FI66962B - LAETT BJAELKLAGSKONSTRUKTION FOER FLERVAONINGSBYGGNADER - Google Patents

Description

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Sweden-Sweden (SE) 7804503 ~ 6 (71) AB Gyproc, Box 505, 201 25 Malmö,

Ingemanssons Ingenjörsbyrä AB, Box 53037, AOO 14 Gothenburg 53,

Sweden (SE) (72) Bo Sigvard Hellborg, Genarp, Rolf Öhman, Malmö,

Stig Ingemansson, Mölndal, Stefan Einarsson, Lindome, Sweden-Sweden (SE) (7A) Lei tzinger Oy (5A) Lightweight subfloor structure for multi-storey buildings - Lätt bjä1klagskonstruktion för flerväningsbyggnader

The present invention relates to a lightweight, good soundproofing subfloor structure for use in multi-storey buildings, in particular for residential use, comprising a plurality of adjacent supported prefabricated beams with a span of between about 2 and about 6 m and a substantially uniform upper surface , which is supported at a distance below the load-bearing component, and preferably also a so-called soft floor covering on the upper side of the load-bearing component.

Prefabricated girder slabs are understood here as self-supporting elements that share the load in two rectangular horizontal directions, which are manufactured outside the building in which they will be placed to be lifted into the building frame currently being built and mounted side by side on necessary supporting walls or beams. Usually, such beam slabs are manufactured as reinforced casting monolithic joints, but other manufacturing methods may also be considered, albeit in exceptional cases. In this case, for example, it is possible to make them runnable by compression molding from a rigid concrete mass or by joining together several sub-elements, possibly of different materials, which are rigidly and permanently joined together by gluing, casting or the like to form a single unit. To the extent that these more unusual manufacturing methods come into play, it is essential in the context of the invention that the finished beam slabs behave in the same way as the monoliths.

Suspended ceilings are understood here as sound-insulating roofs in which, for example, the flexurally resilient plates form a unitary layer which is supported at a distance below the load-bearing component so that the plates delimit the space below the load-bearing component as it goes downwards.

By soft floor covering in this context is meant at least to some extent resiliently compressible coverings with one or more layers of factory-made tiles or webs. Examples are e.g. mention both carpets of so-called fibrous material - in particular carpets with a foam or foam base - and plastic carpets with a core or base of foam, thick linoleum or cork carpets, in particular with thick floorboard and a tread made of any kind of material.

The subfloor structure is light when its basis weight, including the suspended ceiling and floor covering, is well below 200 kg / m2 and, above all, below 150 kg / m2. Such a lightweight subfloor structure is particularly advantageous in that it reduces the load-bearing requirements of the building frame, thus providing far-reaching simplifications in the structure that advantageously affect the economy of the entire building. In addition to this, there is the added advantage that beam slabs belonging to such a building must, of course, have a low basis weight, which facilitates their handling and connection to the building frame and, moreover, imposes only reasonable requirements on construction site crane equipment.

3 66962

However, in multi-storey buildings, especially for residential use, a significant proportion of all mezzanine structures must meet certain minimum requirements for sound insulation between storeys and often also by the authorities. In setting these minimum requirements, a distinction is made between airborne noise and footstep noise, which, as is known, have different characteristics and which must therefore be attenuated, at least in part, by different types of measures. Even very high airborne sound insulation requirements can usually be met with lightweight subfloor structures without major difficulties. In contrast, the problems become much more difficult when it comes to step sound insulation.

The minimum requirements for the step sound insulation of subfloor structures are usually given as numerical values obtained by applying certain measurement methods. Although the measurement methods commonly used today give objective readings of step sound insulation at several step sound frequencies - they are in part incomplete, as shown by the fact that in certain common subfloor structures the step sound insulation is subjectively assessed as insufficient, despite the fact that the measured values Certain experimentally constructed, relatively light subfloor structures have been able to provide step sound insulation with standard measurement methods that objectively meets even the highest requirements set by the Swedish authorities for step sound insulation in a subfloor structure that separates these two overlapping subfloors subjectively completely inadequate, especially at frequencies below about 200 Hz.

In fact, today there is no lightweight subfloor structure - in any case not as presented in the introduction - which, both subjectively and objectively, has a satisfactory sound insulation capacity to meet the requirements that are or should be placed on the subfloor structure in dwelling 4-storey in distinctive rewards.

The only surefire way known to those skilled in the art of construction to achieve good step sound insulation for a subfloor structure is to form heavy subfloor structures - usually at least 300 kg / m2 and often significantly more. Where such girder structures are not constructed using ordinary reinforced concrete girder slabs with a minimum thickness of about 15 cm, the high basis weight must be achieved by additional mass-increasing measures, such as additional castings, sand layers or so-called "floating floors", which naturally causes difficulties. Even when using a reinforced solid concrete beam slab with a thickness of about 15 cm, a soft floor covering is required to meet the highest step sound insulation requirements. In either case, of course, the advantages provided by the lightweight subfloor structure in the sense that the building frame can be simplified and reduced, since the weight per square meter of the subfloor structure is more than 350 kg / m2 despite the absence of a suspended ceiling, are not achieved.

The only way to reduce these large basis weights while maintaining good step sound insulation in the midsole structure, which could possibly be tested by a person skilled in the art, would be to supplement a soft floor cladding with a suspended ceiling of the type described in the introduction. However, such a structure would not be able to meet reasonable practical requirements, as the maximum span of the thinner concrete slab would be about 2.5 m, i.e. it would go in the immediate vicinity of the lower limit of the spans required in practice. In practice, therefore, almost invariably, mass-increasing stiffeners are required on the underside of the beam slab, with the result that the complete midsole structure has a basis weight of well over 200 kg / m2 to reach even close to about 6 m spans, and often exceeds 300 kg / m2. The reduction in basis weight achieved in this way is thus practically far too small to compensate for the complexity which the use of a suspended ceiling always brings.

5 66962

The problem to be solved by the invention is to provide a complete beam structure which, despite its low basis weight - with spans considerably less than 200 kg / m 2 with spans of up to about 6 m - has an exceptionally good step sound insulation - both subjective and objective. In solving this problem, the invention starts from the known situation that soft floor coverings practically do not attenuate step sound at frequencies below 600 Hz and in most cases suspended ceilings of the type previously defined provide insufficient effect at frequencies below 250 Hz, while at higher frequencies both an effect that becomes particularly noticeable and useful at frequencies of about 800 Hz and above. Furthermore, the invention starts from the equally known fact that the sensitivity of the human ear is relatively low when the frequency of sounds is below 50 Hz and above all below the limit of 20 Hz, which means that no measures normally need to be taken to attenuate such very low frequency sounds.

From the above point of view, the invention solves the presented problem in that each of the beam slabs belonging to the load-bearing component of the subfloor structure, despite a very low basis weight - in any case less than 150 kg / m 2 - has properties such that no small part has a basic resonance frequency of less than 600 Hz. 800 Hz, while at the same time the plate as a whole has a basic resonant frequency of at most 50 Hz and, above all, at most 20 Hz in the actual span.

It is clear that the solution of the problem just presented requires the use of beam slabs, the design of which has been chosen with great regard to static load-bearing capacity and indeed acoustic requirements, where the relationship between slab stiffness and its effective span is naturally decisive for lower frequency. It can be seen quite quickly that it is the shape of the beam slab that is decisive, since although the use of a material with a lower specific gravity than the concrete normally used in beam slabs can provide certain practical advantages, it alone cannot lead to any absolute solution. the flexural strength always depends to a large extent on the modulus of elasticity of the material contained therein, which usually decreases sharply as the specific gravity decreases.

With regard to the design of the beam slab used, a substantial part of the small amount of material used must be used to achieve a large horizontal dimension of the slab, while the requirement for static load-bearing capacity in the span must be met by another, equally essential material part. This means that for most of their total area, the thickness of the beam slab must necessarily be extremely small. At first sight, such a small thickness over a large area seems to be in clear contradiction with the previously mentioned requirement that all minor parts of the beam plate must have a high basic resonant frequency.

However, according to the invention, it is possible to meet the requirement of a high fundamental resonant frequency by dividing the very thin surface area of the beam plate far and simultaneously stiffening the beam plate as a whole in two preferably rectangular directions, preferably in the span direction and transversely. The flexural strength of the slab in both these directions should then preferably be approximately equal, and in any case the transverse flexural strength in the transverse direction should not be less than a quarter of the flexural strength in the span direction. Most important, however, is the relationship between the shape and thickness of the small thin slab parts and the relationship between said shape and the vertical static strength of the stiffeners which separate the small thin slab parts from each other. Of course, from the point of view of low basis weight, it is also important that the part of the beam plate material required to meet the static load-bearing requirement in the direction of the span is at the same time utilized in the optimal expansion to form said stiffeners.

7 66962

In a preferred embodiment of the midsole structure according to the invention, beam slabs of the type are used which, in addition to said low basis weight, have such a general shape that each slab has at least a nearly uniform thickness plate-like part with a substantially flat top surface and a grid of reinforcing flanges extending over it. part of the two rectangular reinforcing directions so as to delimit a large number of downwardly open, at least largely quadrangular compartments arranged in several parallel rows in each reinforcing direction, the plate-like part over each of these compartments being tightened by a part marked as "lower bases", is a dimensional portion coincident with the cash of the first reinforcement direction and a dimensional portion coincident with the second reinforcement direction, one of which is not more than 50% larger than and preferably equal to the other, in which case is that the minimum dimension of the lower panels is at most 20 times the square root of the thickness of the plate-like part and the lower panel, expressed in cm, which is less than 4 cm, and that the minimum height of the reinforcing flanges is at least half the minimum dimension of the lower panels.

It should be noted here that said general shape of the beam slabs, which preferably belong to the intermediate floor structure according to the invention, to a certain extent resembles the shape that has been applied for decades to concrete girder slabs with a high basis weight. However, in the case of these heavy girder slabs, the shape did not depend on any acoustic aspects and, above all, on the requirements to achieve a certain step sound insulation in the slabs, but only on the static aspects caused by the large spans. In these known beam tiles, the step-sound insulation capability is obtained either by greatly increasing the thickness of the plate-like part or is subsequently achieved by means of "floating floor" or heavy-duty upper floor structures of a similar type. In addition, extensive literature reviews conducted after the invention was made to confirm its novelty have purely coincidentally found a type of exterior roof tile that, in certain variants, could potentially meet the beam tile requirements of the invention. In these known exterior roof tiles, however, the issue of step sound insulation was not relevant at all, but the shape of the tile was mainly due to static, but also partly to aesthetic aspects.

In order to explain the invention in more detail, a couple of exemplary embodiments will be described in the following description with reference to the accompanying drawings, in which:

Figure 1 is a partial vertical section of a first midsole structure according to the invention.

Figure 2 shows the same structure seen from below and the suspended ceiling partially removed to show the underside of the beam slab.

Figure 3 shows, on an enlarged scale, a fragmentary vertical section of the beam plate itself, in which certain dimensions relevant to the invention are marked.

Figure 4 is a partial vertical section of another midsole structure according to the invention.

Fig. 5 is a vertical section along the line v-v in Fig. 4.

Figure 6 shows a part of the subfloor structure according to Figures 4 and 5 seen from below and the suspended ceiling partially removed.

Figure 7 shows, on an enlarged scale, a fragmentary vertical section of the beam plate itself, showing part of Figure 5, with certain dimensions relevant to the invention being marked.

The midsole structure shown in Figures 1 and 2 comprises, as a load-bearing component, a prefabricated girder tile, generally indicated by reference numeral 10. This girder tile supports a floor covering layer 11 on its upper side, which is, for example, a foam-based plastic mat. Suspended under the beam slab is a suspended ceiling, generally indicated by reference numeral 12, consisting of two layers of gypsum board 12A and 12B, each having a thickness of about 13 mm. The suspended ceiling 12 is supported by a lattice structure connected together by a series of mutually intersecting steel plate profiles 13 and 14 and suspended from the beam plate 10 by flexible pendulums 15, such as steel strip or steel wire, the suspension being such that the joint between the beam plate and the suspended ceiling does not form a butt joint. Alternatively, the truss structure could be kept completely separate from the beam slab 10 and supported by suitable support strips arranged along the walls around the space under the subfloor structure. Importantly, the suspended ceiling substantially airtightly limits the space under the beam slab 10 as it goes downward, and that the gypsum boards 12A and 12B included in the suspended ceiling are able to perform their flexurally resilient pivoting motion more or less unimpeded.

The beam plate 10 itself has at least a nearly uniform thickness of the plate-like part 16, the upper side of which is substantially flat, but on its lower side there is a grid of reinforcing flanges 17 and 18 extending over the entire plate-like part 16 in two mutually perpendicular directions so that the flanges delimit several downward openings, four-edged compartments that are substantially equal in size and located in a plurality of parallel rows extending in each of the two reinforcement directions. Each such compartment is then covered by a small square portion of the plate-like portion 16, referred to herein as the "bottom panel". Such a lower panel is denoted sp in Fig. 2, and all these lower panels are equal in size and have a side dimension of s. As can be seen in Fig. 3, the plate-like part 16 has a thickness t, while all reinforcement flanges 17 and 18 have a height h and a base width b near the underside of section 16.

According to the invention, t is now less than 4 cm and s is at most 20 times the square root of t, expressed in centimeters, while h is at least half as large as s. Moreover, the flange width b is suitably less than the double thickness of the plate-like part 16 66962 t Finally, the beam slab according to the invention has a basis weight of less than 150 kg / m 2. Under these conditions, the resonance or natural frequency of the beam plate 1 as a whole is well below 50 Hz and in most cases about 20 Hz, while the lower panels have a resonant frequency well above 600 Hz and in fact very close to or above 800 Hz.

In practice, for example, t can be 2.5 cm, b 4.0 cm, s 26.0 cm (i.e. clearly smaller than: 20 V 2.5), while h can be 17.5 cm, so the total height of the beam plate becomes 20, 0 cm. It should be noted, however, that the same size sp of the bottom panel can in principle be applied, even if the thickness t is only about 1.7 cm. One reason why the value of s is chosen to be exactly 26 cm is that the mean distance between the reinforcing flanges then corresponds to the basic module dimension 3M = 30 cm, which is often used in the construction industry. By placing the reinforcing flanges somewhat more tightly than shown in the basic view, naturally also greater strength is obtained both in the beam plate as a whole and in the lower panels. On the other hand, the height h of the reinforcing flanges chosen as an example should be able to be chosen to be 4.5 cm smaller without the acoustic properties of the slab deteriorating too much. In the example shown, the flange height can therefore be considered to have been chosen above all, taking into account the desired span, which is required to be up to about 3.5 m. For manufacturing reasons, it is often advantageous to select the same flange height in both reinforcement directions for spans so dimensioned, although only span direction.

In the example shown, the beam slab 1 is thought to be cast from a hydraulic binder-based casting mass which is slightly porous in the cured state and has a specific gravity of about 1600 kg / m 2, in addition to which the mass is thought to be reinforced at least near the lower edge of reinforcement flanges. For this reason, the basis weight of this beam slab can be estimated with the given dimensions of about 105 kg / m 2. In this case, the total basis weight Ola of the midsole structure shown in Figs. 1 and 2 should be of the order of 130 to 140 kg / m 2. Likewise, its step sound insulation capacity should be equivalent to that of a 11 66962 subfloor structure with a load-bearing component of 8.3 cm thick, solid and reinforced concrete slab with span-reinforced reinforcements on the underside to provide equivalent load-bearing capacity and similarly fitted with a soft floor covering. with a suspended ceiling 3 of the same type as in the example described. The total basis weight of such a fully comparable midsole structure, built on hitherto known principles, should be about 250 to 260 kg / m 2, so that the structure would be almost twice as heavy as the midsole structure according to the invention.

In the exemplary embodiment of Figures 4-7, the load-bearing component of the intermediate base structure is formed from a plurality of side-supported beam slabs 20, the embodiment of which is slightly modified. A soft floor covering 21 is placed on the upper side of these beam tiles, which can be thought of as a rather thick carpet, in which case it can be, for example, a knitted mat with a so-called foam waffle as a base. In addition, a lower roof 22 is arranged on the underside of the load-bearing component, which in this case consists of only one layer of airtight gypsum boards with a thickness of about 13 mm. These gypsum boards are attached to a plurality of so-called insulating latches arranged parallel to each other at a distance of about 60 cm from each other on the undersides of the beam slabs 20, to partially load-bearing corner profiles 24 arranged on walls extending around the space below the subfloor structure. The outer edges of the suspended ceiling are substantially hermetically connected to these corner profiles. Reference numeral 25 has a part of such a wall shown in Fig. 5, which simultaneously acts as a support member for the beam slabs 20 belonging to the intermediate floor structure. Nk. the insulating latches 23 are formed of a thin steel sheet so that the connection between the gypsum boards forming the suspended ceiling and the beam tiles is formed to some extent. In addition, the rather flexible clamping latches clamp freely between the fastening points against the beam plates, which are spaced about 40 cm apart. In this case, the suspended ceiling 22 in Figures 4-6 functions in an acoustic function similar to the function of the suspended ceiling in Figures 1 and 2, although it is not entirely as good.

The beam plates 20 of the example of Figures 4-6 differ from the beam plates 10 of the example described earlier in that the underside of their plate-like top 26 has two groups of reinforcing flanges of different heights, namely a first group of transverse transverse reinforcing flanges 27 and 28, with a lower height h ', and another group of span-extending reinforcing flanges 29 and 30 with a higher height H. The lower flanges are designated by reference numeral 28 as the end edges of the beam slabs and the higher flanges by reference numeral 30 by the following longitudinal edges. The height of the higher flanges in the vicinity of the ends of the beam slabs is lower to correspond to the height of the lower, transverse flanges, thus simplifying the placement of the beam flanges on the load-bearing elements of the building frame, e.g. Both groups of reinforcing flanges form a substantially regular network or grid with downwardly open compartments, in this case rectangular so that each "bottom panel" - denoted in Figure 6 sp '- has the largest dimension or length 1 transversely to the span of the beam plate and the smallest dimension or width w in this span direction.

If, as in the example now shown, it is at most 50% larger than w, according to the invention it is sufficient that the size of the lower panel is in a certain way adjusted to the thickness t 'of the plate-like part 26, corresponding to the width w of the lower panel. If, on the other hand, 1 in a certain case, which should preferably be avoided, were more than 50% larger than w, it would be necessary to tighten the maximum size requirements for w to perhaps 15 or even 10 to 20 V t 'for acoustic aspects to ensure the necessary beam strength.

In the example of Figures 4-7, it can be assumed that t 'is 3.0 cm, while d' is 4.0 cm. with the value of t 'being mentioned, w should then be about 34.5 cm, but can only be considered selected for 26 cms to ensure that the slab receives the required strength transverse to the span direction, the height h' of the transverse reinforcement flanges 27 and 28. can be thought of as 15.0 cm, although according to the invention it should be possible to be somewhat lower, namely half of w. The height h 'of the reinforcing flanges 29 and 30 extending in the direction of the span 13 66962 is substantially greater than h', namely in the conceivable case 21.0 cm because the beam plate 20 exceeds a span of about 5 m wide. The base width of the higher reinforcing flanges 29 may suitably be about 7.0 cm. As in the previous example, the required tilt is formed on all trays.

With said dimensions, the beam plate 20 itself, if it is made of the material mentioned in connection with the beam plate 10 according to Figures 1-3 and provided with the necessary reinforcement, should have a basis weight of slightly more than 120 kg / m 2 despite a relatively large span. This would mean that the complete midsole structure of Figures 4-7, including the soft floor covering 21 and the relatively simple suspended ceiling 22, would have a basis weight of just under 140 kg / m 2. The step sound insulation capacity of this complete subfloor structure corresponds to that of a subfloor structure with the same floor covering and suspended ceiling and an 8.6 cm thick concrete slab, which, however, should be , which would be about 160 kg / m 2.

It should be apparent from the examples presented that many modifications can be made within the scope of the invention without losing the desired beneficial acoustic effect. It should be noted, however, that the advantages provided by the beam shape according to the invention are practically considerable at reasonable spans - up to about 6 meters - and at a thickness of less than 4 cm of the plate-like part 16 and 26 of the plate slab, respectively. Namely, at a larger span, the mass of the required reinforcement flanges begins to strongly dominate, whereby the weight saving becomes less and less significant. At higher thicknesses of the plate-like part, the mass of this part, on the other hand, begins to dominate at a lower span spacing, and in the meantime difficulties arise in order to ensure the upper limit of the lower fundamental resonant frequency of the beam plate.

Claims (5)

66962 14 A lightweight subfloor structure with good step sound insulation for use in multi-storey buildings, in particular for residential use, comprising a plurality of adjacent prefabricated beam slabs (10, 20) with a span of between about 2 and about 6 m and a substantially uniform top surface In addition to the component, there is a suspended ceiling (12, 22) spaced below the load-bearing component, and preferably also a so-called soft floor covering (11, 21) on the upper side of the load-bearing component, characterized in that the beam slabs (10, 20) forming the load-bearing component They have a weight of less than 150 kg / m 2 and at the same time are shaped such that the base resonant frequency of the midsole plate as a whole as well as the base resonance frequency of each part of the midsole plate is outside the frequency range of 50 to 600 Hz, preferably outside the frequency range of 20 to 800 Hz. Midsole structure according to Claim 1, characterized in that the general shape of the beam slabs (10, 20) is such that they each have at least a nearly uniform, plate-like part (16, 26) with a substantially flat upper side and reinforcing flanges ( 17, 18; 27-30) a grid extending substantially over the entire plate-like portion in two intersecting reinforcement directions so as to define a plurality of downwardly open compartments located in a plurality of parallel rows in each reinforcement direction, with the plate-like portion on each compartment tightening " part (sp) having a dimension extending in the first direction of reinforcement (s or 1) and a surface extending in the second direction of reinforcement (s or w), the former being at most 50% larger and preferably equal to the latter, the lower the dimension (s or w) is not more than twice the square root of the plate-like part and the bottom panel of thickness (t) expressed in centimeters, which thickness is less than 4 cm, and the minimum height (h) of the reinforcing flanges is at least half equal to said minimum dimension of the lower panels. 15 66962 Midsole structure according to Claim 1, characterized in that at least some of the reinforcing flanges (29, 30) extending in the direction of the span of the beam slabs (20) have a higher height (h) than other reinforcing flanges (27, 28) on the underside of the plate-like part (26). . 1. The method of construction of a vehicle is designed to meet the requirements of the invention, the construction of which is provided by the same component as the manufacturer, 6 m and with a practical tag on the side of the armrest (12, 22), which is set up as a cross-sectional component, as well as on the other side of the armrest (11, 21). the component component of the signal plate (10, 20) is less than 150 kg / m1 and is also equipped with a ground resonant frequency of the signal plate at a frequency equal to or greater than 50 times the ground frequency of the signal the transmission frequency is between 20 and 800 Hz. Bjälklagskonstruktion enligt krav 1, kännetecknad av, at The beam plate platform (10, 20) is provided with a generic form-shield, which can be stored in the atminstone of the jign-tjock, in the form of (16, 26), the arm is shifted from below to the end, and the medium is shaken soon. av förstyvnings-flänsar (17, 18; 27 - 30), in which case the interest in the form of a block is shown in the case of a third-party network, and in the case of a parallel line of the same radar, that is, and that is, the light is shielded from the span form of the sAsom "subpanel" betecknat parti (sp), som har en med den ena förstyvningsriktningen sammanfallande dimension (s eller 1) and en med den andra förstyvningsriktningen samman-