Formwork structure for reinforced concrete column

Abstract

To efficiently form a rectangular cylindrical concrete casting space by smoothly joining and integrating four separate formwork structures that are erected on each side of a reinforced concrete column with a rectangular cross section.SOLUTION: In each support beam joining structure 20, a corner joining piece 21 having a pair of abutment plates 21a, 21a is attached so as to fit from the outside into the right-angle portion between each of end side surfaces 17b, 17b of a pair of adjacent divided support beams 15, 15 arranged at right angles, with an end face 17a of one divided support beam 15 abutting against the end side surface 17b in an area spaced from the end face 17a of the other divided support beam 15. In this way, by joining the end side surfaces 17b, 17b together, it is possible to form an annular support beam 14 that is continuous in a rectangular ring shape.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a formwork structure for reinforced concrete columns, and in particular to a formwork structure for reinforced concrete columns that is installed when adding a reinforcing reinforced concrete layer around an existing reinforced concrete column with a rectangular cross-section, or when constructing a new reinforced concrete column with a rectangular cross-section. [Background technology]

[0002] In construction work to seismically reinforce existing reinforced concrete bridge piers that were constructed more than several decades ago, or other old existing reinforced concrete pillars, which have a rectangular cross section, common methods include the RC wrapping method, in which reinforcing bars are assembled around the existing reinforced concrete pillars such as bridge piers, formwork is installed, and additional reinforcing concrete is poured, and the steel plate wrapping method, in which reinforcing steel plates are wrapped around existing reinforced concrete pillars such as bridge piers, and a hardening material such as non-shrink mortar or epoxy resin is filled between the wrapped reinforcing steel plates and the concrete frame to integrate them.

[0003] In the RC lining method, when installing formwork around an existing reinforced concrete column, the outer concrete surface is treated with, for example, a water jet to create an uneven surface. Then, anchors are driven into the treated uneven surface, and separators are attached to the anchors. The separators then position the installed formwork while maintaining a predetermined gap between it and the concrete surface. This requires driving multiple anchors into the concrete surface to ensure the installed formwork has sufficient strength to withstand the internal pressure applied to the formwork when the reinforcing concrete is poured, which requires a lot of work. Furthermore, adjusting the lengths of the separators connected to the multiple anchors to maintain a predetermined gap between the concrete surface and the formwork also requires a lot of work.

[0004] On the other hand, for example, Patent Document 1 below discloses a formwork device for a rectangular columnar concrete structure that can support from the outside the load caused by internal pressure applied to the formwork during concrete pouring when constructing a new rectangular columnar concrete structure without using many separators. The formwork device described in Patent Document 1 includes a pair of formworks having inner peripheral surfaces corresponding to approximately half of the outer peripheral surface of the rectangular columnar concrete structure to be constructed, multiple wooden supports attached to the outer peripheral portions of the formwork so as to extend in the vertical direction, and multiple stages of retaining members attached continuously in a rectangular ring shape circumferentially around the outer peripheral portions of the multiple wooden supports. The retaining members are formed by beam members on four sides, whose ends are connected and fixed integrally at four intersecting corners via corner fixing guides or retrofitting guides. As a result, the load caused by internal pressure applied to the formwork during concrete pouring can be supported from the outside by the retaining members attached continuously in a rectangular ring shape circumferentially via the multiple wooden supports attached to the outer peripheral portions of the formwork so as to extend in the vertical direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-181439 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the formwork apparatus described in Patent Document 1, a pair of formworks are assembled in a lying position in a work area above ground away from the construction location of the rectangular columnar concrete structure, and then the formwork apparatus is constructed by assembling a pair of formworks and attaching multiple wooden supports and multiple stages of support members arranged in a rectangular ring shape. The formwork apparatus is then raised vertically using a crane or the like, and then lifted and installed at the construction location. Therefore, as the size of the rectangular columnar concrete structure to be constructed increases, the formwork apparatus becomes heavy and bulky, requiring a lot of effort to lift and transport the entire apparatus and to accurately install it at the desired construction location. In particular, when a reinforcing layer of reinforced concrete is poured around an existing reinforced concrete column with a rectangular cross-section, structures above the existing reinforced concrete column, such as a bridge abutment, can get in the way, making it difficult to lift and install the formwork apparatus in the desired location.

[0007] For these reasons, a method has been considered for more easily forming a rectangular cylindrical concrete pouring space or rectangular column-shaped concrete pouring space without using many separators, even when targeting large reinforced concrete columns with a rectangular cross-section. This involves forming four separate formwork structures that are arranged along each side of the rectangular cross-section, erecting each of the four separate formwork structures individually, and then connecting and integrating them at the concrete pouring point, thereby assembling and installing a rectangular cylindrical main formwork around the target reinforced concrete column.However, if a means is developed that allows the four erected separate formwork structures to be more smoothly connected and integrated, it is thought that it will be possible to more efficiently form a rectangular cylindrical concrete pouring space or rectangular column-shaped concrete pouring space using a main formwork assembled into a rectangular cylindrical shape.

[0008] The object of the present invention is to provide a formwork structure for reinforced concrete columns that allows four separate formwork structures that are individually erected along each face of a target reinforced concrete column having a rectangular cross-sectional shape to be smoothly connected and integrated, thereby making it possible to more simply and efficiently form a rectangular cylindrical concrete pouring space or a rectangular columnar concrete pouring space using a main formwork assembled into a rectangular cylindrical shape. [Means for solving the problem]

[0009] The present invention provides a formwork structure for a reinforced concrete column, which is installed when pouring an additional reinforced concrete layer around an existing reinforced concrete column having a rectangular cross-section, or when constructing a new reinforced concrete column having a rectangular cross-section, and which comprises a cylindrical main body formwork assembled into a rectangular cylindrical shape of a predetermined height by arranging a plurality of formwork units in a connected manner, and annular support beams attached in a continuous rectangular ring shape in a plurality of stages around the outer periphery of the cylindrical main body formwork, wherein the cylindrical main body formwork is formed into a rectangular cylindrical shape by joining together four divided main body formworks which are respectively arranged along the four sides of the rectangular cross-section, and the annular support beam is formed into a continuous rectangular ring shape on the outer periphery of the cylindrical main body formwork by joining together four divided support beams which are respectively arranged along the four sides of the rectangular cross-section, and each of the divided main body formworks and the divided support beams is assembled on the ground to form four divided formwork structures with the divided main body formworks abutting against the divided support beams, and these divided formwork structures are The split formwork structures are individually erected at the concrete pouring locations and connected together to form a rectangular cylindrical or rectangular columnar concrete pouring space using the cylindrical main formwork. When the four split formwork structures are connected together, the four split support beams are joined at right angles to each other using corner joint pieces with right-angled triangular portions at the four corner joints of each pair of adjacent split support beams, forming the annular support beam that is continuous in a rectangular ring shape. The joint structure of the support beam is such that, at each of the four corner joints where each pair of adjacent divided support beams are joined at right angles, the end face of one divided support beam is abutted against the end side face of the other divided support beam in an area spaced from the end face of the other divided support beam, and these end side faces are joined together via the corner joint piece, which has a pair of abutment plates arranged at right angles that can abut against these end side faces and are attached so as to be fitted from the outside into the right angle portion between each of the end side faces of the pair of adjacent divided support beams arranged at right angles,The above object has been achieved by providing a formwork structure for reinforced concrete columns, in which the annular support beams are formed in a continuous rectangular ring shape, and the load due to the internal pressure applied to the cylindrical main body formwork during concrete pouring is supported from the outside by the multiple stages of the annular support beams that abut the outer periphery of the cylindrical main body formwork and are continuous in a rectangular ring shape.

[0010] In the formwork structure for reinforced concrete columns of the present invention, it is preferable that the form units are made of steel formwork panels.

[0011] In addition, in the formwork structure for reinforced concrete columns of the present invention, it is preferable that the divided support beams are support beams for large formwork.

[0012] Furthermore, it is preferable that the formwork structure for reinforced concrete columns of the present invention is such that the formwork units are connected and assembled as a single unit via the divided support beams to form the divided main body formwork.

[0013] Furthermore, it is preferable that the formwork structure for reinforced concrete columns of the present invention is configured so that the corner joint pieces join each pair of adjacent divided support beams together at right angles at the four corner joints via fastening bolt members that pass through the divided support beams and are fastened and fixed.

[0014] In addition, it is preferable that the formwork structure for reinforced concrete columns of the present invention is such that the inner fastening plate that is attached in close contact with the end side of one of the divided support beams, opposite the side to which the corner joint piece is joined, is made of a plurality of block-shaped plate members arranged in a divided state.

[0015] Furthermore, in the formwork structure for reinforced concrete columns of the present invention, bolt fastening holes are formed in the abutment plates of the corner joint pieces, and it is preferable that the bolt fastening holes are elongated holes that are elongated in the lengthwise direction of the abutment plates. [Effects of the Invention]

[0016] According to the formwork structure for reinforced concrete columns of the present invention, four separate formwork structures erected along each face of a reinforced concrete column having a target rectangular cross-sectional shape can be smoothly connected and integrated, making it possible to more easily and efficiently form a rectangular cylindrical concrete pouring space or a rectangular columnar concrete pouring space using a main formwork assembled into a rectangular cylindrical shape. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 3 is a side view taken along the line BB in FIG. 2, illustrating a reinforcement method for a reinforced concrete column carried out using a formwork structure for a reinforced concrete column according to a preferred embodiment of the present invention. [Figure 2] 2 is a top view taken along the line AA in FIG. 1, illustrating a reinforcement method for a reinforced concrete column carried out using a formwork structure for a reinforced concrete column according to a preferred embodiment of the present invention. FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along CC in FIG. 1, illustrating a formwork structure for a reinforced concrete column according to a preferred embodiment of the present invention. [Figure 4] FIG. 4 is a side view of FIG. 3 viewed from the right side, illustrating the form structure for a reinforced concrete column according to a preferred embodiment of the present invention. [Figure 5] FIG. 10 is a perspective view illustrating a form unit made of steel form panels, viewed from the rear side. [Figure 6] FIG. 2 is a perspective view illustrating a split formwork structure. [Figure 7] FIG. 2 is a perspective view illustrating a divided support beam. [Figure 8]4(a) is an enlarged view of part D in FIG. 3 explaining the joint structure of the support beam, (b) is an enlarged view of part E in (a), and (c) is a cross-sectional view taken along FF in (a). [Figure 9] Explaining the corner joint piece, (a) is a top view, (b) is an outer side view of (a) seen from the right side, and (c) is an inner side view of (a) seen from below. [Figure 10] FIG. 2(a) is a front view illustrating an outer fastening plate, and FIG. 2(b) is a front view illustrating an inner fastening plate. [Figure 11] 1(a) to 1(c) are process diagrams illustrating a reinforcement method for a reinforced concrete column. [Figure 12] (a) and (b) are process diagrams explaining a reinforcement method for reinforced concrete columns. [Figure 13] (a) is an enlarged view of part G in Figure 12(a), illustrating the state in which the divided main body formwork is lifted and its lower end is supported by a height-adjustable support metal fitting, and (b) is an enlarged view of part H in (a). [Figure 14] (a) is a front view of the height-adjustable support bracket, and (b) is a side view. DETAILED DESCRIPTION OF THE INVENTION

[0018] As shown in Figures 1 and 2, a formwork structure 10 for a reinforced concrete column according to a preferred embodiment of the present invention is preferably installed as a formwork structure surrounding an existing reinforced concrete column, for example, a reinforced concrete pier 50 having a rectangular cross section, when a reinforcing reinforced concrete layer 51 (see Figure 11) is poured around the pier 50, to form a rectangular ring-shaped cylindrical concrete pouring space (rectangular cylindrical pouring space) 52 (see Figure 3) between the pier 50 and its outer surface. The form structure 10 for a reinforced concrete column of this embodiment is a simple construction method in which a plurality of split form structures 16, preferably assembled on the ground in a flat rectangular shape, are lifted and installed around a pier 50, and the split main form 13 is connected and integrated into a cylindrical shape. This allows for efficient and easy formation of a rectangular cylindrical concrete pouring space 52 around the existing pier 50, and also allows for stable and strong support from the outside of the formwork (cylindrical main form) 12 due to the internal pressure exerted on the formwork during concrete pouring, without the need for multiple separators 53 (see FIG. 3). Furthermore, the form structure 10 for a reinforced concrete column of this embodiment allows for smooth connection and integration of four split form structures 16 erected along each side of the existing pier 50, which is a reinforced concrete column having a rectangular cross-sectional shape, allowing for easier and more efficient formation of a rectangular cylindrical concrete pouring space 52 using the tubular main form 12 assembled into a rectangular cylindrical shape.

[0019] The formwork structure 10 for a reinforced concrete column of this embodiment is a formwork structure that is installed when pouring a reinforcing reinforced concrete layer 51 around an existing reinforced concrete column, such as a reinforced concrete pier 50 with a rectangular cross-section, and as shown in Figures 3 to 5, it is composed of a cylindrical main body formwork 12 assembled into a rectangular cylindrical shape with a rectangular hollow cross-section of a predetermined height by arranging a plurality of formwork units 11 (see Figure 5) in a connected manner, and annular support beams 14 attached in multiple stages in a rectangular ring shape circumferentially along the outer periphery of the cylindrical main body formwork 12. The cylindrical main body form 12 is formed into a rectangular cylindrical shape by joining together four separate main body formworks 13, each arranged along the four sides of the rectangular cross section of the pier 50, and the annular support beam 14 is formed into a continuous rectangular ring shape around the outer periphery of the cylindrical main body form 12 by joining together four separate support beams 15, each arranged along the four sides of the rectangular cross section of the pier 50. Each separate main body formwork 13 and separate support beam 15 are assembled on the ground to form a separate formwork structure 16 with the separate main body formwork 13 made of form units 11 abutting and joining to the separate support beams 15 (see Figure 6). These separate formwork structures 16 are individually erected at the concrete pouring location and connected together to form a rectangular cylindrical concrete pouring space 52 between the cylindrical main body formwork 12 and the existing pier 50. When concrete is poured, the load due to the internal pressure applied to the cylindrical main body form 12 can be stably and firmly supported from the outside by a plurality of stages of annular support beams 14 that abut the outer periphery of the cylindrical main body form 12 and are continuous in a rectangular ring shape.

[0020] In this embodiment, as described above, the reinforced concrete column form structure 10 is formed by assembling each of the divided main body formworks 13 and divided support beams 15 on the ground, forming four divided formwork structures 16 with the divided main body formworks 13 abutting and joined to the divided support beams 15, and these divided formwork structures 16 are individually erected at the concrete pouring locations and connected together to form a rectangular cylindrical concrete pouring space 52 between the cylindrical main body formwork 12 and the existing pier 50. When the four divided formwork structures 16 are connected together, the four divided support beams 15 are joined at right angles to each other at the four corner joints of each pair of adjacent divided support beams 15 using corner joint pieces 21 having right-angled triangular portions, thereby forming a rectangular ring-shaped continuous support beam 14 by a support beam joint structure 20, as shown in FIG. In this embodiment, the support beam joint structure 20 is such that, at each of the four corner joints where adjacent pairs of divided support beams 15 are joined at right angles, as shown in Figures 8(a) to (c), the end face 17a of one divided support beam 15 is abutted against the end side face 17b in an area spaced from the end face 17a of the other divided support beam 15, and these end side faces 17b, 17b are joined together via a corner joint piece 21 having a pair of abutment plates 21a, 21a arranged at right angles that can abut against these end side faces 17b, 17b, which are attached so as to be fitted from the outside into the right-angle portion between each of the end side faces 17b, 17b of the pair of adjacent divided support beams 15, 15 arranged at right angles, thereby forming a continuous rectangular annular support beam 14.

[0021] In addition, in this embodiment, the formwork units 11 made of steel formwork panels are connected and assembled as a single unit via the divided support beams 15, as described above, to form the divided main body formwork 13.

[0022] Furthermore, in this embodiment, the corner joint piece 21 is designed to join each pair of adjacent split support beams 15 together at right angles at the four corner joints using fastening bolt members 22 that pass through the split support beams 15 and are fastened and fixed.

[0023] In this embodiment, the form units 11 constituting the cylindrical main body form 12 and the divided main body form 13 are preferably steel form panels known as metal forms. As shown in Fig. 5, the steel form panel 11 is a known steel form member having a height of, for example, about 55 mm, and is composed of a vertically (horizontally) long rectangular face plate 11a, approximately 600 to 1,800 mm in length and 200 to 300 mm in width, and ribs 11b, such as vertical ribs, horizontal ribs, central vertical ribs, and central horizontal ribs, which are integrally joined in an upright state to the back side of the face plate 11a. The steel form panel 11 has a height of, for example, about 55 mm, and is formed with a plurality of fastening holes 11c, such as tie rod holes, U-clip holes, and nail holes, at appropriate locations on the ribs 11b, such as the vertical ribs, horizontal ribs, central vertical ribs, and central horizontal ribs. By engaging locking hardware 11d (see FIG. 6), such as U-clips or hook bolts, with these locking holes 11c, multiple steel form panels 11 are connected lengthwise and widthwise, preferably to form a rectangular flat plate of a predetermined size, thereby forming a divided main body form 13 having a predetermined height. Four divided main body form panels 13 are formed, and as will be described later, at a construction site where a reinforcing reinforced concrete layer 51 is poured around a reinforced concrete pier 50, these divided main body form panels 13 are connected and integrated to form a cylindrical main body form 12 (see FIG. 3), preferably having a rectangular hollow cross section and a predetermined height. For example, Metal Form manufactured by Okaya Construction Materials Co., Ltd. can be preferably used as the steel form panel that forms the form unit 11.

[0024] The annular support beam 14, which is attached in multiple stages in a rectangular ring shape around the outer periphery of the cylindrical main formwork 12 made of multiple steel formwork panels 11, is preferably composed of four segmented support beams 15. These segmented support beams 15 can be formed using various steel materials such as H-shaped steel and I-shaped steel. In this embodiment, the segmented support beams 15 can be formed using a support beam specifically designed for formwork, as shown in Figures 6 and 7. More specifically, they can be formed using a "wide panel beam" manufactured by Okaya Construction Materials Co., Ltd. The large-scale formwork support beam 15, which is a wide panel beam, is preferably formed by connecting a pair of channel steels 15a, each having a plurality of rectangular through-holes 15b formed at predetermined intervals along its length, back to back with gaps 15c through which bolts can be inserted, via end connecting plates 15d.

[0025] As will be described later, when the divided support beams 15 are installed in multiple stages (see Figure 4), through-holes 15b of the channel steel 15a of the large-form support beams that form the divided support beams 15 are inserted with through-holes 15e, such as square pipes, and the inserted through-holes 15e are fastened to the outer opening edges via square pipe washers 15f (see Figure 6), thereby connecting the large-form support beams 15 arranged in multiple stages spaced apart in the vertical direction. Furthermore, fastening hardware 11d, such as a hook bolt, fastened to fastening holes 11c in the ribs 11b of the steel form panels 11 that form the divided main-body formwork 13 is fastened to the opening edges on the inside (the side of the divided main-body formwork 13) of the through-holes 15b via beam washers 15g (see Figure 6). This makes it possible to form a split formwork structure 16 by abutting and joining the split main formwork 13, which is made up of multiple steel formwork panels 11 connected vertically and horizontally, to the split support beams 15 arranged in multiple stages through the ground assembly work described below (see Figure 4).The length of the split support beams 15 can be adjusted appropriately so that it corresponds to one side of the annular support beam 14, which is continuous in a rectangular ring shape, by connecting and joining unit beam materials of a predetermined length together in the longitudinal direction via end connecting plates 15d attached to the ends (see Figure 7).

[0026] In this embodiment, at a construction site where a reinforcing reinforced concrete layer is poured around a reinforced concrete pier 50, as shown in Figures 1 and 4, the structure is assembled on the ground in a work area away from the pier 50, for example, so that four split formwork structures 16 are formed by a split main formwork 13 made up of a predetermined number of formwork units 11 arranged vertically and horizontally, supported by multiple parallel split support beams 15, and then abutting and joining the split main formwork 13 to these split support beams 15 as a single unit.

[0027] In other words, in the split formwork structure 16, form units 11 made of a predetermined number of steel formwork panels, each capable of forming, for example, a rectangular split main body formwork 13 of a predetermined size, are arranged in a row and column, for example with their back sides facing up, and these steel formwork panels 11 are connected to each other using locking hardware 11d to form an integrated split main body formwork 13.At the same time, multiple stages of split support beams 15 are extended parallel to each other on the back side of the formed split main body formwork 13, with one flange surface of each beam abutting the tip of the rib 11b of the steel formwork panel 11 (see Figures 4 and 6), and the split main body formwork 13 made of steel formwork panels 11 is connected to these multiple stages of split support beams 15 so that they abut against each other using beam washers 15g and locking hardware 11d such as hook bolts (see Figure 6). This makes it possible to form, by assembling on the ground, four split form structures 16, each of which has a split main body form 13 made up of a plurality of steel form panels 11 arranged lengthwise and crosswise joined integrally to a plurality of split support beams 15 (see Figure 4). Furthermore, with the split support beams 15 installed in multiple stages, the through members 15e are inserted and engaged into the through openings 15b of the channel steel 15a constituting the large form support beam, thereby connecting these multiple stages of split support beams 15 to one another, so that the split form structures 16 can stably maintain their strong shape-retaining rigidity when they are lifted up and erected at the location where concrete is to be poured.

[0028] The four split form structures 16 assembled on the ground are stored in a stacked state, for example, in a section at the construction site away from the pier 50, as shown in Figures 1 and 2. The stored split form structures 16 can be easily lifted up by using a heavy lifting machine 60 such as a crane selected according to the weight of the structure and the size of the work area, and individually erected at the concrete pouring location of the lowest construction rod, where reinforcing bars 54 have been previously placed, for pouring additional concrete to form a reinforcing concrete layer 51, preferably around the lower end portion of the pier 50, which is a reinforced concrete column to be reinforced. As will be described later, the four erected split formwork structures 16 are integrated by joining the four split support beams 15 of each stage at right angles to each other via corner joint pieces 21, preferably having right-angled triangular portions, using a support beam joint structure 20 (see Figure 3). This joins the four split support beams 15 at each stage together at right angles to each other via corner joint pieces 21, preferably having right-angled triangular portions, to form annular support beams 14 at each stage, which are preferably continuous in a rectangular ring shape in the circumferential direction.The four split main body formworks 13 are assembled into a cylindrical shape with a rectangular hollow cross section using the above-mentioned tie rod holes, U-clip holes, etc. (see Figure 5), and locking hardware 11d, such as U-clips and hook bolts, to form the tubular main body formwork 12 (see Figure 3).This makes it possible to obtain the formwork structure 10 for reinforced concrete columns of this embodiment, in which the annular support beams 14 and the tubular main body formwork 12 are integrated.

[0029] In addition, in this embodiment, a rectangular cylindrical concrete pouring space 52 of a predetermined width corresponding to the thickness of the reinforced concrete layer 51 to be poured is formed between the inner formwork surface of the steel formwork panel 11 constituting the cylindrical main body formwork 12 of the reinforced concrete column formwork structure 10 thus provided around the periphery, preferably of the lower end portion, of the existing pier 50 and the outer surface of the existing pier 50, as the concrete pouring location for the lowest construction rod. Such rectangular cylindrical concrete pouring spaces 52 of a predetermined width can be formed, for example, by supporting spacer separators 53 (see Figure 3) on the concrete surface around the periphery of an existing pier 50, using anchors or the like that have been driven into the pier 50 in advance, and attaching them in a balanced arrangement at multiple appropriate locations.By positioning each split formwork structure 16 via these spacer separators 53 and installing it on the outer periphery surrounding the existing pier 50, it becomes possible to precisely maintain rectangular cylindrical concrete pouring spaces 52 of a predetermined width corresponding to the thickness of the reinforcing reinforced concrete layer 51 on the outer periphery of the existing pier 50.

[0030] Furthermore, in this embodiment, temporary work scaffolding 55 for various tasks is assembled and installed along each of the four sides of the rectangular cross-sectional pier 50 at the outer periphery, with a predetermined distance between the pier and the outer periphery to allow for the installation of reinforcing bars 54 and split formwork structures 16. The temporary work scaffolding 55 can be preferably formed using, for example, lightweight Darwin scaffolding, which can lift multiple spans as a single unit. The Darwin scaffolding preferably has short ties so that the spans can be divided. Each split formwork structure 16 can be installed on the outside of each of the four sides of the pier 50, as needed, by removing and restoring the work scaffolding on one or two of the work scaffolding 55 installed on the outer periphery of each of the four sides.

[0031] As shown in Figure 3, the four installed split formwork structures 16 have four split support beams 15 attached to them at each stage. The split support beams 15 are connected together at right angles to each other at the four corner joints of adjacent pairs of split support beams 15 using corner joint pieces 21 with right-angled triangular portions. This connects these split support beams 15 together using a support beam joint structure 20, making it possible to efficiently form the reinforced concrete column formwork structure 10 of this embodiment, which includes a cylindrical main formwork 12 assembled into a cylindrical shape with a rectangular hollow cross section of a predetermined height, and annular support beams 14 attached in multiple stages and extending in a rectangular ring shape around the outer periphery of the cylindrical main formwork 12.

[0032] 9(a) to 9(c), the corner joint piece 21 constituting the support beam joint structure 20 is a steel joint member having a planar shape of a right-angled equilateral triangle, and is formed by a pair of vertically (horizontally) elongated abutment plate portions 21a, for example, approximately 345 mm long and 129 mm wide, arranged at right angles to each other and joined by welding or the like, and a pair of reinforcing rib plates 21b, each having a right-angled equilateral triangular shape, arranged so as to straddle the upper or lower edge portions of the pair of abutment plates 21a and fitted into the inner right-angle portions of the abutment plates 21a and fixed by welding or the like. Each abutment plate 21a has a plurality of bolt fastening holes 21c formed in its widthwise center at predetermined intervals along its length. These bolt fastening holes 21c are adapted to fasten one end of a fastening bolt member 22 for tightly joining the abutment plate 21a of the corner joint piece 21 to the end side surfaces 17b, 17b of each of a pair of adjacent divided support beams 15, 15. Furthermore, the bolt fastening holes 21c formed in each abutment plate 21a are preferably elongated holes extending in the longitudinal direction of the abutment plate 21a. This allows for effective absorption of misalignment of the fastening bolt member 22 to the abutment plate 21a when, for example, a length-adjusting plate member needs to be interposed between the end surface 17a of one divided support beam 15 and the end side surface 17b of the other divided support beam 15 at each corner joint between each pair of adjacent divided support beams 15 in order to fine-tune the lateral (horizontal) length of the divided support beam 15 and the divided formwork structure 16 to the size of the existing pier 50.

[0033] To join each pair of adjacent split support beams 15 at right angles using corner joint pieces 21 at the four corner joints of the annular support beam 14, as shown in Figures 3 and 8(a) to (c), with four split formwork structures 16 each erected around the lower end portion of the pier 50, the split support beams 15, 15 of each stage attached to the outside of the split formwork structures 16 are positioned so that the end face 17a of one split support beam 15 abuts against the end side face 17b in an area spaced from the end face 17a of the other split support beam 15 at each corner joint between each pair of adjacent split support beams 15, and these pairs of split support beams 15 are arranged at right angles (see Figure 8(a)). Thereafter, at each corner joint, the corner joint piece 21 is fitted from the outside into the perpendicular portion formed by the end side surfaces 17b of the pair of perpendicularly arranged split support beams 15, 15, so that its pair of abutment plates 21a, 12a are respectively superimposed on the end side surfaces 17b, 17b of the perpendicularly arranged split support beams 15, 15. Then, with the pair of abutment plates 21a, 12a of the corner joint piece 21 respectively overlapped on the end side surfaces 17b, 17b of the split support beams 15, 15, the fastening bolt member 22 is inserted through the bolt fastening holes 21c of the abutment plates 21a, 12a into the gap 15c (see Figure 6) held between the pair of channel steels 15a of the split support beams 15, 15, so that the other end of the fastening bolt member 22 can be positioned so that it protrudes from the end side surface 17b' opposite to the end side surface 17b to which the corner joint piece 21 is joined (see Figure 8(c)).

[0034] As a result, the fastening bolt member 22 inserted through the bolt fastening hole 21c and the gap 15c between the pair of channel steels 15a, 15a of the divided support beams 15, 15 can have one end fastened using a washer or nut to the abutment plate 21a, 21a of the corner connection piece 21 that comes into close contact with the end side surface 17b, 17b of the divided support beam 15, 15 at the right angle on the side where the corner connection piece 21 is located, and the other end can be fastened using a washer or nut to the fastening plate 22a, 22b that comes into close contact with the end side surface 17b', 17b' on the opposite side from the corner connection piece 21. This also makes it possible to firmly fix the corner connection piece 21 to the right angle portion formed by the end side surfaces 17b of the pair of divided support beams 15, 15 that are arranged at a right angle, with the corner connection piece 21 fitted from the outside.

[0035] In this embodiment, each pair of adjacent split support beams 15 is fastened and fixed at four corner joints, each joined at a right angle via the corner joint pieces 21, as described above, preferably using three fastening bolt members 22. In this embodiment, fastening plates 22a, 22b are attached to the end side surface 17b' opposite to the end side surface 17b to which the abutment plates 21a, 12a of the corner joint piece 21 are in close contact, interposed between washers and nuts, and are in close contact with the end side surface 17b'. The outer fastening plate 22a is disposed on the outer end side surface 17b' opposite to the side to which the corner joint piece 21 is joined, on the other split support beam 15 to which the end surface 17a is in contact. This outer fastening plate 22a is a single, continuous, horizontally elongated plate member capable of simultaneously fastening three fastening bolt members 22, as shown in FIG. 10(a). In addition, the inner fastening plate 22b, which is attached in close contact with the inner end side surface 17b' on the opposite side to the side where the corner connecting piece 21 of one of the divided support beams 15, which abuts the end face 17a, is made of multiple (two in this embodiment) block-shaped plate members that are arranged in a divided state as shown in Figure 10(b) and can fasten three connecting bolt members 22 in, for example, two locations.

[0036] The inner fastening plates 22b attached in close contact with the inner end side surface 17b' of one of the divided support beams 15 against which the end face 17a abuts are formed as a plurality of segmented plate members, which make it possible to arrange each of the segmented inner fastening plates 22b while avoiding interference with the rear-side ribs 11b protruding from the rear of the steel form panel 11 that constitutes the divided main body form 13, which is connected with the ribs 11b abutting the inner end side surface 17b' of one of the divided support beams 15. This makes it possible to fasten the other ends of the three fastening bolt members 22 to the inner fastening plates 22b in a state where the inner fastening plates 22b are in close contact with the inner end side surface 17b' and the rear-side ribs 11b of the steel form panel 11 are abutting against the inner end side surface 17b' in a portion that does not interfere with the rear-side ribs 11b.

[0037] In this embodiment, the above-mentioned support beam joining structure 20 using corner joining pieces 21 connects the four split support beams 15 of each stage of the four split formwork structures 16 together to form continuous rectangular ring-shaped support beams 14, and the split main formwork 13 made up of multiple steel formwork panels 11 arranged vertically and horizontally and supported by the split support beams 15 is integrated by connecting the steel formwork panels 11 at their side ends using locking hardware 11d such as U-clips and hook bolts, making it possible to form a cylindrical main formwork 12 with a rectangular hollow cross-section. As a result, the formwork structure 10 for reinforced concrete columns of this embodiment, which includes the cylindrical main body formwork 12 assembled into a cylindrical shape of a predetermined height and the annular support beams 14 attached in multiple stages and extending in a ring shape in the circumferential direction along the outer periphery of the cylindrical main body formwork 12, is installed at a predetermined height around the lower end portion of the existing pier 50, and a rectangular cylindrical concrete pouring space 52 is formed with a predetermined distance maintained between it and the lower end portion of the existing pier 50. Furthermore, concrete is poured into the formed cylindrical concrete pouring space 52 at the lower end portion of the pier 50, and a reinforcing concrete layer 51 for reinforcing the lowest construction rod is constructed.

[0038] In this embodiment, the existing pier 50 is, for example, a reinforced concrete column of considerable height, and when the above-mentioned reinforced concrete column formwork structure 10 is used to construct a reinforcing reinforced concrete layer 51 around the pier 50, the following reinforcement method for reinforced concrete columns is implemented, which makes it possible to use the divided main body formwork 13 that makes up the tubular main body formwork 12 in multiple rotations from the bottom to the top of the pier 50, making it possible to efficiently construct a reinforcing reinforced concrete layer 51 around the pier 50 by adding more concrete to the pier 50.

[0039] That is, in this embodiment, the reinforcement method for reinforced concrete columns is a reinforcement method using the above-mentioned tubular main body formwork 12, which is formed into a cylindrical shape of a predetermined height by joining together multiple divided main body formworks 13 in the circumferential direction to construct a reinforcing reinforced concrete layer 51 around an existing reinforced concrete column, or pier 50, as shown in Figures 11(a) to (c) and 12(a) and (b).The divided main body formwork 13 that constitutes the tubular main body formwork 12 is, as described above, formed by multiple formwork unit bodies, or steel formwork panels 11, which are connected together as a single unit via divided support beams 15 and assembled to a predetermined height, and is preferably adapted to be rotated multiple times from the bottom to the top of the existing reinforced concrete column, or pier 50. A cylindrical main body form 12 is installed around the lower end portion of the existing pier 50 (see FIG. 11(a)), and concrete is poured into a rectangular cylindrical concrete pouring space 52 held between the existing pier 50 and the cylindrical main body form 12 to form a reinforcing concrete layer 51 for the lowest construction rod (see FIGS. 11(a) and 11(b)). Then, a form sliding process (see FIG. 11(a) and 11(b)) is carried out in which each of the divided main body form 13 of the removed cylindrical main body form 12 is slid away from the formed reinforcing concrete layer 51 for the lowest construction rod while remaining upright. 11(c)) and the resulting work space 56 between the bottom reinforced concrete layer 51 and the divided main body formwork 13. A formwork surface cleaning process (see Figure 11(c)) is carried out in which the inner formwork surface of each divided main body formwork 13 is cleaned, and then a lifting and repurposing process (see Figure 12(a)) is carried out in which the divided main body formwork 13 whose inner formwork surface has been cleaned is lifted upward and re-installed as a component of the cylindrical main body formwork 12 to form the reinforcing concrete layer 51 of the next layer of construction rods.

[0040] In this embodiment, the reinforcement method for a reinforced concrete column preferably uses the divided main body formwork 13 converted into the next-stage construction rod in the lifting and conversion process to pour concrete into the rectangular cylindrical concrete pouring space 52 held between the tubular main body formwork 12 installed around the existing pier 50 and the existing pier 50, thereby forming a reinforcing concrete layer 51 for the next-stage construction rod, and then hangs down each divided main body formwork 13 of the removed tubular main body formwork 12 in an upright state to the part of the lowest-stage construction rod, and then lifts up the reinforcing concrete layer 51 for the lowest-stage construction rod formed. The following steps are carried out: a formwork hanging and moving process (see Figure 12(b)), in which the formwork is moved away from the concrete layer 51; a formwork surface re-scraping process (see Figure 12(b)), in which workers enter the work space 56 created between the bottom reinforced concrete layer 51 and scrape the inner formwork surface of each divided main body formwork 13; and a re-hoisting and reuse process, in which the divided main body formwork 13 with its inner formwork surface scraped is lifted upward and reinstalled as a component of the tubular main body formwork 12 to form the reinforced concrete layer 51 of the next level of construction rods.

[0041] Furthermore, in this embodiment, as described above, the reinforcement method for reinforced concrete columns involves installing temporary scaffolding 55 around the existing pier 50, which is used when assembling the reinforcing bars 54 and the tubular main body formwork 12, while maintaining space for the tubular main body formwork 12 to be arranged, and preferably, prior to the formwork sliding process or the formwork hanging and moving process, a scaffolding partial removal process (see Figures 11(c) and 12(b)) is carried out in which part of the temporary scaffolding 55 in the part of the lowest construction rod is removed so that the movement of the divided main body formwork 13 is not hindered.

[0042] In addition, in this embodiment, the reinforcement method for a reinforced concrete column preferably includes installing a cylindrical main body form 12 around the lower end portion of the existing pier 50, pouring concrete into a rectangular cylindrical concrete pouring space 52 held between the existing pier 50 and the cylindrical main body form 12, forming a reinforcing concrete layer 51 for the lowest construction rod, and after removing the divided main body form 13, leaving the divided main body form 13 at a predetermined height position on the surface of the upper end portion of the reinforcing concrete layer 51 for the lowest construction rod in the portion where the divided main body form 13 was removed, as shown in Figure 11 (c) and Figures 13 (a) and (b). The process involves a height-adjustment support hardware installation process in which height-adjustment support hardware 58 (see Figures 14(a) and (b)) is installed to engage and support the lower end of the divided main body formwork 16 using at least two embedded anchors 57 (see Figure 13(b)) as support members, and a form conversion assembly process (see Figure 12(a)) in which the demolded divided main body formwork 16 is lifted and, with its lower end engaged with the height-adjustment support hardware 58 (see Figure 13(b)), a tubular main body formwork 12 for forming the reinforcing concrete layer 51 of the next layer of construction rods is assembled.

[0043] 14(a) and 14(b), the height-adjustable support hardware 58 is a fastening hardware made of, for example, an angle iron with an L-shaped cross section, and has a joint surface 58a, which is one surface that is placed in close contact with the surface of the reinforced concrete layer 51, formed with a fastening slot 58c to which an adjustment plug 59a of a Form-Tie (registered trademark) 59 is fastened. The fastening slot 58c is formed to extend linearly at an angle with respect to a support surface 58b to which the lower end of the divided main body form 13 made of the steel form panel 11 is fastened. This makes it possible to appropriately adjust the height of the support surface 58b by changing the position of the fastening slot 58c to fasten the adjustment plug 59a that is screwed into the embedded anchor 57 (see FIG. 13(b)).

[0044] Furthermore, in this embodiment, the reinforcement method for a reinforced concrete column preferably uses the divided main body formwork 13 converted into the next-stage construction rod in the formwork conversion assembly process, and pours concrete into the rectangular cylindrical concrete pouring space 52 of concrete held between the cylindrical main body formwork 12 installed around the existing pier 50 and the existing pier 50, thereby forming a reinforcing concrete layer 51 for the next-stage construction rod, and after the divided main body formwork 16 is removed, the upper end portion of the reinforcing concrete layer 51 for the next-stage construction rod in the part where the divided main body formwork 13 was removed is poured. It is possible to carry out a height adjustment support hardware reinstallation process in which at least two embedded anchors 57 (see Figure 13(b)) left at a specified height position are used as support members to install height adjustment support hardware 58 (see Figures 14(a) and (b)) that engage and support the lower end of the divided main body formwork 13, and a formwork reuse assembly process in which the removed divided main body formwork 16 is lifted and its lower end is engaged with the adjustable support hardware 58, and then a tubular main body formwork 12 for forming the reinforcing concrete layer 51 of the next layer of construction rods is assembled.

[0045] Furthermore, in this embodiment, the reinforcement method for reinforced concrete columns involves installing temporary scaffolding 55 around the existing pier 50, as described above, to be used when assembling the reinforcing bars 54 and the tubular main body formwork 12, while maintaining space for the tubular main body formwork 12 to be arranged, and preferably using a lifting weight equipment 61 supported on the upper end part of the installed temporary scaffolding 55, it is possible to lift up and down the divided main body formwork 13 that is demolded and reused in the formwork conversion assembly process or formwork re-conversion assembly process.

[0046] Furthermore, according to the formwork structure 10 for reinforced concrete columns of this embodiment having the above-mentioned configuration, even in the case of a large-scale columnar concrete structure (pier) 50, it is possible to assemble it into a rectangular cylindrical shape more simply and accurately without using many separators 53, making it possible to efficiently and easily form a rectangular cylindrical concrete pouring space 52, and it is also possible to firmly support the load due to the internal pressure imposed on the formwork (cylindrical main body formwork) 12 when pouring concrete from the outside in a stable manner.

[0047] That is, according to this embodiment, each of the divided main body formworks 13 and divided support beams 15 is assembled on the ground to form a divided formwork structure 16 in a state where the divided main body formwork 13 made of formwork units (steel formwork panels) 11 is abutted and joined to the divided support beams 15, and these divided formwork structures 16 are individually erected at the concrete pouring locations and connected and integrated, so that a rectangular cylindrical concrete pouring space 52 is formed by the cylindrical main body formwork 12 between the existing pier 50, and there is no need to lift the cylindrical main body formwork 12 as a whole. Therefore, even if the pier 50 is large, it is possible to easily lift up the individual split formwork structures 16 without using a large crane or the like, and to efficiently install the cylindrical main body formwork 12 of a specified height around the existing pier 50.In addition, when pouring concrete, the load due to the internal pressure applied to the cylindrical main body formwork 12 can be firmly and stably supported from the outside by the multiple stages of annular support beams 14 that abut the outer periphery of the cylindrical main body formwork 12 and are continuous in a ring shape, without using many separators.

[0048] Furthermore, according to the formwork structure 10 for reinforced concrete columns of this embodiment having the above-mentioned configuration, the four split formwork structures 16 erected along each face of the pier 50, which is a reinforced concrete column having a target rectangular cross-sectional shape, can be smoothly connected and integrated, making it possible to more easily and efficiently form a rectangular cylindrical concrete pouring space 52 using the cylindrical main formwork 12 assembled into a rectangular cylindrical shape.

[0049] That is, according to this embodiment, when the four split formwork structures 16 are connected as a unit, the four split support beams 15 form a continuous annular support beam 14 in a rectangular ring shape by the support beam joint structure 20, and the support beam joint structure 20 is configured such that at each of the four corner joints where each pair of adjacent split support beams 15 are joined at right angles, the end face 17a of one split support beam 15 is abutted against the end side face 17b of the other split support beam 15, and these end side faces 17b, 17b are joined as a unit via corner joint pieces 21 attached by fitting from the outside into the right-angle portion between each of the end side faces 17b, 17b. Therefore, by simply fastening and fixing the corner joint pieces 21 to the right angle between the end side surfaces 17b, 17b, preferably using the fastening bolt members 22, it is possible to more smoothly connect and integrate the four split formwork structures that have been erected, making it possible to more efficiently form a rectangular cylindrical concrete pouring space 52 using the cylindrical main body formwork 12 assembled into a rectangular cylindrical shape, and during concrete pouring, the load due to the internal pressure applied to the cylindrical main body formwork 12 can be supported stably and firmly from the outside by the multiple stages of annular support beams 14 that abut the outer periphery of the cylindrical main body formwork 12 and are continuous in a ring shape, without using many separators.

[0050] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, the formwork structure for a reinforced concrete column of the present invention can be used not only when a reinforcing reinforced concrete layer is poured around an existing reinforced concrete column, i.e., a pier, having a rectangular cross-section, but also when constructing a new reinforced concrete column, such as a pier, having a rectangular cross-section, to form a rectangular column-shaped concrete pouring space. The reinforced concrete column does not necessarily have to be a pier, and the formwork structure for a reinforced concrete column of the present invention can also be used when reinforcing or constructing other reinforced concrete columns that constitute various structures. [Explanation of symbols]

[0051] 10. Formwork structure for reinforced concrete columns 11 Steel formwork panel (formwork unit) 11a Face plate 11b Rib 11c Locking hole 11d Locking hardware 12 Cylindrical main body formwork 13 Split main body formwork 14 Annular support beam 15 Split support beam 15a channel steel 15b Through opening 15c gap 15d End connecting plate 15e through material 15f Square Pipe Washer 15g beam washer 16 Split formwork structure 17a End face of split support beam 17b Side of end of split support beam 17b' The end side opposite to the end side to which the corner joint piece is joined 20 Support beam joint structure 21 Corner joint piece 21a Contact plate 21b Reinforced rib plate 21c Bolt fastening hole 22 Fastening bolt member 22a Outer fastening plate 22b Inner fastening plate 50 Bridge pier (reinforced concrete column) 51 Reinforced concrete layer 52 Rectangular cylindrical concrete casting space 53 Separator 54 Reinforced concrete 55 Work scaffolding 56 workspace 57 Buried anchor 58 Height adjustment support hardware 58a Joint surface part 58b Support surface part 58c Fastening slot 59 Form Tie (registered trademark) 59a Adjustment plug 60 Lifting Machine 61 Yang Chong Equipment

Claims

1. A formwork structure for a reinforced concrete column that is installed when constructing a reinforcing reinforced concrete layer around an existing reinforced concrete column having a rectangular cross-sectional shape, or when constructing a new reinforced concrete column having a rectangular cross-sectional shape. The system is configured to include a cylindrical main body formwork assembled into a rectangular cylindrical shape of a predetermined height by arranging a plurality of formwork units in a connected manner, and annular support beams attached in multiple stages in a rectangular ring shape in the circumferential direction along the outer periphery of the cylindrical main body formwork, The cylindrical main body form is formed into a rectangular cylindrical shape by joining together four divided main body form frames that are respectively arranged along the four sides of the rectangular cross section, and the annular support beam is formed into a continuous rectangular annular shape on the outer periphery of the cylindrical main body form by joining together four divided support beams that are respectively arranged along the four sides of the rectangular cross section, Each of the divided main body formworks and the divided support beams are assembled on the ground to form four divided formwork structures with the divided main body formworks abutting and joined to the divided support beams, and these divided formwork structures are individually erected at the concrete pouring locations and connected together to form a rectangular cylindrical or rectangular columnar concrete pouring space using the cylindrical main body formwork. When the four split formwork structures are connected together, the four split support beams are joined at right angles to each other at the four corner joints of each adjacent pair of split support beams using corner joint pieces having right-angled triangular portions, thereby forming the annular support beam that is continuous in a rectangular ring shape, The joint structure of the support beam is such that, at each of the four corner joints where each pair of adjacent divided support beams are joined at right angles, the end face of one divided support beam is abutted against the end side face of the other divided support beam in an area spaced from the end face of the other divided support beam, and these end side faces are joined together via the corner joint piece, which has a pair of abutment plates arranged at right angles that can abut against these end side faces and are attached so as to fit from the outside into the right angle portion between each of the end side faces of the pair of adjacent divided support beams arranged at right angles, thereby forming the annular support beam that is continuous in a rectangular ring shape. This formwork structure for reinforced concrete columns is designed so that the load caused by the internal pressure applied to the cylindrical main body formwork when pouring concrete is supported from the outside by multiple stages of the annular support beams that abut the outer periphery of the cylindrical main body formwork and are continuous in a rectangular ring shape.

2. 2. A form structure for reinforced concrete columns according to claim 1, wherein said form units are steel form panels.

3. 3. A form structure for reinforced concrete columns according to claim 1, wherein said divided support beams are support beams for large formwork.

4. 3. A form structure for a reinforced concrete column according to claim 1 or 2, wherein the form units are connected and assembled as a unit via the divided support beams to form the divided main body form.

5. 3. A formwork structure for reinforced concrete columns as described in claim 1 or 2, wherein the corner joint pieces are configured to join each pair of adjacent divided support beams together at right angles at the four corner joints via fastening bolt members that pass through the divided support beams and are fastened and fixed thereto.

6. 3. The formwork structure for reinforced concrete columns according to claim 2, wherein the inner fastening plate attached in close contact with the inner end side of the one divided support beam, opposite the side to which the corner joint piece is joined, is made up of a plurality of block-shaped plate members arranged in a divided state.

7. 3. A formwork structure for reinforced concrete columns according to claim 1, wherein a bolt fastening hole is formed in the abutment plate of the corner joint piece, and the bolt fastening hole is an elongated hole that is elongated in the length direction of the abutment plate.

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