KR101888895B1 - Steel box girder manufacturing method using load transfer member - Google Patents

Abstract

According to an embodiment of the present invention, a method for manufacturing an opening form steel girder with improved buckling performance by using a circular steel pipe load transition material comprises the steps of: manufacturing a pair of upper members (10); installing a lower flange (20) to be continuous in a longitudinal direction, and installing a pair of upper members (10) on a lower flange (20); primarily coupling a load transfer material (30) on an upper side of a vertical reinforcement member (13) by a bolt (39); welding a lower end of a web plate (11) to a lower flange (20); installing a horizontal bracing (40); releasing tensile force (PM) from the load transfer material (30) and applying tensile force (PM′) corresponding to a conductive moment (M) on the horizontal bracing (40); secondarily coupling the load transfer material (30) to the upper side of the vertical reinforcement member (13); and completing an intermediate diaphragm. The compression resistance performance can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing an open-form steel girder having improved buckling performance by using a circular steel pipe load transfer material.

The present invention relates to a method of making an opening-form steel girder with improved buckling performance using a circular steel pipe load transfer material, and more particularly, And the buckling performance is improved by using the round steel pipe load transfer material which can secure the safety against buckling during the construction by improving the torsional resistance performance of the intermediate diaphragm. .

In the construction of domestic steel bridge, the closed box steel girder is a representative type of bridge that is commonly applied in curved bridge as well as straight bridge between large and large bridges because of its high strength and high torsional rigidity. However, the closed box steel girder has a problem that the upper flange function of the girder is overlapped with the bottom plate and the efficiency is inferior, and various kinds of reinforcement materials for maintaining the box-shaped cross section are excessive,

 In order to solve the problem, an opening form steel girder has been developed which minimizes the upper flange section in the closed box steel girder and replaces the function of the upper flange in the bottom plate to improve the structural efficiency and economical efficiency.

Unlike a conventional closed box steel girder, an opening-trapezoidal steel girder is an open-ended upper flange, and a buckle plate is a trapezoidal steel girder.

1 is a perspective view of a conventional open-form steel girder.

1, the opening-type steel girder comprises a lower flange, a pair of upper flanges disposed horizontally at the upper end of the upper flange, a pair of upper flanges disposed at the upper end of the upper flange, An intermediate diaphragm connecting the pair of baffle plates, and a horizontal bracing connecting the upper flange diagonally and vertically.

Since the opening-form steel girder is smaller in the amount of steel than the closed-box steel girder and has a simple member structure, it is easy to manufacture and requires a small production cost. Therefore, bridges utilizing an opening-form steel girder are being actively constructed in the United States and Europe, The market is gradually expanding.

Despite these advantages, however, the open-form steel girder is composed of a thin-walled open section, so that the bottom plate concrete is damaged by twisting and twisting in the manufacturing, transport, It is easy to apply in Korea conservatively.

Therefore, an opening-type steel girder must contain horizontal bracing and an intermediate diaphragm inside the steel girder to prevent damage to the steel girder due to twisting and warping.

In this case, horizontal bracing increases the buckling strength of the open-form steel girder by restraining the spreading of the upper flange during construction and restraining the transverse displacement of the upper flange so as to form an imaginary closed end face shape that increases the torsional rigidity of the opening- So that both upper flanges are connected in the form of trusses.

In addition, the intermediate diaphragm is installed in the form of a K-frame connecting the baffle plates at regular intervals in the cross section to suppress distortion of the opening form steel girder.

These horizontal bracing and intermediate diaphragms are usually spaced 3-5 m apart in the cross-section of the open-form steel girder using the off-the-shelf product a. Or C. T. structural tees to reduce the amount of steel and simplify fabrication. When the horizontal bracing and middle diaphragm are installed closely, the probability of damaging the opening form girder is significantly lowered due to twisting and twisting. However, since the development purpose of the opening form girder is to improve the economical efficiency compared with the closed box girder, safety is secured It is a design practice to arrange them as wide as possible.

The accident during construction of the opening form steel girder is more frequent than that of the closed box girder. As mentioned above, as it is composed of the open end of the thin plate, it is easy to be damaged by twisting and twisting in the conveying and bottom plate concrete casting process. In order to prevent this, horizontal bracing and middle diaphragm installed, Respectively.

FIG. 2A is a photograph of a buckling of a horizontal bracing in a conventional opening type steel girder, and FIG. 2B is a photograph of a conventional opening type steel girder in which a horizontal member of an intermediate diaphragm is twisted and an oblique member is buckled.

2a, the horizontal bracing should act as a compressive and tensile material between the upper flanges of both openings to prevent transverse torsional buckling of the open-form steel girder. In Fig. 2a, the horizontal bracing is insufficient in compression resistance, Buckling occurred in buckled and open form steel girders.

2b, the middle diaphragm is connected to a pair of baffles by a horizontal member and a workpiece in order to suppress the distortion of the opening-shaped steel girder. However, since the compression resistance and the torsional rigidity are insufficient, Buckling occurred and buckling occurred in the opening type girder.

Therefore, it is possible to improve the compression resistance performance while using the ready-made a section steel or CT section steel with the horizontal bracing in the existing open-form steel girder and to improve the torsional resistance performance even with the small cross section instead of the conventional steel section or CT section steel as the intermediate diaphragm. It is necessary to select a specific cross section that can be used to secure the buckling during construction.

As a background of the present invention, Patent Document No. 2009-0066560 "Steel Box Girders" (Patent Document 1) is known. In the background art, a steel box girder having a flange welded to both sides of a bottom plate and attached to an upper end of the side plate, has a structure in which both side portions of the bottom plate connected to the side plates on both sides And a cable bracing which is connected to both the side portions of the bottom plate and the upper ends of the side plates while being crossed, wherein the cable bracing is detachably provided on the both side portions of the bottom plate and the top portions of the side plates. Steel box girder '.

However, the background technique also has a problem in that the tearing of the horizontal material and the buckling of the workpiece occur due to the lack of the compression resistance and the torsional stiffness, and buckling occurs in the opening type steel girder.

Patent Publication No. 2009-0066560 "Steel box girder"

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to improve the compression resistance performance by using a ready-made a section steel or CT section steel with horizontal bracing in an opening- It is an object of the present invention to provide a method of manufacturing an opening forming steel girder which can secure a safety against buckling during installation by selecting a specific cross section that can improve the torsional resistance performance even with a small cross section.

It is also an object of the present invention to provide a method of manufacturing an opening-form steel girder in which the procedure is simple and little cost is incurred in improving the compression resistance performance of the horizontal bracing.

(A) a pair of upper flanges welded to the upper end of the bumper plate, a pair of upper flanges welded to the upper end of the bumper plate and welded to the bumper plate at regular intervals in the throttle direction A pair of upper members composed of vertical stiffeners to be formed; (b) providing a lower flange so as to be continuous in the throttling direction, and installing a pair of upper members on the lower flange; (c) connecting the vertical stiffener and the vertical stiffener in the horizontal direction within the assembly center distance Ls while maintaining the center spacing of the upper ends of the pair of the baffle plates at the assembly center distance Ls smaller than the design center distance L by a predetermined interval A first step of fastening a load transfer material to the upper side of the vertical stiffener with a bolt; (d) welding the lower end of the bimodal plate to the lower flange in a state of bearing a tensile force (P _M ) corresponding to a moment of conduction (M) to which the load transferring aspheric member is intended to fall out; (e) installing a horizontal bracing between the load transfer material and the load transfer material so as to connect the upper flanges on both sides in the oblique direction of the same height; (f) disassembling the bolts connecting the vertical stiffener and the load transferring material to release the tensile force (P _M ) to the load transfer material and to bear the tensile force (P _M ') corresponding to the transfer moment (M) to the horizontal bracing; (g) secondarily fastening the load transfer material to the upper side of the vertical stiffener with bolts; (h) completing the intermediate diaphragm by installing a workpiece that connects the central portion of the load transfer material and the lower end of the vertical stiffener to some or all of the load transfer material, and The present invention provides a method of manufacturing an opening-form steel girder with improved buckling performance using ash.

In addition, in step (a), the vertical stiffener is formed by passing a bolt hole through the vertical stiffener at a position where the bolt hole is engaged with the load transfer material, and the diameter dh of the bolt hole is formed to be larger than the diameter db of the bolt by a predetermined size The present invention provides a method of manufacturing an opening-form steel girder in which buckling performance is improved by using a circular steel pipe load transfer material.

Further, in the step (c), the load transfer material is formed by using a round steel pipe load transfer material characterized in that a circular steel pipe having a predetermined length and a connecting rod composed of a plate material are formed at both ends of the circular steel pipe, To provide a method of manufacturing an opening-form steel girder with improved buckling performance.

In addition, in step (c), the connecting rod is formed with a connecting hole in the vertical connecting plate and the vertical connecting plate, and is coupled to the vertical stiffener. And to provide a manufacturing method.

In addition, in step (c), an intermediate plate is further provided between the circular steel pipe and the vertical connecting plate, and the buckling performance is improved by using the round steel pipe load transfer material. I want to.

In addition, in step (c), the connecting block is horizontally formed to increase the rigidity of the vertical connecting plate, and a horizontal connecting plate is formed to connect the vertical connecting plate and the intermediate plate. To provide a method of manufacturing an opening-form steel girder with improved performance.

In step (c), the diameter of the bolt hole formed in the vertical stiffener (dh (m)) is calculated considering the interval displacement amount delta where the assembly center distance Ls is increased to the design center distance L due to the conduction moment M. The present invention is to provide a method of manufacturing an opening-form steel girder in which a buckling performance is improved by using a circular steel pipe load transfer material having a width (w, w ') that is larger than a predetermined size.

In the step (c), the connecting hole is formed on both the connecting rods formed on both ends of the load transferring material on the basis of the primary fastening, and the diameter dh of the bolt hole formed on the upper end of the vertical stiffening member is half And a width (w) that is the sum of the width and the width of the opening. The present invention provides a method of manufacturing an opening-form steel girder with improved buckling performance using a circular steel pipe load transfer material.

In the step (c), the connecting hole has a width corresponding to the diameter (db) of the bolt hole formed at the upper end of the vertical stiffener at one end of the connecting rod formed at both ends of the load transferring material, Is formed to have a width (w ') which is a sum of the diameter (db) and the size corresponding to the amount of displacement (delta) outwardly, and a buckling performance is improved by using the circular steel pipe load transfer material Method.

Also, in the step (c), the connection hole is formed in a circular or track shape. The present invention provides a method of manufacturing an opening-form steel girder in which buckling performance is improved by using a circular steel pipe load transfer material.

Also, in the steps (f) and (g), the disassembly of the bolt and the second fastening are carried out in both end joints when the width w of the joint hole is dh + δ / 2. To provide a method of manufacturing an opening-form steel girder with improved buckling performance.

In the steps (f) and (g), the bolt disassembly and the second fastening are performed only when the width (w ') of the connecting hole in the corresponding connecting rod is dh + δ, The present invention provides a method of manufacturing an opening-form steel girder in which buckling performance is improved by using a circular steel pipe load transfer material.

Also, in step (e), the horizontal bracing is welded or bolted to the upper flange to provide a method of manufacturing an opening-form steel girder with improved buckling performance using a circular steel pipe load transfer material.

Further, in the step (e), when the horizontal bracing is bolted to the upper flange, a gusset plate is additionally provided between the two members so that the gusset plate is coupled to the upper flange. And to provide a method of manufacturing a steel girder.

In the step (h), a gusset plate is provided downward in the middle of the load transfer material, and a pair of the work pieces are connected to the lower end of the vertical stiffener and the gusset plate. To provide an improved method of manufacturing an opening-form steel girder.

Also, in step (h), it is desired to provide a method of manufacturing an opening-form steel girder in which buckling performance is improved by using a round steel pipe load transfer material characterized in that the workpiece is formed in the same cross-sectional configuration as the load transfer material.

(P _M ') is applied to the horizontal bracing through a process of fastening and disassembling the load transfer material to the upper member in accordance with the manufacturing step, in which the buckling performance is improved by using the circular steel pipe load transfer material of the present invention, It is possible to improve the compression resistance performance by complementing the low compression strength with respect to the tensile strength of the preformed horizontal bracing.

Also, by applying a circular steel pipe to the load transfer material, the torsional resistance performance is improved, thereby improving the safety against twisting and twisting of the opening-type steel girder during installation.

In addition, since a connecting block made of a plate material is provided at both ends of the circular steel pipe as a main component of the load transfer material, the vertical stiffener made of the plate material and the load transfer material can be easily connected to the plate plate.

Also, the load transfer material provided to correspond to the center-of-assembly spacing Ls, which is the center interval between the upper ends of the pair of the baffle plates, is increased by the distance displacement amount δ due to the outward directional conduction moment M of the upper member, When the bolts connecting the upper member to the load transfer material are disassembled, the load transfer material is reduced to the assembly length (Lts) while the design center distance (L) is maintained. However, since the connection hole provided in the load transfer material includes the width (w, w ') in consideration of the space displacement amount (?), The load transfer material is used as it is.

Further, the compression resistance of the horizontal bracing can be improved by merely adding a simple process of disassembling and re-fastening the bolts connecting the upper member and the load transfer material in the process of manufacturing the conventional opening-type steel girder, and the load- It is possible to reduce the cost of improving the performance of the conventional open-form steel girder.

In addition, it is very useful to improve the compression resistance of horizontal bracing and to improve the torsional resistance performance by applying a round steel pipe to the load transfer material used as an intermediate diaphragm in the end, It is effective.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention, Shall not be construed as limiting.
1 is a perspective view of a conventional open-form steel girder.
Figure 2a is a photograph of a horizontal bracing buckled in a conventional open-form steel girder.
Fig. 2B is a photograph showing a horizontal member of an intermediate die plate being twisted and a diagonal member being buckled in a conventional opening-type steel girder.
3A is a flow chart for calculating the tensile strength.
3B is a flow chart for calculating the compressive strength.
FIG. 3c is a graph showing the tensile strength (Prt) and the compressive strength (Prc) according to the unsupported lengths of the a-section steel and the CT section steel.
Fig. 4 is a view showing the torsional stiffness of the round steel pipe, the a-shaped steel and the CT steel.
Fig. 5A is a plan view of an opening-formed steel girder showing both before and after assembling the load-transferring material into the vertical stiffener in the opening-form steel girder of the present invention.
Figure 5b is a cross-sectional view along the line AA of the opening forming girder before assembling the load transfer material to the vertical stiffener in Figure 5a.
FIG. 5c is a cross-sectional view along the BB line showing the load flow of the opening forming steel girder in the first fastening step of assembling the load transfer material to the vertical stiffener by bolts in FIG. 5a. FIG.
6A is a plan view showing a load flow of an opening forming steel girder in a step of installing a horizontal bracing in an opening forming steel girder of the present invention.
Fig. 6B is a cross-sectional view along the CC line of the opening-form steel girder in Fig. 6A.
7A is a plan view showing a load flow of an opening forming steel girder in a disassembling step of separating a bolt provided between a load transfer material and a vertical stiffener in an opening forming steel girder according to the present invention.
Figure 7B is a cross-sectional view along the DD line showing the load flow acting on the horizontal bracing in Figure 7A.
8 is a flow chart for manufacturing a conventional open-form steel girder.
Fig. 9 is a flow chart for manufacturing an opening-form steel girder of the present invention.
FIG. 10A is a cross-sectional view showing the step (b) in FIG. 9, including a load transfer material.
FIG. 10B is a cross-sectional view showing the step (c) in FIG. 9, including a load transfer material.
FIG. 10C is a cross-sectional view showing the step (f) in FIG. 9, including the load transfer material.
FIG. 10D is a cross-sectional view including the horizontal bracing showing the step (f) in FIG.
FIG. 10E is a cross-sectional view showing the step (g) in FIG. 9, including a load transfer material.
11A is a perspective view showing one embodiment of the load transfer material of the present invention.
11B is a perspective view showing another embodiment of the load transfer material of the present invention.
11C is a perspective view showing still another embodiment of the load transfer material of the present invention.
FIG. 12A is a detailed view showing a first tightening of a load transfer material having a connecting hole in FIG. 10B. FIG.
FIG. 12B is a detailed view showing a second tightening of the load transfer material having the connecting hole in FIG. 10E. FIG.
FIG. 13A is a detailed view showing a first fastening of a load transfer material having a connecting hole in another embodiment in FIG. 10B. FIG.
FIG. 13B is a detail view showing a second order fastening of the load transfer material provided with the connecting hole of another embodiment in FIG. 10E. FIG.
14 is a cross-sectional view showing that, in the open-form steel girder of the present invention, a load transfer material is utilized as an intermediate diaphragm.
15A is a plan view showing that in the open-form steel girder of the present invention, the horizontal bracing is bolted to the upper flange.
15B is a cross-sectional detail view along the EE line showing that the horizontal bracing is bolted to the upper flange in Fig. 15A.

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

Hereinafter, the technical structure of the present invention will be described in detail with reference to the preferred embodiments.

Horizontal bracing and intermediate diaphragm applied to an opening-form steel girder are usually equipped with a ready-made a section steel or CT section steel in order to reduce the amount of steel material and to make it easy, to be.

 The horizontal bracing is arranged in a plane diagonal line in the opening forming steel girder, and the design center distance L is usually 3 to 4 m, so that the horizontal bracing length is 4.2 to 6.4 m. Such a horizontal bracing is susceptible to buckling because a section having a smaller cross-sectional dimension than a relatively long section is used. Generally, buckling is a phenomenon in which a large deformation occurs in the transverse direction even at a small load less than a proportional limit of the material when a member having a longer length is compared with the member sectional dimension, and the compressive strength of the member is remarkably reduced.

FIG. 3A is a flowchart for calculating the tensile strength, FIG. 3B is a flowchart for calculating the compressive strength, FIG. 3C is a graph for calculating the tensile strength Prt and the compressive strength Prc according to the unsupported lengths of the a- It is a picture.

3A to 3C, the tensile strengths of the a and C.T. sections having similar cross-sectional areas are constant regardless of the unsupported length. However, the compressive strength is 29.4% ~ 13.1% compared to the tensile strength in the case of the unsupported length of 4m ~ 6m, and 44.6 ~ 20.4% of the tensile strength in the case of the CT section steel. The compressive strength is less than half of the tensile strength can not do it. Therefore, the design load of the horizontal bracing is governed by the compressive force.

In order to improve the weak compressive strength against the tensile strength of such horizontal bracing, it is necessary to use a large cross-section or a short (non-supported) length. However, since the opening type steel girder has been developed for the purpose of reducing the construction cost of the conventional closed box steel girder, it is not suitable for the development purpose to arrange the large and dense members.

The method of manufacturing an opening-form steel girder according to the present invention makes it possible to introduce a tensile force into a horizontal bracing having a compressive strength that is weaker than that of a tensile strength by utilizing a load transfer material, thereby compensating for the compression force introduced into the horizontal bracing, Performance can be improved. That is, instead of slightly increasing the tensile strength with respect to the tensile strength, it is possible to improve the compression resistance performance, which is the design resistance performance of the horizontal bracing, by reducing the compressive force against the insufficient compressive strength.

Fig. 4 is a diagram showing the torsional stiffness of the round steel pipe, the a-shaped steel and the C.T.

4, the cross-sectional area of the round steel pipe is the same as that of the a steel pipe, while the torsional rigidity is 136 times smaller than that of the round steel pipe when the round steel pipe is 1, and 124 times smaller than that of the round steel pipe. This means that the torsional stiffness of circular steel pipe is 136 times and 124 times larger than that of other steel pipes, respectively.

The method of manufacturing an opening-form steel girder according to the present invention improves the torsional resistance performance by utilizing a circular steel pipe as a load transfer material and a later load transfer material as an intermediate diaphragm to improve the torsion and twist of the opening- The stability can be improved.

5A to 5C, 6A to 6B and 7A to 7B, a method of manufacturing an opening-form steel girder in which buckling performance is improved by using the circular steel pipe load transfer material of the present invention is described.

Fig. 5A is a plan view of an opening forming steel girder showing both before and after assembling a load transfer material to a vertical stiffener in an opening forming steel girder according to the present invention. Fig. 5B is a cross- FIG. 5C is a cross-sectional view taken along section line BB of FIG. 5A. FIG. 5C is a cross-sectional view taken along section line AA of FIG. 5A. In the first fastening step of assembling the load transfer material to the vertical stiffener by bolts, Fig.

Fig. 6A is a plan view showing the load flow of the opening forming steel girder in the opening-type steel girder of the present invention, and Fig. 6B is a cross-sectional view of the opening forming steel girder showing the section C-C in Fig. 6A.

FIG. 7A is a plan view showing a load flow of an opening forming steel girder in a disassembling step of separating a bolt provided between a load transfer material and a vertical stiffener in an opening forming steel girder of the present invention, FIG. 7B shows a cross section DD in FIG. , A horizontal cross-sectional view showing the load flow acting on the horizontal bracing.

A method of manufacturing an opening-form steel girder in which buckling performance is improved by using the circular steel pipe load transfer material of the present invention is characterized in that a pair of upper members 10 are manufactured (a) and a lower flange 20 The upper member 10 is installed on the upper part of the upper part (b).

The upper member 10 includes a pair of baffle plates 11 which are spaced apart from each other by a predetermined distance and which are continuous in the direction of the throttle axis and whose transverse upper surface is inclined outwardly, An upper flange 12 and a vertical stiffener 13 welded to the bumper plate 11 at intervals in the throttle direction at regular intervals.

Thus, the upper member 10 is first made, and then the lower flange 20 is provided so as to be continuous in the direction of the throttle, and the upper member 10 is mounted on the lower flange 20.

Thereafter, the load transfer material 30 is fastened to the vertical stiffener 13 so as to connect the vertical stiffener 13 and the vertical stiffener 13 in the horizontal direction (c).

As shown in FIGS. 5A to 5C, while maintaining the center distances of the upper ends of the pair of the baffle plates 11 at the assembly center distance Ls smaller than the design center distance L, The load transfer material 30 is primarily fastened to the upper side of the vertical stiffener 13 with the bolts 39 within the assembly center distance Ls.

Then, the lower end of the baffle plate 11 is welded to the lower flange 20 (d).

At this time, the lower end of the bumper plate 11 is pressed against the lower flange 20 in a state in which the load transfer member 30 assumes the tensile force P _M corresponding to the conduction moment M to be tilted out of the upper member 10. [ Respectively.

As described above, the conduction moment M that the upper member 10 tries to fall out through the steps (c) and (d) is determined by designing the center distances between the upper ends of the pair of the baffle plates 11 at the assembly center distance Ls And changes the length corresponding to the tensile force (P _M ) transfer and the interval displacement amount (?) To the load transfer material (30).

Thereafter, as shown in FIGS. 6A to 6B, a horizontal bracing 40 connecting the upper flange 12 with a diagonal line is installed (e).

The horizontal bracing 40 is welded or bolted to the upper flange 12 and no axial force is applied to the horizontal bracing 40 in this step.

7A to 7B, the bolts 39 connecting the vertical stiffener 13 and the load transfer material 30 are disassembled to release the tensile force P _M to the load transfer material 30, (40) is subjected to tensile force (P _M ') corresponding to the conduction moment (M) (f).

Since the tensile force P _M introduced through the horizontal bracing 40 serves to cancel the compressive force which is one of the requirements for buckling in the horizontal bracing 40, the relatively low compression of the horizontal bracing 40 Thereby improving the resistance performance.

Thereafter, as shown in Fig. 10E, the load transfer material 30 is secondarily fastened again to the vertical stiffener 13 with the bolts 39 (g).

14, a workpiece 50 connecting the central portion of the load transfer material 30 and the lower end of the vertical stiffener 13 is installed in the part or all of the load transfer material 30 (h) .

The work material 50 is provided on the entire surface of the load transfer material 30 or only in a place where the load transfer material 30 is twice as long as the gap between the load transfer material 30 and the vertical stiffener 13 And the intermediate diaphragm is completed to fabricate an opening-form steel girder by using an opening-form steel girder fabrication method in which the buckling performance is improved by using the circular steel pipe load transfer material of the present invention.

Fig. 8 is a flow chart for manufacturing a conventional opening-type steel girder, and Fig. 9 is a flowchart for manufacturing the opening-form steel girder of the present invention.

8 and 9, a conventional method of manufacturing an open-form steel girder according to the present invention will be described. In the case of a conventional open-form steel girder, a step (A) of manufacturing a pair of upper members as described above; (B) installing a pair of upper members on a continuous lower flange in a thrash direction; (C) installing an intermediate diaphragm while maintaining the center spacing of the upper ends of the pair of the baffle plates at the design center spacing (L); (D) welding the lower end of the baffle plate to the lower flange; Step E of installing a horizontal bracing joining the upper flange diagonally is performed to fabricate a conventional open-form steel girder.

In general, the opening type steel girder has torsional stiffness at the completion stage and is mostly applied to curved bridges than straight bridges. Since the longitudinal girders have longitudinal curvature on the longitudinal end, the cross sectional shape changes in three dimensions rather than a simple straight line. Therefore, considering the cross-sectional change in the ground position, the horizontal bracing connected to the upper flange by the oblique line is installed before the cross-sectional shape is fixed. Therefore, the horizontal bracing can be installed only after the cross-sectional shape is fixed through the step (D) in which the upper member is welded to the lower flange. In addition, since the horizontal bracing is interfered with the operation of the automatic welding equipment in welding the lower flange to the upper member and welding various reinforcements (not shown), installation of the horizontal bracing is allocated to the final operation.

Therefore, in the above-mentioned manufacturing procedure, the conventional opening-type steel girder has the intermediate diaphragm transferring the tensile force to the conduction moment M, and no axial force is applied to the horizontal bracing.

In order to cope with this, the method of manufacturing an opening-form steel girder according to the present invention is manufactured through the steps (a) to (h) as described above and FIG. Compared with the related art, the present invention is similar to the corresponding configuration in steps, but the conventional steps (f) to (h) have been further configured.

The opening forming steel girder according to the present invention can be manufactured by simply removing the bolts 39 connecting the upper member 10 and the load transferring member 30 in the process of manufacturing a conventional opening forming steel girder, And the load transfer material 30 can be utilized as an intermediate diaphragm in the future, so that the cost for improving the performance of the conventional open-form steel girder is substantially reduced.

This load transfer material 30 is used as a means for introducing a tensile force P _M 'to the horizontal bracing 40 and is later used as an intermediate diaphragm but is used as the same member without replacement or correction of the load transfer material 30. [ The center spacing on the upper end of the bumper plate 11 of the opening forming steel girder should correspond to the spacing distance delta extending from the centering distance Ls to the design center distance L due to the conduction moment M. [

In the opening-form steel girder according to the present invention, the load transfer material 30 is provided with a connecting hole 322 for accommodating the gap displacement amount? Without member replacement or correction, and the load transfer material 30 shown in Figs. 10A to 10E, 11A 11C, and 12A-12B.

FIG. 10A is a cross sectional view showing the step (b) in FIG. 9, including a load transfer material. FIG. 10B shows a step (c) FIG. 10C is a cross-sectional view showing the step of FIG. 9F, including a load transfer material. FIG. 10D shows a step of FIG. 9F, Fig. 10E is a cross-sectional view showing the step (g) in Fig. 9, including the load transfer material.

10A to 10E, the load transfer material 30 made of the assembly length Lts is formed in the connection hole 322 formed in the load transfer material 30 within the assembly center distance Ls, as shown in FIG. 10A. Is fitted into the bolt hole 131 formed in the vertical stiffener 13 so as to abut inward.

Thereafter, as shown in Fig. 10B, the load transfer material 30 is firstly fastened to the vertical stiffener 13 by the bolt 39. Fig. The conduction moment M that the upper member 10 tries to fall out due to the primary fastening causes the tensile force P _M and the spacing displacement amount delta in the load transfer material 30, Is increased at the design center distance (L).

The bolt 39 connecting the load transfer material 30 and the vertical stiffener 13 is disassembled as shown in Fig. 10C. Due to the disassembly of the bolt 39, the load transfer material 30 does not bear the tensile force P _M , so the interval displacement amount? Is eliminated and the length is reduced to the original assembly length Lts. On the other hand, the design center distance L remains unchanged due to the horizontal bracing 40 connecting the upper flange 12 and the horizontal bracing 40 provides a new load of tensile force P _M as shown in Fig. do.

When the load transfer material 30 in which the gap displacement amount delimited by the design center distance L has been increased by the distance displacement amount delta before the dismounting of the bolt 39 is provided in the load transfer material 30, The width w of the connecting hole is formed so that the hole 322 can contact the bolt hole 131 formed in the vertical stiffener 13 outwardly. Therefore, as shown in FIG. 10E, the load transfer material 30 The secondary fastening in which the vertical stiffener 13 is fastened again to the bolt 39 is performed.

Fig. 11A is a perspective view showing a load transfer material 30 in an opening-shape steel girder according to the present invention, Fig. 11B is a perspective view showing a load transfer material 30 in another embodiment in the opening- 11c are perspective views showing the load transfer material 30 of another embodiment in the opening-shape steel girder of the present invention.

11A to 11C, the load transfer material 30 may be formed into a shape having a circular cross-section at both ends of the circular steel pipe 31, So that the connecting block 32 can be coupled to the vertical stiffener 13.

11A, the vertical connecting plate 321 may include a plurality of vertical connecting plates 321. The vertical connecting plates 321 may be formed of a plurality of Hole 322 may be formed through the through-hole.

The connection hole 322 is formed in the vertical stiffener 13 in consideration of the distance displacement amount delta that the assembly center distance Ls is extended to the design center distance L due to the conduction moment M, (w, w ') having a size larger than a predetermined size dh.

Particularly, the connection hole 322 may be formed in a circular shape or a track shape having a long hole, and only the connection hole 322 of the connection block 32 on one side of the load transfer material 30 may be formed as a long hole And the connection hole 322 of the connection block 32 on both sides may be formed as a long hole.

The connection block 32 may further include an intermediate plate 33 for improving the weldability with the circular steel pipe 31 as shown in FIG. 11B.

That is, the connecting block 32 is provided with an intermediate plate 33 between the circular steel pipe 31 and the vertical connecting plate 321 to sandwich the intermediate plate 33 on the end of the circular steel pipe 31, (321), thereby improving the weldability.

11C, the connecting block 32 further includes a horizontal connecting plate 34 for connecting the vertical connecting plate 321 and the intermediate plate 33 to increase the rigidity of the vertical connecting plate 321 .

FIG. 12A is a detailed view showing the first fastening of the load transfer material having the connecting hole in FIG. 10B, and FIG. 12B is a detailed view showing the second fastening of the load transferring material having the connecting hole in FIG.

12A and 12B, the length of the load transfer material 30 in the first fastening shown in FIG. 12A and the length of the load transfer material 30 in the second fastening shown in FIG. The position of the bolt 39 and the bolt hole 131 is changed by the displacement amount delta generated by the conduction moment M. [

The bolt hole 131 is formed in the vertical stiffener 13 and the diameter dh of the bolt hole 131 may be formed to be larger than the diameter db of the bolt by a predetermined size, .

The connecting rod hole 322 of the present invention is formed in such a manner that the diameter dh of the bolt hole formed in the vertical stiffener 13 is smaller than the diameter dh of the bolt hole formed in the vertical stiffener 13 And is formed with a larger width w.

Here, the connecting hole 322 is formed in the connecting rod 32 formed at both ends of the load transfer material 30, the diameter dh of the bolt hole formed at the upper end of the vertical stiffener 13, (W = dh + [delta] / 2), which is a width (w) of the outer circumferential surface, plus a size corresponding to one half of the displacement amount (delta). In this case, the dismantling of the bolt 39 and the second fastening are both carried out at the both end linkage 32.

Fig. 13A is a detailed view showing the first fastening of the load transfer material having the connecting hole of another embodiment in Fig. 10B, and Fig. 13B is a detailed view showing the second fastening of the load transferring material having the connecting hole of the other embodiment in Fig. to be.

Here, the connection hole 322 is a diameter of the bolt hole formed at the upper end of the vertical stiffener 13 at one end of the connecting block 32 formed at both ends of the load transfer material 30, And a width w 'at the other end plus the diameter db of the bolt hole plus the size corresponding to the amount of displacement δ in the outward direction. In this case, the disassembly and the second fastening of the bolt 39 are performed only when the width w 'of the connecting hole in the corresponding connecting block 32 is dh + δ, and not in the connecting block 32 on the other end.

 14 is a cross-sectional view showing that, in the open-form steel girder of the present invention, a load transfer material is utilized as an intermediate diaphragm.

14, the gusset plate 70 is provided downward in the middle of the load transfer material 30 and a pair of workpieces 50 connecting the gusset plate 70 and the lower end of the vertical stiffener 13 So that it can be utilized as an intermediate diaphragm which plays the same role as the conventional open-form steel girder.

Here, the workpiece 50 may have various shapes, but it is preferable to apply a circular steel pipe having the same shape as that of the load transfer material 30.

Fig. 15A is a plan view showing that the horizontal bracing is bolted to the upper flange in the open-form steel girder of the present invention, Fig. 15B shows the cross-section EE in Fig. 15A and shows that the horizontal bracing is bolted to the upper flange It is a detailed cross section.

15A to 15B, the horizontal bracing 40 may be connected to the upper flange 12 by a bolt 39, and may further include a gusset plate 41 between the two members.

In the method of manufacturing an opening-form steel girder in which the buckling performance is improved by using the circular steel pipe load transfer material of the present invention as described above, the tensile force (P) is applied to the horizontal bracing through a process of fastening and disassembling the load- _M ') to improve the compressive resistance performance by complementing the low compressive strength compared to the tensile strength of the preformed horizontal bracing. By applying a circular steel pipe to the load transfer material, the torsional resistance performance is improved. The vertical stiffener made of a plate material and the load transfer material can be easily connected to the plate plate because the connecting rod made of a plate material is provided at both ends of the circular steel pipe which is the main component of the load transfer material. And is provided so as to correspond to the assembly center interval Ls, which is the center interval of the upper ends of the pair of the baffle plates The assembling center distance Ls is also widened to the design center distance L due to the outwardly directed conduction moment M of the rearmost upper side member and the bolts connecting the upper member and the load transferring material are disassembled The load transfer material is reduced to the assembly length (Lts) while the design center distance (L) is maintained. Therefore, the load transfer material should be re-manufactured, but the width of the connecting hole provided in the load transfer material w, w '), it is possible to simplify the manufacturing process by using the load transfer material as it is. In the conventional process for manufacturing an opening type steel girder, a simple process of disassembling and re-fastening the bolt connecting the upper member and the load transfer material , The compression resistance of horizontal bracing can be improved and the load transfer material can be used as an intermediate diaphragm to improve the performance of conventional open type steel girders. It is possible to improve the compression resistance of the horizontal bracing and to improve the torsional resistance by applying a round steel pipe to the load transfer material used as an intermediate diaphragm in the end, There is a very useful effect of improving safety against buckling.

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

10: upper member
11:
12: Upper flange
13: vertical stiffener
20: Lower flange
30: Load transfer material
31: Circular steel pipe
32: Links
39: Bolt
40: Horizontal bracing
41: gusset plate
50: Materials
70: gusset plate
L: Design-oriented Interpretation
Ls: Assembly center clearance
Lts: Assembly Length
delta: interval displacement amount
db: Diameter of the bolt
dh: diameter of the bolt hole
w, w ': Connection hole width

Claims (16)

(a) a pair of baffle plates 11 continuous in the direction of the throttle axis and inclined outward in the transverse plane, a pair of upper flanges 12 welded to the upper end of the baffle plate 11, A pair of upper members 10 made of a vertical stiffener 13 welded and installed at regular intervals in a direction;
(b) providing a lower flange (20) so as to be continuous in the throttling direction and installing a pair of upper members (10) on the lower flange (20);
(c) The vertical center stiffness of the vertical stiffener 13 and the vertical stiffener 13 in the assembled center interval Ls, while maintaining the center distances between the upper ends of the pair of the baffle plates 11 at the assembly center distance Ls, Firstly fastening the load transfer material (30) to the upper side of the vertical stiffener (13) with the bolt (39) so as to connect the stiffener (13) in the horizontal direction;
(d) Under the condition that the load transfer material 30 imposes the tensile force P _M corresponding to the conduction moment M to which the upper member 10 tries to fall out, the lower end of the bumper plate 11 is pressed against the lower flange 20, ;
(e) installing a horizontal bracing (40) so as to connect the upper flanges (12) on both sides between the load transfer material (30) and the load transfer material (30) in the diagonal direction of the same height;
(f) The bolts 39 connecting the vertical stiffener 13 and the load transfer material 30 are disassembled to release the tensile force P _M to the load transfer material 30, and the horizontal bracing 40 is provided with the conduction moment M (P _M ') corresponding to the tensile force (P _M ');
(g) secondarily fastening the load transfer material 30 to the upper side of the vertical stiffener 13 again with the bolts 39; And
(h) completing the intermediate diaphragm by installing a workpiece (50) connecting the central portion of the load transfer material (30) and the lower end of the vertical stiffener (13) in the partial or total load transfer material (30) ,
The load transfer material 30 is composed of a circular steel pipe 31 and a connecting rod 32 composed of a plate material coupled to both ends of the circular steel pipe 31. The connecting rod 32 is connected to a vertical connection Characterized in that it comprises a plate (321) and an intermediate plate (33) coupled between the circular steel pipe (31) and the vertical connecting plate (321) A method of making an open - form steel girder with improved buckling performance using a steel pipe - loaded transition material. The method according to claim 1,
In step (a)
The vertical stiffener 13 is formed with a bolt hole 131 at a position where the vertical stiffener 13 is coupled with the load transfer material 30 on the upper side,
Wherein the diameter dh of the bolt hole 131 is formed to be larger than the diameter db of the bolt 39. A method for manufacturing an opening-formed steel girder in which buckling performance is improved by using a circular steel pipe load transfer material. delete delete delete The method according to claim 1,
In the step (c)
The connecting plate 32 is horizontally formed to increase the rigidity of the vertical connecting plate 321 and a horizontal connecting plate 34 is formed to connect the vertical connecting plate 321 and the intermediate plate 33. [ A method of making an open - form steel girder with improved buckling performance using a steel pipe - loaded transition material. The method according to claim 1,
In the step (c)
The connection hole 322 is formed in the vertical stiffener 13 in consideration of the distance displacement amount delta that the assembly center distance Ls is extended to the design center distance L due to the conduction moment M, (w, w ') of a size larger than a width (dh) of the circular steel pipe, and the buckling performance is improved by using the round steel pipe load transfer material. The method according to claim 1,
In the step (c)
The connecting rod holes 322 are formed on the outer peripheral surface of the connecting rod 32 formed on both ends of the load transfer material 30 on the outer surface of the bolt hole 131 formed in the upper end of the vertical stiffener 13, Wherein the buckling performance is improved by using a circular steel pipe load transfer material having a width (w) which is a sum of a size corresponding to one half of the displacement amount (delta). The method according to claim 1,
In the step (c)
The connection hole 322 corresponds to the diameter db of the bolt hole 131 formed on the upper end of the vertical stiffener 13 at one end of the connecting block 32 formed on both ends of the load transfer material 30, Of the bolt hole (131) and a width (w ') of the bolt hole (131) at the other end plus the size corresponding to the amount of displacement (?) Outwardly. A method of making an open - form steel girder with improved buckling performance. The method according to claim 1,
In the step (c)
Wherein the connecting hole (322) is formed in a circular shape or a track shape, and the buckling performance is improved by using the round steel pipe load transfer material. The method according to claim 1,
In steps (f) and (g)
The disassembly of the bolt 39 and the second fastening are both performed in the both end connecting rods 32 when the width w of the connecting rod hole 322 is dh + δ / 2. A method of making an open - form steel girder with improved buckling performance. The method according to claim 1,
In steps (f) and (g)
The disassembly and the second fastening of the bolt 39 are performed only when the width w 'of the connecting hole 322 in the corresponding connecting block 32 is dh + δ and not in the connecting block 32 of the other end A method of making an open - form steel girder with improved buckling performance using a circular steel pipe load transfer material. The method according to claim 1,
In the step (e)
Wherein the horizontal bracing (40) is welded or bolted to the upper flange (12), wherein the buckling performance is improved using a round steel pipe load transfer material. 14. The method of claim 13,
In the step (e)
And a gusset plate (41) is additionally provided between the two members when the horizontal bracing (40) is bolted to the upper flange (12). The buckling performance is improved by using a circular steel pipe load transfer material Method of making steel girders. The method according to claim 1,
In step (h)
The gusset plate 70 is provided downward in the middle of the load transfer material 30 so that the pair of workpieces 50 are connected to the lower end of the vertical stiffener 13 and the gusset plate 70. [ A method of making an open - form steel girder with improved buckling performance using ash. The method according to claim 1,
In step (h)
Wherein the work material (50) is formed to have the same cross section and structure as the load transfer material (30), wherein the buckling performance is improved by using the round steel pipe load transfer material.

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