NL2021269B1 - Structural element - Google Patents

Abstract

EXTRACT The present invention relates to a structural element that is at least partially made of wood, such as a pole or board, which element can be placed in the ground or in water and then partially protrudes above the ground or above the water. The aforementioned element comprises at least two parts of wood which are in principle inextricably connected to each other.

Description

12 2021269 © B1 PATENT (2?) Application number: 2021269 (22) Application submitted: July 9, 2018 (51) Int. Cl .:

E02B 3/12 (2018.01) E02D 5/26 (2018.01) E02D 5/48 (2018.01) E02D 17/08 (2018.01) E02B 3/04 (2019.01) E02B5 / 02 (2019.01) E04H 12/04 (2019.01) E04H 12 / 22 (2019.01) (30) Priority:

(73) Patent holder (s):

Van Swaay Schijndel B.V. te SCHIJNDEL (77) Application registered:

January 2020 (43) Request published:

(72) Inventor (s):

Inventor refrains from being registered.

(74) Agent:

ir. A. Blokland et al. in Eindhoven

47) Patent granted:

January 2020 (45) Patent issued:

January 2020

54) Structural element

57) The present invention relates to a structural element that is at least partially made of wood, such as a post or plank, which element can be placed in the ground or in water and then partially protrudes above the ground or above the water . The aforementioned element comprises at least two parts of wood, which are in principle inseparable from each other.

B1 2021269

This patent has been granted regardless of the attached result of the research into the state of the art and written opinion. The patent differs from the documents originally submitted. All submitted documents can be viewed at the Netherlands Patent Office.

Title: Structural element

The present invention relates to a structural element made from wood, such as a post or plank, which element can be placed in the ground or in water and then partially protrudes above the ground or above the water. The aforementioned element comprises at least two parts of wood, which are in principle inseparable from each other.

Such an element is known, for example, from NL 1014570 in the name of the present applicant. The structural element known therefrom is made of wood and consists of at least two parts of timber, viewed in height, of durability, which parts are in principle inextricably linked to each other. The part that has been placed in water is not preserved with chemical agents to prevent the preservative from being leached out of the part and getting into the water. The types of wood to be used are, according to this Dutch patent, whether or not preserved European softwood or hardwood. Hardwood can be tropical or European wood from trees grown in Europe.

A similar structural element is also known from Dutch patent 1006984. The structural element known therefrom is intended to manufacture a baffle for protection of banks, which baffle consists of shelves which are connected at regular distances to connecting elements, some shelves being made of wood and another part of the boards is made of plastic. A disadvantageous aspect of the partitions thus produced is that two fundamentally different materials are incorporated into an element, namely wood and plastic, which materials have different mechanical properties, such as, for example, flexural strength, which can lead to undesirable situations, for example fracture.

A similar structural element is also known from Dutch patent 1014970. The structural element known therefrom is intended to protrude above ground level with a first part and to be used at least partially below ground level with a second part, the first part comprising wood comprising a first durability and the second part comprises a material with a second durability greater than the first durability of the first part. The second part is made from a plastic, the plastic being extracted from a recycling process.

A similar structural element is also known from Dutch patent NL1031945. The hydraulic construction element known therefrom comprises a first part and a second part which are tightly connected to each other by means of a connection with an adhesive comprising a melamine, wherein the second part is intended to be applied at least partially under water, and wherein at least the second part of wood.

The German patent specification DE 808280 relates to a wooden mast, in particular for electrical cables, in which the lower part of the mast, which must stand in the ground and come into contact with the ground, is impregnated and cured with synthetic resin. To that end, the part of the mast to be hardened is first made air and anhydrous by evacuation, after which a resin solution is then introduced into the pores of the wood, the mast piece being subjected to a heat treatment under pressure to cure the resin.

The US publication US 2009/0077919 relates to a floor element that is used to form a warp-resistant, hardwood floor part on concrete, comprising a top layer of hardwood and a number of non-hardwood layers located below that are using an adhesive layer. connected.

United States publication US 2015/0190972 relates to a method for reinforcing a structure using a resin-impregnated heatable reinforcement sheet, the method comprising: a step of wrapping, laying or attaching a resin-impregnated reinforcement sheet (HRW) ) on a surface of the structure or on a surface of a spacer sleeve that surrounds the structure, the reinforcement sheet being configured to be actively heated and the resin configured to be at least partially cured when the impregnated reinforcement sheet is heated, which The method further comprises a step of heating the reinforcement sheet to heat the resin and at least partially cure the resin.

The US publication US 2007/0193179 relates to a floor surface of a vehicle, the floor of the vehicle comprising: a number of wooden boards extending longitudinally to a length substantially equal to the longitudinal of the length of the floor, the floor is formed from a number of planks arranged side by side, each plank being formed from at least two rows of a plurality of planks, each plank being formed from a number of segments connected to one another by shaped coupling sections and side by side along an adhesive line wherein each of the at least two rows is longitudinally offset with respect to an adjacent row, such that a line of glue is shifted with respect to a line of glue from an adjacent row, the wooden boards being hardwood boards.

German Offenlegungsschrift 44 41 672 relates to a wood preservative containing a dimethylalkylamine, an aliphatic C8 -C20 dicarboxylic acid and a triazole compound. To protect the wood against fungi, the wood is treated with an impregnating solution containing the aforementioned wood preservative and water.

In addition, structural elements of wood that are placed in the ground or in the water are also known from the German publication DE 41 31 941, the US patent US 5,674,338 and the UK publication 167,948.

Wood is generally divided into two main groups, deciduous hardwood (from deciduous trees (belonging to the flowering plants or angiosperms)), also known as hardwood, and coniferous wood (from coniferous trees (belonging to the nudiforms or gymnosperms)), whereby it can be noted that, in general, softwood is softer than hardwood. The following wood species belong to the main group of softwoods: pine (Pinus silvestris), larch or larches (Larix decidua and spp.), Douglas (Pseudotsuga menziesii), spruce (P / cea), hemlock (Tsuga spp.), Parana pine (Araucaria angustifolia), pin des landes (Pinus pinaster), pitch pine (Pinus spp.).

A disadvantageous aspect of the commercially available structural elements is that when two different main groups of wood are used in the same structural element, for example a combination of (tropical) hardwood and softwood, two materials with considerably different mechanical properties are intimately connected to each other . Due to these different mechanical properties, stress concentrations can occur around this connection when this connection is loaded, which in exceptional cases can lead to breakage. This adverse effect can occur, for example, if there is an overload. A disadvantage of the structural elements thus commercially available is the vulnerability in the event of overload. As a result, the chance of breakage increases significantly, which results in a considerable restriction with regard to use and life. Because the dimensioning of wooden sheet pile structures and embankments is not always based on a thorough soil investigation and a good calculation and because even after soil investigation there are always uncertainties, there is a chance of failure. It is thus desirable to lower the aforementioned stress concentrations, thereby reducing the chance of failure, resulting in an increase in the enjoyment of use, the service life and the application possibilities of structural elements.

When using tropical hardwood and softwood in the same structural element, problems can thus arise that are related to the bending moment in the wood. If a considerable force is exerted on such a structural element, the element (usually) breaks just below the joining area of both wood groups.

Sheet piles and piles, in which pine and tropical hardwood are combined, are an accepted alternative to (wooden) sheet piles and piles that are made entirely in one type of wood. Because the mechanical properties of the types of wood from which such sheet piles and piles are composed are very different, effects can occur during installation and at the use stage that were not foreseen by the constructor and the contractor. The reason for this is that constructors use calculation programs that do not or insufficiently take into account the different mechanical properties of the component parts. During the placing of the sheet pile the contractor, who is used to handling homogeneous planks or posts, also has to deal with the different mechanical properties. This results in a greater chance of failure than desired.

An object of the present invention is thus to provide a structural element that lacks the aforementioned disadvantage, or an element in which the aforementioned disadvantage is reduced to a considerable extent.

The structural element according to the present invention thus supervises a structural element which is at least partially made from wood, such as a pole or plank, which element can be placed in the ground or in water and then partially protrudes above the ground or above the water, said element comprising at least two parts of wood, in principle inseparably connected to each other, characterized in that said parts are made of the same main group of wood, one part being an untreated type of wood of said main group of wood and the the other part is a treated type of wood from the aforementioned main group of wood.

One or more objectives are met by applying such a constructive element. In particular, the use of two types of wood from the same main group will increase the flexibility of the final structural element. The aforementioned flexibility is due, among other things, to a combination of mechanical properties, in particular a combination of, among other things, flexural strength and E-modulus, which combination of mechanical properties ensures a considerably reduced risk of breakage. The present inventors have found that a structure obtained with such an element, for example a pile or sheet pile, has a higher resistance to breakage because the strength properties are more homogeneous than those obtained with the commercially available structural elements.

In an embodiment of the present structural element, the aforementioned parts are thus manufactured from the same main group of wood. Such a choice of material makes it possible to use parts with comparable mechanical properties in one and the same structural element, thereby improving the flexural strength properties relative to a structural element in which different main groups of wood, for example softwood and hardwood, each with their own, strongly different E-modulus and / or permissible flexural strength can be used. In the present structural element, the aforementioned parts are manufactured from the same main group of wood, which also includes recycled materials.

As a suitable type of wood to be used in the present structural element as a treated wood type, the group of chemically modified wood is mentioned, in which in particular softwood can be mentioned Accoya (brand), from Pinus Radiata.

In the present structural element, one part is made from an untreated wood type and the other part is made from a treated wood type, the same main group being made of wood.

A modified wood is mentioned as an example of a treated wood. It should be noted here that modification is a substantially different method than sustainability. Modifying is changing the properties of the material by adding one or more other substances where the purpose of the change is to improve the properties, for example, more resistant to influences of the weather and the environment. Modified wood does not obtain its good properties through toxicity as with preservation with copper-containing agents, but has become highly inert to biological attack due to the change. Two methods of modifying wood can be mentioned. A chemical modification can thus be mentioned whereby the wood structure is adjusted. Thus, for example, in acetylated wood, the hydroxyl groups have been replaced by acetyl groups. And with thermal modification, the wood structure is often adjusted under pressure.

In one embodiment of the present structural element, none of the parts is preserved with chemical wood preservatives. Chemical preservation means that the wood is made resistant to the activity of rotting fungi, bacteria and insects. When preserving with biocides, a 'shell' is made of preserved wood without the wood having to be thoroughly impregnated. The impregnated shell ensures that insects cannot penetrate and fungi do not find a breeding ground for their growth. The thickness of the impregnated zone and the amount of active substances differ per type of wood and per application. It can thus be stated that fungi and insects are kept at a distance and killed by the preservative when preserving the wood (by eating fungi and insects). When modifying, the wood in its cell structure and molecular structure is modified in such a way that fungi and insects no longer recognize the wood as wood.

In an embodiment of the present structural element, the aforementioned two parts of wood are, in principle, inseparably connected to each other using a finger joint. The present inventors have thus found that two parts of the same main group of wood, which are joined together by finger welding, with only one part being modified with an (environmentally-friendly) agent, provide unique durability and greatly improved results to the end product. The combined or composite product of, for example, modified softwood has an expected lifespan of more than 40 years. In the combination with tropical hardwood that is known according to the state of the art, durability class 1 applies, a lifespan of approximately 25 years. According to the present invention, the service life is thus almost doubled (40 years compared to 25 years). Because of this extension, the soil will also be stirred less often and this has a great ecological advantage. Examples of structural elements according to the present invention may be mentioned: combinations of, for example, pine and spruce, pine and larch, larch and spruce, or other combinations of wood from the same main group of wood, but also only the use of one type of wood from the same main group of wood, for example only pine or only spruce.

Research has shown that selection criteria are required for the modified wood to match the mechanical properties of the chemically modified wood and the untreated wood as much as possible.

According to the present inventors, the requirements that are desirable for sorting the modified wood will thus lead to sheet piles and piles with strength class between C18 and C24. Thus, in certain embodiments, it is preferable that the chemically modified wood meets one or more of the following conditions:

The maximum allowed brush size is 50 mm. This brush is continuous.

Brushes must be at least 150 mm from the end that the finger joint will receive (3x maximum brush size). No minimum distance is required on the front side.

Brushes that are not continuous (truncated Brushes) are not set to a maximum brush size.

It is desirable that all brushes are stuck. It is also desirable that there are no brushes in the finger joint area. From a mechanical point of view, it is preferable that continuous open defects (ingrown bark, etc.) and resin passages are missing (from side to side).

In order to prevent the construction of a structural element having insufficient mechanical properties, it is desirable that in the aforementioned two parts of wood the maximum permitted brush size is at most 50 mm, in particular continuous or continuous type brushes.

In an embodiment of the present structural element, it is desirable that brushes be located at a minimum distance of 150 mm from said area in the area where one part of wood is connected to the other part of wood.

In an embodiment of the present structural element, it is desirable that at most two brushes with a diameter of at most 30 mm are aligned, perpendicular to the fiber direction of the type of wood used.

The present inventors have thus found that by joining two types of wood from the same main group of wood, the collapse limit of such a structural element becomes higher than with a structural element that is composed of two types of wood from a different main group of wood. The use of a structural element according to the present invention also reduces the chance of failure during setting and the period of use. Another advantage is that the structural element according to the present invention is lighter in weight, so that contractors with less heavy equipment can place the product and it becomes easier to place the sheet pile / piles. With regard to production, it can be noted that after finger welding, the structural element according to the present invention is less vulnerable on the production belt because both parts of the structural element have a comparable weight. In particular, it further holds that by adding selection criteria for the chemically modified wood, the mechanical properties of the chemically modified wood and the untreated (coniferous) wood are as consistent as possible with each other.

The present invention thus supervises a sheet pile wall made from one or more structural elements as described above,

The present invention furthermore supervises a pole made from one or more structural elements as described above.

Figure 1 supervises a structural element according to the present invention, arranged in a basic structure.

Figure 2 supervises a structural element according to the present invention arranged in water.

Example

In the enclosed figure 1 two posts 1, 2 are shown and a board 3 arranged in a base construction 10 to level 20. As shown in the figure, the structural element 1 has a round shape and the structural element 2 has a square shape. The posts 1 and 2 and board 3 each consist of two parts, viz. 4, 5 respectively 6, 7 and 8,9 wherein parts 4, 6 and 8 are each manufactured from a treated type of wood, namely modified, and the other parts 5, 7 and 9 comprise an untreated type of wood, both types of wood belonging to the same main group of wood . The parts 4 and 5 are preferably connected to each other via a finger joint 11. The same type of connection applies to parts 6 and 7, via a finger joint bond 12, and parts 8 and 9, via a finger joint bond 13. In the application in a ground construction it is necessary that the finger joint bond be above the ground, as shown in Figure 1.

In the enclosed figure 2, in which there is a positioning in an aqueous environment, for example a channel, two posts 1, 2 and a board 3 are arranged in an aqueous environment up to level 25. Posts 1, 2 and board 3 are in fixed substrate 30, which substrate 30 is located under the aqueous environment. As shown in Figure 2, the structural element 1 has a round shape, the structural element 2 has a square shape and the structural element 3 has a rectangular shape. The posts 1 and 2 and board 3 each consist of two parts, viz. 14, 22 respectively 16, 23 and 18, 24 wherein the parts 22, 23 and 24 are each made from a treated wood group, in particular by modification, and the other parts 14, 16 and 18 comprise an untreated wood group, both wood groups being the same. The parts 22 and 14 are preferably connected to each other via a finger joint 19. The same type of connection applies to parts 16 and 23, via a finger joint binding 26 and parts 18 and 24, via a finger joint binding 21. In the application in an aqueous environment it is necessary that the finger joint binding 19, 26, 21 is always below the water level, as shown in figure 2. In figure 2, part 14 is composed of untreated pine and part 22 of modified pine. In Figure 2, part 16 is composed, for example, of untreated fires and part 23 of modified Radiata pine. In Figure 2, part 18 is composed, for example, of untreated fires and part 24 of modified larch.

Claims (5)

CONCLUSIONS A structural element, at least partially made from wood, such as a post or plank, which element can be placed in the ground or in water and then partially protrudes above the ground or above the water, said element being at least two, comprises in principle inseparably joined parts of wood, characterized in that said parts are made of the same main group of wood, one part being an untreated wood of said main group of wood and the other part a treated wood of said main group of wood is. Structural element according to claim 1, characterized in that said treated wood type can be considered as a modified wood type. Structural element according to claim 2, characterized in that said modified wood type is a chemically modified wood type. Structural element according to one or more of claims 1-3, characterized in that said main group of wood comprises the group of softwood. Structural element according to one or more of claims 1-4, characterized in that none of the components is chemically preserved. Structural element according to one or more of the preceding claims, characterized in that said two parts from the same main group of wood are in principle inseparably connected to each other using a finger joint. Structural element as claimed in one or more of the foregoing claims, characterized in that in the aforementioned two parts from the same main group of wood the maximum permitted brush size is at most 50 mm, in particular brushes of the continuous or continuous type. Structural element according to one or more of the preceding claims, characterized in that brushes at a minimum distance of 150 mm from the area where one part of the same main group of wood is connected to the other part of the same main group of wood the aforementioned area. Structural element according to one or more of the preceding claims, characterized in that at most two brushes with a diameter of at most 30 mm may be aligned, perpendicular to the fiber direction of the main wood group used. Sheet pile made of one or more structural elements as defined in one or more of the preceding claims 1-9. 11. Pole made from one or more structural elements as defined in one or more of the preceding claims 1-9.