JP2011032658A - Apparatus for cooling placed concrete of bridge pier of composite steel pipe-concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce loads of introduction and maintenance of equipment for cooling placed concrete. <P>SOLUTION: This apparatus 1 for cooling the placed concrete includes a blower 2 and a blast duct 3; and the blower 2 is mounted on a lifting reaction base 7 which is laid across a top portion of a hollow steel pipe 5 constituting a bridge pier 4 of a composite steel pipe-concrete structure. Each of upper ends of the blast ducts 3 is connected to an exhaust port of the blower 2. Thus, the upper end of the blast duct 3 can be connected to the blower 2 in such a manner as to communicate with it. Each of the blast ducts 3 is arranged in the hollow steel pipe so as to communicate with the inside of the hollow steel pipe 5 via its lower end. Specifications of the blower 2 are properly determined so that the blower 2 can supply air downward by feeding the air into the blast duct from the upper end of the blast duct 3, discharge the air from a lower end of the blast duct 3, and supply the air as cooled air into the hollow steel pipe 5. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cooling apparatus for cast concrete applied to concrete work among construction works of steel pipe / concrete composite structure piers.

  When constructing piers, in ordinary reinforced concrete structures (hereinafter referred to as RC structures), the higher the height, the more time and labor it takes to place the bars and assemble and disassemble the formwork. In many cases, a steel pipe / concrete composite structure is adopted.

  In constructing such a steel pipe / concrete composite structure, first, the steel pipe is erected in advance, and then the rebar is assembled and the PC strand is wound around the steel pipe, and the formwork is installed. Concrete is placed between the formwork and the steel pipe.

  According to such a steel pipe / concrete composite structure, it is possible to perform rapid construction and to improve the earthquake resistance by the steel pipe.

  On the other hand, if the cross section of the member on which the concrete is placed is large, the concrete temperature rises due to the heat of hydration of the cement accumulated near the center, and the temperature distribution in the cross section is unsatisfactory during the rise process or the subsequent cooling process. It becomes uniform and so-called temperature cracks occur.

  Such temperature cracks can be prevented by cooling with pipe cooling or pre-cooling, or by using low heat-generating concrete, but temperature cracks can also be achieved by taking appropriate measures in concrete construction of steel pipe / concrete composite piers. It is necessary to prevent this beforehand.

Japanese Patent No. 2591422

  Here, in concrete construction of steel pipe / concrete composite structure piers, a method of cooling the cast concrete and preventing its temperature cracks by sprinkling water in the hollow steel pipes erected in advance has been adopted. .

  However, when sprinkling water into the hollow steel pipe, water for sprinkling must be pumped to the top of the steel pipe, and the higher the pier height, the longer the pipe length and the higher the pump height is required. As a result, there is a problem that the burden on facilities is large.

  In addition, for the above-mentioned water pipes and pumps, appropriate maintenance and inspection are required at any time. However, since the water pipes extend in the vertical direction, the maintenance and inspection work tends to be delayed. As a result, the water pipe is ruptured due to the loosening and wear of the bolts, and the concrete work is also interrupted.

  The present invention has been made in consideration of the above-described circumstances, and cooling of cast concrete in a steel pipe / concrete composite structure pier capable of reducing the burden of introducing and maintaining facilities for cooling the cast concrete. An object is to provide an apparatus.

  In order to achieve the above object, the cooling device for cast concrete in the steel pipe-concrete composite structure pier according to the present invention has a blower and a steel pipe connected to the blower at the upper end and connected to the blower via the lower end as described in claim 1. A blower duct disposed in the hollow steel pipe so as to communicate with the hollow steel pipe standing as a steel pipe constituting the concrete composite structure pier, and the blower from the upper end of the blower duct It is configured to send air into the air duct and feed it downward, and discharge the air from the lower end of the air duct to supply it to the inside of the hollow steel pipe, which is supplied to the inside of the hollow steel pipe. The air is adapted to cool the fresh concrete placed around the hollow steel pipe to form a concrete frame constituting the pier. It is.

  Moreover, the cooling device for cast concrete in the steel pipe / concrete composite structure pier according to the present invention is such that the lower end of the air duct is positioned near the bottom of the hollow steel pipe.

  Moreover, the cooling device for cast concrete in the steel pipe / concrete composite structure pier according to the present invention forms two openings in the bottom mold that vertically partitions the interior of the hollow steel pipe in the vicinity of the top of the hollow steel pipe, One of the two openings is an air supply opening through which the air duct is installed, and the other is an exhaust opening.

  Moreover, the cooling apparatus for cast concrete in the steel pipe-concrete composite structure pier according to the present invention includes a joint that is provided through the air duct through the air supply opening, an upper connection end of the joint, and the blower. The upper duct main body is connected to the lower duct connecting body and the lower duct main body is connected to the lower connection end of the joint and extends downward, and the joint is locked to the air supply opening.

  The cooling apparatus for cast concrete in a steel pipe / concrete composite structure pier according to the present invention is applied to concrete work when constructing a steel pipe / concrete composite structure pier. After the hollow steel pipe is erected as the steel pipe constituting the pier, first, a blower duct is installed in the hollow steel pipe, and the blower duct is connected to the blower at its upper end.

  A ventilation duct is arrange | positioned in this hollow steel pipe so that it may connect with the inside of a hollow steel pipe via a lower end.

  After the hollow steel pipe is erected in advance, rebar assembly and PC strand winding are performed around the hollow steel pipe as necessary, and the formwork is built so as to surround them. The concrete frame is built around the hollow steel pipe by performing the work of placing the concrete on the inside from the bottom to the top, but with the concrete placement, the blower described above is driven and the air duct The air is fed into the internal space from the upper end of the pipe, and the air is sent downward, discharged from the lower end of the blower duct, and supplied into the hollow steel pipe.

  If it does in this way, the air supplied into the inside of a hollow steel pipe will act as cooling air which cools the fresh concrete cast around it via the pipe wall of the hollow steel pipe. In addition, since the cooled air is warmed by the heat absorption from the fresh concrete, combined with the discharge pressure from the air duct, it rises in the hollow steel pipe, and from the top of the hollow steel pipe to the atmosphere Naturally exhausted.

  As described above, the fresh concrete placed around the hollow steel pipe is cured as a concrete skeleton by a hydration reaction while temperature cracking is suppressed by the air cooling action by the air supplied into the hollow steel pipe.

  The present invention can be applied not only when a single hollow steel pipe is installed, but also when a plurality of hollow steel pipes are installed. In the case of a plurality of installations, the air duct may be arranged only in one hollow steel pipe. However, it may be installed in an arbitrarily selected hollow steel pipe.

  Further, when a plurality of air ducts are installed, a fan may be provided for each air duct, or a fan capable of concentrated air flow is installed and connected to each air duct in a form branched from the air fan. It may be.

  Although the air duct of the present invention is mainly assumed to be arranged straight inside a vertically erected hollow steel pipe, it does not necessarily require a strict vertical arrangement and is fed from the upper end. As long as the air can be discharged from the lower end, it can be arranged in an arbitrary form, and includes an inclined or spiral arrangement form.

  The blower appropriately determines its specifications so that the air sent into the blower duct is smoothly discharged from the lower end of the blower duct. Moreover, it is desirable that the blower be installed not on the inside of the hollow steel pipe but on the outside of the hollow steel pipe, for example, just above the top of the hollow steel pipe so that fresh air is efficiently fed into the air duct.

  As long as the air sent from the upper end of the air duct is discharged at the lower end and the discharged air can act as cooling air for cooling fresh concrete placed around the hollow steel pipe, the upper end height relative to the hollow steel pipe is high. How to set the height is arbitrary, and the upper end height of the hollow steel pipe top is not restricted, but when the blower is installed directly above the top of the hollow steel pipe, Accordingly, the upper end may be positioned directly above the hollow steel pipe.

  Similarly, how to set the installation height of the lower end with respect to the hollow steel pipe is arbitrary, but if the lower end of the air duct is positioned near the bottom of the hollow steel pipe, the retention of air below the hollow steel pipe is obviated. It is possible to improve the cooling efficiency and reduce the load on the blower.

  The method of supporting the blower or the air duct is arbitrary. For example, it is fixed to the upper edge of the hollow steel pipe wall through an appropriate jig or suspended from the upper edge of the hollow pipe, or lifted to the top of the hollow steel pipe. A method is possible in which a heavy duty reaction force frame is bridged and a blower is attached to the lifting reaction force frame, and the upper end of the blower duct is connected to the discharge port of the blower.

  When a bottom mold that divides the inside of the hollow steel pipe up and down in the vicinity of the top of the hollow steel pipe is provided in the hollow steel pipe, two openings are formed in the bottom mold, and one of the two openings is The air supply opening through which the air duct is installed can be used as the exhaust opening.

  In this configuration, the integrally formed air duct may be inserted into the air supply opening, but instead, the air duct is inserted through the air supply opening, and the joint. The upper duct body that connects the upper connection end of the fan and the blower, and the lower duct body that is connected to the lower connection end of the joint and extends downward, and the above-described joint is locked to the air supply opening. It can be configured.

  According to such a configuration, the weight of the lower duct body can be received by the bottom mold, and the load applied to the blower can be greatly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a layout view of a placing concrete cooling device 1 in a steel pipe / concrete composite structure pier according to the present embodiment, where (a) is a front view and (b) is an arrow view seen from the direction of the line AA. It is detail drawing in the top part vicinity of the hollow steel pipe 5, (a) is a longitudinal cross-sectional view, (b) is sectional drawing along the BB line. Explanatory drawing which showed the effect | action of the cooling device 1 of the placement concrete which concerns on this embodiment.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a concrete cooling apparatus for placing concrete in a steel pipe / concrete composite structure pier according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is an overall view showing a cooling apparatus 1 for cast concrete in a steel pipe / concrete composite structure pier according to this embodiment. As can be seen from FIG. 1, the concrete cooling device 1 according to this embodiment includes a blower 2 and a blower duct 3.

  Here, the concrete cooling device 1 according to the present embodiment is applied to concrete work when the steel pipe / concrete composite structure pier 4 is constructed, and the steel pipe / concrete composite structure pier 4 is arranged in a plane. Is composed of a total of six hollow steel pipes 5 erected so as to form 2 rows × 3 rows and a concrete frame 6 formed so as to surround the periphery thereof.

  On the top of the hollow steel pipe 5, a lifting reaction force frame 7 for lifting a movable mold (not shown) is bridged, and the blower 2 is attached to the lifting reaction force frame. The lifting force reaction stand 7 may be configured by appropriately combining steel materials such as H-shaped steel.

  The blower 2 is provided for each hollow steel pipe 5, and the blower duct 3 is connected to the blower 2 at its upper end by connecting the upper end of the blower duct 3 to the discharge port of the blower.

  The air duct 3 is disposed in the hollow steel pipe so as to communicate with the inside of the hollow steel pipe 5 through the lower end thereof. In the present embodiment, the material shaft of the hollow steel pipe 5 erected vertically It is suspended vertically downward from the blower 2 so as to be parallel.

  The lower end of the air duct 3 is positioned near the bottom of the hollow steel pipe 5 so as to prevent air from staying below the hollow steel pipe.

  The blower 2 sends air into the blower duct from the upper end of the blower duct 3 and feeds it downward, and discharges the air from the lower end of the blower duct 3 so that it can be supplied to the inside of the hollow steel pipe 5. The specifications are determined as appropriate.

  In the vicinity of the top of the hollow steel pipe 5, as can be seen in FIG. 2, a bottom mold 21 is provided to partition the interior of the hollow steel pipe 5 up and down, and by filling the space above the bottom mold with concrete, The steel pipe / concrete composite structure bridge pier 4 is connected to the top portion of the bridge superstructure (not shown). The bottom mold 21 is penetrated by two openings, that is, the air duct 3. An air supply opening 22 and an exhaust opening 23 for moving the air in the hollow steel pipe 5 upward are formed.

  On the other hand, the air duct 3 is connected to the discharge port of the blower 2 and has an upper duct body 24 having an outer diameter set to, for example, about 230 mm according to the diameter of the discharge port, and is necessary and sufficient for air feeding, for example. The lower duct body 26 having an outer diameter of about 190 mm and a joint 25 interconnecting the lower end of the upper duct body 24 and the upper end of the lower duct body 26 are formed on the bottom mold 21. In this configuration, the weight of the lower duct body 26 is supported by the bottom mold 21.

  That is, the joint 25 serves to interconnect the upper duct body 24 and the lower duct body 26 having different diameters and to suspend the lower duct body 26 by the bottom mold 21.

  In order to apply the concrete cooling device 1 according to the present embodiment to the concrete work of the steel pipe / concrete composite structure pier 4, after the hollow steel pipe 5 is erected as the steel pipe constituting the steel pipe / concrete composite structure pier 4 First, the lifting reaction force frame 7 is placed over the top of the hollow steel pipe, and then the blower 2 is attached to the lifting reaction force frame. The blower 2 is installed for each hollow steel pipe in accordance with the standing position of the hollow steel pipe 5.

  Next, by connecting the upper end of the blower duct 3 to the discharge port of the blower 2, the blower duct is connected to the blower 2, and the duct interior space is connected to the hollow steel pipe 5 through the lower end of the blower duct 3. Each hollow steel pipe is suspended so as to communicate with the inside.

  Here, after the hollow steel pipe 5 is erected in advance, the formwork is built so as to surround the hollow steel pipe and surround the hollow steel pipe as necessary while surrounding the steel bars. Then, the concrete frame 6 is sequentially built around the hollow steel pipe 5 by performing the work of placing the concrete inside the formwork from below to above (see FIG. 1). Accordingly, the blower 2 described above is driven, and air is sent into the internal space from the upper end of the blower duct 3 as shown in FIG. 3, and the air is sent downward and discharged from the lower end 31 of the blower duct 3. This is supplied to the inside 32 of the hollow steel pipe 5.

  If it does in this way, the air supplied to the inside 32 of the hollow steel pipe 5 will act as cooling air which cools the fresh concrete 33 cast around it through the pipe wall of the hollow steel pipe.

  Incidentally, the fresh concrete 33 has a temperature exceeding 40 ° C. to 50 ° C. depending on the size of the cross section of the member and the kind of cement, and can be sufficiently cooled even at an outside air temperature of about 25 ° C.

  Since the air that has finished cooling is warmed by the heat absorption from the fresh concrete 33, in combination with the discharge pressure from the blower duct 3, the air rises in the hollow steel pipe 5 and enters the atmosphere from the top of the hollow steel pipe. And naturally exhausted.

  When the concrete work is completed, the lifting reaction force mount 7, the blower 2 and the blow duct 3 are removed, and the air supply opening 22 and the exhaust opening 23 formed in the bottom mold 21 are closed, and the bridge superstructure Preparing for connection work.

  As described above, according to the cast concrete cooling device 1 in the steel pipe / concrete composite structure bridge pier according to the present embodiment, the fresh cast around the hollow steel pipe 5 by the air supplied into the hollow steel pipe 5. The concrete 33 can be air-cooled, and thus the fresh concrete 33 is cured as a concrete skeleton by a hydration reaction while temperature cracking is suppressed.

  Moreover, according to the cooling apparatus 1 of the placement concrete which concerns on this embodiment, the site | part which requires a maintenance is generally restricted to the air blower 2 unlike the conventional water cooling system. Therefore, not only the equipment installation burden but also the maintenance burden is greatly reduced, which contributes to shortening the construction period.

  Moreover, according to the cooling apparatus 1 of the cast concrete which concerns on this embodiment, since the lower end of the ventilation duct 3 was positioned near the bottom part of the hollow steel pipe 5, the retention of the air below the hollow steel pipe 5 is prevented beforehand, It becomes possible to improve the cooling efficiency and reduce the load on the blower 2.

  In addition, according to the cast concrete cooling device 1 according to the present embodiment, the air supply opening 22 and the hollow steel pipe 5 in which the air duct 3 is installed through the bottom mold 21 provided near the top of the hollow steel pipe 5. Since the exhaust openings 23 for moving the air inside are provided respectively, it is possible to cool the fresh concrete 33 using the internal space of the hollow steel pipe 5 without being interfered with the bottom mold 21. Become.

  Moreover, according to the concrete cooling device 1 according to the present embodiment, the blower duct 3 is connected to the joint 25, the upper duct body 24 that connects the upper connection end of the joint and the blower 2, and the lower connection of the joint 25. The lower duct main body 26 is connected to the end portion and extends downward, and the joint 25 is passed through the air supply opening 22 so as to be locked to the air supply opening. It can be supported by the bottom mold 21.

  In the present embodiment, the lower end of the air duct 3 is positioned in the vicinity of the bottom of the hollow steel pipe 5, but if there is no concern that air stays below the hollow steel pipe 5, the lower end of the air duct 3 is placed at such a place. There is no need to position.

  Rather, if the lower end of the air duct 3 is made to follow the placement height of the fresh concrete 33 by retracting the air duct 3 in accordance with the progress of the concrete work, the cooling efficiency for the fresh concrete is greatly increased. It becomes possible to improve.

  In the present embodiment, the bottom mold 21 is provided with the air supply opening 22 and the exhaust opening 23, but instead, the bottom mold 21 is temporarily removed, and after the concrete work is completed, You may restore it to the original.

  In such a case, since the problem of interference between the air duct 3 and the bottom mold 21 does not occur, the air duct 3 may be appropriately suspended in the hollow steel pipe 5 and installed.

  Further, in the present embodiment, the weight of the lower duct body 26 is supported by the bottom mold 21 by locking the joint 25 to the air supply opening in a state where the joint 25 penetrates the air supply opening 22. However, if the lower duct main body 26 is small in weight and can be suspended from the blower 2, the joint 25 may be simply inserted without being locked to the air supply opening 22.

  Moreover, in this embodiment, although the ventilation duct 3 was each installed in the total of six hollow steel pipes 5, if it replaces with this and fresh concrete 33 can be air-cooled and the temperature crack can be prevented, ventilation will be carried out. The hollow steel pipe 5 in which the duct 3 is installed may be appropriately limited. For example, a case in which the installation of the air duct 3 is omitted for the two hollow steel pipes 5 standing in the center among the six hollow steel pipes 5 can be considered.

DESCRIPTION OF SYMBOLS 1 Cooling device of cast-in concrete in steel pipe and concrete composite structure pier 2 Blower 3 Air blow duct 4 Steel pipe and concrete composite structure pier 5 Hollow steel pipe 6 Concrete frame 21 Bottom form frame 22 Air supply opening 23 Exhaust opening 24 Upper duct body 25 Joint 26 Lower duct body 33 Fresh concrete

Claims (4)

A blower duct disposed in the hollow steel pipe so as to communicate with the inside of the hollow steel pipe erected as a steel pipe constituting a steel pipe / concrete composite structure pier via the lower end and connected to the blower at the upper end And supplying the blower with air from the upper end of the blower duct into the blower duct and feeding the air downward, discharging the air from the lower end of the blower duct and supplying the air into the hollow steel pipe The air supplied to the inside of the hollow steel pipe cools the fresh concrete placed around the hollow steel pipe to form a concrete frame constituting the pier. Casting concrete cooling device for steel pipe-concrete composite structure piers. The cooling device for cast concrete in a steel pipe / concrete composite structure pier according to claim 1, wherein a lower end of the air duct is positioned near a bottom of the hollow steel pipe. In the vicinity of the top of the hollow steel pipe, two openings are formed in a bottom mold that divides the inside of the hollow steel pipe up and down, and one of the two openings is an air supply opening through which the air duct is installed. The cooling apparatus for cast concrete in a steel pipe / concrete composite structure pier according to claim 1, wherein the other is an exhaust opening. The lower duct connected to the lower duct connecting end and the upper duct main body connecting the upper duct end connecting the blower duct to the air supply opening, the upper connecting end of the joint and the blower, and the lower connecting end of the joint The cooling apparatus for cast concrete in a steel pipe / concrete composite structure pier according to claim 3, wherein the cooling apparatus is composed of a duct body and the joint is locked to the air supply opening.

Images