Floor structure including plate-shaped supporting portion

A floor structure includes a plurality of structural metal components that each have: a plate-shaped supporting portion that is laid either perpendicular or oblique to an installation surface; a plate-shaped top flange that extends from a top end portion of the supporting portion in parallel with the installation surface; a plate-shaped bottom flange that extends from a bottom end portion of the supporting portion in parallel with the installation surface and in the opposite direction from the top flange, wherein the structural metal components are laid on a flat surface in parallel with each other such that the top flange of one of the mutually adjacent structural metal components covers the bottom flange of the other of the mutually adjacent structural metal material.

TECHNICAL FIELD

The present invention relates to a floor structure.

Priority is claimed on Japanese Patent Application No. 2007-000087, filed Jan. 4, 2007, and Japanese Patent Application No. 2007-319914, filed Dec. 11, 2007, the contents of which are incorporated herein by reference.

BACKGROUND ART OF THE INVENTION

When the structural framework of an erected construction such as a building or house is constructed using a steel structure (S structure), a steel reinforced concrete structure (RC structure), or a steel framed reinforced concrete structure (SRC structure), normally, the floor structure of the erected construction is formed by a concrete floor structure or by a composite structure which combines steel deck plates and an RC structure (referred to below as an RC floor structure), however, building a steel-construction floor that is formed solely from steel is also possible with current construction technology.

Prior art relating to the aforementioned floor structures is disclosed, for example, in Patent documents 1 to 5 shown below. Specifically, a floor structure that uses folded plate-shaped steel floor panels is described in Patent documents 1 and 2. A method of constructing a floor using deck plates is described in Patent document 3. This construction method is a technology for an RC floor structure in which a plurality of beam materials are assembled as a base, and after this assembled unit has been put in position, concrete is laid over the deck plates. A floor structure in which a plurality of box-shaped steel materials are arranged in parallel is described in Patent document 4. Technology for an RC floor structure in which a plurality of folded deck plates are arranged in parallel and concrete is then laid over the deck plates is described in Patent document 5.Patent document 1: Japanese Unexamined Patent Application, First Publication No. 2003-119946Patent document 2: Japanese Patent No. 3781674Patent document 3: Japanese Unexamined Patent Application, First Publication No. H11-293834Patent document 4: Japanese Unexamined Patent Application, First Publication No. 2003-293017Patent document 5: Japanese Unexamined Patent Application, First Publication No. 2005-320722

DETAILED DESCRIPTION OF THE INVENTION

Problems to be Solved by the Invention

It has, however, been more common to use an RC floor structure rather than a steel structure for the floor structure of an erected construction. The reason for this is that, in a steel floor structure, because noise generated on the floor above is more easily transmitted to the floor below compared with an RC floor structure in which concrete is laid in addition to steel, vibration and noise are easily generated thus creating the problem of impact noise.

Moreover, when a steel floor structure is being built, in a floor structure in which, for example, the box-shaped steel material described in the aforementioned Patent document 4 are used, because the box-shaped steel materials are extremely bulky, an RC floor structure is advantageous from the standpoints of ease of construction and transporting. However, in the aforementioned Patent documents 1 and 2, in a floor structure in which steel floor panels are used, although devices are employed to suppress vibration and noise, the problem has been that no examination has been made of the costs involved in manufacturing such floor structures and in transporting the steel material used for this manufacturing.

The present invention was conceived in view of the above described circumstances, and it is an object thereof to provide a new and improved floor structure that makes it possible to reduce the costs involved in both manufacturing the floor structure and in transporting the steel materials used in the manufacturing thereof.

Means for Solving the Problem

In order to solve the above described problems, the present invention employs the following. Namely, the floor structure of the present invention includes a plurality of structural metal components that each have: a plate-shaped supporting portion that is laid either perpendicular or oblique to an installation surface; a plate-shaped top flange that extends from a top end portion of the supporting portion in parallel with the installation surface; a plate-shaped bottom flange that extends from a bottom end portion of the supporting portion in parallel with the installation surface and in the opposite direction from the top flange, wherein the structural metal components are laid on a flat surface in parallel with each other such that the top flange of one of the mutually adjacent structural metal components covers the bottom flange of the other of the mutually adjacent structural metal material.

According to the above described floor structure, as a result of a structural metal component being laid as the floor of an erected construction, a supporting portion that is laid either perpendicular or oblique to an installation surface transmits force from a top flange to a bottom flange and the top flange supports a load on the floor, while the bottom flange supports the load and also supports the structural metal component itself. Here, the structural metal component can be manufactured using less material than is used for box-shaped steel. Moreover, because a plurality of other structural metal components can be stacked on top of one structural metal component, it is possible to reduce the space taken up by the stacked structural metal components. Furthermore, when the structural metal components are being transported, it is possible to transport a large number of the structural metal components in a single load. As a result, it is possible to reduce the costs involved in both manufacturing a floor structure and in transporting the steel materials used in the manufacturing thereof.

It may be arranged such that at least one of the supporting portion, the top flange, and the bottom flange is provided with a rib that protrudes from the surface thereof.

In this case, it is possible to increase the out-of-plane flexural rigidity of the supporting portion, the top flange, and the bottom flange of a floor structure, and improve localized buckling strength. Accordingly, it is possible to lighten the weight of the structural metal components which, in turn, makes it possible to reduce manufacturing costs and increase profitability. Note that the rib may be formed by bending the structural metal component itself, or may be formed by attaching a reinforcing component by means of welding or the like.

It may be arranged such that an angle formed between the supporting portion and the top flange or bottom flange is between 30° and 150°.

In this case, because the angle of the supporting portion is in a range between 30° and 150°, structural properties (i.e., the geometrical moment of inertia (I/A) per unit surface area) either equivalent to or superior to box-shaped steel of the same height can be provided, which results in a floor structure having excellent structural properties being obtained.

It may be arranged such that a distal end portion of the top flange of one of the mutually adjacent structural metal components is connected to a top end portion of the supporting portion of the other of the mutually adjacent structural metal components.

In this case, in a floor structure in which a plurality of structural metal components are laid in parallel, it is possible to form a continuous top surface on the floor structure.

It may be arranged such that the supporting portion is provided with a connection surface that is formed on a top end portion thereof at a lower position than the top surface of the top flange; and the distal end portion of the top flange of one of the mutually adjacent structural metal components is connected to the connection surface of the other of the mutually adjacent structural metal components.

In this case, it is possible to arrange the top surfaces of the top flanges of adjacent structural metal components on the same plane.

It may be arranged such that the top flange is provided with a thin portion that is formed at the distal end portion thereof; and the thin portion of one of the mutually adjacent structural metal components is connected to the connection surface of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the top surfaces of the top flanges of adjacent structural metal components on the same plane.

It may be arranged such that the supporting portion is provided with a fitting portion that is formed on a top end portion thereof; and the distal end portion of the top flange of one of the mutually adjacent structural metal components is fitted to the fitting portion of the other of the mutually adjacent structural metal components.

In this case, it is possible to easily connect one structural metal component to an adjacent structural metal component, which results in an improvement in workability. It also becomes difficult for the structural metal components to move, and thereby it is possible to increase the in-plane shear rigidity of the floor structure.

It may be arranged such that the supporting portion is provided at the top end portion thereof with a protruding portion that protrudes in the extending direction of the bottom flange; the top flange is provided at the distal end portion thereof with a step portion having a surface that is lower than the top surface of the top flange; and the step portion of one of the mutually adjacent structural metal components is connected to the protruding portion of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the top surfaces of the top flanges of adjacent structural metal components on the same plane.

It may be arranged such that the top flange is provided on the distal end portion thereof with a connection protruding portion that extends in a longitudinal direction; the supporting portion is provided either in the top end portion thereof and/or in the top flange adjacent to the top end portion thereof with a connection aperture portion that extends in the longitudinal direction; and the connection protruding portion in one of the mutually adjacent structural metal components is inserted into the connection aperture portion in the other of the mutually adjacent structural metal components.

In this case, because joins between the top flanges of mutually adjacent structural metal components are further strengthened, it is possible to increase the in-plane shear rigidity of the floor.

It may be arranged such that a plurality of the connection protruding portions and the connection aperture portions are provided separately from each other in the longitudinal direction.

In this case, it is possible to efficiently join together the top flanges of mutually adjacent structural metal components.

It may be arranged such that a distal end portion of the bottom flange of one of the mutually adjacent structural metal components is connected to a bottom end portion of the supporting portion of the other of the mutually adjacent structural metal components.

In this case, in a floor structure in which a plurality of structural metal components are laid in parallel, it is possible to form a continuous bottom surface on the floor structure.

It may be arranged such that the supporting portion is provided with a connection surface that is formed on a bottom end portion thereof at a higher position than the bottom surface of the bottom flange; and the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is connected to the connection surface of the other of the mutually adjacent structural metal components.

In this case, it is possible to arrange the bottom surfaces of the bottom flanges of adjacent structural metal components on the same plane.

It may be arranged such that the bottom flange is provided with a thin portion that is formed at the distal end portion thereof; and the thin portion of one of the mutually adjacent structural metal components is connected to the connection surface of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the bottom surfaces of the bottom flanges of adjacent structural metal components on the same plane.

It may be arranged such that the supporting portion is provided with a fitting portion that is formed on a bottom end portion thereof, and the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is fitted to the fitting portion of the other of the mutually adjacent structural metal components.

In this case, it is possible to easily connect one structural metal component to an adjacent structural metal component, which results in an improvement in workability. It also becomes difficult for the structural metal components to move, and thereby it is possible to increase the in-plane shear rigidity of the floor structure.

It may be arranged such that the supporting portion is provided at the bottom end portion thereof with a protruding portion that protrudes in the direction in which the top flange extends; the bottom flange is provided at the distal end portion thereof with a step portion having a surface that is higher than the bottom surface of the bottom flange; and the step portion at the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is connected to the protruding portion of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the bottom surfaces of the bottom flanges of adjacent structural metal components on the same plane.

It may be arranged such that the bottom flange is provided on the distal end portion thereof with a connection protruding portion that extends in a longitudinal direction; the supporting portion is provided either in the bottom end portion thereof and/or in the bottom flange adjacent to the bottom end portion thereof with a connection aperture portion that extends in the longitudinal direction; and the connection protruding portion in one of the mutually adjacent structural metal components is inserted into the connection aperture portion in the other of the mutually adjacent structural metal components.

In this case, because joins between the bottom flanges of mutually adjacent structural metal components are further strengthened, it is possible to increase the in-plane shear rigidity of the floor.

It may be arranged such that a plurality of the connection protruding portions and the connection aperture portions are provided separately from each other in the longitudinal direction.

In this case, it is possible to efficiently join together the bottom flanges of mutually adjacent structural metal components.

It may be arranged such that the distal end portion of the top flange of one of the mutually adjacent structural metal components is connected to the top end portion of the supporting portion of the other of the mutually adjacent structural metal components; and the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is connected to the bottom end portion of the supporting portion of the other of the mutually adjacent structural metal components.

In this case, in a floor structure in which a plurality of structural metal components are laid in parallel, it is possible to form a continuous top surface and bottom surface on the floor structure.

It may be arranged such that the supporting portion is provided with a first connection surface that is formed on a top end portion thereof at a lower position than the top surface of the top flange; the distal end portion of the top flange of one of the mutually adjacent structural metal components is connected to the first connection surface of the other of the mutually adjacent structural metal components; the supporting portion is provided with a second connection surface that is formed on a bottom end portion thereof at a higher position than the bottom surface of the bottom flange; and the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is connected to the second connection surface of the other of the mutually adjacent structural metal components.

In this case, it is possible to arrange the top surfaces of the top flanges and the bottom surfaces of the bottom flanges of adjacent structural metal components on the same planes.

It may be arranged such that the top flange is provided with a first thin portion that is formed at the distal end portion thereof; the first thin portion of one of the mutually adjacent structural metal components is connected to the first connection surface of the other of the mutually adjacent structural metal components; the bottom flange is provided with a second thin portion that is formed at the distal end portion thereof; and the second thin portion of one of the mutually adjacent structural metal components is connected to the second connection surface of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the top surfaces of the top flanges and the bottom surfaces of the bottom flanges of adjacent structural metal components on the same planes.

It may be arranged such that the supporting portion is provided with a first fitting portion that is formed on a top end portion thereof; the distal end portion of the top flange of one of the mutually adjacent structural metal components is fitted to the first fitting portion of the other of the mutually adjacent structural metal components; the supporting portion is provided with a second fitting portion that is formed on a bottom end portion thereof; and the distal end portion of the bottom flange of one of the mutually adjacent structural metal components is fitted to the second fitting portion of the other of the mutually adjacent structural metal components.

In this case, it is possible to easily connect one structural metal component to an adjacent structural metal component, which results in an improvement in workability. It also becomes difficult for the structural metal components to move, and thereby it is possible to increase the in-plane shear rigidity of the floor structure.

It may be arranged such that the supporting portion is provided at the top end portion thereof with a first protruding portion that protrudes in the direction in which the bottom flange extends; the top flange is provided at the distal end portion thereof with a first step portion having a surface that is lower than the top surface of the top flange; the first step portion of one of the mutually adjacent structural metal components is connected to the first protruding portion of the other of the mutually adjacent structural metal components; the supporting portion is provided at the bottom end portion thereof with a second protruding portion that protrudes in the direction in which the top flange extends; the bottom flange is provided at the distal end portion thereof with a second step portion having a surface that is higher than the bottom surface of the bottom flange; and the second step portion of one of the mutually adjacent structural metal components is connected to the second protruding portion of the other of the mutually adjacent structural metal components.

In this case, positioning is made easier when the structural metal components are being laid. In addition, it is possible to arrange the top surfaces of the top flanges and the bottom surfaces of the bottom flanges of adjacent structural metal components on the same planes.

It may be arranged such that the top flange is provided on the distal end portion thereof with a first connection protruding portion that extends in a longitudinal direction; the supporting portion is provided either in the top end portion thereof and/or in the top flange adjacent to the top end portion thereof with a first connection aperture portion that extends in the longitudinal direction; the first connection protruding portion in one of the mutually adjacent structural metal components is inserted into the first connection aperture portion in the other of the mutually adjacent structural metal components; the bottom flange is provided on the distal end portion thereof with a second connection protruding portion that extends in a longitudinal direction; the supporting portion is provided either in the bottom end portion thereof and/or in the bottom flange adjacent to the bottom end portion thereof with a second connection aperture portion that extends in the longitudinal direction; and the second connection protruding portion in one of the mutually adjacent structural metal components is inserted into the second connection aperture portion in the other of the mutually adjacent structural metal components.

In this case, because joins between the top flanges of mutually adjacent structural metal components and joins between the bottom flanges of mutually adjacent structural metal components are further strengthened, it is possible to increase the in-plane shear rigidity of the floor.

It may be arranged such that a plurality of the first connection protruding portions, the first connection aperture portions, the second connection protruding portions, and the second connection aperture portions are provided separately from each other in the longitudinal direction.

In this case, it is possible to efficiently join together the top flanges of mutually adjacent structural metal components and the bottom flanges of mutually adjacent structural metal components.

It may be arranged such that the mutually adjacent structural metal components are fixed together by means of semi-finished bolts, high strength bolts, drill screws, rivets, welding, or bonding.

In this case, it becomes difficult for the structural metal components to move, and thereby it is possible to increase the in-plane shear rigidity of the floor structure.

It may be arranged such that at least one of the structural metal components is a floor beam structural metal component in which a bulging portion is formed as a result of the bottom flange bulging downwards from a bottom end portion of the supporting portion.

In this case, the floor beam structural steel materials protrude below the bottom flanges of the structural metal components, and have a U-shaped cross section. Because of this, when they are laid as at least a portion of a floor structure, they function as beam components for the floor structure. Accordingly, in an erected construction which uses this type of floor beam structural metal components, it is possible to omit joists such as binding joists, and thereby achieve an improvement in workability and profitability.

It may be arranged such that at least one of a noise-proofing material, a weight, a mechanical damper, and a granular material is provided between the bottom flange and the top flange.

In this case, it is possible to prevent noise and vibration being transmitted from a floor above to a floor below. Moreover, it is also possible to install the structural metal component that is to be laid next in such a manner that it covers the bottom flange and the noise-proofing material. As a result, it is possible to reduce both the time and cost of this task.

It may be arranged such that the noise-proofing material is concrete.

In this case, in addition to it being possible to prevent noise and vibration being transmitted from a floor above to a floor below, it is also possible to increase the rigidity of a floor structure. As a result, the height of the floor structure can be lowered. Note that the concrete is positioned by suspending hardened concrete lumps from the top flange, or by pouring concrete that is still in liquid form into a space between the top flange and the bottom flange. In particular, when a noise-proofing material is formed by pouring liquid concrete, superior rigidity can be imparted to the floor structure.

It may be arranged such that at least one of electric cables, equipment piping, and ducts are provided between the bottom flange and the top flange.

In this case, it is possible to install at least one of electric cables, equipment piping, and ducts to be provided between the bottom flange and the top flange.

It may be arranged such that at least one plate material selected from a concrete panel, an aerated lightweight concrete panel (i.e., an ALC panel), a wooden board, slate, a ceramic board, a glass wool board, a plaster board, a metal panel, and a ceramic-based siding board is integrally fixed to the structural metal components on the top surface of the top flange and/or the bottom surface of the bottom flange.

In this case, the number of on-site tasks to be performed can be reduced so that, as a result, it is possible to improve workability.

It may be arranged such that the bottom flange and the supporting portion are provided with a notch portion at an end portion in the longitudinal direction thereof; and the structural metal component is connected to a top surface of the structural framework of an erected construction via the notch portion.

In this case, it is possible to limit the height between the top surface of the structural framework of an erected construction and the top surface of the structural metal components.

Advantageous Effects of the Invention

According to the present invention, it is possible to reduce the costs involved in both manufacturing a floor structure and in transporting the steel materials used in the manufacturing thereof.

DESCRIPTION OF THE REFERENCE SYMBOLS

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Note that in the present specification and drawings, components elements that have essentially the same functional structure have the same symbols, and any duplicated description thereof is omitted.

First Embodiment

Firstly, a structural steel material and floor structure according to a first embodiment of the present invention will be described.FIGS. 1A and 1Bare side views showing the structural steel material and floor structure according to the present embodiment.FIGS. 2A to 2Care side views showing the structural steel material and floor structure according to the present embodiment.FIG. 3is a perspective view showing the structural steel material and floor structure according to the present embodiment.

As is shown inFIGS. 1B,2C, and3, the floor structure according to the present embodiment is formed by arranging a plurality of structural steel materials100in parallel. The floor structure is used for the structural framework of an erected construction, for example, of a building such as a commercial building or house. A top flange104of any one structural steel material100is placed so as to cover a top surface of a bottom flange106of another structural steel material100that is placed adjacently thereto.

As is shown inFIGS. 1A and 2A, the structural steel materials100according to the present embodiment are provided with a web102, a top flange104, and a bottom flange106. Note that inFIGS. 1A and 1B, a case is shown in which the plate thicknesses of the webs102and the top flanges104and bottom flanges106are the same. In contrast, inFIGS. 2A to 2C, a case is shown in which the plate thicknesses of the top flanges104and bottom flanges106are thicker than the plate thickness of the webs102. Here, the webs102are an example of a supporting portion.

The structural steel materials100are manufactured, for example, from steel, and are manufactured by hot roll molding or cold roll molding, press molding, extrusion molding, or draw molding or the like. Accordingly, the structural steel materials100can be manufactured easily and manufacturing costs can be reduced. The structural steel materials100are an example of a structural metal component. Note that in the present embodiment, a description is given of an example in which the structural metal components are manufactured from steel, however, the present invention is not limited to this example. For example, the structural metal components may also be metal components formed from an aluminum alloy or titanium alloy or the like.

As is shown inFIG. 3, the webs102are elongated steel plates that are positioned perpendicularly to the installation surfaces when the structural steel materials100are arranged as the floor of an erected construction. The top flanges104extend from top end portions102aof the webs102in parallel with the installation surfaces. The bottom flanges106extend from bottom end portions102bof the webs102in parallel with the installation surfaces, and in the opposite direction from the top flanges104.

As is shown inFIG. 3, the top flanges104are elongated steel plates. When the structural steel materials100are laid as the floor of an erected construction, the top flanges104extend from the top end portions102aof the webs102in parallel with the installation surfaces so as to form horizontal top surfaces. Free end sides of the top flanges104form end portions104athat are free relative to the top end portions102aof the fixed webs102. The end portions104aare in contact with the top end portion102aof the web102of another structural steel material100that is placed adjacent thereto. A top surface of the floor structure is formed with no gaps in it by laying a plurality of structural steel materials100in this manner.

As is shown inFIG. 3, the bottom flanges106are also elongated steel plates. When the structural steel materials100are laid as the floor of an erected construction, the bottom flanges106extend in the opposite direction to the top flanges104from the bottom end portions102bof the webs102in parallel with the top flanges104so as to form horizontal bottom surfaces. Free end sides of the bottom flanges106form end portions106athat are free relative to the bottom end portions102bof the fixed webs102. The bottom ends106aare in contact with the top end portion102aof the web102of another structural steel material100that is placed adjacent thereto. A top surface of the floor structure is formed with no gaps in it by arranging a plurality of structural steel materials100in this manner.

As is shown inFIG. 2B, the structural steel materials100may be stacked by stacking one structural steel material100on top of another structural steel material100. A plurality of structural steel materials1100may be stacked on top of each other provided that they do not become deformed and provided that there is no deterioration in their structural properties. Therefore, according to the present embodiment, when the structural steel materials are being transported, a large number of structural steel materials100can be loaded onto the loading bed of a truck, for example, without occupying any more space than is necessary (i.e., is space saving). Namely, it is possible to increase the quantity that can be transported in a single load. As a result, transporting costs can be reduced.

Next, a description will be given of an end portion steel material that is used as an end portion of a floor structure with reference toFIGS. 4A through 4D.FIGS. 4A through 4Dare side views showing the structural steel materials, end portion steel materials and the floor structure according to the present embodiment.

When a plurality of just the above described structural steel materials100have been laid in parallel with each other, the top flanges104and the bottom flanges106are not formed on end portions of the floor structure, and here the structure has no top surface or no bottom surface. Accordingly, end portion steel materials are laid in order to close off the floor structure. In the same way as the structural steel materials100, the end portion steel materials are manufactured from, for example, steel, and are manufactured by roll molding or press molding or the like. The shape of the end portion steel materials is not restricted provided that it allows the end portions of the floor structure to be closed. A specific example thereof is described below.

As is shown inFIGS. 3 and 4A, an end portion steel material110has an L-shaped cross section and is formed, for example, by a web112and a flange114. The web112is an elongated steel plate, and is positioned perpendicularly to an installation surface when the structural steel materials100are laid as the floor of an erected construction. The flange114is an elongated steel plate and extends from an end portion of the web112in a perpendicular direction relative to the web112. The end portion steel material110is positioned such that, in the floor structure in which the plurality of structural steel materials are laid in parallel with each other, on the side thereof where a top flange104forms an end portion, the flange114of the end portion steel material110is placed horizontally as the bottom surface of the floor structure, and such that the flange114is covered by the top flange104of the structural steel material100. In contrast, on the side where a bottom flange106forms an end portion, the flange114of the end portion steel material110is placed horizontally as the top surface of the floor structure, and such that it covers the bottom flange106of the structural steel material100.

Moreover, as is shown inFIG. 4B, an end portion steel material120is formed by a web122, a first flange124, an end component126, and a second flange128. The web122is an elongated steel plate, and is positioned perpendicularly when the structural steel materials100are laid as the floor of an erected construction. The first flange124is an elongated steel material and extends in one direction from an end portion of the web122, and is placed horizontally relative to the installation surface. The end component126is an elongated steel material, and is positioned extending from one end portion of the first flange124in parallel with the web122. The end component126has the same height, for example, as the web122. The second flange128is an elongated steel material and extends in the opposite direction to the first flange124from another end portion of the web122, and is placed horizontally relative to the installation surface. A cross section of the web122, the first flange124, and the end component126form a flat-end U shape. By employing this structure, the end portion steel material120has the function of joining with the beams of the structural framework of the erected construction that support the floor structure.

In the same way as for the above described end portion steel material110, the end portion steel material120is also positioned such that, in the portion of the floor structure where a top flange104of a structural steel material forms an end portion, the second flange128of the end portion steel material120is placed horizontally as the bottom surface of the floor structure, and such that the second flange128is covered by the top flange104of the structural steel material100. In contrast, in the portion where a bottom flange106forms an end portion, the second flange128of the end portion steel material120is placed horizontally as the top surface of the floor structure, and such that it covers the bottom flange106of the structural steel material100.

Moreover, as is shown inFIG. 4C, an end portion steel material130may also be formed from shaped steel132having a box-shaped cross-sectional configuration, and steel plates134and136having a flat plate shape. The height of the shaped steel132when it is placed in position as a structural component of the floor structure is substantially the same as the internal dimension between the top flange104and the bottom flange106of the structural steel material100. The steel plates134and136are elongated steel materials, and the steel plate134has a narrower width than the steel plate136. The shaped steel132, the steel plate134, and the steel plate136may be formed into a single unit by welding or the like.

The end portion steel materials130are arranged such that, in that portion of a floor structure in which a plurality of structural steel materials100have been arranged in parallel with each other where the top flange104forms an end portion, the steel plate136is placed horizontally as the bottom surface of the floor structure, and the shaped steel132is placed above the steel plate136as the end portion of the floor structure. In addition, the steel plate134is positioned so as to be in contact with the top flange104of a structural steel material100above the shaped steel132. In contrast, in that portion where the bottom flange106of a structural steel material100forms an end portion, the steel plate134is placed horizontally as the bottom surface of the floor structure, and the shaped steel132is placed above the steel plate134as the end portion of the floor structure. In addition, the steel plate136is positioned so as to be in contact with the top flange104of a structural steel material100above the shaped steel132.

Note that a description has been given of a case in which the above described end portion steel materials130are provided with a narrow-width steel plate134, however, the present invention is not limited to this structure. It is also possible to not provide the steel plate134, and instead to place the shaped steel132between the steel plate136and the top flange104or the bottom flange106of the structural steel materials100.

Furthermore, as is shown inFIG. 4D, it is also possible for an end portion steel material140to be formed that uses H-shaped steel142which has an H-shaped cross section as a structural component instead of the shaped steel132of the above described end portion steel materials130. General H-shaped steel can be used for the H-shaped steel142, and this H-shaped steel is formed by a web142, and two mutually parallel flanges146. The structure of the steel plates134and136and also the placement of the H-shaped steel142are the same as for the above described end portion steel material130, therefore, a detailed description thereof is omitted.

Next, the structural properties of the structural steel material100according to the present embodiment will be described.FIG. 5is a table showing characteristics of the structural steel material100according to the present embodiment and of shaped steel according to the conventional technology.

Here, the shaped steel of the conventional technology that is used for a comparison is the box-shaped steel material disclosed in Patent document 4. A plurality of these box-shaped steel materials10are arranged in parallel so as to form a floor structure. The box-shaped steel materials10of this comparison have both a width and height of 200 mm, and a thickness of 4.5 mm. The structural steel material100according to the present embodiment which is shown in column (b) inFIG. 5has the following dimensions. Namely, the height of the web102is 200 mm, the lengths of the top flange104and the bottom flange106are 200 mm, and the thickness is 4.5 mm. The structural steel material100according to the present embodiment which is shown in column (c) inFIG. 5has the following dimensions. Namely, the height of the web102is 200 mm, the lengths of the top flange104and the bottom flange106are 295.5 mm, and the thickness is 4.5 mm.

The lengths of the web102, the top flange104and the bottom flange106of the structural steel material100according to the present embodiment shown in column (b) inFIG. 5are the same as the width and height of the box-shaped steel materials10used for this comparison. At this time, the structural steel materials100of the present embodiment have a cross-sectional area A which is substantially ¾ths that of the box-shaped steel materials10, enabling a reduction to be achieved in the quantity of steel material that is used. Moreover, the flexural rigidity (a geometrical moment of inertia I) per unit surface area I/A thereof is 1.16 times the flexural rigidity (a geometrical moment of inertia I) per unit surface area I/A of the box-shaped steel materials10.

Furthermore, the length of the web102of the structural steel material100according to the present embodiment shown in column (c) inFIG. 5is the same as the height of the box-shaped steel materials10. In addition, the lengths of the top flange104and the bottom flange106are set such that the structural steel materials100of the present embodiment have a cross-sectional area which is the same as that of the box-shaped steel materials10. At this time, because the two cross-sectional areas are the same, the quantity of steel that is used is the same, however, the flexural rigidity (the geometrical moment of inertia I) per unit surface area I/A of the structural steel materials100is 1.267 times the flexural rigidity (the geometrical moment of inertia I) per unit surface area I/A of the box-shaped steel materials10.

As a result of the above, according to the present embodiment, compared with a floor structure in which conventional box-shaped steel materials10are laid, a floor structure in which a plurality of structural steel materials100are laid has improved structural properties and is a more lightweight structure.

Next, a description will be given of an optimum width L for the top flange104and bottom flange106according to the present embodiment with reference toFIG. 6.FIG. 6is a graph showing a relationship between structural properties relating to flexural rigidity and the flange width and web height of the structural steel material100according to the present embodiment.

The range of the flange width L is fixed in consideration of bending of the flange, the occurrence of localized buckling, and economic efficiency. Namely, it is more economical if the flange width is longer, however, if flange bending and the occurrence of localized buckling are taken into account, then desirable maximum and minimum values, and also a more desirable maximum value for the flange width can be decided.

Firstly, a desirable maximum value for a flange width L will be described. If the length of the flange width L is increased, then it is possible to decrease the number structural steel materials100that are laid to form a floor structure, and the total number of webs can also be decreased. However, if the length of the flange width L is too long, then bending6of the top flange104of the structural steel materials100(seeFIG. 1B) becomes a problem.

If the plate thickness of the top flange104is taken as t, and if it is assumed that a uniformly distributed load w=2900 N/m2is acting on the top flange104(based on the loading capacity permitted in a business premises according to Enforcement Ordinance of Construction Standards Law—Article 85), then if the maximum bending δ max of the structural steel materials100is set at not more than L/300, by means of the following calculation, a maximum value of the flange width L can be found as a function of t expressed by Formula (4) below.
δ=5wL4/(384EI)≦L/300  (1)

Here, E is Young's modulus. Because w=2900 N/m2, if the load width is taken as 1 m, and unit conversion is performed, then the following is obtained.
w=2.9N/mm  (2)

In the case of the geometrical moment of inertia as well, if a load width b is taken as 1000 mm, the following is obtained.
I=bt3/12=1000t3/12  (3)

If these Formulas (2) and (3) are substituted into Formula (1), and it is taken that E=205000 N/mm2, then the following is obtained.
L/t≦115  (4)

Accordingly, a desirable maximum value for the flange width L is 115 t, namely, 115 times the plate thickness t of the top flange104.

In the above calculations, a maximum value was calculated for the flange width L based on the bending of the structural steel materials100, however, it is necessary to assume a case in which a large out-of-plane bending force is acting on the floor surface of the floor structure, and to evaluate the localized buckling strength of the top flange104.

Therefore, because evaluation is possible provided that the structure resembles a plate material, the maximum value of the flange width L can be calculated by invoking Formula (5) below in order to suppress the occurrence of buckling in the plate material.
L/t≦740/√{square root over (f)}(5)

Here, f is an acting force that is acting on the top flange104in a perpendicular direction relative to the surface of the top flange104, and is set at a value that allows for a safety factor of 3 times a value of 235 N/mm2for the design standard strength F of a typical steel material SS400. Therefore, if f is substituted into Formula (5), the following is obtained.
L/t≦740/√{square root over (135/3)}≈84  (6)
Accordingly, a more desirable value for the flange width L is not more than 84 t, namely, not more than 84 times the plate thickness t of the top flange104. Note that it is possible to appropriately establish (for example, to further extend) the width of the flange width L by providing a rib on the flange. Here, this rib is effective in preventing bending and/or localized buckling, and has a structure that, for example, makes it possible to restrict any bending occurring in the flange to L/300 or less, and that can suppress the occurrence of any localized buckling.

Next, the minimum value of the flange width L will be described. If the flange width L is shortened, it becomes difficult for problems to occur in rigidity (i.e., bending) and strength (i.e., localized buckling), so that what has to be considered when deciding a desirable minimum value for the flange width L is economic efficiency.

Namely, the economic efficiency of the structural steel materials100is decided by the relationship thereof with the flexural rigidity (I/A) per unit surface area.FIG. 6is a graph showing a relationship between the flexural rigidity (I/A) per unit area of the structural steel materials100of the present embodiment and a ratio of the flange width relative to the web height. The two points shown inFIG. 6are where data for the ratios of the flange width relative to the web height and the flexural rigidities (I/A) of the present embodiment shown in the columns (b) and (c) inFIG. 5have been plotted. In addition, the I/A of the box-shaped steel materials10used for the conventional technology is 6374 mm2, and is the value shown by the broken line inFIG. 6. It is desirable for the structural steel materials100to have a value that is not less than the I/A of the box-shaped steel materials10. Accordingly, as can be seen from the graph shown inFIG. 6, a desirable minimum value for the flange width L is ½ the web height.

As a result of the above, the range of the flange width L is desirably not less than ½ the web height, and not more than 115 times the plate thickness of the top flange104, and more desirably not more than84times the plate thickness of the top flange104.

According to the first embodiment of the present invention, by forming a floor structure by laying in parallel with each other adjacent structural steel materials100that are each provided with a web102, a top flange104, and a bottom flange106, it is possible to form a floor structure that is more lightweight than a floor structure which is formed by laying the box-shaped steel materials10that are used in the conventional technology, and it is also possible to obtain improved structural properties. Moreover, because it is possible to stack a plurality of the structural steel materials100, space can be saved during transportation thereby enabling an improvement in the steel material transporting efficiency to be achieved.

Second Embodiment

Next, a structural steel material and floor structure according to a second embodiment of the present invention will be described.FIGS. 7A and 7Bare side views showing the structural steel material and floor structure according to the present embodiment.

As is shown inFIG. 7B, the floor structure according to the present embodiment is formed by laying a plurality of structural steel materials200in parallel with each other. Moreover, as is shown inFIG. 7A, the structural steel materials200according to the present embodiment are provided with a web202, a top flange204, and a bottom flange206. A floor structure is formed in which a top flange204of any one structural steel material200is placed so as to cover a top surface of a bottom flange206of another structural steel material200that is placed adjacently thereto.FIG. 7Bshows a case in which the flange width is 300 mm, and the web height is 175 mm, however, the present embodiment is not limited to this example.

The main structures of the web202, the top flange204and the bottom flange206according to the present embodiment are the same as those of the above described first embodiment, therefore, a detailed description thereof is omitted. As is shown inFIGS. 7A and 7B, in the present embodiment there are further provided a joining portion202athat is formed on a top end portion of the web202, and a projecting portion204athat is formed on an end portion of the top flange204. The joining portion202ahas a surface that is at a lower position than the top surface of the top flange204, and is parallel with the top flange204. The projecting portion204ahas a groove shape that is hollowed out below the top flange204. When any one structural steel material200is joined to another adjacent structural steel material200, as is shown inFIG. 7B, the projecting portion204ais mounted in contact with the joining portion202a, and these two are then joined together by drill screws210. The joining portion202aand the projecting portion204athat have been screwed together are formed at a position below the top flange204. Accordingly, no portion protrudes above the top surface of the top flange204, and it is possible to provide a floor structure that is tightly fit together and has a flat surface.

Here, the drill screws210are an example of a fixing tool, however, the present embodiment is not limited to this example and it is also possible to use semi-finished bolts, high strength bolts, rivets, caulking, welding, or bonding or the like as a fixing tool. Moreover, in the structural steel materials200of the present embodiment, a bent portion206ais formed on an end portion of the bottom flange206. The bent portion206ahas a surface that is parallel with the web202and extends from the bottom flange206in a perpendicular direction relative thereto. When a floor structure is formed by laying a plurality of structural steel materials200in parallel with each other, the bent portions206aare in contact with a bottom end portion202bof the web202of the adjacent structural steel material200.

Next, a description will be given of a construction technique for constructing a floor structure according to a second embodiment of the present invention.FIGS. 8A to 8Dare side views showing a construction technique for the floor structure of the present embodiment.

FIG. 8Ashows a state midway through a process to construct a floor structure, and a bottom flange206is exposed at an end portion thereof. Next, as is shown inFIG. 8B, another new structural steel material200is readied for laying. At this time, the top flange204of the structural steel material200currently being laid is positioned so as to cover the top portion of the bottom flange206of the structural steel material200that was laid previously. Furthermore, the structural steel material200is laid such that the projecting portion204aof the top flange204fits in the joining portion202a. Next, as is shown inFIG. 8C, drill screws210are screwed from the top portion of the projecting portion204atowards the joining portion202a, thereby joining together the two structural steel materials200.FIG. 8Dshows a state in which a newly laid structural steel material200is joined to the adjacent structural steel material200.

As has been described above, according to the floor structure and structural steel materials200of the present embodiment, because a plurality of structural steel materials200are joined together in an integrated unit by means of the drill screws210or the like, the structural steel materials200are prevented from moving independently within the plane of the floor structure. Accordingly, it is possible to increase the in-plane shear rigidity of the floor structure.

Third Embodiment

Next, a structural steel material and floor structure according to a third embodiment of the present invention will be described.FIGS. 9A and 9Bare side views showing the structural steel material and floor structure according to the present embodiment.FIG. 10is a side view showing a state in which the structural steel materials according to the same embodiment are stacked.

As is shown inFIG. 9B, the floor structure according to the present embodiment is formed by laying a plurality of structural steel materials300in parallel with and also adjacent to each other. Moreover, as is shown inFIG. 9A, the structural steel materials300according to the present embodiment are provided with a web302, a top flange304, and a bottom flange306. A floor structure is formed in which a top flange304of any one structural steel material300is placed so as to cover a top surface of a bottom flange306of another structural steel material300that is placed adjacently thereto.FIG. 9Bshows a case in which the flange width is 300 mm, and the web height is 175 mm, however, the present embodiment is not limited to this example.

The main structures of the web302, the top flange304and the bottom flange306according to the present embodiment are the same as those of the above described first embodiment, therefore, a detailed description thereof is omitted. As is shown inFIGS. 9A and 9B, in the present embodiment there are further provided a fitting portion302athat is formed on a top end portion of the web302, and an engaging portion304athat is formed on an end portion of the top flange304. A cross section of the fitting portion302ain the joining portion between the top flange304and the top end portion of the web302is formed in a C shape. The engaging portion304ahas a groove shape that is hollowed out below the top flange304. When any one structural steel material300is joined to another adjacent structural steel material300, as is shown inFIG. 9B, the engaging portion304ais fitted onto the top of the fitting portion302a, and is thereby joined thereto. The method used for this fitting is the same as in the construction technique of the fourth embodiment of the present invention and a description of this embodiment is therefore omitted.

Moreover, in the structural steel materials300of the present embodiment, a bent portion306ais formed on an end portion of the bottom flange306. The bent portion306ahas a surface that is parallel with the web302and extends from the bottom flange306in a perpendicular direction relative thereto. A bent portion302bis also formed on a bottom end portion of the web302. The bent portion302bis bent towards the distal end side of the bottom flange306by the distance of the plate thickness thereof, and has a surface that is parallel with the web302. When a floor structure is formed by laying a plurality of structural steel materials300in parallel with each other, the bent portions306aof the bottom flanges306are in contact with the bent portions302bon the bottom end of the web302of the adjacent structural steel material300.

Because a plurality of the structural steel materials300according to the present embodiment are formed into a single unit so as to form a floor structure with the fitting portions302aand the engaging portions304abeing fitted together, it is easy to position the respective structural steel materials300when this floor structure is being constructed. As a result, on-site workability is facilitated.

Moreover, because the fitting portions302aand the engaging portions304aare fitted together in this floor structure that is constructed using the structural steel materials300according to the present embodiment, the structural steel materials300are prevented by friction force from moving independently within the plane of the floor structure. Accordingly, it is possible to raise the in-plane shear rigidity of the floor structure.

Note that, as is shown inFIG. 10, it is also possible to stack the structural steel materials300according to the present embodiment in the same way as the structural steel materials according to the first embodiment. As a result, when the structural steel materials are being transported, a large number of structural steel materials300can be loaded onto the loading bed of a truck, for example, without occupying any more space than is necessary (i.e., is space saving). Namely, it is possible to increase the quantity that can be transported in a single load. As a result, transporting costs can be reduced.

Fourth Embodiment

Next, a structural steel material and floor structure according to a fourth embodiment of the present invention will be described.FIGS. 11A and 11Bare side views showing the structural steel material and floor structure according to the fourth embodiment.

As is shown inFIG. 11B, the floor structure according to the present embodiment is formed by laying a plurality of structural steel materials400in parallel with and adjacent to each other. Moreover, as is shown inFIG. 11A, the structural steel materials400according to the present embodiment are provided with a web402, a top flange404, and a bottom flange406. A floor structure is formed in which a top flange404of any one structural steel material400is placed so as to cover a top surface of a bottom flange406of another structural steel material400that is placed adjacently thereto.

The main structures of the web402, the top flange404and the bottom flange406according to the present embodiment are the same as those of the above described first embodiment, therefore, a detailed description thereof is omitted. As is shown inFIGS. 11A and 11B, in the present embodiment there are further provided a fitting portion402athat is formed on a top end portion of the web402, and an engaging portion404athat is formed on an end portion of the top flange404. A cross section of the fitting portion402ain the joining portion between the top flange404and the top end portion of the web402is formed in a C shape. The engaging portion404ahas a groove shape that is hollowed out below the top flange404. When any one structural steel material400is joined to another adjacent structural steel material400, as is shown inFIG. 9B, the engaging portion404ais fitted onto the top of the fitting portion402a, and is thereby joined thereto.

Furthermore, in the structural steel materials400of the present embodiment, a bent portion406ais formed on an end portion of the bottom flange406. The bent portion406ahas a surface that is parallel with the web402and extends from the bottom flange406in a perpendicular direction relative thereto, and also has a sloping surface whose distal end extends downwards. A sloping portion402bis also formed on a bottom end portion of the web402. The sloping portion402bis bent from the web402towards the distal end side of the bottom flange406, and has a sloping surface that slopes at the same angle as the aforementioned sloping surface of the bent portion406a. In a floor structure in which a plurality of structural steel materials400are laid in parallel with each other, the bent portions406aof the bottom flanges406are in contact with the sloping portions402bon the bottom end of the web402of the adjacent structural steel material400.

When any one structural steel material400is joined to another adjacent structural steel material400, as is shown inFIG. 11B, the sloping portion402bis mounted in contact with the bent portion406a, and these two are then joined together by drill screws410. Here, the drill screws410are an example of a fixing tool, however, the present embodiment is not limited to this example and it is also possible to use, for example, semi-finished bolts, high strength bolts, rivets, caulking, welding, or bonding or the like as a fixing tool.

Next, a description will be given of a construction technique for constructing a floor structure according to a fourth embodiment of the present invention.FIGS. 12A to 12Eare side views showing a construction technique for the floor structure of the present embodiment.

FIG. 12Ashows a state midway through a process to construct a floor structure in which a bottom flange406is exposed at an end portion of the floor structure. Next, as is shown inFIG. 12B, another new structural steel material400is readied for laying. At this time, the engaging portion404aof the structural steel material400currently being laid is placed against the fitting portion402aof the previously laid structural steel material400. Next, as is shown inFIG. 12C, the structural steel material400currently being laid is rotated around the fitting portion402a, thereby fitting the engaging portion404aand the fitting portion402btogether.

Next, as is shown inFIG. 12D, the structural steel material400currently being laid is laid such that the top flange404covers the top portion of the bottom flange406of the adjacent structural steel material400which was laid previously. As a result, the sloping portion402bof the newly laid structural steel material400is in contact with the top surface of the bent portion406aof the previously laid structural steel material400. Next, as is shown inFIG. 12E, drill screws410are screwed from the top portion of the sloping portion402btowards the bent portion406a, thereby joining together the two structural steel materials400. As a result, the newly laid structural steel material400is joined to the adjacent structural steel material400.

By employing the above described structure, because the structural steel materials400according to the present embodiment are formed into a single unit so as to form a floor structure with the fitting portions402aand the engaging portions404abeing fitted together, it is easy to position the respective structural steel materials400when this floor structure is being constructed. As a result, on-site workability is facilitated.

Furthermore, according to the floor structure and structural steel materials400of the present embodiment, because a plurality of structural steel materials400are joined together in an integrated unit by means of the drill screws410or the like, and also because the fitting portions402aand the engaging portions404aare fitted together, the structural steel materials400are prevented by friction force from moving independently within the plane of the floor structure. Accordingly, it is possible to raise the in-plane shear rigidity of the floor structure.

Note that, in the above described third and fourth embodiments, a description is given of a case in which the fitting portions302aand402aand the engaging portions304aand404aare formed on the top flanges304and404side, however, the present invention is not limited to this. It is also possible for the fitting portions and engaging portions to be formed on the bottom flange side. In this case, conversely to the example shown inFIGS. 12A through 12E, a floor structure can be constructed by laying the structural steel materials with the engaging portion fitted into the fitting portion by lifting up the structural steel material from below.

Fifth Embodiment

Next, a structural steel material and floor structure according to a fifth embodiment of the present invention will be described.FIGS. 13A and 13Bare side views showing the structural steel material and floor structure according to the present embodiment.FIG. 14is a perspective view showing the structural steel material and floor structure according to the present embodiment.

As is shown inFIG. 13BandFIG. 14, the floor structure according to the present embodiment is formed by laying a plurality of structural steel materials500in parallel with each other. Moreover, as is shown inFIG. 13A, the structural steel materials500according to the present embodiment are provided with a web502, a top flange504, and a bottom flange506. A floor structure is formed in which a top flange504of any one structural steel material500is placed so as to cover a top surface of a bottom flange506of another structural steel material500that is placed adjacently thereto.

The main structures of the web502, the top flange504and the bottom flange506according to the present embodiment are the same as those of the above described first embodiment, therefore, a detailed description thereof is omitted. As is shown inFIGS. 13A and 13B, in the present embodiment, when a floor structure is being formed by laying the structural steel materials500in parallel with each other, the webs502are provided so as to be inclined relative to the installation surface. In addition, thin portions504aand506athat each have a thinner plate thickness are formed on the distal end sides of the bottom surface of the top flange504and the top surface of the bottom flange506, and thin portions504band506bare formed on the web502side of the top surface of the top flange504and the bottom surface of the bottom flange506. These thin portions504a,504b,506a, and506beach have a surface that is parallel to the top flange504and the bottom flange506. The thin portion504aof the top flange504is in contact with the thin portion504bof the top flange504of the adjacent structural steel material500, and the thin portion506bof the bottom flange506is in contact with the thin portion506aof the bottom flange506of the adjacent structural steel material.

As is shown inFIGS. 13B and 14, an end portion steel material510is laid at an end portion of the floor structure. The end portion steel material510has a web512, a flange514, and a flange516. A thin portion514ahaving a thin plate thickness is formed at a distal end of the flange514. When the end portion steel material510is placed up against a structural steel material500so as to cover the bottom flange506, the thin portion514ais in contact with the thin portion504bof the structural steel material500, and the flange516is in contact with the thin portion506aof the structural steel material500. In contrast, when the end portion steel material510is placed up against a structural steel material500such that the flange514is covered by the top flange504of the structural steel material500, the thin portion514ais in contact with the thin portion506bof the structural steel material500, and the flange516is in contact with the thin portion504aof the structural steel material500.

Next, a description will be given of an appropriate range for the angle of inclination of the web of the structural steel material according to the present embodiment.FIGS. 15A and 15Bare side views showing the structural steel material according to the present embodiment in simplified form.FIGS. 16A and 16Bare a conceptual view showing the structural steel material according to the same embodiment, and a graph showing a relationship between structural properties relating to flexural rigidity and the flange width and web height of the structural steel material according to the same embodiment.

The angle of the web502relative to the top flange504and the bottom flange506is within a range between an angle θ1and an angle θ2shown inFIG. 16A. In addition, in order to decide an appropriate range for the angle of inclination of the web502, the plate thickness t of the web502, the top flange504, and the bottom flange506was set at 4.5 mm, the flange width was set at 200 mm, and the height H of the structural steel material500was set at 200 mm. The value of the geometrical moment of inertia (I/A) per unit surface area when the angle of the web502was changed was then examined.

The geometrical moment of inertia (I/A) per unit surface area when the angle of the web502was changed from 20° to 160° is shown in the graph inFIG. 16B, and is represented by a curve whose peak value is at 90°. The broken line inFIG. 16Bfurther shows the value of the geometrical moment of inertia (I/A) per unit surface area of the box-shaped steel10according to the conventional technology which is shown in the column (a) inFIG. 5. As a result, it can be seen that if the angle of the web502is within a range between approximately 30° and 150°, then the structural steel material500of the present embodiment has structural properties (i.e., the geometrical moment of inertia (I/A) per unit surface area) either equivalent to or superior to box-shaped steel10of the same height.

Accordingly, in the present embodiment, it is desirable for the angle of the web502to be within a range between approximately 30° and 150°. When the angle of the web502is within this range, then the present embodiment is able to exhibit a higher flexural rigidity using less and lighter material compared to the conventional technology. Note that, as is shown inFIG. 16A, when the angle of the web502is 30° or 150°, if the web height is taken as H, then the web length is taken as 2H. Moreover, in the above described example, the plate thickness t of the web502, the top flange504, and the bottom flange506was set at 4.5 mm, the flange width was set at 200 mm, and the height H of the structural steel material500was set at 200 mm, however, the present embodiment is not limited to this example, and it is possible to modify these dimensions. By making the angle of the web502within a range between approximately 30° and 150° even if the structural dimensions (i.e., the balance) of the structural steel material500are changed, it is possible to obtain structural properties (i.e., the geometrical moment of inertia (I/A) per unit surface area) either equivalent to or superior to box-shaped steel10of the same height.

Sixth Embodiment

Next, a structural steel material and floor structure according to a sixth embodiment of the present invention will be described.FIGS. 17A to 17Fare side views showing the structural steel material and floor structure according to the present embodiment.

In the above described first embodiment, a case is described in which the top flange104is formed extending from the top end portion of the web102in one direction only, and in which the bottom flange106is formed extending from the bottom end portion of the web102only in the opposite direction from the direction in which the top flange extends, however, the present invention is not limited to this example.

For example, as is shown inFIG. 17A, it is also possible for a protruding portion104bto be formed extending from the top end portion of the web102in the opposite direction from the direction in which the top flange extends. At this time, a step portion104cis formed on an end portion104aside of the top flange104. Moreover, as is shown inFIG. 17C, it is also possible to form a protruding portion106bthat extends from the bottom end portion of the web102in the same direction in which the top flange extends. At this time, a step portion106cis formed on an end portion106aside of the bottom flange106. Moreover, as is shown inFIG. 17E, it is also possible for these protruding portions104band106bto be formed respectively on the top end portion and bottom end portion of the web102. At this time, the step portions104cand106care formed respectively on the top flange104and the bottom flange106.

The protruding portions104band106bhave the same plate thickness as the top flange104and the bottom flange106. Moreover, the protruding portions104band106bare formed within the same plane respectively as the top flange104and the bottom flange106. The step portions104cand106care formed by their respective distal ends being folded such that the sizes of their step portions are equivalent to the plate thickness of the top flange104and the bottom flange106, and also have surfaces that are parallel respectively with the top flange104and the bottom flange106.

In a floor structure in which a plurality of these structural steel materials100are laid together, as is shown inFIGS. 17B,17D, and17F, any one of the protruding portions104band106bis in contact with a step portion104cor106cof the adjacent structural steel material100. As a result of the protruding portions104band106bbeing in contact with the step portions104cand106cin this manner, it is easy to position the respective structural steel materials300when this floor structure is being constructed. As a result, on-site workability is facilitated. In addition, because the top surfaces of the top flanges104of structural steel materials that are laid adjacent to each other are located on the same plane, it is possible to provide a floor structure that has a smooth surface.

Note that, in the above described embodiment, as is shown inFIGS. 17A through 17F, a case is described in which the step portions104cand106care formed by bending the distal end portions of the top flange104and the bottom flange, however, the present invention is not limited to this. For example, it is also possible to provide these step portions by making the distal end portions of the top flange104and the bottom flange thinner than the other portions thereof.

Seventh Embodiment

Next, a floor structure according to a seventh embodiment of the present invention will be described.FIG. 18is a side view showing the floor structure according to the present embodiment.

The floor structure according to the present embodiment is provided with the structural steel materials400of the above described fourth embodiment, and is additionally provided with floor beam structural steel materials700. The floor beam structural steel materials700have a web702, a top flange704, and a bottom flange706, and also have a fitting portion702a, an inclined portion702b, and an engaging portion704a. The web702, the top flange704, the fitting portion702a, the inclined portion702b, and the engaging portion704aare the same as those in the above described fourth embodiment, therefore, a detailed description thereof is omitted.

The bottom flange706protrudes in a downward direction below the bottom end portion of the web702. The bottom flange706has two surfaces that are parallel to the web702, and a surface that is parallel to the top flange704, and has a U-shaped cross section. A bent portion706awhose distal end points downwards is formed on a distal end of the bottom flange706. When a floor beam structural steel material700is laid so as to form at least a portion of a floor structure, the bent portion706aof the bottom flange706is in contact with the inclined portion402bof the bottom end of the web402of the adjacent structural steel material400. In addition, when a structural steel material400is joined to a floor beam structural steel material700, as is shown inFIG. 18, the inclined portion402bis mounted on the bent portion706aand in contact therewith, and these two are then joined together by drill screws410.

When the floor beam structural steel materials700are laid in a floor structure, because they protrude below the bottom flanges406of the structural steel materials400, and have a U-shaped cross section, they function as beam components for the floor structure. Accordingly, in an erected construction which uses the floor beam structural steel materials700, it is possible to omit joists such as binding joists, and thereby achieve an improvement in workability and a lift in profitability.

The cross section of the bottom flange706of the floor beam structural steel material700is not limited to being a U-shaped cross section, as is described above, and, provided that a bulge portion is formed that bulges downwards from the bottom end portion of the web702, it is also possible for this cross section to be formed in a semi-circular shape or the like.

Eighth Embodiment

Next, a floor structure according to an eighth embodiment of the present invention will be described.FIG. 19is a side view showing the floor structure according to the present embodiment.

The floor structure according to the present embodiment is provided with the above described structural steel materials100according to the first embodiment, and with noise-proofing material180. The structural steel materials100are the same as the structural steel materials100in the above described first embodiment, therefore, a detailed description thereof is omitted.

The noise-proofing materials180are provided with a bag182, and with granular material184. The bag182may be formed, for example, from an elastic material. The granular material184may be formed, for example, by reduced iron pellets. By placing the noise-proofing materials180inside a floor structure which is formed by the structural steel materials100, the present embodiment makes it possible to prevent noise and vibration being transmitted from a floor above to a floor below. Note that, instead of the noise-proofing material180, it is also possible to place a weight or a mechanical damper or the like inside the structural steel materials in order to control the characteristic value of the floor vibration.

According to the present embodiment, when a floor structure is being constructed, a noise-proofing material180is placed on top of the bottom flange106of a structural steel material100, and the next structural steel material100to be laid is then installed so as to cover this bottom flange106and noise-proofing material180. When laying the box-shaped steel10of the conventional technology, it is necessary to insert the noise-proofing materials180via end portions of the box-shaped steel10so that the construction process is extremely time-consuming. In contrast, according to the present embodiment, because the noise-proofing materials180can be mounted on the bottom flanges106while the structural steel materials100are being laid, it is possible to reduce both the time and the costs needed for the construction process.

Note that the present invention is not limited to cases in which the noise-proofing material is placed on top of the bottom flange106, and the noise-proofing material may also be suspended from the top flange104. Furthermore, a noise-proofing material may also be formed by filling the space between the bottom flange and the top flange with concrete.

Ninth Embodiment

Next, a floor structure according to a ninth embodiment of the present invention will be described.FIGS. 20A and 20Bare perspective views showing a structural steel material according to the present embodiment.FIG. 21is a perspective view showing a structural steel material and the floor structure according to the present embodiment.

As is shown inFIG. 20A, connection protruding portions605are formed on a structural steel material600according to the present embodiment so as to extend along an end portion604aof a top flange604in the longitudinal direction thereof. In addition, connection aperture portions603are formed in a step portion604bthat is provided in the vicinity of a join portion between a top end of a web602and a top flange604of the structural steel material600. As is shown inFIG. 21, the connection protruding portions605are inserted into the connection aperture portions603, so that the two can be engaged with each other. It is desirable for the connection aperture portions603to be formed as small as possible, while being sufficiently large considering the size of the connection protruding portions605. The smaller the connection aperture portions603, the stronger the mutual connection between adjacent structural steel materials600can be made. A plurality of both the connection aperture portions603and the connection protruding portions605are provided separate from each other. The step portion604bis formed such that a top surface of a step portion606bis positioned below a top surface of the top flange604. The length in the longitudinal direction of the connection protruding portions605, and the spacing between adjacent connection protruding portions605can be appropriately set, and it is not necessary for these to be the same length or to be placed at a uniform spacing.

Connection protruding portions609are formed extending along an end portion606aof a bottom flange604in the longitudinal direction thereof. In addition, connection aperture portions607are formed in a step portion606bthat is provided in the vicinity of a join portion between a bottom end of the web602and a bottom flange606. The connection protruding portions609are inserted into the connection aperture portions607, so that these two can be engaged with each other. A plurality of both the connection aperture portions607and the connection protruding portions609are provided separate from each other. The step portion606bis formed such that the top surface of the step portion606bis positioned below a top surface of the bottom flange606.

As is shown inFIGS. 20A and 21, the connection protruding portions605and609are plate-shaped components that are elongated in the longitudinal direction of the structural steel materials600, while, as is shown inFIGS. 20A and 21, the connection aperture portions603and607are slit-shaped apertures that extend in the longitudinal direction of the structural steel materials600. The present invention is not limited to this, however, and the connection protruding portions may be rod-shaped projecting components instead of plate-shaped components, while the connection aperture portions may be circular or angular apertures that conform to the rod-shaped connection protruding portions.

As is shown inFIG. 21, a floor structure is formed by laying the structural steel materials600according to the present embodiment in parallel with each other. In addition, by placing end portions in the longitudinal direction of the structural steel materials600on a top surface of a beam component12, the structural steel materials12are laid with stability as the floor structure of an erected construction.

Note that, inFIGS. 20A and 21, a case is shown in which the connection protruding portions605and609are formed perpendicularly relative to the surface of the top flange604and the surface of the bottom flange606respectively, however, the present invention is not limited to this example. For example, as is shown inFIG. 20B, it is also possible for connection protruding portions615and619to protrude respectively in a direction parallel to the surface of the top flange604and in a direction parallel to the surface of the bottom flange606. At this time, unlike the connection aperture portions603and607shown inFIGS. 20A and 21, connection aperture portions613and617are formed opening in a perpendicular direction relative to the web602. The connection protruding portions615and619of one structural steel material600are inserted into the connection aperture portions613in617of another structural steel material600which is adjacent to the first structural steel material600. In addition, although omitted from the drawings, it is also possible for the connection protruding portions to be formed at an obtuse angle or at an acute angle relative to the surface of the top flange604and to the surface of the bottom flange606. By employing the structure, the manufacturability and workability of the floor structure is increased.

According to the floor structure of the present embodiment, because joins between the top flange604and the bottom flange606of adjacent structural steel materials600are further strengthened, it is possible to increase the in-plane shear rigidity of the floor.

Tenth Embodiment

Next, a floor structure according to a tenth embodiment of the present invention will be described.FIGS. 22A and 22Bare side views showing a structural steel material according to the present embodiment. In the above described embodiment, a case is described in which the structural steel materials independently form a floor structure, however, in actual fact, the floor surface is only completed when a finishing material is formed on top of the floor structure. In the present embodiment, this finishing material is prepared in advance.

As is shown inFIG. 22A, an aerated lightweight concrete panel (ALC panel)802is laid on a top surface of the top flange604of a structural steel material600of the present embodiment, and is affixed thereto. Plasterboard804or the like is then laid on a top surface of the aerated lightweight concrete panel (ALC panel)802. If these board materials are formed in advance as a single unit together with the structural steel materials600, then the number of on-site tasks to be performed can be reduced. As a result, it is possible to improve the workability of the floor structure and to also improve the overall workability of the construction job. In addition, as is shown inFIG. 22B, by laying a plurality of the structural steel materials600in parallel with each other, a floor structure and a floor surface made up of board materials are formed at the same time.

Note that the board material that is laid on and affixed to the top surface of the top flange604may be a concrete board, a wooden board (e.g., structural plywood, laminated lumber or the like), slate, a ceramic board, a glass wool board, a metal panel, or a ceramic-based siding board (e.g., a slag cement perlite board) or the like.

Eleventh Embodiment

Next, a floor structure according to an eleventh embodiment of the present invention will be described.FIG. 23is a perspective view showing a structural steel material and the floor structure according to the present embodiment.FIGS. 24A to 24Gare perspective views showing a structural steel material according to the present embodiment.

In the above described ninth embodiment, a case is described in which, as is shown inFIG. 21, the structural steel members600are laid such that the bottom surface of the bottom flange606is in contact with the beam component12at end portions in the longitudinal direction of the structural steel materials600, however, the method of connecting structural steel materials to beam components of the present invention is not limited to this example.

In the present embodiment, as is shown, for example, inFIGS. 23 and 24D, a notch portion902is provided in an end portion in the longitudinal direction of the bottom flange606and the web602of the structural steel material600, and the structural steel material600is connected to the top surface of the beam component12via the notch portion902. A step portion601that is parallel with the top flange604and the bottom flange606is provided in the web602of the structural steel material600. When the notch portion902is connected to the top of the beam component12, the step portion601and the web602support the structural steel material600.

Because this structure is employed, the height of the floor structure from the top surface of the beam component12is the same as the height from the notch portion902to the top flange604. As a result, the height of the floor structure from the top surface of the beam component12is lower compared with when the structural steel material600is laid with the bottom surface of the bottom flange606of the structural steel material600in contact with the top of the beam component12, as is shown inFIG. 21. This makes it possible to lower the floor level of each floor of an erected construction.

Note that the notch portion of the present invention is not limited to the example shown inFIGS. 23 and 24D, and notch portions such as those shown, for example, inFIGS. 24A to 24CandFIGS. 24E to 24Gmay also be used. In the example shown inFIG. 24A, instead of the step portion601being provided in the web602, a notch portion904is formed by cutting an end portion in the longitudinal direction of a step portion604b, the web602, and the bottom flange606. In the example shown inFIG. 24B, a notch portion906is formed by cutting an end portion in the longitudinal direction of the web602and the bottom flange606. Here, the notch portion906extends part way in the height direction of the web602. In the example shown inFIG. 24C, in addition to the notch portion906shown inFIG. 24B, there is also provided a bent portion908. The bent portion908has a surface that is parallel to the top flange604and the bottom flange606. As is shown in this example, the notch portion of the present invention is not limited to being formed by cutting a portion of a structural steel material, and it may also be formed by bending.

In the example shown inFIG. 24E, in addition to the notch portion906shown inFIG. 24B, there is also provided a bent portion910. The bent portion910is formed when a steel material having an L-shaped cross section is connected to the surface of the web602. In the example shown inFIG. 24F, a web610is formed so as to be at an obtuse angle relative to the top flange604, and a bent portion912is formed so as to extend in parallel with the surface of the top flange604in the direction of the top flange604. The web602is perpendicular to the bottom flange606, and is connected to an end portion of the bent portion912. In this example, the notch portion is formed by cutting the web602and the bottom flange606at an end portion in the longitudinal direction thereof.

In the example shown inFIG. 24G, in addition to the notch portion902shown inFIG. 24D, there is also provided a bent portion914. The bottom flange606has a bent portion612which is bent at an end portion in the longitudinal direction thereof so as to be at the same height as the step portion601. The bent portion914is formed at an end portion of the bent portion612so as to have a surface that is parallel with the top flange604and the bottom flange606. By employing this structure, the structural steel material600is supported at an end portion in the longitudinal direction thereof on a top surface of structural framework such as the beam component12by means of the bent portion914and the step portion601.

Preferred embodiments of the present invention are described above with reference to the attached drawings, however, it is to be understood that the present invention is not limited to these examples. It is clear that one skilled in the art may consider various alterations and modifications within the categories described by the range of the claims, and it should be understood that these alterations and modifications would naturally also form part of the technical range of the present invention.

For example, in the above described embodiments, a description is given of a case in which the web102, the top flange104, and the bottom flange106are flat steel plates, however, the present invention is not limited to this example. A description will now be given of a variant example of the present invention with reference toFIGS. 25Athrough25D.FIGS. 25A through 25Dare side views showing the structural steel material according to the first embodiment of the present invention. For example, as is shown inFIG. 25A, it is also possible for a rib150to be formed on the web102, and, as is shown inFIG. 25B, it is also possible for a rib152to be formed on the bottom flange106. These ribs150and152are planar materials that are perpendicular respectively to the web102and the bottom flange106on which the ribs150and152are respectively provided and that extend in the longitudinal direction of the structural steel material100. The ribs150and152are shorter than the height of the web102and the widths of the top flange104and the bottom flange106. Note that, although not shown in the drawings, it is also possible for a rib to be formed on the top flange104.

Moreover, as is shown inFIG. 25C, it is also possible for ribs154to be formed on the top flange104and the bottom flange106, and, as is shown inFIG. 25D, it is also possible for a rib156to be formed on the web102. The ribs154and156protrude on one surface side so that a groove is formed on the other surface side, and they extend in the longitudinal direction of the top flange104, the bottom flange106, and the web102.

Note that a rib that is formed on the web102so as to protrude in the direction in which the bottom flange106extends may also function as a connection surface that is provided at a position below the top surface of the top flange. In this case, the distal end portion of the top flange104of the structural steel material100that is laid adjacent thereto is connected to the rib that is also functioning as a connection surface.

The present variant example makes it possible as a result of the ribs150,152,154, and156being formed to improve the out-of-plane flexural rigidity and improve the localized buckling strength of plate elements such as the web102, the top flange104, and the bottom flange106. Accordingly, it is possible to lighten the weight of the structural steel materials100which, in turn, makes it possible to reduce manufacturing costs and increase profitability.

A description will now be given of another variant example of the structural steel material according to the first embodiment of the present invention with reference toFIGS. 26A and 26BandFIGS. 27A and 27B.FIGS. 26A and 26Bare side views showing a variant example of the structural steel material according to the first embodiment.FIGS. 27A and 27Bare side views showing a variant example of the structural steel material according to the first embodiment. In the above described embodiment, the end portion104aof the top flange104is in contact with the top end portion102aof the web102, and the end portion106aof the bottom flange106is also in contact with the bottom end portion102bof the web102. However, the present invention is not limited to this example. For example, as is shown inFIG. 26A, it is also possible to form a structural steel material100in which the bottom flange106has a shorter width than the top flange104. If a floor structure is formed by laying a plurality of these structural steel materials100parallel to each other, then an aperture portion is formed between the bottom end portion102bof the web102and the end portion106aof the bottom flange106on the bottom surface side of the floor structure. Moreover, as is shown inFIG. 26B, by laying a combination of the structural steel materials according to the present variant example and the structural steel materials100in which the lengths of the top flange104and the bottom flange106are equal, it is possible to form aperture portions only in locations where they are necessary on the bottom surface side of the floor structure.

According to the present variant example, as a result of structural steel materials100in which the bottom flanges106have a shorter width than the top flanges104being used for a floor structure, it is possible to insert metal fittings that are used to suspend a ceiling or rafters into the aperture portions that are formed in the bottom surface of the floor structure. As a result, it is possible to improve the workability of an erected construction. Furthermore, it is also possible to install dampers or piping equipment806, or electrical cables or the like inside the floor structure through the aperture portions formed in the bottom surface of the floor structure.

Conversely to the variant example shown inFIGS. 26A to 26B, as is shown inFIG. 27A, when a floor structure is formed by laying in parallel with each other a plurality of structural steel materials100whose top flange104has a shorter width than the bottom flange106, then an aperture portion is formed between the top end portion102aof the web102and the end portion104aof the top flange104on the top surface side of the floor structure. Moreover, as is shown inFIG. 27B, by laying a combination of the structural steel materials according to the present variant example and the structural steel materials100in which the lengths of the top flange104and the bottom flange106are equal, it is possible to form aperture portions only in locations where they are necessary on the top surface side of the floor structure.

According to the present variant example, as a result of structural steel materials100in which the top flanges104have a shorter width than the bottom flanges106being used for a floor structure, it is possible to install dampers or piping equipment, or electrical cables808or the like inside the floor structure through the aperture portions formed in the top surface of the floor structure. This enables post-installation maintenance to be performed via the aperture portions.

Further variant examples of the structural steel material according to the first embodiment of the present invention will now be described with reference toFIGS. 28A to 28C.FIGS. 28A to 28Care side views showing variant examples of the structural steel material according to the present embodiment. The present invention is not limited to cases in which the web, the top flange, and the bottom flange are flat steel plate components. For example, as is shown inFIG. 28A, it is also possible for bent ribs1006having a waveform cross section to be provided on the bottom flange106or the top flange104. Moreover, as is shown inFIG. 28B, it is also possible for a bent rib1002to be provided on the web102. The bent rib1002is bent either once or a plurality of times over the height direction of the web102. As is shown inFIG. 28C, it is also possible to provide a bent rib1008in the bottom flange106or the top flange104. The bent rib1008is bent either once or a plurality of times over the direction in which either the bottom flange106or the top flange104extends. By employing these structures, it is possible to improve the out-of-plane flexural rigidity and improve the localized buckling strength of plate elements such as the web102, the top flange104, and the bottom flange106.

Moreover, in the above described embodiments, cases are illustrated in which the web, the top flange, and the bottom flange are plate-shaped components without any holes in them, however, the present invention is not limited to such examples. For example, it is also possible to use plate-shaped components in which through holes or through grooves have been formed in the web, top flange, or bottom flange.

INDUSTRIAL APPLICABILITY

It is possible to provide a new and improved floor structure that makes it possible to reduce the costs involved both in manufacturing the floor structure and in transporting the steel materials used in the manufacturing thereof.