JP6671863B2 - Manufacturing method of concrete filled steel pipe, pressurizing device and concrete leakage limiting device - Google Patents

Description

  The present invention relates to a method for manufacturing a concrete-filled steel pipe for pressurizing concrete filled in a steel pipe, a concrete-filled steel pipe, a pressurizing device, and a concrete leakage limiting device.

Concrete filling of steel pipe columns in concrete filled steel tube (CFT) construction can be carried out by either a press-fitting method or a drop-in filling method. Generally, a diaphragm is provided inside the column-beam joint.However, it is known that when filling concrete, voids, air pockets, etc. are generated immediately below the diaphragm, causing inevitable fluctuations in concrete strength. ing. In order to secure the strength reduction due to the strength fluctuation, it is prescribed in JASS5 and the like that the strength correction value (Sc value) of concrete is set to 10 to 15 N / mm ² , and the nominal strength of concrete (= Fq + Sc). Becomes very large, and the cost of concrete material increases. Note that Fq is the quality reference strength of concrete.

  Here, if it is possible to suppress the occurrence of voids, air pockets, and the like immediately below the diaphragm, the fluctuation range of the strength of the concrete is reduced, and as a result, the Sc value can be set small, and the nominal strength of the concrete can be reduced. Material costs can be reduced.

  Patent Literature 1 discloses a building method in which a prestress is introduced into a filled concrete steel pipe column capable of increasing an adhesive force between the steel pipe and the filled concrete and increasing an axial load ratio of the filled concrete.

Patent No. 2860727

  In order to suppress the occurrence of voids, air pockets, etc. immediately below the diaphragm and reduce fluctuations in concrete strength, it is necessary to pressurize the concrete filled in the steel pipe before the fluidity of the concrete is lost. Considered to be effective. On the other hand, in the construction method of Patent Literature 1, concrete is filled in a steel pipe column, a pressure-resistant lid is attached on a closing plate of the steel pipe column, and a closed space is formed on the filled concrete. The pressurized fluid is supplied to the concrete and pressurizes the upper surface of the uncured concrete, which complicates the work of manufacturing the concrete-filled steel tubular column.

  In view of the above circumstances, an object of the present invention is to provide a method of manufacturing a concrete-filled steel pipe capable of manufacturing a concrete-filled steel pipe made of pressurized concrete by a simple operation, a concrete-filled steel pipe, a pressurizing device, and a concrete leakage limiting device. I do.

  In order to solve the above-mentioned problems, a method for manufacturing a concrete-filled steel pipe of the present invention includes the steps of: filling concrete in a steel pipe; connecting a pressurizing device to an upper portion of the steel pipe; Pressurizing the upper surface of the concrete in a flowable state filled in the steel pipe.

  With the above configuration, since the concrete filled in the steel pipe is pressurized by the pressurizing device connected to the upper part of the steel pipe, advanced operations such as formation of a closed space and supply of pressurized fluid are not required, and A concrete-filled steel pipe made of compacted concrete can be manufactured by a simple operation, and fluctuations in concrete strength can be reduced. Further, since a pressing device is connected to the steel pipe, a reaction force received by the pressing device due to the pressing of the concrete can be applied to the steel pipe.

  Before the concrete is filled in the steel pipe, a fluidizing agent may be added to the concrete to secure the fluidity. According to this, the time management for the state of ensuring the fluidity of the concrete can be accurately performed, and the effect of pressurizing the concrete can be reliably generated.

  The pressurization of the concrete by the pressurizing device may be terminated at a stage before the concrete loses its fluidity and congeals. According to this, a concrete-filled steel pipe can be manufactured in a short time as compared with the method of waiting until the concrete is set and finishing the pressurization.

  A mesh member is laid on the base plate fixed to the bottom of the steel pipe, concrete is filled on the mesh member, and excess water is discharged through holes formed in the mesh member and the base plate. Good. According to this, it is possible to prevent the concrete from leaking from the hole due to the pressurization of the concrete by the mesh member.

  Further, a concrete-filled steel pipe of the present invention is characterized by being produced by the method for producing a concrete-filled steel pipe according to any one of the above.

  Further, the pressurizing device of the present invention is a pressurizing device used for the method of manufacturing the concrete-filled steel pipe, and includes a main body, a moving pressurizing unit moving with respect to the main body, and a moving pressurizing unit. It is characterized by comprising a pressing plate portion provided at a tip portion and in contact with an upper surface portion of the concrete, and a connecting portion for connecting the main body portion to the steel pipe.

  With the above configuration, since a connecting portion for connecting the main body portion to the steel pipe is provided, the reaction force received by the pressurizing device due to the pressurization of the concrete is applied to the steel pipe through the connecting portion. Can be.

  A hole may be formed in the pressing plate portion to allow excess water and air in the concrete to escape upward. According to this, surplus water and air in the concrete can be discharged through the holes.

  A sliding member that contacts the inner surface of the steel pipe may be provided around the pressing plate portion. According to this, even when the dimensional accuracy of the inner surface of the steel pipe near the peripheral portion of the pressing plate portion is low and a large gap is opened between the peripheral portion and the inner surface, the gap is eliminated by the sliding contact member. Can be.

  The pressing plate portion may be configured to be dividable or deformable. According to this, it is possible to assemble or expand the divided pressing plate portion or the compactly deformed pressing plate portion even after putting it in the steel pipe. For this reason, even when the mounting portion for mounting the pressurizing device is provided inside the steel pipe, the pressing plate portion may be formed into a pressable shape after being inserted into the steel pipe avoiding the mounting portion. it can.

  Further, a concrete leakage restricting device according to the present invention is a concrete leakage restricting device used in the method for producing a concrete-filled steel pipe according to any one of the above, wherein the plug fits into a steam vent formed in the steel pipe. And a fastening member for fastening the plug-shaped portion to the steel pipe. The plug-shaped portion restricts leakage of concrete but has a hole for allowing excess water and air to pass therethrough. It is formed so as to communicate with the outside.

  With the above configuration, it is possible to prevent the concrete from leaking into the steam vent hole and to be hardened, and to discharge excess water and air in the concrete from the steam vent hole. Furthermore, by discharging the surplus water, the water-cement ratio of the filled concrete is reduced, and the strength of the concrete is increased in combination with the improvement of the density by pressing.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to produce a concrete-filled steel pipe made of pressurized concrete with a simple operation, and it is possible to reduce the variation in the strength of concrete, and so on.

It is explanatory drawing explaining the manufacturing method of the concrete filling steel pipe which concerns on embodiment of this invention. 1A is a schematic cross-sectional view taken along line AA of FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along line BB of FIG. 1A is a schematic sectional view taken along the line DD of FIG. 1, and FIG. 2B is a schematic sectional view taken along the line CC of FIG. It is a figure explaining the manufacturing method of the concrete filling steel pipe concerning the embodiment of the present invention, and the same figure (A) is a schematic plan view of a press plate part, and the same figure (B) is the same side view. It is a figure explaining the manufacturing method of the concrete filling steel pipe which concerns on embodiment of this invention, Comprising: It is a schematic sectional drawing which showed the concrete leak-restriction device attached to the steam vent hole.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, a method of manufacturing a concrete-filled steel pipe according to this embodiment includes a step of filling concrete 2 in a steel pipe column 1, and a step of connecting a pressurizing device 3 to an upper portion of the steel pipe column 1. Pressurizing the upper surface of the concrete 2 in a fluid state filled in the steel pipe column 1 by the pressurizing device 3.

  The steel pipe column 1 has, for example, a rectangular tube shape, and the base plate 11 of the steel pipe column 1 is disposed on a base mortar 72 applied on a column die 71. Further, on the upper surface of the base mortar 72, as shown in FIG. 2A, a groove (or a tube) 72a reaching the edge of the base mortar 72 is formed. Above the groove 72a, a hole 11a formed in the base plate 11 in a vertical direction is located, and rainwater or the like penetrating into the steel pipe column 1 passes through the hole 11a and the groove 72a. It is discharged outside. Further, a mesh member 73 is installed on the base plate 11 in the steel pipe column 1 before the concrete 2 is filled. The mesh member 73 has, for example, a coarseness that allows water to permeate but does not allow the fine aggregate (sand or the like) and the coarse aggregate of the concrete to permeate. Further, on the base plate 11, a hole 11b for an anchor bolt is formed.

  On the peripheral wall 12 of the steel pipe column 1, a steam vent hole 12a is formed in the horizontal direction. When a fire occurs and the concrete (after hardening) is heated, steam generated by evaporation of water in the concrete is discharged from the steam vent hole 12a.

  As shown in FIG. 2B, an inner diaphragm 13 is joined to the steel pipe column 1 by welding, and a beam 74 made of, for example, an H-shaped steel is fixed to the inner diaphragm 13. The inner diaphragm 13 is formed with a casting hole 13a through which the concrete 2 to be filled passes and a hole 13b through which excess water or air in the concrete 2 passes in the vertical direction.

  As shown in FIG. 3A, for example, four mounting portions 14 are provided on the upper surface of the peripheral wall 12 of the steel pipe column 1 on each surface of the rectangular steel pipe, that is, perpendicular to the central axis of the steel pipe column 1. Are fixed at intervals of 90 degrees around the central axis by welding or the like. For example, an insertion hole for a bolt / nut 141 is formed in an upper portion of each mounting portion 14. Then, the connecting portion 31 of the pressurizing device 3 is fixed to the mounting portion 14 by the bolt / nut 141 attached to the insertion hole for the bolt / nut 141.

  The connecting portion 31 of the pressurizing device 3 has, for example, a cross shape in a plan view, and each of four ends can be fixed to the mounting portion 14 by the bolt / nut 141. The back side (upper side) of the main body 32 of the pressurizing device 3 is fixed to the connecting portion 31 of the pressurizing device 3 by welding or the like.

  The main body 32 is provided with a moving pressure unit 33 that moves with respect to the main body 32. The moving pressurizing section 33 includes, for example, a plunger section that can go out of the main body section 32 and a piston section that exists inside the main body section 32 (in the cylinder). Further, a spring may be provided in the main body 32 to urge the moving and pressurizing section 33 in a direction of being housed in the main body 32. Furthermore, the main body 32 is connected to a manual pump 300 installed on a scaffold (for example, a deck steel plate) 75 via a pressure-resistant hose (not shown). By manually operating the pump 300, the pressure liquid can be supplied to the main body 32.

  The supply of the pressurized liquid allows the moving and pressurizing unit 33 to move against the bias of the spring and move out of the main body 32. On the other hand, when a switching operation in which the return of the pressurized liquid is permitted is performed in the pump 300, the moving pressurizing unit 33 moves in a direction accommodated in the main body unit 32 by the bias of the spring, The pressurized liquid in the main body 32 returns to the pump 300.

  A pressing plate portion 34 that contacts the upper surface portion of the concrete 2 is provided on the tip end side (lower end side) of the moving pressing portion 33. The pressing plate portion 34 has a square shape (circular if the steel pipe column is circular) conforming to the inner surface shape of the steel pipe column 1, and is provided between a peripheral edge thereof and the inner surface of the steel pipe column 1. Has a gap formed. The gap is desirably set to, for example, about 1 mm, but is not limited to this. In this embodiment, a sliding contact member 34b that comes into contact with the inner surface of the steel pipe column 1 is provided around the pressing plate portion 34. The sliding contact member 34b is made of, for example, an O-ring or packing made of rubber. The pressing plate portion 34 is formed with a hole 34a through which excess water or air generated when the concrete 2 is pressed is discharged upward.

  In the step of filling the steel pipe column 1 with the concrete 2, the concrete 2 may be charged from the opening at the upper end of the steel pipe column 1, or the concrete 2 may be press-fitted from the lower side of the steel pipe column 1. You may. This charging or press-fitting is performed before the pressurizing device 3 is fixed to the upper end of the steel pipe column 1.

  When the concrete 2 is filled into the steel pipe column 1 to a predetermined height, an operation of connecting the pressurizing device 3 to the upper part of the steel pipe column 1 is performed. In this work, for example, while the pressurizing device 3 is lifted by a crane, a person working on the scaffold 75 speaks with a person operating the crane, and the pressing plate portion of the pressurizing device 3 34 is positioned at the upper end opening of the steel pipe column 1 and the pressurizing device 3 is lowered. Due to this lowering, the pressing plate portion 34 enters the inside of the steel pipe column 1, and the connecting portion 31 is received by the stopper portion 14 a formed on the mounting portion 14. In this state, the insertion hole for the bolt / nut 141 in the connection portion 31 matches the position of the insertion hole for the bolt / nut 141 formed in the attachment portion 14. This allows the pressure device 3 to be fixed to the mounting portion 14 by inserting the bolt / nut 141 into the insertion hole.

  Next, the pump 300 is operated, and the pressurizing device 3 pressurizes the upper surface portion of the fluid concrete 2 filled in the steel pipe column 1 with the fluidity. There is no particular need to perform this immediately after fixing 3 to the mounting portion 14. Since the concrete 2 is pressurized and settles even under its own weight, the concrete 2 may be settled after a while and then pressurized by the pressurizing device 3. However, the pressurization of the concrete 2 by the pressurizing device 3 is performed within the time during which the fluidity of the concrete 2 is ensured. The upper limit of the pressure applied to the concrete 2 is set to a value sufficiently smaller than the allowable stress of the steel pipe column 1.

  It is desirable that a constant pressure be continuously applied to the concrete 2 by the pressurizing device 3 even when the moving pressurizing unit 33 moves due to the sedimentation of the concrete 2 by pressurization. For example, instead of the manual pump 300, an electric pump or the like that can make the supply liquid pressure constant may be used so that the constant pressure is maintained without being affected by the sedimentation. Further, a constant pressure may be maintained by using a hydraulic pump driven by compressed air from an air compressor. When using the manual pump 300, the operator may monitor the value of the pressure gauge and perform an additional manual operation so as to compensate for the pressure when the pressure decreases. On the other hand, the pressure may be allowed to decrease, and the pressurization may be terminated when the numerical value of the pressure gauge falls within a predetermined range.

  According to the above-described method, the concrete 2 filled in the steel pipe column 1 is pressurized by the pressurizing device 3 connected to the upper part of the steel pipe column 1. A simple operation is unnecessary, and a concrete-filled steel pipe made of pressurized concrete can be manufactured by a simple operation, and fluctuations in the strength of concrete can be reduced. Further, since the pressurizing device 3 is connected to the upper part of the steel pipe column 1, the reaction force received by the pressurizing device 3 due to the pressurization of the concrete 2 can be applied to the steel pipe column 1.

  Here, a fluidizing agent may be added to a stage before the concrete is filled in the steel pipe column 1, for example, a concrete being stirred by an agitator wheel to ensure fluidity. According to this, the time management of the fluidity securing state of the concrete 2 can be accurately performed, and the effect of pressurizing the concrete 2 can be reliably generated.

  The pressurization of the concrete 2 by the pressurizing device 3 may be terminated before the concrete 2 loses its fluidity and congeals. According to this, a concrete-filled steel pipe can be manufactured in a short time as compared with a construction method in which the pressurization is terminated after the concrete 2 has set. The determination of the end of the fluidity of the concrete 2 can be made by using existing test data and the like, and when the above-mentioned fluidizing agent is used, the fluidity retention indicated by the used fluidizing agent is used. You can judge by referring to the time.

  When the mesh member 73 is laid on the upper side of the base plate 11, concrete 2 is filled on the mesh member 73, and excess water is discharged from holes 11a formed in the base plate 11. The mesh member 73 can prevent the concrete 2 from leaking from the hole 11a due to the pressure.

  And if it is the said pressurizing device 3, since it has the connection part 31 for connecting the said main-body part 32 to the said steel pipe pillar 1, the reaction force which the said pressurizing device 3 receives by the pressurization of the said concrete 2 will be described. The steel tube column 1 can be borne by the connecting portion 31.

  Further, when the pressing plate portion 34 is formed with a hole 34a through which excess water and air in the concrete 2 is drained upward, the excess water and air in the concrete 2 can be discharged through the hole 34a. Can be.

  In addition, when the sliding contact member 34b that comes into contact with the inner surface of the steel pipe column 1 is provided around the pressing plate portion 34, the dimensional accuracy of the inner surface of the steel pipe near the peripheral portion of the pressing plate portion 34 is low, Even when a large gap is formed between the peripheral portion and the inner surface, the gap can be eliminated or the gap can be reduced by the sliding contact member 34b.

  Next, another embodiment will be described. FIG. 4A is a plan view showing a split type pressing plate portion 340, and FIG. 4B is a front view. The pressing plate portion 340 is provided so as to be separable from the moving pressing portion 33, and may have a circular fitting concave portion 340a into which the tip of the moving pressing portion 33 fits. The pressing plate portion 340 includes four quadrangular divided portions 341, but may include four triangular divided portions. If the steel pipe column 1 has a cylindrical shape, the divided portion will be formed in a fan shape. The number of divisions is not limited to four, but may be two, three, five, six, or the like. In addition, the shape of each divided portion may not be the same as each other.

  The quadrangular division parts 341 have the same shape as each other. Further, each of the divided portions 341 is provided with a rising portion 341a at an upper surface portion of an edge on a side to be joined to each other. An insertion hole for a bolt / nut 432 is formed in the rising portion 341a, and the four divided portions 341 are joined to each other by the bolt / nut 432 provided through the insertion hole.

  Even if there is a gap at the joint of each of the divided portions 341, there is no problem as long as this gap is useful for removing excess water or air. In addition, since such a gap is allowed, the divided portions can be connected to each other by an engaging structure using pins, hooks, hooks, or the like, instead of the strong connection by the bolts and nuts 432. .

  When the split type pressing plate portion 340 is used, the pressing plate portion 340 can be assembled after being inserted into the steel pipe column 1. For this reason, even when the mounting portion 14 for mounting the pressurizing device 3 is provided in the steel pipe column 1, after the pressing plate portion 340 is inserted into the steel pipe column 1 avoiding the mounting portion 14. Can be assembled. That is, the method of providing the mounting portion 14 in the steel pipe column 1 can be executed without any problem. After the pressing process on the concrete 2 is completed, the pressing plate portion 340 of the split type may be split and taken out of the steel pipe column 1 or when the subsequent concrete filling work is not performed. It may be left in the steel pipe column 1.

  Not limited to such division, the pressing plate portion may be configured to be deformable. For example, a structure that can be folded using a hinge may be used. Further, for example, a structure in which a plurality of fan-shaped members are rotatably provided around an axis (a structure used as a pan dropping lid) may be employed.

  Next, another embodiment will be described. In this embodiment, a concrete leakage restricting device 5 is provided in a steam vent hole 12a formed in a peripheral wall 12 of the steel pipe column 1. The applicant of the present application has previously proposed a press-fitting concrete leakage prevention structure (see Japanese Patent Application Laid-Open No. 11-303399). The press-in concrete leakage prevention structure also prevents excess water and air from being discharged from the steam vent hole 12a, whereas the concrete leakage limiting device 5 prevents concrete 2 from leaking from the steam vent hole 12a. While allowing excess water and air to escape. In addition, the concrete is prevented from leaking into the steam vent hole 12a and hardening.

  The concrete leakage limiting device 5 includes a plug-shaped portion 51 that fits into a steam vent hole 12 a formed in the peripheral wall 12 of the steel pipe column 1, and a fastening member 52 that fastens the plug-shaped portion 51 to the steel pipe column 1. And The plug-shaped portion 51 is formed with a hole 51a that restricts leakage of concrete but allows excess water and air to pass from inside the steel pipe column 1 to outside the pipe. The hole 51a may be provided with a drainable plug (a coarse fiber plug or the like). A hook (an uneven portion or the like) may be formed on the inner surface of the hole 51a so that the stopper does not move. A flange 51 b is formed on the outer periphery of the plug 51, and the flange 51 b is pressed toward the peripheral wall 12 by the fastening member 52. The fastening member 52 can be configured using a belt. In addition, since it is difficult to press the flat portion of the square tubular steel pipe column with the belt, a structure using a rigid L-shaped angle material or the like at the flat portion may be adopted. .

  The embodiments of the present invention have been described with reference to the drawings. However, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same range as the present invention or within an equivalent range.

1 steel pipe column (steel pipe)
Reference Signs List 11 Base plate 11a Hole 12 Peripheral wall 12a Steam release hole 13 Inner diaphragm 13a Driving port 14 Mounting portion 2 Concrete 3 Pressurizing device 31 Connecting portion 32 Main body portion 33 Moving pressing portion 34 Press plate portion 34a Hole 340 Press plate portion 5 Concrete Leakage control device 51 Plug-shaped part 52 Fastening member

Claims (7)

  A step of filling concrete into the steel pipe, a step of connecting a pressurizing device to an upper part of the steel pipe, and a step of pressing the upper surface of the fluid concrete filled in the steel pipe by the pressurizing device And pressurizing the concrete by the pressurizing device before the concrete loses its fluidity and congeals.   A step of filling concrete into the steel pipe, a step of connecting a pressurizing device to an upper part of the steel pipe, and a step of pressing the upper surface of the fluid concrete filled in the steel pipe by the pressurizing device A net member is laid over a base plate fixed to the bottom of the steel pipe, concrete is filled on the net member, and excess water is discharged through holes formed in the net member and the base plate. A method for producing a concrete filled steel pipe.   3. The method for producing a concrete-filled steel pipe according to claim 1 or 2, wherein a fluidizing agent is added to the concrete at a stage before the concrete is filled in the steel pipe to ensure fluidity. How to make a filled steel pipe. A step of filling concrete into the steel pipe, a step of connecting a pressurizing device to an upper part of the steel pipe, and a step of pressing the upper surface of the fluid concrete filled in the steel pipe by the pressurizing device A pressurizing device used in a method for producing a concrete-filled steel pipe having
A main body portion, a moving pressurizing portion that moves with respect to the main body portion, a pressing plate portion provided at a distal end portion of the moving pressurizing portion and in contact with an upper surface portion of the concrete, and the main body portion being connected to the steel pipe. A pressurizing device comprising: a connecting portion for connecting; and a sliding contact member provided around the pressing plate portion and in contact with an inner surface of the steel pipe. A step of filling concrete into the steel pipe, a step of connecting a pressurizing device to an upper part of the steel pipe, and a step of pressing the upper surface of the fluid concrete filled in the steel pipe by the pressurizing device A pressurizing device used in a method for producing a concrete-filled steel pipe having
A main body portion, a moving pressurizing portion that moves with respect to the main body portion, a pressing plate portion provided at a distal end portion of the moving pressurizing portion and in contact with an upper surface portion of the concrete, and the main body portion being connected to the steel pipe. And a connecting portion for connecting, wherein the pressing plate portion is configured to be splittable or deformable. The pressurizing device according to claim 4 or 5 , wherein a hole is formed in the pressing plate portion to allow excess water and air in the concrete to escape upward. A step of filling concrete into the steel pipe, a step of connecting a pressurizing device to an upper part of the steel pipe, and a step of pressing the upper surface of the fluid concrete filled in the steel pipe by the pressurizing device A concrete leakage limiting device used in the method for producing a concrete-filled steel pipe having
It has a plug-shaped part that fits into a steam vent hole formed in the steel pipe, and a fastening member that fastens the plug-shaped part to the steel pipe, and the plug-shaped part restricts concrete leakage. A concrete leakage limiting device, wherein a hole through which surplus water and air pass is formed so as to communicate from inside the steel pipe to outside the steel pipe.

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