JPH11181725A - Method for constructing horizontal beam of main tower made of concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reuse a timbering girder to a another usage and to move the timbering girder upward to a predetermined part without moving it sideways. SOLUTION: A bracket 13, a timbering girder 15, a form 17, and the like which are used in the construction of a horizontal beam 7 are conveyed to a predetermined part of a main tower 5. These members are assembled together to provide the bracket 13 on the outside wall of the main tower 5 and to erect the timbering girder 15 on the top of the bracket 13 provided on time side walls of the tower column 5 which extend in the same direction. A plurality of precast blocks 21 constituting the horizontal beam 7 are hoisted to a predetermined part and are bonded together via an adhesive to form a beam 37 having a length smaller than the clearance between the tower columns 5. A joint part 51 made of reinforced concrete to join the tower columns 5 with the beam 37 is provided in the gap 47 between each end of the beam 37 and the side wall of the tower column 5, and after the horizontal beam 7 is extended between the tower columns 5, the strand 55 of the entire horizontal beam 7 is tensioned to form a prestressed horizontal beam 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a horizontal beam of a concrete main tower, and more particularly to a method of constructing a horizontal beam provided on a main tower of a suspension bridge or a cable-stayed bridge.

[0002]

2. Description of the Related Art A main tower for supporting a suspension bridge cable high in the air or a main tower for hanging a girder in the middle of a span by a cable of a cable-stayed bridge stretched diagonally in a straight line generally comprises a tower column and a horizontal beam. ing. That is, the main tower has a column having a predetermined gap in the upper part of the foundation, and a plurality of horizontal beams with a predetermined gap in the vertical direction spanned between the columns.

Various construction methods have already been proposed as methods for providing horizontal beams between tower columns. For example, FIG. 7 is a view showing the first construction method, and FIG. 7A shows a front view of the main tower 1 and, as shown in FIG.
A supporting girder 61 is erected on a bracket 13 temporarily provided on the upper part of the tower column 5, and as shown in FIG. Is performed to provide a horizontal beam 7 at a predetermined position between the two tower columns 5. Then, as shown in FIG. 8C, after the jack 11 for hanging the support girder 61 is installed on the horizontal beam 7, the support girder 61 is hung above the existing horizontal beam 7 below the horizontal girder 7. take down.

FIG. 1D shows the main tower 1 shown in FIG. 1C.
As shown in the figure, the support girder 61 is dismantled to such an extent that it can be hung by a crane (not shown), and is located outside the side wall of the horizontal beam 7 and has two towers. The column 5 is moved outside the side wall. The support girders 61 may be disassembled after the support girders 61 are moved.

[0005] Then, as shown in Fig. 1 (e), the dismantled support girder 61a is lifted to a predetermined position by a crane (not shown). FIG. 8 is a diagram showing a second construction method of the horizontal beam 7 already proposed, wherein FIG. 8A shows a front view of the main tower 1, and FIG. 8B shows a diagram (a). Main tower 1 shown
FIG. As shown in FIGS.
An overhanging girder 63 is temporarily provided on the tower pillar 5, and a jack 11 is provided on the overhanging girder 63. The jack 11 lifts the support girder 61, the formwork, and the reinforcing bar. Then, these are laterally moved to a predetermined portion.

Next, as shown in FIG. 1C, a horizontal beam 7 is provided at a predetermined position between the two tower columns 5 by performing a reinforcing work or the like on an upper part of the support girder 61. Then, FIG.
As shown in (e), the jack 1 provided on the horizontal beam 7
In step 1, the support girder 61 is hung above the existing horizontal beam 7 below and moved laterally there. Note that the support girder 61 may be moved laterally at the current height.

[0007] Then, as shown in Fig. 1 (f), the supporting girder 61 is lifted to a predetermined height by the jack 11 provided on the overhanging girder 63 temporarily provided above. FIG. 9 is a diagram showing a third method of constructing a horizontal beam which has already been proposed. FIG. 9 (a) shows a front view of the main tower 1, and FIG. 9 (b) shows a diagram of FIG. 1 shows a side view of the main tower 1 shown. As shown in FIGS. 7A and 7B, an overhang girder 63 is temporarily provided at the upper part of the tower post 5, and a jack 11 is provided on the overhang girder 63. After being lifted to the height, it is moved laterally to a predetermined site. Then, as shown in FIG. 3C, the supporting girder 61 is embedded in concrete as a part of the horizontal beam 7 to form a predetermined horizontal beam 7.

FIG. 10 is a view showing a fourth method of constructing a horizontal beam which has already been proposed, and FIG.
FIG. 2B shows a side view of the main tower 1 shown in FIG. As shown in FIGS. 7A and 7B, the precast concrete member 65 is lifted upward by a jack 11 provided on the overhanging beam 63 to a predetermined portion where the horizontal beam 7 is erected, and is laterally moved. As shown in FIG. 5C, a precast concrete member 65 is temporarily placed on the upper part of the bracket 67, and concrete is poured into a gap 69 between the outer ends of both ends of the precast concrete member 65 and the side wall of the tower 5. After the horizontal beam 7 is formed and the concrete is hardened, a prestress is applied to the entire horizontal beam 7 so that the precast concrete member 65 and the hardened concrete are tightened and integrated.

[0009]

However, according to the conventional first and second horizontal beam construction methods, when a new horizontal beam is constructed further above the horizontal beam after the construction of the horizontal beam, If the work girder is moved upward as it is, the constructed horizontal beam hinders the movement of the support girder to a predetermined position.

Therefore, in order to move the shoring girder to a predetermined portion, it is necessary to laterally move the shoring girder. In addition, since the horizontal beam is subjected to cast-in-place construction for formwork, reinforcing steel work, concrete work, and curing at a predetermined portion, the construction period is long.

Further, according to the third conventional method for constructing a horizontal beam, since each supporting beam is required for the horizontal beam, there is a problem that the supporting beam cannot be diverted.
Further, according to the fourth conventional method of constructing a horizontal beam, a temporary overhang girder for lifting the precast concrete member upward is required, and since the weight of the precast concrete member is large, the overhang girder becomes large. There is a problem in that the fixing means for fixing the overhanging girder to the tower pillar also becomes large-scale.

[0012] The present invention has been made in view of the above-mentioned matters, and can be diverted to a support girder, and moves the support girder to a predetermined height without moving laterally when moving the support girder upward. It is an object of the present invention to provide a method of constructing a horizontal beam of a concrete main tower in which a girder supporting a precast concrete member can be reduced in size and a fixing means for fixing the girder to a tower column can be reduced in size.

[0013]

The present invention has the following features to attain the object mentioned above. The present invention relates to the construction of a horizontal beam of a concrete main tower in which a concrete main tower is constructed by providing a plurality (n) of horizontal beams at predetermined intervals in a vertical direction between tower columns erected on a foundation. In the law,
(A) a member transporting step of transporting a member used when constructing the horizontal beam to a predetermined portion of the tower column; and (b) assembling the member transported in the member transporting step to a predetermined portion. A horizontal beam construction preparation step of preparing a horizontal beam by providing a shoring girder; and (c) lifting a plurality of constituent blocks constituting the horizontal beam to a predetermined portion and bonding these constituent blocks together to form a tower. A beam having a length smaller than the distance between the columns is formed, and a continuous portion for continuously connecting the column and the beam is provided in a gap between both ends of the beam and the side wall of the column. A horizontal beam erection step of applying a compressive load to this horizontal beam after laying a horizontal beam between the horizontal beams and having a prestressed horizontal beam,
(D) A horizontal beam extension process in which a cycle of performing the horizontal beam erection process after moving the support girder to a predetermined position above the horizontal beam erected in the horizontal beam erection process is repeated (n-1) times And a horizontal beam for the concrete main tower.

The number of horizontal beams formed on the main tower may be two or more. That is, "n" n is a natural number of 2 or more. Since the shoring girder is provided so as to be able to move up and down outside the tower pillar, when moving the shoring girder upward, the constructed horizontal beam does not hinder the upward movement of the shoring girder. .

Further, the continuous portion in the horizontal beam erection step may be formed of a resin gap insertion member. When the gap between both ends of the beam and the side wall of the column is small, the beam can be easily connected to the column by filling the gap insertion member made of resin.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for constructing a horizontal beam of a concrete tower according to the present invention (hereinafter referred to as "method of constructing a horizontal beam") according to the present invention is shown in FIGS. It will be described based on the following.

The present embodiment is an embodiment showing a method of constructing a horizontal beam provided between columns of a main tower of a suspension bridge or a cable-stayed bridge. First, a main tower constructed using the horizontal beam construction method of the present invention will be described with reference to FIGS.

FIG. 1A is a front view of the main tower 1, and FIG. 1B is a side view of the main tower 1. As shown in FIGS. 1A and 1B, two reinforced concrete tower columns 5 are provided upright on a reinforced concrete foundation 3 with a certain gap left and right. . Five horizontal beams 7 made of reinforced concrete are arranged between the two tower columns 5 and on the upper part of the foundation 3 with a predetermined spacing.

FIG. 2A is a front view of the horizontal beam 7, and FIG. 2B is a sectional view taken along the line AA of FIG. 2A. As shown in FIGS. 7A and 7B, the horizontal beam 7 has a through-hole 8 inside and has a rectangular parallelepiped shape.

Next, a method of constructing the horizontal beam 7 according to the present invention will be described with reference to FIGS. The construction method of the horizontal beam 7 includes a member transporting process, a horizontal beam construction preparation process, a horizontal beam erection process, and a horizontal beam extension process.

First, FIG. 3 (a) shows a front view of the main tower 1, and as shown in FIG. 3, a crane 9 which can be extended upward is installed at the upper edge of the foundation 3, and this crane 9 is installed. The two reinforced concrete tower columns 5 having a certain gap are provided on the side of the crane 9 by using the crane 9. The tower column 5 has a height higher than a portion where the first horizontal beam 7 from the bottom is provided. In addition, the construction of the first stage horizontal beam 7 may be started after the height of the tower column 5 is erected at the height where the horizontal beam 7 for several stages is erected.

Next, a member conveying step is performed. That is, the bracket 13, the support girder 15, and the plurality of molds 17 are lifted up to the position where the first-stage horizontal beam 7 is provided by using the jack 11 provided on the upper part of the tower column 5.

Next, a horizontal beam construction preparation process is performed. That is, FIG. 3B shows a side view of the main tower 1, and as shown in FIG. 3, brackets 13 are provided on the side walls 5 a and 5 b of the tower 5, and provided on the side walls of the tower 5 in the same direction. Bracket 1
A shoring girder 15 is erected on the upper part of 3.

FIG. 4 is a side view of a part corresponding to the view taken in the direction of arrows BB in FIG. 3 (a). As shown in FIG. 4, a support portion 13a having a substantially Y-shaped side surface and a support portion 13a The lower end of the support portion 13a of the bracket 13 having a plate-shaped mounting portion 13b provided on the upper portion of the
a, 5b, a plurality of PC steel members 19 penetrating through the tower column 5 are connected between the mounting portions 13b arranged on both left and right sides of the tower column 5, and the PC steel members 19 are tensioned to mount the bracket 13 on the tower. Fix to pillar 5.

Then, a box-shaped support girder 15 made of iron is extended above the mounting portion 13b and outside the tower post 5. In addition to the box shape, the support girder 15 may be a structure in which two I-type girders are arranged in parallel or a structure in which two trusses are arranged in parallel.

Next, a horizontal beam erection step is performed. That is, a precast block (constituting block) 21 which is a component part of the horizontal beam 7 is connected to a suspension girder 25 via two ropes 23, and another rope 2 is attached to the suspension girder 25.
7 is connected. The rope 23 may use a steel bar.

Here, the precast block 21 is plate-shaped, and a rectangular hole 29 is provided at the center thereof, and a hole 31 formed in a vertical direction through which the rope 23 is inserted is provided above the precast block 21. Is provided. The precast block 2 is provided on the upper wall surface and the lower inner wall surface of the precast block 21 or the inner surface of the vertical side wall.
1 is formed with an insertion hole 35 for inserting a temporary PC steel rod 49 for integrating the same. This precast block 2
By arranging a plurality of 1s, a rectangular parallelepiped beam 37 having a through hole 8 therein is formed.

The hanging girder 25 has a rod shape, and a hook portion 39 for hanging the rope 27 connected to the crane 9 is formed at the upper center thereof. A hole 41 for fixing the rope 23 connected to the precast block 21 is provided at an outer portion having a certain separation dimension. A bogie 43 is provided below the both ends of the suspension girder 25.

The carriage 43 is mounted on the support girder 15 and can move on the support girder 15 to move the suspension girder 25 to any position between the tower columns 5. Next, the rope 27 was hooked on the hook 45 of the crane 9, and the crane 9 was operated to provide the precast block 21 under the hanging girder 25 at the both ends below the hanging girder 25 in a suspended state. The truck 43 is placed on the support girder 15. Then, as shown in FIG. 5, the suspension girder 25 is moved so that the precast block 21 comes to a portion having a gap 47 having a predetermined interval W from the inner side wall of the left column 5.

Next, another precast block 21 is arranged at a predetermined position on the right side of the precast block 21 in the same procedure as that for the precast block 21. Then, after applying an adhesive to opposing wall surfaces of these precast blocks 21, the precast block 21 disposed later is moved to the left side via the carriage 43 to contact the wall surface of the pre-installed precast block 21. After that, the temporary P is inserted into the insertion holes 35 provided in the upper and lower portions or the side surfaces of the precast block 21.
The C steel bar 49 is inserted and tightened to integrate the adjacent precast blocks 21.

When using a material having a long pot life of the adhesive applied to the wall surface, several precast blocks 21 can be integrated at once at a time. Then, the precast block 21 is arranged on the right side of the integrated precast block 21 by the same method as described above, and the rectangular parallelepiped beam 37 is formed. A predetermined gap 4 is provided between the right end of the beam 37 and the inner wall surface of the right column 5.
7 are provided.

Next, in a gap 47 on both the left side and the right side of the beam 37, a so-called filling work is performed in which a continuous portion 51 for continuously connecting the beam 37 and the tower 5 is formed. That is, the form 17 is assembled in the gap 47, and a reinforcing bar is arranged inside the assembled form 17 to form a frame.
And a sheath 53 communicating between the sheath 53. Then, after the concrete is poured into the frame, the concrete is cured and the mold 17 is removed to form the continuous portion 51.

The connecting portion 51 is not limited to the above-described reinforced concrete, but may be formed by filling the gap 47 with a resin gap inserting member. An example of the resin gap insertion member is epoxy mortar.

Next, the strand 55 is made to penetrate the one column 5, and the inside of the sheath 53 of the one connecting portion 51 is inserted through the beam 3.
7 is inserted into the sheath 53 of the other connecting portion 53 so as to penetrate the other column 5. A plurality of strands 55 are provided and provided not only at the bottom but also at the top of the horizontal beam 7 (not shown). Also, it may be provided on the side wall.

Then, the strand 55 is tensioned to apply a compressive load to the horizontal beam 7 to form the first-stage horizontal beam 7 having prestress. Next, as shown in FIGS. 6A and 6B, the rope 2 connected to the precast block 21
3 is released, and the suspension girder 25, the trolley 43 and the suspension girder 25 are released.
After lifting up the rope 23 connected to the ground by the crane 9, a release step of hanging these 23, 25, 43 on the ground is performed.

Next, a horizontal beam extension step is performed. That is, as shown in FIG. 6C, P
The tension of the C steel material 19 is released, the connection of the support girder 15 to the tower 5 is released, and the bracket 13 and the support girder 15 are moved to a predetermined position above the first-stage horizontal beam 7. These movements are performed by jacks 11 provided on the tower 5 above the horizontal beams 7 of the first stage. Then, the horizontal beam erection step is performed.

The support girder 15 and the like may be moved by moving the support girder 15 and the like arranged on both sides of the tower 5 at the same time, or by moving one of them and then moving the other. Good.

The cycle consisting of the releasing step and the horizontal beam extension step is repeated four times, and four horizontal beams 7 having a predetermined gap in the vertical direction above the first horizontal beam 7 are installed between the tower columns 5. Then, a total of five horizontal beams 7 are provided between the tower columns 5.

Next, after performing the releasing step, the tension of the PC steel material 19 connecting the brackets 13 is released, the connection of the support girder 15 to the tower 5 is released, and these are placed on the ground by the jack 13. Hang it down.

[0040]

As described above, according to the present invention,
Since the shoring girder is provided to be able to move up and down on the outside of the tower post, when moving the shoring girder upward, the newly constructed horizontal beam does not disturb and hinder the movement, The support girders and the like can be moved upward collectively.

Therefore, the lateral movement of the shoring girder becomes unnecessary,
Eliminating the construction of the overhanging girder for moving the shoring girder upward and the overhanging girder for lateral movement becomes unnecessary.
Eliminating the need for access scaffolding and work scaffolding for these erection works reduces the need for work at heights and further improves safety, shortens the construction period of horizontal beams, and reduces the overall construction of the main tower. The period is shortened and the number of temporary materials is reduced as compared with the prior art.

Further, since the support girder can be hung on the ground without laterally moving after the uppermost horizontal beam is constructed, the removal work is extremely easy. Furthermore, the shoring girder is used for the construction of each horizontal beam, and the shoring girder can be diverted compared to the conventional technology in which the shoring girder is buried in concrete and part of the horizontal beam. Become.

Further, since the horizontal beam has a plurality of constituent blocks and these constituent blocks are formed of a lightweight material,
The building block can be lifted by a crane, and a beam for temporarily installing a large precast member and a large fixing means for fixing the beam to the tower are not required.

Further, since the constituent blocks are precast members, quality control is easy and a high-quality concrete member can be manufactured, and concrete placing work at a high place is reduced, and the supply control of concrete is facilitated.

[Brief description of the drawings]

FIG. 1 shows a main tower constructed by using a method of constructing a horizontal beam of a concrete main tower according to an embodiment of the present invention, and FIG. 1 (a) is a front view of the main tower. (B) is a side view of the main tower.

FIG. 2 shows a horizontal beam erected by a method of constructing a horizontal beam of a concrete main tower according to an embodiment of the present invention. FIG. 2 (a) is a front view of the horizontal beam, and FIG. FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a view showing one step of a method of constructing a horizontal beam of a concrete main tower in one embodiment of the present invention, and FIG. 3 (a) is a front view showing construction of a first-stage horizontal beam; And
FIG. 2B is a side view of FIG.

FIG. 4 is a side view of a part corresponding to the direction of arrow BB in FIG. 3 (a) of the method for constructing a horizontal beam of a concrete main tower in one embodiment of the present invention.

FIG. 5 is a front view showing a horizontal beam erection step of the method of constructing a horizontal beam of a concrete main tower in one embodiment of the present invention.

FIG. 6 is a view showing a part of a horizontal beam extension step in a method of constructing a horizontal beam of a concrete main tower according to an embodiment of the present invention.

FIG. 7 is a view showing a construction method of a horizontal beam of a concrete main tower according to the prior art.

FIG. 8 is a view showing a method of constructing a horizontal beam of a conventional concrete main tower.

FIG. 9 is a view showing a method of constructing a horizontal beam of a concrete main tower according to the prior art.

FIG. 10 is a view showing a construction method of a horizontal beam of a concrete main tower according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main tower (concrete main tower) 3 Foundation 5 Tower pillar 7 Horizontal beam 13 Bracket (member) 15 Supporting girder (member) 17 Formwork (member) 21 Precast block (composition block) 37 Beam 51 Connecting part

Claims (2)

[Claims] A concrete main tower is constructed by constructing a concrete main tower by providing a plurality (n) of horizontal beams at predetermined intervals in the vertical direction between tower columns erected on a foundation. In the construction method, (a) a member transporting step of transporting a member used when constructing the horizontal beam to a predetermined portion of the tower post; and (b) assembling the member transported in the member transporting step. A horizontal beam construction preparation step of providing a support girder at a predetermined location to prepare for the construction of a horizontal beam; and (c) lifting a plurality of component blocks constituting the horizontal beam at a predetermined location, and A beam having a length smaller than the separation dimension between the tower columns is formed by bonding, and a connecting portion for continuously connecting the tower column and the beam to the gap between both ends of the beam and the side wall of the column is formed. After installing a horizontal beam between the tower columns, a compressive load is applied to this horizontal beam to A horizontal beam erection step of forming a horizontal beam having a restless; and (d) a horizontal beam erection step after moving the support girder to a predetermined portion above the horizontal beam erected in the horizontal beam erection step. A horizontal beam extension step of repeating a cycle to be performed (n-1) times, and a method of constructing a horizontal beam of a concrete main tower, comprising: 2. The connecting part in the horizontal beam erection step is made of a resin-made gap insertion member.
The construction method of the horizontal beam of the concrete main tower described.