Method for suspending long member

Abstract

To suppress deflection deformation of a long member during construction when the long member is suspended using supports and to reduce residual stress in a steel material attached to the long member.SOLUTION: In a method for suspending a long member, the long member is suspended by a support structure via a plurality of suspending members, the support structure is installed above the long member, which is suspended approximately horizontally across a pair of support members, so as to be parallel to the longitudinal direction of the long member, and the support structure is provided with a plurality of tension adjustment mechanisms in the longitudinal direction for each of the plurality of suspending members, which adjust the tension generated in the suspending members, and one end of each of the plurality of suspending members is connected to each of the plurality of tension adjustment mechanisms, and the other end is connected to a plurality of locations in the longitudinal direction of the long member, and tension control is performed so that the tension generated in the plurality of suspending members is the same, and the long member is hung horizontally.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for suspending a long member.

Background Art

[0002] For example, when constructing the top plate of a wastewater treatment facility, or when constructing an elevated bridge above an existing facility such as the top plate of an underground storage or an excavated tunnel, a long member is spanned between columns using shoring, and concrete is placed thereon for construction.

[0003] For example, Patent Document 1 discloses a reverse casting method in which a precast body is constructed in a predetermined area, the area below the precast body is excavated and waste concrete is placed, and a formwork, a support member, a support means, etc. for constructing a post-cast body are provided below the precast body. The weight of the post-cast body is supported by the precast body via the support means, and the formwork and the like are disassembled. As this support means, a suspension hardware and a shaft member connected thereto are disclosed, and it is disclosed that a tension adjustment means for tensioning or releasing the tension of the shaft member is provided.

[0004] Also, when constructing an elevated bridge above an existing facility, for the purpose of labor and personnel savings at the site, it is known that a slab-shaped member made of half-precast concrete, which combines precast members and in-situ concrete members, is used. For example, members such as the top plate, beam member, and column member of a structure are fabricated by combining two concrete members (precast concrete member and in-situ concrete member).

[0005] For example, Patent Document 2 discloses a construction method in which a half-precast member is spanned as a beam between supports such as columns, and concrete is placed thereon. In Patent Document 2, the amount of prestress introduced into the half-precast member is calculated to ensure the flatness of the concrete structure horizontally spanned between the supports.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 1 above, a lower member is suspended by a preceding body to support a post-cast body, and by providing a tension adjusting means for a shaft member which is the supporting means, the supporting force can be freely adjusted. However, there is no mention of the deflection deformation when a load is applied to the preceding body or the influence on the supporting means due to the deflection, and there is room for further improvement in construction accuracy.

[0008] In Patent Document 2 above, a construction method of a concrete structure in which the cumulative deflection is made substantially zero is disclosed in consideration of the deflection due to the self-weight of a half-precast member. However, there is no mention of a configuration in which a beam member is suspended by an upper member such as a shoring, and construction management capable of effectively controlling deformation when deflection deformation occurs in the half-precast member when concrete is placed is desired.

[0009] In view of the above circumstances, an object of the present invention is to provide a method for suspending a long member that can suppress the deflection deformation of the long member during construction and reduce the residual stress of the steel material attached to the long member when constructing by suspending the long member using a shoring.

Means for Solving the Problems

[0010] In order to achieve the above object, according to the present invention, there is provided a method for suspending a long member by a shoring worker via a plurality of suspension members, the method comprising: installing the shoring worker above the long member laid horizontally across a pair of support members so as to be parallel to the longitudinal direction of the long member; providing a plurality of tension adjustment mechanisms for adjusting the tension generated in the suspension members to each of the plurality of suspension members in the longitudinal direction; connecting one end of each of the plurality of suspension members to each of the plurality of tension adjustment mechanisms respectively, and connecting the other end of each of the plurality of suspension members to a plurality of locations in the longitudinal direction of the long member respectively; performing tension control so that the tensions generated in the plurality of suspension members are the same as each other; and suspending the long member horizontally.

[0011] The long member is a half-precast member. When placing in-situ concrete above the half-precast member to construct an in-situ concrete part, tension control may be performed so that the tensions generated in the plurality of suspension members are kept the same when the tensions generated in the plurality of suspension members change.

Advantages of the Invention

[0012] According to the present invention, when suspending a long member using a shoring worker for construction, it is possible to suppress the deflection deformation of the long member during construction and reduce the residual stress of the steel material attached to the long member.

[0013] Note that the above effects are not necessarily limited. Together with or instead of the above effects, any of the effects shown in this specification or other effects that can be grasped from this specification may be achieved.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, for components having substantially the same functional configuration, the same reference numerals may be given to omit redundant explanations. Note that the structure using the method for suspending a long member according to the present invention is arbitrary, but as an example, in this embodiment, the case of constructing the top slab of a culvert will be illustrated and described. Further, in the embodiments of this specification, for the purpose of explanation, the reinforcing bar structure and the reinforcement configuration may be partially omitted from the illustration, or the reinforcing bars inside the member may be illustrated.

[0016] In the following description, in the culvert, the direction in which the internal space extends is defined as the "length direction" of the culvert, the direction orthogonal to the length direction so as to cross the internal space is defined as the "width direction" of the culvert, and the direction orthogonal to these length direction and width direction is defined as the "height direction". In the drawings, the length direction may be illustrated as the "Y-axis", the width direction as the "X-axis", and the height direction as the "Z-axis".

[0017] <Configuration of the Top Slab Structure> FIG. 1 and FIG. 2 are schematic explanatory views of the top plate structure 1 according to an embodiment of the present invention, FIG. 1 is a schematic plan view, and FIG. 2 is a schematic side sectional view. Note that this top plate structure 1 is an example of a slab-shaped member that is supported by, for example, the side walls of a culvert as support members and is mounted across a plurality of support members. Here, in FIG. 2, for the sake of explanation, in addition to the top plate structure 1, support members (support members 10 described later) and a shoring work (shoring work 30 described later) including a suspension member that may ultimately be removed are also illustrated.

[0018] As shown in FIGS. 1 and 2, the top plate structure 1 is mounted across a pair of support members 10 (10a, 10b), such as the side walls and middle walls of a culvert. The support member 10 includes a shoulder portion 12 for mounting a precast slab 20 on the upper surface and a top portion 14 that extends further upward from the shoulder portion 12. The top plate structure 1 includes a plurality of precast slabs 20 whose end portions in the width direction (X direction in the figure) face each other so as to span the pair of support members 10. In the configuration according to the present embodiment, the plurality of precast slabs 20 are mounted adjacent to each other in the length direction (Y direction in the figure) of the culvert.

[0019] The precast slab 20 may be a concrete member (so-called precast concrete member) prefabricated in a factory or the like, and may be fabricated to include a reinforcing material 27. The reinforcing material 27 is not particularly limited, but may be, for example, a steel material such as an H-shaped steel, a channel steel, or a PC steel material. That is, the precast slab 20 and the reinforcing material 27 may be configured as a so-called half-precast member 40 that is integrally formed.

[0020] In the top plate structure 1 according to the present embodiment, the half-precast member 40 is used as a long member, the half-precast member 40 is mounted across a pair of support members 10 (10a, 10b), and concrete (in-situ concrete portion 50 described later) is placed on the upper part thereof for construction.

[0021] As shown in Fig. 2, when constructing the top plate structure 1, a support 30 is installed so as to span the opposing tops 14, 14 of the support members 10 above the half-precast member 40. The support 30 may be, for example, an H-shaped steel. A plurality of hanging members 33 extending downward are connected to the support 30. As the hanging members 33, various steel materials such as deformed reinforcing bars, separators, PC steel materials, and all-thread bolts may be used.

[0022] The connecting means between the support 30 and the hanging member 33 is arbitrary. For example, the support 30 may be drilled, the upper end of the hanging member 33 may be male-threaded, and the male thread and the nut may be fastened at the connecting portion between the support 30 and the hanging member 33 for connection.

[0023] Also, when the half-precast member 40 is suspended by the support 30, the lower end of the hanging member 33 and the reinforcing member 27 of the half-precast member 40 are connected. The connecting means is arbitrary. For example, the reinforcing member 27 may be drilled, and a nut (not shown) and a male thread may be screwed together through the drilled hole for connection.

[0024] Above the half-precast member 40, a cast-in-place concrete portion 50 where concrete is cast is formed. As shown in Fig. 2, when forming the cast-in-place concrete portion 50, at least a part of the reinforcing member 27 and the hanging member 33 may be embedded inside, and concrete is also cast on the upper part of the shoulder 12. For example, the concrete may be cast so that its upper surface position coincides with the upper end of the top 14 in the height direction.

[0025] As described above, the top plate structure 1 is configured as shown in Figs. 1 and 2. In the top plate structure 1, the support 30 shown in Fig. 2 is used in the construction process, and the half-precast member 40 is suspended. Hereinafter, the method of suspending a long member and construction management, as exemplified by the suspension of the half-precast member 40 by this support 30, will be described.

[0026] <Configuration when suspending a long member> FIG. 3 is a schematic overhead view showing the configuration in a state where a half-precast member 40 as a long member is suspended. In FIG. 3, for the sake of simplicity of illustration, a part of the support member 10 shown in FIGS. 1 and 2 is omitted from the illustration, and the in-situ concrete part 50 is not shown.

[0027] As shown in FIG. 3, the half-precast member 40 as a long member is suspended from the shoring 30 in a state where both ends are mounted on the support member 10. A plurality of suspension members 33 extending downward are connected to the shoring 30, and the lower ends of these suspension members 33 and the reinforcing member 27 of the half-precast member 40 are connected, whereby the suspended half-precast member 40 is suspended. In the present embodiment, the suspension members 33 are connected at five locations on the shoring 30, and the connection with the reinforcing member 27 is also made at five locations.

[0028] The shoring 30 is arranged with both ends supported. The support method is arbitrary. For example, it may be spanned over the support member 10 (the top 14 thereof) as shown in FIG. 2, or may be supported using a support member such as the receiving girder 56 as shown in FIG. 3.

[0029] The half-precast member 40 is mounted across a pair of support members 10 (10a, 10b) in a state of being suspended from the shoring 30. At this time, both end portions 40a, 40b of the half-precast member 40 may be fixed to the support member 10. The fixing means may be a means of being pressed from the shoring 30 via the tension member 53 as on the left side in FIG. 3, or may be a means of being fixed with a fixing fitting 54 as on the right side in FIG. 3. By such fixing means, when the half-precast member 40 is suspended, it is possible to prevent both end portions 40a, 40b from rising due to the action of the rotational moment.

[0030] At the connection points of the support worker 30 with the suspension members 33, a tension adjustment mechanism 60 is provided for each of the plurality of suspension members 33. That is, the tension adjustment mechanism 60 is provided at a plurality of locations in the longitudinal direction of the support worker 30. One end (the upper end in the figure) of the plurality of suspension members 33 is connected to this tension adjustment mechanism 60, and the other end (the lower end in the figure) is connected to a plurality of locations in the longitudinal direction of the half-precast member 40 respectively. As an example, as shown in the figure, five tension adjustment mechanisms 60a to 60e are provided at five locations in the longitudinal direction of the support worker 30, and suspension members 33 (33a to 33e) may be connected to each tension adjustment mechanism 60 (60a to 60e).

[0031] The tension adjustment mechanism 60 (60a to 60e) is connected to the pressure unit 70, and the tension generated in the suspension member 33 (33a to 33e) can be individually controlled by the operation of the pressure unit 70. The tension adjustment mechanism 60 is, for example, a jack including a buffer material, and the pressure unit 70 may be a hydraulic mechanism that controls the jack hydraulically. Further, the pressure unit 70 may have a function as a control unit that performs tension control by each tension adjustment mechanism 60 (60a to 60e).

[0032] <Procedure for suspending a long member by a support worker> Figures 4 to 8 are schematic explanatory diagrams showing an example of the procedure for suspending the half-precast member 40 as a long member via the suspension member 33 by the support worker 30.

[0033] First, as shown in Figure 4, a pair of support members 10 (10a, 10b) are arranged at predetermined positions. The arrangement and spacing of the support members 10 (10a, 10b) are determined according to the structure to be constructed. Then, as shown in Figure 5, the half-precast member 40 including the precast slab 20 and the reinforcing material 27 is mounted across the pair of support members 10 (10a, 10b) and temporarily arranged. Here, both ends 40a, 40b of the half-precast member 40 may be fixed to the support member 10 by fixing means (not shown).

[0034] Next, as shown in FIG. 6, a receiving beam 56 for bridging the support beam 30 above the half - precast member 40 is arranged. The receiving beam 56 is arranged, for example, on the upper parts of a pair of support members 10 (10a, 10b).

[0035] Then, as shown in FIG. 7, the support beam 30 is arranged so as to bridge a pair of support members 10 (10a, 10b). At this time, the support beam 30 may be supported on the receiving beam 56. Further, the support beam 30 is generally horizontally bridged so that the left - right heights are substantially equal in the height direction (Z - axis direction), and is arranged directly above the half - precast member 40 so that its longitudinal direction is parallel to the longitudinal direction of the half - precast member 40. Here, a plurality of hanging members 33 (33a to 33e) extending downward are connected to the support beam 30.

[0036] Then, as shown in FIG. 8, the lower ends of the respective hanging members 33 (33a to 33e) are connected to the half - precast member 40. Thereby, the half - precast member 40 is suspended by the support beam 30 via the hanging members 33 (33a to 33e). In this state, tension adjustment mechanisms 60 (60a to 60e) are attached to the connection points (here, five points) between the support beam 30 and the hanging members 33 (33a to 33e). The tension adjustment mechanisms 60 (60a to 60e) are connected to a pressure unit 70.

[0037] As described above with reference to FIGS. 4 to 8, the half - precast member 40 as a long member is suspended by the support beam 30 via the hanging members 33. Then, in - situ concrete is placed above the half - precast member 40, and a concrete structure (for example, the top - plate structure 1 according to the present embodiment) is constructed.

[0038] <Method for Suspending a Long Member> When the half-precast member 40 as a long member is suspended by the suspension member 33 via the shoring worker 30, for example, the loads applied to the shoring worker 30 and the half-precast member 40 are different at the start of suspension and after the placement of the in-situ concrete. In order to suppress the deflection of the structure (for example, the slab structure 1) after construction as much as possible, it is required to control the deflection deformation in the half-precast member 40. That is, it is required to keep the half-precast member 40 substantially horizontal as much as possible.

[0039] Therefore, the inventors examined the relationship between the load applied to each of the suspension members 33 (33a to 33e) and the tension applied to the suspension members 33 (33a to 33e) when the half-precast member 40 as a long member is suspended by the shoring worker 30 via the suspension member 33.

[0040] As a result of the inventors' intensive studies, the dead load of the half-precast member 40 and the in-situ concrete (for example, the in-situ concrete part 50) placed above it applied to the suspension members 33 (33a to 33e) is arranged so that each suspension member 33 (33a to 33e) bears it equally, and in all periods of the suspension procedure, in all steps using the suspension members 33 (33a to 33e), construction management is carried out so that equal tension is always generated in all the suspension members 33 (33a to 33e).

[0041] FIG. 9 is a schematic explanatory view of the method for suspending a long member according to the present embodiment. As shown in FIG. 9, the total dead load of the half-precast member 40 and the in-situ concrete part 50 is defined as P0, and the dead loads applied to the suspension members 33 (33a to 33e) provided at five locations are defined as P1 to P5. Note that P0 = P1 + P2 + P3 + P4 + P5.

[0042] In the method for suspending a long member according to this embodiment, first, the positional relationship of the suspension members 33 (33a to 33e) arranged and connected to five positions of the support structure 30 is designed such that all the dead loads P1 to P5 applied to each are equal (P1 = P2 = P3 = P4 = P5). This design may be performed, for example, in advance by simulation analysis, experiments, or the like. With the suspension members 33 (33a to 33e) connected to the support structure 30 in the arranged configuration designed in this way, the procedure for suspending the long member is carried out.

[0043] In addition, when the dead load applied as shown in FIG. 9 is dispersed only at five positions, the positional relationship of the suspension members 33 (33a to 33e) arranged and connected to five positions of the support structure 30 may be, for example, a positional relationship that is equally spaced in the longitudinal direction of the support structure 30. Also, when the dead load is dispersed at other positions by support members 10 and receiving girders 56 (not shown here), an analysis may be performed in advance by simulation analysis, experiments, or the like to determine how the load is dispersed, and the positional relationship may be determined based on that.

[0044] By providing tension adjustment mechanisms 60 (60a to 60e) to each of the suspension members 33 (33a to 33e) connected to the support structure 30 based on the design as described above, the tension generated in each suspension member 33 (33a to 33e) is individually adjusted and controlled by a pressure unit 70 (not shown in FIG. 9).

[0045] With the half - precast member 40 as the long member suspended by the support structure 30 via the suspension members 33 (33a to 33e), let the tensions generated in each suspension member 33 (33a to 33e) be T1 to T5. This tension may be measured, for example, by a tension measuring device provided in the tension adjustment mechanism 60 (60a to 60e).

[0046] In the method for suspending a long member according to the present embodiment, in a state where the half-precast member 40 is suspended via the suspension members 33 (33a to 33e) by the support work 30, the tension adjusting mechanisms 60 (60a to 60e) are used to adjust the tensions so that all of the above tensions T1 to T5 are equal (T1 = T2 = T3 = T4 = T5). The tension control to make all of the tensions T1 to T5 equal may be performed by a pressure unit 70 connected to the tension adjusting mechanisms 60 (60a to 60e).

[0047] In the method for suspending a long member according to the present embodiment, by performing the above-described tension control, even in a case where different loads are applied to the suspension members 33 (33a to 33e), such as at the start of suspension or after the placement of in-situ concrete, the construction can be carried out while keeping the half-precast member 40 as a long member substantially horizontal at all times.

[0048] <The effects of the present embodiment> According to the method for suspending a long member according to the present embodiment described above, the construction can be carried out while keeping the half-precast member 40 as a long member substantially horizontal at any timing, such as at the start of suspension or after the placement of in-situ concrete. As a result, the deflection generated in the structure (for example, the top plate structure 1) constructed after the construction is suppressed, and the construction accuracy is improved.

[0049] Further, by keeping the half-precast member 40 in a state without deflection before and after the placement of in-situ concrete, it is possible to prevent residual stress from remaining in the half-precast member after the in-situ concrete has solidified.

[0050] In addition, when suspending a long member, it becomes unnecessary to perform individual torque management at each suspension position, so it is possible to reduce the number of skilled workers, and the workability is improved, such as labor saving and shortening of the construction period.

[0051] As described above, an example of an embodiment of the present invention has been explained, but the present invention is not limited to the illustrated form. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the idea described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

[0052] In addition, the effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the technology according to the present disclosure can exhibit other effects obvious to those skilled in the art from the description of this specification, together with or instead of the above effects.

[0053] For example, in the above embodiment, the top plate structure 1, which is the top plate of a culvert, is illustrated as an example of a structure constructed using the method for suspending a long member according to the present invention, but the target structure is not limited to this. That is, it is applicable to any structure such as the top plate of a drainage treatment facility, the top plate of an underground storage yard, or the top plate of an excavation tunnel, where an elevated bridge is constructed above an existing facility.

[0054] In addition, in the above embodiment, the half-precast member 40 including the precast slab 20 and the reinforcing material 27 as long members and integrally formed thereof is illustrated and described, but the long members are not limited to this. The long member may be any member as long as a plurality of suspension members 33 extending downward from the shoring 30 can be connected. For example, it may be a member composed of a single steel material such as H-shaped steel, channel steel, or PC steel material. Note that the length of the long member varies depending on the structure to be constructed, and may be, for example, a member of 5 m or more.

Industrial Applicability

[0055] The present invention can be applied to a method for suspending a long member.

Explanation of Reference Numerals

[0056] 1... Top plate structure 10... Support member 12... Shoulder 14…Top 20…Precast slab 27…Reinforcing material 30…Scaffolding 33…Suspension material 40…Half-precast member 50…In-situ concrete part 60…Tension adjustment mechanism 70…Pressure unit

Claims

1. A method for suspending a long member by a shoring worker via a plurality of suspension members, comprising: installing the shoring worker above the long member laid horizontally across a pair of support members so as to be parallel to the longitudinal direction of the long member; the shoring worker being provided with a plurality of tension adjustment mechanisms for adjusting the tension generated in the suspension members, each for a plurality of the suspension members in the longitudinal direction; connecting one end of each of the plurality of suspension members to each of the plurality of tension adjustment mechanisms, and connecting the other end to a plurality of locations in the longitudinal direction of the long member; performing tension control so that the tensions generated in the plurality of suspension members are the same, and suspending the long member horizontally.

2. the long member is a half-precast member; when placing cast-in-situ concrete above the half-precast member to construct a cast-in-situ concrete part, tension control is performed so that the tensions of the plurality of suspension members are kept the same when the tensions generated in the plurality of suspension members change.

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