KR20160080869A - Construction method of prestressed steel composite girder bridge - Google Patents

Abstract

Disclosed is a construction method capable of reducing an amount of a steel material used by reducing a stress burden to a steel girder and improving stress efficiency by additionally applying a compressive force to lower casing concrete when manufacturing a prestressed steel composite girder bridge. To achieve this, provided is the construction method of the prestressed steel composite girder bridge including: a step of forming a steel girder assembly; a step of fixating a temporary reinforcing steel plate to an upper flange of the steel girder assembly; a step of installing casing concrete with an anchorage device and a PC steel material in a lower flange of the steel girder assembly; a step of separating the temporary reinforcing steel plate from the steel girder assembly; a step of applying prestress by applying tension to the PC steel material; and a step of placing the steel girder assembly on an abutment and piers. According to the present invention, the stress efficiency can be improved by reducing the amount of the steel material used and additionally applying the compressive force.

Description

Technical Field [0001] The present invention relates to a method of constructing a prestressed steel composite girder bridge in which an additional prestress is introduced by a temporary reinforced steel plate,

The present invention relates to a method of constructing a prestressed steel composite girder bridge that introduces additional prestress using a temporary reinforced steel plate, more particularly, to a method of reducing the stress burden of a steel girder by means of a provisional reinforced steel plate, And a construction method of a prestressed steel composite girder bridge in which a production stand is omitted.

Generally, the concrete has excellent resistance to compressive stress but has very weak resistance to tensile stress. Therefore, when a girder including concrete is manufactured, the tensile strength of the concrete caused by the dead load or live load acting on the girder Stress relieving must be considered.

For this purpose, by introducing compressive stress in advance to the concrete by tensioning and fixing the high strength PC strand to the girder including concrete, it is possible to offset the tensile stress generated in the concrete according to the dead load or live load acting on the girder do.

The prestressed girder (hereinafter abbreviated as "prestressed girder") which introduces the compressive stress by the PC stranded wire is a prestressed concrete girder (hereinafter simply referred to as "prestressed girder" Prestressed concrete composite girder (PSC) girder) and a prestressed steel composite girder (20) in which a steel I-girder having a predetermined rigidity is placed inside a concrete section.

The prestressed steel composite girder is formed by embedding a steel material 21 in the cross section of the concrete 22, as shown in Figs. That is, the I-girder used as the steel material 21, the concrete 22 cured by being placed so as to surround the lower edge of the steel material 21, and the concrete 22 applied at both ends of the concrete 22 A PC strand 23 formed thereon, and a fixture 24 fixing both ends of the PC strand 23.

The prestressed steel composite girder 20 is configured to introduce compressive stress to the concrete 22 only by the tension of the PC strand 23 provided in the concrete 22 without applying bending strain to the steel material 21. [

This prestressed steel composite girder 20 overcomes the mechanical disadvantages of the conventional Precom (PSC) girder, thereby reducing the burden on the weight of the concrete when tension is introduced and enhancing the tension efficiency. At the same time, To reduce the height of the girders (commonly referred to as 'deformations').

However, the prestressed steel composite girder 20 requires an expensive production stand at the time of manufacture, which causes construction cost increase and air delay.

In addition, since four fixing ports can not be arranged on a narrow casing concrete section, a buried type fixing port is embedded in the casing concrete to overcome this. This is because the installation process is very complicated, the settlement condition is incomplete, and the tensions are buried in advance, which may lead to corrosion of the girder during long term storage. In addition, the buried type fixing unit has an ineffective limit in which the maximum fixing force can not be applied in order to prevent damage because the fixing state is relatively incomplete unlike the end fixing unit using the pressure plate and there is a risk of damage in tension.

Korean Patent No. 10-0978463 (published on Aug. 26, 2010) Korean Patent No. 10-1074751 (issued October 18, 2011) Korean Patent Publication No. 10-2013-0028395 (published on Mar. 19, 2013)

Therefore, it is an object of the present invention to provide a method of manufacturing a prestressed steel composite girder, which reduces steel by reinforcing rigid rigidity corresponding to the casing installation, introduces additional compressive force to the lower casing concrete, And to provide a method of constructing a prestressed steel composite girder bridge having improved economy and workability.

In order to accomplish the objects of the present invention, in one embodiment of the present invention, there is provided a method of manufacturing a steel girder assembly, comprising the steps of: preparing a steel girder assembly by arranging a plurality of steel girders in a line and assembling them; A step of installing a casing reinforcing steel plate on a flange in a longitudinal direction of the steel girder assembly, a casing concrete installation step of installing a casing concrete having a fixing port and a PC steel on a lower flange of the steel girder assembly, A preliminary reinforcing steel sheet separating step of separating the reinforcing steel plate from the steel girder assembly, a prestress introducing step of introducing the prestress by tilting the PC steel with the fixing port, and a hypothetical step of alternately mounting the prestressed steel girder assembly on the pier and the pier Of prestressed steel composite girder bridges It provides a public method.

According to another aspect of the present invention, there is provided a method of manufacturing a steel girder assembly, comprising the steps of: preparing a steel girder assembly by arranging a plurality of steel girders in a line and assembling the steel girder assembly; A steel plate mounting step of disposing a temporary reinforcing steel plate in the longitudinal direction of the steel girder assembly to fix the temporary reinforcing steel plate to the upper flange so that the temporary reinforcing steel plate is brought into contact with the lower flange of the casing girder assembly, A temporary reinforcing steel plate separating step of separating the temporary reinforcing steel plate from the steel girder assembly, and a pre-stressed steel plate separating step of separating the temporary reinforcing steel plate from the pre- The assemblies are mounted on alternating and pier Further comprising a step to provide a construction method of the prestressed composite steel girder bridge according to claim.

The present invention can reduce the maximum stress generated in the lower flange of the steel girder when the casing concrete is poured by using the temporarily reinforced steel plate connected to the upper flange of the steel girder, thereby reducing the burden of the lower flange and introducing additional prestress into the casing concrete. In other words, the method of constructing the prestressed steel composite girder bridge according to the present invention can reduce the steel amount and increase the tension efficiency by further introducing the compressive force.

In addition, the present invention omits the use of an expensive manufacturing base and uses a generalized pressure-sensitive fixing member that is sufficiently proven in safety, thereby enhancing economic efficiency, durability, safety, and efficiency, and can also expect a shortening effect of air.

1 is a side view showing the structure of a conventional prestressed steel composite girder.
2 is a cross-sectional view showing the structure of a conventional prestressed steel composite girder.
3 is a flowchart illustrating a method of constructing a prestressed steel composite girder bridge according to an embodiment of the present invention.
4 is a cross-sectional view showing a prestressed steel composite girder provided with a temporary reinforcing steel plate.
5 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to an embodiment of the present invention.
6 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.
7 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.
8 is a flowchart illustrating a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, (Hereinafter referred to as " a method of constructing a prestressed steel composite girder bridge ") in which an additional prestress is introduced by a temporary reinforcing steel plate will be described in detail.

FIG. 3 is a flow chart for explaining a method of constructing a prestressed steel composite girder bridge according to the present invention, and FIG. 4 is a sectional view showing a prestressed steel composite girder provided with a temporary reinforced steel plate.

3, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a steel girder assembly manufacturing step S100 for producing a steel girder assembly 110 constituting a prestressed steel composite girder 100, A temporary reinforcing steel sheet mounting step S200 for mounting and temporarily fixing the temporary reinforcing steel plate 200 on the upper part of the steel girder assembly 110 and a casing concrete installation for installing the casing concrete 120 on the steel girder assembly 110 (S400) for separating the temporarily reinforced steel plate from the steel girder assembly (S400), a prestress introducing step (S500) for tilting the PC steel, and a step of replacing the steel girder assembly into which the pre- And a hypothetical step S600 for mounting on the bridge pier.

As shown in FIG. 4, the prestressed steel composite girder 100 used in the method of constructing the prestressed steel composite girder bridge is installed and cured so as to surround the lower girder of the steel girder assembly 110 and the steel girder assembly 110, A long steel material 130 formed to apply compressive stress to the casing concrete 120 at both ends of the casing concrete 120 and a fastening port 140 for fastening both ends of the long steel material 130 ).

More specifically, the steel girder assembly 110 is assembled after the steel girders are arranged in the same line, and the steel girder includes an upper flange 112, a lower flange 114, and a web 116 connecting these flanges. ≪ / RTI >

At this time, the upper flange 112 is provided on the upper part of the abdomen 116 disposed in the vertical direction, and the lower flange 114 is provided on the lower part of the vertical part 116. The upper flange 112, The lower flanges 114 are arranged to remain horizontal with respect to each other.

In addition, one or more sheath pipes (not shown) may be installed in the casing concrete 120 to insert the PC steel material 130, which is a tension material.

Hereinafter, each step will be described in more detail with reference to the drawings.

5 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to an embodiment of the present invention.

First, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a steel girder assembly manufacturing step (S100).

The steel girder assembly manufacturing step (S100) is a step of arranging a plurality of steel girders in the same line and then assembling them to produce a steel girder assembly 110. This steel girder assembly 110, as shown in FIG. 5, It is preferable that the center is formed so as to be curved in a convex shape.

In this step S100, the contact surfaces of the steel material girder and the steel material girder may be directly welded to each other, or the steel material girder and the steel material girder may be connected by a bolt and a rivet method. In other words, the plurality of steel girders may be connected to each other through physical coupling means such as bolts, or through chemical coupling methods such as welding.

Next, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a provisional reinforced steel plate installing step (S200).

The temporary reinforcing steel plate 200 is disposed in the longitudinal direction of the steel girder assembly 110 so that the temporary reinforcing steel plate 200 is brought into contact with the upper flange 112 and the steel girder assembly 110 And fixing the provisional reinforced steel plate 200 to the upper flange 112 of the upper portion.

In this step, the temporarily-stiffened steel sheet 200 may be fixed by a physical coupling means such as a bolt so as to smoothly separate the upper flange 112 from the upper flange 112 later.

The temporarily reinforced steel plate 200 installed in the prestressed steel composite girder 100 through the provision of the temporary reinforced steel plate 200 reinforces the rigidity of the steel girder assembly 110 when the casing concrete 120 is poured, The first prestress is introduced into the girder 100.

Next, a method of constructing a prestressed steel composite girder bridge according to the present invention includes installing a casing concrete (S300).

The casing concrete installation step S300 includes installing a casing concrete provided with a fixing port 140 and a PC steel member 130 on a lower flange 114 of a steel girder assembly 110 that has passed through a provisional reinforcing steel plate installation step S200 .

As a first embodiment, the casing concrete installation step S300 according to the present invention includes the steps of placing the both ends of the steel girder assembly 110 on both sides of the fabric frame 110 so as to separate the steel girder assembly 110 from the ground, A step of installing a mold 150 in a lower flange 114 of the steel girder assembly 110 and a sheath pipe and a PC steel 130 in the mold 150, And a casing concrete curing process in which the concrete is laid and cured in the mold 150 and then the mold is removed.

At this time, the PC steel material 130 is provided with a fixation port 140 at both ends thereof, and the fixation port is preferably a movable fixation port.

6 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.

As shown in FIG. 6, the casing concrete installation step S300 according to the second embodiment of the present invention includes the first and second supports 510 and 510 spaced from each other on the lower flange 114 of the steel girder assembly 110, A first support structure 510 and a second support structure 510 are installed between the front end of the steel girder assembly 110 and the first support structure 510, 520 and a third formwork 156 is installed between the second support platform 520 and the rear end of the steel girder assembly 110 and the second formwork 154 is installed between the second support platform 520 and the rear end of the steel girder assembly 110, A first PC steel member 132 provided with a pair of fixing holes is disposed inside the first die member 154 and a pair of fixing holes 152 are formed so as to pass through the first die member 152 and the second die member 154 and the third die member 156. [ A PC steel material assembling process for disposing a second PC steel material 134 having a first conical shape and a second conical shape having a second conical shape on the inside of the first and second molds 154, Sikimyeo placing the discrete, and curing the concrete, the concrete curing process may be of a casing having a casing of concrete by removing each die (152, 154, 156).

At this time, the first PC steel member 132 and the second PC steel member 134 are provided at both ends with a fixation hole 140, and the fixation hole is preferably a flexible fixation hole.

In addition, as shown in FIG. 6, the first PC steel member 132 and the second PC steel member 134 may be provided on the same vertical axis (or horizontal line), respectively. More specifically, a pair of first PC steels 132 are preferably disposed between the second PC steels 134 and the second PC steels 134.

Such a fixing method can increase the safety by allowing a movable (fountain-type) fixing port to be disposed in a space to be laid back without using an incomplete fixed (buried) fixing port. After the first PC steel member 132 is firstly tensed, The second PC steel member 134 can be tensed secondarily after the moving installation to compensate for the time loss of the first PC steel member 132 and to adjust the optimal tension point.

7 is a flowchart showing a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.

As shown in FIG. 7, the casing concrete installation step S300 according to the third embodiment of the present invention includes the first and second supports 510 (510) spaced from each other in the lower flange 114 of the steel girder assembly 110, A first support structure 510 and a second support structure 510 are installed between the front end of the steel girder assembly 110 and the first support platform 510, A mold installation process in which a second mold 154 is installed between the first support 520 and the second support 520 and a third mold 156 is installed between the second support 520 and the rear end of the steel girder assembly 110, A first PC steel member 136 having a fixing port is provided so as to pass through the first die 152 and the second die 154 and a second PC steel member 136 having a fixing hole is provided to penetrate the second die 154 and the third die 156. [ A PC steel material assembling process in which the PC steel material 138 is disposed, and a PC steel material assembling process in which concrete is injected into the first and second molds 154, It may be poured, and the configuration sikimyeo curing the concrete, by removing the respective mold (152, 154, 156) into a casing of concrete curing process having a concrete casing.

At this time, both ends of the first PC steel member 136 and the second PC steel member 138 are provided with a fixation port 140, and the fixation port is preferably a movable fixation port.

In addition, the first PC steel member 136 and the second PC steel member 138 may be provided on the same vertical axis (or horizontal line), as shown in FIG. More specifically, one end of the first PC steel member 136 and the other end of the second PC steel member 138 are preferably disposed so as to intersect with each other with respect to the plan view.

Such a fixing method can increase the safety by making it possible to dispose the pressure-sensitive fixing unit in a space to be rearranged without using an incomplete embedded fixing unit.

The construction method as shown in FIG. 6 has the advantage of maximizing the introduction time and efficiency of the tension force, but it has a disadvantage that the construction is delayed somewhat and the construction cost is increased because the tension work is performed twice.

In addition, the construction method as shown in FIG. 7 can be completed and the workability and economic efficiency can be increased.

Next, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a temporary reinforced steel plate separation step (S400).

The temporary reinforcing steel plate separating step S400 is a step of removing the temporary reinforcing steel plate 200 introduced through the temporary reinforcing steel plate installing step S200.

By the removal of the temporary reinforcing steel plate 200, an upward force is generated in the girder assembly 110, so that the compressive force acts on the casing concrete. This can reduce the required torsional strength of the torsion springs and thus reduce the torsion springs.

Continuing, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a prestress introduction step (S500).

The step of introducing the prestress (S500) is a step of introducing a prestress by tilting the PC steel material 130 inside the sheath pipe provided in the casing concrete 120. At this time, as the PC steel material 130, a stranded wire, a piano wire, a special steel wire, or the like may be used, and a stranded wire is preferably used.

As shown in FIG. 6, the prestress introduction step S500 according to an embodiment of the present invention includes a first tensioning process for straining the first PC steel member 132, a first tensioning process for tilting the first PC steel member 132, 2 support platform 520 and a method of placing the concrete between the first formwork 152 and the second formwork 154 and between the second formwork 154 and the third formwork 156 And a secondary tension process to tension the second PC steel member 134. The second PC steel member 134 may be formed of a hardening material, At this time, the positions of the first support 510 and the second support 520 moved through the process of moving the support are preferably the leading and trailing ends of the steel girder assembly 110, respectively.

As described above, according to the present invention, two movable fastening openings, which are generally used, can be disposed at both ends of the steel girder assembly 110, and two movable fastening openings can be arranged in the middle, .

In addition, although the first and second tension structures have a disadvantage in that the construction is somewhat cumbersome due to the tension being applied twice, it is possible to adjust the second tension period to suit the field conditions, thereby providing an optimum stress state .

In another embodiment, the step of introducing a prestress according to the present invention (S500) includes a step of moving a position of the first support 510 and the second support 520, as shown in FIG. 7, A filling process in which concrete is poured and cured between the first and second molds 152 and 154 and between the second and the third moldings 154 and 156; The first PC steel member 136 and the second PC steel member 138 may be tensed through the fixing holes exposed to the first fixing member 136 and the second fixing member 138, respectively. At this time, since the movable fixation port disposed inside the steel girder assembly 110 is embedded and fixed in the concrete through the embedding process, it provides the function of the fixed fixation port.

This single tension structure has the advantage of being able to proceed the construction as quickly as all the tension work is ended at once.

If necessary, the temporary reinforcing steel plate separating step (S400) and the prestress introducing step (S500) may be alternately performed.

8 is a flowchart illustrating a method of constructing a prestressed steel composite girder bridge according to another embodiment of the present invention.

Referring to FIG. 8, in the method of constructing a prestressed steel composite girder bridge according to the present invention, the above-described pre-stress introduction step (S350) may be performed before the provisional reinforced steel plate separation step (S400).

As described above, when the temporary reinforcing steel sheet 200 is separated after the introduction of the prestress, a part of the prestress loss can be recovered. Therefore, there is an advantage that more additional tension can be introduced and the operation is somewhat complicated There is a drawback.

On the contrary, when the cross-section is sufficient and the additional tension is not required to be large, it is preferable to shorten the air by improving the workability by removing the temporary reinforcing steel plate 200 together with the mold before the introduction of the prestress.

Finally, a method of constructing a prestressed steel composite girder bridge according to the present invention includes a hypothetical step S600.

The hypothetical step (S600) is a step of placing the prestressed steel composite girder (100) on which the prestress is introduced through the prestress introduction step (S600).

If necessary, the method of constructing a prestressed steel composite girder bridge according to the present invention may further include a step of placing a concrete slab.

The step of placing the concrete slab is a step in which concrete is placed and cured on the upper surface of the prestressed steel composite girder 100 mounted on the alternation and pier through the hypothetical step S600 to install the concrete slab on the prestressed concrete girder .

At this time, the height of the concrete slab is not limited because the height of the concrete slab can be variously modified so as to form a proper thickness to the required load of the bridge.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the appended claims. It can be understood that it is possible.

100: Prestressed steel composite girder 110: Steel girder assembly
120: casing concrete 130: PC steel
132, 136: first PC steels 134, 138: second PC steels
140: Fixture 150: Formwork
200: Temporary reinforcement steel plate 400: Both side frames
510: first support 520: second support

Claims (7)

A steel girder assembly manufacturing step of arranging a plurality of steel girders in the same line and assembling them to produce a steel girder assembly;
A temporary reinforcing steel plate mounting step of disposing a temporary reinforcing steel plate in a longitudinal direction of the steel girder assembly so as to be in contact with an upper flange of the steel girder assembly and fixing the temporary reinforcing steel plate to the upper flange;
A casing concrete installation step of installing a casing concrete having a fixing port and PC steel on a lower flange of the steel girder assembly;
A temporary reinforcing steel plate separating step of separating the temporary reinforcing steel plate from the steel girder assembly;
A prestress introduction step of introducing a prestress by tentering the PC steel with the fixing means; And
A method of constructing a prestressed steel composite girder bridge including a step of placing a steel girder assembly incorporating a prestress over alternating and piercing. The method according to claim 1, wherein the casing concrete installation step
A support stand installation step of installing first and second supports spaced apart from each other on a lower flange of the steel girder assembly,
A first formwork is provided between the front end of the steel girder assembly and the first support, a second formwork is provided between the first and second supports, and a third formwork is provided between the second support and the rear end of the steel girder assembly. A mold installation process for installing the mold,
A first PC steel member having a pair of fixing holes is disposed in the second die, and a second PC steel member having a pair of fixing holes is disposed so as to penetrate the first die, the second die and the third die PC steel assembly process,
And a casing concrete curing step of pouring concrete into the first, second, and third dies, curing the concrete, and removing each form to provide a casing concrete. Construction method of girder bridge. 3. The method of claim 2, wherein the step of introducing a prestress
A first tensioning step of tensioning the first PC steel,
A support moving step of moving the positions of the first support and the second support,
A primary PC steel landfill process in which concrete is poured and cured between the first and second molds and between the second and third molds, and
And a second tensional process of tilting the second PC steel. ≪ RTI ID = 0.0 > 8. < / RTI > 3. The method of claim 2, wherein the fixture is a movable fixture. The method according to claim 1, wherein the casing concrete installation step
A support stand installation step of installing first and second supports spaced apart from each other on a lower flange of the steel girder assembly,
A first formwork is provided between the front end of the steel girder assembly and the first support, a second formwork is provided between the first and second supports, and a third formwork is provided between the second support and the rear end of the steel girder assembly. A mold installation process for installing the mold,
A PC steel assembly process for disposing a first PC steel member having a fixing port to penetrate through the first and second molds and a second PC steel member having a fixing port for passing through the second and third molds;
And a casing concrete curing step of pouring concrete into the first, second, and third dies, curing the concrete, and removing each form to provide a casing concrete. Construction method of girder bridge. 6. The method of claim 5, wherein the prestressing step
A support moving step of moving the positions of the first support and the second support,
A landfill process in which concrete is poured and cured between the first and second molds and between the second and third molds, and
And a tensioning step of tensioning the first PC steel material and the second PC steel material through the fixing holes exposed at both ends of the steel girder assembly. A steel girder assembly manufacturing step of arranging a plurality of steel girders in the same line and assembling them to produce a steel girder assembly;
A steel plate mounting step of disposing a temporary reinforcing steel plate so as to be in contact with an upper flange of the steel girder assembly in the longitudinal direction of the steel girder assembly and fixing the temporary reinforcing steel plate to the upper flange;
A casing concrete installation step of installing a casing concrete having a fixing port and PC steel on a lower flange of the steel girder assembly;
A prestress introduction step of introducing a prestress by tentering the PC steel with the fixing means;
A temporary reinforcing steel plate separating step of separating the temporary reinforcing steel plate from the steel girder assembly; And
Further comprising a step of placing the steel girder assembly having the prestress introduced thereon alternately and over the pier. ≪ RTI ID = 0.0 > 8. < / RTI >

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