JP2016089341A - Method of manufacturing precast member, and precast member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a precast member, which can decrease weight of a member to be conveyed and reduce the number of precast members on a job site, and the precast member.SOLUTION: A precast member 10 is a rectangular precast member that constitutes a wall of an LNG tank. The precast member 10 includes a frame member 20 that has a hole part 21a and that is formed like a rectangular frame, and concrete C that is placed inside the hole part 21a in a state in which the frame member 20 is arranged in such a manner that the hole part 21a is directed upward.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a precast member constituting a wall portion of a structure and a precast member.

  JP-A-8-3932 describes a ground cover construction method using a precast floor board. In this ground cover construction method, a precast floor board in which reinforcing bars and screw cylinders projecting upward are embedded, and two concrete blocks connected by reinforcing bars so as to be parallel to each other are manufactured in advance. Then, the manufactured precast floor board and the two concrete blocks are carried into the work site and construction is performed. In this construction, concrete is placed in a space defined by an end portion of a precast floor board and two concrete blocks.

  Japanese Unexamined Patent Application Publication No. 2008-115667 describes a tunnel repair method using a tunnel repair lining plate. This tunnel repair lining plate is composed of a top end panel, two side wall panels, and a bottom plate panel. The top panel, the two side wall panels, and the bottom panel are formed by dividing one panel into four. Moreover, the top end panel, the side wall panel, and the bottom plate panel are all made of precast concrete.

  Japanese Patent Laid-Open No. 2002-70135 describes a large box culvert having a culvert body precast at a factory. The culvert body has a rectangular tunnel shape, and an open portion is formed on the bottom surface of the culvert body. In this open part, reinforcing bars embedded in the culvert body are arranged in a lattice pattern. In addition, concrete is cast on the open portion in the field, whereby a bottom plate portion having a required thickness is manufactured.

JP-A-8-3932 JP 2008-115667 A JP 2002-70135 A

  The concrete member as described above is manufactured in advance in a factory and then transported to the site. This concrete member is transported to the site by a trailer or the like. Here, when the weight of the concrete member placed on the trailer or the like is large, there arises a problem that the member cannot be efficiently transported to the site. In the field, construction is performed by installing a plurality of precast members. Here, when there are a large number of precast members installed at the site, the precast members cannot be installed efficiently, causing a problem that the construction period is prolonged.

  This invention is made | formed in view of the above problems, and provides the manufacturing method of a precast member and the precast member which can reduce the number of the precast members in the field while reducing the member to convey. Is an issue.

  The method for producing a precast member according to the present invention is a method for producing a precast member for completing a rectangular precast member on site, so that the hole of the frame member formed in advance in a rectangular frame shape faces upward. A step of arranging the frame member, and a step of placing concrete inside the hole of the frame member.

  In the method for manufacturing a precast member according to the present invention, the frame member is arranged so that the hole portion faces upward, and then the concrete is cast inside the hole portion, whereby the precast member is manufactured. Therefore, a frame member having a hole can be manufactured in advance at a factory or the like, and the frame member can be transported to the site. Therefore, the member to convey can be reduced in weight compared with the member which does not have a hole. That is, since the weight of the member placed on the trailer or the like can be reduced, the member can be efficiently transported to the site. Moreover, since the precast member is manufactured by placing concrete inside the hole of the frame member at the site, a precast member larger than the conventional precast member can be completed at the site. Thus, by completing a larger precast member on site, the number of precast members on site can be reduced. Therefore, the work period of the work of installing a plurality of precast members can be shortened, and the workability can be improved. Thus, the member can be reduced in weight at the time of conveyance, the precast member can be enlarged on the site, and the number of precast members can be reduced to improve the workability.

  Moreover, you may further provide the process of arrange | positioning the flat part for arrange | positioning a frame member in the field production yard provided in the field so that the said hole part may face upwards.

  The step of arranging the frame member may further include a step of forming the frame member by connecting a plurality of block members in a frame shape. In this case, since a plurality of block members can be simultaneously transported to the site, the transported members can be further reduced in weight. In addition, since the frame member is formed by connecting a plurality of block members at the site, a precast member having a larger size can be completed at the site. Therefore, the number of precast members on site can be further reduced.

  Further, in the step of forming the frame member, the first block member and the second block member are arranged so as to face each other, and one end of the first block member and one end of the second block member are connected to the first block member. The frame member may be formed by connecting the other end of the first block member and the other end of the second block member with the second mold form. In this case, the two opposite sides of the frame member are the first block member and the second block member, and the remaining two sides are the first mold frame and the second mold frame. Thus, the two sides of the frame member are the first mold frame and the second mold frame. Therefore, the number of block members to be conveyed can be reduced as compared with the case where all sides of the frame member are block members. Therefore, the member to be conveyed can be further reduced. Furthermore, since the number of block members to be conveyed can be reduced, the members can be conveyed more efficiently.

  In addition, a plurality of reinforcing bars are embedded in the frame member in advance, and the plurality of reinforcing bars may intersect each other inside the hole before the step of placing concrete. In this case, the precast member can be completed simply by placing concrete in the hole. Therefore, the workability on site can be further improved.

  Further, before the step of placing concrete, a plate-like member that closes the lower side of the hole may be attached to the frame member. In this case, at the site, the lower side of the hole is closed by the plate-like member, and the concrete can be placed from the upper side of the hole. In other words, the plate-like member can be used as a mold for closing the hole when placing concrete on site. Therefore, since it is possible to save the trouble of installing the lower mold or the base plate as the flat portion, it is possible to further improve the workability at the site.

  A precast member according to the present invention is a rectangular precast member constituting a wall of a structure, and includes a frame member having a hole and formed in a rectangular frame shape, and a frame member so that the hole faces upward And concrete that is placed inside the hole in a state where is disposed.

  In the precast member according to the present invention, the frame member is arranged so that the hole portion faces upward, and then concrete is placed inside the hole portion to form a rectangular precast member. Accordingly, since the frame member can be manufactured in advance at a factory or the like and transported to the site, the transporting member can be reduced in weight compared to a member having no hole. Therefore, the weight of the member placed on the trailer or the like can be reduced, and the member can be efficiently transported to the site. Moreover, since a precast member can be manufactured by placing concrete inside the hole of the frame member at the site, it is possible to complete a precast member larger than the conventional precast member at the site. Thus, by manufacturing a larger precast member, the number of precast members can be reduced on site. Therefore, the work period of the work of installing a plurality of precast members can be shortened, and the workability can be improved. Thus, the member can be reduced in weight at the time of conveyance, the precast member can be enlarged on the site, and the number of precast members can be reduced to improve the workability.

  The frame member may be formed by connecting a plurality of block members transported to the site in a frame shape. In this case, since the member to be conveyed can be further reduced in weight, a plurality of block members can be efficiently conveyed to the site. In addition, since the frame member is formed by connecting a plurality of block members at the site, a precast member having a larger size can be completed at the site. Therefore, the number of precast members on site can be further reduced.

  The frame member includes a first block member and a second block member that face each other, a first mold that connects one end of the first block member and one end of the second block member, and a first And a second mold that connects the other end of the block member and the other end of the second block member. In this case, the two opposite sides of the frame member are the first block member and the second block member, and the remaining two sides are the first mold frame and the second mold frame. Thus, the two sides of the frame member are the first mold frame and the second mold frame. Therefore, the number of block members to be conveyed can be reduced as compared with the case where all sides of the frame member are block members. Therefore, the member to be conveyed can be further reduced in weight. Furthermore, since the number of block members to be conveyed can be reduced, the members can be conveyed more efficiently.

  Further, the frame member may include a plurality of reinforcing bars embedded so as to cross each other inside the hole. In this case, the precast member can be completed simply by placing concrete in the hole. Therefore, the workability on site can be further improved.

  The frame member may include a plate-like member that closes the lower side of the hole. In this case, before the concrete is placed in the hole, the plate-like member can block the lower side of the hole so that the concrete can be placed from the upper side of the hole. In other words, the plate-like member can be used as a lower mold for closing the hole side at the time of placing concrete on site. Therefore, since it is possible to save the trouble of installing the lower mold or the base plate as the flat portion, it is possible to further improve the workability at the site.

  ADVANTAGE OF THE INVENTION According to this invention, while reducing the member to convey, the number of precast members in the field can be reduced.

It is a perspective view which shows the LNG tank which is an example of the building comprised by the precast member which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the LNG tank of FIG. (A) is a top view which shows the precast member which concerns on 1st Embodiment. (B) is a top view which shows the frame member which comprises the precast member of (a). It is a side view which shows the state which accumulated the precast member on the foundation of the field production yard. (A) is a top view which shows the frame member which comprises the precast member which concerns on 2nd Embodiment. (B) is the sectional view on the AA line of (a). (A) is a top view which shows the state which connected the some block member. (B) is a side view which shows the state which connected the some block member. It is a top view which shows the state which connects a some block member with a coupler. (A) is a top view which shows the precast member which concerns on 2nd Embodiment. (B) is the BB sectional drawing of (a). (C) is CC sectional view taken on the line of (a). (A) is a top view which shows the frame member which comprises the precast member which concerns on 3rd Embodiment. (B) is the DD sectional view taken on the line of (a).

  Hereinafter, the manufacturing method of the precast member concerning the present invention and the embodiment of a precast member are explained in detail, referring to drawings.

(First embodiment)
FIG. 1 is a perspective view showing an LNG tank (Liquefied natural Gas Tank) 1 constituted by a precast member 10 according to the present embodiment. FIG. 2 is a longitudinal sectional view of the LNG tank 1. In the present embodiment, the LNG tank 1 shows an example of a structure in which the liquid breakwater 4 is constituted by a precast member 10. The LNG tank 1 is a tank that stores LNG (liquefied natural gas), and is, for example, an above-ground tank.

  The outer shape of the LNG tank 1 is substantially cylindrical. As shown in FIG. 1 and FIG. 2, the LNG tank 1 includes an inner tank 2 that accommodates LNG, an outer tank 3 that is located outside the inner tank 2 and covers the top of the LNG tank 1, and an outer tank 3. A liquid breakwater 4 provided in an annular shape on the outside, a disk-shaped foundation slab 5 that supports the inner tank 2, the outer tank 3, and the liquid breakwater 4 below, and a plurality of foundation piles 6 that support the foundation slab 5. And.

  The inner tank 2 is made of, for example, a metal plate. That is, the inner tank 2 is constituted by a steel roof, a steel side wall, and a steel bottom plate. The outer tub 3 is also comprised, for example with the metal plate, and is comprised with the steel roof, the steel side wall (liner plate), and the steel bottom plate. A heat insulating material is provided between the inner tank 2 and the outer tank 3, and LNG is kept cold between the inner tank 2 and the outer tank 3. An annular steel side wall (liner plate) in the outer tub 3 is provided along the liquid barrier 4 inside the liquid barrier 4. The steel bottom slab is disposed on the foundation slab 5. The breakwater 4 is provided to prevent leakage of LNG to the outside. The plurality of foundation piles 6 are embedded in the ground, and the foundation slab 5 is supported by the plurality of foundation piles 6.

  The breakwater 4 is constituted by a plurality of block-shaped precast members 10, and the plurality of precast members 10 are arranged in parallel along the circumferential direction and the vertical direction of the LNG tank 1. That is, in the LNG tank 1, a plurality of precast members 10 are arranged in the circumferential direction of the LNG tank 1 and stacked in the vertical direction, and a joint portion is formed between the precast members 10 adjacent in the circumferential direction and the vertical direction. Thus, the breakwater 4 is constructed. Thus, the precast member 10 is a rectangular member that constitutes the wall of the LNG tank 1.

  FIG. 3A is a plan view showing the precast member 10, and FIG. 3B is a plan view showing the frame member 20 constituting the precast member 10. In FIGS. 3A and 3B, the concrete portion is shown in gray to clarify a hole 21a described later. As shown in FIG. 3A, the precast member 10 includes a concrete main body 11 formed in a rectangular flat plate shape, and a plurality of reinforcing bars 12 embedded in the main body 11 and projecting outward from the main body 11. It has.

  The main body 11 includes a rectangular flat plate surface 11 a, and the precast member 10 is installed so that the flat plate surface 11 a becomes the wall surface of the liquid barrier 4. A plurality of reinforcing bars 12 protrude from four surfaces orthogonal to the flat plate surface 11 a of the main body 11. The plurality of reinforcing bars 12 are embedded in the main body 11 and are arranged in a lattice shape in the main body 11.

  In the following description, the terms “thickness direction”, “width direction”, and “length direction” are used, but these terms are for convenience based on the illustrated state. In the following description, the thickness direction is the thickness direction of the main body 11 (the direction perpendicular to the paper surface of FIG. 3), the width direction is the direction in which the short side 11b of the flat plate surface 11a extends, and the length direction is the length of the main body 11. This is the direction in which the side 11c extends.

  The precast member 10 further includes a steel plate (plate-like member) 13, and this steel plate 13 is attached to the opposite side (lower side) of the flat plate surface 11a. The steel plate 13 is fixed to the main body 11 so that the outer edge of the flat plate surface 11a coincides, or has a larger area than the flat plate surface 11a, so that the outer edge of the steel plate 13 protrudes from the outer edge of the main body 11. It is fixed to the main body 11. Further, when the precast member 10 is installed, the steel plate 13 is joined to the steel plate 13 of the adjacent precast member 10.

  The precast member 10 configured as described above is formed by placing concrete C on the frame member 20. The frame member 20 includes a main body 21 made of concrete, and the main body 21 is formed in a rectangular frame shape by having a hole 21a. The hole 21a is formed at a position including the center of the flat plate surface 21b of the main body 21, for example, and has a rectangular shape on the flat plate surface 21b. The hole 21 a penetrates in the thickness direction of the main body 21. Moreover, the hole 21a has a size that does not impair the rigidity required when the frame member 20 is transported.

  The main body 21 has the above-described plurality of reinforcing bars 12 embedded therein, and the plurality of reinforcing bars 12 intersect each other inside the hole 21a. Specifically, the plurality of reinforcing bars 12 extending in the length direction and the plurality of reinforcing bars 12 extending in the width direction are orthogonal to each other inside the hole 21a, and the plurality of reinforcing bars 12 are arranged in a lattice pattern. Further, the steel plate 13 is attached to the main body 21 in advance so as to close the lower side of the hole 21a (the side opposite to the flat plate surface 21b). The steel plate 13 is attached in advance before being transported to the site in a factory or the like, not on the site.

  Concrete C is placed in the hole 21a of the main body 21 on site, and the precast member 10 is manufactured by placing the concrete C in the hole 21a. The frame member 20 is a member manufactured in advance in a factory, and the frame member 20 manufactured in the factory is transported to the site by a trailer or the like.

  Next, the manufacturing method which manufactures the precast member 10 from the frame member 20 conveyed to the spot is demonstrated. The manufacturing method described here is a manufacturing method for completing the rectangular precast member 10 on site.

  First, as shown in FIG. 4, a step of placing a base plate B that forms a flat portion in a site production yard Y provided on site is executed. This on-site production yard Y is provided, for example, at a position close to the site where the LNG tank 1 is constructed. The foundation version B placed in the on-site production yard Y is an RC foundation. The base plate B is formed so that the unevenness of the surface thereof is a predetermined value (for example, 1 cm) or less.

  Next, the process of carrying in the frame member 20 to the site and arranging the carried-in frame member 20 on the base plate B is executed. At this time, for example, as shown in the plan view of FIG. 3B, the frame member 20 is placed on the base plate B with the frame member 20 lying in advance so that the hole 21a of the frame member 20 faces upward. In this state, the reinforcing bars 12 are arranged in a lattice pattern in the holes 21 a of the frame member 20.

  After arranging the frame member 20 on the base plate B as described above, a step of placing concrete C inside the hole 21a is executed. At this time, the reinforcing bars 12 arranged in a lattice pattern inside the hole 21a are buried in the concrete C, and the precast member 10 as shown in FIG. 3A is manufactured. Specifically, curing is performed after placing concrete C in the hole 21a, and this curing is, for example, a wet curing for one week. In addition, in the manufacturing method of this embodiment, since a curing period can fully be ensured, steam curing is unnecessary.

  Also, as shown in FIG. 4, a vinyl sheet is laid on the precast member 10 that has been placed, and the placement of the frame member 20 on the vinyl sheet and the placement of concrete C into the hole 21a are repeated. The precast member 10 can be stacked. For example, the number of precast members 10 to be stacked can be approximately ten, and the maximum height of the precast members 10 to be stacked can be about 6 m. However, the number of steps and the height are appropriately changed according to the weight and thickness of the precast member 10.

  The precast member 10 manufactured as described above is lifted by, for example, a large crane, and the precast member 10 is installed. At this time, the precast member 10 is raised from a laid state, and the precast members 10 are installed, connected, and fixed. Thus, the plurality of precast members 10 are connected to complete the liquid bank 4 of the LNG tank 1. In addition, after connecting the some precast member 10, the tension | tensile_strength work of the whole breakwater 4 is performed by arrange | positioning PC steel wire to the sheath previously provided in the precast member 10. FIG.

  As described above, in the precast member 10 and the manufacturing method of the precast member 10 of the present embodiment, the frame member 20 is disposed on the base plate B so that the hole 21a faces upward, and then the concrete C is placed inside the hole 21a. Is cast, whereby the precast member 10 is manufactured. Therefore, the frame member 20 having the hole 21a can be manufactured in advance in a factory or the like, and the frame member 20 can be transported to the site. Therefore, the member to convey can be reduced in weight compared with the member which does not have a hole. That is, since the weight of the member placed on the trailer or the like can be reduced, the member can be efficiently transported to the site.

  Moreover, since the precast member 10 is manufactured by placing concrete C inside the hole 21a of the frame member 20 at the site, the precast member 10 larger than the conventional precast member can be completed at the site. Thus, by completing the larger-sized precast member 10 at the site, the number of precast members 10 at the site can be reduced. Therefore, the work period of the work of installing the plurality of precast members 10 can be shortened, and the workability can be improved. Thus, the member can be reduced in weight at the time of conveyance, the precast member 10 can be enlarged on the site, and the number of precast members 10 can be reduced, thereby improving the workability.

  In addition, a plurality of reinforcing bars 12 are embedded in the frame member 20 in advance, and before the step of placing concrete C, the plurality of reinforcing bars 12 intersect each other inside the hole 21a. Therefore, the rebar 12 is already embedded in the state where it is transported to the site. Therefore, since the precast member 10 can be completed only by placing the concrete C in the hole 21a at the site, the workability at the site can be further improved.

  Further, before the step of placing the concrete C, the steel plate 13 that closes the lower side of the hole 21a is attached to the frame member 20. Therefore, before the concrete C is placed, the lower side of the hole 21 a is closed by the steel plate 13. Therefore, when placing concrete C on site, the steel plate 13 can be used as a lower mold for closing the hole 21a, and the labor for installing the lower mold or the flat part can be saved. Therefore, the workability on site can be further enhanced.

  Furthermore, as described above, since the precast member 10 can be enlarged on site, the connection length when the precast member 10 is connected can be reduced. Accordingly, the amount of concrete filling and the amount of the water expansion seal in the connecting portion connecting between the precast member 10 and the adjacent precast member 10 can be reduced, so that the processing cost of the connecting portion can be greatly reduced. .

  Moreover, as above-mentioned, since this embodiment can fully ensure the placement curing period in the field, the strength of the precast member 10 can be expressed by a general curing method, and special curing equipment is provided. Can be made unnecessary. Furthermore, as described above, since the precast members 10 that have already been cast are stacked and the precast members 10 are manufactured, a large number of precast members 10 can be manufactured in a narrow production yard in a short period of time near the site. it can.

(Second Embodiment)
Next, the manufacturing method of the precast member 30 and the precast member 30 according to the second embodiment will be described. Below, the description which overlaps with the description mentioned above is abbreviate | omitted. FIG. 5A is a plan view showing the frame member 40 constituting the precast member 30, and FIG. 5B is a cross-sectional view taken along line AA of FIG. 5A.

  As shown in FIGS. 5A and 5B, the frame member 40 is formed in a vertically long rectangular shape as a whole, and a plurality of block members 41 and 42 are connected in a frame shape. It is formed. The block member 41 constitutes the short side of the frame member 40, and the block member 42 constitutes the long side of the frame member 40. The block members 41 and 42 are concrete members that are manufactured in advance in a factory or the like and transported to the site. The block members 41 and 42 are rectangular. A plurality of reinforcing bars 43 protrude from one surface 41b orthogonal to the surface 41a extending in the longitudinal direction of the block member 41, and a plurality of reinforcing bars are also formed from one surface 42b orthogonal to the surface 42a extending in the longitudinal direction of the block member 42. 44 protrudes.

  In addition, the shape and magnitude | size of the block member 41 and the block member 42 may mutually be the same, and may differ. However, if the shape and size of the block member 41 and the block member 42 are the same, one mold can be used at the time of manufacturing the block members 41 and 42, and the block members 41 and 42 can be efficiently used at a factory or the like. Is preferable because it can be manufactured.

  Below, the manufacturing method which manufactures the precast member 30 using these block members 41 and 42 is demonstrated.

  In this embodiment, the process of forming the frame member 40 is performed by connecting the block members 41 and 42 in a frame shape. First, the block members 41 and 42 are arranged on the base plate B of the on-site production yard Y so that the respective surfaces 41a and 42a extending in the longitudinal direction of the block members 41 and 42 face upward.

  Next, the two block members 42 are vertically arranged so that the two surfaces 42b are continuous with each other to form the long side of the frame member 40, and the long sides are arranged to face each other. And while connecting the upper ends of the said long side with the block member 41, the frame member 40 is formed by connecting the lower ends of the said long side with another block member 41. FIG. At this time, the reinforcing bar 43 protruding from the surface 41 b of the block member 41 and the reinforcing bar 44 protruding from the surface 42 b of the block member 42 protrude inside the frame member 40.

  The block members 41 and 42 are connected using, for example, a bolt box 45 shown in FIG. 6 or a coupler 46 shown in FIG. That is, as shown in FIGS. 6A, 6 </ b> B, and 7, the block member 41, the block member 42, and the two block members 42 are connected by the bolt box 45 or the coupler 46.

  The bolt box 45 is disposed on the surfaces 41 b and 42 b of the block members 41 and 42 constituting the inner side surface of the frame member 40, and on the surfaces 41 c and 42 c of the block members 41 and 42 constituting the outer side surface of the frame member 40. Also arranged. Each bolt box 45 is arranged so as not to be visible after the plurality of precast members 10 are connected. After the plurality of block members 41 and 42 are thus connected by the bolt box 45, the length and diagonal length of the outer edge of the frame member 40 are measured, and the length and diagonal length are within the required accuracy. Make sure.

  The coupler 46 is provided on any one of the joint surfaces 42d and 42e of the block member 42 constituting the frame member 40. For example, when the coupler 46 is provided on the joint surface 42d, the coupler 46 extends from the joint surface 42e of the block member 42. The protruding reinforcing bars 48 are inserted into the coupler 46, and then a solidifying agent is injected into the coupler 46 to connect the block members 42 to each other. The block member 41 and the block member 42 are similarly connected by the coupler 46. Thus, after connecting the plurality of block members 41, 42, the length and diagonal length of the outer edge of the frame member 40 are measured in the same manner as described above, and the length and diagonal length are within the required accuracy. Make sure.

  The process of forming the frame member 40 is completed by connecting the block members 41 and 42 with the bolt box 45 or the coupler 46 as described above. After the frame member 40 is formed in this way, reinforcement and sheath installation are performed in the hole portion of the frame member 40 constituted by the surface 41b of the block member 41 and the surface 42b of the block member 42. Then, as shown in FIGS. 5 and 8, the precast member 30 is manufactured by placing concrete C in the holes of the frame member 40. In addition, about the curing process in the process in which the precast member 30 is manufactured, and the process after precast member 30 manufacture, since it is the same as that of 1st Embodiment, description is abbreviate | omitted.

  As described above, the precast member 30 and the method for manufacturing the precast member 30 according to the second embodiment further include a step of forming the frame member 40 by connecting the plurality of block members 41 and 42 in a frame shape. Therefore, since the plurality of block members 41 and 42 are transported to the site, the transported members can be further reduced in weight. Further, since the frame member 40 is formed by connecting the plurality of block members 41 and 42 at the site, the precast member 30 having a larger size can be manufactured. Therefore, the number of precast members 30 at the site can be further reduced, which contributes to improvement in workability.

  Further, the block member 41 and the block member 42 are manufactured in advance at the factory, and the outer periphery and inner periphery of the frame member 40 are configured by the sides of the block members 41 and 42. Accuracy (flatness, diagonal length, width, length) can be easily ensured.

  Further, the ratio of the frame member 40 in the precast member 30 is smaller than the ratio of the concrete C in the precast member 30. Therefore, since the members (block members 41 and 42) manufactured in a factory or the like can be made smaller and lighter, the manufacturing cost can be significantly reduced compared with a conventional precast member having no hole. it can.

  Further, the combination of the block members 41 and 42 is not limited to the above, and can be changed as appropriate. That is, depending on how the block members 41 and 42 are combined, it is possible to complete a very large precast member 30 on-site as compared to the conventional precast member, for example, three times the size of the conventional precast member. The precast member 30 can be manufactured. Thus, when manufacturing the precast member 30 that is three times as large as the conventional one, the number of precast members 30 to be installed is reduced to 1/3, so that the installation period of the precast member 30 is shortened to about 1/3. Is possible.

(Third embodiment)
Next, a precast member and a manufacturing method thereof according to the third embodiment will be described with reference to FIG. Fig.9 (a) is a top view of the frame member 60 which comprises the precast member of 3rd Embodiment, FIG.9 (b) is the DD sectional view taken on the line of Fig.9 (a). In 3rd Embodiment, the structure of the frame member 60 differs from 2nd Embodiment, About another structure, it is the same as that of 2nd Embodiment. Therefore, below, the description which overlaps with 2nd Embodiment is abbreviate | omitted.

  As shown in FIG. 9A and FIG. 9B, the frame member 60 includes a first block member 61, a second block member 62, a first mold 63, and a second mold. It is formed by connecting the frame 64 to the frame shape. The first block member 61 and the second block member 62 are precast members that are manufactured in advance at a factory or the like and transported to the site.

  A plurality of reinforcing bars 65 protrude from a surface 61 b orthogonal to the surface 61 a extending in the longitudinal direction of the first block member 61, and a plurality of reinforcing bars 65 are also projected from a surface 62 b orthogonal to the surface 62 a extending in the longitudinal direction of the second block member 62. The reinforcing bar 66 protrudes. The shape and size of the first block member 61 are the same as the shape and size of the second block member 62.

  The first mold 63 has a rectangular plate shape with flat surfaces 63a and 63b on the front and back sides, and the second mold 64 also has flat surfaces 64a and 64b similar to the first mold 63. ing. The first mold 63 and the second mold 64 constitute the long side of the frame member 60, and the first block member 61 and the second block member 62 constitute the short side of the frame member 60. .

  Next, the manufacturing method which manufactures the precast member of 3rd Embodiment using the 1st block member 61, the 2nd block member 62, the 1st mold 63, and the 2nd mold 64 is demonstrated.

  First, the process of forming the frame member 60 is performed. Specifically, the first block member 61 and the second block member 62 are arranged on the base plate B of the on-site production yard Y so as to be parallel to each other. At this time, the position of the one end 61c of the first block member 61 and the position of the one end 62c of the second block member 62 are aligned with each other in the left-right direction in plan view, and the position of the other end 61d of the first block member 61 The position of the other end 62d of the second block member 62 is aligned.

  Then, the flat surface 63 b of the first mold 63 is fixed to one end 61 c of the first block member 61 and one end 62 c of the second block member 62. Further, the flat surface 64 b of the second formwork 64 is fixed to the other end 61 d of the first block member 61 and the other end 62 d of the second block member 62. By fixing the first and second molds 63 and 64, the one end 61c and the one end 62c are connected, and the other end 61d and the other end 62d are connected.

  As described above, the frame member 60 is formed by connecting the first block member 61, the second block member 62, the first mold frame 63, and the second mold frame 64, and the frame member 60 is formed. The process is complete. Then, after the step of forming the frame member 60 is completed, similarly to the second embodiment, the reinforcement is placed in the hole of the frame member 60 and the sheath is installed, and the concrete C is placed in the hole of the frame member 60. By doing so, the precast member of the third embodiment is manufactured. The mold 63 and the mold 64 are removed and diverted after the frame member 60 is completed.

  As described above, in the precast member and the manufacturing method thereof according to the third embodiment, the two opposite sides of the frame member 60 are the first block member 61 and the second block member 62, and the remaining two sides are the first mold. A frame 63 and a second mold 64 are obtained. Thus, the two sides of the frame member 60 are the first mold frame 63 and the second mold frame 64. Therefore, compared with the case where all the sides of the frame member are block members, the number of block members conveyed to the site can be reduced. Therefore, the weight of the conveyed member can be further reduced. Furthermore, since the number of block members to be conveyed can be reduced, the members can be conveyed more efficiently.

  Further, the first block member 61 and the second block member 62 are manufactured in advance at the factory, and the outer periphery of the short side of the frame member 40 is the first block member 61 and the second block member 62. It consists of sides. Therefore, the accuracy on the outer periphery of the short side of the frame member 40 can be easily ensured. Further, the outer periphery of the long side of the frame member 60 is constituted by the flat surface 63a of the first mold 63 and the flat surface 64a of the second mold 64, and the block member 61 and the block member are manufactured at both ends with high accuracy. Since the end faces 61c, 62c, 61d, and 62d of the 62 are fixed with bolts or the like, the accuracy on the outer periphery of the long side of the frame member 60 can be easily ensured.

  As mentioned above, although preferred embodiment which concerns on this invention was described, this invention is not limited to embodiment mentioned above. That is, it is easily recognized by those skilled in the art that various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

  For example, in the above-described embodiment, an example in which a plurality of precast members 10 are connected to complete the LNG tank 1 has been described. However, the precast member and the method for manufacturing the precast member according to the present invention can be applied to structures other than the LNG tank 1. For example, the present invention can be applied to a wall-like structure such as a retaining wall other than the LNG tank 1 or a column member, and when the present invention is applied to these structures, the same as in the above embodiment. The effect is obtained.

DESCRIPTION OF SYMBOLS 1 ... LNG tank (structure), 2 ... Inner tank, 3 ... Outer tank, 4 ... Liquid barrier, 5 ... Foundation slab, 6 ... Foundation pile, 10, 30 ... Precast member, 11, 21 ... Main body, 11a ... Flat surface, 11b ... short side, 11c ... long side, 12 ... reinforcing bar, 13 ... steel plate, 20, 40, 60 ... frame member, 21 ... main body, 21a ... hole, 21b ... flat plate surface, 41, 42 ... block member , 43, 44 ... rebar, 45 ... bolt box, 46 ... coupler, 48 ... rebar, 61 ... first block member, 61c ... one end, 61d ... the other end, 62 ... second block member, 62c ... one end, 62d ... the other end, 63 ... first formwork, 63a, 63b ... flat face, 64 ... second formwork, 64a, 64b ... flat face, 65,66 ... rebar, B ... foundation (flat part), C ... concrete, Y ... site production yard.

Claims (11)

A method of manufacturing a precast member that completes a rectangular precast member on-site,
A step of arranging the frame member so that the hole of the frame member formed in a rectangular frame shape faces upward;
Placing concrete inside the hole of the frame member;
The manufacturing method of the precast member provided with. In the field production yard provided in the field, further comprising a step of arranging a flat part for arranging the frame member so that the hole part faces upward.
The manufacturing method of the precast member of Claim 1. The step of arranging the frame member further includes a step of forming the frame member by connecting a plurality of block members in a frame shape.
The manufacturing method of the precast member of Claim 1 or 2. In the step of forming the frame member, the first block member and the second block member are arranged so as to face each other, and one end of the first block member and one end of the second block member are arranged. Are connected by a first mold, and the other end of the first block member and the other end of the second block member are connected by a second mold, thereby forming the frame member.
The manufacturing method of the precast member of Claim 3. A plurality of reinforcing bars are embedded in the frame member in advance,
Before the step of placing the concrete, the plurality of reinforcing bars intersect with each other inside the hole,
The manufacturing method of the precast member as described in any one of Claims 1-4. Before the step of placing the concrete, a plate-like member that closes the lower side of the hole is attached to the frame member.
The manufacturing method of the precast member as described in any one of Claims 1-5. A rectangular precast member constituting the wall of the structure,
A frame member having a hole and formed in a rectangular frame shape;
Concrete that is placed inside the hole in a state where the frame member is arranged so that the hole faces upward,
Precast member with The frame member is formed by connecting a plurality of block members conveyed to the site in a frame shape,
The precast member according to claim 7. The frame member includes the first block member and the second block member facing each other, and a first formwork connecting one end of the first block member and one end of the second block member. A second formwork connecting the other end of the first block member and the other end of the second block member,
The precast member according to claim 8. The frame member includes a plurality of reinforcing bars embedded so as to intersect with each other inside the hole,
The precast member according to any one of claims 7 to 9. The frame member includes a plate-like member that closes the lower side of the hole.
The precast member according to any one of claims 7 to 10.