JP2006057315A - Construction method for columnar structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance construction efficiency in the construction of a columnar structure made of reinforced concrete, and to keep a construction cost low. <P>SOLUTION: A given number of main reinforcements 34 and 36 are prearranged on the top surface of already constructed concrete 32; pedestals 100 are each mounted on the upper ends of the main reinforcements 34 and 36; a horizontal frame material 200 is installed on the pedestals 100; and the main reinforcements 34 and 36 are each temporarily fixed to the frame material 200. After that, a brace material 300 is arranged between a top surface of the concrete and the frame material 200; positioning of the frame material 200 is performed by adjusting the length of the brace material 300; and the rest of the main reinforcements 34, 36 and 38 are arranged by making the frame material 200 serve as a guide member. This dispenses with the conventional arrangement of a reinforcement supporting material in the state of protruding from scaffolding, and facilitates the arrangement of a hoop reinforcement etc. and the installation of a form, which are performed after the arrangement of the main reinforcement. Additionally, the construction cost is kept far lower than in the case of the installation of a built-up steel material for embedment by enabling the diversion of the frame material 200 and each of the pedestals 100. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for constructing a columnar structure made of reinforced concrete.

  In general, in a columnar structure in which a plurality of main reinforcing bars are arranged in the vicinity of a concrete surface, such as a pier made of reinforced concrete, a construction section having a predetermined height as described in, for example, “Patent Document 1”. Construction is performed by placing reinforcement and placing concrete every time.

  Conventionally, when a plurality of main reinforcing bars are arranged on the top surface of concrete that has been constructed in such a construction method, a plurality of reinforcing bar support members are projected in a horizontal direction from the scaffolds installed around the reinforcing bars to support each of the reinforcing bars. The upper end of each main reinforcing bar is fixed to the material. And after arrange | positioning a strip reinforcement etc. with respect to these several main reinforcing bars, a formwork is installed and concrete is laid.

Japanese Patent Laid-Open No. 10-82019

  However, in the conventional construction method described above, when the formwork is installed, the reinforcing bar support material becomes an obstacle, and it is necessary to remove it once. Moreover, after this formwork is installed, it is necessary to provide a reinforcing bar support material again to fix the upper end of the main reinforcing bar and adjust its position. In addition, the reinforcing bar support material may get in the way when arranging the reinforcing bars. For this reason, there is a problem that workability is very poor.

  On the other hand, if the assembly steel material for embedding is installed on the upper surface of the concrete that has already been constructed, and the upper end of each main reinforcing bar is fixed using this assembled steel material, the workability associated with the removal and installation of the reinforcing bar support material will be improved. The badness can be improved. However, when such a construction method is adopted, the assembly steel material is embedded by placing concrete, so that it cannot be diverted, and therefore, it costs a lot of construction. There's a problem.

  The present invention was made in view of such circumstances, and in a method for constructing a columnar structure made of reinforced concrete, a columnar structure that can increase the construction efficiency and keep the construction cost low. It aims to provide a construction method.

  The present invention has a configuration in which a predetermined number of main reinforcing bars are arranged in advance, a horizontal frame member having a predetermined shape is installed using these, and the remaining main reinforcing bars are arranged using the horizontal frame member as a guide member. Thus, the above-mentioned purpose is achieved.

That is, the columnar structure construction method according to the present invention is as follows.
In a method for constructing a columnar structure, a columnar structure made of reinforced concrete in which a plurality of main reinforcing bars are arranged in the vicinity of the concrete surface is constructed by arranging and placing concrete for each predetermined construction section.
A predetermined number of main reinforcing bars among the plurality of main reinforcing bars are arranged in advance on the top surface of the concrete that has already been constructed in the columnar structure, and a predetermined cradle is provided at the upper end of each of the preceding main reinforcing bars. Attaching process;
A step of installing a horizontal frame member of a predetermined shape on the plurality of cradles, and temporarily fixing each of the main reinforcing bars arranged in advance to the horizontal frame member;
A plurality of sets of brace materials are arranged between the top surface of the concrete that has been constructed and the horizontal frame material, and the positioning of the horizontal frame material is adjusted by adjusting the length of each set of brace materials. Process,
Placing the main reinforcing bars other than the previously arranged main reinforcing bars among the plurality of main reinforcing bars on the upper surface of the constructed concrete, using the horizontal frame material subjected to the positioning adjustment as a guide member. It is characterized by.

  The above-mentioned “columnar structure” is not particularly limited as long as it is made of reinforced concrete. For example, a rectangular shape, a polygonal shape, a circular shape, or the like can be adopted as the horizontal sectional shape. . Further, the “columnar structure” may have a hollow structure or a solid structure. Furthermore, the type of the “columnar structure” is not particularly limited, and for example, a bridge pier, a main tower, a tower, or the like can be adopted.

  As for the “predetermined number of main reinforcing bars”, it is attached to the upper end of these “predetermined number of main reinforcing bars” regarding how many main reinforcing bars to select from the “plural main reinforcing bars”. If it is in the range which can support a horizontal frame material via a cradle, it will not specifically limit.

  As long as each of the “cradles” is configured to support the horizontal frame member, the specific configuration such as the shape, size, and material thereof is not particularly limited. In addition, as a specific mode for attaching each of these “cradles” to “the upper end portion of each main reinforcing bar arranged in advance”, it is attached to the upper end portion of each main reinforcing bar that is actually in a pre-arranged state. Alternatively, it may be attached in advance to the upper end of each main reinforcing bar before being placed in advance. In short, each cradle is attached to the upper end of each main reinforcing bar when installing the horizontal frame material. It only has to be in the state.

  The “horizontal frame member” may be constituted by a single member or may be constituted by assembling a plurality of members. Further, the shape of the “horizontal frame member” is not limited to a specific shape as long as it can function as a guide member when a plurality of main reinforcing bars are arranged. Further, the “horizontal frame member” may be configured to guide a plurality of main reinforcing bars on its inner peripheral side, or configured to guide a plurality of main reinforcing bars on its outer peripheral side. It may be a thing, and it may be constituted so that a plurality of main reinforcing bars may be guided on both the inner circumference side and the outer circumference side. Further, the “horizontal frame material” may be configured as a single frame or may be configured as a multiple frame.

  The above-mentioned “multiple sets of brace materials” are specific to the number and arrangement of the braces as long as the length of each set of brace materials can be adjusted to adjust the positioning of the horizontal frame material. The specific configuration is not particularly limited. In addition, a specific method for adjusting the length of each set of brace members is not particularly limited, and for example, a turnbuckle or a lever block can be used.

  As shown in the above configuration, the columnar structure construction method according to the present invention includes a predetermined number of main reinforcing bars arranged on the upper surface of the finished concrete, and a cradle attached to the upper end of each main reinforcing bar. After installing horizontal frame members on multiple cradles, temporarily fix each of the above-mentioned main reinforcing bars to the horizontal frame members, and then set multiple sets between the top surface of the concrete that has been installed and the horizontal frame members. By adjusting the length of each pair of brace materials, the horizontal frame material is positioned and adjusted, and the remaining main reinforcing bars are placed using this horizontal frame material as a guide member. Therefore, the following effects can be obtained.

  In other words, unlike the conventional construction method described above, it is not necessary to arrange the reinforcing bar support members so as to protrude from the scaffold. Therefore, it is possible to easily perform the arrangement of the band reinforcing bars and the formwork performed after the main reinforcing bars are arranged. Thus, workability can be improved. Moreover, since the horizontal frame material and each cradle can also be diverted to the construction in the next construction section, compared to the case where the assembly steel material for embedding is installed on the upper surface of the concrete already constructed, Construction costs can be greatly reduced.

  Thus, according to this invention, in the method of constructing the columnar structure made of reinforced concrete, construction efficiency can be increased and construction cost can be suppressed at a low cost.

  In the above configuration, a plurality of positioning recesses for positioning the plurality of main reinforcing bars are formed on the circumferential surface of the horizontal frame member at predetermined intervals in the circumferential direction of the horizontal frame member. And the function as a guide member of a horizontal frame material can be improved, and construction efficiency can be improved further by this.

  Moreover, in the said structure, if the assembly steel material which assembles several steel materials is used as a horizontal frame material, it will become possible to change the shape of a horizontal frame material suitably. Therefore, even when constructing a columnar structure whose horizontal cross-sectional shape changes depending on the height position, the horizontal frame material can be easily diverted.

  In this case, as each steel material constituting the assembly steel material, a composite steel material in which a steel plate is welded to a shape steel is used, and if the plurality of positioning recesses are formed on the steel plate, the assembly steel material is obtained. It is possible to easily form the positioning recess while ensuring sufficient strength.

  In this case, if a movable steel material having a predetermined number of positioning recesses is attached to a predetermined position of the assembled steel material, a columnar structure whose horizontal cross-sectional shape changes depending on the height position is constructed. In this case, by moving the movable steel material sequentially according to the movement of the construction section, regardless of the positions of the plurality of positioning recesses formed on each steel material constituting the assembled steel material, The attachment position of the upper end portion to the horizontal frame material can be set to an intended position by a positioning recess formed in the movable steel material.

  In the said structure, if the member which has a U-shaped recessed part for engaging with each main reinforcing bar is used as each receiving stand, attachment of each receiving stand with respect to each main reinforcing bar can be performed easily.

  Further, in the above configuration, a deformed reinforcing bar having a threaded portion formed on the outer peripheral surface is used as each main reinforcing bar, and a pair of lock nuts are mounted in advance on each of the main reinforcing bars arranged in advance. If the cradle is attached to each main reinforcing bar by sandwiching the cradle with the cradle, the cradle can be easily attached and detached, which can further improve the construction efficiency and divert each cradle. Can be facilitated.

  Furthermore, in the above configuration, if a bracing material constructed by adding a plurality of steel materials is used as the brace material for each set, when the concrete is placed, the upper surface of the applied concrete is moved upward. The projecting steel material can be removed and used for diversion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing a bridge 10 including a pier 20 that is a target of a method for constructing a columnar structure according to an embodiment of the present invention, in which FIG. 1 (a) is a side view and FIG. 1 (b). Is a view in the direction of the arrow b.

  As shown in the figure, this bridge 10 is an extradosed bridge, and its pier 20 is constructed as a columnar structure having a height of about 100 m extending from the upper surface of a large diameter deep foundation 22 to a bridge girder 24. A pair of main towers 26 are constructed at the upper end portion of the bridge pier 20 so as to sandwich the bridge girder 24, and a plurality of diagonal members 28 are arranged in tension between the main towers 26 and the bridge girder 24. ing.

  The pier 20 is a reinforced concrete structure having a hollow structure with a rectangular cross section, and is formed with a constant width of about 12 m in a vertical plane perpendicular to the bridge axis, but in a vertical plane including the bridge axis. Is tapered so that the width gradually decreases from 12 m to 5 m upward.

  FIG. 2 is a detailed cross-sectional view taken along the line II-II in FIG. 1 (b), showing the bar arrangement structure inside the concrete of the pier 20.

  As shown in the figure, the pier 20 has a rectangular box-shaped cross section formed of a pair of vertical wall portions 20A and a pair of inclined wall portions 20B. The width of each vertical wall portion 20A and each inclined wall portion 20B is set to a value of about 1.2 m. A plurality of main reinforcing bars 34 and 36 are arranged at predetermined intervals in the circumferential direction in the vicinity of the outer peripheral surface 32a and the inner peripheral surface 32b of the concrete 32 in the pier 20. At that time, the cover thickness of the concrete 32 is set to a value of about 150 mm. In addition, a plurality of main reinforcing bars 38 are arranged in the vicinity of the outer peripheral surface 32a of each inclined wall portion 20B so as to be positioned about 150 mm inside the main reinforcing bar 34.

  These three types of main reinforcing bars 34, 36, and 38 are all formed of deformed reinforcing bars having a length of about 12 m, and screw portions 34a, 36a, and 38a (see FIG. 19) are formed on the outer peripheral surface thereof. . At this time, large-diameter deformed reinforcing bars (for example, D51) are used as the main reinforcing bars 34, 38, while slightly large-diameter deformed reinforcing bars (for example, D38) are used as the main reinforcing bars 36. The main reinforcing bars 34 are arranged at a relatively narrow pitch of about 150 mm, while the main reinforcing bars 36 and 38 are arranged at a relatively wide pitch of about 300 mm.

  In the pier 20, a plurality of band reinforcing bars 40 are arranged so as to surround the main reinforcing bar 34, and a plurality of band reinforcing bars 42 are arranged along the main reinforcing bar 36 on the inner peripheral side of the main reinforcing bar 36. In addition, a plurality of width-retaining reinforcing bars 44 are disposed so as to straddle the band reinforcing bars 40 and 42, and a distribution reinforcing bar 46 is disposed along the band reinforcing bars 40 and 42.

  The pier 20 is constructed by performing reinforcement and concrete placement for each construction section having a predetermined height (specifically, about 6 m).

  Next, the outline | summary of the construction method of the columnar structure which concerns on this embodiment is demonstrated.

  3 to 10 are process diagrams showing a construction procedure in one construction section located substantially in the center of the pier 20 as a sectional view taken along the line III-III in FIG.

  In FIG. 3, a portion indicated by a two-dot chain line indicates a target construction section.

  First, as shown in the figure, a predetermined number of main reinforcing bars 34, 36 among the plurality of main reinforcing bars 34, 36, 38 are arranged in advance on the upper surface of the concrete 32 that has been constructed in the pier 20 and these preceding A predetermined cradle 100 is attached to the upper end of each of the arranged main reinforcing bars 34 and 36.

  At that time, as the predetermined number of main rebars 34 and 36, there are eight pieces located in the approximate center of each vertical wall portion 20A and each inclined wall portion 20B and in the vicinity of the corner portion of each inclined wall portion 20B with each vertical wall portion 20A. Main reinforcing bars 34 and four main reinforcing bars 36 located at the approximate center of each vertical wall portion 20A and each inclined wall portion 20B are selected. Further, the main reinforcing bars 34 and 36 arranged in advance are connected to the main reinforcing bars 34 and 36 protruding upward from the upper surface of the finished concrete 32 by using a coupler 50.

  In the figure, for convenience of explanation, the number of main reinforcing bars 34 is reduced to about half, and the main reinforcing bars 36 are two main reinforcing bars arranged in advance on each vertical wall portion 20A. Only 36 is shown, and the description of the main reinforcing bar 38 is omitted. These points are the same in FIGS.

  Next, as shown in FIG. 4, a horizontal frame member 200 having a predetermined shape is installed on twelve cradles 100 attached to the upper ends of the eight main reinforcing bars 34 and the four main reinforcing bars 36. The main reinforcing bars 34 and 36 arranged in advance are temporarily fixed to the horizontal frame member 200.

  Next, as shown in FIG. 5, a plurality of sets of brace members 300 are arranged between the top surface of the concrete 32 that has been subjected to construction and the horizontal frame member 200, and the lengths of these sets of brace members 300 are adjusted. Thus, the positioning adjustment of the horizontal frame member 200 is performed. At that time, as each set of brace material 300, a connection type brace material constituted by adding a plurality of steel materials 302 is used, and the length is adjusted by interposing a turnbuckle 304 at the upper end portion thereof.

  In the figure, for convenience of explanation, only one set of brace members 300 arranged on the inclined wall portion 20B is shown, but actually, one set of brace members 300 is also provided on each vertical wall portion 20A. Is placed. This also applies to FIGS.

  Next, as shown in FIG. 6, the eight main reinforcing bars 34 and the four main reinforcing bars arranged in advance on the upper surface of the concrete 32 that has been subjected to construction, using the horizontal frame member 200 that has been subjected to the positioning adjustment as a guide member. Main reinforcing bars 34, 36, 38 other than 36 are arranged. The main reinforcing bars 34, 36, and 38 are also connected to the main reinforcing bars 34, 36, and 38 that protrude upward from the upper surface of the concrete 32 that has been constructed by using the coupler 50.

  At this stage, the position of the horizontal frame member 200 is confirmed and adjusted again.

  Next, as shown in FIG. 7, a plurality of band reinforcing bars 42 are arranged, a plurality of width-retaining reinforcing bars (not shown) are arranged, and the bar arrangement for one construction section is completed.

  Next, as shown in FIG. 8, the mold 400 is installed on the outer peripheral surface 32a and the inner peripheral surface 32b of the concrete 32 that has been subjected to construction.

  Next, as shown in FIG. 9, concrete is placed in the mold 400. At this time, the main reinforcing bars 34, 36, and 38 are embedded in the concrete 32 in which the substantially lower half is placed, and the brace material 300 of each set also has the substantially lower half in the concrete 32. It will be buried.

  Next, as shown in FIG. 10, the mold 400 is removed, and the horizontal frame member 200 and each cradle 100 are removed. At that time, in each pair of brace members 300, the steel member 302 and the turnbuckle 304 that were not embedded in the concrete 32 are also removed.

  Then, in the next construction section (the portion indicated by the two-dot chain line in the figure), the reinforcement arrangement and the concrete placement are performed using a plurality of main reinforcing bars 34, 36, 38 protruding upward from the upper surface of the placed concrete 32. The bar arrangement and concrete placement in the next construction section are performed according to the procedures shown in FIGS.

  Next, the detail of the construction method of the columnar structure according to the present embodiment will be described.

  11 is a plan view showing the construction stage of FIG. 4, FIG. 12 is a detailed view of the XII portion of FIG. 11, and FIG. 13 is a detailed view of the XIII portion of FIG. FIG. 14 is a detailed view of the XIV part of FIG. 4 showing a state when the horizontal frame member 200 is attached to the upper ends of the main reinforcing bars 34 and 36 arranged in advance.

  As shown in FIG. 11, the horizontal frame member 200 is configured as a multiple frame in which an outer frame 202, an inner frame 204, and a pair of additional frames 206 are connected via square steel pipes 208 at four locations. .

  The outer frame 202 is configured as a rectangular frame formed along the arrangement shape of the plurality of main reinforcing bars 34, and the main reinforcing bars 34 are positioned from the outer peripheral side. In order to realize this, a plurality of positioning recesses 202 a for positioning the plurality of main reinforcing bars 34 are provided on the inner peripheral surface of the outer frame 202 at intervals of about 150 mm in the circumferential direction of the outer frame 202. Is formed.

  The outer frame 202 is composed of an assembled steel material obtained by assembling two steel materials 210 and two steel materials 212. At this time, the steel materials 210 and 212 are assembled in a state where the two steel materials 210 positioned on the vertical wall portion 20A are arranged on the two steel materials 212 positioned on the inclined wall portion 20B. It is done by connecting and fixing through a clamp that does not.

  Each steel material 210 located in the vertical wall portion 20A is configured as a composite steel material in which a steel plate 210B is welded to the lower surface of the H-shaped steel 210A, and each steel material 212 located in the inclined wall portion 20B is an H-shape. A steel plate 212B is welded to the lower surface of the steel 212A to form a composite steel material. At that time, in each steel material 210 located on the vertical wall portion 20A, a movable steel material 216 (which will be described later) is attached to both ends of the upper surface of the H-shaped steel 210A. In the outer frame 202, the plurality of positioning recesses 202a are formed on the end surfaces of the steel plates 210B and 212B and the movable steel material 216.

  A pair of perforated brackets 230 for suspending the horizontal frame member 200 are welded to the upper surfaces of the steel members 210 and 212 of the outer frame 202 one by one.

  The inner frame 204 is configured as a rectangular frame formed along the arrangement shape of the plurality of main reinforcing bars 36, and these main reinforcing bars 36 are positioned from the inner peripheral side. In order to realize this, a plurality of positioning recesses 204 a for positioning the plurality of main reinforcing bars 36 are formed on the outer peripheral surface of the inner frame 204 at intervals of about 300 mm in the circumferential direction of the inner frame 204. Has been.

  The inner frame 204 is composed of an assembled steel material obtained by assembling two steel materials 218 and two steel materials 220. At this time, the steel materials 218 and 220 are assembled in a state where the two steel materials 218 located on the vertical wall portion 20A are disposed below the two steel materials 220 located on the inclined wall portion 20B. It is done by connecting and fixing through a clamp that does not. Each of these steel materials 218 and 220 is made of angle steel.

  Each additional frame 206 is composed of a single angle steel, and positions a plurality of main reinforcing bars 38 arranged in a straight line from the inner peripheral side. In order to realize this, a plurality of positioning recesses 206a for positioning the plurality of main reinforcing bars 38 are formed on the end face on the outer peripheral side of the additional frame 206 at intervals of about 300 mm.

  As shown in FIG. 12, the movable steel material 216 attached to the steel material 210 of the outer frame 202 has a small angle steel 216B welded to both ends of an angle steel 216A extending along the steel material 210. The angle iron 216B is fixed to the H-shaped steel 210A of the steel material 210 via a clamp (not shown). Then, by moving the movable steel material 216 along the steel material 210, a part of the plurality of positioning recesses 202a can be displaced.

  The necessity of using such a movable steel material 216 will be described as follows.

  That is, as shown in FIG. 15 which is an XV direction arrow view of FIG. 4, the main reinforcing bars 34, 36 and 38 (however, the main reinforcing bar 38 is not shown) arranged on the inclined wall portion 20 </ b> B are In this case, the main reinforcing bars 34 arranged on the vertical wall portion 20A are also positioned at both end portions of the vertical wall portion 20A. The several main reinforcing bars 34 are arranged so as to extend in a direction inclined by the inclination angle of the inclined wall portion 20B with respect to the vertical direction. For this reason, the attachment position to the horizontal frame material 200 of the upper end part of these several main reinforcing bars 34 will be displaced toward the center as the construction section moves upward. Therefore, when all of the plurality of positioning recesses 202a are formed at an equal pitch, the mounting positions of these several main reinforcing bars 34 are shifted from the intended positions.

  Therefore, as described above, the movable steel material 216 is attached to both ends of the steel material 210 located on the vertical wall portion 20A in the outer frame 202, and the movable steel material 216 is centered along the steel material 210 as the construction section moves upward. By moving it closer, the upper ends of these several main reinforcing bars 34 can be attached to the horizontal frame member 200 at the intended position.

  When the movable steel material 216 is moved toward the center along the steel material 210 in this way, a plurality of positioning recesses 202a formed in the movable steel material 216 and a plurality of positioning materials formed in the steel plate 210B of the steel material 210 are obtained. The recessed part 202a will be arrange | positioned overlapping on the up-and-down both sides of H-section steel 210A. For this reason, as shown in FIG. 12, at both ends of the steel material 210, the steel plate 210B is cut out from the H-section steel 210A.

  Further, as the construction section moves upward, the steel material 210 positioned on the vertical wall portion 20A greatly protrudes from the steel material 212 positioned on the inclined wall portion 20B to the outer peripheral side. Should be excised sequentially. Similarly, both ends of the steel material 218 located on the vertical wall portion 20A in the inner frame 204 are sequentially cut as the construction section moves upward.

  As shown in FIGS. 13 and 14, each cradle 100 is configured as a composite steel material having a U-shaped recess 100 a for engaging with each main reinforcing bar 34, 36. That is, the cradle 100 includes a cradle body 100A having the U-shaped recess 100a at the front end, a spacer block 100B made of H-shaped steel welded to the upper surface of the body portion 100A, and the spacer block 100B. It consists of a vertical plate 100C made of a steel plate welded to the rear end face.

  The cradle 100 is attached to the main rebars 34 and 36 by attaching a pair of lock nuts 52 to the main rebars 34 and 36 in advance, and the pair of lock nuts 52 is used to mount the cradle body 100A. This is done by sandwiching from the top and bottom sides. At that time, a washer 54 is interposed on the upper surface of the lock nut 52 arranged on the lower side of the cradle 100 so that the cradle 100 is reliably supported.

  In the cradle body 100A of each cradle 100, a pair of small holes are formed in both side walls of the U-shaped recess 100a, and a nut 104 is welded to one of them. Then, with these cradles 100 engaged with the main reinforcing bars 34 and 36 in the U-shaped recesses 100a, the bolts 102 are inserted into the pair of small holes and tightened to the nuts 104, The main reinforcing bars 34 and 36 are prevented from being inadvertently detached from the U-shaped recess 100a.

  Each cradle 100 supports the horizontal frame member 200 on the upper surface of the spacer block 100B. At that time, the steel material 212 of the outer frame 202, the steel material 220 of the inner frame 204, the steel material 210 of the outer frame 202, and the steel material 218 of the inner frame 204 are different in height, and accordingly, the spacer block 100B. Since it is necessary to set the height of the upper surface to a different position, the mounting height of each cradle 100 is adjusted in advance according to the steel material to be supported by adjusting the lock nut 52.

  The mounting of the cradle 100 to the main reinforcing bars 34 and 36 may be performed using a scaffold after the main reinforcing bars 34 and 36 are arranged, or the main reinforcing bars 34 and 36 may be used. Before placing the main reinforcing bars 34 and 36, the cradle 100 is mounted in advance, and after the main reinforcing bars 34 and 36 are placed, only the height position and orientation of the cradle 100 are adjusted. May be performed. Further, the lock nut 52 and the washer 54 may be attached to the main reinforcing bars 34 and 36 at any time before and after the main reinforcing bars 34 and 36 are arranged. Furthermore, the lock nut 52 and the washer 54 may be removed together with the cradle 100 when the construction for one construction section is completed, or may be buried in the concrete 32 without being removed.

  In each cradle 100, an opening 100b is formed above the vertical plate 100C. Then, as shown in FIG. 13, with the outer frame 202 placed on the upper surface of the spacer block 100B, a steel wire 106 is inserted into the opening 100b of the vertical plate 100C, and the steel wire 106 is inserted into the outer frame 202. The main reinforcing bar 34 is temporarily fixed to the outer frame 202 by being wound around the main reinforcing bar 34 so as to be pressed from above. The temporary fixing of the main reinforcing bar 36 to the inner frame 204 is similarly performed.

  16 is a detailed view of the XVI portion of FIG. 5, and FIG. 17 is a detailed view of the XVII portion of FIG.

  As shown in FIG. 16, the plurality of steel members 302 constituting each set of brace members 300 are formed in an elongated plate shape, and are connected to each other by bolts 306 at each end thereof. And each set of brace material 300 is connected to an anchor 60 installed in advance on the upper surface of the finished concrete 32 by bolting at its lower end. Further, as shown in FIG. 17, these sets of brace members 300 are connected to a bracket 222 welded to the lower surface of the horizontal frame member 200 by bolting at the upper end portions thereof.

  Note that the brace material 300 disposed on the inclined wall portion 20B moves toward the center as the construction section moves upward, so the connection position of the upper end portion to the bracket 222 also moves toward the center. It is necessary to make it. Therefore, by arranging a plurality of brackets 222 at predetermined intervals, the brace material 300 can be connected and fixed at predetermined positions. Alternatively, instead of doing this, the bracket 222 may be fixed to the movable steel material 216 and moved toward the center along with the movement of the movable steel material 216.

  18 is a plan view showing the construction stage of FIG. 6, FIG. 19 is a detailed view of the IXX portion of FIG. 18, and FIG. 20 is a detailed view of the XX portion of FIG.

  As shown in FIGS. 18 and 19, in this construction stage, all the main reinforcing bars 34, 36, and 38 are arranged using the horizontal frame member 200 as a guide member, and the outer frame 202, the inner frame 204, and the additional frame 206 are arranged. Are positioned in the positioning recesses 202a, 204a and 206a.

  At that time, as shown in FIG. 20, a steel wire 224 is wound around each main reinforcing bar 34 so as to be surely positioned and fixed to the steel material 212 of the outer frame 202. In order to realize this, a pair of small holes 202b through which the steel wire 224 is inserted are formed in the steel plate 212B of the steel material 212 of the outer frame 202 in the vicinity of both sides of each positioning recess 202a. In addition, the same small hole is formed in the steel plate 210B in the steel material 210 of the outer frame 202, and the same small hole is formed in the steel materials 218 and 220 of the inner frame 204 and each additional frame 206. As a result, all the main reinforcing bars 34, 36, 38 are reliably positioned and fixed at the positions of the positioning recesses 202a, 204a, 206a with respect to the outer frame 202, the inner frame 204, and the additional frames 206. To.

  As described above in detail, the columnar structure construction method according to the present embodiment places a predetermined number of main reinforcing bars 34 and 36 in advance on the upper surface of the concrete 32 that has been subjected to construction, and the upper ends of these main reinforcing bars 34 and 36. After the cradle 100 is attached to the part and the horizontal frame member 200 is installed on the cradle 100, each of the main reinforcing bars 34 and 36 arranged in advance on the horizontal frame member 200 is temporarily fixed, Positioning adjustment of the horizontal frame material 200 is performed by arranging a plurality of sets of brace materials 300 between the top surface of the concrete 32 after construction and the horizontal frame material 200 and adjusting the length of each set of the brace materials 300. Since the remaining main reinforcing bars 34, 36, and 38 are arranged using the horizontal frame member 200 as a guide member, the following operational effects can be obtained.

  In other words, unlike the conventional construction method, it is not necessary to arrange the reinforcing bar support members so as to protrude from the scaffold, so that the band reinforcing bars 40, 42, the width-retaining reinforcing bars 44 and the arrangement performed after the main reinforcing bars 34, 36, 38 are arranged. The arrangement of the reinforcing bars 46 and the installation of the formwork 400 can be easily performed, and thereby the workability can be improved. Moreover, since the horizontal frame member 200 and each cradle 100 can be diverted to the construction in the next construction section, it is compared with the case where the assembly steel material for embedding is installed on the upper surface of the concrete 32 already constructed. Thus, the construction cost can be greatly reduced.

  As described above, according to the present embodiment, it is possible to increase the construction efficiency when constructing the pier 20 made of reinforced concrete and to suppress the construction cost at a low cost.

  In particular, in the present embodiment, since the main reinforcing bars 34 and 36 arranged in advance are composed of large-diameter rebars and slightly large-diameter rebars, the number of the pre-arranged pieces is as small as 12 pieces. Regardless, the support strength for the horizontal frame member 200 can be sufficiently secured.

  In the present embodiment, a plurality of positioning recesses 202a, 204a, 206a for positioning the plurality of main reinforcing bars 34, 36, 38 are provided on the peripheral surface of the horizontal frame member 200 at predetermined intervals in the circumferential direction. Therefore, the function of the horizontal frame member 200 as a guide member can be enhanced, thereby further improving the construction efficiency.

  In the present embodiment, a multi-frame having an outer frame 202, an inner frame 204 and a pair of additional frames 206 is used as the horizontal frame member 200, but two steel members 210 and two steel frames 210 are used as the outer frame 202. Since an assembled steel material obtained by assembling the steel material 212 is used, and an assembled steel material obtained by assembling the two steel materials 218 and the two steel materials 220 is used as the inner frame 204, the horizontal frame material 200 The shape can be easily changed as appropriate. Therefore, even when building a columnar structure whose horizontal cross-sectional shape changes depending on the height position, such as the pier 20 that is the object of the construction method according to the present embodiment, the horizontal frame member 200 can be easily diverted. it can.

  At this time, in this embodiment, as each steel material 210, 212 constituting the outer frame 202, a composite steel material in which the steel plates 210B, 212B are welded to the H-shaped steel 210A, 212A is used, and the steel plates 210B, 212B are used. On the other hand, since the plurality of positioning recesses 202a are formed, the positioning recesses 202a can be easily formed after sufficiently securing the strength of the outer frame 202.

  Furthermore, in this embodiment, the movable steel material 216 in which several positioning recesses 202a are formed is disposed at both ends of the steel material 210 of the outer frame 202 positioned on the vertical wall portion 20A. As the construction section moves upward, it is moved toward the center along the steel material 210. Therefore, several main reinforcing bars extending in the inclined direction along the inclined wall portion 20B at both end portions of the vertical wall portion 20A. 34 can also be attached to the horizontal frame member 200 at its upper end at the desired position.

  In the present embodiment, as each cradle 100, a member having a U-shaped recess 100a for engaging with each main reinforcing bar 34, 36, 38 is used, so each main reinforcing bar 34, 36, Each cradle 100 can be easily attached to 38.

  Moreover, in this embodiment, although the deformed reinforcing bar in which the screw portions 34a, 36a, 38a are formed on the outer peripheral surface is used as the main reinforcing bars 34, 36, 38, the main reinforcing bars 34, A pair of lock nuts 52 is attached to 36 in advance, and the cradle 100 is sandwiched between the pair of lock nuts 52 so that the cradle 100 is attached to the main reinforcing bars 34 and 36. Therefore, the cradle 100 can be easily attached and detached, whereby the construction efficiency can be further increased and the diversion of each cradle 100 can be facilitated.

  Furthermore, in this embodiment, since the connection type brace material comprised by adding the some steel material 302 is used as each set of brace material 300, when concrete placement is performed, the upper surface of the concrete 32 already constructed It is possible to remove the steel material 302 protruding upward from the steel plate and divert it. At this time, each set of brace members 300 has a structure in which a turnbuckle 304 for adjusting the length is interposed at the upper end portion of the connecting brace member. Can be diverted.

  By the way, the specific numerical values shown as the specifications in the above embodiment are merely examples, and it goes without saying that other numerical values may be adopted.

  Moreover, in the said embodiment, the composite steel material is used as each steel material 210,212 which comprises the outer frame 202, and the recessed part 202a for positioning is formed in the steel plates 210B, 212B fixed to the H-shaped steel 210A, 212A. On the other hand, as each steel material 218, 220 and each additional frame 206 constituting the inner frame 204, angle steel is used, and the positioning recesses 204a, 206a are directly formed in each angle steel, As for each steel material 218, 220 and each additional frame 206, a steel plate may be fixed to the angle steel, and the positioning recesses 204a, 206a may be formed in each steel plate.

  Furthermore, in the said embodiment, it is located in the corner part vicinity with each vertical wall part 20A in each vertical wall part 20A and each vertical wall part 20B as a main reinforcing bar arrange | positioned ahead and each inclination wall part 20B. Although the eight main reinforcing bars 34 and the four main reinforcing bars 36 positioned at the approximate center of each vertical wall portion 20A and each inclined wall portion 20B are selected, the necessity of the supporting strength for the horizontal frame member 200 is required. Depending on the above, the number and arrangement of the selection may be changed as appropriate.

  In the above embodiment, the height of one construction section is set to a height corresponding to half the length of each main reinforcing bar 34, 36, 38, and the same construction is performed with two construction sections as one unit. However, it is of course possible to set the height of one construction section to a height corresponding to the total length of each main reinforcing bar 34, 36, 38 and repeat the construction shown in FIGS. Is possible.

It is a figure which shows the bridge provided with the pier used as the object of the construction method of the columnar structure which concerns on one Embodiment of this invention, Comprising: The figure (a) is a side view, The figure (b) is the b direction arrow view. Figure Detailed cross-sectional view taken along line II-II in Fig. 1 (b) showing the reinforcement structure inside the concrete of the pier. Process diagram showing the construction procedure in one construction section located at the approximate center of the above pier as a cross-sectional view taken along line III-III in Fig. 2 (Part 1) Process diagram similar to FIG. 3 showing the construction procedure (No. 2) Process diagram similar to FIG. 3 showing the construction procedure (No. 3) Process diagram similar to FIG. 3 showing the construction procedure (No. 4) Process diagram similar to FIG. 3 showing the construction procedure (No. 5) Process diagram similar to FIG. 3 showing the construction procedure (No. 6) Process diagram similar to FIG. 3 showing the construction procedure (No. 7) Process drawing similar to FIG. 3 showing the construction procedure (No. 8) Plan view showing the construction stage of FIG. Detailed view of section XII in Fig. 11 Detailed view of part XIII in Fig. 12 Detailed view of the XIV section in Fig. 4 showing the situation when the horizontal frame is attached to the upper end of the main reinforcing bar placed in advance XV direction arrow view of FIG. Detailed view of XVI section in Fig. 5 Detailed view of XVII section in Fig. 5 Plan view showing the construction stage of FIG. Detailed view of IXX section in Fig. 18 Detailed view of part XX in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bridge 20 Pier 20A Vertical wall part 20B Inclined wall part 22 Large diameter deep foundation 24 Bridge girder 26 Main tower 28 Diagonal material 32 Concrete 32a Outer peripheral surface 32b Inner peripheral surface 34, 36, 38 Main reinforcement 34a, 36a, 38a Thread part 40, 42 Reinforcing Bar Reinforcing Bar 44, Width Reinforcing Bar Reinforcement 46 Power Distribution Reinforcing Bar 50 Coupler 52 Lock Nut 54 Washer 60 Anchor 100 Receiving Base 100A Receiving Body Main Body 100B Spacer Block 100C Vertical Plate 100a U-Shaped Recess 100b Opening 102 Bolt 104 Nut 106 Steel Wire 200 Horizontal frame material 202 Outer frame 202a, 204a, 206a Positioning recess 202b Small hole 204 Inner frame 206 Additional frame 208 Square steel pipe 210, 212, 218, 220 Steel material 210A, 212A H section steel 210B, 212B Steel plate 216 Movable steel material 16A, 216B angle iron 222 bracket 224 steel wire 230 apertured bracket 300 brace 302 steel 304 Turnbuckle 306 volts 400 Formwork

Claims (8)

In a method for constructing a columnar structure, a columnar structure made of reinforced concrete in which a plurality of main reinforcing bars are arranged in the vicinity of the concrete surface is constructed by arranging and placing concrete for each predetermined construction section.
A predetermined number of main reinforcing bars among the plurality of main reinforcing bars are arranged in advance on the top surface of the concrete that has already been constructed in the columnar structure, and a predetermined cradle is provided at the upper end of each of the preceding main reinforcing bars. Attaching process;
A step of installing a horizontal frame member of a predetermined shape on the plurality of cradles, and temporarily fixing each of the main reinforcing bars arranged in advance to the horizontal frame member;
A plurality of sets of brace materials are arranged between the top surface of the concrete that has been constructed and the horizontal frame material, and the positioning of the horizontal frame material is adjusted by adjusting the length of each set of brace materials. Process,
Placing the main reinforcing bars other than the previously arranged main reinforcing bars among the plurality of main reinforcing bars on the upper surface of the constructed concrete, using the horizontal frame material subjected to the positioning adjustment as a guide member. A method for constructing a columnar structure characterized by   A plurality of positioning recesses for positioning the plurality of main reinforcing bars are formed on the peripheral surface of the horizontal frame member at predetermined intervals in the circumferential direction of the horizontal frame member. Item 2. A method for constructing a columnar structure according to Item 1.   The method for constructing a columnar structure according to claim 1 or 2, wherein an assembly steel material obtained by assembling a plurality of steel materials is used as the horizontal frame material. As each steel material constituting the assembly steel material, using a composite steel material in which a steel plate is welded to a shape steel,
The method for constructing a columnar structure according to claim 3, wherein the plurality of positioning recesses in each composite steel material is formed on the steel plate.   5. The method of constructing a columnar structure according to claim 3, wherein a movable steel material having a predetermined number of positioning recesses is attached to a predetermined position of the assembled steel material.   The method for constructing a columnar structure according to any one of claims 1 to 5, wherein a member having a U-shaped concave portion for engaging with each main reinforcing bar is used as each cradle.   As each of the main reinforcing bars, a deformed reinforcing bar having a threaded portion formed on the outer peripheral surface is used, and a pair of lock nuts is attached in advance to each of the main reinforcing bars arranged in advance. The columnar structure construction method according to any one of claims 1 to 6, wherein the cradle is attached to the main reinforcing bars by sandwiching the cradle.   The method for constructing a columnar structure according to any one of claims 1 to 7, characterized in that a connected brace material constituted by adding a plurality of steel materials is used as each set of brace materials.

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