JP5236574B2 - Steel structure floor structure system - Google Patents

Description

  The present invention belongs to the technical field of a floor structure system for a steel building, in particular, a floor structure system in which the vibration disturbance is improved and the comfortability is improved.

In recent years, the floor structure of steel-framed buildings has increased the span and weight of the steel frame, and as a result, there is a high possibility that a floor vibration failure will occur and the habitability will deteriorate. For this reason, countermeasures such as increasing the cross section of the steel beam or incorporating a vibration control device for controlling floor vibration are being implemented as measures against vibration, not from consideration of strength design. As a result, the construction cost is greatly increased.
Therefore, conventionally, in the composite floor beam structure disclosed in, for example, Patent Document 1 below, as a means for integrally constructing the concrete floor slab on the steel beam so as not to increase the frame weight of the floor slab, A flat deck is formed around the edges, and corrugated decks are installed and formed between the flat decks. The concrete slab on the flat deck is thick and the concrete slab on the corrugated deck is thin. A composite floor beam structure has been proposed.
Therefore, the concrete slab on the flat deck formed around the end of the steel beam is built thick and its rigidity and proof stress are increased. However, the concrete slab on the corrugated deck supported by the steel beam is thinly constructed.

  However, in the case of a floor beam structure having a rectangular plan view, it is known that the problem of vibration disturbance is likely to occur at the center of the floor. Therefore, although it is a composite floor beam structure, as in the invention of the above-mentioned Patent Document 1, in the configuration where the concrete slab on the corrugated deck portion supported by the steel beam is thin, the floor vibration disturbance is improved. As a result, the purpose of improving habitability cannot be achieved.

In addition, in the building structure described in Patent Document 2 below, both ends of a precast concrete slab for flooring are installed between steel beams, and a cast-in-place concrete slab is integrated on the steel beam and the precast concrete plate for floors. However, a configuration has been proposed in which a downward taper portion is formed at the end of the precast concrete plate so that the thickness of the concrete slab immediately above the steel beam is large. It is described that the composite effect of the composite beam can be expected with this configuration.
In addition, the composite beam construction method described in Patent Document 3 below is described as building a thick concrete slab on a steel beam to increase the proof strength of the slab as a composite beam.

JP-A-8-312050 JP-A-62-178640 JP 63-142142 A

As described above, it is known that a floor beam structure of a steel building, particularly a floor beam structure having a rectangular (particularly square) plan view, is likely to cause vibration problems at the center of the floor.
Therefore, the object of the present invention is to eliminate the need for an increase in the number of steel frames, an increase in the cross section of the steel frame, etc. It is to provide a floor structure system in which only a portion supported by a steel beam is increased to increase the weight effect, thereby enhancing the vibration damping effect and improving the comfortability.
A further object of the present invention is to lower the construction height of the steel beam at the site that is effective in improving the vibration disturbance of the floor, and conversely, the dimension of the concrete slab at the same site is reduced by the amount of the lowered construction height position. With the construction method that can increase the thickness effect by inflating the lower surface side, increase the weight effect of the concrete slab, increase the vibration damping effect and improve the habitability, and lower the installation height position of the steel beam It is to provide a floor structure system for steel buildings that can be easily implemented according to the level of existing technology.

As a means for solving the above problems, a floor structure system for a steel building according to the invention described in claim 1 is:
In a floor structure system in which a plurality of steel beam 3 is installed between large beams 2 and 2 facing each other of a steel structure building, and a concrete slab 4 is constructed thereon,
Each steel beam 3 has the same size, and only the steel beam 3 ′ at a position where vibration disturbance is likely to occur in the center of the floor is installed with its installation height lowered. The lower surface side of the portion in contact with the steel beam 3 ′ whose height position is lowered is increased by inflating downward by an amount h that the installation position of the steel beam 3 ′ is lowered. And

The invention described in claim 2 is the floor structure system for a steel building according to claim 1,
The bottom surface of the concrete slab at the position where the installation height position of the steel beam 3 ′ is lowered is increased to both sides of the steel beam 3 ′ to an upward tapered shape 4a up to a certain area, and the normal thickness portion 4b. A steel frame 5 serving as a formwork that is in contact with the lower surface 4b of the normal thickness portion of the concrete slab 4 is installed on both side edges of the upper flange 3a of the steel beam 3 '. It is characterized by being thickened.
The invention described in claim 3 is the floor structure system for a steel building according to claim 1 or 2,
The large beam 2 of the steel structure has a substantially square arrangement in plan view. Among the steel beam 3 that is installed at a constant pitch between the large beams 2 and 2 that face each other in parallel, a vibration failure occurs in the center of the floor. Only the steel beam 3 ′ at an easy position is installed with its installation height lowered, and the concrete slab 4 is expanded by expanding the lower surface of the part in contact with the steel beam 3 ′ with the installation height lowered. It has a thick structure.

In the floor structure system for a steel structure building according to the present invention, only the steel beam 3 ′ at a position where vibration disturbance is likely to occur in the center of the floor is installed with its installation height lowered, and the installation position is set in the concrete slab 4. Since the lower surface side of the portion in contact with the lowered steel beam 3 ′ is inflated downward by the dimension h in which the installation height position of the steel beam 3 ′ is lowered, the thickness is increased. The rigidity of this part increases and the weight increases. Therefore, for example, as clearly shown in the comparison between the evaluation point P of the present invention shown in FIG. 4 and the evaluation point Q of the prior art, the point P is shifted to the left from the point Q, the frequency decreases, and the period becomes longer. It is clear that the comfort is improved.
In the construction of the floor structure system for a steel building according to the present invention, each steel beam 3 may have the same size in construction, and is installed at a constant pitch between the opposed beams 2 and 2. Among the steel beam 3, the installation height position of the steel beam 3 ′ at a position where vibration disturbance is likely to occur in the center of the floor is lowered and correspondingly, the steel beam 3 is included in the concrete slab 4. Since the lower surface side of the part in contact with 'can be expanded by increasing the height of the steel beam 3' by the height h of the installation height, the construction method must be changed significantly. Because there is no need to increase the number of steel frames or the cross section of the steel frame, it is not necessary to use a separate vibration control device, etc., and it can be carried out simply by lowering the construction height position of the specific steel beam 3 ′. There will be no cost and technical burden, and construction technology will be exceptional. Therefore, it can be implemented easily and inexpensively at the level of existing technology.

It is the top view which showed the example of steel frame arrangement | positioning in the floor structure system of this invention. It is sectional drawing to which the II-II line arrow of FIG. 1 expanded. It is sectional drawing which shows a different Example in the form cut | disconnected along the III-III arrow of FIG. It is a performance figure which shows the result of the habitability evaluation test regarding the floor structure system of this invention.

The present invention is applied to a floor structure system in which a plurality of small steel beams 3 are installed between large beams 2 and 2 facing each other of a steel building and concrete slabs 4 are installed thereon.
Each steel beam 3 is all the same size, and only the steel beam 3 'at a position where vibration disturbance is likely to occur in the center of the floor is installed with its installation height lowered. On the other hand, in the concrete slab 4, the lower surface side of the portion in contact with the steel beam 3 ′ having the lowered installation height position is inflated downward by the dimension h in which the installation height position of the steel beam 3 ′ has been lowered. Implement with a thickened configuration.

  FIG. 1 shows an example of a planar arrangement of steel frames constituting a floor structure system for a steel building according to the present invention. That is, the steel beam 2 joined to the steel column 1 located at the four corners is arranged in a substantially square shape in plan view. Then, a plurality of (three in FIG. 1) steel beam 3 is installed between the steel beams 2 and 2 that face each other substantially parallel to each other. As shown in FIG. A concrete slab 4 is constructed and supported. The configuration of the basic floor structure described above is not different from the existing floor structure system of a steel building.

The feature of the present invention is that, based on the basic configuration described above, first, each steel beam 3 is constructed with the same size as shown in FIG. However, only the steel beam 3 ′ at the position where vibration disturbance is likely to occur in the center of the floor (hereinafter, distinguished from other steel beam 3 by reference numeral 3 ′), the installation height position is shown in the embodiment of FIG. Then, it is installed by lowering the h dimension.
The size of the h dimension is determined as a design matter. The floor shape and size of the floor to be implemented, the ratio of vertical and horizontal dimensions, the size of the steel frame used, the number and arrangement pitch of the steel beam 3 and the basic thickness and mass of the concrete slab 4 etc. This is because it is a matter that should be properly designed and determined based on various specifications.
In addition, as a construction method in which only the specific steel beam 3 ′ described above is installed with its erection height position lowered by h dimension, the steel beam 2 that is the joining partner is usually due to the joining partner of the beam. Therefore, it does not require special processing or a work for adding a joining member or the like. Of course, it is assumed that it is necessary to add processing or joining members as necessary.

On the other hand, regarding the construction of the concrete slab 4, construction is performed with a normal thickness basically based on the existing technology. However, only the portion in contact with the steel beam 3 ′ whose construction height position is lowered is the dimension h in which the construction height position of the steel beam 3 ′ is lowered as shown in the center position of FIG. Only work with a thickened structure by inflating the lower surface side downward.
As a construction method to partially thicken the concrete slab 4, for example, as shown on the lower surface of the concrete slab in contact with the steel beam 3 'located in the center of Fig. 2, design both sides of the steel beam 3'. A means for increasing the thickness by a construction in which the up to a predetermined region is applied to the upward tapered shape 4a and connected to the lower surface 4b of the normal thickness portion is suitably implemented.
Of course, the shape of the bottom surface of the concrete slab 4 that is inflated and thickened only at the part that is in contact with the steel beam 3 ′ whose height has been lowered can be increased when designing from the viewpoint of vibration countermeasures. It is a matter determined appropriately so as to achieve the purpose of increasing the weight and increasing the weight to increase the vibration damping effect.

  As a different embodiment, the lower surface of the concrete slab 4 shown on the left side of FIG. 3 is formed on the left and right edges of the upper flange 3a of the steel beam 3 ′ installed with the installation height position lowered by h. An angle-shaped (L-shaped cross-section) formwork / steel frame 5 having a height that is in contact with the lower surface 4b of the normal thickness portion of the slab 4 is placed in a symmetrical arrangement, and concrete is placed inside thereof. Thus, the thickness is increased to a substantially rectangular shape 4c.

Next, FIG. 4 shows the result of evaluating the habitability of the floor by the so-called simulation of the floor structure system of the present invention configured as shown in FIG.
As shown in FIG. 2, the height of the steel beam 3 'is lowered by an amount corresponding to the dimension h, and the lower surface side of the concrete slab 4 in contact with the steel beam 3' is expanded downward to increase the thickness. In this case, the weight is inevitably increased and the rigidity is increased, so that it is expected that a floor vibration damping effect can be obtained.
In FIG. 4, the vertical axis represents acceleration amplitude (cm / sec ² ), and the horizontal axis represents frequency (Hz). The central thick line R is a boundary index indicating the pros and cons of habitability. The point Q evaluated for the configuration of the conventional technique that does not lower the erection height position of the steel beam 3 is located in the NG area where the evaluation above the thick line R indicating the boundary index indicating the livability is lower.
However, the evaluation point P in the case of the embodiment of the present invention (FIG. 2) is located in an OK area where the evaluation below the thick line R of the boundary index is good. Moreover, it is shown that the cycle is further to the left than the evaluation point Q of the existing technology and the position is excellent in the comfortability with a long period.

  However, the present invention is not limited to the embodiment described above. For example, in the embodiment shown in the figure, only one steel beam 3 ′ located at the center of the floor among the three steel beams 3 is installed with its installation height lowered by h dimension. Although the bottom surface of the concrete slab in contact with the beam 3 'is locally expanded downward to increase the thickness, the floor shape has become larger and the number of steel beams 3 has increased dramatically. If the floor shape of the floor is a rectangle that is long in one direction, depending on the state of occurrence of the vibration disturbance, for example, the installation height position of the plurality of steel beam 3 'located in the center is determined. A configuration in which the thickness is increased by lowering and inflating the lower surface of the concrete slab at the portion in contact with each steel beam 3 ′ downward is also implemented. As described above, the present invention can be applied to various embodiments within the scope of design changes and applications that are usually performed by those skilled in the art.

2 Large beam 3 Steel beam 3 'Small beam 4 Construction slab 5 Steel frame for formwork h Dimension of steel beam is lowered

Claims (3)

In a floor structure system in which a plurality of steel beams are installed between large beams facing each other in a steel structure, and concrete slabs are installed on top of them.
Each steel beam is the same size, and only the steel beam at the position where vibration disturbance is likely to occur in the center of the floor is installed with its installation height lowered, while the installation height position is set on the concrete slab. The floor of a steel building is characterized in that the lower surface side of the part in contact with the lowered steel beam is inflated downward by an amount corresponding to the lowered installation height position of the steel beam to increase the thickness. Structural system.   The bottom surface of the concrete slab, where the height of the steel beam is lowered, is connected to the normal thickness part by increasing the thickness of both sides of the steel beam to an upward tapered shape up to a certain area. The both sides of the upper flange of the small beam are thickened in a substantially rectangular shape by installing a formwork combined steel frame with a height in contact with the lower surface of the normal thickness portion of the concrete slab. The floor structure system of a steel structure described in 1.   The steel beams in the steel building are almost square in plan view, and the steel beams in the position where vibration disturbances in the center of the floor are likely to occur among the steel beams built at a constant pitch between the parallel beams facing each other in parallel. Only the beam is installed with its installation height lowered, and the concrete slab has a structure in which the lower surface of the part in contact with the steel beam with the installation height lowered is inflated downward to increase the thickness. The floor structure system for a steel structure building according to claim 1 or 2.

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