KR101103300B1 - Steel box girder with reinforced continuous support and construction method therewith - Google Patents

Abstract

PURPOSE: A steel box girder, in which cross sectional rigidity of a connection point is improved, and a bridge construction method using the same are provided to efficiently resist the bending moment of a connection point. CONSTITUTION: A steel box girder comprises a longitudinal stiffener(400) and lower concrete(300). The longitudinal stiffener is installed between a lower flange(110) and an upper flange(130) according to the location of the bridge bearing foundation in which a steel box girder is installed. The lower concrete is formed on the bottom flange and two webs(120) while surrounding the lower part of the longitudinal stiffener. The lower concrete includes an opening around the longitudinal stiffener in order to prevent that the lower part of the longitudinal stiffener is buried inside.

Description

STEEL BOX GIRDER WITH REINFORCED CONTINUOUS SUPPORT AND CONSTRUCTION METHOD THEREWITH}

The present invention relates to a steel box girder with increased cross section stiffness of a continuous point and a bridge construction method using the same. More specifically, the steel box girder with increased cross-sectional stiffness of the continuous point portion reinforced with cross-sectional stiffness to more effectively resist the bending parental forces generated in the continuous point portion of the piers in the steel box girder and the bridge construction method using the same It is about.

Steel box girder 10 for a bridge is made of a box structure formed of a steel upper flange 13, the abdomen 12, the lower flange 11, as shown in Figure 1a, the packaging or slab concrete (top) It is bridge girder which functions as bridge upper structure by pouring 50).

Such a steel box girder 10 is constructed so as to be connected to each other between the piers or bridges (points) when constructing a bridge in a plurality of zones, that is, a continuous bridge form.

However, because the steel box girders are made of relatively thin steel sheet, the longer the extension length, the more susceptible to torsion or buckling, so that the longitudinal and lateral ribs are installed on the inner side of the steel box to reinforce them.

1A shows an example of installation of such longitudinal and lateral ribs 30 and 40.

That is, the strong box girder 10 is composed of the upper flange 13, both the abdomen 12, the lower flange 11 to be formed in the form of a box body, such an upper flange 13, both Longitudinal and transverse ribs 30 and 40 are provided on the inner side of the abdomen 12 and the lower flange 11.

First, looking at the longitudinal and horizontal ribs (30, 40) installed in the upper flange 13, the longitudinal rib 30 is to extend in the longitudinal direction in the form of a vertical plate on the bottom of the upper flange (13). As can be seen, it can be seen that a large number of spaced apart in the horizontal direction.

At this time, since the horizontal rib 40 interferes with the longitudinal rib 30, the longitudinal rib through-hole H is formed to penetrate the longitudinal rib 30, and then the longitudinal rib 30 is formed in the longitudinal rib 30. The upper flange is attached to the bottom by welding.

At this time, in order to prevent the strength loss by the space occupied by the longitudinal rib through-hole H, in the case of the horizontal rib 40, the vertical abdominal plate 41 and the horizontal flange 42 is coupled Steel of cross section is used.

Accordingly, the longitudinal and lateral ribs 30 and 40 are essentially installed in order to reinforce buckling and distortion, especially in a member in which a compressive force is generated.

Furthermore, in the case of the abdomen 12, the horizontal reinforcement 52 is installed in the longitudinal direction on the inner side, and the vertical reinforcement 51 is also installed to intersect the horizontal reinforcement 52.

Also in the case of the lower flange 11, the longitudinal ribs 30 and the lateral ribs 40 are similarly provided.

Further, the bridge slab concrete 50 is placed and cured on the upper flange 13 of the steel box girder, the slab concrete 50 and the upper flange 13 and both sides of the upper flange 13 in order to improve the synthetic capacity The upper surface of the slab shear connection member 60 will be concentrated.

In addition, in the case of the steel box girders 10 installed in the multi-span, the bending parent moment is generated in the same point portion as the upper part of the piers, and in accordance with the size of the bending parent moment and the number of installation of longitudinal ribs and transverse ribs The size and shape of the cross section is determined and installed. Since the size of the bending parent is large, the vertical diaphragm 70 is spaced in the longitudinal direction over the point, as shown in FIG. 1B.

That is, the vertical diamond frame 70, which is a steel plate reinforced with vertical and horizontal reinforcement, is installed between the upper flange 13 and the lower flange 11 of the steel box girder 10, but the vertical rib frame 70 It is installed so that the directional rib can penetrate.

At this time, the opening 80 is further installed in the vertical diamond frame 70 so that the work can pass through for maintenance and quality control of the bridge.

In addition, a bridge bearing 90 is installed on the bottom of the lower flange 11 on which the vertical diamond frame 70 is installed. Since the bridge bearing 90 directly supports the steel box girder 10, a load is applied around the bridge bearing. Since it is intended to concentrate, the vertical diamond frame 70 is usually installed above the bridge bearing 90 so as to sufficiently resist load concentration.

Furthermore, as shown in FIG. 1c, the steel box girder located at the pier (branch part) is composed of a lower concrete (B) on the upper surface of the lower flange so that the lower flange becomes a compression flange to be more effectively resisted by bending joints. In order to increase the composite capacity with the lower flange, the lower concrete is to additionally install a shear connector (stud) on the upper surface of the lower flange (11).

However, as the lower concrete (B) is formed, the bending stiffness of the point portion can be increased, but in view of the maintenance of the steel box girder, the lower concrete makes the bridge inspection impossible because the visual inspection is impossible when the steel box girder is defective. 90) There was a problem that the inspection of the bottom concrete cracks, fatigue cracking of the steel box, etc. is inconvenient.

Therefore, the present invention can cope more effectively with the bending parental force generated in the same point as the upper part of the pier of the steel box girder installed in the multi span, but also the continuous point that can easily check the fatigue cracking of the lower concrete cracks, steel box The technical problem to be solved is to provide a steel box girder with an increased cross-sectional stiffness and a bridge construction method using the same.

According to an aspect of the present invention,

In the strong box girder comprising an upper flange, both abdomen and the lower flange,

Vertical reinforcement is installed between the lower flange and the upper flange corresponding to the position of the bridge support of the bridge lower structure in which the steel box girder is installed; A lower concrete formed around the lower portion of the vertical reinforcement to have a predetermined thickness on the lower flange and both abdomen, and formed so that the opening (F) is formed around the vertical reinforcement so that the lower portion of the vertical reinforcement is not buried. As a result, the lower flange is exposed.

That is, while the lower concrete is not formed around the vertical stiffener welded portion, an inner horizontal plate having a predetermined height is provided from the upper surface of the lower flange of the steel box girder for a certain section in the longitudinal direction of the bridge around the branched portion. , High-flowing high-strength concrete is formed in the closed space consisting of the lower flange and the inner horizontal plate to suppress the cracking of the lower concrete at the point and effectively increase the bending stiffness at the point To respond,

Furthermore, the upper flange of the constant moment section is welded by being provided on the upper side of the two abdomen, whereas the upper flange of the parent moment section is installed downward from the upper part of both abdomen, and the slab concrete is poured on the enlarged section to increase the stiffness of the point. It was to cope efficiently with the tension of the continuous point.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Steel box girder according to the present invention can be provided with a more efficient increase in the rigidity of the continuous point portion can secure the economical yet structural effect can be greatly enhanced.

In addition, an opening is provided around the vertical reinforcement to prevent the bottom flange from being embedded in concrete in the continuous point part, so that it is possible to maintain and maintain the fatigue cracks in the vertical reinforcement welder, so that quality control of the steel box girder is very easy. do.

Figure 1a is a cross-sectional view of a conventional steel box girder,
1B is a cross-sectional view of a steel box girder of the conventional continuous point portion,
Figure 1c is a perspective view of the strong box of the conventional continuous point portion,
2 is a perspective view of a steel box girder of the present invention,
3a, 3b and 3c are cross-sectional views of the steel box girder of the present invention,
Figure 4a is a perspective view of the strong box located in the continuous point of the present invention,
Figure 4b is a cross-sectional view of the inner horizontal plate installation of the present invention,
5 is a perspective view of the bridge according to the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

[Steel box girder 100 of the present invention]

2 and 3A, 3B and 3C show the overall perspective and cross-sectional views A-A, B-B and C-C of the steel box girder 100 of the present invention. It is manufactured to have a certain length, which must be determined according to the span length of the bridge, so the length is not limited and can be changed.

Such steel box girders are sometimes installed in short spans, but since steel box girders are commonly used for long span bridges, they are usually manufactured to pass through bridges installed between shifts, and the part supported by the bridges is a continuous point part (D). .

In the continuous point portion (D), the bending parent moment is generated in the steel box girder, and the compression force and the lower portion of the steel box girder are generated by the bending parent moment.

In contrast, the bending moment is generated in the steel box girder at the portion other than the continuous point portion (D), and the upper portion of the steel box girder is tensile and the upper portion is compressive due to the bending positive moment.

In the present invention, this will be referred to as a particularly constant moment (E).

The present invention has a technical configuration to effectively resist the bending moment generated in the continuous point portion (D) of the steel box girder in particular, it is provided with a technical configuration that is easy to maintain the continuous point portion .

Specifically,

As shown in FIG. 2, the steel box girder 100 is manufactured by processing a steel plate as a box-shaped structure with a generally rectangular cross section.

Thus, the strong box girder 100 is manufactured to include a lower flange 110, both abdomen 120 and the upper flange 130.

At this time, the lower flange 110 is made of a steel plate extending in the longitudinal direction. In the case of the lower flange 110 is formed in the form of a flat plate in the constant moment portion (E) in the continuous point portion (D) the lower concrete 300 is formed by the inner horizontal plate 200, the vertical reinforcement (400) ) Is formed.

This will be described with reference to FIGS. 4A and 4B.

First, the inner horizontal plate 200 is located above a certain height from the lower flange 110, but both sides are installed to contact both abdomen (120).

The spacer 210 is used to maintain such a constant height. The spacer 210 is a rod-shaped member so that the bottom surface can be fixed by welding to the lower flange 110, and the upper portion from the center upper surface. The convex portion 211 protruding upward is formed to be formed.

Accordingly, the through-hole 220 is formed in the inner horizontal plate 200 so that the convex portion 211 is exposed so that the convex portion 211 of the spacer 210 is exposed by the through-hole 221. In the meantime, the upper surface surrounding the ball roll part is supported in contact with the bottom of the inner horizontal plate 200 so that the inner horizontal plate 200 can be easily set while maintaining the flatness by the spacer 210.

The inner horizontal plate 200 is installed to be completely fixed by welding to both abdomen (120).

Since the lower concrete 300 is poured into the inner space by the inner horizontal plate 200, the front and rear surfaces of the inner horizontal plate 200 are closed by the vertical finishing plate 230 so that the lower concrete does not leak.

In this case, the spacer 210 forms a bolt hole 212 at the center of the upper surface as shown in FIG. 4B and the nut in the state in which the bolt hole 212 is exposed by the through hole 221 of the inner horizontal plate 200. The inner horizontal plate 200 may be compressed to the spacer 210 by 213.

At this time, the important point is that the central portion of the inner horizontal plate 200, as shown in Figure 4a to form an opening (F) to expose the lower flange 110.

This is to form an empty space in the continuous point portion (D) to check the lower flange 110 with the naked eye.

Accordingly, it can be seen that the inner horizontal plate 200 has a vertical finish plate 230 formed around the opening (F).

The number of installation of the vertical finish plate 222 will be determined according to the opening shape.

Particularly, the opening is positioned at the center of the lower flange because the bridge support 90 is installed below the lower flange as shown in FIG.

Accordingly, the installation position of the opening may be changed somewhat in accordance with a portion vulnerable to cracking and the like in the continuous point portion, and the number of installation may be increased.

In the present invention, it is shown that one opening F is installed at the center of the lower flange 110.

Furthermore, it can be seen that the vertical reinforcement member 400 having a vertical panel shape extending upward through the opening is formed on the upper surface of the lower flange on which the bridge receiving 90 is installed.

The upper surface of the vertical reinforcement 400 is extended to contact the bottom surface of the upper flange (130).

This vertical reinforcement 400 is a vertical panel may be formed a number depending on the size of the opening. It can be seen that many are installed in parallel in the transverse direction.

Further, the lower concrete 300 is filled in the space formed by the inner horizontal plate 200, the lower flange 110, and both the abdomens 120 by the vertical finishing plates 230.

The lower concrete 300 may be filled through a filling hole (not shown) formed in the inner horizontal plate 200.

The lower concrete 300 filled therein is integrated with the lower flange and the lower abdomen by the spacers 210.

As a result, the compressive force acting on the lower flange located at the continuous branch portion (D) resists the lower flange of the steel box girder and the lower concrete integrated with the inner horizontal plate, so that the cross-section stiffness of the continuous branch portion is increased to enable effective continuous branch portion reinforcement. do.

In addition, since the lower concrete is filled inside the internal reinforcing plate, a confine effect occurs, which is very advantageous for compressive force resistance.

In addition, it is difficult to secure such cross-sectional stiffness in the opening (F) located above the bridge support (E), but in the present invention, since the vertical reinforcing material is installed in the opening (F), it is very effective to secure the cross-sectional stiffness of the continuous point portion by forming the opening heel. effective.

In addition, since the vertical reinforcing material 400 is in contact with the bottom of the upper flange directs the load from the upper flange to the bridge support side, in particular, the efficient cross-sectional design of the steel box girder is possible by the distribution of the working load.

Both abdomen 120 is a steel plate that extends upward to both sides of the lower flange, as described above, the inner horizontal plate 200 is installed at the bottom and the upper flange 130 is installed at the top.

The upper flange 130 is also a steel plate extending in the longitudinal direction in the continuous point portion (D) is installed so as to contact the bottom surface by the vertical reinforcement 400, the important point is in the continuous point portion (D) unlike the prior art The upper flange 130 to be formed is disposed at a lowered position by moving downward from the upper surface of both of the abdomen 120 is fixed to both sides by the abdomen and welding.

Therefore, the step between the upper flange 130 and the upper surface of the both abdomen 120 is reduced, whereby the placing height of the slab concrete 500 is placed on top of the upper flange is more effective in the continuous point portion.

In the continuous point portion (D), the tensile force is generated in the upper portion of the steel box girder, the tensile force is to be burdened by the upper flange, it is possible to reinforce the continuous point portion more efficiently by the thickness of the slab has a higher casting height .

Therefore, the continuous point portion (D) of the steel box girder 100 according to the present invention can be seen that it can effectively increase the cross-sectional stiffness by the lower concrete and thicker slab and improve the composite effect of the slab concrete and the upper flange For this purpose, a plurality of shear connectors are installed on the upper flange.

At this time, the upper flange 130 of the positive moment portion (E) is to be located on the upper surface of both abdomen, unlike the upper flange of the continuous branch portion for this purpose, the front flange and the rear surface of the upper flange of the continuous branch portion is extended upward and the upper portion of the central moment portion It can be seen that it is formed to have continuity with the flange.

Thus, in the steel box girder according to the present invention as shown in Figs. 3a, 3b and 3c,

Looking at the cross-sectional view of the continuous point portion (A) central portion (AA) with reference to Figure 3a, the lower concrete (110) on the upper surface of the lower concrete 300 is formed below the inner horizontal plate (200) (not shown in the gap). It can be seen that, in the opening (F) formed in the center of the lower flange 110, a vertical reinforcing material 400 is formed, the upper flange 130 is formed at a position spaced downward from the upper surface of both abdominal slab concrete (500) ) Is cast from the upper flange upper surface, the slab thickness can be seen that is formed larger than the constant moment portion (E, CC cross-section) described later.

In addition, when looking at the cross-sectional view of the continuous point portion (A) around the central portion (BB) with reference to Figure 3b, the lower concrete 300 is also formed on the lower inner horizontal plate 200 and the upper flange 130 is also the upper abdomen upper surface It can be seen that the slab concrete 500 is formed at a position spaced downward from the upper flange and the slab thickness is formed larger than the static moment portion B to be described later.

In addition, looking at the cross-sectional view of the moment of the CC (CC) with reference to Figure 3c, the upper flange 130 is formed on the upper surface of both abdomen slab concrete by the slab concrete 500 to be cast is formed smaller than the slab thickness of the continuous point portion It can be seen that.

In the case of the constant moment, the compressive force is generated in the upper part of the composite girder, and the concrete does not have to form a large thickness of the slab because the cross section stiffness is large.

[Bridge construction method using the steel box girder 100 of the present invention]

First, the steel box girder 100 described above will be manufactured in a factory, and in this case, the steel box girder as shown in FIG. 2A including the lower flange, the abdomen and the upper flange will be manufactured.

Next, the steel box girder is transported to the site, and is mounted on the bridge undercarriage structure 600 previously constructed.

The bridge substructure 600 is a bridge and a plurality of bridges 620 are constructed between the bridge 610, the bridge top is provided on the bridge top.

The steel box girder is installed on the bridge support E so that the continuous point portion D of the steel box girder 100 of the present invention passes through, so that the vertical reinforcement is positioned on the bridge support 90.

Accordingly, when the mounting of the steel box girder is completed, the slab concrete 500 is placed on the upper portion of the steel box girder to complete the final slab so that the bridge construction can be completed.

Accordingly, in the steel box girder bridge according to the present invention, the slab becomes thicker than the constant moment portion and the lower concrete confined by the inner horizontal plate resists the bending parent moment generated in the continuous point portion D. The load transmitted from the slab by the vertical stiffener can be directly induced and distributed to the bridge support and the bridge substructure.

In addition, in the constant moment portion, it resists the bending constant moment as in a conventional steel box girder.

In the steel box girder of the present invention, the installation of the longitudinal and lateral ribs is omitted, but the ribs may be installed in the positive moment to effectively compensate for the sectional stiffness.

Further, the lower concrete of the steel box girder of the present invention may be formed before mounting on the bridge lower structure first, or after mounting, thereby securing the efficiency of the mounting work by the weight of the lower concrete.

100: Steel Box Girder
110: lower flange 120: abdomen
130: upper flange
200: internal level plate
210: spacer 230: vertical finish plate
300: lower concrete
400: vertical reinforcement
500: slab concrete
600: bridge undercarriage
D: Continuous point part E: Static moment part
F: Opening department

Claims (12)

In the strong box girder comprising an upper flange, both abdomen and the lower flange,
Vertical reinforcement 400 is installed between the lower flange and the upper flange corresponding to the position of the bridge support of the bridge lower structure in which the steel box girder is installed;
A lower concrete 300 formed around the lower portion of the vertical reinforcement to form a predetermined thickness on the lower flange and both abdomen, and the opening F is formed around the vertical reinforcement so that the lower portion of the vertical reinforcement is not buried. The steel box girder with increased cross-sectional rigidity of the continuous point portion, characterized in that the lower flange is exposed by the opening so that the lower flange can be repaired or reinforced by lower concrete pouring. The method of claim 1,
The lower flange is spaced upward from the lower flange to form an inner horizontal plate 200 connected to both abdomen and both sides to form a lower concrete 300 is filled between the inner horizontal plate and the lower flange. Steel box girders with increased cross section stiffness at continuous points. The method of claim 2,
The inner horizontal plate 200 and the lower flange 110, the spacer is to be further formed on the upper surface, the spacer is a continuous member characterized in that the upper surface is in contact with the bottom of the inner horizontal plate and the bottom surface is installed in contact with the lower flange Steel box girders with increased section stiffness at points. The method of claim 3,
A protruding block is further formed in the center of the upper surface of the spacer, and a through hole is formed in the inner horizontal plate corresponding to the protruding block so that the upper surface of the spacer is in contact with the lower surface of the inner horizontal plate. Steel box girders with increased cross section stiffness at continuous points. The method of claim 3,
An additional bolt hole is formed in the center of the upper surface of the spacer, and a through hole is formed in the inner horizontal plate corresponding to the protruding block, and the upper surface of the spacer around the bolt hole is fastened by a nut fastened to the bolt hole. Steel box girder with increased cross-sectional rigidity of the continuous point portion characterized in that the horizontal plate is pressed on the bottom. 6. The method of claim 5,
Steel box girder with increased cross-sectional stiffness of the continuous point portion characterized in that the vertical finish plate 230 is further formed so that the lower concrete does not leak along the inner surface of the front and rear openings of the inner horizontal plate. The method according to any one of claims 1 to 6,
The upper flange located at the continuous point portion is set at a position spaced downward from the upper surface of both abdomen so that both sides are fixed in contact with the two abdomen, the front flange and the rear flange of the upper moment portion formed on the upper height of the upper abdomen Steel box girder with increased cross-sectional rigidity of the continuous point portion, characterized in that to be connected to each other. The lower concrete 300 is formed between the opening F and the lower flange formed around the vertical stiffener 400 so that the steel box girder of claim 1 is not embedded in the lower concrete 300 on which the vertical stiffener 400 is placed. Produced by pouring a certain thickness and curing
The steel box girder is mounted on the bridge lower structure 600 such that the vertical reinforcement of the steel box girder passes through the continuous point portion, which is the pier of the bridge lower structure.
Bridge construction method using the steel box girder with increased cross-section stiffness of the continuous point portion comprising the step of placing slab concrete on the upper flange of the steel box girder. The method of claim 8,
The spacer is further formed on the upper surface of the inner horizontal plate and the lower flange, wherein the spacer is a rod member having an upper surface in contact with a lower surface of the inner horizontal plate and a lower surface of the lower flange contacting the lower flange. Bridge construction method using steel box girder. The method of claim 9,
The lower flange is spaced upward from the lower flange to form an inner horizontal plate 200 connected to both abdomen and both sides to form a lower concrete 300 is filled between the inner horizontal plate and the lower flange. Bridge construction method using steel box girder with increased cross section stiffness of continuous point. In manufacturing the steel box girder of claim 1, the steel box girder is first mounted on the bridge substructure 600 so that the vertical reinforcement of the steel box girder passes through the continuous point portion of the bridge substructure without placing the lower concrete.
In order to prevent the vertical reinforcement member 400 from being embedded in the lower concrete 300, the lower concrete 300 is poured and cured by a predetermined thickness between the opening F and the lower flange formed around the vertical reinforcement member 400, both abdomens,
Bridge construction method using the steel box girder with increased cross-section stiffness of the continuous point portion comprising the step of placing slab concrete on the upper flange of the steel box girder. 12. The method of claim 11,
The lower flange is spaced upward from the lower flange to form an inner horizontal plate 200 connected to both abdomen and both sides to form a lower concrete 300 is filled between the inner horizontal plate and the lower flange. Bridge construction method using steel box girder with increased cross section stiffness of continuous point.

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