KR102245795B1 - PSC girder with efficiently placed prestressing strand - Google Patents

Abstract

The present invention relates to a PSC girder with efficient arrangement of steel wires, which comprises: a prestressed concrete (PSC) girder held and installed at both points spaced apart from each other; and PS steel materials disposed in a longitudinal direction inside the PSC girder and fixed to both ends of the PSC girder. The PS steel material is arranged convexly to a lower side, and both ends are distributed and disposed vertically, and at the same time the centroid thereof is arranged to coincide with the centroid of the PSC girder. The present invention can reduce the generation of unnecessary tensile stress and compressive stress compared to an existing PSC girder by arranging the PS steel material in the shape of a bending moment on the PSC girder. In addition, by distributing an anchoring end on the side and upper portions of the PSC girder, the occurrence of excessive stress due to a concentrated load occurring at the anchoring end can be reduced, thereby increasing prestress efficiency as well as improving stability and workability.

Description

PSC girder with efficiently placed prestressing strand}

The present invention relates to a PSC girder, and more particularly, by arranging a PS steel material in the shape of a bending moment diagram on the PSC girder, compared to the conventional PSC girder, a steel wire capable of reducing unnecessary tensile stress and compressive stress is efficiently disposed. It is about the PSC girder.

In general, in a girder bridge, a girder is installed in a longitudinal direction (longitudinal direction) between an abutment (pier) and an abutment (pier), and a bottom plate (slab) is installed on the upper surface of the girder.

In addition, a bridge structurally separated from the pier point is called a simple bridge, and a continuous bridge is called a continuous bridge.

In addition, the girder is installed on the upper part of the abutment (pier) so that the bridge can secure the load bearing capacity, and a floor plate (slab) is installed on the upper part. There are various types of the girders, among which there is a PSC girder (Prestressed concrete girder) that introduces a tension force to increase the load-bearing capacity of a bridge or to resist sag or crack caused by overload or use.

The PSC girder can be formed by reinforcing reinforcing bars in a formwork, arranging a sheath pipe, and then pouring and curing concrete. In addition, it is manufactured to resist external force by applying a tensile force to the strand to generate a compressive force in the tensile portion of the concrete.

As a prior art of the PSC girder, Korean Patent Laid-Open Publication No. 10-2016-0050760'steel composite PSC girder' has been disclosed. This prior art relates to a girder constituting a bridge, a flange made of a plate-shaped steel material that is long in one direction, coupled in a direction substantially perpendicular to the flange, and becomes longer from one end of the flange to the central part, and then again from the central part. A plate-shaped web composed of a shorter steel material, a first box in the shape of a steel box coupled to the opposite side of the flange among the webs, a first concrete that is a concrete filled inside the box, and a prestress for applying prestress to the first concrete Includes means. In addition, the prestressing means is a configuration comprising a sheath pipe embedded in the concrete, a tension member disposed inside the sheath pipe, and a fixing means for fixing the tension member in a state in which a tensile force is applied.

The prior art has a problem in that stress is concentrated in a certain section of both ends of the PSC girder because the fixing ends (fixing means) of the stranded wire (tension material) are installed at both ends of the PSC girder to introduce prestress. In addition, there is a problem in that the height of the bridge increases due to the high PSC girder, and the construction cost increases accordingly.

Republic of Korea Patent Publication No. 10-2016-0050760

The present invention has been conceived to solve the above problems, and an object of the present invention is to arrange a PS steel material in the shape of a bending moment on a PSC girder to avoid unnecessary tensile stress on the upper end and unnecessary tensile stress on the lower end compared to the conventional PSC girder. It is to provide a PSC girder in which steel wires that can reduce the occurrence of compressive stress are efficiently arranged.

In addition, it is to provide a PSC girder in which a steel wire capable of reducing the occurrence of excessive stress occurring at the fixing end by dispersing the fixing end of the PSC girder is efficiently arranged.

In addition, by providing a cutout under the end of the PSC girder, it is to provide a PSC girder in which a steel wire capable of reducing the installation height of the PSC girder and reducing construction cost is efficiently arranged.

A PSC girder in which steel wires are efficiently arranged according to an example of the present invention includes a PSC (prestressed concrete) girder mounted and installed at both points spaced apart from each other; And a PS steel material disposed in the length direction inside the PSC girder and fixed to both ends of the PSC girder, wherein the PS steel material is disposed convexly downward, and both ends are distributed vertically or distributed horizontally. It may be arranged or distributed vertically and horizontally, and at the same time, the center may be arranged to coincide with the center of the PSC girder.

The PSC girder further includes a second PS steel material disposed in the longitudinal direction inside the PSC girder and fixed at a position spaced inward from both ends of the PSC girder, and the second PS steel material is disposed convexly downward, both ends May be disposed on an intermediate fixing portion protruding on the neutral axis while being both sides of the PSC girder.

The PSC girder further includes a third PS steel material disposed in the longitudinal direction and fixed to both ends of the PSC girder, and the third PS steel material is disposed convexly downward, and both ends of the PSC girder It may be disposed on an end fixing portion which is a side surface and protrudes on a neutral axis.

The PSC girder further includes a fourth PS steel material disposed in a longitudinal direction inside the PSC girder and fixed at a position spaced inward from both ends of the PSC girder, and the fourth PS steel material is disposed convexly downward, at both ends May be disposed in the second intermediate fixing unit recessed in the upper side of the PSC girder.

The height of the upper surface of the PSC girder may be lowered when the PSC girder includes a cutout portion removed from the cutout under the end of the PSC girder, and a bridge support is installed under the cutout portion to be installed.

It may further include a shear reinforcing plate covering a lower surface of the cutout portion of the PSC girder, a lower surface of the PSC girder adjacent thereto, and a connection surface connecting them.

The PSC girder may be characterized in that it is a square, I-shaped, box-shaped, or U-shaped.

The PSC girder may be characterized in that the segmented type divided into a plurality.

The concrete forming the PSC girder may be characterized in that it comprises fly ash or/and blast furnace slag.

Further comprising a fixing clip for maintaining a gap between the PS steels or between the PS steels and the reinforcing bars reinforced in the PSC girder or fixing the position of the PS steels, the fixing clip has an S-shaped tail on the tail It is formed continuously while biting, and the fixing clip may be partially cut or press-fit to facilitate cutting or bending.

The PSC girder is continuously installed at the pier point, and PS steels installed on the upper side of the PSC girder adjacent to the continuously installed pier point may be connected to each other.

According to the present invention, by arranging the PS steel material in the shape of a bending moment on the PSC girder, it is possible to reduce the occurrence of unnecessary tensile stress on the upper end and unnecessary compressive stress on the lower end compared to the conventional PSC girder.

In addition, by dispersing the fixing end of the PSC girder, it is possible to reduce the occurrence of excessive stress occurring at the fixing end.

In addition, by providing a cutout under the end of the PSC girder, it is possible to reduce the construction cost by lowering the installation height of the PSC girder.

1 to 10 are perspective views and cross-sectional views showing various embodiments of a PSC girder in which a steel wire is efficiently disposed according to an example of the present invention
11 is a view showing a fixing clip to which the present invention is applied
12 to 14 are views showing the installation state of the present invention
15 is a view showing a segment of the present invention

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing an embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the constituent elements of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are for distinguishing the constituent element from other constituent elements, and the nature, order, or order of the constituent element is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but another component between each component May be “connected”, “coupled” or “connected”.

Hereinafter, a PSC girder in which a steel wire according to an example of the present invention is efficiently disposed will be described with reference to the drawings.

1 to 10 are views showing various embodiments of a PSC girder in which a steel wire according to an example of the present invention is efficiently disposed.

The PSC girder 100 in which the steel wire according to an example of the present invention is efficiently disposed may include a PSC girder 110 and a PS steel material 120.

The PSC girder 110 may be mounted and installed at both points, that is, shift and shift, shift and pier, or pier and pier. The PSC girder 110 may be a square, an I-shaped, an empty box-shaped, or a U-shaped. The PSC girder 110 may be formed by placing the reinforcing bar and the PS steel 120 on the formwork, and then pouring and curing concrete.

The concrete forming the PSC girder 110 may include fly ash or/and blast furnace slag. Fly ash is coal ash produced by combustion boilers such as thermal power plants, and refers to fine granular particles contained in combustion waste gas and recovered by a dust collector. Concrete including fly ash has effects such as improving fluidity, reducing bleeding, reducing hydration calorific value, inhibiting alkali aggregate reaction, and improving concrete watertightness.

Blast furnace slag is a by-product that occurs when pig iron is made from iron ore in a blast furnace, and it can be said that rocks contained as impurities in iron ore are formed by compounding with lime. Concrete including blast furnace slag has effects such as increased chemical resistance, increased durability, and long-term strength.

The PS steel 120 may be provided with a sheath tube and disposed inside the sheath tube. The PS steel 120 may be installed after the concrete is cured and the formwork is removed. When arranged in a curved line as in this embodiment, a sheath tube is usually installed, and a PS steel material 120, which is a stranded wire, may be disposed therein.

The PS steel 120 is disposed convexly downward, and both ends are distributed vertically, distributed horizontally, or distributed vertically, horizontally, and at the same time, the center may be disposed to coincide with the center of the PSC girder 110. have. By matching the center of the PS steel 120 with the center of the PSC girder 110, unnecessary compressive stress or tensile stress at the end of the PSC girder 110 may not occur.

Referring to FIG. 6, it may further include a second PS steel 130 disposed in a longitudinal direction inside the PSC girder 110 and fixed at a position spaced from both ends of the PSC girder 110 inwardly. . The second PS steel 130 is disposed to be convex downward, and both ends thereof may be disposed on the intermediate fixing portions 131 which are both sides of the PSC girder 110 and protrude on the neutral axis. The second PS steel 130 is fixed at a position spaced from both ends of the PSC girder 110 inwardly, thereby remarkably improving the stress concentration at the ends of the PSC girder 110. In addition, the second PS steel 130 is fixed to the intermediate fixing part 131 protruding on both sides of the PSC girder 110 and protruding on the neutral axis, thereby preventing unnecessary bending compressive stress or bending tensile stress at the fixing point have.

Referring to FIG. 7, the PSC girder 110 may further include a third PS steel 140 disposed in the longitudinal direction and fixed to both ends of the PSC girder 110. The third PS steel 140 is disposed to be convex downward, and both ends may be disposed on both sides of the PSC girder 110 and on the end fixing portions 141 protruding on the neutral axis. The third PS steel 140 is fixed on both sides of the PSC girder 110 and on the end fixing portions 141 protruding on the neutral axis, thereby preventing excessive stress concentration.

Referring to FIG. 8, it may further include a fourth PS steel 150 disposed in a longitudinal direction inside the PSC girder 110 and fixed at a position spaced inward from both ends of the PSC girder 110. . The fourth PS steel 150 is disposed to be convex downward, and both ends may be disposed on one or more second intermediate fixing units 151 that are recessed in the upper surface of the PSC girder 110. When the PSC girder 110 is divided into three (see Fig. 15), the fourth PS steel 150 can be easily fixed at both ends of the central portion.

Referring to FIG. 9, it may further include a cutout 160 removed from the cutout below the end of the PSC girder 110. The cutout 160 can save construction cost by lowering the installation height of the girder. That is, by lowering the height of the upper surface of the PSC girder 110 and the height of the bridge in the state installed on the upper side of the bridge support, it is possible to reduce the amount of earthwork on the connecting road.

Referring to FIG. 10, a shear reinforcing plate 170 covering a lower surface of the cutout 160 and a lower surface of the PSC girder 110 adjacent thereto and a connection surface connecting them may be further included. When cutting the lower end of the PSC girder 110, shear resistance may be reduced. The shear reinforcing plate 170 may compensate for the reduced shear resistance.

Referring to FIG. 11, it may further include a fixing clip 180 for maintaining a gap between the PS steels or between the PS steels and the reinforcing bars reinforced in the PSC girder 110 or fixing the position of the PS steels. have. The fixing clip 180 may be continuously formed in an S-shape while biting the tail on the tail. The fixing clip 180 may be partially cut or press-fit to facilitate cutting or bending. The fixing clip 180 can easily set the position between the PS steels that continuously change their positions or between the reinforcing bars. In addition, it can be cut to a required length using a cut or press-fitted part, or bent and installed if necessary.

13, the PSC girder 110 may be connected to each other PS steel at the pier position. That is, by connecting the PS steels installed on the upper side of the adjacent PSC girders 110 to each other, it is possible to reduce the positive moment in the form of a continuous beam.

The following describes the manufacturing process of the present invention configured as described above.

First, a formwork may be formed according to the design drawing, and a reinforcing bar and a sheath tube may be arranged in the formwork. The sheath pipe may be arranged so that the PS steel 120 is fixed at both ends of the PSC girder 110, and the second PS steel 130 is fixed at a position spaced inward from both ends of the PSC girder 110 It can be arranged as much as possible. In addition, the sheath tube may be disposed so that the third PS steel 140 is fixed on the neutral axis at both ends of the PSC girder 110, and is fixed at a position spaced inward from both ends of the PSC girder 110. The fourth PS steel 150 may be arranged to be fixed. PS steel can be pre-installed inside the sheath tube or inserted after the concrete has hardened.

The sheath tube is installed between the sheath tube or between the sheath tube and the reinforcing bar using the fixing clip 180, so that the position of the sheath tube can be easily set. The fixing clip 180 is formed continuously while biting the tail on the tail in an S-shape, and connects the reinforcing bar and the sheath tube or the sheath tube and the sheath tube to maintain the required distance. Since the fixing clip 180 is partially cut or pressed, it is easy to cut or bend, so that the length can be cut to fit the distance between the sheath tube and the reinforcing bar.

In addition, the formwork may be formed such that cutouts 160 are formed in the lower portions of both sides of the PSC girder 110. A shear reinforcing plate 170 for reinforcing the strength of the PSC girder 110 may be positioned in the cutout 160. A shear material such as an anchor bolt is provided on the upper surface of the shear reinforcing plate 170 to increase the bonding force with the concrete to be poured.

After the concrete is poured and cured in the formwork in which the reinforcing bar and the sheath tube are arranged in the above process, the formwork may be dismantled to form the PSC girder 110. After prestressing the PS steel material inside the sheath tube, it can be fixed in the fixing unit to form the PSC girder 100 in which the steel wires of the present invention are efficiently disposed.

12 to 13, the PSC girder 100 in which the steel wire formed by the above process is efficiently arranged can be seated on the bridge support installed on the abutment (pier).

Since the cutout 160 is seated on a bridge support installed on an abutment or pier, the height of the upper surface of the PSC girder 110 may be lowered.

Referring to FIG. 14, the cutout 160 may be formed only on one side of the PSC girder 110.

By installing the center of the fixing part of the PS steels in the center of the cross section of the PSC girder 110, unnecessary positive moments or positive moments may not be generated. In addition, the PS steel material does not pass under the end of the PSC girder, so it can be partially cut.

If the second intermediate fixing part 151 is installed on the upper part of the PSC girder 110 to introduce prestress, it is very ideal because it can create a positive moment diagram opposite to the positive moment diagram generated by dead load and live load. .

It is possible to form a bridge while constructing a floor plate on the PSC girder 110 seated on the abutment or pier.

Referring to FIG. 15, the PSC girder 100 in which the steel wires are efficiently disposed may be formed by segmenting as necessary.

In the above, even if all the constituent elements constituting the embodiments of the present invention have been described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all of the constituent elements may be configured or operated by selectively combining one or more. In addition, terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components. It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: PSC girder in which steel wires are efficiently placed
110: PSC girder 120: PS steel
130: second PS steel 131: intermediate fixing portion
140: third PS steel 141: end fixing portion
150: fourth PS steel 151: second intermediate fixing unit
160: cutout 170: shear reinforcement plate
180: fixing clip

Claims (10)

PSC (prestressed concrete) girders mounted and installed at both points spaced apart from each other; And
Including; a PS steel material disposed in the longitudinal direction inside the PSC girder and fixed to both ends of the PSC girder,
The PS steel is disposed convexly downward, and both ends are distributed upward and downward, and the center of the PSC is arranged to coincide with the center of the PSC girder,
A second PS steel material disposed in the length direction inside the PSC girder and fixed at a position spaced inward from both ends of the PSC girder and disposed longitudinally inside the PSC girder and fixed at both ends of the PSC girder It further includes a third PS steel material,
The second PS steel material is disposed convexly downward, and both ends are disposed in an intermediate fixing unit protruding on the neutral axis while being both sides of the PSC girder,
The third PS steel material is disposed to be convex downward, and both ends are disposed on both sides of the PSC girder and at the end fixing portions protruding on the neutral axis,
Maintain a gap between the sheath pipes including the PS steel material inside, or between the sheath tube including the PS steel material inside and the reinforcing bar reinforced inside the PSC girder, or fix the position of the sheath tube including the PS steel material inside Further comprising a fixing clip, wherein the fixing clip is formed continuously while biting the tail in the S-shape, and at the same time, it is cut to a required length or partially cut or pressed to facilitate bending when necessary,
Including a cut-out portion removed by cutting off the lower end of the PSC girder,
The height of the upper surface of the PSC girder in the state where a bridge support is installed and installed under the cutout is lowered,
A PSC girder in which the steel wire is efficiently arranged, further comprising a shear reinforcing plate covering a lower surface of the cutout portion of the PSC girder and a lower surface of the PSC girder adjacent thereto and a connection surface connecting them. delete delete The method according to claim 1,
Further comprising a fourth PS steel material disposed in the longitudinal direction inside the PSC girder and fixed at a position spaced inward from both ends of the PSC girder,
The fourth PS steel material is disposed to be convex downward, and both ends of the PSC girder are disposed in a second intermediate fixing unit recessed in the upper side of the PSC girder. delete delete The method according to claim 1 or 4,
The PSC girder is a square, I-shaped, box-shaped, or U-shaped, characterized in that the steel wire is efficiently arranged PSC girder. The method according to claim 1 or 4,
The PSC girder is a PSC girder efficiently arranged steel wire, characterized in that the segmented type divided into a plurality. The method according to claim 1 or 4,
The concrete forming the PSC girder is a PSC girder in which steel wires are efficiently arranged, characterized in that it comprises fly ash or/and blast furnace slag. The method according to claim 1 or 4,
The PSC girder is continuously installed at a pier point, and PSC girders in which steel wires are efficiently arranged, characterized in that the PS steels installed on the upper side of the PSC girder adjacent to the continuously installed piers are connected to each other.

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