JP4279189B2 - Temporary strut and its construction method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a temporary strut that is laid horizontally to support a structure having a slope and a construction method thereof.

  A cable-stayed bridge is a type of bridge that supports a main girder suspended by a cable (hereinafter sometimes referred to as “diagonal material”) that is slanted from the main tower. Due to its unique design and stability and the fact that the main girder is erected from diagonally extending from the main tower, it is installed in order, so there is little extra work, it is excellent in workability and relatively low in construction costs. The number of cases where Ohashi is built by cable-stayed bridges is increasing.

  The construction of the main tower of these cable-stayed bridges has a special shape and involves work at a high place, so various construction methods have been developed and put to practical use. For example, in Patent Document 1, when a main tower is constructed, tower cranes are installed at both ends of a climbing scaffold, and a stay for supporting the tower crane is repeatedly performed by sequentially carrying in materials and raising the formwork by the tower crane. A method for constructing a tower-like structure is described which eliminates the equipment costs associated with tower construction.

By the way, some of the main towers of these cable-stayed bridges often have slopes at the pillars, and when building pillar members with such slopes, the weight of the frame is Cracks due to the bending moment acting on the legs may occur. Therefore, when a column member having a conventional inclination is constructed, provisional struts (cut beams) are installed to cause a bending moment in the opposite direction to act on the leg portion, thereby reducing the stress applied to the column member. Similarly to these cable-stayed bridges, temporary struts may be installed when constructing a structure having an inclination.
JP 2003-328323 A ([0014]-[0019], FIG. 4)

  However, the provision of temporary struts is that the column members are inclined, the climbing scaffolds for building the frame are present, and there are limits to the shape of the members that can be suspended from this narrow space. Construction of the temporary strut itself was difficult due to the fact that the temporary strut itself was large and its weight sometimes exceeded the capacity of the crane.

  In addition, even when the temporary strut is installed through a narrow space by dividing it, usually, the divided temporary strut members are once mounted on the existing temporary strut and assembled on the existing temporary strut. Later, it was lifted and installed. In this case, since the total weight of the temporary struts is temporarily deposited in the existing temporary struts or the like, the members (brackets, etc.) for laying each temporary strut need to be resistant to the weight of the two temporary struts. It had the problem of becoming large-scale. Further, if the temporary struts are divided finely, there is a problem that the crane wires interfere with the climbing scaffold when the left and right end members are placed.

  In addition, when installing the temporary strut, the bracket to be installed as a cradle for the temporary strut is also slanted using a thick steel material having sufficient strength to support a large-scale temporary strut. Since the trapezoidal shape with the width of the bottom portion increased in accordance with the column member, the shape becomes large, so that the installation is complicated and the cost is increased.

  The present invention aims to solve the above-mentioned problems, and regarding the installation of temporary struts that support the column member during construction of the main tower of a cable-stayed bridge having an inclined column member, Temporary struts that can be carried into a predetermined position using only a small space, can be constructed without entrusting the entire weight to existing temporary struts, etc., and can be installed without requiring large-scale brackets. The problem is to propose a construction method.

In order to solve the above-mentioned problem, the invention according to claim 1 reduces the stress acting on the base end portion of the column member at the time of construction of at least two column members whose distances are narrowed upward. In order to do so, temporary struts that are laterally disposed between the pillar members, the strut members at both ends where the wire insertion members are arranged, and the central strut member where the wire fixing members are arranged are arranged in the longitudinal direction. The strut members adjacent to each other are connected in a foldable manner via hinge members .

  Since such a temporary strut has a configuration in which at least two strut members are connected in a foldable manner, even when a space for hanging the temporary strut by a climbing scaffold or the like is narrow, the temporary strut can be folded to pass through the narrow space. It becomes possible to hang it in a possible shape.

In addition , since the central strut member having the wire fixing member and the strut members at both ends having the wire insertion member are connected via the hinge member, a suspension wire for suspending the temporary strut (hereinafter referred to as “main strut member”). The wire is sometimes fixed to the central strut member, and the suspension wire for folding the strut member (hereinafter also referred to as “auxiliary wire”) is inserted into the wire insertion member and then fixed to the wire fixing member. For example, since the strut member can be lifted by rotating the hinge member around the shaft simply by lifting the main wire and the auxiliary wire, the temporary strut can be automatically folded. Further, after the temporary struts are suspended, the strut members that have been lifted simply by loosening the auxiliary wires spread and return to the original state, so that the temporary struts can be easily assembled.

The invention according to claim 2 is characterized in that the column member is arranged to reduce the stress acting on the base end portion of the column member at the time of construction of at least two column members whose distances are narrowed upward. A temporary strut laying method laterally disposed between the end portions of the temporary struts , wherein the left end portion and the right end portion are placed at predetermined positions between the two pillar members; wherein the central portion of the temporary struts after down hanging from above between said post member, said tentative strut assembly process the temporary struts assembled linearly, the temporary struts assembly process temporary struts assembled to the two in the and a temporary strut erection step of bridging between the pole members, said central portion has at least two strut members together are provided continuously in the longitudinal direction is being foldable connected, the temporary strike In Tsu DOO assembly process, after being lowered suspended between the end mounting the right end and the left end portion placed in position in about置工 in a state where the strut member is folded, the strut member Is opened, and the central part, the left end part and the right end part are integrally connected, and assembled in a straight line.

  Since the temporary strut is foldably connected by the temporary strut construction method, it can be hung at a predetermined position in a folded state. Therefore, even when the space for suspending the temporary strut using a tower crane or the like is narrow due to a scaffold or the like that is installed along with the construction of the main tower, it can be installed.

Further , when the temporary struts are divided and suspended, even if the width of the central part is secured relatively wide, if the central part is folded in a folded state, it is possible to pass through a narrow space. Therefore, it is possible to reduce the number of divisions of the temporary struts, and it is possible to reduce the labor required for assembling the temporary struts.

  Further, in the temporary strut installation step, if the temporary strut is suspended by a suspension member suspended from a predetermined position of the column member, it is constructed corresponding to the obliquely formed column member. It is possible to reduce the trouble of mounting the bracket whose shape is large and the material cost, and it is possible to reduce both the construction period and the construction cost.

  According to the present invention, it is possible to save labor for the construction work of the temporary strut when constructing the column member having an inclination, and it is possible to reduce the amount of steel material required for the construction of the temporary strut and improve the workability. It becomes.

  Preferred embodiments of the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted. Further, the front, rear, left and right in the description are determined as left and right as viewed from the front view of FIG. 1, and the front side is the front and the back side is the rear.

FIG. 1 is a front view showing a main tower 1 of a cable-stayed bridge constructed using the temporary strut erection method of the present invention, and FIG. 2 shows a situation after erection of a second temporary strut described later. It is a figure, (a) is a top view, (b) is a front view.
The main tower 1 is constructed on an oblique material fixing portion 2 to which an oblique material for suspending the main beam B is fixed, a pillar portion 3 that supports the oblique material fixing portion 2, and a pier portion P, and is built on the pillar. It is composed of a main tower base portion 4 that supports the portion 3. Here, the pillar part 3 is comprised by the two pillar members 5 and 5 which a mutual space | interval narrows as it goes upwards.

In the present embodiment, when constructing the column members 5, 5 of the main tower 1, three temporary struts 10, 20, 30 are installed between the column members 5, 5. The temporary struts 10, 20 and 30 reduce the stress applied to the main tower base 4 and the leg portions (base end portions) of the column members 5 and 5 when the column members 5 and 5 are constructed with an inclination. .
Here, the temporary struts 10, 20, 30 installed between the column members 5, 5 are referred to as a first temporary strut 10, a second temporary strut 20, and a third temporary strut 30 from the bottom.

  The main tower 1 is constructed from the bottom in the order of the main tower base 4, the column part 3, and the diagonal material fixing part 2. At this time, the climbing scaffold 60 used as a temporary work place or a temporary storage place for materials also rises in accordance with the rise of the construction site. Each material is carried into the climbing scaffold 60 by a tower crane (not shown).

  The temporary struts 10, 20, and 30 are installed at the stage where the column members 5 and 5 are constructed to a predetermined height above the installation positions of the temporary struts 10, 20, and 30, respectively. The first temporary strut 10 is installed by using brackets 40 and 40 fixed to the column members 5 and 5, and the second temporary strut 20 and the third temporary strut 30 are formed by using the suspension members 50 of the column members 5 and 5. It is built between. The temporary struts 10, 20, and 30 according to the present embodiment are fixed horizontally by generating a frictional force between the column members 5 and 5 by the pressure of the fixing members at the left and right ends. The suspension member 50 is a member for temporarily supporting the temporary struts 10, 20, and 30 when they are installed and removed. In addition, when the frictional force by the fixing member is small or when no pressure is applied, the bracket 40 and the suspension member 50 are members that always support the temporary struts 10, 20, and 30. The temporary struts 10, 20, and 30 are erected while hanging each member from a narrow space 61 formed at the center of the climbing scaffold 60 by a tower crane (see FIG. 2A).

  As shown in FIG. 2 (a), the second temporary strut 20 according to the present embodiment is installed between the pillar members 5 and 5 at two positions in the front and rear. Similarly, the first temporary strut 10 and the third temporary strut 30 are also erected at two places in the front and rear.

Next, the construction procedure of the temporary struts 10, 20, and 30 will be described with reference to FIGS. 3 to 7, taking the second temporary strut 20 as an example. Here, FIG. 3 is a flowchart showing a construction procedure of the second temporary strut 20. 4-7 is a figure which shows each construction step in construction work of a 2nd temporary strut, (a) is a top view, (b) is a front view.
As shown in FIG. 3, the temporary strut erection method according to the present embodiment includes an end placement step S1, a temporary strut assembly step S2, and a temporary strut erection step S3. By repeating the process, the second temporary struts 20 are installed at two front and rear positions of the column member 5 as shown in FIG.

[End placement process]
As shown in FIGS. 4 and 5, the end placement step S <b> 1 uses a narrow space 61 formed in the center of the climbing scaffold 60 to use the left divided strut 21 and the right divided strut 23 of the second temporary strut 20. Is temporarily placed on the upper surface of the first temporary strut 10. Here, the second temporary strut 20 is divided in advance into a left divided strut 21, a middle divided strut 22, and a right divided strut 23. The left divided strut 21 and the right divided strut 23 are symmetrically formed in substantially the same shape. Is formed.

As shown in FIG. 4A, the length of the left divided strut 21 is longer than the left and right widths and the front and rear depths of the narrow space 61, and when passing through the narrow space 61, the longitudinal direction of the left divided strut 21 is narrowed. By adjusting to the diagonal line of the space 61, the left divided strut 21 is suspended using a tower crane (not shown) while maintaining the level.
The left split strut 21 that has passed through the narrow space 61 is rotated so that its longitudinal direction is parallel to the first temporary strut 10 as shown in FIG. Temporary placement on one temporary strut 10. At this time, a sleeper 11 for temporarily placing the second temporary strut 20 is disposed on the upper surface of the first temporary strut 10 at a predetermined position.

  Subsequently, the right divided strut 23 is temporarily placed at a predetermined position on the first temporary strut 10 through the narrow space 61 by the same method as the left divided strut 21 (FIGS. 5A and 5B). )reference).

[Temporary strut assembly process]
In the temporary strut assembly step S2, the middle divided struts 22 are suspended between the left divided strut 21 and the right divided strut 23 temporarily placed on the upper surface of the first temporary strut 10 in the end placement step S1. This is a step of integrating the struts 21, 22, and 23 (see FIG. 6).

  As shown in FIG. 6 (b), the middle divided strut 22 has left and right strut members (hereinafter “wings” so that the width of the middle divided strut 22 is narrower than the width of the narrow space 61 when passing through the narrow space 61. The members 22b and 22b are suspended in a state of being folded upward at the folding point 24.

  Then, when the middle divided strut 22 passes through the narrow space 61, the left and right wing members 22b, 22b that are folded upward are spread horizontally, and after parallel translation as shown in FIG. 6 (a), It is placed between the left divided strut 21 and the right divided strut 23 temporarily placed on the first temporary strut 10. Then, the divided struts 21, 22, and 23 are integrally joined with bolts or the like to construct the second temporary strut 20. At this time, the middle divided strut 22 is operated with the main wire 51 for lifting extending from a tower crane (not shown) so that the weight of the second temporary strut 20 loaded on the first temporary strut 10 can be reduced. Thus, the burden on the first temporary strut 10 is preferably reduced.

[Temporary strut erection process]
The temporary strut installation step S3 is a step of installing the second temporary strut 20 assembled in the temporary strut assembly step S2 at a predetermined position of both the pillar members 5 and 5.

The second temporary strut 20 integrated on the upper surface of the first temporary strut 10 is lifted by the main wire 51 as shown in FIG. It will be erected. At this time, the second temporary strut 20 is fixed to the fixing member guide plates 41 and 41 previously installed at predetermined positions of the column members 5 and 5. 25, and positioning is performed in a state of being suspended by suspension members 50 and 50 suspended from predetermined positions above the fixing member guide plates 41 and 41, and is horizontally fixed by the fixing members 25 and 25. The fixing member 25 is composed of a hydraulic jack or the like having a telescopic function. The fixing member 25 extends between the left and right sides and is pressure-bonded to the column members 5 and 5 so that the fixing member 25 is connected to the column members 5 and 5. The second temporary strut 20 is fixed horizontally by the frictional force. In addition, the main wire 51 shall be arrange | positioned in consideration of the balance at the time of lifting of a 2nd temporary strut, and shall be supported by four points in this Embodiment.
Here, the suspension member 50 in the present embodiment is the time when the second temporary strut 20 is installed and removed, and the pressure by the fixing member 25 does not act on the column members 5 and 5, and the second temporary strut 20 A member that is temporarily suspended when not fixed. However, in the case of a temporary strut to be installed without applying pressure or a temporary strut to be installed in a pressure range where a frictional force sufficient to support its own weight cannot be obtained, it is not limited to this, and the suspension member 50 should always be suspended. It becomes.

  The same operation is repeated, and the second temporary strut is installed on the front side of the same height between the column members 5 and 5 (see FIG. 2A).

Note that the first temporary strut 10 and the third temporary strut 30 can be constructed by a method substantially similar to the construction method of the second temporary strut 20.
Here, when the second temporary strut 20 is installed, positioning is performed in a state of being suspended by the suspension members 50 and 50 in the temporary strut installation process. However, when the first temporary strut is installed, the second temporary strut 20 is fixed to the column members 5 and 5. The positioning is performed in a state where the first temporary strut is installed on the brackets 40 and 40.
Further, the temporary placement of the left and right divided struts during the assembly of the third temporary strut 30 can be performed on the upper surface of the second temporary strut 20.

Next, a detailed configuration of the middle divided strut 22 will be described.
FIG. 8 is an enlarged view of the folding point 24 of the middle split strut 22. As shown in FIG. 8, the middle split strut 22 includes a middle member (strut member) 22a and left and right wing members 22b, 22b is connected through a hinge member 26. Here, FIG. 8 shows only the folding point 24 between the middle member 22a and the right wing member 22b, but the middle divided strut 22 is configured symmetrically, and the middle member 22a and the left wing The break point 24 with the member 22b is similarly configured.

  With this configuration, the left and right wing members 22b and 22b can rotate 90 ° with respect to the middle member 22a. In addition, suspension pieces 27a and 27b are fixed to the intermediate member 22a and the wing member 22b, respectively, at a predetermined interval from the hinge member 26. When the middle split strut 22 is suspended, the auxiliary wire 29 has one end fixed to a shackle (wire fixing member) 28a attached to the suspension piece 27a of the intermediate member 22a, and the other end is The shank (wire insertion member) 28b of the suspension piece 27b fixed to the wing member 22b is inserted through the tower crane together with the main wire 51 (see FIG. 6B). With this configuration, when the auxiliary wire 29 is lifted, the suspension piece 27b fixed to the wing member 22b is pulled upward in the center. Therefore, the wing member 22b is rotated upward about the hinge member 26 and rises upward. . Further, when the middle divided strut 22 is placed between the left divided strut 21 and the right divided strut 23 and the tension of the auxiliary wire 29 is loosened, the wing member 22b that has been pulled upward spreads horizontally, and the middle divided strut is expanded. 22 can be connected to the left and right divided struts 21 and 23.

  As described above, the temporary strut erection method of the present invention divides the temporary strut into three sizes that can pass through the narrow space 61 formed in the center of the climbing scaffold 60. The work can be performed without the wire 51 interfering with the climbing scaffold. Further, since the middle divided strut 22 has the folding point 24, even if the width of the middle divided strut 22 is configured to be somewhat wide, the narrow space 61 can be formed by raising both wings 22b upward at the folding point 24. It can pass.

  Further, according to the configuration of the break point of the middle divided strut 22, the wing 22b rises by being lifted by the auxiliary wire 29, and the wing 22b expands by being placed at a predetermined position. It is possible to carry in the middle divided strut 22 without requiring any personnel.

  In addition, by using the suspension member 50 as a temporary strut erection member, it is possible to reduce the labor and steel cost required for the installation work of the bracket whose bottom extends in accordance with the inclination of the column member 5. Moreover, since the installation using the suspension member 50 is completed by simply lifting the temporary strut vertically and then attaching the suspension member 50 to a predetermined position of the temporary strut, the bracket is moved by moving the temporary strut back and forth. Compared with the method of temporarily raising the temporary strut to a position higher than the bracket and then returning the front and rear positions of the temporary strut and placing them on the bracket, the operation is easier.

As mentioned above, although preferred embodiment was described about this invention, this invention is not limited to the said embodiment, A design change is possible suitably in the range which does not deviate from the meaning of this invention.
For example, in the above embodiment, the construction method of the temporary strut according to the present invention is adopted for the construction of the column having the inclination of the main tower of the cable-stayed bridge. Needless to say, it is not limited to the main tower of the cable-stayed bridge.
In the above embodiment, the two pillars are inclined with respect to each other. However, the present invention is not limited to this. A structure in which either one has an inclination and the distance between the two pillars becomes narrower as it goes upward. The construction method of the temporary strut of the present invention may be applied at the time of construction.

In the above embodiment, the first temporary strut is installed via the brackets fixed to the left and right column members. However, like the second temporary strut and the third temporary strut, the first temporary strut is installed by the suspension member. The member used for the construction may not be limited.
In addition, the suspension member for suspending each temporary strut is not limited in form, shape, etc., and is appropriately selected from those having the ability to suspend temporary struts according to the situation at the site. To use.

In the above-described embodiment, the temporary strut is divided into three parts and is assembled after being suspended between the column members. However, the number of temporary struts is not limited, and the temporary strut assembly process is not limited. It is set as appropriate in consideration of the strength of the existing members to be placed, the effort required for the assembly work, the capacity of the lifting machine, and the like.
In the above embodiment, three temporary struts are installed. However, the number of temporary struts to be installed is limited as long as the stress acting on the base ends of the left and right column members can be controlled. Is not to be done. Similarly, two temporary struts are installed in the front-rear direction, but the number of temporary struts to be installed is not limited, and is appropriately set according to the structure of the column member and the like.

Moreover, in the said embodiment, although it was set as the structure which folds a middle division strut by two right and left with a hinge member, if the middle division strut is folded so that it can pass through a narrow space, the system and the number of places will be limited. It is not something.
In the above embodiment, the auxiliary wire is pulled up using the main wire and both wings are pulled up. However, for example, the wings may be manually opened and closed, and the method is limited. Is not to be done.
In the above embodiment, the wire insertion member is installed in the left and right wing members and the wire fixing member is installed in the middle member. For example, the wire fixing members are installed in the left and right wing members in the same manner as the middle member. The configuration of the joint between the middle member and the wing member is such that the wing member is pulled up and folded by fixing the shorter suspending wire to the left and right wing members and the longer suspending wire to the middle member, respectively. It is not limited.
Furthermore, the method for joining the divided struts is not limited to fastening with bolts.

It is a front view which shows the main tower of a cable-stayed bridge constructed | assembled using the construction method of the temporary strut of this invention. It is a figure which shows the condition after construction of the 2nd temporary strut in the construction method of a temporary strut, (a) is a top view, (b) is a front view. It is a flowchart which shows the work procedure of the construction method of the temporary strut of this invention. It is a figure which shows the suspension procedure of the left end part in the construction method of a temporary strut, (a) is a top view, (b) is a front view. It is a figure which shows the temporary placement condition of the left end part and right end part in the construction method of a temporary strut, (a) is a top view, (b) is a front view. It is a figure which shows the mounting procedure of the center part in the construction method of a temporary strut, (a) is a top view, (b) is a front view. It is a figure which shows the construction procedure of the 2nd temporary strut in the construction method of a temporary strut, (a) is a top view, (b) is a front view. It is a figure which shows the detail of the folding point of the center part of a 2nd temporary strut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main tower 2 Diagonal material fixing part 3 Column part 4 Main tower base part 5 Column member 10 1st temporary strut 20 2nd temporary strut 21 Left division strut (left end part)
22 Middle split strut (central part)
22a Middle member (strut member)
22b Wing member (Strut member)
23 Right split strut (right end)
24 Folding point 26 Hinge member 27a Hanging piece (wire fixing member)
27b Hanging piece (wire insertion member)
28a Shackle (wire fixing member)
28b Shackle (wire insertion member)
29 Auxiliary wire 30 Third temporary strut 50 Suspension member 51 Main wire 61 Narrow space B Main girder P Bridge pier

Claims (3)

This is a temporary strut that is provided between the column members in order to reduce the stress acting on the base end of the column member when constructing at least two column members whose distance from each other becomes narrower upward. And
The central strut member in which the wire fixing member is disposed and the strut members at both ends in which the wire insertion member is disposed are continuously provided in the longitudinal direction.
The temporary struts, wherein the adjacent strut members are foldably connected via a hinge member . Temporary struts installed between the column members in order to reduce the stress acting on the base end portion of the column members when constructing at least two column members whose distances are narrowed toward the upper side Construction method,
An end portion placing step of placing the left end portion and the right end portion of the temporary strut at a predetermined position between the two column members;
A central portion of the temporary struts after down hanging from above between said post member, and a temporary strut assembly process for assembling the temporary struts linearly,
A temporary strut erection step of laying the temporary struts assembled in the temporary strut assembly step between the two column members,
The central portion is formed by connecting at least two strut members connected in a longitudinal direction in a foldable manner,
In the temporary strut assembly step, after the strut member is folded, the strut member is suspended between the left end portion and the right end portion placed at a predetermined position in the end portion placing step, and then the strut member A temporary strut erection method, wherein a member is opened and the central portion, the left end portion, and the right end portion are integrally connected to each other and assembled linearly. The temporary strut erection method according to claim 2 , wherein in the temporary strut erection step, the temporary strut is suspended by a suspending member suspended from a predetermined position of the column member.

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