KR20150051706A - Method for Manufacturing Prestressed Members without Prestressing Bed - Google Patents

Abstract

The present invention is a pretension method, wherein a tensile fore is applied to a tendon such as a PS steel wire, a PS strand, or a PS steel rod, concrete is placed on the stressed tendon, tensile stress of the tendon is released slowly after the concrete is harden, and the concrete is pre-stressed. More specifically, the present invention is a method manufacturing a pre-stressed composite beam without a pre-stressing bed functioning a mold for the composite beam which is pre-stressed. A method manufacturing a pre-stressed composite beam without a pre-stressing bed according to an embodiment of the present invention includes: a first step of arranging an upper flange, a lower flange which is parallel to the upper flange at intervals and has a width larger than a width of the upper flange, steel beams arranged vertically to the upper flanges and lower flanges, wherein webs connecting the steel beams have each an asymmetry section of an H-shape, jointing plates coupled to both ends of the steel beam, end mounting plates installed in center of the steel beam, having a distance from the jointing plates, respectively, and direction changing units between the end mounting plates at the steel beam; a second step of arranging tendons in such a manner that the tendons are curved by the direction change unit and pass through end mounting plates and the jointing plates and giving tension to the tendons; a third step of installing molds at both sides in a width direction of the lower flange of the steel beam to be vertical to the lower flange, placing concrete in the space between each end mounting plate and each mold, and curing the concrete to secure required strength of the concrete; and a fourth step of applying compressed pre-stress through the tendons attached to the concrete by releasing tension of the tendons and cutting the tendons outside of the end mounting plate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a prestressed composite belt,

The present invention relates to a pre-tensioning method for introducing a prestress into a concrete by pouring concrete under tension by applying a tensile force to a prestressing material such as a PS steel wire, a PS strand or a PS steel bar, and slowly releasing the tensile force of the prestressing material after the concrete is cured. The present invention relates to a method of manufacturing a prestressed composite beam without a prestressing bed serving as a formwork of a composite beam into which the prestressed composite beam is introduced.

A prestressed concrete structure is used to compensate the tensile stress by applying compressive stress in the member in advance by using a PS steel wire, a PS steel wire, or a PS steel bar in a section where a tensile stress is applied to the concrete structure, do. Since the prestressed concrete structure can include the concrete area of the tensile section in the calculation of the moment of inertia of the section, it is possible to minimize the cross section of the member, so that it can be lengthened or the weight can be reduced compared with a general concrete structure. Prestressed concrete structures with these advantages are widely used for beam of buildings, girders of bridges, retaining walls, culvert, PHC piles, and shell-structured plate-type structures.

The prestressed concrete structure is divided into pretension type and post tension type depending on the tension time of the tension material. The pre-tension type is tensioned by applying tension to the tensions such as PS steel wire, PS steel wire or PS steel bar. It is a method of introducing the prestress into concrete by slowly pouring the tension of the tensile material after the concrete is laid and the concrete is hardened. The use of prestressed concrete members using pre-tensioning method is increasing in many countries around the world due to the simplicity of construction and the ease of quality control in the precast construction site. In particular, the use of composite beams that integrate steel beams and prestressed concrete increases .

As a background of the present invention, there is a patent registration 10-0730018 'Prestressed steel composite type and its construction method' (patent document 1). This patent relates to a prestressed steel composite type which integrates a steel beam and a prestressed concrete. By transferring precast members manufactured in appropriate lengths to the site and connecting the respective members to the site, The prestressed concrete is required to have a prestressing bed and the tension member is disposed only at the lower end of the composite beam to provide a cross sectional shape It is disadvantageous in that the prestress is uniformly introduced regardless of the moments.

Patent Registration No. 10-0730018 'Prestressed steel composite type and its construction method'

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a prestressed composite beam capable of placing a tension material corresponding to a moment generated in a member into which a prestress is introduced.

Another object of the present invention is to provide a production method capable of composing a prestressed composite bow without a prestressing bed in performing a pretension process.

A method of making a bedless prestressed composite beam according to a preferred embodiment of the present invention is characterized in that the upper flange, the lower flange spaced apart from the upper flange and having a wider width than the upper flange, A directional switch installed in a steel beam between an end fusing plate and an end fusing plate which are installed at a distance from the center of the steel beam at the joining plate, In step 1; A second step of bending by means of a direction changing mechanism and disposing and stretching a tension member so as to penetrate through the end fixing plate and the joint plate; Three steps of installing the concrete form perpendicularly to the lower flange at both ends of the lower flange of the steel beam and placing the concrete between the end fixing plates and the formwork and curing until the required strength of concrete is developed; A fourth step of releasing the tension of the tension member and cutting the tension member outside the end fusing plate to introduce the compression prestress through the tension member attached to the concrete; .

Here, the direction changing section is divided into a first direction switching port attached to the lower surface of the steel beam upper flange at the side of the steel beam beam and a second direction switching port attached to the upper surface of the steel beam lower flange at the center of the steel beam. The two-way switchgear includes a bottom plate joined to the upper and lower flanges, a side plate vertically joined to the bottom plate at a distance from each other, a connecting plate connecting the upper ends of the side plates and spaced apart from each other in the height direction And a tension member may be disposed between the bolts of the direction switching opening.

In the meantime, between the first stage and the second stage, a plate-shaped vertical stiffener connected to the upper flange at both ends of the upper flange perpendicularly to the lower flange at regular intervals in the steel beam longitudinal direction is additionally provided, The integrity of the behavior of the steel beam and the concrete can be secured and the concrete can be prevented from falling out of the steel beam.

Alternatively, between step 1 and step 2, a plate-shaped sloped stiffener connected to the upper flange of the steel beam and the web at both ends of the steel beam at regular intervals in the longitudinal direction of the steel beam is additionally provided, It is possible to secure the integrity of the behavior of the concrete with the concrete, and to prevent the concrete from falling off from the steel beam.

Alternatively, a step in which stud bolts are further provided so as to protrude from the web of the steel beam at regular intervals in the longitudinal direction of the steel beam is added between the first and second stages so that the stud bolts secure the integrity of the behavior of the steel beam and the concrete , It is possible to prevent the concrete from falling off from the steel beam.

According to the present invention, it is possible to arrange the tension member in a shape corresponding to the force exerted by the member and to introduce the corresponding prestress into the member, so that a reasonable and economical cross-section can be formed, There is an effect that it can cope efficiently.

Further, according to the present invention, it is possible to prevent the cross section from becoming excessively larger than necessary in the moment section, and it is possible to reduce the weight of the member by disposing the concrete structure at both end sections where no moment is generated.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention, Shall not be construed as limiting.
1 is a perspective view of a pre-tension composite beam produced by a manufacturing method according to the present invention.
2 is a sectional view showing a procedure of a method for manufacturing a bedless prestressed composite beam according to the present invention.
3 is a cross-sectional view showing an installation position of the prestressed composite beam according to the present invention.
4A is a cross-sectional view of a steel beam according to another embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A.
FIG. 5A is a cross-sectional view of a steel beam according to another embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along line BB of FIG. 5A.
6A is a cross-sectional view of a steel beam according to another embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along the line CC of FIG. 6A.
7 is a sectional view of a steel beam according to another embodiment of the present invention.

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

1 is a perspective view of a pre-tension composite beam produced by a manufacturing method according to the present invention.

As shown in FIG. 1, the pre-tension composite according to the present invention includes a steel beam 10 having an asymmetric H-shaped cross section, upper and lower flanges 11 and 12 and a web 13 connecting the upper and lower flanges 11 and 12, A joint plate 20 joined to both ends of the beam 10 is fixed between the end fusing plate 30 and the end fusing plate 30 provided at a distance from the center of the steel beam 10 in the joint plate 20 And a direction switching port 50 installed in the steel beam 10 between the tension member 40 and the end fusing plate 30 for introducing the prestress into the steel beam 10 and curving the tension member 40.

Hereinafter, a method of producing a bedless prestressed composite beam according to the present invention will be described in order.

2 is a sectional view showing a procedure of a method for manufacturing a bedless prestressed composite beam according to the present invention.

Step 1) Placing the steel beams (Figure 2a)

First, the steel beam 10 is placed in the prestressing work position.

1, the steel beam 10 includes an upper flange 11, a lower flange 12 spaced apart from and spaced apart from the upper flange 11 and wider than the upper flange 11, upper and lower flanges 11 and 12 Up webs 13 which are arranged perpendicularly to the webs 13 and which connect them can be made as a lengthy material having an asymmetrical H-shaped cross-sectional shape and can be manufactured by the rolling process, and the built- Built-up products. In case of manufacturing by built-up, the width and strength of the upper and lower flanges can be different without being limited by the cross-sectional size, thereby making it possible to construct a more efficient cross-section.

The reason why the lower flange 12 of the steel beam 10 is made wider than the upper flange 11 is that the lower flange 12 serves as a prestressing bed so that a pretensioning composite bearing without a prestressing bed can be manufactured. In other words, unlike the conventional method in which a prestressing bed is provided and used as a bottom plate form of a prestressed concrete member, the lower flange 12 of the steel beam 10 becomes a concrete lower form when the concrete is to be described later, It does not require a separate form and after concrete curing it is combined with concrete and behaves as a composite beam.

As shown in Figs. 1 and 2, the direction changing port 50 is formed in the first direction to be attached to the undersurface of the steel beam upper flange 11 at both ends of the steel beam 10 to form an inflection point of the tensile material 40, And a second direction switching mechanism 52 attached to the upper surface of the steel beam lower flange 12 at the center of the transition beam 51 and the steel beam 10. The first and second direction switching elements 51 and 52 are similar to each other and have a bottom plate 511 joined to the upper and lower flanges, a side plate 512 vertically joined to the bottom plate at a distance from each other, A connecting plate 513 connecting upper ends of the plate 512 and a plurality of bolts 514 coupled between the both side plates 512 at intervals along the height direction. Bolts 514 may be replaced by steel rods rotatably coupled between both side plates 512 and the number of bolts 514 is determined by the number of tension members 40. [

Step 2: Tensions  By placing Tensile  Step (Figure 2b)

Next, the tensile member 40 is disposed so as to penetrate between the bolts 514 of the direction switching member 50 and the end fusing plate 30 and the joint plate 20. The through holes 30a and 20a must be formed in advance in the end fusing plate 30 and the joint plate 20 in order to penetrate the tension member.

Although not shown, a tension member 40 is fixed to one end of the prestressed composite band, and a tension device is provided at the other end of the prestressed composite band to tension the tension member 40 by any method known in the pre- .

Step 3: Curing for a certain period of time after concrete pouring (FIG. 2C)

Next, the unillustrated form is installed perpendicularly to the lower flange 12 at both widthwise ends of the lower flange 12 of the steel beam 10, and a reinforcing bar or the like is additionally provided therebetween to form a gap between the end fixing plates 30 and the die Concrete 60 is poured and cured until the required strength of concrete is developed.

Step 4: Tensions  Cut into concrete Prestress  The step of introducing (Figure 2d)

When the concrete 60 is cured so that the required strength is developed, the tension member 40 is released and the tension member 40 is cut from the end portion of the fixing plate 30, and the tension member 40 is attached to the concrete 60 Compression prestress is introduced.

The completed prestressing composite beam is connected to the moment frame section of the structure as described above. That is, it is pin-joined so as to be simply supported between the column 1 and the girder 2 so as to be able to resist the momentum.

When installed between the columns 1, as shown in FIG. 2E, it is possible to connect the column 1 directly to the joining plate 20. When installed between the girders 2 as shown in FIG. 2F, A connecting plate 21 may be additionally provided on the outside of the plate 20 so as to be perpendicular to the joining plate so as to be connected to the girder 2.

3 is a cross-sectional view showing an installation position of the prestressed composite beam according to the present invention.

As shown in FIG. 3, the prestress synthesis according to the present invention can be efficiently applied to the moment frames of the frame structure.

For example, it may be provided in a bracket 3 that is disposed in a section between the columns 1 and provided on the column 1 in advance.

4A is a cross-sectional view of a steel beam according to another embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line A-A of FIG. 4A.

As shown in Figs. 4A and 4B, the steel beam 10 is formed in a plate-like shape perpendicular to the upper flange 11 at both ends of the upper flange 11 of the steel beam 10 at regular intervals in the longitudinal direction, The stiffener 14 may be further formed. That is, a step of installing the vertical stiffener 14 between the first step of disposing the steel beam 10 and the second step of disposing the tensile material 40 and pulling it may be additionally constituted.

FIG. 5A is a cross-sectional view of a steel beam according to still another embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along line B-B of FIG. 5A.

As shown in Figs. 5A and 5B, the steel beam 10 is provided with a plate-like inclination connected to the upper flange 11 of the steel beam 10 and the web 13 at both ends of the lower flange 12 at regular intervals in the longitudinal direction A stiffener 15 may be further formed. That is, it is possible to additionally constitute a step of installing the inclined stiffener 15 between the first step of disposing the steel beam 10 and the second step of disposing the tensile material 40 and pulling it.

FIG. 6A is a cross-sectional view of a steel beam according to another embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along line C-C of FIG. 6A.

The stud bolt 16 may be formed so as to protrude from the web 13 of the steel beam 10 at regular intervals in the longitudinal direction of the steel beam 10, as shown in Figs. 6A and 6B. That is, the step of installing the stud bolt 16 between the first step of disposing the steel beam 10 and the second step of disposing the tensile material 40 and pulling it may be additionally constituted.

The vertical and inclined stiffeners and the stud bolts 14,15 and 16 are used to ensure the integrity of the behavior of the steel beam 10 and the concrete 60 and to prevent the concrete 60 from falling off from the steel beam 10 prevent.

7 is a sectional view of a steel beam according to another embodiment of the present invention.

7, a third direction switching opening 53, which is higher than the second direction switching opening 52, is provided between the first and second direction switching openings 51, 52 and the lower flange 12 of the steel beam, And the tension member 40 may be disposed on the upper surface in a different bent form. The configuration of the redirection port 50 is not limited to the first, second, and three-way switching ports 51, 52, 53, and may be appropriately configured and arranged according to the shape of the bending moment received by the composite. Although the method of disposing the tension member in the shape of a straight line has been described above, the present invention is not limited thereto. The direction changing unit 50 may be formed of a shape of a moment, Can be appropriately configured to arrange the tension members.

As described above, according to the present invention, it is possible to arrange the tension member in a shape corresponding to the force applied to the member and to introduce the corresponding prestress into the member, thereby making it possible to construct a reasonable and economical cross section, It is possible to efficiently cope with the bending moment.

In addition, it is possible to prevent the cross section from becoming excessively larger than necessary in the section of the moment-to-moment, and it is advantageous in that the member can be lightened by eliminating the concrete structure in both end sections where no moment is generated, and the deflection can be efficiently controlled.

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

10: steel beam 11: upper flange of steel beam
12: lower flange of steel beam 13: web of steel beam
14: vertical stiffener of steel beam 15: inclined stiffener of steel beam
16: stud bolt of steel beam 20:
30: end fixing plate 40: tension member
50: direction changing section 60: concrete
1: Column 2: Girder
3: Bracket

Claims (5)

A lower flange 12 spaced apart from and spaced apart from the upper flange 11 and wider than the upper flange 11 and a web 18 vertically disposed on and connecting the upper flange 11 and the upper flange 11, 13 is an asymmetric H-shaped cross section, a joint plate 20 joined to both ends of the steel beam 10, an end portion provided at a distance from the joint plate 20 to the center of the steel beam 10, A step (1) of placing a direction changing port (50) provided in the steel beam (10) between the fixing plate (30) and the end fusing plate (30) at a working position;
A second step of folding and deflecting the tension member 40 so as to pass through the end fusing plate 30 and the joint plate 20 by the direction switching member 50;
The form is provided perpendicularly to the lower flange 12 at both ends in the width direction of the lower flange 12 of the steel beam 10 and the concrete 60 is laid between the end fusing plates 30 and the formwork, Three stages of curing until cured; And
Removing the tensioning material 40 and cutting the tensioning material 40 outside the end fusing plate 30 to introduce a compression prestress through the tensioning material 40 attached to the concrete 60; A method of making a rest composite. The method according to claim 1,
The redirecting opening (50)
A first direction switching port 51 attached to the lower surface of the steel beam upper flange 11 at both ends of the steel beam 10 and a second direction switching port 51 attached to the upper surface of the steel beam lower flange 12 at the center end side of the steel beam 10, And a direction switching opening 52,
The first and second direction switching ports 51 and 52 include a bottom plate 511 joined to the upper and lower flanges, a side plate 512 vertically joined to the bottom plate at a distance from each other, And a plurality of bolts 514 interposed between the side plates 512 and spaced apart from each other in the height direction so as to form a tension member 514 between the bolts 514 of the direction changing member 50. [ (40) is disposed on the outer periphery of the outer frame. The method according to claim 1,
Between steps 1 and 2,
A step of installing a plate-shaped vertical stiffener 14 connected at both ends of the upper flange 11 of the steel beam 10 at regular intervals in the longitudinal direction of the steel beam 10 by a lower flange perpendicularly to the upper flange 11 In addition,
The vertical stiffener (14) secures the integrity of the behavior of the steel beam (10) and the concrete (60) and prevents the concrete (60) from falling off from the steel beam (10) Production method. The method according to claim 1,
Between steps 1 and 2,
A step of installing a plate-like inclined stiffener 15 connected to the upper flange 11 of the steel beam 10 and the web 13 at both ends of the lower flange 12 at regular intervals in the longitudinal direction of the steel beam 10 In addition,
Wherein the inclined stiffener (15) secures the integrity of the behavior of the steel beam (10) and the concrete (60) and prevents the concrete (60) from falling off from the steel beam (10) Production method. The method according to claim 1,
Between steps 1 and 2,
In addition to the step of further installing the stud bolts 16 so as to protrude from the web 13 of the steel beam 10 at regular intervals in the longitudinal direction of the steel beam 10,
Wherein the stud bolt (16) secures the integrity of the behavior of the steel beam (10) and the concrete (60) and prevents the concrete (60) from falling off the steel beam (10) Production method.

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