JP2009114824A - Method for placing freshly mixed concrete for seismic strengthening of bridge pier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new high efficiency method for placing fresh mixed concrete, which can improve the quality of the concrete and the design of a concrete surface in concrete lining type seismic strengthening work for a concrete bridge pier. <P>SOLUTION: In fresh mixed concrete placing work, a required number of portable fresh mixed concrete hoppers 7 for placing the fresh mixed concrete are arranged on an upper portion of a form 3; and a detachable fresh mixed concrete charging hose 5 with a proper length corresponding to the placing up height of the fresh mixed concrete is mounted in a fresh mixed concrete exhaust port 14 in the lower portion of the hopper 7. A fresh mixed concrete placing location and the placing up height can be easily changed in a short period of time by a hopper placing system for charging the fresh mixed concrete. This enables the great shortening of a placing construction period and an improvement in the quality of the concrete and the design of the concrete surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a concrete pier-type seismic reinforcement work for a concrete pier that is carried out to prevent a concrete pier such as an expressway or a railway from being destroyed or damaged by an earthquake or the like. This is related to the technical field of placing high-quality, high-efficiency concrete in reinforcement work.

  If a concrete bridge pier of an expressway or railway is collapsed due to an earthquake, or if it does not cause collapse, the scale of the disaster will be extremely large if a condition such as a crack in the concrete frame occurs. This type of disaster, as seen in the Great Hanshin Earthquake, has been severely damaged by expressways and railways, causing not only material transportation, but also major obstacles to transportation, and the restoration work is costly and expensive. There is a big problem that it takes time.

  In order to deal with this, various seismic reinforcement technologies for concrete piers have been researched and developed, and as one of the current reinforcement work methods, the concrete thickness is increased by winding reinforced concrete around concrete piers 1 such as expressways and railways. A concrete hoisting method has been put into practical use in order to increase the strength by carrying out the above.

  In the concrete-winding-type seismic reinforcement work for the concrete pier, the concrete thickening amount is generally about 250 mm, and reinforcing reinforcing bars 2 are arranged in the space between the existing concrete pier 1 and the formwork 3. . In this case, the gap between the surface of the reinforcing reinforcing bar 2 and the inner surface of the mold 3 is about 80 to 90 mm and is very narrow. In addition, the height of a single ready-mixed concrete is generally about 5.4 m due to limitations of formwork strength and vibrators.

  On the other hand, from the viewpoint of ensuring the quality of concrete, the height of ready-mixed concrete is set to be 0.5 to 1.0 m per layer. In order to obtain a uniform concrete, it is necessary to drive the ready-mixed concrete so that the ready-mixed concrete surface is almost horizontal in one section, and to perform vibration compaction uniformly using a vibrator or the like. Also, when placing a large amount of ready-mixed concrete over a wide area, provide as many places as possible to limit the speed at which it can be driven from one location according to the compaction ability, and so that the entire placement section is driven horizontally. Good to do. When there are few driving locations, the driving speed from one driving location increases, and the driving work becomes rough, and there is a high possibility that dense concrete cannot be driven. It is important to adjust the balance in a balanced manner.

  In addition, when the ready-mixed concrete is dropped from a high place or the ready-made concrete is dropped from above on a wall having a large height, the ready-made concrete collides with the formwork 3 and the reinforcing bar 2 and easily causes material separation. Moreover, the concrete adhering to the formwork 3 and the reinforcing bar 2 is hardened, and this may become an obstacle to the subsequent construction or a defect of the structure. In such a case, it is necessary to provide a window frame 12 as an input port at an appropriate place of the mold 3, or to lower a discharge port such as a vertical chute or pump pipe to the vicinity of the driving surface. For this reason, the fall height from the ready-mixed concrete charging hose 5 to the placing surface and the ready-mixed concrete loading position are limited because it is necessary to prevent the separation of the ready-mixed aggregate due to dropping the ready-mixed concrete from a high place.

  In addition, for the purpose of measuring the density of concrete, it is important to sufficiently compact so as not to generate voids around the reinforcing bar 2, the inner surface of the formwork 3, and the surface of the existing concrete frame while giving vibration to the concrete with a vibrator. . Furthermore, it is necessary to measure the unification of the ready-mixed concrete between each layer of the ready-mixed concrete by passing a vibrator through the upper and lower layers.

  In order to realize the necessary items from the viewpoint of ensuring the quality of the concrete, conventionally, the following two methods are generally employed.

  In the first method, as shown in FIG. 10, a plurality of window frames 12 are arranged around the mold frame 3, raw concrete is poured from the window frame 12, and a vibrator is inserted from the top of the mold frame 3. This is a method of launching green concrete sequentially while compacting. However, this method has a problem in that moisture of the ready-mixed concrete leaks from the periphery of the lid of the window frame 12 and defects such as sand running tend to occur on the thickened concrete surface. In addition, there is a problem that the concrete height of the window frame 12 is not uniform and irregularities are generated on the surface of the thickened concrete, or a window frame pattern remains on the surface of the thickened concrete, resulting in poor design.

  In the second method, as shown in FIG. 11, a long ready-mixed concrete charging hose 5 is attached to the tip of the ready-mixed concrete pump hose 4, and the ready-mixed concrete charging hose 5 is connected to the reinforcing bar 2 and the mold from the top of the mold 3. A method of inserting between the frames 3 and placing the ready-mixed concrete while maintaining the fall height limit of 1.5 m or less, inserting a vibrator from the top of the formwork 3 and launching the ready-mixed concrete sequentially It is. However, in this method, since the ready-mixed concrete hose needs to be taken in and out around the existing concrete pier 1 at a certain interval, the ready-mixed concrete pump car boom is moved back and forth each time, and ready-mixed concrete is put in. There is a problem that work efficiency is extremely bad. Further, it takes a lot of time to put in and take out the ready-mixed concrete hose, and there is a problem that compaction is likely to be uneven and the quality of concrete is likely to be hindered.

  As described above, the conventional concrete pouring method for concrete piers with concrete roll-up type seismic retrofitting has a concern from the viewpoint of ensuring the stability of concrete quality, and the efficiency of the concrete pouring work is low. There was a big problem of being extremely bad.

  The present invention was made to solve the above-mentioned important issues in ensuring the quality of the concrete-winding type seismic reinforcement work, and to improve the design of the finished thickened concrete surface and greatly improve the work efficiency. It is an object of the present invention to provide a method for placing ready-mixed concrete in a concrete winding pier type seismic reinforcement work for a concrete pier that is efficient and stable in the narrow gap between the reinforcing bar 2 and the formwork 3.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
As shown in FIG. 1, the method of the present invention according to claim 1 is used to place raw concrete on the upper part of the formwork 3 when placing the ready-mixed concrete for the seismic reinforcement of concrete piers. A portable ready-mixed concrete hopper 7 for placing concrete is arranged, and a detachable ready-mixed concrete loading hose 5 having an appropriate length is attached to the lower portion of the transportable ready-mixed concrete hopper 7 according to the launch height of the ready-mixed concrete. It is a ready-mixed concrete placement method in concrete-winding-type seismic reinforcement work for concrete piers characterized by a hopper-placed method for placing ready-mixed concrete.

  By adopting the above-mentioned ready-mixed concrete hopper placing method, the window frame 12 is not attached to the mold 3, so there are no defects such as window frame traces on the concrete surface or irregularities on the concrete surface, and the concrete surface has high design properties Is obtained. In addition, the ready-mixed concrete can be launched evenly around the pier within 1m per layer within a short time and can be compacted with a vibrator, which stabilizes the quality of earthquake-resistant reinforced concrete. In addition, the time for placing the ready-mixed concrete can be changed by changing the launch height only by replacing the loading hose 5 at the lower part of the portable ready-mixed concrete hopper 7. The working efficiency is improved to about 150 to 200% as compared with the conventional method, and a significant cost reduction can be achieved.

  Further, according to the present invention, a portable ready-mixed concrete hopper 7 that can be installed on the upper surface of the concrete mold 3 has a double-wall structure as the ready-mixed concrete outlet 14 provided below the hopper 7 and has an outer side. Even if one or more air holes 10 are provided in the wall and the ready-mixed concrete hose 5 is hermetically attached to the ready-mixed concrete outlet 14, a vacuum state is caused by the free fall action of ready-mixed concrete due to the inflow of air from the air holes 10. 2. The portable ready-mixed concrete hopper 7 used in the ready-mixed concrete placing method according to claim 1, wherein the ready-mixed concrete hose 5 can be prevented from being crushed and blocked.

  With the hopper structure according to the second aspect, the installation of the ready-mixed concrete charging hose 5 attached to the lower part of the portable ready-mixed concrete hopper 7 whose length is changed in accordance with the placement height of the concrete is provided with a mounting hook 9. Even in the case of the hooking method, even if the hose drop prevention stopper 13 at the tip of the discharge port 14 at the lower part of the portable ready concrete hopper is tightly attached to the upper part of the hose drop prevention stopper, the inflow of air is performed stably. The hose is prevented from collapsing due to the generation of a vacuum part due to the free fall of the ready-mixed concrete, so that the ready-mixed concrete can be supplied stably.

  As described above, according to the method of the present invention, since the window frame 12 is not attached to the mold 3, there is no defect such as window frame traces on the concrete surface or irregularities on the concrete surface, and the design is also high. A concrete surface is obtained. In addition, concrete can be launched evenly around the pier within 1m per layer in a short period of time, so that sufficient time for compaction by the vibrator can be secured and compaction can be performed reliably. Therefore, the quality of seismic reinforced concrete is also stabilized. Moreover, the entire placing time of the ready-mixed concrete is greatly shortened, the working efficiency is improved to about 150 to 200% as compared with the conventional method, and a significant cost reduction can be achieved.

  In this way, the present invention has dramatically improved the method for placing ready-mixed concrete in the concrete winding pier for earthquake resistance reinforcement of concrete piers, and has the effects from the construction work quality aspect, construction cost aspect, and seismic reinforcement strength performance aspect. It is extremely large and contributes to the world by improving the safety against earthquakes of concrete piers such as highways and railways that are installed in the world by high quality construction quality. is there.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view showing a situation in which a first layer of ready-mixed concrete according to an embodiment of the present invention is being placed. FIG. 2 is a front view showing an example of the portable ready-mixed concrete hopper 7 according to one embodiment of the present invention, and FIG. 3 is a side view thereof. FIG. 4 is a front view of an example in which the ready-mixed concrete charging hose 5 is attached to the portable ready-mixed concrete hopper 7 using the hose hooks 9 on both sides, and FIG. 5 is a side view thereof. FIG. 6 shows a case in which the ready-mixed concrete hose 5 is attached to the portable ready-mixed concrete hopper 7 in a tightly-tightened state with a tightening band or wire on the top of the stopper 13 for preventing the hose drop at the outlet of the ready-mixed concrete outlet 14. FIG. 7 is a side view of the above example. FIG. 8 is an arrangement diagram of the portable ready-mixed concrete hopper 7 showing an example of arrangement of the portable ready-mixed concrete hopper 7 in the seismic reinforcement work of the rectangular concrete pier, and FIG. 9 is a portable ready-mixed concrete in the case of the circular concrete pier. FIG. 4 is a layout diagram of the hopper 7.

  In FIG. 1, 1 is a concrete pier which is a target of seismic reinforcement, 2 is a reinforcing bar, and 3 is a formwork. 4 is a front end portion of a ready-mixed concrete hose of a ready-mixed concrete pump truck (not shown), and puts ready-mixed concrete into a portable ready-mixed concrete hopper 7 disposed at the upper part of the mold 3. A ready-mixed concrete charging hose 5 having an appropriate length according to the charging height is attached to the lower part of the portable ready-mixed concrete hopper 7. When the height of the formwork 3 is about 5.4 m, four ready-mixed concrete hose 5 of about 4 m, 3 m, 2 m, and 1 m are prepared and replaced according to the input height at that time. 6 is a portion of the ready-mixed ready-mixed concrete in the first layer.

Below, the raw concrete placement method of the concrete winding type earthquake-proof reinforcement construction of the concrete pier according to the present invention will be described based on FIGS.
In the case of a rectangular pier, as shown in FIG. 8, first, the number of portable ready-mixed concrete hoppers 7 corresponding to the number of ready-mixed concrete-requiring positions necessary for quality are arranged in advance on the formwork 3. The ready-mixed concrete hopper 7 can be easily fixed to the upper part of the mold using a hook 8 attached to the hopper 7 for hooking and fixing the hopper 7 to a reinforcing bar. (1)-(8) beside the symbol of the portable ready-mixed concrete hopper 7 in FIG. 8 shows the order of placing ready-mixed concrete in each layer of the ready-mixed concrete launch. When placing the first layer of ready-mixed concrete, the placing work is performed while moving the charging hose 4 of the ready-mixed concrete pump car onto the portable ready-mixed concrete hopper 7 in order from (1). When the placement in the portable ready-mixed concrete hopper 7 of (1) is completed, the ready-mixed concrete pump vehicle immediately moves the input position to the portable ready-mixed concrete hopper 7 of (2) and continues the placing. At the point (1), the vibrator is inserted immediately after the pump car moves to the position (2) to perform the necessary closing and hardening work. At the same time, the 4 m long charging hose 5 attached to the portable ready-mixed concrete hopper 7 is removed and replaced with the 3 m charging hose 5 for the next charging height. During the hose replacement work, the ready-mixed concrete placement work is performed at the location (2), and during the hose replacement work time, the ready-mixed concrete placement work can be performed in parallel without interfering with the hose replacement work time. Yes, work efficiency is greatly improved. Thereafter, when the placement from (2) to (4) is completed, the first layer placement is completed, and the second layer placement is performed in the order of (5) to (8). The same work is repeated for the third and subsequent layers, and the concrete is placed by launching to the final height.

  In the embodiment in the case of a circular pier, based on an arrangement example as shown in FIG. 9, a work similar to FIG.

  As explained above, in concrete winding pier-type seismic reinforcement work for concrete piers, a conventional mold is placed by performing a ready-mixed concrete placing operation using a hopper placing method using the portable ready-mixed concrete hopper 7 of the present invention. By installing a number of window frames 12 on the frame 3 and placing a long hose directly connected to the pump car from the top of the mold 3, the efficiency is extremely poor, and there is a problem in terms of quality and design. As a result, the ready-mixed concrete placing work has been greatly improved, and high-quality and highly efficient ready-mixed concrete placing work can be carried out.

Sectional drawing which shows the condition during the placement of the 1st layer ready-mixed concrete of one Example of this invention The front view which shows the example of the portable ready-mixed concrete hopper of one Example of this invention The side view which shows the example of the portable ready-mixed concrete hopper of one Example of this invention Front view of an example of installing a ready-mixed concrete hose on a portable ready-mixed concrete hopper using hose hooks on both sides Side view of an example of a ready-mixed concrete hose attached to a portable ready-mixed concrete hopper using hose hooks on both sides Front view of an example of a ready-mixed concrete hose attached to a transportable ready-mixed concrete hopper, sealed and tied to a ready-mixed concrete outlet Side view of an example when a ready-mixed concrete hose is attached to a transportable ready-mixed concrete hopper and sealed to a ready-mixed concrete outlet. The portable ready concrete hopper arrangement | positioning figure which shows the example of arrangement | positioning of the portable ready concrete hopper in the concrete winding-type earthquake-proof reinforcement construction of a rectangular concrete bridge pier. (1) to (8) beside the portable ready-mixed concrete hopper in the figure shows an example of the order of hitting ready-mixed concrete. The portable ready concrete hopper arrangement figure which shows the example of arrangement | positioning of the portable ready concrete hopper in the earthquake-proof reinforcement construction of a circular concrete pier. (1) to (4) next to the portable ready-mixed concrete hopper in the figure shows an example of the order of hitting ready-mixed concrete. Conceptual diagram in the case of placing using a window frame 12 for placing in a mold as an example of a method for placing concrete in a conventional concrete pier concrete-wrapped seismic reinforcement work As an example of a method for placing ready-mixed concrete in a conventional concrete pier, the direct feed of a ready-mixed pump hose and a long ready-mixed concrete hose attached to the top of the formwork at the top Conceptual diagram when placing

Explanation of symbols

1 Existing concrete bridge piers to be seismically reinforced 2 Reinforcement reinforcing bars assembled for seismic reinforcement 3 Forms for seismic reinforcement work 4 Ready-mixed hose for ready-mixed concrete pump car 5 Ready-mixed concrete hose 6 Ready-cast concrete Cleat 7 Portable ready-mix concrete hopper 8 Hook for hooking and fixing transportable ready-mixed concrete hopper 9 Reinforced concrete hose hook 10 Air inlet hole 11 Fasteners such as wire 12 Raw concrete casting window frame opened in the mold 13 Stopper 14 for preventing hose from falling when the concrete hose is fastened and attached to the raw concrete under the portable ready concrete hopper Concrete outlet

Claims (2)

  A portable ready-mixed concrete hopper for placing ready-mixed concrete is placed in the upper part of the formwork and placed under the portable ready-made concrete hopper. In concrete roll-up type seismic reinforcement work for concrete piers, which features a hopper placing method in which ready-mixed concrete hose is installed by attaching a detachable ready-mixed concrete hose of an appropriate length according to the launch height of ready-mixed concrete Raw concrete placement method.   In a portable ready-mixed concrete hopper that can be installed on the top of a concrete formwork, the ready-mixed concrete outlet located below the hopper has a double wall structure, and one or more air holes are provided in the outer wall, Even if the ready-mixed concrete hose is hermetically attached, it can prevent the ready-mixed concrete input hose from being crushed and blocked due to the free flow of the ready-mixed concrete due to the inflow of air from the air hole. A portable ready-mixed concrete hopper for use in the ready-mixed concrete placing method according to claim 1.

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