KR101104297B1 - Preflex girder making method and bridge construction method using the same - Google Patents

Abstract

PURPOSE: A manufacturing method and a manufacturing method of short-span and multi-span pre-flex girders are provided to manufacture a precise pre-flex girder by easily controlling vertical and horizontal displacement during a manufacturing process. CONSTITUTION: A manufacturing method of short-span and multi-span pre-flex girders is as follows. A steel beam(200) is installed in a manufacturing board. The manufacturing board comprises end frames(300) and steel bam positioning units(400). The end frames cover both ends of the steel beam. The steel bam positioning units are arranged on the inner side of the end frames. Pre-flexion is applied to the steel beam. Casing concrete is formed in the steel beam using a casing form. Pre-stress is applied to the casing concrete by removing the pre-flexion.

Description

Preflex girder manufacturing method and short span and multi span preflex girder construction method {PREFLEX GIRDER MAKING METHOD AND BRIDGE CONSTRUCTION METHOD USING THE SAME}

The present invention relates to a method for manufacturing a preflex girder and a method for constructing a short span and a multi span preflex girder. More specifically, it is possible to introduce more stable and precise preflection in the preflex girder manufacturing industry and to manufacture and construct a preflex girder that can be manufactured economically.

In general, preprex girders are a composite girder made by mixing the characteristics of steel and the advantages of concrete, and these girders are applied with preflection by applying a load to both sides of the girder manufactured in an upward camber state. After curing by pouring concrete to the lower flange of the fabric, it is manufactured by removing the preflection applied to the girder.

Such preprex girders are installed to act as beams when constructing a structure such as a bridge or a building, and are particularly used where a span is relatively long. 1 is a view showing a manufacturing apparatus used to manufacture a conventional general preflex girder,

Typically, two preflex girders having a predetermined length are produced simultaneously.

The manufacturing apparatus for manufacturing such a preflex girder is provided with two rows of posts 100 installed at constant intervals and distances facing each other, and predetermined positions (approximately L / 4 points) on both sides of each row of posts 100. A plurality of stands 102 installed at the upper and lower ends of the upper girder G1 and the lower girder G2 that form the mother of the preflex girder;

The upper rail 108 is installed in the horizontal direction to the support 104 is fixed to the upper inner side of the post 100 of each row to support the upper formwork 106 and on the inner bottom surface of the post 100 of the row It is installed includes a lower rail 112, the lower formwork 110 is supported.

The upper girder G1 is fixed to the stand 102 by a turnbuckle 114 connected to the stand 102 in a state where the upper girder G1 is mounted on the stand 102, and the lower girder G2 has a turnbuckle connected to the stand 102 at one side thereof. 116) is fixed by hanging.

The upper formwork 106 is installed on the upper flange portion of the upper girder (G1), the lower formwork 110 is installed on the lower flange portion of the lower girder (G2) as shown in the figure.

The upper and lower dies 106 and 110 are supported on the upper and lower rails 108 and 112 by the support members 118 provided on both lower sides thereof, respectively, to maintain the installed state.

The support member 118 is provided with a screw jack 120 is adjustable in length to restrain the upper, lower die 106, 110 to move from side to side.

In order to manufacture a preflex girder using such a preflex girder manufacturing apparatus, first, the upper girder G1 and the lower girder G2 are mounted on the stand 102 so that the cambered portions face each other, or the turnbuckle ( Fix it to the stand 102 using 114, 116.

Then, both ends of the upper girder G1 and the lower girder G2 are pressurized in the vertical direction by using a hydraulic jack or the like to stress the girder, and the upper girder G1 and the lower girder G2 one side flange Assemble and install the upper and lower dies 106, 110 in the part,

After the casing concrete (C) is poured and cured, respectively, the upper and lower dies 106 and 110 are removed and the stress applied to the girder is removed to complete the preparation of the preflex girder.

The upper girder (G1) and the lower girder (G2) thus manufactured are separated from the production apparatus by using a crane, etc., then transported to the installation site by means of transportation, and then installed, and then slab is installed on the upper part of the section. To build bridges and structures.

However, the conventional preflex girder fabrication apparatus as described above has a problem that the cost of equipping the production site and equipments is very large as a very large facility, and the preflex girders are placed up and down to make the long preflex In manufacturing the girder, the actual vertical and horizontal displacement is too large in the manufacturing process, so even if the support member 118 for controlling the position of the upper and lower girder is used, the accuracy of introducing the required preplex may be inferior. There was only.

Therefore, the present invention can minimize the conventional preflex girder manufacturing facilities, while ensuring sufficient economic feasibility, even if vertical and horizontal displacement occurs in the manufacturing process, it is easy to control the preflex girder that can produce a more precise preflex girder Providing a manufacturing method is the technical problem to be solved.

In order to achieve the above technical problem, in setting the steel beam in the manufacturing apparatus or the manufacturing table in the manufacturing process, the end frame and the air or the end frame which can easily control the horizontal and vertical displacement of the steel beam when concrete load Steel beam position adjusting device for adjusting the horizontal and vertical degree of the steel beam by the hydraulic pressure is used.

To this end,

Installing a steel beam on a workbench and then applying a preflection to the steel beam; Forming a casing concrete by using casing dies on the steel beam; In the pre-plex composite beam fabrication method comprising a; and the step of removing the pre-plexing to introduce pre-stress to the casing concrete;

The fabrication table is to prevent the position is changed by the pre-flexion acting on the steel beam

An end frame installed to surround both ends of the steel beams such that both ends of the steel beams are constrained in horizontal and vertical directions; And

It is provided inside the end frame and the steel beam positioning device for adjusting the horizontal and vertical degree of the steel beam by the air at the bottom of the steel beam; provides a preflex girder manufacturing method comprising a.

Also preferably

The steel beam provides a preflex girder manufacturing method for installing at least one central support comprising a lower support for supporting the upper support from the bottom and a bottom support of the inverted "b" shape supporting the downwardly curved steel beam. do.

Also preferably

 The step of applying the pre-fraction

After the steel beam is manufactured to form an upward camber, the steel beam is turned upside down and installed in the end frame in a downward curved state.

When the casing concrete is cured in the casing formwork installed to cover the upper part of the downwardly curved steel beam, the casing formwork is dismantled to generate elastic resilience force of the steel beam deflected downward by the weight of the casing formwork, thereby compressing prestress naturally to the casing concrete. Is introduced,

It provides a method for manufacturing a preflex girder comprising the step of separating the preplex composite beam from the fabrication table and upside down.

In other words, if the casing concrete is cured in the casing form formed to cover the upper portion of the downwardly curved steel beam, the casing form is removed when the casing form is dismantled, and thus the steel girder is released.

That is, the deflection occurs downward by the weight of the casing formwork, and when the casing formwork is dismantled, elastic restoring force of the steel girder is generated so that the compression prestress is naturally introduced into the casing concrete.

Also preferably

The step of applying the pre-fraction

After the steel beam is manufactured to form an upward camber, the steel beam is turned upside down and installed in the end frame in a downward curved state.

A casing concrete is formed to cover the upper portion of the downwardly curved steel beam to manufacture a preflex composite beam,

It provides a method of manufacturing a preflex girder comprising the step of separating the prepared preplex composite beam from the fabrication table upside down.

Also preferably

After separating the fabricated preflex composite beam from the fabrication stage and then upside down and disposed,

It provides a preflex girder manufacturing method further comprising the step of introducing the prestress to the casing concrete using a post tension tension material disposed inside the casing concrete of the preflex composite beam.

Also preferably

The end frame is a bottom plate installed on the bottom of the production site; And two vertical side wall plates which are set to face each other on an upper surface of the bottom plate. And a vertical finishing plate on the front and rear surfaces of the airbag to provide a preflex girder manufacturing method in which steel beam positioning devices are installed in both vertical side wall plates.

Also preferably

The steel beam positioning device

Airbags installed in both vertical sidewall plates;

A hose connected to the air bag, the compressor being capable of injecting or discharging air;

A discharge hose for discharging the air injected into the air bag;

The air bag inside the partition wall;

Provided is a method for manufacturing a preflex girder comprising a supporter including an upper bent plate corresponding to a curved shape at both ends of the downwardly curved steel beam and a support frame installed below the upper bent plate.

Also preferably

Installing the fabricated preplex composite beam (primary preflection introduced) in the bridge substructure; And

Forming a coated concrete on the upper flange and the abdomen of the preplex composite beam;

Forming a slab on top of the preplex composite beam; And

It provides a short-span preflex girder construction method comprising the step of introducing a compression prestress (secondary pre-flection introduced) to the casing concrete using a tension material disposed inside the casing concrete of the preflex composite beam installed in the bridge substructure. .

Also preferably

Installing the fabricated preplex composite beam (primary preflection introduced) in the bridge substructure; And

Forming a coated concrete on the upper flange and the abdomen of the preplex composite beam;

The preplex composite beams are continuously connected to each other in the longitudinal direction by using the branch connecting member 900, wherein the branch connecting member 900 is an upper flange of the steel beam 200 exposed to the connecting member of the "inverted c" shape. Inserting into the abdomen and the lower flange and fixing the "inverted U-shape" type of connecting material to the exposed abdomen 220 of the girder with fasteners such as connecting bolts and nuts to be installed in the steel beam 200;

Forming a slab on top of the preplex composite beam; And

It provides a multi-span preflex girder construction method comprising the step of introducing a compressive prestress (secondary preflection introduced) to the casing concrete using a tension material disposed inside the casing concrete of the preflex composite beam installed in the bridge substructure. .

The present invention enables the production of more precise and economical preflex girders using a simple equipment.

This makes it easier to manufacture preflex girders without the need for complex and large-scale production facilities.

As a result, the present invention is to maintain a stable setting in the process of setting the steel beam, it is possible to manufacture a very efficient and economical preflex girder because it does not use a separate loading device for pre-loading loading.

In addition, short span and multi span bridge construction can be performed using the preflex girder of the present invention.

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

1 is a detailed view of a conventional preflex girder fabrication table,
Figures 2a, 2b and 2c is a manufacturing plan of the preflex girder according to the present invention.
3a and 3b is a construction of a short span bridge construction according to the present invention.
Figure 4 is a multi-span (continuous bridge) bridge construction of the present invention.

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

Hereinafter, a preflex girder fabrication model will be described based on FIGS. 2A to 2C.

First, the steel beam 200 is manufactured as shown in FIG. 2A, which has a cross-section formed into an I-type upper flange 210, an abdomen 220, and a lower flange 230.

In addition, the steel beam 200 is manufactured to have a predetermined length in a built-up (BUILT-UP) manufacturing method.

At this time, the lower flange 230 is preferably to produce a steel beam 200 smaller than the transverse width of the upper flange 210.

The steel beam 200 is pre-determined in the cross section to have an upward camber (CAMBER) in the longitudinal direction, the degree of the upward camber is the amount of the preflex girder (steel beam + casing concrete + casing formwork) of a straight line in the longitudinal direction. When the end is set in the form of a simple support, it is preferable to have an upward camber corresponding to the deflection value by its own weight.

Accordingly, in FIG. 2A, it can be seen that an up camber which has an up displacement δ corresponding to the deflection value is formed.

This may be regarded as securing the prestress to be introduced into the casing concrete by the pre-loading load and the elastic restoring force of the steel beam.

Next, the steel beams 200 are placed upside down on the end frame 300 installed to cover and support both ends of the steel beams 200 in which the up cams are formed.

Thus, in the upside down state, it can be seen that the upper flange 210 of the steel beam 200 in which the up camber is formed is set as the lower flange, and the lower flange 230 is set as the upper flange.

At this time, the role of the end frame 300 is to restrain the position while supporting the steel beam 200 to be disposed upward from the bottom will be said to correspond to the support member 180 in Figure 1 functionally.

This end frame 300 is

A bottom plate 310 installed at the bottom of the production site; And both vertical side wall plates 320 set to face each other on the upper surface of the bottom plate, but manufactured using a steel plate, but the end frames 300 may be spaced apart from each other in the longitudinal direction at the bottom of the fabrication site.

At this time, the steel beam position adjusting device 400 for adjusting the horizontal and vertical degree of the steel beam by the air or hydraulic pressure of the present invention is installed in the inner space (S) by the two vertical side wall plate 320 and the bottom plate 310 do.

For example, an air bag 410 and a hose 420 connected to the air bag may be used to inject or discharge air.

In other words, the air is injected into the airbag 410 using the compressor 430, and the air can be discharged through the discharge hose 440.

The airbag 410 is inserted into the inner space (S) by the two vertical side wall plate 320 and the bottom plate 310 may be set in a form suitable for the inner space.

Preferably, the vertical finish plate 330 is mounted on the front and rear surfaces of the airbag 410 to set the position of the airbag.

When the airbag 410 is installed, the airbag 410 expands or contracts as air is injected or discharged. Since both side portions of the airbag are blocked by the vertical side wall plate 320, it can be seen that the expansion and contraction of the airbag is controlled in the vertical direction.

In addition, the inside of the airbag 410, the partition wall 450 is further formed by adjusting the amount of air injected into each airbag 410 divided by the partition wall 450 to the fine direction of the airbag 410 by the partition wall Adjustment was possible.

The upper portion of the airbag 410 is further provided with a support 460 so that the contact area between the airbag 410 and the steel beam 200 is uniformly formed.

The support 460 forms an upper bent plate 461 and a support frame 462 provided below the upper bent plate 461 at both ends of the downwardly curved steel beam 200. It is preferable to form the support frame 462 in contact with the upper surface of the airbag 410.

Therefore, both ends of the steel beam 200 are inserted between the two vertical side wall plate 320 from the top.

At this time, the bottom surface of both ends of the steel beam 200 is set in contact with the upper bent plate 461 of the support 460 is set.

Even when the steel beam 200 is seated on the end frame 300 as described above, when the steel beam 200 having a longitudinal length considerably extended is installed, the center portion of the steel beam 200 is not supported. The central lower part of the center pedestal 500 is installed to enable a stable steel beam 200 setting.

The central support 500 is preferably composed of an inverted “b” shaped upper support 510 supporting the downwardly curved steel beam 200 and a lower support 520 supporting the upper support 510 from the bottom. Do.

As a result, it can be seen that the present invention places great importance on the stable setting of the steel beam 200. This is because the self-weight and the pouring load are very large when the casing die 600 and the casing concrete 240 are to be described later. It may be said that the vertical and horizontal displacements of the steel beams 200 do not affect the setting of the steel beams 200.

The longer the longitudinal extension of the steel beam 200 is, the longer the horizontal displacement, the vertical displacement will occur due to its own weight, etc. These displacements are very unstable and accurate because of the deviation from the initial setting of the steel beam 200. It can only be an obstacle to its introduction.

Furthermore, it is preferable to install two or more center pedestals 500 when manufacturing the preflex girders between the limbs.

Basically, by adjusting the position, the number, etc. of the end frame 300, the steel beam positioning device 400 and the central support 500 to accurately set the displacement of the steel beam 200.

At this time, when the steel beam 200 is seated on the steel beam position adjusting device 400 in the end frame 300 so that the upper flange is positioned above the end frame casing die for placing the casing concrete on the upper flange ( 600) to facilitate the installation.

Accordingly, as shown in FIG. 2B, first, the tension sheath inserting sheath 610 and the reinforcing bar assembly 620 are first set around the upper flange, and the casing formwork 600 is wrapped around the upper portion of the steel beam so as to be positioned inside the sheath and the reinforcing bar assembly. Will be installed.

The casing die 600 is installed to be supported by the lower portion of the steel beam 200 by the primary pre-flection support 630 of FIG. 1 so that the weight of the casing die 600 and the casing concrete 240 is the steel beam 200. Will be delivered directly to).

The primary pre-flexion support 630 is preferably made of a member that can be adjusted in length by the rotation of the rotation handle in the middle using a tubular member. This is to adjust the length so that it can be easily supported when there is a change in the installation position of the casing die 600.

As a result, the weight of the tension sheath inserting sheath 610, the reinforcing bar assembly 620, and the casing die 600 has a function of sagging the steel beam 200 downward so that a kind of preflection load is made. .

Next, concrete (C) is poured into the casing formwork 600 so that the sheath and the reinforced assembly are buried, so that the casing concrete 240 having a rectangular spherical shape is formed around the upper flange.

This casing concrete 240 is quite large in weight. This may have the effect that the sufficient reflection on the steel beam 200 is loaded.

In the pre-loading process, the steel beam 200 is forced to generate horizontal displacement and vertical displacement. These displacements are out of the initial setting state of the steel beam 200, and thus, become very unstable and prevent the introduction of the accurate pre-flexion.

Accordingly, the vertical and horizontal displacement of the steel beam 200 in the installation process of the casing formwork, the casing concrete can be basically controlled by the end frame 300.

This is possible because both ends of the steel beam 200 are inserted into the end frame to sufficiently restrain the position of the steel beam 200.

In addition, when a difference occurs in the vertical displacement and the horizontal displacement of the steel beam 200, in order to control the additional amount of air injected into the airbag 410 is adjusted so that the displacement of the steel beam 200 does not occur.

The vertical and horizontal displacement of the steel beam 200 may be used using a horizontal system, not shown.

Although not shown, the steel beam of the present invention can be set in a very stable manner, and the tensioning material for pretension is further installed around the upper flange of the steel beam 200 in advance, and the pretension is applied to the casing concrete 240 having a rectangular spherical shape. This is because the steel beam of the present invention is set to a position close to the floor and stable setting is possible by the end frame, etc., because the tension, release and installation of the pretension tension material is sufficiently possible.

Next, as shown in FIG. 2C, when the casing concrete 240 is cured, the casing die 600 is dismantled. When the casing die 600 is dismantled, since the die weight is removed, the casing die 600 has the effect of releasing the steel beam 200.

That is, the deflection occurs downward by the weight of the casing die 600, and when the casing die is dismantled, elastic restoring force of the steel beam 200 is generated so that the compression prestress is naturally introduced into the casing concrete.

As such, when the casing concrete 240 is formed in the upper flange, the pre-flection girder A is manufactured in the manufacturing table.

Next, using a lifting device, such as a crane not shown, when the pre-flection girders A are lifted up and down again and set up, the lower flange on which the casing concrete 240 is formed is the upper flange 210, and the upper flange is the lower flange. It can be seen that it is set to the flange 230.

Furthermore, the coated concrete (B) is pre-poured on the abdomen and the upper flange of the exposed steel beam of the pre-glare girder (A) to complete the final fold girder (A), the coated concrete as shown in FIG. It may be formed after installation in the structure.

In addition, by inserting a tension member 700, such as a PC strand, into the sheath 610 disposed on the casing concrete 240 of the pre-girder girder (A) to be fixed after the tension on the end surface of the casing concrete after tension, compression to the final casing concrete The prestress is introduced, and of course, all or part of the compressive prestress by the tension member may be introduced after installation in the bridge substructure.

In this case, it can be seen that the preflection girder (A) of the present invention is completed, and in the case of the compression prestress introduced into the casing concrete according to the preflection load,

First, when the casing formwork, sheath, reinforcing bar assembly, casing concrete is placed and cured in the steel beam, when the casing formwork 600 is dismantled,

Second, when the compression prestress by the pre-tensioning tension material introduced into the casing concrete in the manufacturing table dismantles the casing die 600, by the elastic restoring force of the steel beam,

Third, when lifting the Pre-Flation Girder (A) from the workbench and turning it upside down

Fourth, it can be seen that the compression prestress is introduced into the casing concrete of the mounted pre-flexion girders (A) using a post tension tension material.

Thus, the pre-fraction separated from the fabrication table and introduced up to the upside-down process may be referred to as the primary pre-fraction and the secondary pre-fraction introduced through the bridge substructure.

As such, the present invention refers to the tubular member supporting the casing formwork 600 in particular as the primary preflection support 630.

Therefore, it can be seen that it is possible to sufficiently secure the economics of the fabrication equipment because it does not need to separately provide a pre-loading device necessary in the manufacturing process of the conventional preflection girder.

<Short Span Bridge Construction Method Using Preflection Girder A of the Present Invention>

When the pre-flexion girders (A, primary pre-induction) of the present invention is completed in the manufacturing table, the upper and lower sides of the pre-constructed bridge lower structure 800 as shown in FIG.

Next, as shown in FIG. 3b, the bridge is completed by constructing the slab (C) on the preflection girder (A),

By inserting a tension member 700a, such as a PC strand, into the sheath 610 disposed on the casing concrete 240 of the preflation girder A so as to settle after tension on the end surface of the casing concrete after tension, additional prestress to the casing concrete ( Secondary pre-fraction) is introduced.

In addition, some of the tension member (700b) can be drawn out from the upper surface of the casing concrete can be settled after the tension for future maintenance.

As such, it can be seen that the tension members 700: 700a and 700b of the present invention can be disposed in a straight shape inside the casing concrete so as to be fixed after tension on the casing concrete end surface or to be pulled out from the upper surface of the casing concrete. .

In addition, the abdomen and the upper flange exposed to the outside in the pre-girder girder (A) is not shown, but as shown in Figure 4 to form a coated concrete (B) it can be seen that the steel beam is exposed to the outside to prevent corrosion. In addition, it can be seen that the shear connection material is further installed on the upper flange upper surface to protrude upward from the coated concrete.

In addition, the tension material is tensioned and fixed at each stage of manufacture and construction (introduced 1st and 2nd preflection), thereby making it possible to manufacture an efficient preflection girder.

<Multi-Span Bridge Construction Method Using Preflection Girder A of the Present Invention>

4 illustrates a method for constructing a bridge over two spans. In the multi-span bridge, that is, a continuous bridge, the preflex girders A installed in the bridge substructure must be connected to each other.

To this end, in the present invention, both ends of the preflex girder (A) in the branch portion (pier, 810) is exposed to the upper flange, the abdomen of the steel beam, but the casing concrete surrounding the lower flange also excludes a certain length of the lower flange It can be exposed and it can be manufactured by adjusting the extension length of casing formwork.

The preflex girder A is connected to the preflex girder A by the point connecting member 900 in a state where the end faces are in contact with each other in the point portion, and the preflex girder A The coated concrete B is formed in advance on the abdomen 220 and the upper flange 230 of the exposed steel beam.

At this time, the branch connection member 900 is inserted into the upper flange, the abdomen and the lower flange of the steel beam 200 of the "inverse c-shape" form of the exposed member and the "reverse c-shape" of the connector in the exposed form of the girder By fastening fasteners such as connecting bolts and nuts to the abdomen 220, the steel beams 200 can be continuously connected to each other.

In addition, the upper flange of the girder girder is to be surely connected to each other by using the backing plate 910.

The steel beam in the point portion may be continuous with each other by the point connecting member 900, but the shape of the steel beam can be formed in a very advantageous reinforcement structure such as bending parent moment, buckling, etc. acting on the steel beam in the point portion. Able to know.

In this way, when the steel beam is made continuous by the branch connecting member 900, the concrete portion 920 is further placed on the exposed lower flange of the final elongation girder so that the final casing formwork is also continuous in the branch portion.

Of course, when the pre-flexion girders of the present invention (A, 1st pre-introduction) is completed in the fabrication platform, it is mounted on the bridge lower structure 800, which is previously constructed, so that both ends are supported.

Next, to complete the bridge by installing a slab (C) on the pre-flection girder (A),

By inserting a tension member 700a, such as a PC strand, into the sheath 610 disposed on the casing concrete 240 of the preflation girder A so as to settle after tension on the end surface of the casing concrete after tension, additional prestress to the casing concrete ( Second pre-fraction) is the same.

In addition, some of the tension member (700b) can be drawn out from the upper surface of the casing concrete can be settled after the tension for future maintenance.

200: steel beam
210: upper flange 220: abdomen
230: lower flange 240: casing concrete
300: end frame
310: bottom plate 320: both vertical side wall
330: vertical finish plate
400: steel beam positioning device
410: airbag 420: hose
430: compressor 440: discharge hose
450: bulkhead 460: support
500: center stand
510: upper stand 520: lower stand
600: casing dies
610: sheath 620: rebar assembly
630: primary preflection support
700,700a, 700b: tension material
800: bridge undercarriage
900: branch connection member 910: backing plate
920: branch concrete

Claims (9)

Installing a steel beam (200) on a workbench and then applying a preflection to the steel beam; Forming a casing concrete 240 using the casing die 600 in the steel beam; In the pre-plex composite beam fabrication method comprising a; and the step of removing the pre-plexing to introduce pre-stress to the casing concrete;
The production stand
An end frame 300 installed to surround both ends of the steel beam 200; And a steel beam positioning device 400 disposed inside the end frame.
The end frame 300 is the bottom plate 310 is installed on the bottom of the production site; And both vertical side wall plates 320 set to face each other on the bottom plate upper surface. And a vertical finishing plate 330 on the front and rear surfaces of the airbag 410, so that the steel beam positioning device 400 is installed inside the vertical side wall plate 320,
The steel beam positioning device 400 is an air bag 410 installed inside the vertical side wall plate 320; A hose 420 connected to the air bag, to which a compressor 430 for injecting or discharging air is connected; A discharge hose 440 for discharging the air injected into the air bag 410; Inside the air bag 410, the partition wall 450; A support tool 460 including an upper bending plate 461 corresponding to a curved shape at both ends of the downwardly curved steel beam 200 and a support frame 462 installed below the upper bending plate 461. Preflex girder manufacturing method characterized in that it comprises a. The method of claim 1,
The steel beam 200 includes an upper stand 510 having an inverted “a” shape for supporting the downwardly curved steel beam 200 and a lower stand 520 for supporting the upper stand 510 from the bottom. Method of manufacturing a preflex girder, characterized in that at least one installation of the central support (500). The method of claim 1, wherein applying the prefraction
After the steel beam is manufactured to form an upward camber, upside down and installed in an end frame 300 in a downward curved state,
When the casing concrete 240 is cured in a casing formwork installed to cover the upper portion of the downwardly curved steel beam, the casing formwork 600 is dismantled to deflect downward by the weight of the casing formwork 600. Elastic restoring force is generated so that compression prestress is naturally introduced into the casing concrete,
And separating the preplex composite beam from the fabrication table and upside down to arrange the preplex girder beam. The method of claim 1, wherein applying the prefraction
After the steel beam is manufactured to form an upward camber, upside down and installed in an end frame 300 in a downward curved state,
A casing concrete is formed to cover the upper portion of the downwardly curved steel beam to manufacture a preflex composite beam,
Prefab girder manufacturing method comprising the step of separating the prepared preplex composite beam from the fabrication stand upside down. The method according to claim 3 or 4,
After separating the fabricated preflex composite beam from the fabrication stage and then upside down and disposed,
And a step of introducing a prestress into the casing concrete using a post-tensioning tension member disposed inside the casing concrete of the preflex composite beam. delete delete Installing the preplex composite beam fabricated in accordance with claim 1 on a bridge substructure; And
Forming a coated concrete on the upper flange and the abdomen of the preplex composite beam;
Forming a slab on top of the preplex composite beam; And
A short span preflex girder construction method comprising the step of introducing a compression prestress into the casing concrete using a tension material disposed inside the casing concrete of the preflex composite beam installed in the bridge substructure. Installing the preplex composite beam fabricated in accordance with claim 1 on a bridge substructure; And
Forming a coated concrete on the upper flange and the abdomen of the preplex composite beam;
The preplex composite beams are continuously connected to each other in the longitudinal direction by using the branch connecting member 900, wherein the branch connecting member 900 is an upper flange of the steel beam 200 exposed to the connecting member of the "inverted c" shape. Inserting into the abdomen and the lower flange and fixing the "inverted U-shape" type of connecting material to the exposed abdomen 220 of the girder with fasteners such as connecting bolts and nuts to be installed in the steel beam 200;
Forming a slab on top of the preplex composite beam; And
And a compressive prestress is introduced into the casing concrete using a tension member disposed inside the casing concrete of the preflex composite beam installed in the bridge substructure.

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