EP0070532B1 - Sound insulating wall building system for industrial buildings and cassette section for the system - Google Patents

Abstract

1. Sound-absorbing wall construction system for industrial buildings to be constructed as steel or reinforced concrete skeleton structures, such as power plant buildings, featuring long, thinwalled cassette sections (2) to accomodate insulating material, which can be connected with each other to form a space-enclosing wall as well as with the columns (1) of the steel or reinforced concrete skeleton, and a bottom boom (3) that can be arranged horizontally and parallely to the columns (1) as well as angled webs (4), (5) on the two long sides of the bottom boom (3) and at least one top boom (6) angled off from one of the webs (4) which serves to fix a facing (8) covering the individual cassette sections (2) on the outside, characterized in that a bent-off edge (7) has been provided on the outer long edge of the top boom (6) of one of the webs (4) aiming in the direction of the bottom boom (3) and that the other web (5) is designed without a top boom and shorter than the first web (4).

Description

The invention relates to a sound-absorbing wall construction system for industrial buildings to be erected in steel or reinforced concrete skeleton construction, such as power plant buildings, according to the preamble of claim 1, and to a cassette profile particularly suitable for this.

Wall construction systems in skeleton construction are used in particular for commercial buildings such as power plant buildings and towers. A construction method that has proven itself in practice is, for example, to provide bars made of structural steel that are spaced apart from each other, on which spacers, for example in the form of welding bolts, are used to support outer cladding made of trapezoidal sheet metal and an inner insulation layer made of mineral fiber boards or asbestos-cement boards, for example.

In a generic design, which has already been used in practice, the horizontal bars of the skeleton can be omitted in that essentially C-shaped panels or rectangular cassettes are attached directly to the upright supports. The attachment to the supports is carried out via a lower flange, which corresponds to the central part of the C-shape, while the two legs of the C-shape project outwards from the supports as webs. Sound-absorbing material, for example in the form of mineral fiber boards, can be used in the C-shape. On the outer sides of the webs, upper webs which are angled in the same direction and are parallel to the lower web are formed, which serve for stiffening and in particular form a fastening surface for the clothing to be fastened to the outside of the top webs. The free ends of the top chords are either flat or provided with a small edge bead in the manner customary in sheet metal processing in order to optically break the free edge and to avoid corrugations in the course of production.

Such a construction not only has the advantage that horizontal bars made of structural steel are saved, but also ensures that the interior of the building is closed quickly to the outside. As a result, the building is closed off by the cassettes, particularly in boiler construction, even before the insulating material is introduced into the cassettes and the clothing is fastened, so that it is no longer necessary to hang tarpaulins to protect welding work.

For this, however, it is necessary that the inner shell of the wall formed from the cassette profile profiles can withstand the static requirements of wind without cladding and the introduction of insulation material, which requires not insignificant static strength. This is also achieved with rolled cassette profiles of low sheet steel thickness of, for example, 0.75 mm with suitably small dimensions in that the adjacent webs and top chords of stacked cassette profiles abut one another and thus form a horizontal rail of increased strength with double wall thickness and mutual support, which to a certain extent corresponding horizontal bar made of profile steel replaced.

However, this planar arrangement of adjacent webs and top chords leads to other disadvantages. The fitting accuracy of the cassette profiles is too low to ensure an exact parallel position and flat mutual contact with respect to the neighboring top chords that project freely from the webs. Since the clothing in the form of trapezoidal profiles is usually fastened to the top chords by self-tapping facade screws, their anchoring is undefined and subject to randomness; This is all the more so because the upper chord located below frequently deflects elastically during predrilling and then springs back so that the screw holes are no longer exactly aligned. Particularly when using thin sheet metal thicknesses for the cassette profiles in such a way that only the sum of the wall thicknesses on the top chords gives the meat required for a perfect anchoring of the facade screws, the prescribed strength of the anchoring of the facade screws and thus the clothing can be undershot.

This risk of loosening the fastening of the clothing to the upper belts is further increased by the fact that the clothing in the form of trapezoidal profile fields extends over a plurality of superimposed cassette profiles and thus upper belts and considerable forces are introduced into the fastenings by thermal expansion and heat shrinkage. On the other hand, since the web area of the adjacent cassette profiles is well stiffened due to the double-layered structure and mutual support and only yields slightly in the transverse direction to the length of the web, these loads have to be almost completely absorbed by the facade screws, which puts additional strain on them and, in particular, their seat in the top chords.

The rigid design of the web area due to double layers and mutual support also leads to a better acoustic coupling between the inner shell formed by the bottoms or lower straps of the cassette profiles and the outer shell formed by the cladding of the wall construction system. From a sound insulation point of view, the aim should be to decouple the inner shell from the outer shell as much as possible and to limit the structurally and structurally necessary connections between the shells to as few places as possible, as well as to make these points as soft and elastic as possible in order to achieve the desired decoupling and To minimize structure-borne noise transmission. Both Previously used cassette profiles of comparatively low sheet thickness, however, the height of the lower chords is limited for structural reasons, and a connection between the inner shell and the outer shell which is particularly stiffened by the double-layered structure and mutual support of the webs takes place on the upper chords which are thus located at comparatively short distances. Viewed schematically, this results in a particularly rigid connection between the inner shell and the outer shell with a correspondingly good acoustic coupling and high structure-borne noise transmission at a large number of points.

In contrast, the invention has for its object to provide a wall construction system of the type outlined in the preamble of claim 1, which results in improved sound insulation with increased static strength.

This object is achieved by the characterizing features of claim 1.

Thereafter, only one of the webs of the cassette profile is provided with an upper belt, while the other web is shortened without an upper belt. The consequence of this is that the shortened web has only reduced strength, which decreases sharply towards its edge region; Because with thin sheet metal profiles, the »break« occurs through dents and only carries the material in the vicinity of bends or bends. For the shortened web, this means that forces are only absorbed in the corner area between the web base and the lower flange, that is, the material there bears, while the outer web edge no longer results in any significant stiffening effect. In the contact area of the web with the top flange of one cassette profile and the shortened web of the adjacent cassette profile, stiffening and mutual support therefore only take place in the region of the adjacent bottom chords, that is to say the inner shell of the wall construction system, while at a distance therefrom only the web with the top flange has stiffening effect. while the shortened bridge simply follows deforming movements without any significant resistance. This is not the case without shortening one of the webs, i.e. when two webs are created, each with an upper chord, since the corner area between the webs and the upper chords then results in a stiffening angle in both cases and thus essentially both webs over their entire length, but in any case Support and stiffen equally in the area of their two ends.

By shortening the one web it is thus achieved that the connection between the inner shell formed by the lower straps and the outer shell formed by the clothing becomes elastically softer and more flexible. This results in improved acoustic decoupling and less transmission of structure-borne noise between the inner shell and the outer shell. Furthermore, the web area becomes more flexible in the vertical direction of the wall and can elastically deflect in the event of thermal expansion of the clothing, as a result of which the load on the facade screws caused by such movements is correspondingly reduced.

The fact that on the outer longitudinal edge of the remaining top flange of the not shortened web there is a bevel pointing in the direction of the bottom flange, on the other hand results in an improved stiffening of the remaining top flange. Surprisingly, it can be seen that this stiffening not only compensates for the shortening of the other web and the absence of the second upper flange, but also results in a sudden increase in the static strength. With the same use of material, it has been shown that the fold at the outer edge of the remaining one upper chord compared to a version without such a fold, i.e. with a flat or only beaded edge, increases the strength, i.e. the load-bearing capacity of the cassette profile against bending moments from wind loads, by around Results in 200%. This surprisingly strong increase in strength, as detailed investigations have shown, is probably due to the interaction between the stiffening angle between the upper chord and the web on the one hand and the further stiffening angle created by the fold on the outer edge of the upper chord on the other hand; This interaction takes place in the sense that the additional bracing angle on the outer edge of the upper chord carries more material in the middle part of the upper chord, while with only one bracing angle between the upper chord and the web, the material of the upper chord does not contribute to the bracing even at a short distance from this bracing angle there is more. The load-bearing width of the top flange is thus considerably increased by the fold.

Overall, the strength or load-bearing capacity of the one remaining top chord with the bevel edge is greater than the strength of two abutting upper chords without a bevel, so that the load-bearing capacity of the remaining one upper chord with a bevel in the wall construction system according to the invention is greater than the load capacity of the two top chords in the generic wall construction system .

Overall, a comparative analysis of the generic wall construction system with the wall construction system according to the invention thus shows that in the wall construction system according to the invention the web area is statically weakened and the acoustic decoupling is thereby improved and the web area can yield elastically during sliding movements of the clothing made of trapezoidal profile sheet metal, while on the other hand the strength in the area of the remaining top flange is increased by leaps and bounds due to the technically simple measure of the additional bending against deflection, so that overall, despite the weakening of the web area, the overall load-bearing capacity of the cassette profile is higher. The Schwä chung in the web area in the wall construction system according to the invention thus only comes into play in the case of vertical forces acting on the upper chords, for example due to the weight of the clothing, since the stiffened remaining upper chord can be moved parallel to the lower chord more easily. This resultant weakening, which does not apply to wind forces acting in the horizontal direction, can be taken into account in a simple manner by locally installing additional stiffeners on the upright supports in the connection area of the cassettes, which reinforce the horizontal position of the load-bearing in the installation secure, unabridged web. These stiffening internals are limited to the connection area of the supports and therefore do not appear to be noticeably disadvantageous overall, especially since the distance between the upright supports can be increased due to the increased load-bearing capacity of the cassette profiles in the wall construction system according to the invention. In the case of a planned building, for example, there is a mutual distance between the upright supports of 8 m.

The subclaims 2 to 9 contain advantageous developments of the invention. A cassette profile according to claim 10 also realizes the principle according to the invention before installation in a wall construction system according to the invention and is independently tradable.

• Fig. 1 in einer perspektivischen Darstellung einen vertikal geschnittenen Ausschnitt aus einem erfindungsgemäßen Wandbausystem, wobei ein Kassettenprofil vor der Einbringung des Wärmedämmaterials dargestellt ist und die Bekleidung insgesamt noch fehlt,
• Fig. 2 in einer Darstellung entsprechend Kreis 11 in Fig. 1 eine abgewandelte Ausführungsform der Erfindung,
• Fig. 3 in einem Vertikalschnitt eine Darstellung des Wandbausystems gemäß Fig. 1 mit angebrachter Bekleidung, und
• Fig. 4 schematisch den Querschnitt des beim Wandbausystem gemäß den Fig. 1 und 3 verwendeten speziellen Kassettenprofils zur Erläuterung der Bemessung im vorliegenden Beispielsfalle.

Further details, features and advantages of the invention result from the following description of exemplary embodiments with reference to the drawing. It shows

• 1 is a perspective view of a vertically sectioned section of a wall construction system according to the invention, a cassette profile being shown before the thermal insulation material is introduced and the clothing as a whole is still missing,
• 2 in a representation corresponding to circle 11 in FIG. 1, a modified embodiment of the invention,
• Fig. 3 is a vertical section of the wall construction system of FIG. 1 with attached clothing, and
• 4 schematically shows the cross section of the special cassette profile used in the wall construction system according to FIGS. 1 and 3 to explain the dimensioning in the present example.

As illustrated in particular in FIG. 1, a wall construction system according to the invention has upright supports 1 which are arranged at a distance from one another, for example in the form of steel profile beams, to which essentially C-shaped cassette profiles 2 are fastened with their bottoms. The cassette profiles 2 are arranged horizontally and can be of great length, for example they can extend over the entire wall width, while the supports 1 are arranged at greater intervals and support each cassette profile 2 at these intervals. In the example, the mutual distance between the supports may be 1 8 m. Each cassette profile 2 consists in the manner also shown in FIG. 4 in particular from a lower flange 3, which forms the bottom of the C-shape, a long web 4 and a shortened web 5 on both edges of the lower flange 3, an upper flange 6 on the outer edge of the unabridged web 4 and a bend 7 on the outer edge of the upper chord 6. In the example, the width b _{u of} the lower chord 3 may be 1000 mm and the width b _{o of} the upper chord 6 90 mm. The height h _{1 of} the uncut web 4 may be 240 mm and the height h _{2 of} the shortened web 5 may be 145 mm, while the width b _{K of} the fold 7 may be 25 mm. All angles are at least approximately right angles, the webs 4 and 5 projecting in the same direction from the lower flange 3 and the bend 7 from the upper flange 6 in the direction of the lower flange 3. For functional reasons, the upper chord 6 lies on the same side of the web 4 as the lower chord 3, although it is of no functional importance.

Each cassette profile was bent accordingly from 1.5 mm thick sheet steel, which is available in a 1.5 m coil width. When using steel sheet of reduced thickness, it is of course also possible, for example, to produce by rolling instead of being produced by folding, the name of the folding 7 not necessarily implying a corresponding production on a folding machine. In the example, a mild steel St 37 with a yield stress of 331.0 N / mm ² , a breaking limit of 405.1 N / mm ² and an elongation at break of 22.52% was used as the steel sheet, the yield point of which could be increased by cold working, whereby the breaking stress and elongation values meet the requirements of DIN 1623, sheet 2. With a cassette profile 2 made of this material and produced in the manner described, in the installation position shown in FIGS. 1 and 3, an inertia moment of about 10 kNm / m and a load of wind suction resulted when the wind pressure applied, the upper flange 6 and the lower flange 3 swapping their functions, an moment of inertia of over 12 kNm / m. These extraordinarily high values are largely due to the fold 7 on the upper flange 6, which bears almost over its entire length and, in particular, results in an additional bend on the outer edge of the upper flange 6, so that its load-bearing width is increased. Without the bevel 7, the load-bearing width of the upper flange 6 is limited to the area of the edge between the web 4 and the upper flange 6, while due to the additional edge on the bevel 7 in the case of the dimensioning of the upper flange width b _o of 90 mm given as an example, this is almost the same carries the entire width of the upper chord 6 and the additional edge also increases the supporting area of the upper chord 6 on the other edge. It has been shown that the load capacity of the cassette profile 2 drops to only about 35% of the previous value, if only the fold 7 is omitted.

The cassette profiles 2 are mounted one above the other on the supports 1 in the manner shown in FIGS. 1 and 3, the unabridged webs 4 being at the top. As a result, a shortened web 5 of the other cassette profile 2 is adjacent and bolted to an unshortened web 4 of the one cassette profile 2. The type and position of the screw connections is indicated in FIG. 3 by dash-dotted lines, to which express reference is made. As a result of the shortening of the web 5, in the joint area between adjacent cassette profiles 2, the unshortened web 4 with the upper flange 6 and the bevel 7 is practically only load-bearing, while the shortened web 5 follows deformations, in particular bends of the web 4 in the vertical direction of the wall construction system without noticeable resistance. Compared to the same design of the webs 4 and 5, each with an upper chord 6, the web area is thereby weakened and elastically softer, so that in view of the large width b _{u of} the lower chord 3 of 1000 mm overall, acoustic decoupling and reduction of the structure-borne noise transmission between the the inner shell of the lower chords 3 forming the wall construction system and a cladding 8, which is illustrated in FIG. 3, and forms the outer shell of the sound-insulating wall construction system after attachment to the upper chords 6.

The cladding 8 consists in the usual way of trapezoidal sheet steel or aluminum with vertically running trapezoidal projections, between which the cladding 8 is fastened to the upper straps 6 with self-tapping facade screws. The trapezoidal sheets of the facade cladding 8 have a height that extends over a plurality of upper chords 6, as is illustrated in FIG. 3. In the example, each trapezoidal sheet field 8a, 8b and 8c may extend over the height of four cassette profiles 2, but larger heights of the springs 8a, 8b and 8c are also possible. The fields 8a, 8b and 8c are arranged such that the upper field z. B. 8a in an overlap area 9, the upper edge of the lower field z. B. 8b, with the lower end of the upper field z. B. 8a against the adjacent top chord 6 above the overlap area 9 or the upper edge of the lower field z. B. 8b is fixed by facade screws. Through the overlap area 9 and the attachment of the lower end of the upper field z. B. 8a on the adjacent top flange 6, the upper edge of the lower field z. B. 8b against a distance from the top chord 6, but is freely movable in the longitudinal direction, so that here with thermal expansion or heat shrinkage of the field z. B. 8b no voltages occur. At the other fastening points of the fields 8a, 8b and 8c on the upper chords 6 of the cassette profiles 2, stresses occur during thermal expansion or heat shrinkage, but these are safely absorbed by the facade screws, especially in the present example, since these have a sheet thickness of more than one in the one-piece lower chords than 1 mm, in particular in the present example case of 1.5 mm, are also securely anchored without any additional measures. As a result, corresponding tensions are transferred cleanly into the upper chords 6, which can be moved in parallel with respect to the lower chords 3 due to the increased elasticity and flexibility of the web regions, without excessive tension build-up. The unshortened webs 4 thus diverge to a certain extent by bending upwards or downwards and thereby reduce stresses due to thermal expansions or heat shrinking of the fields 8a, 8b or 8c.

In the area of the supports 1, cassette profiles 2 can, if necessary, be stiffened by stiffeners 10, as dash-dotted in FIG. 3 and visible in FIG. 1 with solid lines. This also avoids in the worst cases that the cassette profiles 2 collapse approximately due to the weight of the clothing 8 in that the webs 4 are pulled down due to their flexibility. Stiffeners 10 of this type, which in the example are designed as vertically installed stiffening walls, can be expedient in particular in the case of clothing 8 made of heavier steel sheet and can of course also have any other suitable shape. Since the stiffeners 10 are in any case limited to the area of the supports 1 arranged next to one another at a large distance, they functionally do not appear to be disadvantageous overall.

The upper cassette profile 2 according to FIG. 1 is shown as it is after it is attached to the supports 1. As can be easily seen, provisional weather protection of the interior already takes place as a result, so that hanging with tarpaulins or the like can be omitted. A layer 11 of insulating material, for example in the form of mineral fiber boards, is then introduced into the open interior of each cassette profile 2 on the side of the lower flange 3 facing away from the supports 1 and is fastened, for example, by gluing. Depending on the thickness of the layer 11, this results in a sound insulation value between 48 dB and 57 dB in the case of using mineral fiber boards. The thickness of the layers 11 is in any case less than the height of the unabridged webs 2, and expediently also somewhat less than the height of the shortened web 5, so that it fully supports the underside of the layer 11. After the layers 11 of insulating material have been introduced into the cassette profiles 2, the clothing 8 is assembled in the position illustrated in FIG. 3.

Not least as a result of the increased strength of the upper flange 6 due to the fold 7, the lower flange 3 is relieved and only contributes to a comparatively small extent; so is in any case the middle third of the lower flange 3 for the Strength without meaning. This makes it possible to provide the lower flange 3 with an opening, if necessary with a plurality of openings in the form of perforations 12, so that the lower flange 3 is designed in the manner of a perforated plate, as can be seen from FIG. 2. If the lower chord 3 perforated in this way is deposited with sound-absorbing material in the form of an adsorbent layer 13, for example made of mineral felt, the result is a corresponding soundproofing of the interior bounded by the wall. Such sound absorption is particularly important, for example, in the case of power plant nacelles, in the interior of which the sound level is to be reduced.

In order to achieve the airtightness of the construction despite the perforation 12 of the lower flange 3, a partition 14 is installed between the layer 11 of insulating material and the absorber layer 13. With regard to sound insulation, the partition 14 then acts instead of the lower flange 3 as the inner shell of the wall construction system. Given the spacing between the two shells from the point of view of sound technology, the construction depth of the cassette profiles 2 thus increases in the case of the embodiment according to FIG. 2 by the thickness of the absorber layer 13, which in the example may have a thickness of 40 mm.

The embodiment of the invention shown corresponds to all currently valid building regulations, such as the "Guidelines for facade cladding with and without substructure, edition 1975" and the draft of DIN 18516 "Exterior wall cladding", so that complex individual approvals can be omitted.

In a manner known per se, elastic bands 15 and 16 made of foam rubber are arranged between the webs 4 and 5 of adjacent cassettes on the one hand and between the upper chords 6 and the inner surface of the clothing 8 on the other hand, in order to further minimize structure-borne noise transmissions.

Claims (10)

1. Sound-absorbing wall construction system for industrial buildings to be constructed as steel or reinforced concrete skeleton structures, such as power plant buildings, featuring long, thin- walled cassette sections (2) to accomodate insulating material, which can be connected with each other to form a space-enclosing wall as well as with the columns (1) of the steel or reinforced concrete skeleton, and a bottom boom (3) that can be arranged horizontally and parallely to the columns (1) as well as angled webs (4), (5) on the two long sides of the bottom boom (3) and at least one top boom (6) angled off from one of the webs (4) which serves to fix a facing (8) covering the individual cassette sections (2) on the outside, characterized in that a bent-off edge (7) has been provided on the outer long edge of the top boom (6) of one of the webs (4) aiming in the direction of the bottom boom (3) and that the other web (5) is designed without a top boom and shorter than the first web (4).

2. Wall construction system in accordance with claim 1, characterized in that the shorter web (5) has a length (h₂) which preferably exceeds the thickness of the insulating material (layer 11) only slightly.

3. Wall construction system in accordance with claim 1 or 2, characterized in that the shortened web (5) is fixed to the web (4) [having the top boom (6)] of the neighbouring cassette section (2), preferably by means of an elastic intermediate layer (15).

4. Wall construction system in accordance with one of the claims 1 to 3, characterized in that the cassette section (2) consists of bent-off steel sheet having a sheet thickness of more than 1 mm, preferably not less than 1.5 mm.

5. Wall construction system in accordance with one of the claims 1 to 4, characterized in that the bottom boom (3) is provided with openings, particularly a perforation (12), at least in its central area.

6. Wall construction system in accordance with claim 5, characterized in that an absorber layer (13), particularly made of mineral felt, is located between a layer (11) of the insulating material, particularly in the form of mineral fiber boards, and the bottom boom (3).

7. Wall construction system in accordance with claim 6, characterized in that a partition (14), particularly made of sheet metal, is installed between the layer (11) of insulating material and the absorber layer (13).

8. Wall construction system in accordance with one of the claims 1 to 7, characterized in that a stiffening (10) offering the two webs (4, 5) protection against bulging is installed in individual cassette sections (2) transversally to their longitudinal direction.

9. Wall construction system in accordance with one of the claims 1 to 8, characterized in that the facing (8), particularly of trapezoidal sheet metal, is composed of panels (8a, 8b, 8c) which overlap each other with their edges running parallel to the longitudinal direction of the cassette sections (2) and that only the edge away from the cassette sections (2) in the overlapping area (9) is fixed to a neighbouring top boom (6).

10. Cassette section for a wall construction system in accordance with one of the claims 1 to 9, characterized by the characteristics of claims 1,2,4 and/or 5.

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