DE2516895A1 - Monocoque low-slope trigonal domes for roofs - with mathematically exact minimal surfaces, assembled alternately above and below structure field - Google Patents

Abstract

System involving cable bracing held in equilibrium, can be combined with trigonal three-dimensional structural systems for mass production, the object being to provide simplified construction of geodetic domes or flat roofs (1) by means of trigonal bar lattice structure, in single-skinned layout and over wide spans. The dome or flat roof surface makes use of the static qualities of mathematically precise minimal surfaces (2), serving as external and internal skin, to take over all the tension forces of the trigonal three-dimensional structure coming together at the points of tetrahedrons (3) or similar. For this purpose they are assembled, with lever action, alternately on the upper and lower side of the single-skin trigonal structure field.

Description

Technical name of the invention: Process for the production of single-shell Trigonal domes with a low angle of inclination, taking advantage of the static properties approximately mathematically exact minimum areas as roof cladding. Also suitable for flat roofs.

a) Area of application: All areas of technology and architecture, in which trigonal space frame domes or flat roofs can be used. Particularly suitable for column-free roofing of large spans.

b) State of Technilc: Trigonal domes of large span and thus according to the previous state of the art the technology with trigonal space frameworks cannot be produced as a single shell, since the risk of static buckling between two trigonal fields with angles, which deviates slightly from 180 °, exists under load. Double-shell trigonal Space framework - domes (geodesic domes) require up to special lengths of rod material. The outer skin of the Jeodetic domes and also a curtain ceiling were made not yet in the statics of geodesic domes according to the state of the art integrated. (Lit .: MERO, Dr.Ing.kengeringhausen, Würzburg, and: R.Buckminster Fuller USA - book of the same name in German by Otto Maier-Verlag Ravensburg 1964 No. 60.116 -) c) Presentation of the invention: The invention is based on the union of Buckminster Fuller's "Tensegrity" system (Tensegrity = balanced by rope tension held pressure rods) with the trigonal space framework, which is superior in large-scale production Systems such as MERO, which do not differentiate the latter between tensile and compressive forces. You can also use your own registration kr. P 25 11 938.4 for a scaffolding system with knots in the shape of a hedgehog, which differentiates between tensile and compressive forces. the The unification of the systems is achieved by dag on the single-shell yeodetic Bar framework dome alternating on a Gberfeld and an Unterfeld Tetrahedron be built from bar framework, between them by three trigonal fields formed boundaries approximately mathematically exact minimal surfaces hung and be tense. These "minimal areas" act as the outer skin and as a suspended one Inner ceiling all tensile forces of the geodesic dome construction, while the Bar framework shows only compressive stress (with the exception of the dome edge). Here, the outer skin can have a corresponding inner skin in the form of minimal area fields (according to Pat. No. 24 39 597.9, own application) for example made of compression-molded aluminum sheet or deep-drawn Plexiglas surfaces.

d) Task: The task of the invention is problem-free production of geodesic domes or flat roofs by means of trigonal bar framework in single-shell Execution with large achievable span.

e) Solution: According to the invention, this problem has been solved in that a geodetic network of equilateral triangles made up of nodes and standard letters is formed in which three equilateral colliding at the corner points Triangles omitting the triangle in between with isosceles Tetrahedra of the next shorter standard rod length of the geometric series with a factor be populated. Do the same on the underside of the mesh from equilateral Triangles have the effect that all traction forces are now applied to the tips that act as levers of isosceles tetrahedron. If you now provide the space nodes with a hook-shaped approach piece, so you can use the prefabricated minimal surfaces, which have the basic shape of a spatial hexagon with 90 ° angles (not 102 °!) Attach and tighten at their corner points using snap hooks and turnbuckles. The top and bottom are only stretched so far that they do not deviate from the 90 ° angle then get a flat wing. You stretch it in such a way that there is an edge between "minimal surfaces" and the pipe construction forms a small angle, you get a single-shell Dome. If the dome is formed, there is a slight deviation from the standard angle in the junction one that can be brought under control - without having to choose special nodes, when using the hedgehog-shaped space nodes (P 25 11 938.4) rod material sticks on the tenons with a little tolerance.

The tetrahedra remain firmly fixed with every dome inclination, the rod length always remains the same (e.g. length 1 heter) The bar length of the equilateral triangles on the other hand, it decreases with increasing cupola curvature (<# 2 = less than 141.4 cm) but neglected for domes with a large diameter and therefore a small angle of inclination can be. The angle of the spatial hexagon minimum surfaces remains at every second Corner 900, but must be at the corners in between if the dome is more curved be changed. In any case, however, there will be a large number of constant parts required for the roof skin and the suspended ceiling, so that large-scale production lolxlt.

Summary: the larger the dome span and the smaller it is the angle of inclination between the fields, the more rational and unproblematic is the production of single-shell domes with integrated "minimal areas" -external- and inner skin. Constant special profiles must be used to seal the "minimal areas" are inserted.

f) broader embodiment of the invention: the principle presented is identical also for all space frame solutions derived from the trigonal basic form as applicable and should in the course of the further development of the invention on these foriles to be examined. The technical details of waterproofing and the cheapest The use of materials should be examined and fixed in the further development.

g) achievable advantages of the invention: Due to the static integration Divided into minimal areas by the roof cladding and suspended ceiling, the following result economic and technical advantages: 1.) For each field of the single-skin dome at least three bar lengths are saved, primarily in special dimensions.

2) Since all tensile forces (with the exception of the ground anchoring) from "minimal areas" a simpler space frame system can be used become. (e.g.

Pat. No. P 25 11 938.4 3) The assembly work is simplified because it is not all parts have to be screwed or welded.

4) The result is a richly structured roof shape, which extends through the fact that it is part of the statics, and thereby rod material iiil compared to the simplest double-sided solution is saved, at least partially self-financed. An outer skin, however designed, will open up any case needed.

5) It is possible for the first time, single-skin geodesic domeIl small Inclination angle and the same type of Flaclldach. This related to the shell of the space framework.

6) The geodesic domes with a low angle of inclination with "minimal surfaces" - Covering only requires one standard node and two standard bar lengths.

7) The roof elements formed from spatial "minimal surface" hexagons are ideally the same inside and outside and thus allow large-scale production. Even if every second right angle is modified, the same number of items will be produced in question.

8) The cavity formed by the double-tension ceiling can be used for laying used by installation lines and serves to isolate the dome.

h) Disadvantages of the invention: eryeben with greater dome curvature Deviations from the ideal shape of the "minimal surface" roof elements are due to angular deviation between exterior and interior cladding. There will then be at least two different ones Moldings necessary.

If the dome curvature is very small, however, it is necessary to use rainwater in each low point between three "minimal surface" roof elements through a system of drainage hoses inside. Masses of snow must in this case be defrosted with warm air in the space between the roof cladding.

i) Description of the drawings: Fig. 1 shows the plan view the dome or flat roof formed from equilateral hexagons. 1) The double bordered area denotes the position of a "minimal" area. 2) Attached to the outside right-angled tetrahedron. 3) The dashed lines show those placed on the inside right-angled tetrahedron, Fig. 2 shows a modification of the same application in diamond-shaped Layout. 1) shows the position of a "minimal area" unit. 2) shows the location of the TIal octahedron attached to the outside.

3) shows the position (dotted line) of the semi-octahedra placed on the inside.

3 shows FIG. 1 in section. 1) shows the one drawn as a flat roof Area which in 2) can seamlessly transition into different dome curvatures. this is also made clear by the vertex angles shown. The previously feared Buckling of single-shell bar framework constructions is definitely avoided.

FIG. 4 shows an enlarged representation of FIG. 3 without any scale. 1) shows the reinforced "minimal area" border, 2) the "minimal area" skin, 3) shows the hedgehog-shaped knot with hook attachment, 5) shows the cover between two fields, 4) shows the turnbuckles, 6) shows the slight difference between "Minimal surface" element of 90 ° and the bar framework with a slight deviation of the Angle of 180 °.

Claims (3)

# 3a claims: 1. is to be protected as patentable in the main claim: Process for the production of single-shell trigonal space frame domes with low Angle of inclination and large span and similar flat roofs, characterized in that that using the static properties approximately mathematically more exact Minimal areas, the dome or flat roof surface designed as an outer and inner skin all tensile forces of the trigonal space framework take over those at the tips collected by tetrahedra (or octahedra, etc.), provided that they have a leverage effect alternately on the top and bottom of the single-shell trigonal space framework field to be assembled. 2.) in the sub-claim should be placed under protection that the same Procedure also for other variations of the trigonal than those shown in the drawing The space frame system is rarely used. Likewise, should be placed under protection in subclaims Execution with only one roof skin without a sub-ceiling, be it that the sub-skin is through Ropes are replaced, or in the case of an approximated icosahedron, the buckling moment is not given. 3.) In the secondary claim, accessories to be explained in more detail, such as cover profiles, in particular the hook-shaped or ring-shaped additional part for the various Rod framework enotes Fig. 4, 3) are placed under protection.