Method for installing temporary work support

Abstract

To prevent the occurrence of punching shear breakage by optimizing the arrangement of a lower base plate or an upper base plate.SOLUTION: A method for installing a temporary work support using a temporary work support 1 which has a lower column 10 with a lower base plate 13 provided at a lower end of a lower pipe section 11 and an upper column 50 with an upper base plate 52 provided at an upper end of an upper pipe section 51, and in which a distance between the lower base plate 13 and the upper base plate 52 is adjustable, is provided. A positioning step is performed to position the upper base plate 52 so that a plurality of adjacent reinforcing bars are placed within the range of a punching shear on the basis of a reinforcement arrangement diagram when an outer edge of the upper base plate 52 is positioned diagonally with respect to the reinforcing bars. The temporary work support 1 is installed on the basis of the position determined in the positioning step, and an outer edge of the upper base plate 52 is arranged diagonally with respect to the plurality of adjacent reinforcing bars, so that the plurality of adjacent parallel reinforcing bars are placed within the range of the punching shear exerted by corners of the upper base plate 52.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for installing supports for temporary construction work to support reinforced concrete slabs during the demolition of a building, etc. [Background technology]

[0002] Demolition work on buildings and other structures often involves using heavy machinery to demolish the structures, starting from the upper floors and working downward. In this case, the strength of the building's floors (slabs) alone is insufficient to support the load of the heavy machinery. Therefore, temporary construction supports are erected between the upper and lower slabs on the lower floors where the heavy machinery is used. Furthermore, when installing these temporary construction supports, to prevent punching shear damage that would otherwise be caused by punching through the slab, the reinforcement diagram is typically checked and the rebar inside the concrete is positioned so that it lies within the punching shear range (the area extending at a 45-degree angle from the point where the upper base plate abuts the slab) of the base plates (seat plates) attached to the top and bottom of the temporary construction supports. Regarding this issue, for example, Patent Document 1 discloses a temporary construction support designed to reduce weight and improve durability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-62660 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the conventional method of installing temporary construction supports, if the installation location of the temporary construction supports shifts for some reason due to the balance between the size of the base plate and the spacing between the rebars, there is a risk that the rebars will fall out of the range of the punching shear of the temporary construction supports, and the load will be supported only by the concrete. This can be dangerous as it can cause the slab to be destroyed by the punching shear.

[0005] This is because, while the center-to-center distance between adjacent main rebars should ideally be 200 mm or less, older buildings constructed in the 1950s and 1960s, for example, extended the center-to-center distance between adjacent main rebars to, for example, 220 mm, in order to reduce the amount of rebar used, as long as it was not problematic for structural calculations. Furthermore, in the horizontal center of the slab, the top rebars were sometimes omitted by using bent rebars or by cutting the top rebars. Furthermore, this was due to adverse conditions, such as the fact that the cover depth for rebars at the time was limited to 20 mm, depending on the location (see Figure 10). Furthermore, under such adverse conditions, the slab could not support a high load due to the risk of punching shear failure, and the number of temporary construction supports had to be increased to some extent.

[0006] The present invention has been made in consideration of the above points, and aims to provide a method for installing supports for temporary construction work that optimizes the positioning of the lower base plate or upper base plate relative to the reinforcing bars, thereby bringing adjacent reinforcing bars within the range of the punching shear, thereby preventing the occurrence of punching shear failure. [Means for solving the problem]

[0007] The method for installing a support for temporary construction of the present invention includes the steps of: a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper tube portion and an upper base plate provided at the upper end of the upper tube portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be accommodated within the punching shear range of the slab, A method for installing a temporary work support, wherein at least the upper base plate of the lower base plate and the upper base plate is rectangular and has a side length of 140 mm or more and less than 170 mm, a positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the outer edge of the upper base plate is arranged diagonally relative to the reinforcing bars based on a reinforcing bar arrangement drawing; The temporary construction support is installed based on the position determined in the positioning process, and the outer edge of the upper base plate is positioned at an angle to the multiple parallel adjacent reinforcing bars, so that the multiple parallel adjacent reinforcing bars are within the range of the punching shear exerted by the corners of the upper base plate on the slab.

[0008] The method for installing a support for temporary construction of the present invention includes the steps of: a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper pipe portion and an upper base plate provided at the upper end of the upper pipe portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be placed within the punching shear range of the slab, A method for installing a temporary work support, wherein at least the upper base plate of the lower base plate and the upper base plate is rectangular and has a diagonal length of 184 mm or more and less than 226 mm, a positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the outer edge of the upper base plate is arranged diagonally relative to the reinforcing bars based on a reinforcing bar arrangement drawing; The temporary construction support is installed based on the position determined in the positioning process, and the outer edge of the upper base plate is positioned at an angle to the multiple parallel adjacent reinforcing bars, so that the multiple parallel adjacent reinforcing bars are within the range of the punching shear exerted by the corners of the upper base plate on the slab.

[0009] The method for installing a support for temporary construction of the present invention includes the steps of: a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper tube portion and an upper base plate provided at the upper end of the upper tube portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be accommodated within the punching shear range of the slab, A method for installing a temporary construction support, wherein the length of an imaginary line passing through the wide surface of at least the upper base plate of the lower base plate and the upper base plate is 184 mm or more and less than 226 mm from one end to the other end, A positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the virtual line is arranged in a direction perpendicular to the reinforcing bars based on a reinforcing bar arrangement drawing; The temporary construction support is installed based on the position determined in the positioning process, and the virtual line is arranged in a direction perpendicular to the multiple parallel adjacent reinforcing bars, so that the multiple parallel adjacent reinforcing bars are within the range of the punching shear exerted by one end and the other end of the upper base plate.

[0010] The method for installing a support for temporary construction of the present invention includes the steps of: a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper tube portion and an upper base plate provided at the upper end of the upper tube portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be accommodated within the punching shear range of the slab, A method for installing a temporary construction support, wherein the length of an imaginary line passing through the wide surface of at least the upper base plate of the lower base plate and the upper base plate is 226 mm or more and 283 mm or less from one end to the other end, A positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the virtual line is arranged in a direction perpendicular to the reinforcing bars based on a reinforcing bar arrangement drawing; The temporary construction support is installed based on the position determined in the positioning process, and the virtual line is arranged in a direction perpendicular to the multiple parallel adjacent reinforcing bars, so that the multiple parallel adjacent reinforcing bars are within the range of the punching shear exerted by one end and the other end of the upper base plate.

[0011] According to these methods for installing temporary construction supports of the present invention, the upper base plate of the temporary construction support can support multiple rebars that are parallel and adjacent (hereinafter sometimes simply referred to as "adjacent"), allowing the slab to bear a heavy load. Furthermore, even if the temporary construction support is installed in a misaligned position, the supporting force of the temporary construction support will reach at least one rebar. This makes it possible to prevent punch shear failure.

[0012] 17, for the lower base plate 13, the range of the punching shear p11 expands downward from the upper surface of the slab 72, and the bottom end reinforcements 70a, 70b, and 70c of the slab 70 are not generally omitted, so unless the conditions are extremely adverse, it is thought that the adjacent multiple reinforcing bars 70a, 70b, and 70c will fall within the range of the punching shear p11. For this reason, for reasons of appearance, etc., it is preferable that the lower base plate has the same configuration as the upper base plate, but it is thought that there will be few problems even if they are not exactly the same configuration.

[0013] Furthermore, when the lower base plate and at least the upper base plate are referred to as being rectangular, this means that they are rectangular when viewed from the bottom or in a plan view. However, they do not need to be precisely rectangular; they need only be roughly rectangular. This also includes cases where the corners of the rectangle are chamfered or the entire outer edge is curved or bent to make the outer edge concave or convex when viewed from the bottom or in a plan view (the same applies to the following inventions). Furthermore, when the corners of the lower base plate or upper base plate are chamfered or otherwise processed, the diagonal of the rectangular lower base plate or upper base plate is intended to be the dimension excluding the chamfered area. In other words, if the corners are chamfered, the diagonal dimension will be shorter by that amount (the same applies to the following inventions).

[0014] The invention of a support for temporary work used in the method for installing a support for temporary work according to the present invention will also be described below.

[0015] The temporary construction support of the present invention is a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper pipe portion and an upper base plate provided at the upper end of the upper pipe portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of adjacent parallel reinforcing bars can fit within the punching shear range of the slab.

[0016] According to the temporary construction support of the present invention, by optimizing the sizes of the lower base plate and the upper base plate, it is possible to achieve the same effects as the above-mentioned method of installing the temporary construction support.

[0017] The temporary construction support of the present invention is A temporary construction support erected between the upper and lower slabs of a building to be demolished, a lower column including a lower pipe portion, a lower base plate provided at a lower end of the lower pipe portion, and a lower pipe engaging portion provided at an upper end of the lower pipe portion; an adjusting nut rotatably engaged with the lower pipe engaging portion; a threaded pipe including a male threaded portion provided on an outer peripheral surface, a pin receiving cylindrical portion provided above the male threaded portion, and a first pin hole penetrating from one outer periphery to the other outer periphery of the pin receiving cylindrical portion in a direction perpendicular to the axis, the male threaded portion being threadedly engaged with the adjustment nut and the lower portion of the male threaded portion being inserted into the lower pipe portion; A rotation prevention portion that prevents the threaded pipe from rotating relative to the lower column; an upper pipe portion, an upper base plate provided at the upper end of the upper pipe portion, and a plurality of second pin holes provided at predetermined distances in the axial direction of the upper pipe portion and penetrating from one outer periphery to the other outer periphery in a direction perpendicular to the axis, the lower part of which is inserted into the threaded pipe; A support pin that passes through the first pin hole and the second pin hole continuously to fix the threaded pipe and the upper column, The wall thickness of the pin receiving cylinder portion of the threaded pipe is configured to be 8 mm or more and 9 mm or less, and the inner diameter of the threaded pipe is the same from the lower end to the upper end, The gap between the outer surface of the upper tube portion and the inner surface of the threaded tube is 3 mm or less, The size of the lower base plate and the upper base plate is configured so that a plurality of adjacent parallel reinforcing bars can fit within the punching shear range of the slab.

[0018] According to the temporary construction support of the present invention, the load-bearing capacity of the temporary construction support itself is excellent. Also, as with the above invention, the bearing force can be extended to multiple adjacent rebars, supporting a wide area, and the occurrence of punch shear failure can be suppressed. Therefore, the bearing capacity of each temporary construction support can be increased, and the number of temporary construction supports installed can be reduced. [Effects of the Invention]

[0019] As described above, according to the method for installing supports for temporary construction of the present invention, the occurrence of punching shear damage can be suppressed by optimizing the positioning of the lower base plate or the upper base plate. [Brief explanation of the drawings]

[0020] [Figure 1] 1A and 1B are a front view and a side view of a support for temporary construction work according to one embodiment of the present invention. [Figure 2] FIG. 1 is a front assembly view of the temporary construction support. [Figure 3] FIG. 1 is a side assembly view of a support for temporary construction work. [Figure 4] 1A and 1B are a plan view, a front view, and a side view of a threaded pipe. [Figure 5] 1A and 1B are a plan view, a front view, and a side view of a conventional threaded pipe. [Figure 6] 3A and 3B are a front view and a side view of a support pin. [Figure 7] 10 is a diagram illustrating the gap between the outer surface of the upper tube portion and the inner surface of the threaded pipe. FIG. [Figure 8] 10 is a table showing load test results, etc. [Figure 9] 10 is a diagram illustrating the dimensions of the upper pipe portion, the threaded pipe, and the lower pipe portion, and the gap between the outer surface of the upper pipe portion and the inner surface of the threaded pipe. FIG. [Figure 10] 10A and 10B are diagrams illustrating a conventional punching shear for an upper base plate. [Figure 11] FIG. 10 is a diagram illustrating the dimensions of the upper base plate. [Figure 12]10A and 10B are diagrams illustrating a punching shear using an upper base plate according to the present embodiment. [Figure 13] 10 is a diagram illustrating a state in which the outer edge of the upper base plate is arranged at an angle relative to multiple adjacent parallel reinforcing bars. FIG. [Figure 14] 14 is a diagram illustrating punching shears on main reinforcement bars in the installation state of the upper base plate shown by the solid line in FIG. 13. FIG. [Figure 15] 14 is a diagram illustrating punching shears for reinforcing bars in the installation state of the upper base plate shown by the solid line in FIG. 13. FIG. [Figure 16] 10A and 10B are diagrams illustrating other embodiments of the upper base plate or the lower base plate. [Figure 17] 10A and 10B are diagrams illustrating a punching shear for a lower base plate. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of a method for installing a temporary work support according to the present invention and an embodiment of a temporary work support 1 used in the method for installing a temporary work support will be described in detail with reference to the accompanying drawings.

[0022] First, we will explain an embodiment of the temporary work support 1. As shown in Figures 1 to 3, the temporary work support 1 of this embodiment includes a lower column 10, an adjusting nut 20, a threaded pipe 30, a rotation prevention part 40, an upper column 50, and support pins 60a and 60b.

[0023] The lower column 10 is a cylindrical member that constitutes the lower side of the temporary construction support 1 and includes a lower pipe portion 11, a lower pipe locking portion 12, and a lower base plate 13. The lower pipe portion 11 is a hollow cylindrical member. The lower pipe locking portion 12 is provided at the upper end of the lower pipe portion 11 and has a flange-like shape with a larger diameter than the lower pipe portion 11. The lower pipe locking portion 12 may be provided at any position where it can lock the adjustment nut 20. Here, the "upper end" is intended to include the vicinity of the upper end. The dimensions of the lower pipe portion 11 are an outer diameter of 114.3 mm and a wall thickness of 3.5 mm, or an outer diameter of 114 mm and a wall thickness of 4 mm. This is because there are generally products with measurements in tenths of a millimeter (or in tenths of a millimeter standard, the same applies below) and products with measurements in full millimeters (or in full millimeter standard, the same applies below). Therefore, the two are considered to be essentially the same.

[0024] The lower base plate 13 is provided at the lower end of the lower tube portion 11, and is generally rectangular in plan view, with a lower hole (not shown) in the center of its wide surface. Details of the lower base plate 13 will be described later. Note that the shape of the lower base plate is not limited to the one described above, and various shapes can be used, such as a lower base plate with chamfered corners, or a polygonal or circular shape other than a rectangle in plan view (the same applies to the upper base plate 52).

[0025] The adjusting nut 20 is rotatably engaged with the lower pipe engaging portion 12 provided at the upper end of the lower column 10, and includes a female threaded pipe 21, a nut engaging portion 23, and a handle 25. The female threaded pipe 21 is a cylindrical member with a female thread portion 22 (see FIG. 2) provided on its inner peripheral surface. The nut engaging portion 23 is provided on the outer periphery of the female threaded pipe 21 and includes a recess 24 that faces horizontally in front and rear views. The recess 24 engages with the lower pipe engaging portion 12, thereby enabling the adjusting nut 20 to rotate. The handle 25 is journaled by the nut engaging portion 23 so as to be rotatable in the vertical direction (see arrow a in FIG. 1(A)). The adjusting nut 20 is rotated by lifting the handle 25 and turning it horizontally.

[0026] The threaded pipe 30 is a substantially cylindrical member with a male thread portion 31 on its outer circumferential surface. Above the male thread portion 31, a pin receiving cylinder portion 34 and first pin holes 33a, 33b are provided. The male thread portion 31 is provided on the outer circumferential surface of the threaded pipe 30. This male thread portion 31 is threadedly engaged with the female thread portion 22 of the adjusting nut 20. Furthermore, the lower portion of the threaded pipe 30 is inserted into the lower pipe portion 11 of the lower column 10. When the adjusting nut 20 is rotated, the threaded pipe 30 moves vertically. The pin receiving cylinder portion 34 prevents the upper portion of the threaded pipe 30 from descending below the adjusting nut 20. The pin receiving cylinder portion 34 is also provided with first pin holes 33a, 33b that penetrate from one outer periphery to the other in a direction perpendicular to the axis of the threaded pipe 30. Two sets of first pin holes 33a, 33b are provided, arranged perpendicular to each other and offset vertically. As a result, the upper first pin hole 33a is located at the upper end of the pin receiving cylindrical portion 34, and has a semicircular shape in side view. The dimensions of this threaded pipe 30 will be described later.

[0027] The anti-rotation portion 40 prevents the threaded pipe 30 from rotating relative to the lower column 10. In this embodiment, the anti-rotation portion 40 includes a bolt hole 41 provided in the lower tube portion 11 and penetrating its outer periphery, a fixing nut 42 coaxial with the bolt hole 41 and joined to the outer periphery of the lower tube portion 11 by welding or the like, a fixing bolt 43 threadedly engaged with the fixing nut 42, and an elongated hole 44 provided axially on the outer periphery of the threaded pipe 30. When the lower part of the threaded pipe 30 is inserted into the lower column 10 and the bolt hole 41 is aligned with the elongated hole 44, the fixing bolt 43 is threaded into the fixing nut 42, and the shaft portion of the fixing bolt 43 is inserted into the elongated hole 44 of the threaded pipe 30. This allows the threaded pipe 30 to move up and down but prevents it from rotating relative to the lower pipe. In addition to the above, known configurations can be adopted as anti-rotation portions, although not shown in the figure, such as providing a key protruding from the inner surface of the lower tube portion 11 and providing a key groove corresponding to the key in the threaded tube 30.

[0028] The upper column 50 is a cylindrical member that constitutes the upper side of the temporary work support 1 and includes an upper pipe section 51, an upper base plate 52, and second pin holes 55a and 55b. The upper pipe section 51 is a hollow, approximately cylindrical member, and its lower portion is inserted into the threaded pipe 30 and the lower pipe section 11. Depending on its length and the extension length of the temporary work support 1 when in use, most of the upper pipe section 51 may be inserted into the threaded pipe 30 and the lower pipe section 11. The dimensions of the upper pipe section 51 are an outer diameter of 82.6 mm and a wall thickness of 6.0 mm, or an outer diameter of 83 mm and a wall thickness of 6 mm. This is because there are generally products that are marked in tenths of a millimeter and products that are marked in full millimeters, and the two are considered to be essentially the same (the same applies to the threaded pipes described below).

[0029] The upper base plate 52 is provided at the upper end of the upper tube portion 51, and like the lower base plate 13, is substantially rectangular in plan view and has an upper hole (not shown) in the center of its wide surface. The dimensions of this upper base plate 52 will also be described later.

[0030] The second pin holes 55a, 55b are provided in plurality at a predetermined distance in the axial direction of the upper tube portion 51, and are holes that penetrate from one outer periphery to the other outer periphery in a direction perpendicular to the axis of the upper tube portion 51. Two sets of second pin holes 55a, 55b are provided, and are arranged in perpendicular directions and offset vertically. The second pin holes 55a, 55b are provided to correspond to the first pin holes 33a, 33b provided in the threaded pipe 30, and are configured so that the second pin holes 55a, 55b overlap with the first pin holes 33a, 33b when the lower pillar 10 is pulled out a predetermined length from the threaded pipe 30 and the lower pillar 10.

[0031] The support pins 60a, 60b pass continuously through the first pin holes 33a, 33b in the threaded pipe 30 and the second pin holes 55a, 55b in the upper pipe section 51 while overlapping each other, thereby securing the threaded pipe 30 and the upper post 50. As shown in FIGS. 6(A) and 6(B), the support pins 60a, 60b have a pair of anti-slip protrusions 61 on the side surface of the pin at the tip end. The protrusions 61 have a semispherical shape protruding from the side surface of the pin. When the support pins 60a, 60b are normally inserted into the first pin holes 33a, 33b and the second pin holes 55a, 55b, the anti-slip protrusions 61 protrude from the side surface of the pin due to a spring (not shown) inside the support pins 60a, 60b, preventing them from coming out of the first pin holes 33a, 33b and the second pin holes 55a, 55b.

[0032] On the other hand, when inserting or removing the support pins 60a, 60b, the retaining projections 61 are retracted by external force to the same position as the pin side, allowing the support pins 60a, 60b to be inserted or removed from the first pin holes 33a, 33b and the second pin holes 55a, 55b. This external force also includes the retaining projections 61 being pushed in by abutting against the inner circumferential surfaces of the first pin holes 33a, 33b and the second pin holes 55a, 55b. In this embodiment, ball lock pins are used for the support pins 60a, 60b and the retaining projections 61. The bases of the support pins 60a, 60b are provided with support pin holes 62 for fastening an annular member 63, such as a triangular or round ring. The annular member 63 also serves as a stopper that prevents the support pins 60a, 60b from being inserted deeper into the first pin holes 33a, 33b and the second pin holes 55a, 55b.

[0033] Two sets of support pins 60a, 60b are provided, and the first pin holes 33a, 33b and the second pin holes 55a, 55b are arranged so that the two support pins 60a, 60b are inserted crossing each other.

[0034] Next, we will explain the unique configuration of the support for temporary work 1 of this embodiment, mainly with respect to the threaded pipe 30. As shown in FIGS. 4A to 4C, in the support for temporary work 1 of this embodiment, the wall thicknesses t1 and t2 of the threaded pipe 30 are preferably greater than or equal to 6 mm of the wall thickness of the upper pipe portion 51. Specifically, the pipe material used for the threaded pipe 30 is 101.6 mm in outer diameter and 8.0 mm in thickness for products measured in tenths of a millimeter, and 102 mm in outer diameter and 8 mm in thickness for products measured in full millimeters. The pin receiving tube portion 34 requires only the first pin holes 33a and 33b to be machined, and no thread machining is required, so the wall thickness t1 here remains 8 mm. Furthermore, the wall thickness t2 of the male thread portion 31 is thinned by machining the male thread portion 31, and in this embodiment, it is 6 mm, slightly thinner than the pin receiving tube portion 34. This is essentially the same as the wall thickness of the upper pipe portion 51, 6 mm. As a result, the width w1 where the first pin holes 33a, 33b contact the support pins 60a, 60b is increased, and the wall thickness t2 of the male threaded portion 31 is also increased, improving strength. When increasing the wall thickness of a pipe material, it is generally increased toward the inner diameter. Therefore, the outer diameter of the threaded pipe 30 remains unchanged, and only the inner diameter changes. This narrows the gap s between the inside of the threaded pipe 30 and the outside of the upper pipe portion 51, as shown in Figure 7. Furthermore, because the outer diameter of the threaded pipe 30 remains unchanged, the lower column 10 and adjusting nut 20 commonly used for temporary construction support can be used as is.

[0035] Next, a conventional threaded pipe 530 shown in Figures 5(A) to 5(C) will be described. In the conventional product, the threaded pipe 530 is made of a thinner pipe material than that used in this embodiment. Therefore, the thickness t5 of the pin receiving cylinder portion 534 is thin, and the width w3 where the first pin holes 533a, 533b contact the support pins 60a, 60b is narrow. Furthermore, the thickness t6 of the male threaded portion 531 is thinner than the thickness of the upper tube portion 51. Specifically, in a product measured to the nearest tenth of a millimeter, the outer diameter of the threaded pipe 530 (pin receiving cylinder portion 534) is 101.6 mm, the thickness t5 of the pin receiving cylinder portion 534 is 7.0 mm, and the thickness t6 of the male threaded portion 531 is 5.0 mm, thinned by machining (measured by the applicant). Furthermore, in a product marked in 1 mm increments that is substantially the same as the above product marked in tenths of a millimeter, the outer diameter of the threaded pipe 530 (pin receiving cylinder portion 534) is 102 mm, the thickness t5 of the pin receiving cylinder portion 534 is 7 mm, and the thickness t6 of the male threaded portion 531 is thinned to 5 mm by cutting. This not only makes the support pins 60a, 60b and the male threaded portion 531 more susceptible to deformation when a load is applied, but also widens the gap s (see Figure 7) between the inside of the threaded pipe 530 and the outside of the upper tube portion 51, making the threaded pipe 530 or upper tube portion 51 more susceptible to breakage.

[0036] The wall thicknesses of the above-described threaded pipe 30 and threaded pipe 530 are summarized with reference to Figure 8(A). As shown in Figure 8(A), in the threaded pipe 30 of this embodiment, the wall thickness t1 of the pin receiving cylinder portion 34 is 8 mm, which is 2 mm thicker than the wall thickness of the upper tube portion 51, which is 6 mm, and the wall thickness t2 of the male thread portion 31 is also 6 mm. In the conventional threaded pipe 530, the wall thickness t5 of the pin receiving cylinder portion 534 is 7 mm, which is 1 mm thicker than the wall thickness of the upper tube portion 51, and the wall thickness t6 of the male thread portion 531 is 5 mm, which is 1 mm thinner.

[0037] Next, referring to FIG. 8(B), the results of the strength test of the temporary work support will be explained. In this table, the CH32B (present embodiment) uses a threaded pipe 30, while the CH32 (conventional product) uses a threaded pipe 530. Furthermore, the lower column 10, adjusting nut 20, and upper column 50 are all identical. As a result, the maximum load at which the temporary work support buckles was 294 kilonewtons for the conventional product, while the temporary work support 1 according to this embodiment was 432 kilonewtons, a significant improvement. Furthermore, the allowable load for normal use, which is half the maximum load, was 147 kilonewtons for the conventional product, while the temporary work support 1 according to this embodiment was 216 kilonewtons.

[0038] The significant improvement in strength is likely due not only to the fact that the support pins 60a, 60b are less likely to bend, but also to the increased wall thicknesses t1, t2 of the threaded pipe 30, which improved the strength of the threaded pipe 30 itself, and to the narrowing of the gap s (see FIG. 7 ) between the threaded pipe 30 and the upper pipe section 51. Because there are gaps between the lower pipe section 11, the threaded pipe 30, and the upper pipe section 51, the area around the threaded pipe 30 forms a joint-like shape and deforms into a V-shape during a strength test. It is clear that the greater the degree of this V-shape bending, the weaker the strength of the temporary support. Eventually, the area around the threaded pipe 30 deforms, and the temporary support buckles. In the temporary support 1 of this embodiment, the increased wall thicknesses t1, t2 of the threaded pipe suppress the V-shape bending, and the threaded pipe 30 itself becomes less likely to bend, which is thought to improve its strength.

[0039] Next, referring to FIG. 9(A), the relationship between the wall thickness t1 of the threaded pipe 30 (pin receiving tube portion 34) and the gap s (see FIG. 7) between the inner surface of the threaded pipe 30 and the upper tube portion 51 will be explained. FIG. 9(A) shows the dimensions of the upper tube portion 51, the threaded pipe 30 (pin receiving tube portion 34), and the lower tube portion 11 for a conventional product indicated in tenths of a millimeter, a conventional product indicated in full millimeters, and the temporary work support 1 according to this embodiment (in full millimeters). The inner diameter of the threaded pipe shown in FIG. 9(A) can be easily calculated by multiplying the outer diameter of the threaded pipe by the wall thickness of the threaded pipe by 2. The gap s between the inner surface of the threaded pipe 30 and the upper tube portion 51 can be calculated as follows: ·Calculation formula Inner diameter of threaded pipe - outer diameter of upper pipe = clearance s Conventional product with tenths of a millimeter display 87.6mm-82.6mm=5mm Conventional product with 1mm unit display 88mm-83mm=5mm Temporary construction support 1 according to this embodiment 86mm-83mm=3mm As such, while the gap s of conventional products is 5 mm, the gap s of the temporary construction support 1 of this embodiment is 3 mm, which prevents the temporary construction support 1 from bending in a U-shape and improves its strength.

[0040] Next, referring to FIG. 9(B), the optimal range of the wall thickness of the threaded pipe 30 (pin receiving cylindrical portion 34) will be explained. As described above, when the wall thickness of the threaded pipe 30 (pin receiving cylindrical portion 34) is 8 mm, the gap s between the inner surface of the threaded pipe 30 and the outer surface of the upper tube portion 51 is 3 mm. In principle, the wall thickness of the threaded pipe 30 (pin receiving cylindrical portion 34) can be increased to 9.5 mm, at which point the gap s becomes 0 mm. However, due to the possibility of foreign matter such as rubble or dust entering the gap s between the inner surface of the threaded pipe 30 and the outer surface of the upper tube portion 51, the possibility of scratches or other imperfections on the inner surface of the threaded pipe 30 and the outer surface of the upper tube portion 51, and the possibility of irregularities occurring due to manufacturing tolerances for the threaded pipe 30, it is not practical to set the gap s to 0 mm. For this reason, it is preferable to set the gap s to 3 mm or less and 1 mm or more. In this case, the wall thickness t1 of the threaded pipe 30 (pin receiving barrel portion 34) is 8 mm or more and 9 mm or less, and the wall thickness t2 of the male thread portion 31 is reduced by cutting and is therefore 6 mm or more and 7 mm or less. Also, compared to the wall thickness of the upper tube portion 51, which is 6 mm, the wall thickness of the threaded pipe 30 (pin receiving barrel portion 34) is thickened in the range of 2 mm or more and 3 mm or less, and the wall thickness of the male thread portion 31 is thickened in the range of 0 mm or more and 1 mm or less.

[0041] Furthermore, by limiting the gap s to 2 mm or more and 3 mm or less, the movement of the threaded pipe 30 and the upper tube portion 51 is less likely to be hindered even if foreign matter such as rubble or dust gets into the gap s. In this case, the wall thickness t1 of the threaded pipe 30 (pin receiving barrel portion 34) is 8 mm or more and 8.5 mm or less, and the wall thickness t2 of the male thread portion 31 is 6 mm or more and 6.5 mm or less. Also, compared to the wall thickness of the upper tube portion 51, which is 6 mm, the wall thickness of the threaded pipe 30 (pin receiving barrel portion 34) is thicker in the range of 2 mm or more and 2.5 mm or less, and the wall thickness of the male thread portion 31 is thicker in the range of 0 mm or more and 0.5 mm or less.

[0042] On the other hand, by limiting the gap s to less than 2 mm and equal to or greater than 1 mm, the gap s becomes narrower and the wall thickness of the threaded pipe 30 becomes thicker, which is expected to further improve the strength of the temporary work support 1. In this case, the wall thickness t1 of the threaded pipe 30 (pin receiving cylindrical portion 34) is greater than 8.5 mm and equal to or less than 9 mm, and the wall thickness t2 of the male thread portion 31 is greater than 6.5 mm and equal to or less than 7 mm. Furthermore, compared to the wall thickness of the upper tube portion 51, which is 6 mm, the wall thickness of the threaded pipe 30 (pin receiving cylindrical portion 34) is thicker in the range of greater than 2.5 mm and equal to or less than 3 mm, and the wall thickness of the male thread portion 31 is thicker in the range of greater than 0.5 mm and equal to or less than 1 mm.

[0043] As mentioned above, these gaps s depend on the wall thickness (inner diameter) of the threaded pipe 30 and the outer diameter of the upper pipe portion 51. For this reason, it is thought that there may be variations in the order of one-tenth of a millimeter due to tolerances, etc., during the manufacturing of the pipe material.

[0044] Next, the lower base plate 13 and the upper base plate 52 of the temporary work support 1 of this embodiment will be described with reference to Figures 10 to 16. As already mentioned, punching shear failure is likely to occur when a force that pushes up from below is applied by the upper base plate 52 to a location where upper end reinforcement (not shown), such as the center of the slab 72, is omitted. For this reason, the upper base plate 52 will be mainly described here, but there is no particular problem with the lower base plate 13 having the same configuration as the upper base plate 52. For the punching shear of the lower base plate 13, please refer to Figure 17. In Figure 10 and subsequent figures, reinforcing bars with a diameter of 9 mm are shown.

[0045] First, referring to Figure 10, we will explain punching shear using an upper base plate 52z supported by a conventional temporary construction support. As previously mentioned, the center-to-center distance between adjacent main reinforcements 70a, 70b, and 70c should ideally be 200 mm or less. However, in the 1950s and 1960s, in order to reduce the amount of reinforcing bars used, the center-to-center distance between adjacent main reinforcements 70a, 70b, and 70c was increased, as long as it did not pose a problem in structural calculations, for buildings with relatively light live loads such as residential buildings. This center-to-center distance was, for example, 210 mm or 220 mm. In addition, the cover thickness of the reinforcing bars 70a, 70b, and 70c was also 20 mm in some buildings. Furthermore, in older buildings, the slab 72 is often relatively thin, at 120 mm, which is another factor that makes punching shear failure more likely.

[0046] Therefore, when the center distance between adjacent main reinforcements 70b, 70c becomes 210 mm or 220 mm, the main reinforcements 70b, 70c may fall outside the range of the punching shear force p10 applied by the upper base plate 52z. Even if the center distance between adjacent main reinforcements 70a is 200 mm, some of the main reinforcements 70a may fall outside the range of the punching shear force p10 applied by the upper base plate 52z. This situation increases the risk of punching shear damage occurring when heavy machinery passes over the slab 72.

[0047] Therefore, in the temporary construction support 1 of this embodiment, as shown in FIG. 11 , the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g are generally rectangular (square) in plan view, with the length of each side being 170 mm or more and 200 mm or less, or 140 mm or more and less than 170 mm. The corners 56 of these upper base plates 52a, 52b, 52c, 52d, 52d, 52e, 53f, and 52g may or may not be chamfered. Here, when the corners 56 are chamfered, C10 chamfering is used. Note that FIGS. 11 and 13 omit the upper punched holes provided in the centers of the wide surfaces of the upper base plates 52a, 52b, 52c, and 52d. FIG. 13 is a perspective view of the upper base plate 52a (52b, 52c, 52d, 52d, 52e, 53f, 52g) from below, showing the main reinforcement bars 70 and distribution reinforcement bars 71 in the slab.

[0048] Next, referring to FIG. 12, punching shears p1, p2, p3, and p4 will be described for the upper base plates 52a, 52b, 52c, and 52d shown in FIG. 11, each having a side length of 170 mm to 200 mm, arranged so that their outer edges 57 are aligned along the main reinforcement bars 70 (as indicated by the dashed lines in FIG. 13). The cover thickness here is also 20 mm. As shown in the figure, if the center-to-center distance between the main reinforcement bars 70a is 200 mm, and the upper base plate 52a has a side length of 170 mm, multiple parallel adjacent reinforcing bars 70a will fall within the range of punching shear p1. Furthermore, if multiple parallel adjacent reinforcing bars 70a fall within the range of punching shear p1, even if the installation position of the temporary construction support 1 is shifted for some reason, at least one reinforcing bar 70a will fall within the range of punching shear p1 of the upper base plate 52a (the same applies to the following embodiments).

[0049] Furthermore, if the upper base plate 52b has a side length of 180 mm, multiple parallel adjacent reinforcing bars 70b can fit within the range of punching shear p2 even if the center-to-center distance between the main reinforcing bars 70b is 210 mm. Similarly, if the upper base plate 52c has a side length of 190 mm, multiple parallel adjacent reinforcing bars 70c can fit within the range of punching shear p3 even if the center-to-center distance between the main reinforcing bars 70c is 220 mm. Furthermore, if the upper base plate 52d has a side length of 200 mm, multiple parallel adjacent reinforcing bars 70c can fit within the range of punching shear p4 with ease even if the center-to-center distance between the main reinforcing bars 70c is 220 mm. In other words, when the outer edge 57 of the upper base plate is installed parallel to the reinforcing bars 70, the side length of the upper base plates 52a, 52b, 52c, and 52d is preferably 170 mm or more and 180 mm or less, more preferably more than 180 mm and 190 mm or less, and even more preferably more than 190 mm and 200 mm or less. For the same reason, it can be said that a distance of more than 200 mm and not more than 210 mm is even more preferable. However, if the dimensions of the upper base plates 52a, 52b, 52c, and 52d are made too large, it will cause problems in transportation and storage, so it is preferable to keep the distance not more than 210 mm.

[0050] Returning to FIG. 11, the diagonal dimensions of the upper base plates 52a, 52b, 52c, and 52d, each with a side length of 170 mm to 200 mm, will be described. For the upper base plate 52a with a side length of 170 mm, the diagonal length is 226 mm (rounded to the nearest whole number, the same applies below) when chamfered to C10, and 240 mm when not chamfered. For the upper base plate 52b with a side length of 180 mm, the diagonal length is 240 mm when chamfered to C10, and 255 mm when not chamfered. Furthermore, for the upper base plate 52c with a side length of 190 mm, the diagonal length is 255 mm when chamfered to C10, and 269 mm when not chamfered. Furthermore, in the case of the upper base plate 52d having a side length of 200 mm, the length of the diagonal line is 269 mm when chamfered to C10, and 283 mm when not chamfered.

[0051] Also referring to Figure 11, the diagonal lengths of upper base plates 52e, 52f, and 52g, each with a side length of 140mm to 160mm, will be described. For upper base plate 52e with a side length of 140mm, the diagonal length is 184mm when chamfered to C10 and 198mm when not chamfered. For upper base plate 52f with a side length of 150mm, the diagonal length is 198mm when chamfered to C10 and 212mm when not chamfered. Furthermore, for upper base plate 52g with a side length of 160mm, the diagonal length is 212mm when chamfered to C10 and 226mm when not chamfered.

[0052] A situation will be described where the outer edges 57 of these upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g are disposed at an angle to the plurality of adjacent parallel reinforcing bars 70 and 71, as shown by the solid lines in Fig. 13. This means that the diagonals of the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g are disposed in a direction that is approximately perpendicular to the plurality of adjacent parallel reinforcing bars 70 and 71 in a plan view or bottom view.

[0053] Among these, punching shears p20, p21, p22, p5 on adjacent parallel main reinforcements 70a, 70b, 70c when the outer edges 57 of the upper base plates 52e, 53f, 52g, each with a side length of 140 mm to 160 mm, are arranged diagonally will be described with reference to Figure 14. The center distance between the main reinforcements, the thickness of the slab 72, and the cover thickness here are the same as those in Figure 10.

[0054] As shown in Figure 14, when an upper base plate 52e with a diagonal length of 184 mm is used, pieces with a center-to-center distance between adjacent parallel main reinforcements 70b of up to 210 mm can be accommodated within the range of the punching shear p20. Furthermore, when upper base plates 52e and 52g with a diagonal length of 198 mm are used, pieces with a center-to-center distance between adjacent parallel main reinforcements 70c of up to 220 mm can be accommodated within the range of the punching shear p21. Here, multiple upper base plates with the same diagonal dimensions are selected because some have chamfered corners 56 and others do not, and the diagonal dimensions differ (same below). Furthermore, by using upper base plates 52f and 52g with a diagonal length of 212 mm or more, pieces with a center-to-center distance between adjacent parallel main reinforcements 70c of 220 mm can be accommodated within the range of the punching shears p22 and p5 with ample margin. The upper base plate 52g of a typical temporary construction support 1 has a side length of 160 mm and C10 chamfered corners 56. In this case, the diagonal length is 212 mm, and by arranging the outer edges 57 at an angle to the main reinforcement 70, it can easily accommodate construction sites where the center distance between adjacent parallel main reinforcement 70c is 220 mm. Although not explained further, if upper base plates 52a, 52b, 52c, and 52d with a side length of 170 mm to 200 mm and a diagonal length of 226 to 283 mm are used, it is clear that the main reinforcement 70 can be placed within the punching shear range with even more leeway.

[0055] Next, punching shears for distribution reinforcement 71 when the outer edges 57 of upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g are installed at an angle will be described with reference to Fig. 15. Fig. 15 is a diagram illustrating punching shears p5, p6, p7, p8, p9, p20, p21, and p22 for distribution reinforcement 71a, 71b, 71c, 71d, 71e, 71f, 71g, and 71h placed on main reinforcement 70 arranged in the left-right direction of the figure.

[0056] First, we will explain punching shears p5, p6, p7, p8, and p9 when using upper base plates 52a, 52b, 52c, and 52d with sides between 170 and 200 mm. As shown in Figure 15, when using upper base plate 52a (see Figure 11) with a diagonal dimension of 226 mm, punching shear p5 can accommodate structures with a center-to-center distance between adjacent parallel distribution bars 71c of up to 270 mm. Furthermore, when using upper base plates 52a and 52b with a diagonal dimension of 240 mm, punching shear p6 can accommodate structures with a center-to-center distance between adjacent parallel distribution bars 71e of up to 290 mm. Furthermore, when using upper base plates 52b and 52c with a diagonal dimension of 255 mm, punching shear p7 can accommodate structures with a center-to-center distance between adjacent parallel distribution bars 71f of up to 300 mm. Furthermore, when upper base plates 52c, 52d with diagonal dimensions of 269 mm and 283 mm are used, parallel adjacent distribution bars 71f with a center-to-center distance of 300 mm can be easily accommodated within the range of punching shears p8, p9. In other words, when the center-to-center distance between distribution bars is 270 mm or more, it is preferable to use an upper base plate with a diagonal length of 226 mm or more and 240 mm, more preferably one that exceeds 240 mm and is 255 mm or less, and even more preferably one that exceeds 255 mm and is 283 mm or less.

[0057] Next, we will explain the punching shears p20, p21, p22, and p5 for reinforcing bars when using upper base plates 52e, 52f, and 52g with sides between 140 and 160 mm. As shown in Figure 15, when using upper base plate 52e with a diagonal dimension of 184 mm, reinforcing bars 71g with a center-to-center distance of up to 230 mm can be included in the range of punching shear p20. Furthermore, when using upper base plates 52e and 52f with a diagonal dimension of 198 mm, reinforcing bars 71h with a center-to-center distance of up to 240 mm can be included in the range of punching shear p21. Furthermore, when using upper base plates 52f and 52g with a diagonal dimension of 212 mm, reinforcing bars 7b with a center-to-center distance of up to 260 mm can be included in the range of punching shear p22. For the punching shear p5 of the upper base plate 52g having a side length of 160 mm and an unchamfered diagonal length of 226 mm, please refer to the above explanation.

[0058] Here, we will explain the center-to-center distance between adjacent distribution bars 71a, 71b, 71c, 71d, 71e, 71f, 71g, and 71h. Regulations stipulate that the center-to-center distance between distribution bars must be 300 mm or less, and in older buildings, distribution bars are often arranged at 250–300 mm. In more recent buildings, the same distance as the main bars, 200 mm, is sometimes used. By arranging the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g diagonally as shown by the solid lines in Figure 13, depending on the conditions, a total of four rebars—two adjacent main bars 70 and two adjacent distribution bars 71 that cross them—can be accommodated within the punching shear of the upper base plate. Furthermore, even if the position of the upper base plate is shifted, there is a high probability that multiple reinforcing bars 70, 71 can be placed within the range of the punching shears p5, p6, p7, p8, p9, p20, p21, and p22, and no matter how much the position is shifted, at least one reinforcing bar can be placed within the range of the punching shears.

[0059] Next, upper base plates 52h and 52j according to another embodiment will be described with reference to Figures 16(A) and 16(B). Figure 16(A) will be described first. The upper base plate 52h of this embodiment has a generally elliptical shape in plan or bottom view. The length L1 of an imaginary line vl1 passing through the wide surface ws and the center c of the upper base plate 52h from one end 58h to the other end 59h is set to be 184 mm or more but less than 226 mm, or 226 mm or more but 283 mm or less.

[0060] The upper base plate 52j shown in FIG. 16(B) has a generally octagonal shape with some sides curved inward in plan or bottom view. The length L2 of an imaginary line vl2 passing through the wide surface ws and the center c of the upper base plate 52j is 184 mm or more but less than 226 mm, or 226 mm or more but less than 283 mm, from one end 58j2 to the other end 59j2. This upper base plate 52j may also have an imaginary line vl3 connecting one end 58j3 and the other end 59j3. In this upper base plate 52j, it is preferable to arrange the imaginary line vl2 or vl3 perpendicular to the reinforcing bar 70 (in the figure, the imaginary line vl2 is perpendicular to the reinforcing bar 70). This is because the wide surface of the upper base plate 52j exists on both sides of the imaginary lines vl2 and vl3 in plan view at the ends of the upper base plate 52j, allowing for a wide punching shear force to be applied to the reinforcing bar 70. Alternatively, imaginary lines vl4 and vl5 connecting one end 58j4 and 58j5 with the other end 59j4 and 59j5 may be used.

[0061] When these upper base plates 52h, 52j are arranged such that their imaginary lines intersect perpendicularly with the reinforcing bars 70 (71) in a plan view or bottom view, if the lengths L1, L2 of the imaginary lines vl1, vl2 of the upper base plates 52h, 52j are 184 mm or more and less than 226 mm, they can exert a bearing force equivalent to that of the punching shears p20, p21, p22 shown in Figures 14 and 15. Furthermore, by setting the lengths L1, L2 of the imaginary lines vl1, vl2 to 226 mm or more and 283 mm or less, the upper base plates 52h, 52j can exert a bearing force equivalent to that of the punching shears p5, p6, p7, p8, p9 shown in Figure 15. This allows at least a plurality of adjacent reinforcing bars 70 (71) to be included within the range of the punching shears. The shape of the upper base plates is not limited to the above-described shape, and various shapes such as circles, diamonds, and other polygons can be used. The length of the imaginary lines vl3, vl4, and vl4 is considered in the same way as that of the imaginary lines vl1 and vl2.

[0062] Next, a description will be given of an embodiment of a method for installing a temporary work support using the above-mentioned temporary work support 1. The method for installing a temporary work support of this embodiment includes a positioning step and an installation step.

[0063] The positioning process is a process of determining the positions of the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g and the lower base plate 13 of the temporary construction support based on the reinforcement drawing of the building to be demolished. At this time, it is preferable that the plurality of parallel adjacent reinforcing bars 70a, 70b, and 70c are within the punching shear range of the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g relative to the slab 72. These parallel adjacent reinforcing bars 70a, 70b, and 70c are preferably main reinforcements 70, and it is further preferable that at least one, and preferably two, of the distribution reinforcements 71 intersecting the main reinforcements 70 be within the punching shear range of the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g. By positioning the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g in this way, it is possible to fit three reinforcing bars, or four reinforcing bars under favorable conditions, within the range of the punching shear. At this time, it is preferable to position the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g on the assumption that the outer edges 57 of the upper base plates 52a, 52b, 52c, 52d, 52e, 53f, and 52g are arranged at an angle of approximately 45 degrees to the adjacent reinforcing bars 70 and 71, as shown by the solid lines in Figure 13.

[0064] Furthermore, when using the upper base plates 52h, 52j shown in Figures 16(A) and (B), it is preferable to position them on the premise that the imaginary lines vl1, vl2, etc. are arranged in a direction perpendicular to the main reinforcement 70 in a plan view.

[0065] Next, in the installation process, the temporary support is installed at the position determined in the positioning process. In this case, when the upper base plates 52a, 52b, 52c, and 52d have a side length of 170 mm or more and 200 mm or less, the outer edges 57 of the upper base plates 52a, 52b, 52c, and 52d may be arranged parallel to the reinforcing bars 70 and 71, as shown by the dashed lines in FIG. 13. However, to increase the bearing capacity of the temporary support 1 for the slab 72, it is preferable to arrange the outer edges 57 of the upper base plates 52a, 52b, 52c, and 52d at an angle to the parallel adjacent reinforcing bars 70 and 71, as shown by the solid lines in FIG. 13. By arranging them in this manner, a total of four parallel adjacent and intersecting main reinforcements 70 and distribution reinforcements 71 can be inserted in a "I" shape within the range of punching shear p5, p6, p7, p8, and p9 exerted by the corners 56 of the upper base plates 52a, 52b, 52c, and 52d on the slab 72. Furthermore, by installing them in this manner, it is possible to more reliably place a plurality of reinforcing bars within the ranges of the punching shears p5, p6, p7, p8, and p9 of the upper base plates 52a, 52b, 52c, and 52d.

[0066] Furthermore, when using upper base plates 52e, 52f, 52g with a side length of 140 mm or more and less than 170 mm, it is preferable to arrange the outer edges 57 of the upper base plates 52e, 52f, 52g at an angle to the reinforcing bars 70, 71. By arranging them in this manner, it is possible to place at least a plurality of adjacent main reinforcements 70 within the range of punching shear p20, p21, p22, p5 exerted by the corners 56 of the upper base plates 52e, 52f, 52g.

[0067] 16 is used, the imaginary lines vl1, vl2, etc. are arranged in a direction perpendicular to the main reinforcements 70. By arranging them in this way, at least a plurality of adjacent main reinforcements 70 can be placed within the range of punching shear p20, p21, p22, p5 (or p5, p6, p7, p8, p9) exerted by one end 58h, 58j2, 58j3, 58j4, 58j5 and the other end 59h, 59j2, 59j3, 59j4, 59j5 of the upper base plates 52h, 52j.

[0068] Furthermore, as already mentioned, the allowable load for normal use in temporary work supports is 147 kilonewtons for conventional products, while the allowable load for the temporary work support 1 according to this embodiment is 216 kilonewtons. From these values, 147 / 216 = approximately 0.68, which means that the number of temporary work supports 1 installed can be reduced to approximately 68% of that of conventional products. This is because, even if the upper base plate of a conventional temporary work support is appropriately sized and positioned, it is possible to reduce the likelihood of punching shear failure, but the allowable load of the temporary work support itself is low, making it difficult to reduce the number of temporary work supports installed. On the other hand, with the temporary work support 1 of the present invention, by appropriately sizing the upper base plate or positioning its outer edge at an appropriate angle relative to the rebar, punching shear failure is reduced, and the load that each temporary work support 1 can bear can be increased accordingly.

[0069] As described above, according to the temporary construction support and the installation method for the temporary construction support of this embodiment, by appropriately setting the size of the upper base plate or by arranging its outer edge at an appropriate angle relative to the rebar, it is possible to place multiple rebars within the range of the punching shear that the upper base plate exerts on the slab. Even if the upper base plate is misaligned, at least one rebar can be placed. Furthermore, by arranging the outer edge of the upper base plate at an angle relative to the rebar, the rebar can be more reliably placed within the range of the punching shear. These features make punching shear failure less likely to occur, improving safety during demolition work. Even if punching shear failure does occur, the support force of the upper base plate is still applied to the rebar, so the progression of the failure is likely to be slow, making it more likely that there will be time to evacuate.

[0070] In addition, by increasing the thickness of the threaded pipe, the strength of the temporary construction support can be significantly improved, which in turn helps to prevent weight increases and reduce manufacturing costs.

[0071] Furthermore, by reducing the risk of punching shear damage and improving the strength of temporary construction supports, it is possible to reduce the number of supports that need to be installed per unit area, which will improve work efficiency and reduce work costs at construction sites.

[0072] The above-described temporary construction support and the method for installing the temporary construction support are examples of the present invention, and the configurations thereof can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0073] 1. Temporary construction support, 10··Lower column, 11··Lower pipe portion, 12··Lower pipe locking portion, 13··Lower base plate, 20. Adjusting nut, 21. Female thread pipe, 22. Female thread portion, 23. Nut locking portion, 24. Recess, 25. Handle, 30,530··Threaded pipe, 31,531··Male thread portion, 33a, 33b, 533a, 533b··First pin hole, 34,534··Pin receiving cylinder portion, 40: Anti-rotation portion, 41: Bolt hole, 42: Fixing nut, 43: Fixing bolt, 44: Oblong hole, 50··Upper column, 51··Upper tube portion, 52a, 52b, 52c, 52d, 52e, 53f, 52g, 52h, 52j, 52z··Upper base plate, 55a, 55b··Second pin hole, 56··Corner portion, 57··Outer edge, 58h, 58j··One end, 59h, 59j··Other end, ws··Wide surface, vl··Imaginary line, 60a, 60b: Support pin; 61: Pull-out prevention protrusion; 62: Support pin hole; 63: Annular member; 70, 70a, 70b, 70c··Main reinforcement (reinforcement), 71, 71a, 71b, 71c, 71d, 71e, 71f, 71g, 71h··Distribution reinforcement (reinforcement), 72··Slab, p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p20,p21,p22... Punching shear,

Claims

1. a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper tube portion and an upper base plate provided at the upper end of the upper tube portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be placed within the punching shear range of the slab, A method for installing a temporary construction support, wherein at least the upper base plate of the lower base plate and the upper base plate is rectangular and has a side length of 140 mm or more and less than 170 mm, a positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the outer edge of the upper base plate is arranged diagonally relative to the reinforcing bars based on a reinforcing bar arrangement drawing; A method for installing a temporary construction support, characterized in that the temporary construction support is installed based on the position determined in the positioning process, and the outer edge of the upper base plate is positioned at an angle to multiple adjacent parallel steel bars, so that the multiple adjacent parallel steel bars are installed within the range of the punching shear exerted by the corners of the upper base plate.

2. a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper tube portion and an upper base plate provided at the upper end of the upper tube portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be accommodated within the punching shear range of the slab, A method for installing a temporary work support, wherein at least the upper base plate of the lower base plate and the upper base plate is rectangular and has a diagonal length of 184 mm or more and less than 226 mm, a positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the outer edge of the upper base plate is arranged diagonally relative to the reinforcing bars based on a reinforcing bar arrangement drawing; A method for installing a temporary construction support, characterized in that the temporary construction support is installed based on the position determined in the positioning process, and the outer edge of the upper base plate is positioned at an angle to multiple adjacent parallel steel bars, so that the multiple adjacent parallel steel bars are installed within the range of the punching shear exerted by the corners of the upper base plate.

3. a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper pipe portion and an upper base plate provided at the upper end of the upper pipe portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be placed within the punching shear range of the slab, A method for installing a temporary construction support, wherein the length of an imaginary line passing through the wide surface of at least the upper base plate of the lower base plate and the upper base plate is 184 mm or more and less than 226 mm from one end to the other end, A positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the virtual line is arranged in a direction perpendicular to the reinforcing bars based on a reinforcing bar arrangement drawing; A method for installing a temporary construction support, characterized in that the temporary construction support is installed based on the position determined in the positioning process, and the virtual line is arranged in a direction perpendicular to multiple adjacent parallel steel bars, so that the multiple adjacent parallel steel bars are installed within the range of the punching shear exerted by one end and the other end of the upper base plate.

4. a lower column including a lower pipe portion and a lower base plate provided at a lower end of the lower pipe portion; an upper column including an upper pipe portion and an upper base plate provided at the upper end of the upper pipe portion; The upper pipe portion is inserted into the lower pipe portion, and the distance between the lower base plate and the upper base plate is adjustable. This is a temporary construction support that is erected between the upper and lower slabs of a building to be demolished, The size of the lower base plate and the upper base plate is configured so that a plurality of parallel adjacent reinforcing bars can be accommodated within the punching shear range of the slab, A method for installing a temporary construction support, wherein the length of an imaginary line passing through the wide surface of at least the upper base plate of the lower base plate and the upper base plate is 226 mm or more and 283 mm or less from one end to the other end, A positioning step of positioning the upper base plate so that a plurality of parallel adjacent reinforcing bars are within the range of punching shear exerted by the temporary construction support on the slab when the virtual line is arranged in a direction perpendicular to the reinforcing bars based on a reinforcing bar arrangement drawing; A method for installing a temporary construction support, characterized in that the temporary construction support is installed based on the position determined in the positioning process, and the virtual line is arranged in a direction perpendicular to multiple adjacent parallel steel bars, so that the multiple adjacent parallel steel bars are installed within the range of the punching shear exerted by one end and the other end of the upper base plate.

Images