KR101198116B1 - Steel grirder for bridge - Google Patents

Abstract

The present invention relates to a steel girder for bridges, comprising: a first semicircular cross-section steel extending outwardly in a curved cross section; A second semicircular cross-section steel convex outward and facing the first semicircular cross-section steel; A closed cross section steel joined to any one or more of the first semicircular cross section steel and the second semicircular cross section steel to include a closed curve cross section; It is configured to include, the inside is formed a closed cross-section is cut off, to minimize the amount of steel used to implement a higher support capacity for the bending moment, the resistance to wind load is minimized, and can realize a stylish appearance by itself Provide steel bridge girders for bridges.

Description

Steel Girder for Bridges {STEEL GRIRDER FOR BRIDGE}

The present invention relates to a steel girder for bridges, and more specifically, having a small cross section using a smaller amount of steel and having a high supporting ability, the structure is simple by minimizing the amount of reinforcement, and the influence of wind load A steel girder for bridges that can be constructed to be more rigid by receiving less.

Civil structures such as bridges, buildings, and tunnels are constructed using a large number of structural members that can withstand loads such as self-weight and wind pressure of the structure itself. For example, a bridge is provided with a support beam under a floor plate through which a vehicle or people pass, and supports a live load according to the weight of the floor plate and traffic of a vehicle. As such, the civil structure is configured by various structural members to maintain the structure while resisting self-weight and external forces.

FIG. 1A shows a bridge 1 made to be supported by a steel box girder 10 with high carrying capacity. The bridge 1 is constructed by mounting the steel box girder 10 manufactured on the ground, such as a bridge or a shift, and then synthesizing the bottom plate concrete 20 through which a vehicle passes.

Steel box girders 10, which are used as structural members of the bridge 1, are located at a point where the upper flange 11 and the lower flange 12 are spaced apart from the neutral shaft, and thus have a high cross-sectional coefficient. In spite of the high manufacturing cost, the structural member is widely applied to long span bridges due to its excellent ability to resist bending moments.

However, the steel box girder 10 is required to arrange a plurality of longitudinal stiffeners 14 and transverse stiffeners 15 therein in order to maintain a form that exhibits torsional rigidity. Since the process of constructing the reinforcing materials 14 and 15 therein is performed by an operator inside the steel box girder 10, the manufacturing process of the steel box girder 10 is difficult and takes a long time. In addition, the steel box girder 10 has a problem that is more affected by the wind load (W1) because the abdomen 13 forming a side is formed as a vertical flat plate to form a large resistance cross section against the wind.

Incidentally, in the case of constructing the bridge 1 with the steel box girder 10, to improve the aesthetics of the shape of the uniform straight girder 10, as shown in Figure 1b, the curved plate 30 is Although attached to the girder 10 separately, in order to improve the aesthetics, there is a problem that additional cost is required to mount the curved plate 30 rather than the structural member.

In order to solve the above problems, an object of the present invention is to provide a steel girders for bridges that realize a higher bearing capacity for bending moments while minimizing the amount of steel used.

At the same time, it is an object of the present invention to provide a steel girder for bridges having high torsional rigidity and high resistance to torsional deformation even when no reinforcing material is provided therein.

In addition, another object of the present invention is to provide a steel girder for bridges that can minimize the influence of the wind load even in the state installed outside by reducing the resistance by the wind load.

In addition, the present invention is another object to reduce the cost of constructing an aesthetic structure by realizing a refined aesthetic by itself even without mounting a separate member.

The present invention, the first semi-circular cross-section steel extending in a curved convex outward in order to achieve the object as described above; A second semicircular cross-section steel convex outward and facing the first semicircular cross-section steel; A closed cross section steel joined to any one or more of the first semicircular cross section steel and the second semicircular cross section steel to include a closed curve cross section; It is configured to include, there is provided a steel girder for bridges, characterized in that the closed cross section is formed to be cut off from the outside.

It is formed by the first semi-circular cross-section steel and the second semi-circular cross-section steel to form a hollow member consisting of a semicircular curved surface, the closed cross-section steel containing the closed curve cross section of the first semi-circular cross-section steel and the second semi-circular steel By reinforcing the bending stiffness at a position spaced apart from the neutral axis by bonding to any one or more, the section modulus can be increased by using a given steel material, so that the distance from the center is the same while having a high resistance to the bending moment. In order to realize high torsional stiffness, the outer circumferential surface is formed with a curved surface with little variation.

As such, the steel girder for bridges according to the present invention can be maintained in its twisted state without the reinforcement that had to be installed to reinforce the torsional rigidity in the conventional box girder as the torsional rigidity is formed high. .

In addition, the steel girder for bridges according to the present invention can realize a refined appearance without the process of attaching a separate semi-circular cross-section steel as the outer peripheral surface is formed into a curved surface, and at the same time can greatly reduce the resistance due to wind load The effect can also be obtained.

Two or more closed section steels are symmetrically arranged in the bridge steel girders, and when the load is applied in a constant direction such as self-weight, the load direction matches the arrangement direction of the closed section steel, thereby effectively resisting higher bending moments. I can support it.

Therefore, it is effective that the closed cross-section steel is arranged at the position where the tensile or compressive stress is maximized by the external force.

On the other hand, the bridge steel girders may be formed extending in a straight form, it may be formed to have a curvature along the longitudinal direction in accordance with an embodiment of the present invention. The bridge steel girders may be formed in one body in the longitudinal direction, but a plurality of segment members may be connected in the longitudinal direction.

Since the closed cross section steel is provided with a closed cross section, a tension member is installed in the bridge steel girder by introducing a compressive prestress into the bridge steel girder by insisting a tension member on the closed cross section and tensioning the tension member. Even without having a separate cross section for, it is possible to simply implement a higher support capacity for the bending moment acting as a load.

At this time, the tension member which is installed in the closed section steel of the bridge steel girder may be provided with a spacer for maintaining a distance between the inner wall of the closed section steel and the tension member at longitudinal intervals. Thus, even if there is curvature along the longitudinal direction of the member, the tension member can maintain a constant distance from the inner wall of the closed section steel by the spacer, so that the tension material in the closed section of the closed section steel interferes with the inner wall of the closed section steel. It is possible to introduce compression prestress into the steel member without doing so.

On the other hand, a tension material is built into the closed cross-section steel, the compression prestress may be introduced by the tension fixing of the tension material.

The steel girder for bridges thus configured may be used to support the bottom plate of the bridge. For example, the present invention provides a bridge steel girder configured as described above, which is mounted in a plurality of rows as a supporting member on a bridge substructure; A bottom plate concrete installed on an upper side of the bridge steel girder; It includes, the closed cross-section steel provides bridges respectively formed on the upper and lower sides in the direction of gravity.

As described above, the present invention forms a hollow member having a curved shape by the first semicircular cross-section steel and the second semicircular cross-section steel, and the closed cross section steel including the closed curve cross section is formed of the first semicircular cross section steel and the second semicircular cross section steel. Bonded to any one or more of the semi-circular cross-section steel to reinforce the flexural rigidity at a position remote from the neutral axis, thereby providing a steel girder for the bridge to realize a higher support capacity for the bending moment while minimizing the amount of steel used.

In addition, according to the present invention, as the closed cross-sectional shape is formed by using the first semicircular cross-section steel and the second semicircular cross-section steel, the distance deviation from the center to the position of each member is minimized, even if the reinforcement is not installed inside. An advantageous effect having rigidity can be obtained.

In addition, the present invention is not only has a high resistance to the wind load because the outer peripheral surface is formed as a curved surface, and by itself constitutes a sophisticated appearance, so that separate members when used in civil and architectural structures such as bridges, arches, towers, etc. Even without the combination, you can get the added benefit of creating a stylish look.

Figure 1a is a cross-sectional view showing a bridge constructed using a conventional steel box girder
FIG. 1B is an enlarged view of portion 'A' of FIG. 1
Figure 2a is a perspective view showing the configuration of the steel girders for bridges according to the first embodiment of the present invention
FIG. 2B is a cross sectional view of FIG. 2A
3a to 3d sequentially illustrate a method of manufacturing the steel girder for bridges of FIG.
Figure 4 is a view showing the configuration of a steel girder for bridges according to a second embodiment of the present invention
5a to 5e sequentially illustrate a method for manufacturing the steel girder for bridges of FIG.
Figure 6 is a view showing the configuration of a steel girder for bridges according to a third embodiment of the present invention
Figure 7 is a perspective view showing the configuration of the bridge steel girder and arch according to another embodiment of the present invention
Figure 8 is a schematic diagram showing the configuration of the bridge constructed using the steel girder for bridges according to the present invention
9 is a cross-sectional view along the cutting line XX of FIG.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention. However, in describing the present invention, a detailed description of known functions or configurations will be omitted to clarify the gist of the present invention.

As shown in Figure 2a, the structural steel member 100 according to the first embodiment of the present invention, the first semi-circular cross-section steel 110 is formed extending in a curved cross-section convex outward, and the first semicircle is convex outward The second semicircular cross section steel 120 facing the cross section steel 110 and the closed cross section formed by a closed curved cross section and welded to the ends of the first semicircular cross section steel 110 and the second semicircular cross section steel 120 by welding, respectively. It is composed of steel (130, 140). Accordingly, the closed cross-section 101 is formed to be surrounded by the semi-circular cross-section steel (110, 120) and the closed cross-section steel (130, 140) to the outside.

As shown in FIG. 2B, the bridge steel girder 100 configured as described above has a load P acting at a position spaced apart by the maximum distance H from which the closed end steels 130 and 140 can be attached from the center. By arranging up and down at intervals of 180 degrees in the direction, the section modulus resisting the bending moment is maximized. That is, the closed section steels 130 and 140 shown in FIG. 2B have an equivalent relationship with the closed section steels 130 "and 140" shown in FIG. 2C in terms of increasing the section coefficient.

In addition, the closed cross-section steels 130 and 140 shown in FIG. 2B have a closed cross-section to increase their torsional rigidity, thereby stably supporting the external force, while compressing prestress to offset the external force to the steel girders for bridges. In addition to acting as a closed cross-section for accommodating the tension material to be introduced in advance to act more than a closed cross-section steel.

In addition, the steel girders 100 for bridges shown in FIG. 2A form a curved surface as a whole, and thus, when installed outdoors as shown in FIG. 2B, the steel girders 100 do not resist a flat plate surface against the wind load W2. Since it resists, the flow of wind gently diverges on the semicircular cross-section steel (110, 120) receives much less resistance to wind load (W2) than the steel box girder of Figure 1a. Thus, the steel girders 100 for the bridges have an advantageous effect of being able to support the wind load more effectively.

At the same time, since the outer circumferential surface is formed as a curved surface to implement a refined aesthetics by itself even without attaching a separate attachment to the side of the member 100, it can be constructed at a lower cost when used in a structure to realize a refined aesthetics. Is obtained.

Bridge girder 100 according to the first embodiment of the present invention configured as described above, as shown in Figure 3a to prepare a flat plate 130a of the steel material, roll-bending it to the closed end shown in Figure 3b After manufacturing the surface steel (130, 140), and preparing another flat plate (110, 120) and roll bending the semi-circular cross-section steel (110, 120) of semi-circular shape, and then as shown in Figure 3d It is produced by joining the closed section steel (130, 140) by welding (55, 55 ') to the end of the section steel (110, 120). The bridge steel girder 100 is not limited to the above-described fabrication, and may be manufactured in combination with some steps of the manufacturing method of the bridge steel girder 100 ′ of the second embodiment to be described later.

Hereinafter, the bridge steel girder 100 ′ according to the second embodiment of the present invention will be described in detail. However, in describing the second embodiment of the present invention, the same or similar reference numerals are given to the configuration of the second embodiment, and the gist of the second embodiment is clearly defined for the similarities to the configuration and operation of the first embodiment. Duplicate description will be omitted for the sake of brevity.

As shown in FIG. 4, in the steel girder 100 ′ for the bridge according to the second embodiment of the present invention, the tension member 150 is embedded in one of the closed cross-section steels 140 and both ends of the tension member 150. After the fixing plate 70 is installed in the tension member 150, the tension member 150 is tension-fixed so that the compressive prestress is introduced along the longitudinal direction to the steel girder 100 'for the bridge. 100) is different from the configuration.

That is, when the bridge steel girder 100 'receives the bending moment in a predetermined direction, the cross section modulus is increased by the closed section steels 130 and 140 of the bridge steel girder 100', thereby increasing the cross section coefficient. In addition to canceling the bending moment acting on the girder 100 ', the compressive prestress is introduced in a direction opposite to the direction in which the bending moment acts, thereby further reducing the bending moment acting on the steel girders 100' for the bridge. I can support it.

On the other hand, the bridge steel girders (100 ') according to the second embodiment of the present invention by tension-fixing the tension member 150 to introduce a compression prestress in a position eccentric from the neutral shaft, the bridge steel girders (100') Convex flexural deformation occurs. Therefore, depending on the use and installation of the steel girder 100 'for the bridge, the steel girder 100' for the bridge may generate bending deformation (dashed line in Fig. 4) in advance by a predetermined camber. As a result, in the closed cross section steel 140 eccentric from the neutral shaft of the steel girder 100 'for the bridge, the deflection that occurs convexly upward when the compression prestress is introduced in advance, Steel girders 100 'for straight bridges can be manufactured.

Steel bridge girder 100 ′ as described above prepares a steel pipe 110 ′ as shown in FIG. 5A, and then forms a camber (bending deformation) as shown in FIG. 5B by high frequency bending. . Then, as shown in FIG. 5C, the first half-section cross-section steel 110 and the second half-section cross-section steel 120 are manufactured by cutting the steel pipe pipe 110 ′ having the camber formed therein. Meanwhile, as in the above-described first embodiment, the closed end steels 130 and 140 manufactured by roll bending or selected as small steel pipe pipes are prepared and semicircle by welding 55 and 55 'as shown in FIG. 5D. The cross section steel (110, 120) and the closed section steel (130, 140) are joined to produce a steel girders for bridges with cambers. Then, as shown in FIG. 5E, the tension member 140 is inserted into the closed section steel 140 so as to cancel the bending moment acting by external force or its own weight, and the tension member 140 by a hydraulic jack (not shown). After pulling both ends of the () with a predetermined force (F), and fixed to the fixing plate 70, the compression prestress is introduced into the closed section steel material 140 eccentric from the neutral shaft.

In the drawings, a configuration in which a compression material is introduced by inserting a tension member into only one of the closed cross-section steels 130 and 140 is illustrated as an example. The structural steel member distributes the closed section steels 130 and 140 at predetermined rotation angles, such as 120 degrees, 90 degrees, 72 degrees, and 60 degrees, and introduces a prestress by inserting a tension member into the closed section steels to provide a full orientation. It may also be configured to increase the bending stiffness.

On the other hand, although not shown in the drawings, the tension member 150 may be tension-fixed in the closed end steels 130 and 140 to introduce compression prestress into the closed end steels 130 and 140. That is, when the size of the fixing plate is formed smaller than the cross-section of the closed cross-section steel (130, 140) can be introduced into the compression prestress, when the size of the fixing plate interferes with the cross-section of the closed cross-section steel 240 Compression prestress can be introduced into the closed section steel (130, 140).

On the other hand, according to the third embodiment of the present invention, as shown in Figure 6, the bridge steel girder 200 may be formed in a form in which a predetermined camber (or curvature) is formed in a completed state. When a predetermined camber is formed in the bridge steel girder 200 as described above, the tension member 250 for introducing the compression prestress interferes with the inner wall of the closed cross-section steel 240 and the closed cross-section steel 240 with the tension member 250. ) May be broken or local deformation may be caused.

Accordingly, the spacer 260 is pre-installed in the tension member 250 inserted into the closed cross-section steel 240 in advance of the spacer 260 at a longitudinal interval, so that the bridge steel girder 200 has a camber. Even if the tension member 250 is maintained in the closed cross-section steel 240 spaced apart from the inner wall of the closed cross-section steel 240 by the spacer 260.

Specifically, the pair of wedges 262 are fixed to the tension member 250 at intervals in the longitudinal direction, and move along the tension member 250 in the longitudinal direction so as to contact the outer surface of the wedge 262. Possible pairs of retaining nuts 261 are arranged. A female thread is formed on the inner circumferential surface of the fixing nut 261 to engage the male thread on both sides of the spherical spacer 260 in the longitudinal direction. Therefore, the spherical spacer 260 is positioned at the position where the spacer is to be installed, and the pair of wedges 262 are fixed on both sides thereof, and then the spherical spacer 260 is fixed with the fixing nut 261 on both sides thereof. When engaged with the male screw portion of 260, the position of the spherical spacer 260 is firmly fixed on the tension member (250).

Since the tension member 250 is inserted into the closed section steel 240 and the spherical spacer 260 is in contact with the inner wall of the closed section steel 240, friction is generated, so that the spherical spacer 260 can withstand the frictional force. It is sufficient if the position is fixed to the wedge 262. To this end, the spherical spacer 260 is formed with a hole through which the tension member 250 penetrates therein, and a receiving hole for accommodating a portion or more of the wedge 262 is formed.

As the tension member 250 is inserted into the closed end steel 240, the spherical spacer 260 contacts the inner wall of the closed end steel 240 while minimizing the frictional force generated by the tension member 250 of the closed end steel 240. In order to stably space apart from the inner wall, the spacer is preferably spherical in shape. However, according to another embodiment of the present invention, the spacer may be formed in various forms that can be spaced apart from the inner wall of the closed section steel 240, such as elliptical, rectangular.

Through this, even if the steel girder 200 for the bridge according to the third embodiment of the present invention has a predetermined camber, the tension member 250 is closed in the process of fixing the tension member 250 while applying a high tensile force. Since the inner wall of the steel 240 is maintained in an uninterrupted state, the tension member 250 is in contact with the inner wall of the closed cross-section steel 240 in the process of introducing tension precipitating the tension member 250 and introducing the compression prestress. 240 may be prevented from breaking or causing local deformation.

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On the other hand, as shown in Figure 7, the closed cross-section steel 330, 140 of the steel girder 300 for the bridge may be composed of a cross section of a circular pipe shape and a cross section of a square or polygonal pipe shape.

The civil engineering structure shown in FIG. 8 may be configured by using the bridge steel girders 100, 100 ′, 200, 300 and 400 configured as described above and the bridge steel girders having a similar configuration. The two-span bridge 1000 shown in FIG. 8 mounts structural steel girders 100, 100 'in a plurality of rows on a bridge device 60a of a pier and alternating shaft 60, on which the bottom plate concrete 500 is mounted. It is constructed by synthesizing. For example, when the bridge 1000 is a long span bridge with a high common load, the main tower 700 is erected at the first span (left) and the arch 600 is erected at the second span (right). Additional supporting structures may be implemented by connecting the bottom plate concrete 500 or the structural steel girders 100 and 100 ′ with cables 601 and 701.

At this time, the structural steel girders 100 'used as the girder for supporting the bottom plate concrete 500 from the lower side by the load (W) transmitted from the bottom plate concrete 500 as shown in FIG. Since bending warpage occurs, the closed end steels 130 and 140 are arranged at the upper and lower sides at intervals of 180 degrees so as to be aligned in the direction of the load W in order to resist the bending moment. As such, the closed end steels 130 and 140 are arranged at positions spaced apart from the neutral shaft (H), thereby effectively supporting the bending moment due to the load (W) while minimizing the use of expensive steel.

Moreover, since the structural steel girders of FIG. 9 used as support girders form a circular closed cross section therein, the respective steels are arranged at equal distances from the center, and thus have high resistance to torsional rigidity. Therefore, unlike the U-shaped girder or the box-shaped girder, the torsional displacement itself is hardly generated even if a separate reinforcement is not provided inside the semi-circular cross-section steels 110 and 120.

In addition, as the outer shape is formed in a circular shape, it can not only realize a visually refined aesthetic appearance, but also has an excellent ability to shed wind loads (W2) caused by the wind blowing on the bridge along the curved surface, thereby providing excellent resistance to wind loads. Can be.

On the other hand, the steel girder 700 for the bridge used as the main tower 700 of the bridge 1000, because the wind load acts from a variety of orientations, circular closed cross-section steel is evenly distributed around the semi-circular cross-section steel.

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As described above, the present invention forms a hollow member having a curved shape by the first semicircular cross-section steel and the second semicircular cross-section steel, and the closed cross section steel including the closed curve cross section is formed of the first semicircular cross section steel and the second semicircular cross section steel. Bonded to any one or more of the semi-circular cross-section steel to reinforce the flexural rigidity at a position remote from the neutral axis, thereby providing a steel girder for the bridge to realize a higher support capacity for the bending moment while minimizing the amount of steel used.

In addition, according to the present invention, as the closed cross-sectional shape is formed by using the first semicircular cross-section steel and the second semicircular cross-section steel, the distance deviation from the center to the position of each member is minimized, even if the reinforcement is not installed inside. An advantageous effect having rigidity can be obtained.

In addition, the present invention is not only has a high resistance to the wind load because the outer peripheral surface is formed as a curved surface, and by itself constitutes a sophisticated appearance, so that separate members when used in civil and architectural structures such as bridges, arches, towers, etc. Even without the combination, you can get the added benefit of creating a stylish look.

In the above, the preferred embodiments of the present invention have been described by way of example, but the scope of the present invention is not limited to these specific embodiments, and may be appropriately changed within the scope described in the claims. In the embodiment shown in the drawings, each closed cross-section steel has been exemplified a configuration that is bonded to the end of the semi-circular cross-section steel, the configuration is joined to the outer surface of the semi-circular cross-section steel also belongs to the scope of the present invention.

In addition, each configuration of the above-exemplified embodiments is not limited to a specific shape, and may be combined with components not shown in each embodiment to implement various types of steel girders for bridges described in the claims.

100, 100 ', 200, 300, 400: steel girders for bridges
110, 210: first semicircular section steel
120, 220: second semicircular section steel
130, 140, 230, 240: closed section steel
150, 250: tension material

Claims (9)

Steel girders for bridges that support loads acting on the concrete slabs of bridges,
A first semicircular cross-section steel 110 and a second semicircular cross-section steel 120 having a semicircular cross section formed by cutting a steel pipe pipe having a circular cross section and extending in the longitudinal direction in half;
The reinforcement is made of a closed cross section which is not coupled to the inside, and are disposed at the upper and lower sides, respectively, with a maximum width and a compressive stress and a tensile stress in the state installed in the bridge, and are formed with the same width and the same size, respectively. The first semi-circular cross section so that the end of the first semi-circular cross section steel and the end of the second semi-circular cross section steel are welded to both sides, respectively, and protrude outward from the arc of the first semi-circular cross section steel and the second semi-circular cross section steel. A pair of closed cross-section steels (130, 140), each side of which is joined to a steel material and the second semi-circular cross-section steel;
It is configured to include, the end surface 101 is cut off from the outside by welding the both ends of the first semi-circular cross-section steel (110, 120) formed by cutting a steel pipe pipe of a circular cross section to the closed cross-section steel (130, 140) ) Is formed, and installed on the bottom side of the bottom plate concrete to support the load acting on the bottom plate concrete girder for bridges.
The method of claim 1,
The steel girder for bridges is formed to have a curvature along the longitudinal direction, the steel girder for bridges is characterized in that the bridge is formed by connecting a plurality in the longitudinal direction.
The method of claim 1,
The steel girder for bridges, characterized in that the tension section 150 is embedded in the closed section steel to introduce compression prestress into the steel girder for bridges by tensioning the tension member 150.
The method of claim 3, wherein
In the tension member installed in the closed cross-section steel (130, 140), the spacer 260 for maintaining a gap between the inner wall of the closed cross-section steel (130, 140) and the tension member 150 is installed at a longitudinal interval. Steel girder for bridges, characterized in that.
A steel girder according to any one of claims 1 to 4, which is mounted in a plurality of rows as a supporting member on a lower structure of the bridge;
A bottom plate concrete installed on an upper side of the bridge steel girder;
The bridge, characterized in that the closed section steel is formed on the upper and lower sides respectively in the direction of gravity. delete delete delete delete

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