JP4733476B2 - Method for constructing suspended concrete frames - Google Patents

Description

  In the present invention, when a shaft or a foundation structure is constructed by a caisson method by a cast-in-place concrete method, etc., the concrete frame connection to be submerged until reaching a ground having a strength capable of supporting the concrete frame connection body. The present invention relates to a suspension construction method for a concrete frame linking body constructed by a cast-in-place concrete method while suspending a body.

  Conventionally, in general, when a concrete frame connection body (caisson or well) formed by cast-in-place concrete method is submerged from the ground or water to the ground or underwater ground, a base frame is placed around the concrete frame connection to be constructed. And install an underground anchor to support the reaction force of the subsidence of the concrete frame joint and connect it to the base frame, while excavating the ground inside the concrete frame link, the concrete frame link above the base frame Press-fit from below.

  The concrete frame connected body is provided with a blade edge at the lower end, and the blade edge bites into the ground as the ground inside the concrete frame connected body is excavated, and enters the planned ground.

  There are various techniques for sinking a concrete frame connecting body while sequentially adding concrete frames.

  For example, as a technique for sinking a concrete frame connected body in a relatively soft formation, while excavating and discharging the ground at the bottom of the concrete frame connected body using a drilling bucket having a swivel bending arm operated from the ground In addition, there is a technique in which a push-down device is attached to the upper part of a concrete body linking body to sink the concrete body linking body (for example, see Patent Document 1).

  In addition, when the stratum in which the concrete frame connection body is set is a hard stratum, a drilling device for rock excavation is used. For example, a drill casing is inserted into a concrete frame connection body, and drilling blades planted at the lower end of the drill casing and planted on the outer side of the drill casing on the side and bottom of a diameter-expanded wing that is axially mounted within a predetermined angle. There is a technique of performing excavation under the cutting edge of a concrete frame connecting body with the excavating blade provided and sinking while controlling the settlement of the concrete frame connecting body (see, for example, Patent Document 2).

However, these techniques are used when the ground in the subsidence area is in a state where it can support the concrete frame connection body.
Japanese Patent Laid-Open No. 4-64620 Japanese Patent Laid-Open No. 10-317376

  If the upper part of the subsidence area is a soft ground layer or river that cannot support the concrete frame connection body, for example, the concrete frame connection body may be suspended with a suspension wire, etc. It is necessary to hang down and suspend while temporarily supporting the concrete frame connected body until it reaches the ground where it can be supported.

  In order to sequentially add a cast-in-place concrete frame to the upper end of a concrete frame link suspended by a hanging wire as the concrete frame link is suspended in such a subsidence area, for example, at the upper end of an existing concrete frame link Attach a support bracket, etc., lock this support bracket to the support member provided on the ground, suspend and support the existing concrete frame assembly, assemble a reinforcing bar above it, attach the formwork, and place it in this formwork It was necessary to cast cast concrete. In this case, when the suspension load of the concrete frame connection body is increased, there is a problem that the strength of the support bracket and its mounting portion is insufficient, and a strong support member is required.

  SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has an object to provide a technique capable of suspending construction even when a suspended load of a concrete frame assembly increases without requiring a support bracket or a support member provided on the ground. To do.

  The method for suspending a concrete frame assembly according to the present invention that achieves the above object uses two upper and lower suspension frames that can be lifted and lowered independently of each other, and the concrete frame assembly can be suspended with a suspension material. The two suspension frames are alternately stepped upward while being extended, the suspension material is replaced with the two suspension frames, the lower suspension frame is brought close to the upper suspension frame, and the lower suspension frame and Create a space to place cast-in-place concrete between the existing concrete frame connection body, and place the new concrete frame in place on the existing concrete frame connection body in this space, and repeat the process of adding the frame To do.

  Here, the frame connection body refers to a structure formed by vertically adding a frame to be laid, and includes one case.

  The suspension material is a rod-like member that suspends the concrete frame connection body and can be extended upward, and is a member made of, for example, a long bolt, a PC steel material, a Gebinde steel rod, a PC strand, or the like.

  The method for suspending a concrete frame connection body according to the present invention is a technique for sequentially adding and suspending cast-in-place concrete frames, and requires a support bracket for supporting an existing concrete frame connection body, a support member provided on the ground, and the like. Install without having to. The lower suspension frame is connected to the existing concrete frame by changing the suspension material that suspends the concrete frame connection body to the two upper and lower suspension frames that can be moved up and down independently, and alternately moving the two suspension frames upward. A space for placing cast-in-place concrete between the body and the body will be created.

  According to the present invention, when the cast-in-place concrete frame is suspended and suspended while suspending the concrete frame connection body to be laid down until reaching a ground having a strength capable of supporting the concrete frame connection body, In this way, without connecting brackets or supporting members provided on the ground, the concrete frame connected body is hung with a hanging material, and this hanging material is replaced with two hanging frames so that the two hanging frames are alternately turned upward. By stepping up, it was possible to create a space for assembling reinforcing bars, attaching and detaching formwork, and placing cast-in-place concrete, adding cast-in-place concrete frames, and building suspensions. The present invention has an excellent effect, particularly when the mass of the suspended concrete frame assembly is large.

  Embodiments of the present invention will be described below with reference to the drawings.

  The present invention is a technique applied when the upper layer portion of a subsidence area is a soft ground layer or river that cannot support a concrete frame connection body. It is a construction method that is formed by sequentially adding. And it constructs, suspending the concrete frame coupling body which should be laid down with a suspension material until it reaches the ground which has the intensity which can support a concrete frame coupling body.

  Hereinafter, each process of embodiment of the suspension construction method of the concrete frame coupling body of this invention is demonstrated with reference to FIGS. 1-3.

  FIG. 2 is a side view of the state in which the concrete frame connector 10 is suspended in the air.

  As shown in FIG. 2, a concrete frame connector 10 formed by adding concrete frames 11 and 12 is suspended by a first suspension frame 30 suspended by a suspension wire 41 via a suspension material 20 such as a Gebinde steel rod. Suspended in the air. The suspension member 20 is locked to the upper surface of the first suspension frame 30.

  In addition, a second suspension frame 50 suspended by a suspension wire 42 that can be lifted and lowered independently of the first suspension frame 30 is disposed immediately above the first suspension frame 30.

  FIG. 3 is a side view showing a state in which the second suspension frame 50 shown in FIG. 2 is raised.

  As shown in FIG. 3, after the second suspension frame 50 is raised, the suspension member 20 that is locked to the upper surface of the first suspension frame 30 is extended upward, and the extended suspension member 20 is moved to the second portion. The suspension frame 50 is supported on the upper surface of the suspension frame 50. At this time, the load of the concrete frame connector 10 is applied to the second suspension frame 50, and the suspension load of the first suspension frame 30 is released.

  FIG. 1 is a side view of a state in which a cast-in-place concrete frame 80 is placed by raising the first suspension frame 30 shown in FIG.

  As shown in FIG. 1, after the first suspension frame 30 is raised and brought close to the second suspension frame 50, the suspension member 20 is locked to the upper surface of the first suspension frame 30, and a concrete frame is obtained. The load of the coupling body 10 is supported by the first suspension frame 30 and the suspension load of the second suspension frame 50 is released.

  By passing through the process demonstrated above, the space which casts a cast-in-place concrete frame between the 1st suspension frame 30 and the existing concrete frame coupling body 10 is created.

  The rebar 60 is assembled in the space created in this way, the formwork 70 is attached, the cast-in-place concrete frame 80 is placed and cured in the formwork 70, and the formwork 70 is removed. A cast-in-place concrete frame is added to the upper end of the concrete frame connector 10.

  Hereafter, each process of the suspension construction method of a concrete frame coupling body demonstrated with reference to FIGS. 1-3 is repeated.

  Next, each process of another embodiment of the method for constructing a suspended suspended concrete body of the present invention will be described with reference to FIGS. In the embodiment described below, attention is paid to differences from the above-described embodiment, and the same elements are denoted by the same reference numerals and description thereof is omitted.

  FIG. 4 is a side view of the state in which the concrete frame connector 10 is suspended in the air.

  As shown in FIG. 4, the concrete frame connector 10 is suspended in the air via a suspension material 20 such as a Gebinde steel rod by a second suspension frame 50 suspended by a suspension wire 42. The suspension member 20 is locked to the upper surface of the second suspension frame 50.

  Further, immediately below the second suspension frame 50, a first suspension frame 30 suspended by a suspension wire 41 that can be moved up and down independently of the second suspension frame 50 is disposed.

  FIG. 5 is a side view showing a state in which the suspension member 20 shown in FIG. 4 is extended upward.

  As shown in FIG. 5, the suspension member 20 locked to the upper surface of the second suspension frame 50 is extended upward.

  FIG. 6 is a side view of the state in which the suspension member 20 is replaced with the upper surface of the first suspension frame 30.

  As shown in FIG. 6, the suspension member 20 is engaged with and supported by the upper surface of the first suspension frame 30. At this time, the load of the concrete frame connector 10 is applied to the first suspension frame 30 and the suspension load of the second suspension frame 50 is released.

  FIG. 7 is a side view showing a state where the second suspension frame 50 shown in FIG. 6 is raised.

  As shown in FIG. 7, after raising the second suspension frame 50, the suspension member 20 retained on the upper surface of the first suspension frame 30 is retained on the upper surface of the second suspension frame 50. Support. At this time, the load of the concrete frame connector 10 is applied to the second suspension frame 50, and the suspension load of the first suspension frame 30 is released.

  FIG. 8 is a side view showing a state in which the cast-in-place concrete frame 80 is placed by raising the first suspension frame 30 shown in FIG.

  As shown in FIG. 8, the cast-in-place concrete is placed between the first suspension frame 30 and the existing concrete frame connector 10 by raising the first suspension frame 30 and bringing it close to the second suspension frame 50. A space is created to place the frame.

  Hereinafter, each process of the suspension construction method of a concrete frame coupling body described with reference to FIGS. 4 to 8 is repeated.

  According to the method for constructing a suspended concrete frame assembly according to each embodiment described above, a support bracket for supporting an existing concrete frame coupled body, a support member provided on the ground, or the like is not required, and the suspension is particularly suspended. When the mass of the concrete frame assembly is large, the effect is excellent. For this reason, a cast-in-place concrete frame can be added to the upper end of the concrete frame connection body in sequence, and can be easily suspended.

  In the above-described embodiment, an example in which the frame connection body of the present invention is formed by vertically adding the frame bodies to be installed has been described. Including.

It is a side view of the state which raises the 1st suspension frame 30 shown in FIG. 3, and casts the cast-in-place concrete frame 80. It is a side view of the state which suspended the concrete frame coupling body 10 in the air. It is a side view of the state which raised the 2nd suspension frame 50 shown in FIG. It is a side view of the state which suspended the concrete frame coupling body 10 in the air. It is a side view of the state which extended upwardly the hanging material 20 shown in FIG. 3 is a side view of a state in which the suspension member 20 is replaced with the upper surface of the first suspension frame 30. FIG. It is a side view of the state which raised the 2nd suspension frame 50 shown in FIG. It is a side view of the state which raises the 1st suspension frame 30 shown in FIG. 7, and casts the cast-in-place concrete frame 80. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Concrete frame connection body 11,12 Concrete frame 20 Suspension material 30 1st suspension frame 41,42 Suspension wire 50 2nd suspension frame 60 Rebar 70 Formwork 80 Cast-in-place concrete frame

Claims (1)

  Using the two upper and lower suspension frames that can be raised and lowered independently and can suspend the concrete frame connection body with the suspension material, while extending the suspension material upward, the two suspension frames are alternately stepped upward, The suspension material is replaced with the two suspension frames, and the lower suspension frame is brought close to the upper suspension frame to create a space for placing cast-in-place concrete between the lower suspension frame and the existing concrete frame connector. In this space, a method for suspending construction of a concrete frame connection body is characterized by repeating a step of placing a new concrete frame on an existing concrete frame connection body and adding the frame.

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