KR101849254B1 - Method of constructing bridge girder with improved anti-erosion and bridge girder using the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a bridge girder, and a grouting apparatus used thereby. The method of manufacturing a bridge girder comprises: a girder preparation step of preparing a girder with a sheath pipe installed thereon; a steel strand insertion step of inserting a plurality of sheathed steel strands where steel strands are formed to be moved in an axial direction in sheaths into the sheath pipe; a grouting step of injecting a grout material into the sheath pipe and curing the grout material to integrate the sheaths of the sheathed steel strands into the grout material; and a prestress introduction step of tensioning and fixing the steel strands of the sheathed steel strands to introduce prestress to the girder after the grouting step. The sheathed steel strands are used to prevent damage to the sheaths to improve corrosion resistance. Re-tensioning and steel strand replacement are possible. The steel strands in the sheath pipe are evenly dispersed or are definitely positioned on a lower side to introduce high compressive prestress.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a bridge girder having improved corrosion resistance and introduction characteristics of a prestress, and a girder for the bridge,

The present invention relates to a method for manufacturing a bridge girder and a bridge girder manufactured thereby. More specifically, it is possible to prevent the damage of the cover by using a coated strand, In which the arrangement of the strands in the bridge is uniformly dispersed or reliably positioned at the lower side to introduce a higher compression prestress and a girder for the bridge fabricated thereby.

Generally, bridges are constructed by installing a bridge girder on a bridge structure such as a bridge pier or an alternate bridge, and a pedestrian or a bottom plate through which a vehicle passes, on the bridge girder.

Here, the bridge girder supports a fixed load of a bottom plate or a bridge girder and a live load according to the passage of a pedestrian or a vehicle. Therefore, in order to manufacture a girder having a lower load capacity and a lower cost, a prestress which cancels the load acting on the girder during the joint use is introduced in advance in the manufacturing stage. Thus, And can be applied to span bridges.

As a method of introducing a prestress into a girder for a bridge, various methods such as a method using a prestressing load have been proposed. However, as disclosed in Korean Patent Laid-Open Publication No. 10-2015-0072612 and Korean Patent Registration No. 10-1615316, A method of introducing a prestress by installing a tension member in a casing concrete of a concrete girder or a steel composite girder and fixing the tension member in a tense state is widely used.

The method of introducing a prestress using a tension material is divided into a pretension method and a post tension method. The pre-tension method is a method in which a concrete is cured in a state in which a tensile force is introduced into a strand of strand, and a prestress is introduced into a concrete portion by friction with a strand of strand. Therefore, only a plant capable of being maintained for a long time with a tension applied to strand Therefore, it is difficult to apply to a long span girder and its applicability is low.

Due to this, it is widely used to introduce a prestress into the concrete portion 91 of the girder 9 by the post tensioning method shown in Fig. The post tension system is mainly used when the concrete section 91 of the girder 9 is made in advance and the sheath tube 92a is cured so that the concrete section 91 is cured to exhibit sufficient strength. By using a wedge member 83 to the anchor head 82 in a state of introducing a tensile force P for pulling the strand 92 inserted into the anchor head 82 at both ends with a tensile jack or the like.

When a compression prestress is introduced into the lower portion of the center of the girder 9, a force acting on the bridge girder 9 such as a bottom plate (not shown) and a live load acts on the bridge girder 9 as a compensating force F ), It is possible to realize a higher load carrying capacity.

However, conventionally, in order to introduce the prestress into the concrete portion 91 by the post-tensioning method, only a nude tendon 92 having no covering in the sheath pipe 92a can be applied, The corrosion problem of the strand 92 was inevitable in the process of being completed and shared for a long time. In order to solve such a corrosion problem, the grout material is poured into the sheath pipe 92a. However, when the grout material is a solid material, there is a limit in that the strand 92 can not be re-tensioned .

On the other hand, there is a grout material held in a liquid state, but the grout material kept in a liquid state is not held around the strand 92, There is a serious problem that the strand 92 is corroded frequently. Therefore, in the case of applying a grout material in a liquid state, there arises a problem that the burden of maintenance, which is required to be filled with grout material in the sheath tube 92a at any time, becomes large.

In order to solve such a problem, a method of introducing the prestress into the unbonded steel wire with the coating formed can be sought. However, the post-tensioning method using the conventional unattached steel wire has an advantage that corrosion of the steel wire can be surely prevented, but it is dispersed and arranged in the concrete part 91 of the girder so as to pull the unattached steel wire one by one, Therefore, it takes a very long time to introduce the prestress, and the unbonded steel wire has a state in which the steel wire is inserted, which makes it difficult to introduce a large tension force.

In order to solve this problem, it is possible to find a way to install the unbonded steel wire in a bundle form on the sheath tube. However, when bundling the unbonded steel wire in the sheath tube, The coating for wrapping the steel wire is damaged by being caught by the through hole of the anchor head during the introduction of the tension force, so that there is a problem that the effect of preventing the corrosion due to the coating of the steel wire is not obtained.

On the other hand, the process of introducing the tension force to the strand 92 by the conventional post tension method is performed before the sheath tube 92a is filled with the grout material, so that the tension strand 92 inserted in the sheath tube 92a is subjected to tensile force P is introduced, the strand 92 is placed on the upper portion of the sheath tube 92a, as shown in Fig. 14B.

Particularly, in order to insert the strand 92 into the sheath tube having a length of several tens of meters, the cross-sectional area of the sheath tube 92a is formed to be at least 2.5 times the sectional area occupied by the plurality of strands 92. In the conventional post- The tension force P is introduced into the strand 92 in a state in which the sheath tube 92a disposed in the parabolic shape is positioned closer to the neutral axis of the girder than the neutral axis of the girder, The phenomenon that the strand 92 goes up is remarkable.

In the conventional post tensioning system, the strand 92 is disposed at the center of the sheath tube 92a. However, in the process of introducing the tension force P into the strand 92, As the curvature of the parabolic curve formed by the bent strand 92 becomes more gentle, there is a limit that the magnitude of the compensating force F for canceling the load when the same tensile force P is applied to the strand is small.

Under the background described above, the stranded wire inserted into the sheath tube and introducing the prestress can be accurately introduced into the sheath tube without being shifted upward, and the prestress of a predetermined size can be introduced accurately. The sheath tube is installed in a bundle shape, There is a need for a method of introducing a prestress using a stranded wire in a state in which a corrosion problem can be reliably prevented, re-tensioning is possible, and a stranded wire can be replaced.

[Patent Literature]

Korean Patent Publication No. 10-2015-0072612 (June 30, 2015)

Korean Registered Patent No. 10-1615316 (May 30, 2006)

In order to solve the above-mentioned problems, the present invention is characterized in that a plurality of stranded stranded stranded wires in a sheath tube of a girder for a bridge are arranged as sheathed strands to introduce a prestress to fundamentally solve the corrosion problem of the stranded strand, And to provide a girder for a bridge manufactured by the method.

Further, in the present invention, a plurality of coated strands are arranged in a bundle form in a sheath tube and damage to the coating surrounding the strands is prevented in the process of introducing a tension force pulling the strands, thereby completely solving the corrosion problem of the strands in common The purpose.

It is another object of the present invention to induce a strand in a sheath tube to be directed to the lower side in the direction of gravity instead of upwardly displacing the upper side so that a higher load can be canceled even if the same tensile force is introduced into the strand.

Further, according to the present invention, it is possible to reinforce the strand of a girder into which a prestress is introduced, and to replace the strand when necessary, and to replace the strand with a higher tensile strength after construction to improve the load- .

In order to achieve the above-mentioned object, the present invention provides a girder forming method comprising the steps of: preparing a girder provided with a sheath tube; Inserting a plurality of coated strands formed in the sheath in such a manner that the strands are movable in the axial direction; A grouting step of injecting and curing a grout material into the sheath tube so that the sheath of the coated strand is integrated with the grout material; A prestress introduction step of tensioning and fixing a strand of the coated strand after the grouting step to introduce a prestress into the girder; The present invention also provides a method of manufacturing a bridge girder.

In particular, before the grouting step, a supporting block having a first through hole passing through the coated strand at the end of the sheath tube is installed; And an anchor head installation step of separating the support block and providing an anchor head having a second through hole passing through the coated strand after the grouting step; So that the sealing performance is ensured by the support block during the grouting process and the tension force is applied to the anchor head during the introduction process of the prestress.

The coated strand is a strand in which a plurality of wires are twisted in the inside of the sheath, and a corrosion-resistant rustproofing agent such as grease, wax, or epoxy is filled between the cloth and the strand, As shown in Fig.

Thus, after the grouting step, the support block is separated and the sheath of the coated strand is removed at the end portion to expose the stranded wire. Then, the stranded wire is passed through the second through hole of the anchor head The anchor head is installed so as to penetrate the sheet, and the sheet is pulled and then fixed. The prestress introduction step may be performed after the grouting for a predetermined period after the grouting step.

The sheath pipe installed in the girder may be a plurality of sheath pipes installed in the girder and the sheath pipe into which the coated strand is inserted may be all of the plurality of sheath pipes installed in the girder, The other part of the pipe may be blended so as to have a stranded wire without a covering.

The present invention also provides a girder for a bridge manufactured as described above.

The present invention is a method of maintaining a girder for a bridge in which a plurality of coated strands are disposed in a sheath tube of a girder and a space between the sheath tube and the coated strand is integrated by a grout material, A releasing step of releasing a fixing state of the first coated strand which is a part or more of a plurality of the coated strands; A strand removing step of extracting and removing the first strand of the first coated strand which has been released from the fixing state to the outside; A strand laying step of inserting a new second strand into the first sheath surrounding the first strand removed in the strand removing step; Introducing a prestress into the second strand by introducing a tension force to fix the strand; The present invention also provides a method of maintaining a bridge girder.

Further, the present invention is a connector for a stranded wire used in a method for maintenance of a girder for a bridge, comprising: a central body having a cross-sectional size inserted into the first covering; A first wedge fitted to one end of the center wire of the first strand; A second wedge fitted to one end of the center wire of the second strand; A first casing having one end of the first wedge and the first strand, a first casing coupled to one end of the center body and having a cross-sectional size to be inserted into the first cover; A second casing having one end of the second wedge and the second strand, a second casing coupled to the other end of the center body and having a cross-sectional size to be inserted into the first cover; The connector of a stranded wire is provided.

The trumpet member includes a through hole for passing a plurality of coated strands through a center portion of the sheath tube. A support block provided in close contact with the trumpet member and having a plurality of first through holes for passing the coated strands one by one and blocking the end of the sheath pipe from the outside; A grout material supply pipe formed in one of the trumpet member and the support block to supply the grout material into the sheath pipe; The grouting apparatus according to claim 1,

INDUSTRIAL APPLICABILITY As described above, according to the present invention, grouting material is injected into a sheath tube and cured before introducing a tensile force into the strand, after a plurality of sheathed strands are embedded in a sheath tube, Even if the strands are pulled and held at both ends of the girders in a state in which they are integrated with the tube, the strands can slide in the axial direction with respect to the sheath while introducing a tensional force to the strands to introduce a prestress.

Accordingly, the present invention is characterized in that all of the strand wire inserted into the sheath tube is covered with a covering, and the sheath is peeled off at least a part of the strand wire exposed outside the sheath tube, so that the tension jacket And the prestress can be introduced into the girder for the bridge in a state in which re-tensioning is possible in a later stage since the strand is slidable in the sheath.

In addition, since the present invention is installed in a state in which a tensile force is introduced into a strand in a coating filled with a corrosion-resistant rust preventive agent, the rustproofing agent filled in the narrow space between the sheath and the strand can be leaked to the outside It is possible to fundamentally solve the problem of deterioration in load carrying capacity due to the corrosion of the stranded wire even in the long-term common period, and it is possible to re-strain the already installed strand to the stranded wire.

Therefore, in the present invention, a part of the coated strand laid on the sheath tube of the girder is not introduced with a tension force in the production step, or only a part of the allowable load is applied, and further tension is introduced and fixed And introducing an additional prestress.

In addition, since the grouting process is not required after the process of filling the grout material in the sheath pipe before introducing the tensile force into the strand and introducing the tensile force into the strand, It is possible to shorten the construction period of the bridge because it is possible to construct the bridge by raising it immediately after the introduction of the prestress without requiring a period of waiting at the site during the grouting period.

In addition, since the grout material can be filled almost simultaneously with the concrete curing of the girder, the steam curing device for curing the grout material in winter can be performed simultaneously with the concrete curing process of the girder, Since the grouting material is always filled in the inside of the sheath tube, it is possible to fundamentally prevent the snow or rain from flowing into the sheath tube during the nighttime period, thereby completely solving the corrosion problem of the stranded wire before the bridge is raised. There is an advantage.

Further, since the present invention is in a state in which the strands in the cover can freely slide and move in the state where the cover is fixed to the grouting material in the sheath pipe, the strand in the covering can be replaced with a new strand, By replacing with a strand having high tensile strength, it is possible to obtain an advantageous effect that the load-carrying capacity of the bridge can be increased in accordance with the tendency of the steel after development.

The present invention is characterized in that the stranded wire is moved upward to the upper side of the sheath tube during the prestress introduction process because the sheathing of the strand is integrated with the sheath tube by the prestress introduction process in which the strand is introduced and fixed by introducing a tensional force. So that it is possible to obtain the effect of introducing the prestress which cancels the higher load even with the same tension force.

Further, in the present invention, a guide pipe for guiding a coated strand is extended to a support block for sealing the end portion of the sheath pipe during the grouting process, so that the sagging due to the self weight of the coated strand during the grouting process is suppressed And the cover surrounding the strand is integrally formed with the grout material in a state of being straightly extended from the end of the girder so that the unnecessary frictional resistance can be minimized when introducing the tension to the strand in the prestress introduction process and the replacement process of the strand can be facilitated Can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a construction for introducing a prestress into a girder for a bridge using a stranded wire,
2 is an enlarged cross-sectional view of a portion 'A' of FIG. 1,
3 is a flowchart sequentially illustrating a method of manufacturing a girder for a bridge according to an embodiment of the present invention,
4 is a sectional view showing a configuration of a grouting apparatus used in the manufacturing method of Fig. 3,
Figs. 5A to 13 relate to a step-by-step configuration of a method for manufacturing a bridge girder according to Fig. 3,
5A to 5C are views of a girder for a bridge showing a construction in which a concrete section is provided with a sheath tube installed;
FIG. 6 is a view showing a configuration in which a coated strand is inserted into the sheath tube of FIG. 5A,
FIG. 7 is an enlarged view of a portion 'B' in FIG. 6,
8 is a view showing a configuration in which a support block is provided at an end of a girder,
9 is a view showing a configuration in which a guide tube and a push block are installed,
10A and 10B are views for explaining an action of sealing the first through hole of the support block with the elastic ring in accordance with the movement of the guide tube,
11 is a view showing a configuration for injecting a grout material in a sheath pipe,
12 is a view showing a configuration in which an anchor head is provided instead of a support block by removing the grouting device,
13 is a view showing a configuration in which a strand of a coated strand is held by a hydraulic jack and a prestress is introduced by being fixed in a state in which a tensile force is introduced,
Fig. 14A is a sectional view of the sheath tube located at the lower edge of the center of the girder along the cutting line XX in Fig. 6 with the prestress introduced by the prestressing process of Fig. 13,
Fig. 14B is a cross-sectional view of the sheath tube located at the lower edge of the center of the girder corresponding to the cutting line XX in Fig. 6 with the prestress introduced by the prestressing process of Fig.
15 is a cross-sectional view of the coated strand along the cutting line YY in Fig. 7,
FIG. 16 is a flowchart sequentially illustrating a configuration according to an embodiment of a method for maintenance of a girder for a bridge according to an embodiment of the present invention for replacing some strands of a bridge girder manufactured by the manufacturing method according to FIG.
17 is a diagram showing the configuration of S220 of FIG. 16,
Figs. 18A and 18B show detailed configurations applicable to the connector of Fig. 16,
19 is a diagram showing the configuration of S230 in Fig.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention.

4, a grouting apparatus 100 used in a method for manufacturing a bridge girder S100 according to an embodiment of the present invention is configured such that a part or more of the grouting apparatus 100 is inserted into an end portion of the sheath tube 12 A support block 120 formed with a plurality of first through holes 120a through which the coated strands 70 are passed one by one to be closely attached to the trumpet member 110, A guide pipe 130 for guiding a covered strand 70 in a linear direction for each first through hole 120a of the guide pipe 130 and a plurality of guide pipes 130, A push block 140 for moving the guide block 130 toward or away from the support block 120 and the guide block 130 disposed in contact with the step portion 120b of the first through hole 120a of the support block 120, And an elastic ring (160) which is in close contact with the coated strand (70).

As shown in FIG. 7, the trumpet member 110 is installed in such a manner that a part of the trumpet member 110 is inserted into an end portion of a sheath pipe 12 installed in a girder to which a prestress is to be introduced, and a plurality of covered strands 70 Through holes 110a are formed. That is, the through holes 110a are formed in a smaller number than the number of the coated strands 70, and as shown in the drawing, a plurality of the coated strands 70, which are formed integrally and are embedded in the sheath tube 12, Can be accommodated.

The trumpet member 110 accommodates the end portion of the sheath pipe 12 in the through hole 110a so that the concrete is inserted into the sheath pipe 12 during the process of placing the unhardened concrete in the mold Thereby preventing the liquid from flowing into the inside. The trumpet member 110 is not installed and only the sheath pipe 12 is installed during the concrete pouring process and the finishing plate corresponding to the trumpet member 110 is shaved after the curing of the concrete portion 10, Or may be hermetically coupled to the end of the pipe 12.

The grout material supply pipe 110x for supplying the grout material 60 is formed in the trumpet member 110 so that the grout material 60 is inserted into the sheath pipe after the covered strand 70 is inserted into the sheath pipe. Can be filled in the sheath tube (12). Although not shown in the drawings, the grout re-supply pipe 110x may be formed in the support block 120 in addition to the trumpet member 110. [

The support block 120 includes a plurality of first through holes 120a which are disposed in close contact with the trumpet member 110 and through which the coated strands 70 are passed one by one, Thereby guiding the respective positions at the ends of the guide grooves 70. Therefore, it is preferable that the number of the first through holes 120a is determined to be the same as the number of the coated strands 70 to be inserted into the sheath tube 12.

The support block 120 is fixed in the form of a fastening by the trumpet member 110, the fixing bolt 118 and the fixing nut 118x. The fastening position of the support block 120 and the trumpet member 110 can be set to about three to four at intervals of 90 to 120 degrees along the circumferential direction. A circular sealing ring 117 is disposed on a surface of the support block 120 and the trumpet member 110 which are in contact with each other so that the space between the support block 120 and the trumpet member 110 And the outside air are prevented from communicating with each other. At the same time, the elastic sheet 122 is interposed between the fixing nut 118x and the support block 120 so that when the fixing bolt 118 and the fixing nut 118x are engaged, the elastic restoring force of the elastic sheet 122 The support block 120 always applies a force to press the trumpet member 110 so that the tight contact state between the trumpet member 110 and the support block 120 can be maintained.

The first through hole 120a of the support block 120 is formed with a step 120b for installing the elastic ring 160 and the guide pipe 130. [ An elastic ring 160 made of rubber or the like capable of being elastically deformed is disposed at a position in contact with the step 120b and the guide pipe 130 is elongated in the direction of the outer side of the support block 120 do. Here, it is preferable that the guide pipe 130 is formed to extend in a straight line shape as shown in the drawing, and it is preferable that the guide pipe 130 extends parallel to the longitudinal direction of the girder, but it is extended to a posture with a low inclination of 15 degrees or less It is possible.

Here, the guide tube 130 is formed of a metal material having a high bending stiffness such as steel or stainless steel, so as to suppress sagging of the coated strand 70 and to maintain it in a predetermined attitude, and a compressive force is applied to the elastic ring 160 (E) in the radial direction. For this, the material and the thickness of the cross section of the guide pipe 130 are determined so that the flexural rigidity of the guide pipe 130 is higher than the flexural rigidity of the coated strand 70.

When the cover strands 70 in the sheath tube 12 are inserted one by one into the first through holes 120a of the support block 120, the cover strands 70 are linearly formed by the guide tube 130 The covered strand 70 is not sagged downward due to its own weight inside the support block 120 (inside the sheath tube), so that the unfolded posture can be maintained without being bent. Therefore, when applying the tensile force P by pulling the strand 71 of the coated strand 70 after the grouting, the friction caused by the strand 71 bent at the end of the girder can be minimized, The process of inserting a new strand 702 into the sheath 72 becomes easier even when the strand 71 is replaced as shown in Fig. In addition, it is possible to more easily align the bundle position of the coated strand after the grouting process and the position of the second through hole 210a of the anchor head used in tension.

 The guide tube 130 is slightly held in the first through hole 120a but the guide tube 130 can be moved 130d in the axial direction within the first through hole 120a when a force is applied. Guide bars 125 extending from the support block 120 in parallel with the axial direction which is the extending direction of the guide tube 130 are formed in two or more than two guide bars 125 so that the guide tube 130 can be constantly moved in the axial direction And a push block 140 which is movable along the guide bar 125 in the axial direction and fixes the plurality of guide pipes 130 is installed. That is, the push block 140 and the guide tube 130 are integrally moved so that the guide tube 130 is inserted into the first through hole 120a of the support block 120, The installation of the guide pipe 130 and the push block 140 is completed by the ball 130d fitted into the guide bar 125. [

10A, when the push block 140 moves in the direction 130d1 away from the girder 1, the end of the guide tube 130 does not press the elastic ring 160, The coated strand 70 can pass through the respective first through holes 120a of the support block 120 without being in a state of being in close contact with the coated strand 70. [

10b, the push block 140 is pushed toward the girder 1 by a guide bar (not shown). The push bar 140 is inserted into the sheath pipe 12 through the first through hole 120a, The guide pipe 130 made of a metal having higher hardness and rigidity than the elastic ring 160 presses the elastic ring 160 at the same time by moving the elastic ring 160 in the axial direction along the axial direction The elastic ring 160 expands in the radial direction while the inner circumferential surface of the elastic ring 160 is in close contact with the outer circumferential surface of the covering 72 of the coated strand 70, And the cover strand 70 are tightly filled with elastic deformation of the elastic ring 160 to block the inner space of the sheath tube 120 from the outside. The push block 140 is pressed against the guide bar 125 in a state in which the guide tube 130 is pressed so that the push block 140 can press the guide tube 130 to maintain the expanded state e of the elastic ring 160. [ And is fixed by a fixing bolt 125x.

Accordingly, since the inner space of the sheath tube 12 is maintained in a state of being completely shut off from the outside, the grout material 60 can be injected into the inner space of the sheath pipe 12 through the grout reinjecting pipe 110x It is possible to create an environment where

Hereinafter, a method of manufacturing the bridge girder 1 using the grouting apparatus 100 constructed as above will be described in detail with reference to FIG.

Step 1 : First, girders 1, 2 and 3 provided with sheath pipes 12 are prepared to prepare girders 1, 2 and 3 (S110).

As shown in FIG. 5A, in the case of the concrete girder 1, the sheath pipe 12 is installed in a form embedded in the concrete portion 10, and in the case of the steel composite girder 2 as shown in FIG. 5B The sheath pipe 12 is embedded in the concrete portion 10 synthesized with the steel girder 20. [ (Or a U-shaped opening box shape) concrete girder 3 as shown in FIG. 5C. When the box-shaped concrete girder 3 forms a continuous bridge, it acts on the central part of the span A sheath pipe 12L for installing a strand for canceling the moment to be canceled by the vertical point is installed below the neutral axis and a sheath pipe 12U for installing a strand for canceling the vertical force acting on the continuous point is provided above the neutral axis do.

Generally, the sheath pipe 12 is installed in a form buried in the concrete part 10, but the present invention is not limited to a configuration in which the sheath pipe 12 is buried only in the concrete part. The sheath pipe 12 may be made of plastic such as high density polyethylene (HDPE) , And resin. As shown in the figure, the sheath pipe 12 may be embedded in concrete, or may be formed in a shape exposed to the outside of the concrete (that is, Or in the case of a box girder, located inside the box). Also, the sheath tube 12 may be applied to an outer steel wire reinforcing application where the end portion is formed so that the introduction of the prestress can be introduced and the sheath pipe 12 is exposed to the outside.

Hereinafter, the concrete girder 1 will be described for the sake of convenience.

Step 2 : Then, as shown in Figs. 6 and 7, the coated strand 70 is inserted into the sheath tube 12 in the form of a bundle (S120). The length of the girders 1 and 2 is set to a length ranging from a short length of about 10 m to a length of 80 m so that in order to insert a plurality of coated strands 70 into the sheath tube 12, Is formed to be much larger than that of the coated strand (70). Sectional area of the sheath tube 12 is determined to be approximately 2.5 to 3 times as large as the sum of the cross-sectional areas of the coated strands 70, although there is a difference depending on the length of the girder.

Accordingly, when the coated strand 70 is inserted into the sheath tube 12, the covered strand 70 is positioned below the sheath tube 12 by gravity as shown in Fig. 14A.

7, the trumpet member 110 for introducing the tensional force to the strand 71 inserted in the sheath pipe 12 is formed integrally with the concrete portion 10 in advance in Step 1 .

15, a stranded stranded wire 71 in which a plurality of wires are twisted is disposed inside the sheath 72, and the sheath 72 and the stranded wire 72 are connected to each other. A stranded stranded wire 71 is formed so as to be movable in the axial direction with respect to the sheath 72. The sheath 72 is made of a metal such as stainless steel, The strand 71 can be moved in the axial direction with respect to the sheath 72 by pulling the strand 71 in the axial direction after the sheath 72 is integrated with the grout material 60. [

On the other hand, the present invention includes a configuration in which all the coated strands 70 are applied to a plurality of sheath pipes 12 provided on the girders 1, 2, 3 of the bridges of Figs. 5A to 5C.

Further, according to another embodiment of the present invention, the coated strand 70 can be configured to be applied to only a part of the sheath pipe of the plurality of sheath pipes 12 of the girders 1, 2, 3. In this case, a stranded wire (71, bare tendon) having no coating is provided on a sheath tube to which the coated strand 70 is not provided, and after the strand 71 is strained according to the conventional prestressing method, , And then a grouting process can be performed. Such a configuration can be utilized to introduce additional prestress after bridge construction to subsequently compensate for the difference due to the live load change of the bridge, It is possible to arrange the coated strand 70 such that it is 20 to 30% of the total strand.

Step 3 : The grouting apparatus 100 of FIG. 4 is installed at the end of the sheath tube 12 to block the inner space of the sheath tube 12 from the outside and the outer shape by the support block 120 (S 130) .

8, the support block 120 having the elastic ring 160 installed on the step 120b of the first through hole 120a is closely attached to the trumpet member 110 (120d) The member 110 and the seal ring 117 are fixed to each other with the fixing bolt 118 interposed therebetween to seal the end portion of the sheath tube 12. [

Step 4 : Next, the gap between the first through hole 120a of the support block 110 and the coated strand 70 is closed (S140).

9, the push block 140 is prepared by arranging the guide tube 130 in an array of the first through holes 120a of the support block 120, and the push block 140, The guide tube 130 and the push block 140 are inserted into the first through hole 120a of the support block 120 with the guide tube 130 passing through the guide bar 125 of the support block 120, .

As described above, the guide block 130 for guiding the coated strand 70 with a metal material having a high flexural rigidity is extended to the support block 120 for sealing the end portion of the sheath pipe 12, so that during the grouting process, The sheath 72 covering the strand 71 is integrally formed with the grout 60 in a state in which the sheath 72 is evenly extended from the end of the girder. 71, it is possible to minimize the unnecessary frictional resistance, and it is possible to obtain the advantage that the replacement step is facilitated even if the stranded wire 71 is replaced as necessary.

10B, by moving the push block 140 along the guide bar 125 toward the girder 1, a plurality of guide pipes 130, which are integrally fixed to the push block 140, The elastic ring 160 disposed at the step 120b of the first through hole 120a is pressed while simultaneously moving toward the girder 1 (130d2). The elastic ring 160 is brought into close contact with the outer peripheral surface of the coated strand 70 while expanding (e) in the radial direction to fill the gap between the first through hole 120a and the coated strand 70. [ At this time, the clearance between the trumpet member 110 and the support block 120 is blocked by the seal ring 117 between the trumpet member 110 and the support block 120.

A connection pipe 112 for facilitating the injection of the grout material 60 may be connected to the grout material supply pipe 110x formed in the trumpet member 110 as needed.

Step 5: Then, the grout material 60 injected 66 and curing in the inner space of the sheath tube 120 through the grout material supply line (110x) (S150). The grout material 60 fills the inner space of the sheath pipe 12 through the grout material supply pipe 110x and the elastic ring 160 and the seal ring 160 are fixed to the outside of the support block 120 of the grouting device 100, And is not leaked.

Here, the grout material 60 is a liquid material at the time of injection, but is selected as a material that solidifies when cured. Thus, when the grout material 60 filled in the sheath tube 12 is sufficiently cured, the sheath tube 12 and the sheath 72 of the coated stranded wire 70 are integrated by the grout material 60 .

14A, since the grout material 60 fills the inner space of the sheath tube 12 in a state in which no tension is applied to the strand 71 inside the sheath tube 12, Since the grooves 70 are located in the lower space of the sheath tube 12, the distance y1 from the neutral axis of the girder 1 to the covered strand 70 is reduced by the conventional structure The distance y2 from the neutral axis to the stranded wire 71 can be further distanced from the neutral axis.

Since the position of each coated strand is determined by the grouting material 60 before introducing a tensile force into the strand of strand, when the prestressing process is performed in the past, in the step of tensioning the strand by applying a tensile force, The problem of twisting the steel wire can be solved.

The grout material 60 can not completely fill the interior of the sheath pipe 12 and the upper portion of the interior space of the sheath pipe 12 12z may be formed. In this case, when the grout material 60 is injected into the sheath tube 12 with the tensile force introduced into the strand 71, as shown in Fig. 14B, There is a problem in that corrosion or corrosion can not be avoided by being exposed or exposed to the surface 12z. Particularly, since the stranded wire 71 is installed in a state in which a tensile force acts, it is very susceptible to corrosion. If the part 71z of the stranded wire 71 is not covered with the grout material 60, have.

On the contrary, in the present invention, when the grout material 60 is injected into the sheath tube 12, the tensile force is not applied to the coated strand 70, so that the strand 70 is disposed on the lower side of the sheath tube 12 Therefore, even if the grout material 60 can not completely fill the interior of the sheath pipe 12 and the empty space 12z is formed in the sheath pipe 12, the coated stranded wire 70 is always held by the grout material 60 The insulated performance of the coated strand 70 and the positional fixation of the coated strand 70 by the grout material 60 can be reliably ensured.

In addition, since the grouting process can be performed immediately after inserting the coated strand 70 into the sheath tube 12 of the girder, compared with the case where the grouting process is performed only after the prestressing process has been carried out through the conventional deposition period, Not only the continuity is ensured but also the grouting material 60 can be cured immediately by using the steam curing equipment carried in order to cure the concrete even in the winter season so that it is possible to reduce the management and manufacturing cost of the equipment . After the deposition of the grouting material 60 filling the sheath tube, a prestress introduction step is performed after a lapse of a deposition period (or a darkness period) described later. In step 5, the grout material filled in the sheath tube 12 Even if a cavity is generated near the fixing end, the grouting process is not the last process, so that the grouting material can be supplemented easily at any time after step 5.

On the other hand, in the case where the girder 3 forms a continuous bridge and the strand 70 is provided on the neutral axis at the continuous fulcrum as shown in Fig. 5C, steps 2 to 5 may be performed on the ground, It is also possible to install a stranded wire 70 in the sheath pipe 12U and grouting the girder 3 in a substructure such as a bridge pier.

Step 6 : Then, the grouting device 100 is disassembled and may be scratched for a certain period of time. This is because the bridge girders 1 and 2 are often not used immediately after the bridge is constructed. Therefore, after an interval of a certain period of time, the anchor head 210 necessary for tensioning and fixing the strand is installed at the position of the support block 120 (S160).

Concretely, the connecting pipe 112 connected to the grout re-supply pipe 110x is disconnected from the trumpet member 110 and the opening of the grout re-supply pipe 110x is closed with the cover 119 before the girders are stacked. After releasing the fixing nut 125x of the guide bar 125, the guide tube 130 and the push block 140 are removed, and finally the support block 120 is separated from the trumpet member 110. At this time, since the trumpet member 110 is required for tensioning and fixing of the strand, it is held in a state integrated with the concrete portion 10.

Then, the cover 72 is removed from the covered strand 70 in the region for fixing with the wedge member 230, and the strand is exposed.

12, the anchor head 210 having the second through holes 210a aligned with the first through holes 120a of the support block 120 is prepared, The anchor head 210 is positioned at the position where the support block 120 is positioned so that the removed strand 71 passes through the second through hole 210a and the anchor head 210 is placed on the trumpet member 110 . Then, the wedge member 230 is positioned (210d) on each strand 71 where the cover 72 is peeled off. Since the second through hole 210a of the anchor head 210 penetrates through the stranded wire 71 from which the sheath 72 is removed, the cross-sectional size of the second through hole 210a is smaller than the sheath- Since the stranded wire 71 which is not inserted and has no sheath is determined to have a size enough to be inserted with a tolerance, the first through hole 120a of the supporting block 120 into which the coated strand 70 is inserted .

On the other hand, even in the case of long-term field, the present invention is configured such that after the grouting material 60 fills the interior of the sheath tube 12 before the strand is tension-fixed, the laying period elapses, Rainwater inflows into the inside of the pipe 12 or rainwater flowing in the winter season does not occur. Therefore, it is possible to solve all the conventional problems in which grouting is caused by rainwater or ice.

Step 7 : The tension jack 240 is then installed to be supported on the anchor head 210 and the tension line P of the covered strand 70 is gripped by the tension jack 240, The wedge member 230 is inserted into the wedge portion 210b of the second through hole 210a to fix the stranded wire 71 at step S170.

As a result, a compression prestress is introduced into the concrete portion 10 while the tension force P is introduced into the strand 71 of the coated strand 70.

5C, the girder 3 forms a continuous bridge. The strand 70, which is provided on the sheath tube 12U on the upper side of the neutral axis at the continuous point portion, is exposed at the upper portion of the girder, Step 7 is carried out after the girder 3 is mounted on the lower structure such as the above.

Accordingly, in the conventional art, the prestress is introduced into the strand 71 that can freely flow in the sheath tube 12, so that the strand 71 is formed in the sheath tube 12 of the finally fabricated girder, as shown in Fig. 14B In the state where the arrangement of the coated strand 70 is fixed by the grout material 60 hardened in the sheath tube 12, Since the prestress is introduced into the stranded wire 71 of the stranded wire 70, the coated stranded wire 70 can be maintained at the lower side of the sheathing tube 12 as shown in FIG. 14A. Therefore, when the prestress is introduced in the state that the same tensile force is introduced into the coated strand 70 in Fig. 14A and the strand 71 in Fig. 14B, the present invention (Fig. 14A) 70 can be made longer, the effect of increasing the eccentric moment for canceling the load acting on the bridge girders 1, 2 can be increased, and the resistance against the load can be further increased Effect can be obtained.

Above all, in the bridge girders 1 and 2 manufactured as described above, the grout material 60 is injected into the sheath tube 12 and cured before introducing the tension force P into the coated strand 70 The cover 72 of the coated strand 70 is integrated with the sheath tube 12 and the prestress is introduced so that the sheath tube 12 is not damaged during the introduction process of the prestress. Since the rust-preventive agent is not leaked even after the construction of the bridge even during the construction, the load-bearing ability at the time of construction can be maintained semi-permanently. Can be obtained.

In the bridge girders 1 and 2 manufactured as described above, the covered strand 70 extends straight without being deflected by its own weight at the end of the girder, and at the same time, It is not necessary to introduce a tension force to a part of the bundle of covered strands 70 as needed and it is necessary to improve the load carrying capacity by a vehicle increase or the like in the future, 70), it is possible to control the load-bearing capacity after the bridge construction.

In addition, since the girder 1, 2 constructed as described above is in a state in which the strand 71 is surrounded by the sheath 72, the strand 71 can be replaced at any time. That is, when a strand having a higher tensile strength becomes available after a lapse of time compared to the tensile strength of the strand 71 used at the time of construction of the bridge, and a new strand is separately installed outside the girder, It is possible to replace the existing strand 701 in the sheath pipe with a new strand 702 having a higher tensile strength and replace the strand 701 without replacing the girder to improve the load bearing capacity of the bridge.

16, a plurality of coated strands 70 are disposed in the sheath tube 12 of the girder and the space between the sheath tube 12 and the coated strand 70 is filled with the grout material 60, A method for maintaining a bridge girder according to an embodiment of the present invention (S200) including an arrangement for replacing an existing strand 701 with a new strand 702 in a bridge girder integrated by the above- .

Step 1 : First, the fixing state of the first coated strand, which is a part or more of a plurality of the coated strands fixed to the anchor head, is released (S210).

To this end, a hydraulic jack (not shown) is connected to the first strand 701 and the wedge member 230 is inserted into the second through hole 210a of the anchor head 210 in a state in which the first strand 701 is pulled by the hydraulic jack. And removes the tension force on the first strand 701 to be replaced among the strands fixed to the anchor head 210. [

Step 2 : Before or after step 1 is performed, the first strand 701 and the new second strand 702 to be removed in the first sheath of the sheath tube 12 are connected to the connector 300 (S220).

At this time, the first strand 701 and the second strand 702 are stranded wires formed by twisting a plurality of strands of wire or wires. The center strands 701a and 702a are located at the center of the strand, The center wire 701a of the first strand 701 is connected to the center wire 702a of the second strand 702 and the end face of the connector 300 is connected to the end face d ' . ≪ / RTI >

18A, the connector 300 includes a central body 310 and a first wedge 320 (not shown) which is fitted to one end of the center wire 701a of the first strand 701. [ A second wedge 320 'fitted to one end of the center wire 702a of the second strand 702 and a second wedge 320' A first casing 340 which receives one end and is coupled to one end of the center body 310 and a second casing that receives one end of the center wire 702a of the second wedge 320 'and the second strand 702, And a second casing 340 'coupled to the other end of the second casing 310.

Here, the cross-sectional size of the central body 310, the first casing 340, and the second casing 340 'is formed to be inserted into the first cover. A first spring 330 is installed between the center body 310 of the connector 300 and the first wedge 320 in a compressively deformed state so that the first wedge 320 is connected to the first strand 701, The center wire 701a of the wire 701a is stably held. Similarly, a second spring 330 'is provided in a compressively deformed state between the central body 310 of the connector 300 and the second wedge 320' so that the second wedge 320 is connected to the first strand 320 701 in the state of holding the center wire 701a.

18B, the connector 300 'includes a central body 310, a first end body 310 coupled to the center body 310 by a hinge 311a and capable of pivotal rotation r1 with respect to the center body 310, And a second end body 312 coupled by the hinge 312a and capable of pivotal rotation r1 with respect to the central body 310. [

The wedges 320 and 320 ', the springs 330 and 330', and the casings 340 and 340 'are provided on the respective end bodies 311 and 312, respectively, and the center of the first strand 701 And is fixedly engaged with the wire 701a and the center wire 702a of the second strand 702. [ Since the end portions 311 and 312 of the connector 300 'are provided so as to be pivotally rotatable with respect to the central body 310, even when the arrangement curvature of the strand 70 in the girder is large, An advantage of being able to smoothly replace the stranded wire by the rotation r1 is obtained.

In addition, each of the end bodies 311 and 312 may be provided with spin axes 311x and 312x that spin-rotate (r2) in the axial direction of the strand. Accordingly, during the replacement process of the strand, the first strand 701 is discharged from the first sheath and the second strand 702 is inserted into the first sheath after the first strand, so that the displacement, which is spin-rotated by friction, As a result, the replacement process of the stranded wire can be performed with less force. Although spin axes 311x and 312x for allowing spin rotation are formed in the end bodies 311 and 312 in the figure, according to another embodiment of the present invention, the spin axes 311x and 312x, which allow spin rotation, May be located at the center of the hinge (311a, 312a) of the body (310) and may be configured to allow spin rotation in the central body. That is, it suffices that at least one spin axis is provided between the first end body 311 and the second end body 312 so as to permit spin rotation.

Step 3 : Then, as shown in FIG. 19, one end of the first strand 701 is pulled out and the first strand 701 is extracted 701d outside the first cover (S230). At this time, since the second strand 702 is connected to the connector 300 at the other end of the first strand 701, the first strand 701 is discharged to the outside of the first strand 701 as shown in Fig. (701d), and a new second strand 702 is inserted (702d) into the first sheath.

Step 4 : Then, for the newly inserted second strand 702, similar to step S170 of FIG. 3, the second strand 702 is replaced and the tension force P is introduced, To the second through hole 210a (S240). At this time, since the second strand 702 is made of a material having a higher tensile strength than the first strand 701, it is possible to introduce a larger tensile force P into the second strand 702 to introduce a prestress Thus, the load carrying capacity of the girders 1, 2 can be further improved.

In the drawing, one first strand 701 is replaced. It is also possible to replace several strands 701 one by one by repeating steps 1 and 2, or to replace at least two first strands 701 ) Can be replaced at the same time and introduced into a prestressed manner.

As described above, in the present invention, since the strand in the cover can freely slide and move in the state that the cover 72 is fixed by the grouting material 60 in the sheath tube 12, the stranded strand 701 in the covering is replaced with a new strand The bridge 702 can be replaced with a stranded wire having a higher tensile strength even after completion of the construction of the bridge so that the advantageous effect of increasing the load-carrying capacity of the bridge in accordance with the trend of steel development after the construction Can be obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

1, 2: girder for bridge 10: concrete section
12: Sheath tube 100: Grouting device
110: trumpet member 120: support block
130: guide tube 140: push block
160: elastic ring 210: anchor head
230: wedge member 300: connector

Claims (22)

A girder preparing step of preparing a girder provided with a sheath pipe;
Inserting a plurality of coated strands formed in the sheath in such a manner that the strands are movable in the axial direction;
A support block mounting step of installing a support block having a first through hole passing through the coated strand at an end of the sheath tube and accommodating the elastic ring capable of being elastically deformed;
A guide tube installation step of installing guide tubes guiding the coated strand extending outward from the first through-hole of the support block;
A sealing step of expanding the elastic ring by pressing the elastic ring with the guide tube to fill the gap between the support block and the coated strand by the elastic deformation of the elastic ring to block the inner space of the sheath tube from the outside ;
A grouting step of pouring and curing a grout material into the sheath tube with the coated strand guided by the guide pipe after the sealing step so that the sheath of the coated strand is integrated with the grout material;
After the grouting step, the support block and the guide tube are separated from each other, and in the state where the strand of the end portion of the coated strand is exposed, the anchor head is inserted into the second through hole aligned with the first through- Installing an anchor head;
Introducing a prestress into the girder by pulling and fixing the strand through the second through-hole of the anchor head after the grout material is cured;
And a plurality of girders formed on the upper surface of the girders.
The method according to claim 1,
Wherein the first through hole is formed with a step, the elastic ring is disposed at the step, and the end of the guide pipe is inserted into the step.
3. The method of claim 2,
Wherein the guide tube guides the coated strand of each of the first through holes of the support block in an extending direction thereof in a linear direction.
3. The method of claim 2,
Wherein the guide pipe is formed of a metal.
3. The method of claim 2,
Wherein the guide tube is moved by a push block which accommodates a large number of guide tubes and moves the guide tubes toward or away from the girders.
3. The method of claim 2,
Wherein the coated strand is a strand in which a plurality of wires are twisted inside the sheath.
The method according to claim 1,
Wherein the step of introducing the prestress is performed after the grouting for a predetermined period after the grouting step.
delete 8. The method according to any one of claims 1 to 7,
A plurality of sheath pipes installed in the girders and a sheath pipe into which the coated strands are inserted are part of a plurality of sheath pipes installed on the girders and stranded wires having no sheath are provided in other parts of the plurality of sheath pipes Of the girder.
A girder for a bridge fabricated according to any one of claims 1 to 7.
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