KR20060019307A - Reinforcement device of steel composite bridge and construction method - Google Patents

Abstract

The present invention relates to a steel composite bridge reinforcement device and a construction method thereof, and more particularly, by installing a steel box girder and installing a slab on the upper portion of the steel composite bridge reinforced step by installing a reinforcement device in multiple stages By applying prestress, the flexural rigidity corresponding to the size of the bending moment applied to the steel composite bridge can be secured, the cross section of the steel box girder can be minimized, and the long span of the steel composite bridge can be minimized, and the amount of steel in the steel box girder is minimized. The present invention relates to a steel composite bridge reinforcement device and a construction method thereof that can reduce the dead load and minimize the plant joint.

The reinforcement device of the steel composite bridge according to the present invention is a steel box girder having a flange of the upper and lower portions and the abdominal plate of the left and right sides, respectively, and a tension portion tensioned by the bending moment in the steel composite bridge composed of a slab constructed on top of the steel box girder. A reinforcement device for a steel composite bridge for reinforcing the bending stiffness of the tensile portion by applying prestressing, the tension of the upper and lower flanges of the steel box girder so as to face each other in the longitudinal direction of the steel composite bridge in the tensile portion of the steel composite bridge A first support member fixed to the flange, a first tension member having both ends extending to the first support member as an elongated member, and supported by each of the first support members to exert a tensile force on the first tension member. A longitudinal direction of the steel composite bridge between the first tensioning means connected to each of both ends of the first tension member and the first support member A second support member fixed to a flange of a steel box girder to which the first support member is fixed so as to face each other at both sides of the furnace, and a second tension member having both ends extending to the second support member as an elongated member; And second tensioning means supported on each of the second support members and connected to both ends of the second tension member to apply a tensile force to the second tension member.

In addition, the construction method of the reinforcement device of the steel composite bridge according to the present invention, the step of installing a steel box girder on the top of the alternating and piers, and by the weight of the slab to be constructed on the top of the steel box girder on the first tension member Applying a tensile force to apply a prestress corresponding to the added bending moment; constructing a slab on top of the steel box girder; and corresponding to a bending moment added due to the live load of the steel composite bridge to the second tension member. And applying a tensile force for applying prestress.

Steel composite bridge, prestress

Description

Reinforcement device of steel composite bridge and construction method {A DEVICE FOR STRENTHENING STEEL BOX GIRDER BRIDGE AND CONSTRUCTION METHOD THEREOF}

1 is a plan view showing a single steel composite bridge to which the reinforcement device of the steel composite bridge according to an embodiment of the present invention is applied

Figure 2 is a side view showing a single steel composite bridge to which the reinforcement device of the steel composite bridge according to an embodiment of the present invention is applied

Figure 3 is a side view showing a continuous steel composite bridge to which the reinforcement device of the steel composite bridge according to an embodiment of the present invention

Figure 4 is a perspective view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention

5 is a perspective view showing the reinforcement device of the steel composite bridge according to an embodiment of the present invention

6 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention.

7 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention.

8 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to another embodiment of the present invention.

9a to 9c is a relationship between the bending stiffness applied to a single steel composite bridge and the bending moment of a single steel composite bridge by the reinforcing device of a steel composite bridge according to an embodiment of the present invention and the reinforcement device of a steel composite bridge according to an embodiment of the present invention Side view of single steel composite bridge conceptually showing construction method

<Short description of the major reference symbols>

1 steel composite

     2 steel box girder

         2a, 2b flange

         2c, 2d abdominal plate

         3 diaphragm

     4 slab

10 First supporting member

20 first tension member

30 First Tensile Member

40 second supporting member

50 Second tension member

60 Second Tension Member

The present invention relates to a steel composite bridge reinforcement device and a construction method thereof, and more particularly, by installing a steel box girder and installing a slab on the upper portion of the steel composite bridge reinforced step by installing a reinforcement device in multiple stages By applying prestress, the flexural rigidity corresponding to the size of the bending moment applied to the steel composite bridge can be secured, the cross section of the steel box girder can be minimized, and the long span of the steel composite bridge can be minimized, and the amount of steel in the steel box girder is minimized. The present invention relates to a steel composite bridge reinforcement device and a construction method thereof that can reduce the dead load and minimize the plant joint.

The steel composite bridge is manufactured by connecting a steel box girder made by connecting a steel box having upper and lower flanges and an abdominal plate of left and right sides between an alternating (pier) and a pier and constructing a slab on an upper portion of the steel box girder. The steel composite bridge receives a bending load under the live load of the steel composite bridge itself and the progress of the vehicle, and sags downward (see FIGS. 9A to 9C). Due to the bending moment as described above, a portion to be tensioned in the steel composite bridge is generated. For example, in a single steel composite bridge where both ends are supported alternately, the lower flange of the steel box girder is tensioned between the shifts (see Fig. 2), and in a continuous steel composite bridge where a certain position between both ends is supported by the bridge. The lower flange of the steel box girder is tensioned between the and pier and the upper flange and slab of the steel box girder are tensioned about the position supported by the pier (see FIG. 3).

The steel composite bridge is preferably designed to be sufficiently larger than the maximum value of the bending moment so that the bending strength can withstand the bending moment. In general, the flexural strength of steel composite bridges has the same value for the entire span if the structure is the same for the entire span. The bending moment is maximized at the intermediate point where the bending moment is applied under the assumption that the structure of the steel composite bridge is the same for the entire span and the uniform load is applied to the entire span, and the value is the distance between the shifts and the piers. The larger the span becomes, the larger it becomes. Therefore, in order to lengthen the steel composite bridge, the flexural strength at the position where the maximum bending moment is applied must have a size that can resist the maximum bending moment.

To this end, conventionally, a method of increasing the rigidity of the steel box girder itself or applying a prestress to the tensile portion of the steel composite bridge which is tensioned under bending moment is used. However, in order to increase the rigidity of the steel box girder itself, it is necessary to increase the cross-sectional size of the steel box girder or increase the thickness of the upper and lower flanges and the left and right abdominal plates forming the steel box girder, which increases the amount of steel in the steel box girder. This increases the cost of construction.

In particular, the conventional steel box girder is manufactured using a locally thick iron plate only the part that takes the maximum bending moment. In this case, both sides of the thick iron plate and the thin iron plate connected thereto are connected to each other by butt welding, and accordingly, a welding point in a factory is increased in manufacturing a conventional steel box girder. Therefore, in the manufacture of the conventional steel box girder, the use of thick steel plate and the increase of welding points, the steel bridge manufacturing cost, the non-destructive inspection cost of the welded portion, etc. is increased.

On the other hand, the steel box girder is produced by connecting several steel boxes at the site where the steel composite bridge is to be installed, in general, the size of the steel box is manufactured and transported so that its weight is below a certain level. However, the conventional steel box girder increases the cross-sectional size so that sufficient bending rigidity is secured and is made of thick steel sheet, so the length is shorter than the weight, so that the number of steel boxes is increased for the same area, and thus the site fastening point using high-strength bolts Not only increases the lengthening of the bridge, but also increases the material and installation costs.

In addition, as described above, the conventional steel box girder has a large cross-sectional size, thereby securing the space of the die and securing the clearance of the river crossing bridge.

Therefore, in recent years, the prestressing method has been increasingly adopted. 'Assembly type tensile steel sheet' disclosed in Korean Utility Model No. 20-0193344, 'Integral girder applying deflection and prestress' disclosed in Korean Utility Model No. 20-0305665, and Korean Patent No. 10-0427405 The PS composite girder or the like discloses a bridge reinforcement device for applying prestress by tension to a lower portion of a bridge, which is a portion to which a bending moment is applied and is tensioned.

However, as described above, the bending moment is generally increased in size at the portion where the steel composite bridge is tensioned toward the middle point of the tensile portion. On the contrary, the flexural strength is the same for the entire span if the structure of the steel box girder is the same (see Fig. 9a). As described above, the steel composite bridge should be designed so that the bending stiffness is larger than the maximum value of the bending moment. By the way, in the conventional bridge, the prestress is applied by the reinforcement device to the reinforced portion, the bending strength is increased to the same size throughout the portion where the reinforcement device is installed. Therefore, the conventional reinforcement device of the bridge is to be reinforced so as to have a bending strength of unnecessary size up to a portion where the magnitude of the bending moment is relatively small. This has the disadvantage of consuming unnecessary materials as unnecessary reinforcement.

Meanwhile. The tension force reinforced by the reinforcement device of the bridge is preferably distributed and transmitted throughout the cross section of the bridge. However, the conventional reinforcement device has a disadvantage that the portion connected to the bridge is seen in cross section and is locally concentrated at the portion to which the bridge is connected and transmitted to the bridge.

The present invention is to solve the above problems, an object of the present invention is to reduce the amount of steel used in the production of steel box girders of steel composite girder by reinforcing the tensile portion by applying prestress to the tensile portion of the steel composite bridge It is to provide a reinforcement device and a construction method of a steel composite bridge that can minimize the cross-sectional size of the bridge and make the bridge longer.

In particular, an object of the present invention is to produce a steel box girder with a minimum thickness of steel plate that can resist the bending moment due to the self-weight of the steel box girder and to prestress corresponding to the bending moment added by the slab self-weight and active The present invention provides a reinforcing device for a steel composite bridge and its construction method which can minimize the joint in a factory by applying the tensile portion of the steel composite bridge.

In addition, the object of the present invention is to reduce the cross-sectional size and weight of the steel box girder to reduce the number of steel boxes connected in the field to reduce the site connection point, as well as to reduce the material cost and installation cost, as well as to minimize the cross-sectional size And a reinforcing device for a steel composite bridge and a construction method thereof so as to sufficiently secure a clearance of a river crossing bridge.

Particularly, an object of the present invention is to provide a reinforcement device for a steel composite bridge and a construction method thereof, which can secure sufficient bending strength by gradually adding prestress to a portion where the magnitude of the bending moment is relatively large according to the change of the bending moment size. It is.

Another object of the present invention is to provide a reinforcement device for a steel composite bridge in which the tension applied by the reinforcement device is distributed in the cross section of the steel box girder by transferring the reinforcing device to the diaphragm of the steel box girder.

The reinforcement device of the steel composite bridge according to the present invention for achieving the above object, the steel box girders each having a top and bottom flange and the left and right sides of the abdomen plate and the steel composite bridge consisting of a slab constructed on top of the steel box girder A reinforcement device for a steel composite bridge for applying prestress to a tensile section tensioned by a moment to reinforce the flexural rigidity of the tensile section, wherein the reinforcement device is positioned so as to face each other in the longitudinal direction of the steel composite bridge in the tensile section of the steel composite bridge. A first support member fixed to the tensioned flange of the upper and lower flanges of the steel box girder, a first tension member having both ends extending to the first support member as an elongated member, and supported by each of the first support members First tension means connected to each of both ends of the first tension member to apply a tensile force to the first tension member, and the first support portion A second support member fixed to a flange of a steel box girder on which the first support member is fixed so as to face each other in the longitudinal direction of the steel composite bridge between the ashes, and both ends of the second support as elongated members; And a second tensioning member extending to the member and second tensioning means supported on each of the second support members and connected to each of both ends of the second tension member to apply a tensile force to the second tension member. .

In addition, the reinforcement device of the steel composite bridge according to the present invention, the first support member or the second support member is a bracket having a through hole formed through the through hole, both ends of the first tension member or the second tension member, respectively; Fixed to the flange of the steel box girder, wherein the first tension member or the second tension member is a steel rod having a coupling portion at both ends thereof, and the first tension means or the second tension means are the first support member or the first tension member, respectively. A member coupled to a coupling portion formed at both ends of each of the first or second tension member at both ends of each of the first and second tension members exposed through the through-holes of each of the supporting members. As the first support member or the second support member is supported in close contact with each bracket to apply a tensile force to the first tension member or the second tension member .

In addition, the reinforcement device of the steel composite bridge according to the present invention, the first support member or the second support member is a bracket with a tapered shape of the fixing hole is formed as the diameter decreases as it proceeds in a direction facing each other through the fixing holes, respectively The first tension member or the second tension member is fixed to the flange of the steel box girder so that both ends of the first tension member or the second tension member pass, the first tension member or the second tension member is a steel wire, An outer circumferential surface is tapered corresponding to the taper of the fixing hole, and both ends of each of the first or second tension member exposed through the fixing hole of each of the first and second supporting members A wedge-shaped anchoring device having a tightening hole for inserting the rod, wherein the first tension member or the second tension member is inserted into the tightening hole to provide a tensile force. In the applied state, the first tension member or the second tension member is fixed to the first tension member or the second tension member by being gradually entered into the fixing hole, tightened by the fixing hole, and supported by the fixing hole. It is characterized by applying a tensile force to the member.

In addition, the reinforcement device of the steel composite bridge according to the present invention, the first tension member is applied a tensile force for applying a pre-stress corresponding to the bending moment added by the weight of the slab constructed on top of the steel box girder, (2) The tension member is characterized in that a tensile force is applied to apply a prestress corresponding to the added bending moment due to the live load of the steel composite bridge.

In addition, the reinforcement device of the steel composite bridge according to the present invention, the inside of the steel box girder is provided with a diaphragm connected to the upper and lower flanges and the abdominal plate of the left and right sides, the first support member or the second support member is the diaphragm At the point where the diaphragm and the tensioned flange of the steel box girder at the provided position is characterized in that connected to the fixed flange of the diaphragm and the steel box girder at the same time.

In addition, the reinforcement device of the steel composite bridge according to the present invention, the through-hole is provided with a line through which the first tension member or the second tension member passes so that the first tension member or the second tension member through the through hole. In the steel box girder characterized in that it further comprises a guide member fixed to the flange to be tensioned.

In addition, the reinforcement device of the steel composite bridge according to the present invention, the second support member is characterized in that the through hole for passing the first tension member is formed.

In addition, the construction method of the reinforcement device of the steel composite bridge according to the present invention, the steel box girders are installed in the upper portion of the alternating and piers, and the first tension member by the weight of the slab to be constructed on the upper portion of the steel box girder Applying a tensile force to apply a prestress corresponding to the added bending moment, constructing a slab on top of the steel box girder, and adding a bending moment due to the live load against the dead load of the steel composite bridge to the second tension member. And applying a tensile force to apply a corresponding prestress.

Hereinafter, with reference to the embodiment shown in the drawings will be described in more detail the reinforcing device of the steel composite bridge according to the present invention.

1 is a plan view showing a single steel composite bridge reinforced steel composite bridge according to an embodiment of the present invention, Figure 2 is a single steel composite bridge reinforced steel composite bridge according to an embodiment of the present invention Figure 3 is a side view, Figure 3 is a side view showing a continuous steel composite bridge reinforced steel composite bridge according to an embodiment of the present invention, Figure 4 is a steel composite bridge reinforced device according to an embodiment of the present invention 5 is a perspective view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention, Figure 6 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention, 7 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to an embodiment of the present invention.

Referring to the drawings, a single steel composite bridge (1) to which the reinforcement device of the steel composite bridge according to the present invention is applied connects a plurality of steel boxes having upper and lower flanges (2a, 2b) and the left and right side abdominal plates (2c, 2d) The steel box girder 2 is installed, and the slab 4 is poured on the steel box girder 2 and manufactured. Steel box girder 2 formed as described above is provided with longitudinal ribs (4, 5) and transverse ribs (not shown) for reinforcement, the diaphragm (3) at a predetermined interval inside the steel box girder (2) Is installed. The diaphragm 3 is to prevent buckling of the steel box girder 2 and is connected to the upper and lower flanges 2a and 2b and the abdominal plates 2c and 2d in the steel box girder.

The reinforcement device of the steel composite bridge according to the present invention is to reinforce the tensile portion of the steel composite bridge by applying a prestress to the tension portion is applied to the bending moment to the steel composite bridge (1). Referring to the drawings, the tensioned portion, which is tensioned by the bending moment, is located in the lower flange 2b of the steel box girder 2 between alternations in the case of a single steel composite bridge as in FIG. 2, and in continuous steel as in FIG. In the case of a composite bridge, it is located in the upper flange 2a of the steel box girder 2 and the lower flange 2b of the steel box girder 2 between the alternating and the piers about the portion supported by the pier. The reinforcement device of the steel composite bridge according to the present invention is preferably installed symmetrically based on the point where the bending moment is maximized in the steel composite bridge (1).

Referring to the drawings, the reinforcement device of the steel composite bridge according to the present invention is for reinforcing the tension portion of the steel composite bridge (1) in multiple stages, the first support member 10, the first tension member 20, the first Tension means 30, a second support member 40, a second tension member 50, and a second tension means 60.

The first support member 10 is for supporting the first tensioning means 30, and the upper flange 2a or the lower flange 2b of the steel box girder 2, which is a tension part of the steel composite bridge 1, It is fixed to). The first support member 10 is fixed to the upper or lower flanges 2a and 2b of the steel box girder 2 so as to face each other at both sides in the longitudinal direction at the tension portion of the steel composite bridge 1. . Referring to the drawings, the first supporting member 10 is a bracket having a through hole 11 formed therein. The bracket, which is the first support member 10 as described above, has upper or lower flanges 2a and 2b of the steel box girder 2 such that both ends of the first tension member 20 pass through the through hole 11. Attached and fixed to the inner surface of the). In particular, the first support member 10 transmits the tensile force applied to the first tension member 20 to the steel box girder (2). Therefore, the first support member 10 is preferably connected to the steel box girder 2 so as to transfer the tensile force applied to the first tension member 20 to the steel box girder 2 well. To this end, in the reinforcement device of the steel composite bridge according to the present invention, the first support member 10 is not only the upper or lower flanges 2a and 2b of the steel box girder 2 but also the left and right abdominal plates of the steel box girder 2 ( It is fixed to the diaphragm 3 connected to 2c and 2d simultaneously.

The first tensioning member 20 is an elongated member that is tensioned by the first tensioning means 30 to apply a tension force to the tensioned portion of the steel composite bridge 1 by the tension force. The first tension member 20 is generally made of steel wire or steel rods and an embodiment in which the tension member 20 is a steel rod is shown in FIGS. 1 to 7. Both ends of the first tension member 20 extend to the first support member 10 and are connected to the first tension means 30.

The first tension means 30 is supported by each of the first support members 10 and is connected to each of both ends of the first tension member 20 to exert a tensile force on the first tension member 20. Referring to the drawings, the first tension means 30 is distal to coupling portions formed at both ends of the first tension member 20 exposed through the through holes 11 of the first support members 10. As a member coupled to the coupling portion of the first tension member 20 from one side, one surface of the first tension member 20 is tightly supported by the bracket that is the first support member 10 to apply a tensile force to the first tension member 20. The drawing shows an embodiment in which the coupling portion of the first tension member 20 is formed by forming a male screw and the first tension means 30 coupled to the coupling portion is a nut screwed into the coupling portion.

The second support member 40 is for supporting the second tensioning means 60 so as to face each other in the longitudinal direction of the steel composite bridge 1 between the first support members 10. It is fixed to the upper or lower flanges (2a, 2b) of the steel box girder (2). Referring to the drawings, the second support member 40 is a bracket having a through hole 41 formed therein. The bracket, which is the second support member 40 as described above, has upper or lower flanges 2a and 2b of the steel box girder 2 such that both ends of the second tension member 50 pass through the through hole 41. Attached and fixed to the bottom or top of the). In particular, the second support member 40 transmits the tensile force applied to the second tension member 50 to the steel box girder (2). Therefore, the second support member 40 is preferably connected to the steel box girder 2 so as to transfer the tensile force applied to the second tension member 50 to the steel box girder 2 well. To this end, in the reinforcement device of the steel composite bridge according to the present invention, the second support member 40 has the upper or lower flanges 2a and 2b of the steel box girder 2 as well as the left and right side abdominal plates of the steel box girder 2 ( It is fixed to the diaphragm 3 connected to 2c and 2d simultaneously. On the other hand, the second support member 40 is formed with a through-hole 43 through which the first tension member 20 passes and guided while the first tension member 20 passes.

The second tension member 50 is an elongated member that is tensioned by the second tensioning means 60 and is pulled by the second tensioning means 60 so that the tensioned portion of the steel composite bridge 1 between the first support members 10. It is to add additional tension to the. The second tension member 50 is generally made of a steel wire or a steel bar and an embodiment of a steel bar is shown in FIGS. 1 to 7. Both ends of the second tension member 50 extend to the second support member 40 and are connected to the second tension means 60.

The second tension means 60 is supported by each of the second support members 40 and is connected to each of both ends of the second tension member 50 to exert a tensile force on the second tension member 50. Referring to the drawings, the second tension means 60 may be formed at both ends of both ends of the second tension member 50 exposed through the through holes 41 of each of the second support members 40. As a member coupled to the coupling portion formed at both ends of the tension member 50, one surface of the tension member 50 is tightly supported by the bracket which is the second support member 40 to apply a tensile force to the first tension member 50. The drawing shows an embodiment in which the coupling portion of the second tension member 50 is formed by forming a male screw and the second tension means 60 coupled to the coupling portion is a nut screwed into the coupling portion.

On the other hand, the reinforcement device of the steel composite bridge according to the present invention is provided with a through hole so that the first tension member 20 or the second tension member 50 passes through the through hole. Or a guide member (not shown) fixed to the upper or lower flanges 2a and 2b of the steel box girder 2 on the line through which the second tension member 50 passes. The guide member guides the first tension member 20 and the second tension member 50 not to be separated. The guide member has a second support member 40 that guides the first tension member 20 by forming a through hole 43 through which the first tension member 20 passes from the second support member 40. The through hole 43 and its structure are substantially the same.

8 is a cross-sectional view showing a reinforcing device of a steel composite bridge according to another embodiment of the present invention. Unlike the embodiment illustrated in FIGS. 1 to 7, the reinforcement device of the steel composite bridge according to another embodiment of the present invention illustrated in FIG. 8 includes a wire as the first tension member 20 and the second tension member 50. It is characterized in that the first tension member 30 and the second tension member 60 for applying a tensile force to it is a fixing device which is tightened by the first support member 10 and the second support member 40. Meanwhile, in FIG. 8, since the first support member and the second support member, the first tension member and the second tension member, and the first tension member and the second tension member have similar structures, they are represented by the same configuration. This is for convenience of description. Referring to the drawings, the first support member 10 and the second support member 40 are brackets formed with tapered fixing holes 15 and 45 whose diameter decreases as they proceed in a direction facing each other. It is fixed to the flanges (2a, 2b) of the steel box girder (2) so that both ends of the first tension member 20 and the second tension member 50 pass through the (15, 45), respectively. The first tension member 20 and the second tension member 50 are steel wires. The first tension means 30 and the second tension means 60 have outer circumferential surfaces 35 and 65 having a taper corresponding to the taper of the fixing holes 15 and 45, and the first support member ( 20) and fastening for inserting both ends of each of the first and second tension members 20 and 50 exposed through the fixing holes 15 and 45 of the second support member 50, respectively. It is a wedge in which the holes 36 and 66 are formed. In the first tension means 30 and the second tension means 60, the first tension member 20 and the second tension member 50 are inserted into the tightening holes 36 and 66, and a tensile force is applied thereto. Gradually enters the fixing holes 15 and 45, is tightened by the fixing holes 15 and 45, and supported by the fixing holes 15 and 45, thereby providing the first and second tension members 20 and 50. ) Is fixed to the tightening holes (36,66) to apply a tensile force to the first tension member (20) or the second tension member (50).

On the other hand, 9a to 9c is the relationship between the bending stiffness applied to a single steel composite bridge and the bending moment of a single steel composite bridge by the reinforcement device of the steel composite bridge according to an embodiment of the present invention and the reinforcement of the steel composite bridge according to an embodiment of the present invention This is a side view of a single steel composite bridge conceptually showing the construction method of the device.

Referring to the drawings, the construction method of the reinforcement device of the steel composite bridge according to the present invention comprises the steps of installing the steel box girder (2) in the upper portion of the alternating and piers, and the steel box girder (2) on the first tension member (20) Applying a tensile force to apply a prestress corresponding to the bending moment (M2-M1) added by the weight of the slab (4) to be constructed on the top of the slab; and the slab (4) on the top of the steel box girder (2) And a tensile force for applying a prestress corresponding to the bending moment added by the live load to the bending moment due to the dead load of the steel composite bridge 1 to the second tension member 50.

9A illustrates a state in which steel box girders 2 are alternately installed. The bending strength S1 of the steel box girder 2 itself in the tension portion L of the steel box girder 2 may be large enough to resist the bending moment M1 due to the weight of the steel box girder 2 itself. Have In this case, the bending strength S1 of the steel box girder 2 itself is designed to have a minimum size that can resist the bending moment M1, thereby minimizing the size of the steel box girder 2 and its own weight.

FIG. 9B shows a state in which a tension force is applied to the first tension member 20 to form a prestress corresponding to a bending moment added by the weight of the slab 4 to be constructed thereon on the steel box girder 2. It is. By the construction of the slab 4, the bending moment M2 is generated in the steel composite bridge 1 by the composite dead weight of the steel box girder 2 and the slab 4. That is, the bending moment of M2-M1 size is added to the bending moment M1 by the load of the steel box girder 2 itself to the steel composite bridge 1 by the construction of the slab 4. Accordingly, the steel box girder 2 and the slab 4 are formed by applying a tensile force to the first tension member 20 to form a prestress corresponding to the bending moment of M2-M1 size added by the construction of the slab 4. It is possible to add a bending strength (S2) of a size that can withstand the bending moment (M2) due to the composite dead weight (). The magnitude of the tensile force applied to the first tension member 20 is preferably equal to or larger than the size capable of forming a prestress of a size that cancels the bending moment of the size of M2-M1 to be added to the construction of the slab 4. Do.

As described above, after applying the tensile force to the first tension member 20, the slab (4) is constructed on the upper portion of the steel box girder (2).

 9c shows that the slab 4 is constructed on the upper portion of the steel box girder 2 as described above, and the live load is applied in consideration of the live load applied to the progress of the vehicle to the dead load by the steel box girder 2 and the slab 4. Figure 2 shows a state in which a tensile force is applied to the second tension member 50 to form a prestress corresponding to the bending moment added thereto. The construction of the slab (4) is applied to the composite composite load by the steel box girder (2) and the slab (4) to the steel composite bridge (1) and to the dead load by the progress of the car, etc. to the steel composite bridge (1) An additional live load is applied, resulting in the bending moment M3. That is, the bending moment of size M3-M2 is added to the bending moment M2 by the dead load of the steel composite bridge 1 to the steel composite bridge 1. Therefore, by applying a tensile force to the second tension member 50 to form a prestress corresponding to the bending moment of the M3-M2 size to be added by the live load, the size that can resist the dead load and the bending moment (M3) due to the live load It is possible to add the bending strength (S3) of. The magnitude of the tensile force applied to the second tension member 50 is preferably equal to or larger than the size capable of forming a prestress of a size that cancels the bending moment of the M3-M2 size to be added by the live load.

Referring to the drawings, the reinforcement device of the steel composite bridge according to the present invention by forming a pre-stress step by step in the tensile portion of the steel composite bridge (1) to avoid unnecessary reinforcement according to the size of the bending moment and to reinforce only the portion that needs to be reinforced The bending rigidity required for safety can be secured and the waste of material can be prevented. In addition, since a reinforcement device may be installed in a portion that needs sufficient reinforcement, a thick steel plate may be used in a portion that requires reinforcement when manufacturing a steel box girder, thereby reducing the process of butt welding and reducing the amount of steel.

Reinforcement device and construction method of the steel composite bridge according to the present invention having the configuration as described above to reduce the amount of steel used in the production of steel box girder of the steel composite bridge by applying a prestress to the tensioned portion of the steel composite bridge In addition to minimizing the cross-sectional size of the steel box girder, it is possible to make the bridge longer.

In particular, the steel composite bridge reinforcement device and its construction method is a steel plate of the smallest thickness that can resist the bending moment due to the self-weight of the steel box girder to produce a steel box girder over the cells and by the slab self-weight and active Stepwise application of the prestress corresponding to the added bending moment to the tensile part of the steel composite bridge has the advantage of minimizing seam in the plant.

In addition, the reinforcement device and construction method of the steel composite bridge according to the present invention can reduce the material connection and installation cost by reducing the number of steel boxes connected in the field by reducing the cross-sectional size and weight of the steel box girder In addition, by minimizing the cross-sectional size has the advantage that can secure enough margin of the geometry space and cross-section bridge.

In particular, the reinforcement device and construction method of the steel composite bridge according to the present invention has the advantage that the sufficient bending strength can be secured by adding the pre-stress to the relatively large portion of the bending moment according to the change of the bending moment size. .

In addition, the reinforcement device and construction method of the steel composite bridge according to the present invention has the advantage that the tension applied by the reinforcement device is distributed in the cross section of the steel box girder by transmitting the reinforcement device to the diaphragm of the steel box girder in cross section. .

The reinforcing device and construction method of the steel composite bridge described above and shown in the drawings are only one embodiment for carrying out the present invention, and should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is defined only by the matters set forth in the claims below, and the embodiments which have been improved and changed without departing from the gist of the present invention will be apparent to those skilled in the art. It will be said to belong to the protection scope of the present invention.

Claims (8)

Reinforce the flexural stiffness of the tensioned section by applying prestress to the tensioned section by the bending moment in a steel composite girder consisting of a steel box girder having upper and lower flanges and an abdominal plate on the left and right sides, and a slab constructed on top of the steel box girder. In the reinforcement device of steel composite bridge for A first support member fixed to a flange which is tensioned among upper and lower flanges of the steel box girder so as to face each other in the longitudinal direction of the steel composite bridge in the tension portion of the steel composite bridge; A first tension member having an elongate member extending at both ends to the first support member; First tensioning means supported by each of the first support members and connected to both ends of the first tension member to apply a tensile force to the first tension member; A second support member fixed to a flange of the steel box girder to which the first support member is fixed so as to face each other in the longitudinal direction of the steel composite bridge between the first support members; A second tension member having both ends extending to the second support member as an elongated member; And a second tension means connected to each of both ends of the second tension member so as to be supported by each of the second support members to exert a tensile force on the second tension member. The method of claim 1, The first supporting member or the second supporting member is a bracket having a through hole, and is fixed to a flange of the steel box girder so that both ends of the first or second tension member pass through the through hole, respectively. The first tension member or the second tension member is a steel bar having a coupling portion at both ends, The first tensioning means or the second tensioning means may be formed at ends of both ends of each of the first tension member or the second tension member exposed through the through-holes of the first support member or the second support member, respectively. A member coupled to a coupling portion formed at both ends of each of the first tension member or the second tension member, the first tension member or the second tension member being tightly supported on each bracket that is the first support member or the second support member. Reinforcement device of a steel composite bridge characterized in that the tensile force is applied to. The method of claim 1, The first support member or the second support member is a bracket having a tapered fixing hole whose diameter decreases as it proceeds in a direction facing each other, and both ends of the first tension member or the second tension member are respectively provided through the fixing hole. It is fixed to the flange of the steel box girder to pass through, The first tension member or the second tension member is a steel wire, The first pulling means or the second drawing means has a tapered outer circumferential surface corresponding to the taper of the fixing hole, and the first exposed means through the fixing holes of each of the first supporting member or the second supporting member in the center thereof. A wedge-shaped fixing member having a tightening hole for inserting both ends of each of the tension member or the second tension member, wherein the first tension member or the second tension member is inserted into the tightening hole to apply a fixing force. Is gradually entered into and tightened by the fixing hole and supported by the fixing hole so that the first tension member or the second tension member is bitten and fixed by the tightening hole and exerts a tensile force on the first tension member or the second tension member. Reinforcement device of the steel composite bridge characterized in that. The method according to any one of claims 1 to 3, The first tension member is applied with a tensile force for applying a prestress corresponding to the bending moment added by the weight of the slab installed on the upper portion of the steel box girder, The second tension member is a reinforcement device for a steel composite bridge, characterized in that a tensile force is applied to apply a prestress corresponding to the bending moment added due to the live load of the steel composite bridge. The method according to any one of claims 1 to 3, Inside the steel box girder is provided with a diaphragm connected to the upper and lower flanges and the abdominal plate of the left and right sides, The first support member or the second support member is simultaneously connected to the tensioned flange of the diaphragm and the steel box girder at the point where the diaphragm meets the tensioned flange of the steel box girder at the position where the diaphragm is provided. Reinforcement device of steel composite bridge, characterized in that fixed. The method according to any one of claims 1 to 3, Guides fixed to the flanges of the steel box girder provided on the line through which the first tension member or the second tension member pass so that the first tension member or the second tension member passes through the through holes. Reinforcement device of a composite steel bridge further comprising a member. The method according to any one of claims 1 to 3, Reinforcement device of the steel composite bridge, characterized in that the through hole for the first tension member is passed through the second support member. In the construction method of the reinforcement apparatus of the steel composite bridge which constructs the reinforcement apparatus of the steel composite bridge which has a structure of any one of Claims 1-3, Installing the steel box girder on top of the shift and piers, Applying tension to the first tension member to apply prestress corresponding to the bending moment added by the weight of the slab to be constructed on top of the steel box girder; Constructing a slab on top of the steel box girder; And applying a tensile force to apply a prestress corresponding to the bending moment added due to the live load to the second tension member of the steel composite bridge against the dead load of the steel composite bridge.

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