The invention relates to a steel structural system for erecting stories of buildings, especially stories containing dwelling rooms, work rooms or rooms for accommodating household appliances.
Steel structures are very rarely encountered in home construction. One important reason why is the exceedingly good ability of steel to transmit structure-borne noise, which is undesired in home construction.
Known in the art is a steel structure in which a balcony carrier is screwed to a building structure with a polyethylene plate interspersed. In addition to dissipating heat, the polyethylene plate has a slight insulating effect on the structure-borne noise. The disadvantage to this structure is that the balcony carrier and building structure have flanges with through holes for screwed joints. The screwed joints exhibit several screws pre-stressed with nuts, which penetrate through the flange and polyethylene plate. In this solution, structure-borne noise is transmitted unimpeded, at least via the screw shanks. Furthermore, with this solution, the resonance frequency of a massive plate made out of polyethylene is much too high to achieve an acceptable reduction in structure-borne noise transmission.
The object of the invention is therefore to provide a steel structural system that is easy to manipulate and connect, which almost completely prevents the transmission of structure-borne noise between individual stories, while at the same time still satisfying all requirements placed on the strength of the building structure in terms of structural statics.
This technical problem is resolved according to the invention by virtue of the fact that at least one floor structure and one ceiling structure is provided, that each ceiling structure serves as a floor structure for an additional story, that load-bearing story supports are arranged on the floor structure, and the ceiling structure rests on these story supports, that an elastically sound-dampening joining system is provided, which joins each of the story supports with the floor structure, that the joining system has a securing element, which is provided for laterally fixing the story support to the floor structure, and is joined to the floor structure, that the joining system exhibits a separating layer made out of flexible material with a high degree of resilience when deformed and a low plastic long-term compression, and that the separating layer is arranged between the securing element joined to the floor structure and the story support.
In particular the story supports as well as the floor and ceiling structure support beams are made out of steel. The perceived big advantage to the steel structural system according to the invention lies in the fact that the steel structural components of the individual building stories are separated from each other by the separating layer comprised of a flexible material, wherein no metal screw joints, in particular, are used. The transmission of structure-borne noise is eliminated or drastically reduced by virtue of the fact that the flexible material exhibits a high resilience when deformed, as well as a low plastic long-term compression. When installed, such a material exhibits a resonance frequency not exceeding 15 Hz under a permanent pressure exerted by the building story resting thereupon. Only this technical measure has made it possible not to transmit the structure-borne noise arising within a story structure into an overlying or underlying building story. The separating layer made out of flexible material here performs two functions. First, it decouples the bottom of the story support resting on the floor structure from the floor structure. To this end, the separating layer is arranged in a horizontal plane between these two building sections. Secondly, the securing element used for laterally fixing the story support is elastically decoupled from the story support in essentially a radial direction of the latter. To this end, at least sections of the flexible securing element are laterally provided with the separating layer, so that the story support only contacts the securing element indirectly via the separating layer.
One property of the flexible material comprising the separating layer is that its resonance frequency rises as does the permanent pressure under which the separating layer is compressed. The highest permanent pressures are reached on the section of the separating layer arranged in the horizontal plane, which separates the bottom of the story support from the floor structure. The entire building story or even several building stories here rest on the separating layer. Buildings with a low number of stories can be erected today with the currently available flexible materials. In higher buildings, the sustainable permanent load exerted on the flexible separating layer by the weight of the building and interior fittings can become too great.
The permanent pressure cannot exceed a specific limit, at which the flexible material still exhibits a resonance frequency of about 15 Hz, for example. At resonance frequencies exceeding the respective limit, the desired sound-insulating effect of the flexible separating layer is no longer achieved to the extent sought. Of course, applications in which the resonance frequency to be achieved can even be a bit higher are conceivable, because the resultant transmittable structure-borne noise can be tolerated. This can be the case in work rooms, for example, in which an elevated noise level prevails anyway. A better material might also become available in the future, which yields the desired low resonance frequency at even higher permanent pressures as the material existing today.
In addition to the reduced structure-borne noise transmission, the steel structural system according to the invention also provides for particularly good electrical insulation and seamless thermal insulation.
The steel structural system according to the invention comprises separating layer material of varying qualities. The separating materials are categorized into permanent load ranges for which they can be used. In multi-story buildings, the lowermost story must use material that can withstand the permanent pressure of all overlying stories and interior fittings, for example at a required resonance frequency of <15 Hz. The overlying story is decoupled with a separating layer material that reaches a resonance frequency of <15 Hz at a lower permanent pressure. The varying qualities of the separating material can be color or letter coded to prevent mistakes during assembly.
Provided in this way is a steel structural system based on a modular concept, with which building stories, in particular stories with dwelling rooms, work rooms or rooms for accommodating household appliances, can be erected especially quickly. In addition to the static requirements for the separating layer material, the story heights and spans between the story supports are best prescribed in increments. Separating layers varyingly dimensioned in terms of their geometry are available for different load classes. The proposed steel structural system not only facilitates the erection of building stories, but also streamlines permits with respect to structural statics, since evidence relating to structural statics can be categorized and transferred from one construction project to another.
In a structural steel system whose story supports have a self-contained, tubular section, the securing element of the joining system is favorably designed as a securing mandrel, and the securing mandrel placed on the floor structure projects into the clear of the story support resting on the floor structure. The story support is particularly simple to assemble, because no additional joining element, such as a screwed joint, is required. Another benefit stems from the fact that all sections of the joining system are incorporated inside or underneath the story support in a completely assembled state, and a smooth, tubular floor support is present for purposes of further expansion and erection of the wall structure over the entire height of the story.
To improve manipulation even further, it is helpful for the separating layer to be designed as a hat-shaped separating element, and exhibit a separating collar that resembles the brim of a hat, that the separating layer be placed on the securing mandrel, and the separating collar of the separating layer be arranged between the face of the floor support resting on the floor structure an the floor structure itself. Despite the functional separation of the separating layer into an area situated in a horizontal plane between the floor support and floor structure and an area that decouples the floor support in a radial direction from the securing element of the joining system, a hat-shaped, one-piece separating element is best used for ease of manipulation.
Also useful is a securing mandrel shaped like a truncated cone, and a floor support provided with a frontal centering receptacle, which interacts with the truncated cone of the securing mandrel via an interspersed separating layer. A coaxial layer between the floor support and securing mandrel is ensured in this way. This technical measure also simplifies the erection of the building, since the truncated cone acts as a guiding aid when setting the floor support onto the securing mandrel. The relatively heavy floor supports are normally positioned over the joining point by means of a hoist. The guiding aid simplifies assembly for the erecting engineer, who must guide the floor support onto the securing mandrel by hand. In addition, the guiding aid makes it possible to assemble the steel structural system more quickly. In terms of sound decoupling, the advantage to the truncated cone of the securing mandrel is that the circular projection surface of the cone, arising when viewed from above, absorbs some of the compressive load acting in the longitudinal direction of the story support. This tends to reduce the compressive load in the area of the separating layer arranged in a horizontal plane. This is accompanied by a reduction in the permanent pressure load and resonance frequency of the separating layer.
Another measure for abating noise inside a building story is achieved by filling the tubular section of the story support with concrete. In this way, the tubular story support assumes the property of a sounding board, which radiates sound when excited in whatever way, like the resonating body of a musical instrument. Further, a concrete-filled story support increases the fire safety of the building. This is because the danger of a dropping modulus of elasticity for the steel tubular steel of the story support during a rise in temperature is ameliorated. In the event of fire, the concrete absorbs a considerable amount of heat, which otherwise would cause the temperature of the story support to rise very rapidly, and diminish the stability.
One alternative embodiment of the steel structural system can exhibit a story support with a massive rod or an open section, wherein the securing element abuts the story support laterally from outside with the separating layer interspersed, and is joined with the floor structure. Possible sections include T-beams, double T-beams or U-beams. The interstices of such beams can also be provided with concrete.
Beams with open sections most often have flat surfaces arranged at right angles relative to each other, so that wall elements, windows and other structural elements can be more easily positioned than, for example, on story supports with a round cross section.
The flexible material of the separating layer preferably has a dynamic modulus of elasticity between 4 N/mm2 and 8 N/mm2. The flexible material of the separating layer advantageously consists of expanded polyurethane with a closed-cell structure. As has been shown, this material has the load-bearing capabilities required in terms of structural statics on the one hand, and its cell structure with gas-filled cells makes it useful for decoupling sound.
Another benefit is derived from expanded polyurethane having a cell framework that enables the high resilience of the separating layer after deformed. In another type of foamed material, the resilience stems from the inner pressure of the gas filled into the foam cells. Since the relatively thin-walled foam cells never tolerate a high inner pressure, the resilience of such foamed materials is very limited, and the latter exhibit distinctly higher compression sets after exposed to a compressive load. This is different for the proposed expanded polyurethane. As mentioned, expanded polyurethane derives its resilience from the cell structure itself, and therefore retains its resilience and low resonance frequency for a long time virtually unchanged, even under a permanent load.
In a modification of the steel structural system, an additional separating layer is arranged on the end of the floor support facing the ceiling structure, which brings about a sound decoupling relative to the ceiling structure. The additional separating layer hence sound decouples the story support at its end facing the floor structure by way of the joining system, as well as at the end facing the ceiling structure.
To simplify matters, the ceiling structure has secured to it a joining element facing the floor structure, with which the ceiling structure rests on the story support with the additional separating layer interspersed.
In order to laterally fix the story support on its end facing the ceiling structure as well, both the story support and the additional separating layer extend over the joining element secured to the ceiling structure.
Finally, a joining system for the sound-decoupled securing of a story support on a floor structure or ceiling structure is proposed, with a securing element attachable to the floor structure or ceiling structure for the lateral fixation of the story support, and a separating layer made out of flexible material, which exhibits a high resilience when deformed, and a low plastic long-term compression.
The invention shall be illustrated by example based on a drawing and described in detail based on the individual figures below: Shown on:
The joining system 4 has a securing element 5, which is provided on the floor structure 3 for laterally fixing the story support 2, and rigidly attached to the floor structure by screws 6. The joining system 4 has a securing mandrel 7 shaped like a truncated cone, which is provided with an attachment plate 8. The attachment plate 8 has holes 9 for accommodating the screws 6, with which the securing element 5 is fixed to the floor structure 3. The securing mandrel 7 and attachment plate 8 are enveloped by a separating layer made out of flexible material with a high resilience when deformed, which is designed as a hat-shaped separating element 10. The separating element 10 has a separating collar 10a that resembles the brim of a hat, which extends in the horizontal plane of the floor structure, and sound decouples the latter from the face of the erected story support 2.
The area 10b of the separating element 10 abutting the securing mandrel 7 shaped like a truncated cone contacts a pot-shaped centering receptacle 2b, which sits in the clear of the story support 2. It is approximated to the shape of the securing mandrel 7, and rigidly attached to the tubular wall of the story support 2. In this way, the story support 2 is both laterally fixed, and sound-decoupled in the radial direction from the securing mandrel 7 joined with the floor structure 3. The centering receptacle 2b also conforms to one side of the separating element 10, as the securing mandrel 7 does to the opposing side of the separating element 10. The centering receptacle 2b forms a floor inside the story support 2, up to which the concrete filling 2a reaches. The embodiment of a story support 2 provided with a centering receptacle 2b is advantageously prefabricated together with the concrete filling 2a. During assembly at the construction site, no fresh concrete need then be processed, thereby reducing the installation time.
Another alternative of a concrete-filled story support 2 (not shown) is built without a floor in the form of a centering receptacle 2b. Due to the missing floor, the concrete 2a is in direct contact with the separating element 10, as can be clearly gleaned from FIG. 1. To achieve a good contact, the story support 2 is first set up empty, without concrete filling. Only when the story support 2 has been set up over the securing mandrel 7 is a filling 2a consisting of fresh, non-shrinking, swellable, fine concrete. The fine concrete sets in the mold defined by the securing mandrel 7 and the separating element 10, and, after it has set, provides for centering and a good transfer of force between the floor structure 3 and the story support 2.
The floor structure 3 visible on
In the finished rooms of the building story, the joining system 4 is concealed inside the floor structure 3. Only the smooth surface of the story support 2 is visible. Non load-bearing wall structures can be secured to the latter.
A concrete filling 25 of the story support 2 is visible underneath the floor 24.
A story support can be sound decoupled at both one of its two ends, or at both ends simultaneously. Sound decoupling in the area of the floor structure 3 is the most effective single measure. This is because structure-borne noise most arises from movements on the floor structure 3, and the structure-borne noise is in this way reduced near where it originates. One optional measure involving sound decoupling at the end of the story support 2 facing the ceiling structure 30 can be selected if a particularly good sound decoupling is desired.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCTDE01/02149 | 6/8/2001 | WO | 00 | 6/23/2003 |
Publishing Document | Publishing Date | Country | Kind |
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WO0196682 | 12/20/2001 | WO | A |
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Number | Date | Country | |
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20040010991 A1 | Jan 2004 | US |