latter.

18. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said element (B) developing longitudinally can have, in the same structural panel (CI), different shapes, for example rectangular, round, square or other suitable shapes, and furthermore can be solid or not solid.

19. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that said element (B) developing longitudinally can be provided or not with joints (40) and/or other suitable types of joints, and at the same time comprise or not a plurality of threaded or non-threaded holes made in any useful direction and/or other types of couplings or constraining elements suitable for the connection of external connectors.

20. Structural wooden panel of the CLT type (CI) according to the preceding claims, characterized in that it is curved.

21. Method for providing a perimeter anchorage system on a structural wooden panel of the CLT type (C), also called XLam, meaning a panel comprising three or more superimposed layers (1, 2, 3, 4, 5), each one formed by several adjacent boards arranged according to the same direction (X, Y), wherein each layer (1, 2, 3, 4, 5) is usually arranged with boards laid crosswise with respect to the boards of the opposite layer, characterized in that it comprises the following stages:

• creating milled-hollow portions (L) on at least one of the four narrow edges of said structural panel (C);

• creating a plurality of milled portions-recesses (N) and/or holes (Fl) on the bottom of said hollow portions (L), obtained on at least one of the two opposite narrow edges of said panel (C) where the layers of boards (2, 4) are parallel to said edges;

• creating a plurality of holes (F) on the bottom of said hollow portions (L), obtained on at least one of the other two opposite narrow edges of said panel (C) where the layer of boards (3) is parallel to said edges;

• inserting the corresponding threaded bars (20) and/or shaped bars (21) in said holes (F and/or Fl) and/or recesses (N);

• inserting elements developing longitudinally, bars/sections (B) in said hollow portions (L), said elements, bars/sections being complete with joints (40) and/or any other suitable type of joint, and accessory materials like pins (41), rings in an elasto-plastic material (42) and caps (43) that are complementary and functional to said joints (40);

• firmly fixing said bar/section (B) made up as described to said bars (20, 21) by means of nuts (22) or other suitable constraning means,

thus obtaining a structural wooden panel of the CLT type (CI) complete with a perimeter anchorage system for external connectors suited to join said structural panel (CI) to other structural and non- structural elements.

22. Method according to the preceding claim, characterized in that it comprises the cleaning of said hollow portions (L), recesses (N) and holes (F, Fl) through a suction system before the introduction of a specific adhesive.

23. Method according to the preceding claims, characterized in that it comprises the step of introducing a specific adhesive in said hollow portions (L), recesses (N) and holes (F, Fl) before the introduction of the corresponding required components (B, 20, 21).