More in detail the invention refers to a step component of the said kind, specifically designed for the construction of sports facilities, but equally usable for grandstands of performance halls or meeting halls, provided with a cover or not.

As is well known, at present the realization of the grandstands of sports facilities involves the use of prefabricated modules, normally made of reinforced concrete, which define the so-called steps, on which seats are eventually placed or simply on which seatings are defined.

These prefabricated reinforced concrete modules are usually positioned on a main supporting structure also made of reinforced concrete or steel or other materials. The supporting structure is typically constituted by columns or vertical walls that support in turn inclined beams on which the modules of reinforced concrete are positioned and fixed. The inclined beams are usually parallel and placed at an interdistance of between 6 and 12 m, even if the interdistance between two adjacent inclined beams is established according to requirements.

The prefabricated modules have a predefined shape, in particular a predefined cross section, which can have the form of a L, Z, or even C or Ω, and are designed and manufactured to support both their own weight and the weight of the spectators that will be above them while participating in an event. The cross section should also be designed to meet certain criteria of deformation caused by vibration, in order to ensure comfort and safety for the spectators that take place on the grandstands. For example, the horizontal portion or "tread" of the steps may be slightly inclined to facilitate drainage or run-off of rainwater, as well as to facilitate cleaning of the grandstands at the end of an event. Said tread must also be conceived so as to define a space for the seatings (or, in case, for the seats) and a corridor walkway to the rear of the seatings or seats, serving for the passage of spectators directed to the seatings or seats in the next row, or arranged after the step, or after and superiorly. The vertical portion (or the vertical portions) or "riser" of the steps constitutes the rear (or front or front and rear) or the support of the step and on it are generally fixed brackets for fastening the seats.

The solutions known in the state of the art that make use of prefabricated reinforced concrete modules present different problems and disadvantages.

A first notable drawback relates to the own weight of the prefabricated modules which usually corresponds to about 2500 kg/m ³ . Such a weight per unit of volume requires the realization of an adequate support structure, with remarkable increase of the related costs and of the realization time. In fact, in case a support structure is realised also made of reinforced concrete, adequate curing time must be provided. Furthermore, individual forms should be arranged in which the concrete is poured in the fluid state. Another disadvantage due to the high weight of the prefabricated reinforced concrete modules is related to the difficulty of movement of said modules, for which appropriate equipment (cranes and/or trucks of considerable size) is necessary which involves a cost of using that is considerable and often too high. Always with reference to the solutions that make use of prefabricated reinforced concrete modules, amongst the additional problems and disadvantages typical of these solutions the dangers arising from the realization of stands of this type in areas with a high earthquake risk should be cited. Again, the prefabricated reinforced concrete modules involve further problems when additional equipment must be attached on the steps of the stands made with said modules, such as seats, booster seats or similar. In fact, the installation of the seats requires the anticipated drilling of the modules in predefined positions as well as the use of dowels or chemical bolts for the fastening of the support plates of the seats to the steps; the precision required for the definition of the points of drilling involves, however, a considerable expenditure of time, with a corresponding increase of the costs involved. The same applies to the application of dowels or chemical bolts in the perforations or drilled holes.

In the state of the art solutions are also known for the construction of stands for sports facilities which use materials other than concrete, such as steel, galvanized or painted iron and/or similar materials.

However, these solutions also have significant disadvantages and problems. For example, solutions are known that make use of components such as pipes, joints, junctions or other, quite similar to those used for the construction of scaffolding. These solutions, however, do not offer neither security nor even the requested convenience, and are often unacceptable due to their aesthetic appearance being very coarse. Other solutions that make use of steel and/or iron and/or similar metals have not resulted in a satisfactory way to overcome the drawbacks typical of solutions made of reinforced concrete. Many of these solutions present the same problems in terms of poor ease of handling, their excessive weight, assembly difficulties and final appearance that is not satisfactory. Among the various solutions known in the state of the art that make use of components in steel or iron or similar metals those described in the documents U.S. 7,047,699, U.S.

5,159,788 and WO2010/028476 , U.S. 2006/150540 Al and GB 2 463 445 A and, in particular in the application PCT/IB2011/055902 , can be mentioned.

The application PCT/IB2011/055902 describes a step in steel, for the realization of grandstands of stadiums and more generally of sport facilities, consisting of two slabs of steel, 3 mm thick, and intimately connected and spaced by means of pressure folded steel profiles, 2 mm thick. These profiles can have different form, for example like a C, Z, Ω. A step thus carried out, with a distance between the lower plate and the higher plate of about 10cm, has the ability to support, on a structural bay variable between 6 and 12m, the average number of 2 people per linear meter (a place every linear 50cm of the step) , including live loads and dynamic loads (spectators jumping at different frequencies) .

The solution according to the application PCT/IB2011/055902 in practice allows to create steps with ease, using techniques and materials common to most of the factories of medium size, without the need for production machinery available to only large industrial plants. This type of approach with semi craft technique avoids the need for a strong initial investment for the production, required instead for example by the patent US 7,047,699 B2 , according to which the bottom plate and the top plate are connected by a thickness of extruded polymeric material and for the realization of which requires a high initial investment, due to production of the element in a chain of industrial type.

According to further prior art solutions, moreover, are proposed other types of solutions, all united by the need to lighten and to dispose the material in more advantageous geometric positions. According to the teachings of the patent application WO 2010/028476A1, for example, the lower and the upper plate are spaced and intimately connected by vertical plates of the same material. In this case also, the realization of the modules is entrusted to a method of industrial type, because the material is made by extrusion.

In recent years, it is increasingly spreading the choice to realize polyfunctional sports facilities, inside which there are other structures, such as gyms, museums, commercial spaces and even schools, housed beneath the grandstands. In all these cases, in particular, it is exploited the space below the grandstands. The latter, accordingly, also constitute the coverage of these structures. Consequently, the need to make the grandstands with features that ensure a good thermal insulation, in order to avoid energy waste. The behavior of the steel structures with regard to the thermal insulation is rather poor and the solutions already seen previously, which included the use of a filler in polymeric material extruded between a plate and the other of each step, do not contribute if not in small part to improve this parameter. In fact, the characteristics sought in the previously said polymeric materials were those structural, and not those of insulation. Not only that, the structure of the steps according to the prior art is also such as to generate the appearance of different thermal bridges which nullify the effectiveness of any insulation system. The lack of thermal insulation also involves the possibility that, when the temperature is cold, under the grandstands or on the ceiling of the underlying structures, condensation of water vapor occurs and said condensation may compromise the aesthetics of the interior linings of these structures. This type of problem, particularly felt in countries with cold climates, but not only there, requires the realization of particularly expensive expedients.

On the other hand, a further problem severely limits the use of steps made of steel even in particularly hot countries. In fact, in hot climates the steel steps are subjected to overheating as a result of solar radiation. Discomfort of use follows, the spectators being forced to suffer the heat if not to risk burns from contact with these surfaces. To overcome this problem, it has been proposed according to the prior art to coat the steps with thick layers of paints of light colors, with the function both to reflect the incident radiation, and to constitute a sort of insulation that covers the outer surface of the steps. Alternatively, in countries with hot climates, the problem has been addressed abandoning the use of steps made of steel to the advantage of the more traditional steps in reinforced concrete.

Exposure to changing thermal conditions, then, involves a further technical problem related to the use of steps made of steel, which consists in the thermal expansions which the metals more than other materials are subjected to. To avoid that, dilating, the steps go to push on each other, with the possibility of compromising the hooking of the steps themselves to the support structure below, during assembly of the grandstands with steps made of steel, an interspace for expansion is left between a step and the following one. However, these interspaces, typically of the order of one centimeter, for the entire section of the step, constitute channels for water passage, which, infiltrating, can compromise the structure (formation of rust) or lead to flooding of the premises underlying the grandstand. To prevent the passage of water through the interspaces for expansion present between adjacent steps, according to the prior art different sealing systems have been proposed, all rather complicated in construction, because of the space that must be left at the disposal of the considerable thermal expansion of the steps, requiring complicated devices to prevent the passage of water.

Not only that, the steps made of steel have another problem that has so far limited the application. It is in fact known that the steel structures are poorly resistant to high temperatures: 800 °C reached, the steel passes immediately from elastic phase to plastic phase, collapsing. This structural problem of the steel can be only partially solved in different ways. For example, in Italy, where the steel is hardly used in construction, generally trying to protect it with fire retardant foam or plasterboard linings. On the contrary in the Anglo- Saxon Countries, which make widespread use of steel structures, the protection of the structure against the risks associated with poor strength of steel at high temperatures is delegated to measures mainly related to the evacuation and the use of automatic fire- extinguishing systems.

It is therefore evident that the problem due to poor heat resistance of steel structures can be said still to be not perfectly solved.

In light of the foregoing, it is therefore still unsolved the problem of proposing a step for a grandstand structure that is lighter than the traditional steps in reinforced concrete and that at the same time is simple to realize, without requiring high costs due to the need to resort to large industrial production plants, and without all the technical problems of the structures made of steel previously seen.

In this context it is included the solution according to the present invention, which aims to overcome the drawbacks mentioned above and encountered in the known solutions in the state of the art. In particular, the aims and objectives of the present invention can be summarized as follows.

Proposing a solution relating to a module for the construction of stands comprising steps which is both of low weight, which is therefore easy to handle, which is self-supporting, durable and able to withstand adequate loads, which presents a reduced thermal transmittance , which can be realised in a simplified manner and at low cost, which is easy to mount, ie is mountable by means of relatively simple and fast operations and therefore at low cost, which is easy to handle (to lift, to transport, etc..) , which is resistant to high temperatures, which both looks nice outside and compatible with the aesthetic requirements of structures grandstands of sports facilities and/or performance halls or meeting halls, provided or not with coverage, of a certain prestige, which offers appropriate safeguards in terms of safety and comfort of the audience. A further object of the present invention is therefore to provide a solution that enables the realization of a prefabricated module for the realization of grandstands of sports facilities and/or performance halls or meeting halls which can be accomplished through the use of traditional materials and also processed by hand. A further object of the present invention is to suggest a form of default shape and size, which is therefore interchangeable and usable for the realization of grandstands of different sizes. The shape of the module according to the present invention should also allow to mutually bind two adjacent steps in a simple and fast way and without requiring the use of special and expensive anchoring means .

The module will also have to be producible in different formats depending on the needs and or circumstances and without the change of format involving drastic and important changes in the production and/or realization process. These and other results are obtained according to the present invention by proposing a step component, in particular for a grandstand structure, realized with an innovative material for this type of use and that, in addition, is completely self-supporting.

In particular, according to the present invention, it is proposed a step component made of laminated wood. This type of material, compared to the advantages already known to a person skilled in the art, to date has seen its application limited to the field of covering. The purpose of the present invention is to apply this same type of material also to the realization of self-supporting step components for easy to assemble grandstands.

It is known that laminated wood is a structural material produced by gluing of boards of wood in turn already classified for structural use.

The laminated wood is, therefore, a composite material, consisting essentially of natural wood, of which it maintains the advantages (including in particular the high ratio between mechanical strength and weight and good behavior in case of fire) , but it is also a product that can be realized on an industrial scale, that, through a technological process of pressure glueing, reduces the defects typical of solid wood.

Stages of production consist in reducing the trunk to slats, said slats, usually of a width not exceeding 20cm (to prevent excessive deformation caused by the phenomenon of withdrawal) and their reconstruction by gluing .

It is possible to produce elements of the desired shapes and sizes, without the limits arising from the size of the tree; moreover the limit in length of a beam made of laminated wood is mainly given by the possibility of transport and installation of the same.

The purpose of the present invention is therefore to provide a step component, in particular for a grandstand structure, which allows to overcome the limitations of the solutions of the prior art and to achieve the previously described technical results .

Further object of the invention is that said step component can be manufactured with substantially low costs, both as regards production costs and as regards management costs .

Another object of the invention is to provide a step component which is substantially simple, safe and reliable.

It is therefore a specific object of the present invention a step component made of laminated wood, in particular for a grandstand structure, aimed at the making of sport facilities, performance halls or meeting halls, by way of arranging and fixing to an underlying supporting structure, said step component being self-supporting and possibly comprising a L- shaped structure, or comprising a first horizontal portion or tread, comprising an elongated substantially rectangular surface and a thickness being significantly smaller than the sides of said surface, and a second portion or riser, arranged perpendicularly to said first portion and extending from one of two long sides of said first portion, upwards, or said step component being self-supporting and comprising a Z- shaped structure, or comprising a first horizontal portion or tread, comprising an elongated substantially rectangular surface and a thickness being significantly smaller than the sides of said surface, and two second portions or risers, arranged perpendicularly to said first portion and extending from both long sides of said first portion, respectively upwards a first riser and downwards a second riser.

By the expression "shaped", here and all along the description and claims of the present patent application, ot isdesignated the cross section of the step component .

Preferably, according to the invention, in correspondence of a free end portion of said riser of said step component comprising a L-shaped structure, or in correspondence of a free end portion of said riser extending upwards of said step component comprising a Z-shaped structure, a first engagement portion is provided.

Moreover, according to the invention, in correspondence of a free end portion of said tread of said step component comprising a L-shaped structure, or in correspondence of a free end portion of said riser extending downwards of said step component comprising a Z-shaped structure a second engagement portion is provided, deputed to engage with said first engagement portion of a second step component, comprising a L- shaped structure, or with said first engagement portion of a second step component comprising a Z-shaped structure, arranged below said step component.

Preferably, according to the invention, said engagement portions have a rising structure going from the outside towards the inside of the grandstand structure and still more preferably comprise such a structure that present, going from the outside towards the inside of the grandstand structure, a rising flyer. Still, always according to the invention, said step component comprises holes for the passage of pins provided with a threaded end, arranged in positions corresponding to those of respective holes of said supporting structure.

Possibly, according to the present invention, said step component can be treated against weathering and/or can be made of reinforced laminated wood.

Finally, always according to the present invention, said step component can be made as a single element.

The present invention will be described, for illustrative, non limitative purposes, according to its preferred embodiments, making reference in particular to the figures of the enclosed drawings, wherein:

- figure 1 shows an axonometric view of three step componets according to a first embodiment of the present invention, made according to a L- shaped structure, comprisinf a supporting understructure in steel;

- figure 2 shows a cross section view of the three step components of figure 1, with reference in particular to the system for fixing to an understructure made of steel,

- figure 3 shows a detail of the cross section view of the three step components of figure 2, in correspondence of the central step component of the three shown in figure 2,

-figure 4 shows a longitudinal section view of two step components according to the embodiment of the present invention shown with reference to figures 1-3, arranged on the same row adjacent to one another, with reference in particular to the detail relating to the system for fixing to an under-structure made of steel and at the junction between the two adjacent step components ,

- figure 5a shows an axonometric view of a portion of a step component according to the embodiment of the present invention shown with reference to figures 1-4, realized according to a L-shaped structure, complete with supporting under-structure made of steel;

- figure 5b shows an axonometric view of a portion of a step component according to a second embodiment of the present invention, realised according to the Z- shaped structure, complete with supporting under . structure made of steel;

- figures 6a, 6b, 6c and 6d respectively show a side view of four step components according to further embodiments of the present invention, all comprising a L-shaped structure, and

- figures 7a, 7b, 7c and 7d respectively show a side view of four step component according to further embodiments of the present invention, all comprising a

Z-shaped structure.

Referring to the figures, a step component according to the present invention can indifferently present a L- or Z- shaped structure (cross section) , and is correspondingly indicated with the reference number

10 or 10' .

By preliminarily reference to figures l-5a, each step component 10 of the type comprising a L-shaped structure has a first portion, indicated by the reference number 11, comprising an elongated substantially rectangular surface and thickness dependent on structural needs and significantly lower than the sides of said surface, intended to be arranged in horizontal and called "tread", and a second portion, indicated with the reference number 12, arranged perpendicularly to said first portion and extending from one of two long sides of said first portion, called "riser" .

In correspondence of the free end portion of the riser 12 a first engagement portion 13 is provided and in correspondence of the free end portion of the tread 11 a second engagement portion 14 is provided, said first 13 and second 14 engagement portions being respectively deputed to engage with corresponding second 14 and first 13 engagement portions of respective step components 10 arranged above or below each step component 10 according to the present invention.

The shape of the engagement portions 13 and 14 is such as to have, proceeding from the outside towards the inside of the grandstand structure, a step 15 rising upwards, the function of which is to prevent the passage of water towards the underlying part of the grandstand. To carry out the same function, it is alternatively possible to realize the step 15 on one first engagement portion 13 of the free end portion of the riser 12, while the free end portion of the tread 11 can be made straight and flush with the lower surface of the tread 11 for reasons of simplicity of construction.

The ends of the tread 11 of each step component 10 are supported on a saddle 17 for support and coupling, possibly reinforced with a strengthening plate 16, and to said saddle 17 are fixed by means of pins 18 provided with a threaded end, passing through suitable through-holes 19 of the step component 10 and the saddle 17. The threaded end of said pins 18 protrudes below the saddle 17 and a bolt 20 is screwed on it. The saddle 17 for support and coupling rests and is welded to an underlying structure 21.

Moreover, with reference in particular to figure

2, seats 22 are shown mounted on each step component 10. Since the laminated wood is a homogeneous material and pierceable with excellent mechanical resistance, the fastening of the seats 22 must not occur at preset positions, but can be made on site, without the need for special and expensive predispositions.

Referring to Figure 4, in which two steps components 10 arranged on the same row adjacent to one another are shown in longitudinal section, it is also shown as between said step components 10 is however necessary to leave a expansion gap 23. By virtue of the characteristics of laminated wood, the expansion gap 23 is, however, much smaller than that which would be necessary to provide for corresponding structures made of steel, which makes it possible to prevent the passage of water through said expansion space 23 simply filling it with an element of sealing 24.

Again, Figures 5a and 5b bring into comparison step components according to two embodiments of the present invention, respectively with L- or Z- shaped structure (cross section) , correspondingly indicated with the reference number 10 or 10' . The step component 10', with Z-shaped structure, differs from that shown with reference to figures 1-4 for the sole reason of being provided with two portions of risers, 12' and 12" , respectively in correspondence of the two opposite long sides of the tread 11, the first extending upwards and the second downwards. In this case, a first engagement portion 13 is realized in correspondence of the free end portion of the riser 12' extending upwards and a second engagement portion 14 is made in correspondence of the free end portion of the riser 12" extending downwards, said first 13 and second 14 engagement portions being respectively deputed to engage with corresponding second 14 and first 13 engagement portions of respective step components 10' arranged above or below each step component 10' according to this second embodiment of the present invention. In this case also the free end portion of the riser 12" extending downwards can be made straight.

For the rest, the step components 10 having L- shaped structure (cross-section) and the step components 10' having Z-shaped structure (cross- section) do not have additional manufacturing differences and/or mounting.

Finally, with reference respectively to figures 6a, 6b, 6c and 6d and to figures 7a, 7b, 7c and 7d the four sections of step components more used for the construction of sports stadiums are shown by way of example, respectively in cases of L- and Z-shaped structure Z. The figures also show, by way of example not limitative of the scope of the present invention, a possible arrangement of the slats of wood within the section.

According to preferred embodiments of the invention, the step components, when intended for structures not covered and then exposed to weathering, are coated with materials of treatment to prevent discoloration of the wood due to the action of the rain or even of the sun. Such treatments may be preventive to the installation, such as the treatment of impregnation in an autoclave, or even subsequent to the installation and repeated periodically, such as the coating with appropriate paints treating.

A particularly preferred embodiment consists in the realization of an elastic film coating by spraying high temperature elastomer coating (such as polyurea) .

Finally, the step component according to the present invention may in special cases be designed made of reinforced laminated wood, or may include the use of steel bars that are inserted inside suitable longitudinal millings to reinforce the step components made of laminated wood.

The implementation of step components made of laminated wood according to the present invention allows to achieve the prest goals.

In particular, the step components made of laminated wood have a structural weight similar to that of the corresponding step components made according to the teachings of the previous application PCT/IB2011/055902 and approximately 4,5 times lower than the same step in reinforced concrete.

Indeed, if for example the weights are calculated of a structural step to be mounted on a distance of 8 meters, realized according to the teachings of the application PCT/IB2011/055902 , it appears that the development by weight resulting from plates 3mm thick on a 50cm section of riser and 80cm of tread with 10cm of thickness (and considering as weight of steel 7800 kg/m ³ ) , a weight is obtained of 561 kg (only for plates) , to which the weight developed by spacing profiles must be added, which, calculated in number of three, with a thickness of 2mm, and a C-shaped structure with a length of 10cm and feet long 5cm each, for a total length 8m again, a weight of 74,88 kg can be calculated.

Consequently, the total weight of a step component of 8,00m (module 80 x 50) is equal to 561 + 74,88 = 635kg approx.

Given that a step made of steel is moreover filled with polyurethane foam, for reasons of noise reduction and that the low density foam has a weight of 150 kg/m ³ , the step component once filled, would have a weight equal to 635 + 150 = 785kg.

If the same step was made of reinforced concrete, its weight should be around 3200kg.

The specific weight of a typical laminated wood (spruce) is 450 kg/m ³ , considered the case of a 50 x 80 x 800 step, it would have a resistant section of 0,20m ² x 8,00m equal to 1,60m ³ , or would result in a weight equal to 720kg, practically identical to that of a step component made of steel, known for its light weight, but without the limitations already mentioned.

The lower weight means lower costs of handling, assembly, storage and packaging, lower cost of the vertical and horizontal supporting structures and therefore of the foundations, which can be very simply point to plinths.

The further advantages in the use of laminated wood for the step components of grandstands of sports facilities and performance halls and/or meeting halls are many and are listed below.

Easy availability of material with low energy costs. The programming of trees cutting and rolling areas for reforestation in recent years has made it possible to create a positive balance in the use of this natural material. Moreover, the technology of laminated wood allows you to use almost all the material produced without losses due to wastes.

The technology of laminated wood, ie gluing and pressing slats of homogeneous material, according to predefined sections, allows an improvement of the elastic modulus of the material and the elimination of defects typical of solid wood (cracks, knots, deformations, material moisture sensitivity) .

The step component made of laminated wood is easily paintable (thanks to the porosity of the fibers) , with water-based paints or with epoxy resins, as opposed to a step in galvanized steel, which requires expensive primers and specific paints.

The step component made of laminated wood (as the step of reinforced concrete) has no need of non-slip treatment of the surface exposed to trampling. The porous surface of the wood is a natural anti-slip.

The step component made of laminated wood needs very low maintenance. The wood is practically eternal. In fact, the wood, if properly treated and not directly exposed to the elements, has a lifespan of hundreds of years .

Using a step component made of laminated wood, the attachment of the seat shall not be undertaken in predetermined positions. Being the laminated wood a homogeneous material with excellent mechanical resistance and puncture-proof , the fixing can also take place without programming of brackets, chemical nails, reinforcements, which are instead necessary in the case of use of steps made of steel or reinforced concrete.

Another advantage of the step component according to the present invention resides in the ease of obtaining simple geometric shapes. The laminated wood comes from the coupling of more slats of wood, whose thickness is between 30 and 40mm. Once the section is defined, the module is placed in a press, having soaked the slats of adhesives and resins. The result is a single element, homogeneous, finished and ready for use (after minor corrections of calibration and sanding performed mechanically on equipped benches) . In practice, the geometry of the section is obtained with few technical devices. Instead, in the case of the step components made of metal, the shape of the section is given by the folds obtained by press bending, by spacers and by welds. The welding produces tensions on the material and often some local warping (especially when using material thicknesses of less than 3 mm) . Using steel, the possibility of achieving to obtain a linear product, free of bumps or dents depends very much on the technical capability of the production facility, as well as on the correct handling of the elements once finished.

Moreover, as already mentioned, while the steel has little ability to withstand high temperatures, the laminated wood instead has excellent ability to withstand high temperatures. The laminated wood, in fact, exposed to high temperatures, does not reach its plastic phase as the steel, always remaining in the elastic phase. The only problem with laminated wood is the lack of resistance when exposed to direct flame. In fact, the combustion of laminated wood in case of direct exposure to the flame would cause a reduction of resistant sections and then a possible collapse of the structure. With proper precautions, however, it is possible to make even the laminated wood flame resistant (special coatings that make the surfaces of structures self passivating in case of fire) . The laminated wood is therefore the best building material as far as the ability to withstand heat is concerned.

Additional advantages of step components of the present invention are also obvious, which allows to exploit the low transmittance values of wood, which makes it a good item even for coverage in all those cases in which within the sport facility other facilities are present, such as gyms, museums, shopping centers and even schools, located under the grandstands .

In particular, properly sizing the thickness of each component step according to the present invention, it is possible to easily obtain total transmittance values lower than 0,35 W/m ² K, preferably equal to or lower than 0,32 W/m ² K (calculated according to the norm UNI EN ISO 6946) . In particular, in the case of a wood panel with the thicknesses indicated in the attached figures (10cm for the thickness of the tread and 18cm for the thickness of the riser) the value of the transmittance is significantly lower than the value of 0,32 imposed by the Italian legislation for energy efficiency of buildings.

Finally, another great advantage of the use of laminated wood for the realization of the step components according to the present invention consists in the fact that the laminated wood has a lower expansion and consequently allows to leave reduced expansion gaps between a step component and the step components adjacent to it. The lower amplitude of these expansion spaces allows the sealing of the same through the interposition of gaskets or siliconizing, which are not applicable instead in the case of steps made of steel, given the greater degrees of expansion of this material .

The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that variations and/or modifications may be made by those skilled in the art without departing from the relevant scope of protection, as defined by the appended claims.