EP1236838A2 - Structure de plancher - Google Patents

Structure de plancher Download PDF

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Publication number
EP1236838A2
EP1236838A2 EP02445028A EP02445028A EP1236838A2 EP 1236838 A2 EP1236838 A2 EP 1236838A2 EP 02445028 A EP02445028 A EP 02445028A EP 02445028 A EP02445028 A EP 02445028A EP 1236838 A2 EP1236838 A2 EP 1236838A2
Authority
EP
European Patent Office
Prior art keywords
floor
floor structure
ceiling
structure according
joists
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02445028A
Other languages
German (de)
English (en)
Other versions
EP1236838A3 (fr
Inventor
Jan Strömberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plannja AB
Original Assignee
Plannja AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plannja AB filed Critical Plannja AB
Publication of EP1236838A2 publication Critical patent/EP1236838A2/fr
Publication of EP1236838A3 publication Critical patent/EP1236838A3/fr
Withdrawn legal-status Critical Current

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    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B9/00—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation
    • E04B9/04—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation comprising slabs, panels, sheets or the like
    • E04B9/0428—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation comprising slabs, panels, sheets or the like having a closed frame around the periphery
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B5/00—Floors; Floor construction with regard to insulation; Connections specially adapted therefor
    • E04B5/02—Load-carrying floor structures formed substantially of prefabricated units
    • E04B5/10—Load-carrying floor structures formed substantially of prefabricated units with metal beams or girders, e.g. with steel lattice girders
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B9/00—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation
    • E04B9/001—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation characterised by provisions for heat or sound insulation
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B9/00—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation
    • E04B9/06—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation characterised by constructional features of the supporting construction, e.g. cross section or material of framework members
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B9/00—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation
    • E04B9/18—Means for suspending the supporting construction
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B9/00—Ceilings; Construction of ceilings, e.g. false ceilings; Ceiling construction with regard to insulation
    • E04B9/18—Means for suspending the supporting construction
    • E04B2009/186—Means for suspending the supporting construction with arrangements for damping vibration

Definitions

  • the present invention relates to a floor structure comprising a load bearing floor part and a ceiling flexibly suspended from said floor part.
  • Light floor structures are mainly used at present in single unit dwellings and terraced houses.
  • the floor structures often comprise joists, most often wooden joists although the use of steel joists is also becoming more common.
  • the floor is often comprised of one or more layers of sheet material made from wood or gypsum. In the case of relatively wide joist spacings, profiled metal sheet may also be used on the joists beneath the sheet material, to increase rigidity.
  • the ceiling of the floor structure is comprised of sheets that are either screwed directly to the supporting joists or indirectly via slender cross-joists which, in turn, are fastened to the supporting joists. Sound-damping insulation consisting of mineral wool may be included in the floor structure.
  • This type of light floor structure has many advantages over traditional concrete floor structures.
  • the light floor structure is dry, i.e. no drying-out period is required as in the case of concrete, this latter lengthening the construction process.
  • Such floor structures are also light in weight, which results in cheaper transportation and lighter loads on other parts of the construction. They are also normally cheaper than concrete floor structures and have less detrimental effect on the environment.
  • a known method of improving air insulation and impact sound insulation so as to fulfil standard requirements for apartment floor structures is to suspend those joists to which the ceiling sheets are fastened in such a manner that they will hang so flexibly as to prevent acoustic vibrations from propagating as readily in the construction from floor to ceiling. This can be achieved by fastening the joist to the floor beams through the medium of a separate resilient suspension arrangement, or by fastening the joist so that it will be subjected to large local elastic deformations at its suspension points in the manner described further on.
  • a floor structure that includes a load-bearing floor part and a flexibly suspended false ceiling will at first swing significantly when the floor is subjected to an impact, for instance to a so-called heel stamp, and thereafter becomes progressively weaker.
  • the time during which such movement can be discerned may vary in relation to a number of factors, such as in relation to the force of the impact, the stiffness of the supporting beams, material properties, the sheet material, the span, etc., and is normally from between a half-second to two seconds.
  • the oscillation normally takes place in two dominating oscillation modes. The one mode causes the floor structure and false ceiling to oscillate in phase, while the other mode causes them to oscillate in counter-phase. Because the amplitudes are added together in the counter-phase oscillation mode, the work carried out by the suspension spring will be greater than in the case of oscillation in the phase mode, in which the oscillations are subtracted.
  • the floor structures are more flexible or "softer" than similar thick concrete structures. They are particularly flexible transversely to the bearing direction of the bearing joists. Spot loads in respect of light floor structures result in greater deflections than in the case of concrete floor structures. Such deflections can be limited, however, by using stiffer joists and placing them closer together. Steel joists are also preferable, since they can be made more rigid than wooden joists. This problem can thus be adequately overcome by constructive measures. A floor structure that is not excessively rigid is not solely a negative feature. A given degree of softness can be experienced as being comfortable.
  • a light floor structure is easily accelerated, and steel beams in particular have a small internal damping property, meaning that the vibrations will be felt over a long period of time, which is troublesome.
  • Attempts have been made to solve this problem with mass damping, i.e. with a heavy mass within the floor structure, which is coupled by a spring to said structure.
  • the spring has a rigidity which is tuned so that the oscillating energy in the floor structure will be transmitted to the mass via the spring.
  • Typical natural frequencies in respect of the first oscillation mode in the floor structure are 7-20 Hz. It has not been possible to obtain damping that functions in practice, since it is difficult to adapt the spring constant to the natural frequency of the floor structure, which, after all, depends on the span of the floor structure and its load. Tuning of the spring must lie close to the natural frequency of the floor structure, in order for the oscillation energy to be transferred. Moreover, the energy returns to the floor structure after a short period and meanders forwards and backwards until it fades away due to
  • the object of the invention is to provide strong damping of the kinetic energy in the floor, so that initiated vibration will die away more quickly and therewith not felt to be unpleasant.
  • This object is, in principle, fulfilled by viscous damping of the oscillating motion occurring between the suspended ceiling and the floor part.
  • the invention has the characteristic features set forth in the accompanying Claims.
  • the invention is inexpensive and easily applied. Moreover, it functions within wide limits with respect to span, load on the floor structure, rigidity of the floor structure, and the weight of said floor structure.
  • the invention enables light floor structures to be used for considerably wider spans than was earlier the case, typically spans of up to 6-8 m, and possibly larger, therewith enhancing its area of use and also its popularity.
  • FIG. 1 shows a method of achieving this.
  • Reference numerals 1 and 2 identify floor structure beams comprised of folded thin metal sheet, normally spaced 1.2 m apart. The floor structure element thus has a width of 1.2 m.
  • Reference numeral 3 identifies a trapezoidal profiled metal sheet that carries the load between the beams.
  • Reference numeral 4 identifies surface sheets that protect against fire and constitute an underlay for the floor covering.
  • Reference numeral 5 identifies cross joists having a centre to centre distance of 450 mm and supporting the ceiling sheets 6.
  • Reference numeral 7 identifies mineral wool which has a density in the range of 15-30 kg/m 3 and whose purpose is to dampen sound.
  • Figure 2 shows two mutually coupled elements.
  • Reference numeral 8 identifies a U-shaped fitting which fits into the trapezoidal profile and which is screwed firmly to the upper surfaces of said beams. The fitting holds the elements together. It may be practical not to fit the floor sheets before the floor structure elements have been fitted and screwed together.
  • Figures 3a and 3b respectively show two different methods of placing floor structure elements on a support, for instance on a primary beam or on a wall.
  • Reference numerals 9 and 10 identify alternative cross beams at the ends of the floor structure elements. These beams are screwed to the beams 1 and 2 via end angles 11 and 12.
  • Figure 4 is a longitudinal sectional view showing cross joists 5 which are folded from thin metal sheet having a thickness of about 0.5-0.7 mm and which support the ceiling sheets 6.
  • Figure 5 shows a part of one of the joists 5 and its suspension from the beams 1 and 2 of the floor structure.
  • the joist thus has a length of 1.2 m and is suspended at its ends.
  • the screw 13 is placed far from the web of the joist, to provide soft resilient suspension, such that the joist web will sag under the weight of the ceiling sheets.
  • a damper 14 which consists of a short angle 15 comprised of sheet metal having a thickness of about 2 mm and screwed with screws 16 close to its corners, so as to sit rigidly affixed to the undersurface of the beam.
  • a viscoelastic mass of high viscosity Located between the joist web and the angle 15 is a viscoelastic mass of high viscosity.
  • the viscoelastic mass may be butyl rubber, for instance the butyl rubber retailed under the trade name Terostat by Trelleborg AB.
  • the butyl rubber adheres to the metal surfaces.
  • Joist spacing is 450 mm and the length of respective joists is 1.2 m, meaning that the numbers will be about 1.9 times greater per m 2 .
  • the viscosity Cd is thus about 280 N/(m/s) per m 2 and the elastic rigidity of the damper is thus about 55 kN/m per m 2 floor structure surface.
  • the effect of the suspension spring rigidity and the elastically rigid part of the damper are added together
  • the viscosity is measured and given in N/(m/s), thus as though it is velocity dependent linearly. This is practical, because it simplifies the calculations and can be readily analysed, and tests have shown that the approximation is reasonable.
  • the viscosity may be non-linear in practice.
  • the viscous rigidity and the elastic rigidity may vary within wide limits and still provide effective damping. In respect of a floor structure that has an intrinsic weight of between 60 and 300 kg/m 2 , it is favourable if the ceiling weighs between 20 and 50% of the entire weight of the floor structure.
  • Figures 6 and 7 show how the butyl rubber is deformed by shear in response to relative movements between floor and ceiling.
  • Figure 8 illustrates frequency response measurements in tests carried out on floor structure elements according to Figure 1 having a length of 7.2 m, partly with 18, partly without 19, with damping 14 according to Figure 5.
  • Each of the bearing joists 1 and 2 has a moment of surface inertia corresponding roughly to 24x10 6 mm 4 .
  • This mode is only influenced to a small extent by the damping, since the damper is subjected to only a small degree of movement.
  • the frequency of this mode increases to 17.5 and damping is achieved to a very high degree.
  • Figure 9 shows how the state of the floor, curve 40, and the state of the ceiling, curve 41, change in response to a floor impact in the absence of damping between the beams of the floor structure and the ceiling joists, although with the internal damping which measurements show is nevertheless present in a similar floor structure. It will be seen that floor and ceiling still oscillate significantly after a lapse of one second, which is perceived as highly disturbing.
  • Figure 10 shows how the state of the floor, curve 42, and the state of the ceiling, curve 43, change in response to a floor impact in the presence of damping between floor beams and ceiling joists. It will be seen that floor and ceiling oscillate at a significantly smaller amplitude and at a lower frequency, i.e. at a lower velocity.
  • Figure 11 illustrates the acceleration of the floor in m/s 2 subsequent to an impact in the absence of a damper, curve 20, and in the presence of a damper, curve 21.
  • the significant influences of the dampers is clearly seen.
  • the effect on acceleration is greater than the effect on displacement. It is the acceleration that is discerned as disturbing, because, according to the laws of motion and according to the laws of kinematics, it produces the force that is felt by the person present on the vibrating floor structure.
  • Figure 12 illustrates the acceleration of the ceiling in m/s 2 subsequent to impact in the absence of damping, curve 22, and in the presence of damping, curve 23. It will be seen that the dampers have a significant influence even in respect of the ceiling.
  • Figure 13 shows the influence on the acceleration of the floor in response to making the elastic suspension spring about three times more rigid, e.g. by moving the screw 13 closer to the web of the joist 5.
  • Curve 24 shows a floor structure that is not dampened, while curve 25 shows a dampened floor structure. Although damping still functions, the effect is not as great.
  • the reduction in sound has been impaired by the stiffer suspension. We can perceive this as being an approximate limit in obtaining an almost sufficient effect in respect of this floor structure.
  • the sum of the stiffness of the suspension spring and the elastic part of the stiffness of the damper is, in the illustrated case, about 700 kN/m per m 2 of floor structure surface. This limit may be different in the case of other weights on suspended false ceilings and in the case of other conditions in general.
  • Figure 14 illustrates the effect on ceiling acceleration when the elastic spring is made about three times stiffer, for instance by moving the screw 13 closer to the web of the joist 5.
  • Curve 26 illustrates a non-dampened floor structure
  • curve 27 illustrates a dampened floor structure. Although damping still functions, the effect is not as great. Moreover, sound reduction has been impaired by the stiffer suspension.
  • Figure 15 illustrates the effect of an impact on the acceleration of the floor, by virtue of the combined viscosity of the two dampers per joist being reduced from 150 N/(m/s), curve 28, to 50 N/(m/s), curve 30.
  • Curve 31 illustrates a fully undampened embodiment. The curves show that damping has still a great effect down to viscous damping 50 N/(m/s) per joist, but that this effect is nevertheless significantly worse in comparison with the strong damping effect obtained with the described embodiment.
  • 50 N/(m/s) per joist corresponds to about 90 N/(m/s) per m 2 . Let it be said that a reasonable minimum limit for a functioning damping facility is 70 N/(m/s) per m 2 .
  • Figure 16 shows the effect obtained when solely the five centremost joists of the joists 5 of the floor structure element 15 have viscous damping, curve 32, instead of all the joists being dampened, curve 33, or when no joist is dampened, curve 34.
  • the comparison shows that effect is limited when the dampers on joists outwardly of the centre part are removed. The explanation is because movement is greatest in the centre.
  • the scope of the present invention also enables other types of dampers that have viscous characteristics to be used.
  • the floor structure is built-up from prefabricated elements with floor beams comprised of folded thin metal sheet as main supports.
  • the invention will function equally as well with floor structures that are built on site and with floor structures built with welded or rolled steel beams or wooden joists or concrete beams.
  • the supporting construction may also comprise longitudinally extending, trapezoidal-profiled metal sheet having a high profile height, normally above 100 mm.
  • the floor structure may even consist of concrete floor structures cast on site, with a resilient suspended false ceiling that has viscous dampened suspension. The limit values with respect to elastic and viscous rigidities must be adapted to the components and spans included in the structure.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Body Structure For Vehicles (AREA)
  • Floor Finish (AREA)
EP02445028A 2001-03-01 2002-02-27 Structure de plancher Withdrawn EP1236838A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0100716 2001-03-01
SE0100716A SE521850C2 (sv) 2001-03-01 2001-03-01 Bjälklag

Publications (2)

Publication Number Publication Date
EP1236838A2 true EP1236838A2 (fr) 2002-09-04
EP1236838A3 EP1236838A3 (fr) 2003-03-26

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EP02445028A Withdrawn EP1236838A3 (fr) 2001-03-01 2002-02-27 Structure de plancher

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SE (1) SE521850C2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE2051250A1 (en) * 2020-09-17 2022-03-18 Mitek Holdings Inc Floor joint system comprising a bracket for holding a suspended ceiling

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1001774A (fr) * 1949-12-02 1952-02-27 Dispositif de suspension isolant et anti-vibratile pour plafonds suspendus, utilisé dans l'industrie du bâtiment
FR1441910A (fr) * 1965-07-13 1966-06-10 Metalastik Ltd Attaches utilisables dans la construction de bâtiments
DE9320490U1 (de) * 1993-08-21 1994-09-08 Richter-System GmbH & Co KG, 64347 Griesheim Schwingungsabhänger
DE4314006A1 (de) * 1993-04-26 1994-10-27 Harald Dipl Ing Moews Federhänger zur schwingungsgedämpften Aufhängung von Lasten
JPH11100938A (ja) * 1997-09-29 1999-04-13 Natl House Ind Co Ltd 天井構造
WO2000052277A1 (fr) * 1999-03-02 2000-09-08 Owens Corning Systemes structurels attenuant les sons et panneaux associes

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1001774A (fr) * 1949-12-02 1952-02-27 Dispositif de suspension isolant et anti-vibratile pour plafonds suspendus, utilisé dans l'industrie du bâtiment
FR1441910A (fr) * 1965-07-13 1966-06-10 Metalastik Ltd Attaches utilisables dans la construction de bâtiments
DE4314006A1 (de) * 1993-04-26 1994-10-27 Harald Dipl Ing Moews Federhänger zur schwingungsgedämpften Aufhängung von Lasten
DE9320490U1 (de) * 1993-08-21 1994-09-08 Richter-System GmbH & Co KG, 64347 Griesheim Schwingungsabhänger
JPH11100938A (ja) * 1997-09-29 1999-04-13 Natl House Ind Co Ltd 天井構造
WO2000052277A1 (fr) * 1999-03-02 2000-09-08 Owens Corning Systemes structurels attenuant les sons et panneaux associes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE2051250A1 (en) * 2020-09-17 2022-03-18 Mitek Holdings Inc Floor joint system comprising a bracket for holding a suspended ceiling
SE544436C2 (en) * 2020-09-17 2022-05-24 Mitek Holdings Inc Floor joist system comprising a bracket for holding a suspended ceiling

Also Published As

Publication number Publication date
SE0100716D0 (sv) 2001-03-01
EP1236838A3 (fr) 2003-03-26
SE0100716L (sv) 2002-09-02
SE521850C2 (sv) 2003-12-16

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