KR20160149524A - Formed steel beam having neutral axis lifting elements and composite beam using the same - Google Patents

Abstract

The present invention relates to a steel beam for constituting a steel concrete composite beam in which a steel plate is made of a permanent formwork on a cross-section enclosure and a concrete is filled in a section, and more particularly to a composite beam using the same, The present invention relates to a steel beam that is stable even under a construction load and has an end reinforcement member and is improved in shear resistance, and to a composite beam using the same.
A steel material having a neutral axis elevating member according to a preferred embodiment of the present invention includes: a bending steel plate unit having a U- A height forming member coupled to the bending steel plate unit such that the bending steel plate unit has a height that protrudes to the upper portion of the bending steel plate unit at regular intervals in the longitudinal direction central portion of the bending steel plate unit; A slope member extending horizontally from both ends of the phase current to an upper end of the slope member and horizontally extending from an extending end of the slope member to be connected to the upper end of the upper current height member, And a strut reinforcement which is coupled in the cross section of the steel plate unit and installed in the longitudinal direction of the bending steel plate unit.

Description

[0001] The present invention relates to a steel beam having a neutral axis elevating member and a composite beam using the same,

The present invention relates to a steel beam for constituting a steel concrete composite beam in which a steel plate is made of a permanent formwork on a cross-section enclosure and a concrete is filled in a section, and more particularly to a composite beam using the same, The present invention relates to a steel beam that is stable even under a construction load and has an end reinforcement member and is improved in shear resistance, and to a composite beam using the same.

Steel Concrete Composite steel beam and concrete are made to behave as a single member, so that when the bending moment is applied, most of the compressive stress is made to be borne by the concrete and tensile stress is made to be imposed by the steel material. It is possible to reduce the stratification of the beam span and to increase the resistance strength and resistance stiffness of the beam section, thereby enabling the long span structure and increasing the extreme performance and deformation performance.

Steel Concrete Composite has been developed for a long time, one of which is a steel plate permanent composite composite beam in which the section of steel is concentrated on the tensile side of the structural member and the concrete is filled in. This is because the concrete is restrained by the U-shaped steel beam, and the flexural rigidity is increased. Therefore, the concrete is not exposed, and cracking and neutralization are prevented, thereby improving the durability. In addition, since the concrete of the composite beam and the slab is cured by being poured integrally, it is an economical and environmentally friendly method because structural integrity is secured and no separate formwork is used.

However, the U-shaped steel material is unstable due to the open cross-section during the construction stage before it is combined with concrete. The construction load causes the U-shaped steel beam to open. Especially, the cross-sectional compressive force acting on the compressive side of the upper part of the neutral shaft is unstable by making the open section more widened. In addition, both ends of the U-shaped steel beam are installed on both column members, and the construction load acts as a large shear force at the ends, so that local deformation may occur at the ends of the steel beam.

As a background of the present invention, there is a patent registration No. 10-1372643, 'No-form composite beam and its manufacturing method' (Patent Document 1).

This patent is made up of a cast steel plate lower flange forming a lower face, a cast steel plate web formed perpendicularly to both ends of a cast steel plate lower flange, and a cast steel plate upper flange formed at the upper end of the cast steel plate web, A U-shaped molded steel plate formed by molding a steel plate of a thin plate instead of a die; A portion of both ends of the molded steel plate is welded to the molded steel plate and welded to the molded steel plate so that the portion not buried in the molded steel plate is exposed in the molded steel plate so that it can be engaged with the steel column, An H-section to resist the composite section with the concrete; In order to minimize the cross-section of the steel plate and to eliminate the reinforcement in the field, the composite section is formed with the steel plate, the H-section steel, the concrete or the steel plate and the concrete, A stud bolt made of a stud bolt for an H-shaped weld and a stud bolt for a formed steel plate welded at a predetermined interval to the center of a lower flange of the formed steel plate; We propose a concrete composite structure consisting of concrete to be filled to fill the inside of a steel plate with a part of stud bolt and H - section.

According to the composite view proposed by this patent, the end portion where the maximum moment is applied depends on the stress distribution of the H-shaped section and the concrete is resistant to the cross section, and the mid section of the end section where the end moment acts is U- And concrete is designed to resist cross-section. This method is economical because it can reduce the amount of steel products with high raw material prices. However, the U-shaped steel plate is deformed excessively due to the application step load such as work load, And the thickness and the thickness of the formed steel sheet increase in response to the external force problem, the economical efficiency and the material efficiency are lowered.

Patent No. 10-1372643 'No-shape composite beam and its manufacturing method'

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above problems occurring in the prior art, and it is an object of the present invention to provide a steel beam having a neutral axis elevation member and a composite beam using the steel beam elevation member to overcome instability of an open cross- .

In particular, it is an object of the present invention to provide a steel beam capable of reducing the widening of a cross section of a section opened in a construction step by raising the neutral axis and improving the shear force of the steel beam portion installed on the column member, and a composite beam using the same.

A steel material having a neutral axis elevating member according to a preferred embodiment of the present invention includes: a bending steel plate unit having a U- A height forming member coupled to the bending steel plate unit such that the bending steel plate unit has a height that protrudes to the upper portion of the bending steel plate unit at regular intervals in the longitudinal direction central portion of the bending steel plate unit; A slope member extending horizontally from both ends of the phase current to an upper end of the slope member and horizontally extending from an extending end of the slope member to be connected to the upper end of the upper current height member, And a strut reinforcement which is coupled in the cross section of the steel plate unit and installed in the longitudinal direction of the bending steel plate unit.

The bending steel plate unit includes a bottom plate, both side vertical plates vertically extending upward at both ends of the bottom plate, and an upper plate horizontally extending from the upper end of the vertical plate in a direction different from the bottom plate, And the strut reinforcement can be joined to the upper surface of the lower plate of the bending steel plate unit.

Alternatively, the bending steel plate unit may include a bottom plate, both vertical plates extending vertically upward from both ends of the bottom plate, and an upper plate horizontally extending from the upper end of the vertical plate in a direction different from the bottom plate, And the strut reinforcement can be joined to the inner surface of the vertical plate of the bending steel plate unit.

The height forming member includes an upper horizontal plate and a side leg plate extending downward from both ends of the upper horizontal plate so that an extended end of the side leg plate is coupled to the upper plate of the bending steel plate unit, The current can be coupled to the upper or lower surface of the upper horizontal plate.

Alternatively, the height forming member may be made of a length material of any one of a channel, an angle, a rectangular steel, a square pipe, and a Z-shaped steel, and both ends thereof may be coupled to both upper plates of the bending steel plate unit.

Alternatively, the height forming member may be composed of a length material of any one of a channel, an angle, a rectangular steel, a square or a Z-shaped steel, and both ends thereof may be coupled to the inner surface of the bending steel plate unit so as to protrude to the upper portion of the bending steel plate unit.

Here, the end portion of the bending steel plate unit may be closed because the filling groove is formed in a perforated plate shape, and the end portion of the bending steel plate unit is provided at the steel beam end portion.

On the other hand, a slope member which is inclined downwardly at both ends of the phase current at an image having a length shorter than the phase current of the strut reinforcement member, a bottom current member which extends horizontally at the extending end of the slope member so as to have a longer length than the bottom current of the strut reinforcement member And a second strut stiffener which is coupled to the upper end of the upper portion of the height forming member and is coupled to the end surface of the bending steel plate unit so that the lower end is parallel to the strut stiffener.

Or an inclined member extending horizontally at both ends of the lower end and an upper end extending horizontally at an end of the inclined member, the lower end being connected to the upper end of the height forming member The strand reinforcement strut may further include a strand reinforcing strut which is coupled to an end face of the bending steel plate unit so as to be parallel to the strut reinforcement and is provided inside the strut reinforcement.

A composite beam using a steel beam having a neutral axis elevating member according to another preferred embodiment of the present invention is a steel beam having a neutral axis elevating member; A bottom plate on which both ends are mounted on an upper end of a steel member bending steel plate unit having a neutral axis elevating member; And concrete placed in the bending steel plate unit and in the upper part of the bottom plate.

The steel material having the neutral axis elevating member according to the present invention is reinforced by the inclined material of the strut reinforcement to the end portion of the steel beam so as to prevent the local deformation of the end portion of the steel beam during the construction.

Further, a height forming member is formed on the upper side of the cross-section of the bent steel plate unit having the opened cross section and the upper current of the strut reinforcement member is coupled to the height forming member to raise the neutral axis, There is an effect to mitigate.

The composite beam and the slab can be integrally constructed using the steel beam having the neutral axis elevating member according to the present invention. In the steel beam having the neutral axis elevating member, the upper current configuration of the height forming member and the strut reinforcement is formed on the upper side of the cross- Therefore, it is possible to place the concrete on the site while omitting a separate device for laying the slab cast iron rope, thereby improving the workability.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention, Shall not be construed as limiting.
1 is a perspective view of a steel beam having a neutral axis elevating member according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.
3 is a sectional view of a conventional U-shaped steel beam.
4 is a cross-sectional view showing various embodiments of the bending steel plate unit according to the present invention.
5 is a cross-sectional view illustrating various embodiments of a height forming member according to the present invention.
FIG. 6A is a perspective view of a steel beam having a neutral axis elevating member according to another embodiment of the present invention, and FIG. 6B is a sectional view.
FIG. 7A is a perspective view of a steel beam having a neutral axis elevating member according to still another embodiment of the present invention, FIG. 7B is a sectional view taken along line BB of FIG. 7A, and FIG.
8A is a sectional view of a steel beam having a neutral axis elevating member according to another embodiment of the present invention, and FIG. 8B is a DD sectional view of FIG. 8A.
9 is a cross-sectional view of a composite beam using a steel beam having a neutral axis elevating member according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 is a perspective view of a steel beam having a neutral axis elevating member according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A of FIG.

A steel material having a neutral axis elevating member according to the present invention includes: a bending steel plate unit (10) having a U-shaped cross section with an open top and a predetermined length; A height forming member 20 coupled to the bending steel plate unit 10 so as to have a height protruding to the upper portion of the bending steel plate unit 10 at regular intervals in a longitudinally central portion of the bending steel plate unit 10; An inclined member 32 extending horizontally and inclined downward at both ends of the phase current 31 and the phase current 31 and a lower current 33 extending horizontally from the extending end of the inclined member 32, And a strut stiffener 30 which is composed of an upper plate 31 and a lower plate 33 and is joined to the upper end of the height forming member 20 and the lower plate 33 is coupled to the end of the bending steel plate unit 10.

The bending steel plate unit 10 has a U-shaped cross-section having an upper portion, which is constituted by a permanent mold disposed on the tensile side sheath of the composite beam and filled with concrete. The bending steel plate unit 10 in this embodiment includes a bottom plate 11 and both side vertical plates 12 vertically extending upward from both ends of the bottom plate 11; And an upper plate 13 extending horizontally. The upper plate 13 serves as a form for placing the concrete between the bottom plate 11 and the vertical plate 12, and the top plate 13 is a means for mounting the bottom plate described below when the slab is formed.

The height forming members 20 are joined to each other at the upper end of the bending steel plate unit 10 at regular intervals in the longitudinal direction central portion of the bending steel plate unit 10. That is, the height forming member 20 is configured to be located on the upper side of the cross-section of the bending steel plate unit 10 to raise the position of the neutral axis. When a viewing load, which is a member to be warped, acts, compression occurs at the upper part of the neutral shaft and tension is generated at the lower part of the neutral shaft. The bending steel plate unit 10 composed of the plate elements has an open cross section, which causes instability in the state of the concrete load before the concrete synthesis. In particular, when the large compression force is applied to the upper portion of the neutral axis, buckling of the plate element is problematic. The height forming member 20 is formed on the upper side of the cross section of the bending steel plate unit 10 to raise the position of the neutral axis to make the bending steel plate unit 10 exist on the tensile side as much as possible.

Further, the height forming member 20 is a means for reinforcing the horizontal shear resistance. The steel material having the neutral axis elevating member according to the present invention is formed of a composite beam by installing a bottom plate to be described later and placing concrete inside the steel beam and the top of the bottom plate (the composite beam will be described in detail later with reference to other drawings) . That is, the concrete inserted in the bending steel plate unit 10 constituting the beam and the concrete placed in the upper part of the bottom plate constituting the slab are integrally cast and composed of composite beams. The neutral axis of the composite beam is formed on the upper end side of the bending steel plate unit 10 so that the horizontal shear force is maximized. The resistance against the horizontal force generated between the inner concrete and the upper concrete due to the bending steel unit (10) has a relative slip between the inner concrete and the upper concrete due to the absence of a resistance means other than the pure concrete shear strength There is a problem that sudden destruction can be reached. The height forming member 20 is designed to solve this problem. The height forming member 20 is made of concrete, which is coupled to the upper end of the bending steel plate unit 10 so as to have a height and pushed into the bending steel plate unit 10, Thereby reinforcing the horizontal shear resistance.

The height forming member 20 in this embodiment includes an upper horizontal plate 21 and a side leg plate 22 extending downward from both ends of the upper horizontal plate 21, And is coupled to the top plate 13 of the bending steel plate unit 10.

The strut stiffener 30 includes a slope member 32 extending horizontally downwardly from both ends of the phase current 31 and the phase current 31 formed of horizontal length members, And the lower current 33 is coupled to the upper end of the height forming member 20 and the lower current 33 is coupled into the end face of the bending steel plate unit 10. In this embodiment, The upper current 31 of the stiffener 30 is coupled to the upper horizontal board 21 of the height forming member 20 and the lower current 31 of the strut stiffener 30 is connected to the lower board 11 ).

The phase current 31 of the strut reinforcement 30 is provided on the upper side of the cross section of the bending steel plate unit 10 to raise the neutral axis similarly to the height forming member 20 described above, The ash 32 is a means for reinforcing the end shear force. In the case of a U-shaped steel beam using a thin-walled steel plate, both ends are installed on both column members. In the stage before being combined with the concrete, the construction load acts as a large shear force at the end, and local deformation may occur at the end of the steel beam. The slant member 32 of the strut reinforcing member 30 reinforces the end portion of the steel beam to prevent shear stress. The shape of the slope member 32 can be variously formed. For example, the web portion of a reinforced concrete beam generating sinusoidal heat is idealized by a diagonal compression member having a constant slope of 30 to 60 degrees, It is possible to bend in accordance with the 30-60 ° truss model, which shows a method of placement that resists against the force.

The bottom end 33 of the strut reinforcement 30 is engaged in the end surface of the bending steel plate unit 10 and most preferably the lowermost end of the bending steel plate unit 10 in the present embodiment, (Not shown).

The strut reinforcement 30 may be formed by bending steel bars such as a steel bar, a round bar, and a reinforcing bar. The strut reinforcement 30 is composed of at least one strut reinforcement 30, Are arranged parallel and spaced apart from each other.

3 is a sectional view of a conventional U-shaped steel beam.

In order to form slabs in the construction stage of existing U-shaped steel beams, a U-shaped steel beam upper flange is mounted with a form plate, a deck plate or a precast concrete panel. Such a construction load causes the U-shaped steel beam to open. In particular, the cross-sectional compressive force acting on the compression side of the upper portion of the neutral shaft makes the open cross-section more widened and unstable.

2 and FIG. 3, it can be seen that the neutral axis of the steel beam having the neutral axis elevation member according to the present invention is formed higher than the neutral axis of the conventional U-shaped steel beam (l ₁ > l ₂ ).

The present invention is characterized in that the height forming member 20 is formed on the upper side of the cross section of the bent steel plate unit 10 having an open cross section and the upper forming member 20 is joined to the upper side 31 of the strut stiffener 30 So as to solve the instability of the bending steel plate unit 10 by raising the neutral axis.

4 is a cross-sectional view showing various embodiments of the bending steel plate unit according to the present invention.

4A, the present invention is not limited to this. In the range of providing a U-shaped open cross-section, as shown in FIGS. 4B and 4C, the bending steel plate unit 10 may include a plurality of members ≪ / RTI > The upper plate 13 extends horizontally in a direction different from the lower plate 11a at the upper end of the vertical plate 12. The lower plate 11a includes a lower plate 11a, As shown in FIG. 4B, the lower end of the lower plate 11a is coupled with the lower end of the lower plate 11a through the connecting plate 111, or the lower plate 11a is directly connected .

5 is a cross-sectional view illustrating various embodiments of a height forming member according to the present invention.

The height forming member 20 is not limited to the above-described embodiment shown in Figs. 1 and 2. The height forming member 20 may be formed using various members within the range of forming the height at the upper end of the bending steel plate unit 10, As shown in FIGS. 5A to 5D, various members such as channels, angles, angles, tubes, and Z-shaped steel may be used. 5, the height forming member 20 is shown as being coupled to the upper surface of the upper plate 13 of the bending steel plate unit 10. However, the present invention is not limited thereto, and the bending steel plate unit 10 may be coupled to the inner surface of the vertical plate 12 And may be configured to protrude above the bending steel plate unit 10.

FIG. 6A is a perspective view of a steel beam having a neutral axis elevating member according to another embodiment of the present invention, and FIG. 6B is a sectional view.

In this embodiment, the height forming member 20 includes an upper horizontal plate 21, a side leg plate 22 extending downward from both ends of the upper horizontal plate 21, And a lower horizontal plate 23 extending horizontally in a direction different from that of the flat plate 21. The lower horizontal plate 23 is coupled to the upper plate 13 of the bending steel plate unit 10 at an extended end thereof.

1 and 2, the upper end 31 of the strut reinforcement 30 is coupled to the upper surface of the upper horizontal plate 21 of the height forming member 20, but the present invention is not limited thereto, The upper current 31 of the strut reinforcing member 30 may be coupled to the lower surface of the upper horizontal plate 21 of the height forming member 20 as shown in FIG.

1 and 2, the lower end 33 of the strut reinforcement 30 is coupled to the lower plate 11 of the bending steel plate unit 10, but in the present embodiment, The lower plate 33 is coupled to the vertical plate 12 of the bending steel plate unit 10. [ The lower current 33 of the strut reinforcement 30 is coupled to the end surface of the bending steel plate unit 10 and is most preferably bonded to the bottom plate 11 at the lowermost end of the bending steel plate unit 10 as in the previous embodiment And may be coupled to the vertical plate 12 so as to be positioned in the cross section of the bending steel plate unit 10 as required in the present embodiment.

FIG. 7A is a perspective view of a steel beam having a neutral axis elevating member according to still another embodiment of the present invention, FIG. 7B is a cross-sectional view taken along line B-B of FIG. 7A, and FIG.

In this embodiment, a second strut reinforcing member 30a is further provided. The second strut reinforcing member 30a is configured to be bent in a different shape from that of the strut stiffener 30 so that the bending steel plate unit 10 is sheared at the front end so that the bent shape of the strut stiffener 30 and the second strut stiffener 30a, The number depends on the structural calculation.

Further, in the present embodiment, the end reinforcing lid plate 40 is further provided so as to reinforce the ends of the bending steel plate unit 10 at the closed end. The filling grooves 41 should be drilled for smooth filling of the concrete.

8A is a cross-sectional view of a steel beam having a neutral axis elevating member according to still another embodiment of the present invention, and FIG. 8B is a cross-sectional view taken along the line D-D of FIG. 8A.

In this embodiment, a further moment reinforcing strut 30b is provided. The momentum reinforcing strut 30b has a lower end 31b composed of horizontal lengths and an inclined member 32b extending obliquely upward at both ends of the lower end 31b so as to have an opposite shape to the strut reinforcement 30, And an upper current 33b horizontally extending from the extending end of the inclined member 32b so that the lower current 31b is coupled to the upper end of the height forming member 20 and the upper current 33b is connected to the bending steel plate unit 10 so that the bending steel plate unit 10 has to bear the momentum.

9 is a cross-sectional view of a composite beam using a steel beam having a neutral axis elevating member according to the present invention.

The steel beam 1 having the neutral axis elevating member according to the present invention constructed as described above is provided with a bottom plate 51 and a concrete 50 is installed inside the steel beam and at the top of the bottom plate 51. Various types of members such as Deep Deck, Double T-Deck, and Half Slab as well as a conventional deck plate can be applied to the bottom plate 51. In particular, if the vertical plate 22, which is a sidewall of the bending steel plate unit 20, is constructed of a steel beam manufactured with low durability, a deck deck and a double T-deck can be adopted as the bottom plate 51 to realize a slim floor. According to the structure design, the main iron rope must be laid in the slab. As shown in FIG. 9, the first main iron rope (R1) of the slab is placed on the top of the upper portion of the height forming member and the strut reinforcement The second cast iron rods R2 can be arranged in a lattice.

As described above, according to the present invention, the shear force is reinforced by the inclined material of the strut reinforcement to the end portion of the steel beam, thereby preventing the local deformation of the end portion of the steel beam during the construction.

Further, a height forming member is formed on the upper side of the cross-section of the bent steel plate unit having the opened cross section and the upper current of the strut reinforcement member is coupled to the height forming member to raise the neutral axis, There is an effect to mitigate.

Since the composite beam and the slab can be integrally formed and the upper beam current of the height forming member and the strut reinforcement is formed on the upper side of the cross section of the bending steel plate unit in the steel beam having the neutral axis raising member, It is possible to place the concrete on the spot while omitting it, thereby improving the workability.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. will be. The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

10: Bending steel plate unit 11: Lower plate
12: vertical plate 13: upper plate
111: connecting plate 20: height forming member
21: upper horizontal plate 22: side leg plate
23: Lower horizontal plate 30: Strut reinforcement
31: phase current 32: slope material
33: bottom 30a: second strut reinforcement
30b; Strand 40: End reinforcement cover plate
41: filling groove 50: concrete
51: bottom plate

Claims (10)

A bending steel plate unit (10) having a U-shaped cross section with an open top and a predetermined length;
A height forming member 20 coupled to the bending steel plate unit 10 such that the bending steel plate unit 10 has a height projecting to the upper portion of the bending steel plate unit 10 at regular intervals in a longitudinally central portion of the bending steel plate unit 10; And
An inclined member 32 extending horizontally and inclined downward at both ends of the phase current 31 and the phase current 31 and a lower current 33 extending horizontally from the extending end of the inclined member 32, A strut is provided in the longitudinal direction of the bending steel plate unit 10 so that the phase current is coupled to the upper end of the height forming member 20 and the lower current 33 is joined to the end face of the bending steel plate unit 10, And a reinforcing member (30). The method according to claim 1,
In the bending steel plate unit 10,
A pair of vertical plates 12 vertically extending upward at both ends of the lower plate 11 and an upper plate 13 horizontally extending from the upper end of the vertical plate 12 in a direction different from the lower plate 11 ≪ / RTI >
The height forming member 20 is joined to the upper portion of the upper plate 13 or the vertical plate 12 of the bending steel plate unit 10,
Characterized in that the strut reinforcement (30) is joined to the upper surface of the lower plate (11) of the bending steel plate unit (10). The method according to claim 1,
In the bending steel plate unit 10,
A pair of vertical plates 12 vertically extending upward at both ends of the lower plate 11 and an upper plate 13 horizontally extending from the upper end of the vertical plate 12 in a direction different from the lower plate 11 ≪ / RTI >
The height forming member 20 is joined to the upper portion of the upper plate 13 or the vertical plate 12 of the bending steel plate unit 10,
Wherein the strut reinforcement member (30) is joined to the inner surface of the vertical plate (12) of the bending steel plate unit (10). The method according to claim 2 or 3,
The height forming member (20)
And a side leg plate 22 extending downward from both ends of the upper horizontal plate 21 so that an extending end of the side leg plate 22 is connected to the upper plate 22 of the bending steel plate unit 10, (11) of the strut stiffener (30) is coupled to the upper surface or lower surface of the upper horizontal plate (21). The method according to claim 2 or 3,
The height forming member (20)
And the both ends thereof are coupled to both side upper plates (13) of the bending steel plate unit (10), characterized in that they are made of a length material of any one of a channel, angle, The method according to claim 2 or 3,
The height forming member (20)
And the both ends are connected to the inner surface of the vertical plate 12 of the bending steel plate unit 10 so as to protrude from the upper portion of the bending steel plate unit 10, A steel member having a neutral axis elevating member. The method according to claim 1,
Further comprising an end reinforcing lid plate (40) formed of a perforated plate (41) and provided on the bending steel plate unit (10) at the steel plate end portion,
And the end portion of the bending steel plate unit (10) is closed. The method according to claim 1,
A slope member 32a extending downward at both ends of the phase current 31a and slope member 32a extending downward from both ends of the phase current 31a and a bottom current of the strut stiffener 30 And the lower current 33a horizontally extending from the extending end of the inclined member 32a so as to have a longer length than the lower current 33a. The upper current 31a is coupled to the upper end of the height forming member 20, Further comprising a second strut reinforcing member (30a) fitted in the cross section of the bending steel plate unit (10) so as to be parallel to the strut reinforcing member (30) and provided inside the strut reinforcing member (30) Steel beam with. The method according to claim 1,
An inclined member 32b extending upward at both ends of the lower end 31b and the lower end 31b which are horizontally formed of a horizontal length material and an upper end 33b extending horizontally at an end of the end 32b, So that the lower end 31b is engaged with the upper end of the height forming member 20 and the upper end 33b is engaged with the end surface of the bending steel plate unit 10 so as to be parallel to the strut stiffener 30, Further comprising a moment reinforcing strut (30b) provided on the inner side of the vertical reinforcement strut (30b). A steel beam (1) having the neutral axis elevation member of claim 1;
A steel girder (1) having a neutral axis elevating member, a bottom plate (51) having both ends thereof fixed to the upper end of the bending steel plate unit (10); And
And a concrete (50) placed inside the bending steel plate unit (10) and on the top of the bottom plate (51).

Images