Patent Application
20060207216
The invention relates to an element of construction according to the preamble of claim 1.
In building construction particularly, board-shaped elements of construction are employed as part of the façade scaffolding. A plurality of application classes, defined by the size (width of the board), working load and intended purpose among other factors, are distinguished. Because a façade scaffolding is a temporary structure, these scaffoldings are usually of modular construction; that is, virtually any scaffolding design can be put up with a small number of uniformly constructed elements (ledgers, bearers, and boards).
The board-shaped elements of construction ordinarily have a length of 250 cm and a width between 60 cm and 90 cm. As a rule, they are used for all application classes. They experience loading primarily in flexure but, in addition, must also be able to handle individual concentrated loading cases.
Elements of wood, a wood-aluminum composite, aluminum, or steel are conventionally used for the boards. All these materials, however, have specific disadvantages.
Wood elements, for example, absorb water, which can lead to externally invisible rotting, in particular of the wood core, and unforeseeable fracturing of the board element. In order to avoid this sudden failure due to water absorption, such wooden boards must be inspected periodically. The lifetime or service life of such board elements is thus greatly limited. Water absorption further leads to a gain in the weight of these board elements, which on the one hand has a disadvantageous impact on the handling of the elements when scaffoldings are being erected or dismantled at the construction site and on the other hand increases the dead weight of the scaffolding, leading to a reduction in the working load.
In the case of composite or hybrid wood-aluminum boards, while the dead weight is reduced in comparison with the plain wood board, the same disadvantages in terms of water absorption are present as in the previous case. Along with the danger of failure due to water absorption, here there is a further possibility of failure of the welds in the aluminum frames.
Plain aluminum boards in comparison with composite or hybrid boards do not exhibit any major differences in terms of weight but are not susceptible to water absorption. Such boards, however, have very poor fatigue properties with respect to the danger of failure of the welds, which again means that the lifetime is limited. Boards currently available on the market also have a low resistance to skidding, which has a disadvantageous impact on safety.
All conventional boards have a high specific weight, which has a disadvantageous impact particularly on handling, that is, assembly, dismantling, transport and storage.
In order to address these disadvantages, trials with alternative materials have also been carried out. In particular, boards have been fabricated from fiber-reinforced plastic, which led to lower weights and better environmental stability in comparison with conventional boards. As a rule, however, plastics exhibit an unfavorable modulus of elasticity, so that either the required properties could not be attained or else very thick boards resulted.
It was a goal of the present invention to furnish such a board-shaped element of construction that would, at the lowest possible weight, be able to accommodate the required flexural loads.
According to the invention, this goal is achieved with an element of construction having the features of claim 1.
Further preferred embodiments arise from the features of claims 2 to 12.
By fashioning the element with a flat compression chord and lateral tension chords, it is possible to attain a high flexural strength with a slight wall thickness, which advantageously leads in the end to low weight of the element along with small dimensions. Fashioning the element with transverse ribs arranged beneath the base plate permits the construction of a base plate of relatively slight thickness.
In a preferred embodiment, dimples are fashioned in the surface, planar transverse regions being left to reinforce the transverse ribs arranged beneath the base plate, the dimples permitting the construction of a base plate of relatively slight thickness. Here the use of plastic, preferably fiber-reinforced plastic, results in a stiffness satisfying the requirements.
The dimples are advantageously fashioned only deep enough that the stiffening action is sufficient but no disadvantages arise in terms of the serviceability of the element of construction. This means in particular the suitability of the element of construction as a surface for walking on, which is not to be impaired by excessively deep or upwardly protruding elements.
Through the use of carbon-fiber-reinforced plastic elements such as for example carbon-fiber-reinforced plastic strips, the tensile loading of individual regions of the element of construction can be increased in a controlled way without any substantial effect on—that is, gain in—the dimensions or weight. These reinforcements are preferably affixed in the region of the maximal tensile loads, that is, on the undersides of the transverse ribs and the lower regions of the two external flanges.
By virtue of the preferred fashioning of the connecting elements as downwardly open profiled members having a rounded cross section, the elements of construction are easily connected to one another as well as for example to cross-rails of scaffolding structures. Of course, any other connecting elements can also be affixed on the transverse sides of the element of construction so as to correspond to the intended use and fashioning of the corresponding connectors of, for example, the scaffolding structure. Preferably in the form of elements fashioned in the shape of hooks, which are connected for example to the flanges of the element of construction and extend therefrom in the longitudinal direction.
In what follows, exemplary embodiments of the invention are explained in greater detail with reference to the drawings, in which:
From base plate 1, flange surfaces 4 extend downwardly along both longitudinal sides. Flange surfaces 4 are advantageously rounded at the ends, as can be inferred in particular from
These profiled members 6 can now be suspended or laid, for example, on cross-rails of scaffolding structures (not depicted). These profiled members 6 belonging to elements of construction succeeding one another in the longitudinal direction can be arranged engagingly one over another, and in this way for example connected in common to a cross-rail.
On the underside of transverse regions 3, transverse ribs 7 extending over the entire width of base plate 1 are now fashioned. The ends of these transverse ribs 7 make a transition directly into flange surfaces 4 or are connected to these. Buckling of flange surfaces 4 under loading of base plate 1 is avoided in this way.
By virtue of this embodiment of the element of construction, a stiff board-shaped element can be created from relatively thin material. Base plate I with dimples 2 serves as the compression chord and the two flange surfaces 4 as tension chord of the element.
Such an element of construction can advantageously be fabricated from plastic, which leads on the one hand to an advantageous resistance to weathering and on the other hand exhibits high stiffness together with light weight on account of the shaping according to the invention. In this way, such elements of construction are particularly good to handle and are suitable in particular for use as weight-bearing boards for scaffoldings.
In
Transverse rib 7 advantageously has a porous core, for example of honeycomb construction. This core can be surrounded by a cover layer 9, preferably made of plastic. This layer can be fashioned as a single or multiple layer. Additionally, a reinforcement 10 of carbon-fiber-reinforced plastic can be attached, advantageously to the underside of transverse rib 7 as depicted in
Transverse rib 7 advantageously has a trapezoidal cross section, which on the one hand guarantees optimal transmission and accommodation of forces and on the other hand is simple and thus favorable in terms of fabrication.
Further, flange surfaces 4 can also have reinforcements of carbon-fiber-reinforced plastic, in particular in the lower region, in order to enhance the stiffness and ability to handle tensile loading. In this way, the maximal permissible loading and working load of the element of construction can be set in accordance with requirements.
Also depicted, in
On page 8, lines 25-26, the original reads Knick—resp. Beulsteifigkeit, where Knicksteifigkeit and Beulsteifigkeit are synonyms meaning “buckling stiffness.”—Translator.
Naturally, the element of construction can also be fashioned without dimples 2, with a substantially planar surface 1. The surface can now preferably be provided with a skid-resistant coating, which substantially enhances the safety of the element of construction specifically in scaffolding construction.
For example, a longitudinal section through such an element of construction is depicted in
The combination of longitudinal and transverse elements according to the invention results in a simple, flexurally stiff, and lightweight element of construction that can be fabricated from fiber-reinforced plastic. These materials are easy to process and exhibit especially good weathering and corrosion properties together with high stability and light weight. When used as deck elements for façade scaffoldings, such elements of construction are distinguished by their advantageous properties with respect to storability and transport, as well as by rapidity in handling. Further application fields therefore lie in the construction of exhibits and stages and in the façade aspect of building construction.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CH03/00092 | 2/6/2003 | WO | 4/13/2006 |
