KR101122958B1 - Steel box girder with reinforced rigidity and method for constructing bridge thereof - Google Patents

Abstract

PURPOSE: A steel-box girder with increased rigidity and a bridge constructing method using the same are provided to minimize or remove fastening members since a lower flange, web and an upper flange are formed in a panel shape. CONSTITUTION: A steel-box girder with increased rigidity comprises a lower flange(110), webs(120), an upper flange(130), and a shear connecting unit(140). The lower flange is formed in a panel shape, is located on the top of pier and supports a steel-box girder. The web is formed in a panel shape and is longitudinally installed on the lower flange to have a side shape of π. The upper flange is formed in a panel shape and both ends of the upper flange are installed in the web so that facing webs are connected. The shear connecting unit is buried in slab concrete. The shear connecting unit fastens the steel-box girder to the slab concrete.

Description

Steel box girder with reinforced rigidity and method for constructing bridge

The present invention relates to a bridge using a steel box girder, and more particularly, a shear connection portion is formed in the steel box girder, and a steel box girder having an increased cross-sectional rigidity for constructing a bridge using the steel box girder and using the same It is about bridge construction method.

In general, girders (Girder) is a structural member for the bridge that supports the weight of the slab and the load acting on the slab, and has a function of transferring the acting load to the pillar or piers that are the bridge substructure.

According to the recent road bridge and tunnel status document (Ministry of Land, Transport and Maritime Affairs, 2008), the total length of bridges built on Korean highways is 904,905m, and the river box girder bridge (Gangsanghyeon bridge) accounts for 34.4%. In addition, the total length of the steel box girder bridge on other national roads and roads totals approximately 721,058m. Since the steel box girders are mainly manufactured using thin steel sheets having large size, the flange part or the abdominal plate which are compressed may be broken by local buckling. Therefore, it is very important in the design of the steel box girder to prevent local buckling that may occur in the thin plate element before reaching the bending strength that the steel box girder can exert.

As shown in FIG. 1, the conventional steel box girder 10 is manufactured by assembling the lower flange part 11, both sides of the abdomen 12, and the upper flange part 13.

The lower flange portion 11 is formed of a double bottom plate member, and the upper bottom plate member 11a and the bottom plate member 11b are installed to form a hollow part S spaced apart from each other.

The abdomen 12 is a member that connects the side surfaces of the lower flange portion 11 and the upper flange portion 13, the lower portion is respectively installed at the four corners of the lower flange portion 11, the upper flange portion ( 13) is installed.

The upper flange portion 13 is a member on which the slab formwork plate 14 for placing and curing the slab (not shown) is seated. The upper flange portion 13 is disposed on the upper part of the abdomen 12 so that both edge portions of the slab formwork plate 14 are seated. Installed.

However, the abdomen 12, the upper flange portion 13 is made of an L-shaped steel member, and the lower flange portion 11 is made of a double bottom member, so that a number of separate members for mutual fastening and rigid reinforcement As required and the number of working hours increased, the working time became long.

In addition, although the installation of the upper bottom plate member 11a and the lower bottom plate member 11b is for increasing the rigidity of the lower flange part 13, it was independent of the space | interval, ie, the height variation of the hollow part S, mutually.

In addition, in order to reinforce the stiffness of the abdomen 12, an additional member is required to further install the abdominal inclination part steel member 16, thereby increasing the difficulty of working.

The present invention has been made to solve the above problems, the lower flange portion, the abdomen and the upper flange portion is formed in a panel shape, the member for fastening is minimized or eliminated, the rigid reinforcement member is unnecessary, the work maneuver and work It is an object of the present invention to provide a steel box girder with increased cross-sectional rigidity and a bridge construction method using the same.

In addition, it is another object to provide a steel box girders and a bridge construction method using the same by increasing the cross-section stiffness to be reused by the conventional steel box girders by being able to additionally install the shear connection member to the steel box girders.

In addition, another object of the present invention is to provide a steel box girder and a bridge construction method using the same, the cross-sectional stiffness of which the thickness of the flange portion can be adjusted according to the installation position of the upper flange portion.

In addition, another object of the present invention is to provide a steel box girder with an increased cross-sectional stiffness to allow slab concrete to be placed on an upper surface of the steel box girder and a bridge construction method using the same.

Steel box girders according to the present invention for achieving the above object, in the steel box girders, panel-shaped lower flange; A panel-shaped abdomen installed in the longitudinal direction so as to have one side shape of a "ㅛ" shape in the lower flange portion; An upper flange portion of the panel shape installed to connect the oppositely positioned abdomen; And a perforbond type panel-shaped perforated shear connecting portion provided on an extension line of the abdomen, and a plurality of through holes are formed in the longitudinal direction in the perforating shear connecting portion.

Here, the height (h) of the pore shear connector is calculated by calculating the cross-sectional stiffness (EI) having a certain range through the cross-sectional secondary moment formula of Equation 1 below, and according to the calculated height (h) of the pore shear connector The flange portion is installed at a certain position.

[Equation 1]

Where I is the cross-sectional secondary moment, b is the base length, and h is the height. In addition, E in the cross-sectional rigidity (EI) is a constant depending on the material.

In addition, the height h of the hole shear connecting portion has a ratio of H: h = 1: 0.03 to 0.2 compared to the height H from the lower flange portion to the upper flange portion.

In addition, the air hole shear connecting portion is formed integrally with the abdomen, and both ends of the upper flange portion is formed by being spaced apart by a predetermined interval downward from the upper end of the abdomen, and has a height from the position where the upper flange portion is installed in the abdomen to the upper end.

A reinforcement having a wider width than the width of the upper surface of the hole shear connector is installed on the upper surface of the hole shear connector.

As an embodiment of the hole shear connecting portion, the cross section is “T” shaped, and the bottom surface is installed to be positioned at the end of the upper flange portion while being fixed in the “T” shape.

In addition, in another embodiment of the hole shear connecting portion is a cross-section "b" shaped, is fixed in the "b" shape, the lower surface is located at the end of the upper flange portion, the refracted upper portion is installed outward.

On the other hand, the bridge construction method using the steel box girder thus produced, the step of installing the abdomen in the longitudinal direction so as to have a one-sided shape of the "부 에" type in each of the lower flanges arranged at regular intervals (S10); An upper flange portion is installed to connect the oppositely positioned abdominal portions to form a hole shear connecting portion (S20); Forming a plurality of through holes in the longitudinal direction in the hole shear connecting portion (S30); Forming step is installed so that the pore shear connection is received (S40); And the step of curing the slab concrete is poured into the formwork (S50).

Here, in the step (S40) in which the formwork is installed, the inner bottom surface of the formwork is installed to match the upper surface of the upper flange portion.

In addition, in the step of pouring and curing (S40), the slab concrete is poured on the upper surface of the inner bottom surface and the upper flange of the formwork, and is poured so that the through-holes are filled as the hole transmission connecting portion is embedded.

As described above, according to the present invention, the lower flange portion, the abdomen, and the upper flange portion are replaced by the panel shape in the conventional section steel, so that the fasteners and folding members for the conventional fastening are removed, and thus the labor time is reduced. This is reduced, the work cost is reduced.

In addition, the thickness of the flange portion and the abdomen is made thinner by selecting the height of the shear connection member by considering the thickness of the flange portion and the abdomen within the allowable range of the cross section secondary moment of the steel box girder required by the installation location and the working environment. The material cost of the steel box girders can be reduced. In this case, since the flange portion and the abdomen are panel-shaped, and the shear connecting member also has a certain length, the thickness of the flange portion and the abdomen may be further thinned.

In addition, the thickness of the flange and the abdomen can be determined according to the height of the shear connection member in a state where the cross-section secondary moment required for the steel box girders is always satisfied according to the work site and the construction. There is.

In addition, the upper flange is provided so as to connect the oppositely positioned abdomen, the upper flange portion from the upper end of the abdomen is a shear connecting member, that is, the upper part of the abdomen is a shear connecting member, more robust than when separately installed, There is an effect that the work maneuver is reduced, and the convenience of work is improved.

In addition, a separate shear connection member can be installed and used in a conventional substantially rectangular steel box girder, so that the already manufactured steel box girder can be reused, and the manufacturing cost at this time is very inexpensive and can be easily applied anywhere. There is.

In addition, since the slab concrete is filled in a plurality of fastening holes formed in the shear connection member while the shear connection member is embedded in the slab concrete, there is an effect of maximizing the coupling force between the shear connection member and the slab concrete.

In addition, since the slab concrete is poured on the upper surface of the upper flange portion, the upper surface of the upper flange portion to replace a part of the entire inner bottom surface of the conventional formwork, which has the effect of reducing the manufacturing cost of the formwork.

1 is a perspective view schematically showing a conventional steel box girder.
2 is a perspective view schematically showing a steel box girder with increased cross-sectional rigidity in accordance with a preferred embodiment of the present invention.
3 is a perspective view illustrating a modification of FIG. 2.
4 and 5 are perspective views showing the first and second embodiments of the steel box girder shown in FIG.
FIG. 6A is a partially separated perspective view of the bridge constructed using the steel box girder of FIG. 2. FIG.
FIG. 6B is a partial side cross-sectional view of the bridge shown in FIG. 6A.
FIG. 7 is a perspective view illustrating a construction process of a bridge using the steel box girder of FIG. 2.
8 is a flowchart of FIG. 7.

Hereinafter, a steel box girder with increased cross-sectional rigidity according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration>

2 is a perspective view schematically showing a steel box girder with increased cross-sectional rigidity in accordance with a preferred embodiment of the present invention, Figure 3 is a perspective view showing a modified example of FIG.

First, as shown in FIG. 2, the steel box girder 100 according to the present invention includes a lower flange part 110, an abdomen 120, an upper flange part 130, and a pore shear connecting part 140. .

The lower flange part 110 has a panel shape and is positioned on an upper surface of a pier (not shown) to support the steel box girder 100. At this time, since the length (b) of the lower flange portion 110 is closely related to the cross-sectional secondary moment (I) described later, it is seriously considered along with the height of the perforated shear connecting member 140.

The abdomen 120 has a panel shape, and is installed on the lower flange 110 so as to face each other at right angles so as to have one side shape of a substantially "ㅛ" shape. Here, the abdomen 120 is installed at a position moved inward by a predetermined length from the end of the lower flange 110. Of course, the abdomen 120 may be installed to match the end of the lower flange 110.

The upper flange portion 130 has a panel shape, and both ends thereof are installed inside the abdomen 120 so that the mutually opposing abdomen 120 is connected to each other. Here, both ends of the upper flange portion 130 are located and fixed to the mutually opposite surfaces of the abdomen 120, respectively. Of course, the upper flange 130 is located on the upper surface of the abdomen 120 may be fastened to the abdomen 120 in the same size and shape as the lower flange 110. The installation height H of the upper flange portion 130 is closely related to the cross-sectional secondary moment I described later and should be carefully considered.

The pore shear connecting portion 140 is a portion embedded in the slab concrete 200, as shown in Figure 6a, a portion for fastening the steel box girder 100 and the slab concrete 200, perforbond rather than the conventional stud method Method is adopted. Therefore, the upper flange portion 130 is formed long in the longitudinal direction, a plurality of through holes 141 are formed along the length. The through hole 141 is subsequently filled by the slab concrete 200 is formed to improve the fastening force of the perforated shear connecting portion 140, that is, the steel box girder 100 and the slab concrete 200. At this time, the size of the long diameter of the through hole 141 and the size of the short diameter, the shortest length to the end of the through hole 141 and the hole shear connecting portion 140, the mutual length between the through hole 141, etc. In consideration of this, it is formed to prevent breakage for each part of the hole shear connecting portion 140 by the external force within a certain range. In addition, as the number of the through holes 141 increases, the amount of filling the slab concrete 200 increases, so that the tightening force increases, but as the gap between the through holes 141 decreases, the through holes 141 of the perforated shear connecting portion 140. Since the portion between the) can be easily broken, the number of through holes 141 and the distance between the through holes 141 are considered.

A preferred embodiment of such a hole shear connecting portion 140, as shown in Figure 2, the upper part of the abdomen 120 is a hole shear connecting portion 140, the upper flange portion 130 on the opposite inner surface of the abdomen 120 Both ends of the are respectively fastened. In addition, as shown in FIG. 3, a substantially rectangular reinforcing member 142 is added to the upper surface of the hole shear connecting portion 140. At this time, the width of the reinforcing material 142 is formed wider than the width of the hole shear connecting portion 140. Therefore, the cross-sectional secondary moment (I) value in the case where the stiffener 142 is installed is formed higher than when the stiffener 142 is not installed, the upper flange 130, the lower flange 110 and the abdomen accordingly The thickness of 120 can be reduced.

<Production>

Hereinafter will be described with respect to the pore shear connection for the manufacture of the steel box girder according to the present invention.

Referring to the process of manufacturing the steel box girder 100 of the bridge construction process in Figure 7, the steel box girder 100 of Figure 2 has a pair of abdomen 120 in the lower flange portion 110 " They are installed so as to face each other vertically to have one side shape of the ㅛ "type. In this case, welding may be used or a separate 'b' shaped clamp may be used to install the bolt or screw. Of course, considering the buckling applied to the steel box girder 100 after the bridge is installed, the welding is strongly attached to the entire contact surface of the lower flange 110 and the abdomen 120 is preferred.

Next, the upper flange 130 is installed at a position spaced downward from the upper end of the abdomen 120 by a predetermined interval. At this time, both ends of the upper flange portion 130 is provided on the mutually opposite surfaces of the abdomen (120). Wherein the coupling between the upper flange portion 130 and the abdomen 120 is preferably welded, it may be made through the bracket and bolt or screw as necessary.

When the hole shear connecting portion 140 is formed as described above, a plurality of through holes 141 having a predetermined size in the longitudinal direction are formed in the hole shear connecting portion 140. Later, the slab concrete 200 is filled in the through hole 141 to maximize the bonding force of the slab concrete 200 of the perforated shear connecting portion 140.

On the other hand, the height h of the pore shear connecting portion 140 is selected in consideration of the cross-section secondary moment (I) required for the steel box girder 100, the cross-sectional secondary moment (I) is the following [Equation 1] Is the same as

Where b is the length of the lower flange and h is the height of the pore shear connector. 3 is the height from the lower flange part to the upper flange part.

Therefore, the value of the cross-section secondary moment (I) is greatly affected by the height (h) of the hole shear connecting portion 140, which also has a great influence on the cross-sectional rigidity (EI). That is, as the height (h) of the pore shear connecting portion 140 is increased, it is affected by three times the variable length. Of course, the higher the height (h) of the hole shear connecting portion 140, the value of the cross-section secondary moment (I) will increase, but the depth that the hole shear connecting portion 140 is embedded in the slab concrete (200) is deepened slab The thickness of the concrete 200 is increased. Therefore, the height h of the pore shear connecting portion 140 should consider the thickness of the slab concrete 200 as well as the base length. Accordingly, the height h of the air hole shear connecting portion 140 with respect to the height H from the lower flange portion 110 to the upper flange portion 130 is preferably about 1: 0.03 to 0.2. Here, the cross-sectional secondary moment (I) is the cross-sectional secondary moment calculated through the base length (b) and the height (H) and the cross-sectional secondary moment calculated through the base length (b) and height (h) You get Of course, the cross-sectional secondary moments for each part can be obtained by subtracting the empty space from the total space.

In addition, through this cross-sectional secondary moment (I) ultimately to obtain the cross-sectional rigidity (EI) of the steel box girders (100). Since E is a constant depending on the material, the cross-sectional stiffness (EI) has a large change in the value of the cross-sectional secondary moment (I). At this time, when manufacturing the steel box girder 100, the length, width, size, etc. of the bridge is considered in consideration of the range of the cross-sectional rigidity (EI) that the steel box girder 100 should have, this cross-sectional rigidity (EI) The cross-sectional secondary moment I is determined to exist within this constant range. In addition, when the cross-sectional secondary moment (I) is determined in a predetermined range, the height (h) of the pore shear connecting portion 140 is determined. Here, the thickness of the upper flange portion 130, the lower flange portion 110 and the abdomen 120 may be changed in accordance with the change in the height (h) of the hole shear connecting portion 140. Therefore, in order to reduce the manufacturing cost of the steel box girder 100, when the height h of the air hole shear connecting portion 140 is increased, the thickness of the upper flange portion 130, the lower flange portion 110 and the abdomen 120 It can be actively utilized that can be reduced.

In addition, in the case of FIG. 3, the cross-section secondary moment I is calculated through the cross-sectional secondary moment I, and thus the upper flange portion 130 and the lower flange portion are correspondingly higher than those of FIG. 2. The thickness of the 110 and the abdomen 120 can be reduced.

<Examples>

4 and 5 are perspective views showing the first and second embodiments of the steel box girder shown in FIG. 4 and 5 illustrate an embodiment in which the air hole shear connection unit according to the present invention is installed in a substantially rectangular steel box girder that is already manufactured.

5, the upper flange 130, the lower flange 110, and the abdomen 120 are mutually coupled to each other in a substantially rectangular shape, and approximately "T" shapes at both ends of the upper surface of the upper flange 130, respectively. The first auxiliary eutectic shear connecting portion (140a) is installed. At this time, the first auxiliary eutectic shear connecting portion 140a is welded by aligning the bottom surface of the upper surface end of the upper flange portion 130 at the “T” character at the end. Therefore, one side of the wings above the first auxiliary eutectic shear connecting portion 140a is positioned outside the extension range of the abdomen 120. Of course, a separate bolt or screw coupling is also possible in addition to the welding joint. The secondary moment (I) value of the cross section is further increased by the arrangement of the first auxiliary eutectic shear connecting portion 140a. The plurality of through holes 141 are formed in the lengthwise direction of the first auxiliary oil-tight connecting portion 140a. Of course, the upper flange portion 130, the lower flange portion 110, and the abdomen 120 is a panel shape. Here, T-shaped steel may be used for the first auxiliary eutectic shear connecting portion 140a, or may be used by cutting an I shape.

In addition, Figure 5 is a substantially rectangular shape of the upper flange portion 130, the lower flange portion 110 and the abdomen 120 are mutually coupled, each of the approximately "a" shaped on both ends of the upper surface of the upper flange portion 130 The second auxiliary oil pore shear connecting portion 140b is installed. At this time, the second auxiliary eutectic shear connecting portion 140b is disposed symmetrically with the upper bent portion facing outward, the lower surface is aligned in the end and welded. Therefore, the bent portion of the upper portion of the second auxiliary eutectic shear connecting portion 140b is located outside the extension range of the abdomen 120. The second secondary moment (I) value of the cross section is further increased due to the arrangement of the second auxiliary eutectic shear connecting portion 140b. A plurality of through holes 141 are formed in the lengthwise direction of the second auxiliary oil-tight connecting portion 140b thus coupled. In addition, the upper flange portion 130, the lower flange portion 110, and the abdomen 120 is a panel shape.

Herein, the heights of the first auxiliary eutectic shear connecting portion 140a and the second auxiliary eutectic shear connecting portion 140b are set according to the cross-sectional secondary moment (I) value, and the height is about 1: 0.03 to 0.2 relative to the remaining height. Is formed in proportion.

<Bridge construction method>

FIG. 6A is a partially separated perspective view of the bridge constructed using the steel box girder of FIG. 2, FIG. 6B is a partial side cross-sectional view of the bridge shown in FIG. 6A, and FIG. 7 is a construction of the bridge using the steel box girder of FIG. 2. Process is a perspective view shown, Figure 8 is a flow chart of FIG.

First, the lower flange portion 110 is installed in each pier continuously arranged, and the abdomen 120 is vertically installed at the lower flange portion 110 so as to have one side shape of a substantially "대략" type (S10).

Next, both ends of the upper flange portion 130 is installed on the inner side surfaces of the pair of abdominal portions 120 that are opposed to each other so that the air hole shear connecting portion 140 is formed (S20). At this time, since the height (h) of the air hole shear connecting portion 140 is changed according to the position where the upper flange portion 130 is installed, the upper flange portion 130 has to be secured according to the construction environment. The location is determined according to the value of the installation.

Next, a plurality of through-holes 141 in the longitudinal direction in the hole shear connecting portion 140 is drilled (S30). Here, when the upper flange portion 130 is installed, the through hole 141 is drilled by determining the number and size according to the height and length of the air hole shear connecting portion 140.

Next, the formwork 210 is installed in the completed steel box girder 100 (S40). Here, the formwork 210 is wider than the width of the steel box girder 100, as shown in Figure 6a and 7, is installed to include at least two steel box girder (100). In addition, the inner bottom surface of the formwork 210 is formed in the empty space between the steel box girder 100 and the empty space of a predetermined length outside the abdomen 120 of the steel box girder 100. That is, the bottom surface is formed at a portion of the inner bottom surface of the formwork 210 in which the slab concrete 200 is poured except for the top surface of the upper flange portion 130. At this time, the inner bottom surface of the formwork 210 is installed to form the same plane as the upper surface of the upper flange portion 130. Here, the die 210 may be fixed by a separate fixing member (not shown) fixed to the outward side of the abdomen 120.

Next, after the slab concrete 200 is poured on the upper surface of the formwork 210 and the upper flange portion 130 is cured (S50). As shown in Figure 6b, the slab concrete 200 is poured from the top height of the upper flange portion 130 to the height to embed the hole shear connecting portion 140, the poured slab concrete 200 according to the construction environment It will change, but it has a height of approximately 24cm to 27cm.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. It is therefore to be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100 ... gang box girder
110 ... bottom flange
120 ... abdomen
130 ... upper flange
140.Perforated shear connector
141 ... through hole
142 Reinforcements
200 ... slab concrete.

Claims (10)

In the steel box girder 100,
A lower flange part 110 having a panel shape;
A panel-shaped abdomen 120 installed in the longitudinal direction so as to have one side shape of a “ㅛ” type in the lower flange 110;
An upper flange portion 130 having a panel shape installed to connect the abdomen 120 oppositely positioned; And
Perforbond type and panel-shaped hole-porous shear connecting portion 140 installed on the extension line of the abdomen 120;
Steel box girders with increased cross-sectional stiffness, characterized in that a plurality of through-holes 141 are formed in the longitudinal direction in the hole shear connecting portion 140. The method of claim 1,
The height h of the pore shear connector 140 is calculated by calculating the cross-sectional stiffness (EI) having a predetermined range through the cross-sectional second moment formula of Equation 1 below, and the calculated height of the pore shear connector 140 According to (h), the steel box girders with increased cross-sectional rigidity, characterized in that the upper flange 130 is installed at a predetermined position.
[Formula 1]

Where I is the cross-sectional secondary moment, b is the base length, h is the height and E is the constant depending on the material. The method of claim 2,
The height h of the air hole shear connecting portion 140 has a ratio of H: h = 1: 0.03 to 0.2 compared to the height H of the lower flange portion 110 to the upper flange portion 130. Steel box girders with increased cross-sectional rigidity, characterized in that. The method of claim 1,
The air hole shear connecting portion 140 is integrally formed with the abdomen 120, and both ends of the upper flange portion 130 is formed by being spaced apart at a predetermined interval downward from the upper end of the abdomen 120, the abdomen 120 Steel box girder with increased cross-sectional rigidity, characterized in that has a height from the upper flange portion 130 to the upper end in the installed position. The method of claim 4, wherein
Steel box with an increased cross-sectional stiffness, characterized in that the reinforcing member 142 having a wider than the width of the upper surface of the porous hole connecting portion 140 and the upper surface of the porous hole connecting portion 140 is installed in the panel shape of the rectangular cross section Girder. The method of claim 1,
The perforated shear connecting portion 140 is a T-shaped steel cross section, the steel box with an increased cross-sectional stiffness, characterized in that the lower surface is installed so as to be positioned at the end of the upper surface of the upper flange portion 130 while being fixed in the "T" shape Girder. The method of claim 1,
The perforated shear connecting portion 140 is a cross section of the b-shaped steel, is fixed in the form of "b", characterized in that the lower surface is located at the end of the upper flange portion 130, the refracted upper portion is installed outwardly Steel box girders with increased cross stiffness. In the method of constructing a bridge using the steel box girders of any one of claims 1 to 8,
A step (S10) in which the abdomen 120 is installed in the longitudinal direction so as to have one side shape of the “ㅛ” type in each of the lower flange parts 110 disposed at regular intervals;
An upper flange portion 130 is installed to connect the abdominal portions 120 opposed to each other, and a pore shear connecting portion 140 is formed (S20);
Forming a plurality of through holes 141 in the longitudinal direction in the hole shear connecting portion 140 (S30);
A step (S40) in which the formwork 210 is installed to accommodate the hole shear connecting portion 140; And
Bridge construction method using a steel box girder with increased cross-sectional stiffness, characterized in that the step (S50) is poured into the formwork to the slab concrete 200 is cured. The method of claim 8,
The steel box girder with increased cross-sectional rigidity, characterized in that the inner bottom surface of the formwork 210 is installed so as to match the upper surface of the upper flange portion 130 in the step (S40) is installed the formwork (210) Bridge construction method 10. The method of claim 9,
In the pouring and curing step (S40), the slab concrete 200 is placed on the inner bottom surface of the formwork 210 and the upper surface of the upper flange portion 130, while the perforated shear connecting portion 140 is embedded Bridge construction method using a steel box girder with increased cross-sectional rigidity, characterized in that the through-hole 141 is filled to fill.

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