JP2007211547A - Spacer for placing joint part and reverse placement construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably integrate a new concrete member with existing concrete in a reverse placement construction method. <P>SOLUTION: When placing concrete in the reverse placement construction method, a spacer 10 is interposed on the existing concrete member for securing a predetermined space thereon purposely, and a filler is injected by pressure for completely closing the space at the end. The spacer 10 for it includes a spacer body 11 of a flat frame shape, a net 16 or ventilation material of a perforated plate attached to its bottom, an injection hose 21 for injecting the filler into the spacer body and an ejection hose 22 for discharging air from the spacer body. Furthermore, the injection hose and the ejection hose respectively are composed of a net material which can exude the filler. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spacer for a joint portion used when a new concrete member is integrally handed over to the lower surface side of an existing concrete member by a reverse casting method, and a reverse casting method using the spacer.

As is well known, in the reverse casting method, a new concrete member (concrete to be constructed) is handed over to the lower surface side of an existing concrete member (concrete that has already been constructed). In the case of jointing, air may remain in the jointed part and voids may be formed. In that case, the integrity of the two concrete members cannot be secured, and the waterstop and structure there It is inevitable that the reliability of the entire product will be significantly reduced.
Therefore, in the conventional reverse driving method, it is necessary to visually observe the joint portion after construction, and when there is a gap, it is necessary to perform a repair work to fill the gap by filling with a filler such as an epoxy resin. .

Moreover, it is also widely carried out on the premise that the filler is injected after the construction. For example, Patent Document 1 discloses a hose for filling the filler with a filler later, There is a proposal for a gap filling method in which a hose for exhausting air from the joint portion is provided in advance.
JP 10-196112 A

  However, repairing by visually observing the joint part not only requires a lot of labor and expense, but it is not always necessary to reliably and completely repair the gap generated deep inside the joint part. It's not easy.

  In addition, the gap filling method disclosed in Patent Document 1 is preliminarily charged with a partitioning material and a hose for exhausting air at the stage of constructing the preceding concrete on the assumption that the preceding concrete and the following concrete are constructed sequentially. Since it is used at the stage of construction of the following concrete, it can be applied in a limited manner in the case of the reverse driving method premised on such a series of work processes. It cannot be applied. For example, it cannot be applied to the case where concrete is struck repeatedly by the back-coating method for the purpose of reinforcing or renovating existing structures. In addition, if the partitioning material or the hose is simply embedded in the preceding concrete as in Patent Document 1, there is a concern that the filling property of the concrete with respect to those surroundings may remain, and the reliability in that respect is not necessarily sufficient. .

  In view of the above circumstances, an object of the present invention is to provide an effective and appropriate method for solving the above-described problem in the reverse driving method.

  The invention described in claim 1 is a spacer for a joint portion used for joining a new concrete member to the lower surface side of an existing concrete member by a reverse casting method and integrating both concrete members, Is a flat frame shape that is open and is attached to the lower surface of an existing concrete member, a ventilation member attached to the bottom surface of the spacer body, and a filler for injecting the filler inside the spacer body An injection hose and a discharge hose for discharging air from the inside of the spacer body, wherein the ventilation material is made of a net or a perforated plate through which concrete hardly passes and air passes, The discharge hose is characterized in that a net-like material capable of exuding the filler itself is formed in a tubular shape.

  According to a second aspect of the present invention, in the spacer according to the first aspect of the invention, the bottom of the spacer main body is provided with a lattice-like support member that supports the ventilation material from the upper surface side.

  The invention described in claim 3 is a reverse driving method for integrally transferring a new concrete member to the lower surface side of an existing concrete member using the spacer according to claim 1 or 2, wherein the new concrete member is Prior to the concrete placement for forming, the spacer is attached to the lower surface of the existing concrete member, and during the concrete placement, air is vented through the ventilation material, the injection hose and the discharge hose of the spacer, and the ventilation material is used. Preventing the inflow of concrete into the spacer body to secure a space in which the concrete is not filled in the spacer body, and then pressurizing and injecting filler into the space in the spacer body through the injection hose and passing through the discharge hose Vent air from inside, and at the same time around the ventilation material, injection hose, and discharge hose. By exude filler, the spacer body, injection hose, characterized by filling the filling material within and around the drain hose.

  According to the spacer of the present invention and the reverse casting method using the spacer, a gap corresponding to the height of the spacer body is secured between the existing concrete member and the new concrete member at the time of concrete placement. In this case, the gap can be completely closed by pressurizing and filling the filler with the filler. Moreover, the air in the mold is exhausted through the spacer when placing concrete, and the injection hose, exhaust hose, net attached to the bottom of the spacer body, etc. Due to the exudation from the air-permeable material, the surroundings can also be filled with the filler, so that complete joining is possible and the two concrete members can be structurally and reliably integrated.

Embodiments of the present invention will be described below. The following embodiment is an example in the case where the present invention is applied to a seismic isolation method for renovating an existing building to a seismic isolation building, and FIG. 1 shows a basic process of the seismic isolation method. .
As shown in (a), from the state before renovation composed of the existing pile 1 and the existing foundation 2, the existing ground 2 is supported by the existing pile 1 as shown in (b). The pile head of the existing pile 1 is exposed by root cutting, and as shown in (c), the new foundation 3 is formed integrally with the pile head, and the pile head protruding from the top is excised to remove the existing pile. 1 and the existing foundation 2 are separated, and then, as shown in (d), a seismic isolation device 4 such as laminated rubber is installed on the new foundation 3 to support the entire existing building.

  In this case, it is necessary to install the lower foundation 5 integrally on the upper surface of the new foundation 3 at the bottom of the seismic isolation device 4 and to install the upper foundation 6 integrally on the lower surface of the existing foundation 2 above the seismic isolation device 4. is there. And the lower foundation 5 can be integrated with the new foundation 3 without any structural problems by a normal construction method, but the construction of the upper foundation 6 should be carried out on the lower surface side of the existing foundation 2 by the reverse driving method. Therefore, as described above, there is a concern that a normal reverse driving method may cause a gap between them and cannot be reliably integrated structurally.

Therefore, in the present embodiment, the construction of the upper foundation 6 is mainly performed by the construction shown in FIG. 3 using the spacer 10 shown in FIG.
That is, in the present embodiment, the upper base to be constructed is used by using the spacer 10 mainly composed of a flat square frame spacer main body 11 and mounting the spacer 10 on the lower surface of the existing foundation 2 when constructing the upper foundation 6. The upper base 6 is formed in a state where a gap corresponding to the height dimension of the spacer main body 11 is intentionally secured between the existing base 2 and the existing base 2, and finally the gap is formed by filling the spacer main body 11 with a filler. I try to close it completely.

The spacer main body 11 is formed by assembling a reinforcing bar 12 in a square frame shape and welding a long strip steel plate 13 (flat bar) to the upper part of the spacer main body 11, and its upper surface is opened as it is. A lattice-like support member 15 in which reinforcing bars 14 are assembled vertically and horizontally is provided on the bottom surface, and a net 16 as a ventilation material is attached to the bottom surface thereof. The net 16 naturally has air permeability, but the net 16 is a fine mesh (for example, about 2.5 mm) that can substantially prevent the concrete placed when the upper foundation 6 is constructed. The wire mesh is used.
The support member 15 is for preventing the bending of the net 16 at the time of placing concrete, and the structure thereof is appropriate. However, the support member 15 is supported when the net 16 itself has sufficient strength and is difficult to bend. The member 15 can be omitted. On the other hand, if necessary, if a short reinforcing bar or the like is used as a support column 17 to stand up at the important point of the support member 15 as shown in the figure, the net 16 and the support member 15 bend upward when placing concrete. It is possible to surely prevent the leakage.

  In addition, a part of the strip steel plate 13 is cut off at the four corners of the spacer body 11, and two injection hoses 21 and two discharge hoses 22 are connected to each of them. The injection hose 21 is for injecting a filler such as non-shrink mortar or epoxy resin into the spacer body 11 under pressure, and the discharge hose 22 is for discharging air from the spacer body 11 at that time. However, as the injection hose 21 and the discharge hose 22, so-called net hoses are used in which a net-like material that can exude a filler is formed in a tubular shape.

The specific specification of the spacer 10 may be appropriately set in consideration of the size of the upper foundation 6 to be constructed, the type of filler used, and the like. For example, for example, the diameter of the seismic isolation device 4 Is 750 mm, the upper base 6 is a square shape with a side of 2000 mm, and an application example when using a non-shrink mortar as a filler is as follows. What is necessary is just about 40 mm (reinforcing bar 12 with 9 mmφ + band steel plate 13 with a height of 30 mm). The reinforcing bar 14 as the support member 15 may be 9 mmφ or 6 mmφ, and the net 16 is preferably a 2.5 mm mesh wire net as described above. As the injection hose 21 and the discharge hose 22, for example, a fiber made of polypropylene resin formed into a tubular shape by hollow knitting can be suitably employed, and the diameter thereof is preferably about 25 mmφ.
When an epoxy resin is used as the filler, the height of the spacer body 11 may be about 20 mm (9 mmφ rebar 12 + 10 mm high steel strip 13), and the diameters of the injection hose 21 and the discharge hose 22 are also about 10 mm. Good.

A specific work procedure for constructing the upper foundation 6 using the spacer 10 is shown in FIG. 3, after the lower foundation 5 is constructed from the state of FIG. 1 (c) and the seismic isolation device 4 is installed on the upper part, the upper foundation 6 is reversed between the seismic isolation device 4 and the existing foundation 2. The procedure for construction is shown below. First, as shown in (a), the spacer 10 is mounted on the lower surface of the existing foundation 2 and fixed by appropriate means. At that time, the injection hose 21 and the discharge hose 22 are pulled out to the side by predetermined dimensions.
Then, a formwork (not shown) is assembled and concrete is placed therein. At the final stage of placing, the air in the mold is pushed out into the spacer body 11 through the net 16 as a ventilation member attached to the bottom surface of the spacer body 11, and further, as shown by the arrow, the spacer body 11 It is discharged from the inside through the injection hose 21 and the discharge hose 22.

When the concrete placement is completed and the upper foundation 6 is formed as shown in (b), the spacer 10 is interposed between the upper foundation 6 and the existing foundation 2 in an embedded state. Since the placed concrete cannot pass through the net 16 attached to the bottom surface of the spacer main body 11, the inside of the spacer main body 11 is left as a void not filled with concrete.
Therefore, as shown in the figure, the filler is pressurized and injected into the spacer body 11 through the injection hose 21. As a result, air is naturally discharged from the spacer body 11 through the discharge hose 22, so that the filler is pressurized and injected until the filler flows out from the discharge hose 22.
The injection method and injection pressure at that time may be set as appropriate, but when the filler is non-shrink mortar, it may be set to an injection pressure of about 0.3 Mpa using a general-purpose grout pump.

  If the filler is hardened after a predetermined curing period has elapsed and the excess portions of the injection hose 21 and the discharge hose 22 are removed, the upper base is left in the state where the entire spacer 10 is embedded as shown in FIG. 6 is completed.

  As described above, the spacer 10 is interposed in the joint portion, and the filler is pressurized and injected into the joint portion according to the above-described procedure. It is effectively discharged and no air pool is generated. Finally, the filling material is completely filled not only in the spacer body 11 but also in the injection hose 21 and the discharge hose 22 so that the entire spacer 10 is made of concrete. Since it is completely buried therein, there is no room for leaving a gap between the existing foundation 2 and the upper foundation 6, and they can be integrated structurally and reliably.

  In addition, since the filling hose 21 and the discharge hose 22 are made of a material from which the filler can bleed out, and the bottom surface of the spacer body 11 is constituted by the net 16, there is a slight amount of air around them when placing concrete. Even if there is a reservoir, when the filler is pressurized and injected, the filler naturally oozes out from the injection hose 21 and the discharge hose 22 itself into the surroundings, and from the inside of the spacer body 11 through the net 16. Since it also oozes out to the bottom surface side, the filler is naturally filled in such an air reservoir, and it is possible to completely close the gap also in this respect.

  Further, the spacer 10 can be manufactured easily and inexpensively by using only general-purpose construction materials such as rebars 12 and 14, the strip steel plate 13, and a wire mesh as the net 16. What is widely used in construction can be diverted, and general commercial products such as non-shrink mortar and epoxy resin can be used as the filler, so the cost increase by adopting this construction method is minimal, It is extremely effective as a reverse driving method that requires a high degree of structural integration.

The embodiment of the present invention has been described above. However, the above embodiment is merely a preferred example, and the present invention is not limited to the above embodiment, and appropriate design changes such as those listed below are possible. Application is possible.
In the above embodiment, the net 16 such as a wire net is used as a ventilation member attached to the bottom surface of the spacer body 11, but it is also conceivable to use a perforated plate having a desired aperture ratio instead of the net.
In the above embodiment, two injection hoses 21 and two discharge hoses 22 are provided. However, at least a pair of them is sufficient, and the number may be appropriately increased or decreased depending on the size and shape of the spacer body 11. However, in any case, in order to reliably fill the entire interior of the spacer body 11, the positional relationship between the fillers should be set appropriately so as not to cause a short circuit.
Furthermore, although the said embodiment is an example applied to construction of the upper foundation 6 of the seismic isolation apparatus 4 in the case of the seismic isolation method of the existing building, this invention is not restricted to this, A new concrete member is used for the existing concrete member. On the other hand, it is needless to say that the present invention can be applied widely in general when it is necessary to integrate the structure reliably.

It is a figure which shows the basic process of the seismic isolation construction method to which the reverse driving method which is embodiment of this invention is applied. It is a figure which shows the spacer which is embodiment of this invention. It is a figure which shows the procedure of the reverse driving method which is embodiment of this invention.

Explanation of symbols

1 Existing pile 2 Existing foundation (existing concrete member)
3 New foundations 4 Seismic isolation devices 5 Lower foundations 6 Upper foundations (new concrete members)
DESCRIPTION OF SYMBOLS 10 Spacer 11 Spacer main body 12 Reinforcement 13 Band steel plate 14 Reinforcement 15 Support member 16 Net (ventilation material)
17 Strut 21 Injection hose 22 Discharge hose

Claims (3)

A spacer for a joint portion used to integrate a new concrete member on the lower surface side of an existing concrete member by a reverse casting method to integrate both concrete members,
In order to inject a filler into the inside of the spacer body, a spacer body that has a flat frame shape with an open upper surface and is attached to the lower surface of an existing concrete member, a ventilation material attached to the bottom surface of the spacer body And an exhaust hose for exhausting air from the inside of the spacer body,
The air-permeable material is made of a net or a perforated plate through which concrete is difficult to pass and air is allowed to pass through,
The injection hose and the discharge hose are formed by forming a net-like material that can exude a filler material into a tubular shape. The spacer according to claim 1,
A spacer for a joining portion, characterized in that a lattice-like support member for supporting a ventilation material from its upper surface side is provided at the bottom of the spacer body. A reverse casting method for integrally casting a new concrete member on the lower surface side of an existing concrete member using the spacer according to claim 1,
Prior to placing concrete to form a new concrete member, the spacer is attached to the lower surface of the existing concrete member,
When casting concrete, air is vented through the spacer's ventilation material, injection hose, and discharge hose, and the ventilation material prevents the flow of concrete into the spacer body to create a gap that is not filled with concrete in the spacer body. Secure,
After that, air is vented from the spacer body through the discharge hose while injecting the filler into the space in the spacer body through the injection hose, and at the same time, the filler is leached around the ventilation material, injection hose, and discharge hose. A reverse hammering method characterized in that a filler is filled in and around the spacer main body, the injection hose, and the discharge hose.

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