JP2009287286A - Support for overhanging floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support which can dispense with both of a hanging chain and a strut material, which can reduce a tensile force applied in the length direction of a bolt, and which can hold a tread of a scaffold board for use in a worker's work in an approximately horizontal state. <P>SOLUTION: This support comprises a sleeper material 6 which is arranged on the downside of an overhanging portion 3a of a form so as to support the concrete form of an overhanging portion of a floor slab 2, provided in such a manner as to overhang from an upper flange portion 1b of a main girder 1, and a length-adjustable diagonal member 7 for supporting the sleeper material from an obliquely lower side. In the support, a through bolt or a pin is laterally inserted between an obliquely and vertically-long slot and a through-hole provided at one end of the sleeper material, via a retainer fitting provided with the obliquely and vertically-long slot with an upper end inclined in the center of web direction of the main girder; and thus, the sleeper material is attached to the retainer fitting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a support for supporting a projecting portion of a formwork for a concrete floor slab, which is provided by projecting from an upper flange portion of a main girder made of steel or concrete, when placing a concrete floor slab of a bridge from below. About.

  In bridges where roads are built, concrete floor slabs are used for the roadbed, but in order to support the concrete load and to fix the concrete floor slab formwork in place, two horizontal support beams are usually used. It spans between the standing main girders, and a concrete floor slab form is provided thereon, and a concrete floor slab is placed.

  In recent years, bridges on which roads and the like are built tend to reduce the number of main girders and increase the cross section of the concrete slab. As a result, the projecting dimension of the projecting part of the concrete floor slab form projecting from the upper flange part of the main girder is increased, and the thickness of the concrete floor slab is also thicker than that of the conventional bridge.

  Conventionally, a large pulling material disposed below the projecting part of the concrete floor slab formwork to support the projecting part of the concrete floor slab formwork projecting from the upper flange part of the main girder. (Also referred to as a lateral arm material), and a support work made of a diagonal material capable of adjusting the length of the large pulling material supported from obliquely below has been installed. A concrete floor slab form made of plywood or the like is provided on the upper part of the large pulling material that constitutes the support work, and the concrete floor slab including the overhanging portion is formed by pouring concrete onto it. It is formed.

  FIG. 1 is a cross-sectional view showing an example of a concrete floor slab of a bridge according to a conventional example.

  Here, steel main girders 1 and 1 are erected on the left and right, and a horizontal support beam 4 is provided between upper ends of pipe supports 5 and 5 installed inside the main girders 1 and 1, respectively. Is overlaid. The formwork 3 of the concrete floor slab 2 is supported by the two main girders 1 and 1, but the formwork 3 projects to the outside of the upper flange portion 1b of the two main girders 1 and 1. The part 3a is supported from below by a supporting work composed of a large pulling material 6 and an adjustable diagonal member 7 arranged below the portion 3a. That is, under the projecting portion 3a of the formwork, a large pulling material 6 is disposed via a joist material 9, and the large pulling material 6 has an upper flange 1b of the main girder 1 at one end thereof. It is suspended by suspension bolts 10 attached to the front end of each of them, and is supported from below by a diagonal member 7 whose length can be adjusted at the non-end. Furthermore, the lower end portion of the diagonal member 7 is attached to the corner portion between the lower end portion of the web 1a of the main girder 1 and the lower flange 1c so that the mounting angle is freely adjustable. A chain 8 is attached to the upper end of the web 1a of the main girder 1, and the diagonal member 7 is pulled in order to cancel the outward horizontal force generated by the load applied to the projecting portion 3a of the mold.

  A concrete floor slab is formed by placing concrete on a formwork supported by such two main girders and a supporting work installed outside thereof.

  FIG. 2 is an example (side view) of a support according to a conventional example installed outside the main girder.

  On the lower side of the projecting portion 3 a of the formwork of the concrete floor slab 2, a large pulling material 6 is arranged via a joist material 9. The large pulling material 6 is suspended at one end portion (left end portion in the figure) by a suspension bolt 10 attached to the distal end portion of the upper flange 1b of the steel main girder 1 via a flange connection piece 12. And is supported from below by a diagonal member 7 of adjustable length at the non-end. The lower end portion of the diagonal member 7 is attached to the corner portion between the lower end portion of the web 1a of the main girder 1 and the lower flange 1c so that the mounting angle is freely adjustable. Three attachment fittings 13 that can connect the upper end of the diagonal member 7 at any attachment angle are provided at the non-end portion of the large pulling member 6, and the upper end of the diagonal member 7 is attached to one of them. Further, a chain 8 is attached to the upper end of the web 1a of the main girder 1, and the diagonal member 7 is pulled in order to cancel the outward horizontal force (rightward in the figure) generated by the load applied to the projecting portion 3a of the formwork. ing.

  And the scaffolding board 15 for the worker 14 to work is installed in the upper side of the vicinity of the other end part (right end part in the figure) of the large pulling material 6. Further, in order to prevent the worker 14 from falling, a handrail column 16 and a handrail material 17 are attached to the other end portion (right end portion in the drawing) of the large pulling material 6.

  Patent Document 1 proposes a support work that expands the size of a projecting portion of a formwork from a steel main girder and can cope with the weight of a concrete slab. This makes it possible to adjust the length of the large pulling material placed under the overhang of the formwork, and to adjust the length via an inverted mountain-shaped truss structure provided under the large pulling material. It is supported by diagonal materials.

  FIG. 3 is a side view of the support construction proposed in Patent Document 1 and installed outside the main girder.

  Under the projecting portion 3a of the formwork of the concrete floor slab 2, one end portion (the left end portion in the figure) of the adjustable pulling material 6 via a joist material 9 is connected via a metal fitting 21. The steel main girder 1 is fixed to the side portion near the upper end of the web 1a. Here, a hole for inserting a bolt penetrating the web 1a is formed in the lateral direction, and the receiving metal 21 is fixed in the vicinity of the upper end portion of the web 1a by screwing with a bolt 22 and a nut. . An outward (rightward in the figure) horizontal force is generated by the load applied to the overhanging portion 3a of the mold, and this outward horizontal force is inwardly obtained by screwing the bolt 22 and nut (leftward in the figure). ) Is canceled by the horizontal force, and the lateral movement of the large pulling material is restricted.

  The length-adjustable pulling member 6 includes a rectangular tube-shaped outer cylinder member 6a and an inner cylinder member 6b that is inserted into the outer cylinder member 6a so as to be movable in the lateral direction. A plurality of holes are drilled at required intervals at the inner ends of the outer cylinder member 6a and the inner cylinder member 6b, and one pin is selected from each of the holes drilled in both the members 6a and 6b. The length of the pulling material 6 can be adjusted to a predetermined length by inserting (not shown) therethrough and fixing the positions of the members 6a and 6b.

  In addition, a fixed-length diagonal material 11 and a length-adjustable diagonal material 7 are provided in the vicinity of the left end portion of the outer cylinder member 6a, which is an adjustable length pulling material, and the non-end portion of the inner cylinder member 6b, respectively. The upper end of each of the two is pin-coupled, and the lower end of each of the fixed-length diagonal member 11 and the adjustable-length diagonal member 7 is pin-bonded to the bracket 18 to form an inverted mountain-shaped truss structure. Has been. In addition, the upper end part of the diagonal member 7 which comprises the inverted mountain-shaped truss structure and whose length can be adjusted is attached to the attachment metal fitting 13 provided in the inner cylinder member 6b so that attachment angle is free. Further, the inverted mountain truss structure is reinforced by a reinforcing rod 19 that connects the vicinity of the right end portion of the outer cylinder member 6 a and the bracket 18.

  The bracket 18 at the top of the inverted chevron truss structure composed of the length-adjustable pulling material 6, the fixed-length diagonal material 11, and the adjustable-length diagonal material 7 is adjustable in length. It is supported from below by a diagonal material 7. The lower end portion of the adjustable slant member 7 that supports the length-adjustable pulling member 6 from below through the inverted angle truss structure is formed between the lower end portion of the web 1a of the main girder 1 and the lower flange 1c. It is attached to the mounting bracket 13 provided at the corner so that the mounting angle can be freely adjusted.

  FIG. 4 is a partially enlarged view of the support construction proposed in Patent Document 1 shown in FIG. 3, and adopts a receiving metal system as a fixing structure.

  The metal fitting 21 is fixed to the side surface near the upper end of the web 1a of the steel main girder 1 with a mounting bolt 22 and a nut 27 in the horizontal direction.

  The bracket 21 has a base plate 21b projecting from the lower front surface of the mounting substrate 21a, and side plates 21c projecting from both the left and right sides above the base plate 21b. Bolts are inserted into the mounting substrate 21a. A plurality of holes 29 are provided at intervals in the vertical direction. A fixing nut 23 is fixed on the base plate 21b by welding, and a longitudinally long hole 25 is provided in each of the two side plates 21c. Further, a lateral bolt insertion hole 30 through which a lateral mounting bolt 22 is inserted is formed in the vicinity of the upper end portion of the web 1 a of the main girder 1.

  When attaching the metal fitting 21, the mounting bolt 21 is attached to one of the bolt insertion holes 29 formed in the mounting substrate 21 a and the bolt insertion hole 30 formed in the vicinity of the upper end of the web 1 a of the main girder 1. By tightening with a nut 27 through 22, the catch 21 is attached and fixed at a required position near the upper end of the web 1 a of the main girder 1.

  In this way, the left end portion of the outer cylinder member 6a of the large pulling member 6 is inserted between the two side plates 21c of the receiving metal fitting 21 attached to the side surface in the vicinity of the upper end portion of the web 1a of the main girder 1. A through hole (not shown) is formed at the left end of both side surfaces of the outer cylinder member 6 a of the large pulling member 6, the vertically long hole 25 provided in both the side plates 21 c of the receiving metal member 21, and the large pulling member 6. After inserting a through bolt 26 through a through hole (not shown) provided on the left end of both side surfaces of the outer cylinder member 6a, the outer cylinder member 6a is prevented from coming off with a nut (not shown). The lateral movement of the left end portion of the cylindrical member 6a is restrained.

  Then, a push-up bolt 24 is screwed into a fixing nut 23 fixed on the base plate 21 b of the receiving metal 21 from below, and the outer cylinder member 6 a of the large pulling member 6 is held at the tip of the push-up bolt 24. Supports the lower surface of the left end. And the height level of the left end part of the outer cylinder member 6a of the large pulling member 6 can be adjusted by moving the push-up bolt 24 up and down in this state.

  Here, a sheet material 31 such as neoprene rubber is attached to the back surface of the mounting substrate 21a that comes into contact with the web 1a of the main beam 1 at the time of mounting the receiving bracket 21 for the purpose of protecting the painted surface of the main beam 1. Has been. Further, a backing plate 32 is attached to the lower surface of the outer end portion of the outer cylinder member 6a against which the upper end portion of the push-up bolt 24 hits.

  Further, on the upper surface of the left end portion of the outer cylinder member 6a of the large pulling member 6, a tension member (also referred to as a contact bolt) 33 that presses against the lower surface of the upper flange portion 1b of the main girder 1 protrudes and has an upper end portion. The suction cup 34 is attached so as to be attracted to the lower surface of the upper flange portion 1b. This is installed in order to prevent the end of the large pulling material from jumping up due to the work load of the worker 14 or the like being applied to the tip of the large pulling material 6. As a result, since the vertical movement of the end portion of the large pulling material is restricted, it is possible to prevent the end portion of the large pulling material from rattling.

  FIG. 5 is a partially enlarged view of a support work according to another embodiment proposed in Patent Document 1, and adopts a suspension bolt system as a fixing structure instead of the receiving metal system.

  A suspension bolt 10 is suspended from a flange connection piece 12 fixed to the upper surface of the top end of the upper flange 1b of the steel main girder 1 by welding, and this suspension bolt 10 is attached to the left end portion of the outer cylinder member 6a of the large pulling member 6. The left end of the outer cylinder member 6a of the large pulling member 6 is supported by passing through the bolt insertion hole 35 drilled in the vertical direction and screwing the receiving nut 37 to the lower end portion of the suspension bolt 10. .

  In the case of this suspension bolt system, a horizontal force generated outward (rightward in the figure) is generated in the suspension bolt 10 due to the load applied to the projecting portion 3a of the mold, so the left end portion of the outer cylinder member 6a of the large pulling material 6 Is attached to the upper end portion of the web 1a of the main girder 1 via the tension fitting 38, so that the outward (rightward in the drawing) horizontal force applied to the suspension bolt 10 is cancelled. The right end of the tension fitting 38 is bolted to the left end of the outer cylinder member 6a of the large pulling member 6, and the left end of the tension fitting 38 is fixed to the corner of the web 1a of the main girder 1 and the upper flange portion 1b. The mounting plate 39 is bolted.

  Further, on the upper surface of the left end portion of the outer cylinder member 6a of the large pulling member 6, a tension member 33 that presses against the lower surface of the upper flange portion 1b of the main girder 1 is projected, and the upper flange portion 1b is formed on the upper end portion thereof. The suction cup 34 is attached so as to be attracted to the lower surface of the. This is installed in order to prevent the end of the large pulling material from jumping up due to the work load of the worker 14 or the like being applied to the tip of the large pulling material 6. As a result, since the vertical movement of the end portion of the large pulling material is restricted, it is possible to prevent the end portion of the large pulling material from rattling.

Japanese Patent Laid-Open No. 2004-60312

  However, all of the supporting works shown in FIGS. 1, 2 and 5 are suspension bolts 10 in which one end portion of the main pulling material 6 on the main beam side is attached to the upper flange portion 1b of the steel main beam. Is suspended by. However, an outward horizontal force is generated in the suspension bolt 10 by a load applied to the projecting portion 3a of the mold. In this state, since a large moment may be generated and the suspension bolt 10 may be bent, the chain 8 is attached to the upper end portion of the web 1a of the main girder 1 in the support work shown in FIGS. In order to cancel the outward horizontal force generated by the load applied to the projecting portion 3a of the frame, the diagonal member 7 whose length is adjustable is pulled. In the support shown in FIG. 5, the left end portion of the outer cylinder member 6 a of the large pulling member 6 is attached to the upper end portion of the web 1 a of the main girder 1 via the tension fitting 38, so that the suspension bolt 10 is attached. This outward horizontal force is canceled out.

  Next, in the support shown in FIGS. 3 and 4, the web 1 a of the main girder 1 made of steel is provided with one end portion (left end portion in the figure) of the main pulling member 6 on the main girder side via the support fitting 21. In the vicinity of the upper end of each of these, a fixing bolt 22 and a nut in the horizontal direction are fixed. An outward (rightward in the figure) horizontal force is generated by the load applied to the overhanging portion 3a of the mold, but since only a tensile force is applied in the length direction of the lateral mounting bolt 22, the mounting bolt 22 There is no risk of bending. Further, since a downward vertical force is generated by the load applied to the projecting portion 3a of the formwork and only the shearing force is applied to the lateral mounting bolt 22, there is no possibility that the mounting bolt 22 is bent.

  However, when the work load of the worker 14 or the like is applied to the tip of the large pulling material 6, the end of the large pulling material jumps up, and as a result, the end of the large pulling material 6 becomes rattled. In order to prevent this, on the upper surface of the left end portion of the outer cylinder member 6a of the large pulling member 6, a tension member 33 is provided so as to press against the lower surface of the upper flange portion 1b of the main girder 1, and at the upper end portion thereof. By attaching a suction cup 34 having a shape that attracts the lower surface of the upper flange portion 1b, the vertical movement of the end portion of the large pulling material 6 is restricted.

  The jumping of the end portion of the large pulling material 6 occurs also in the support shown in FIG. 5, and as a result, the end portion of the large pulling material becomes loose. In order to prevent this, on the upper surface of the left end portion of the outer cylinder member 6a of the large pulling member 6, a tension member 33 is provided so as to press against the lower surface of the upper flange portion 1b of the main girder 1, and at the upper end portion thereof. By attaching a suction cup 34 shaped so as to be attracted to the lower surface of the upper flange portion 1b, the vertical movement of the end portion of the large pulling material is constrained.

  As described above, when the suspension bolt according to the conventional example adopts the suspension bolt method in order to hold one end portion of the large pulling material, it is applied to the projecting portion of the formwork in order to prevent the suspension bolt from being bent. In order to counter the outward horizontal force generated by the load, it is necessary to provide a troublesome hanging chain or to provide a tension fitting.

  And when the support according to the conventional example adopts a receiving bracket method to hold one end of the large pulling material, the receiving bracket is fixed by a lateral mounting bolt and nut, so that it faces outward. Although there is no possibility that the mounting bolt bends due to the horizontal force, the end of the large pulling material jumps up, and as a result, the end of the large pulling material becomes loose. In order to prevent this, it is necessary to project a tension member.

  Furthermore, in the support work according to the conventional example, the worker works on the scaffolding plate installed on the upper surface of the other end of the large pulling material, but the slope of the cross section of the road where the bridge is hung is steep. In some cases, the angle of inclination of the large pulling material becomes steeper accordingly. Therefore, since the tread angle of the scaffolding plate on which the worker works is steep, there is a problem in terms of worker safety in addition to the problem that it is difficult to work on the scaffolding plate.

  The present invention has been made in order to solve such problems, and a first object of the present invention is to provide a support work that requires neither a suspension chain nor a brace. Furthermore, it is a second object to provide a support that can hold the tread surface of the scaffolding plate on which the worker works as required.

  The present inventor has made various studies on support works that require neither a suspension chain nor a bracing material. In addition, various studies were also conducted on support structures that can hold the treads of the scaffolding plates on which workers work. As a result, the following findings (a) to (j) were obtained.

  (a) When the overhanging part of the concrete floor slab formwork that extends from the upper flange part of the main girder made of steel is enlarged, it is necessary to arrange it horizontally below the overhanging part of this formwork. The pulling material is also enlarged and the weight is increased. However, even if the size of the overdrawing material is increased, as a support for supporting the overhanging portion of the concrete floor slab formwork, a large overhanging material disposed laterally below the overhanging portion of the formwork and this It is composed of diagonal materials that can be adjusted in length to support the large pulling material from diagonally below. One end of the large pulling material is fixed to the main girder via a receiving bracket, and this large pulling material is supported diagonally from below. You can keep the basic concept.

  The basic concept of this support work is not only the support work for supporting the overhanging part of the concrete floor slab form, which is overhanging the upper flange part of the steel main girder, but also the main work made of concrete. The present invention can also be applied to a supporting work for supporting a projecting portion of a concrete floor slab form that projects from an upper flange portion of a girder.

  (b) The diagonal member capable of adjusting the length supporting the large pulling material obliquely from below is connected to the other end portion or the non-end portion of the large pulling material at an attachment angle, and the lower end of the diagonal material. It is preferable that the portion is attached to the web portion of the main girder or the lower flange portion so that the mounting angle can be freely adjusted. There is no particular limitation on the method of changing the length of the diagonal member. For example, the diagonal member is composed of a hollow outer cylindrical member and an inner cylindrical member slidably inserted into the outer cylindrical member. Can do. Alternatively, the length may be variable by incorporating a screw jack or a hydraulic jack in the middle of the diagonal member. Furthermore, the length of the diagonal member may be variable by combining these. The large pulling material may be a fixed length or a variable length. In the case where the length of the large pulling material is variable, as shown in FIG. 3, the large pulling material may be supported obliquely from below by an oblique material whose length is adjustable via an inverted mountain truss structure.

  (c) Considering that the bolt is weak against bending stress but strong against shear stress, when attaching one end of the large pulling material to the main girder, the end of the large pulling material will be separated from the main girder. Suspension bolts should not be used, but metal fittings that can be fixed by bolts in close contact with the main girder should be used.

  At this time, the metal fitting to be attached to the main girder is to attach the metal fitting to which the end portion of the large pulling material is in close contact with the side of the upper end of the main girder web, and the lower surface of the upper flange of the main girder. There are two possible cases of close contact and fixation.

  When fixing the bracket to the side of the upper end of the main girder's web, an outward horizontal force is generated by the load applied to the overhanging part of the formwork, but because the bolt is attached in the lateral direction, Since only a tensile force is applied in the length direction of the mounting bolt, there is no possibility that the mounting bolt bends. Further, since a downward vertical force is generated by the load applied to the projecting portion 3a of the formwork and only a shearing force is applied to the lateral mounting bolt, there is no possibility that the mounting bolt is bent.

  If the main girder is fixed in close contact with the lower surface of the upper flange, even if an outward horizontal force is generated by the load applied to the overhanging part of the formwork, the bolt can be attached in the vertical direction. Since only shearing force is applied to the mounting bolt, there is no possibility that the mounting bolt bends. Further, a downward vertical force is generated by a load applied to the projecting portion 3a of the mold, but since only a tensile force is applied in the length direction of the mounting bolt, there is no possibility that the mounting bolt is bent.

  (d) As described above, the end portion of the large pulling material can be attached to the receiving metal fitting in close contact with the main beam. And since the attachment bolt for attaching a metal fitting to a main girder closely_contact | adheres with a main girder, even if it uses it in any of a horizontal direction and a vertical direction, there is no possibility of bending.

  When the bracket is attached to the main girder with a bolt, a nut may be tightened to a bolt that is pre-installed or embedded in the main girder, whether it is used in the horizontal or vertical direction, A bolt may be screwed into a nut that is pre-installed or embedded in the beam and tightened. When the main girder is made of steel, the bolt insertion hole is drilled in the lateral direction at the upper end of the main girder web or vertically in the upper flange of the main girder. When the main girder is made of concrete, the anchor bolt or the anchor nut is embedded in the upper end portion of the main girder web in the lateral direction or in the upper flange of the main girder in the upward direction.

  However, in consideration of the fact that this support is dismantled and removed after placing the concrete on the overhang of the formwork, a method of tightening bolts on nuts attached to or embedded in the main girder is adopted. Is preferred. In this case, the nut attached to or embedded in the main girder remains in the main girder, but since the bolts screwed into this nut can be removed, there are no protrusions from the main girder after the support work is removed. It is because it is preferable from a surface. In addition, it is preferable to use an insert nut as a nut attached to or embedded in a concrete main beam.

  (e) Next, regarding the prevention of the occurrence of the jumping of the end portion of the large pulling material, a fixing structure by a receiving metal fitting method that is fixed in close contact with the side surface of the upper end portion of the main girder web is shown in FIGS. ing. This is because a through bolt 26 is inserted through a vertically long hole 25 provided in both of the side plates 21c of the metal fitting 21 and a through hole (not shown) provided in the left end portion of the large pulling member 6, and then a nut (see FIG. (Not shown) to prevent the left end portion of the pulling material 6 from moving laterally. However, since the vertical movement of the left end portion of the large pulling material 6 is not constrained, it has been found that the end portion of the large pulling material jumps up.

  That is, in the fixing structure by the receiving metal method shown in FIGS. 3 and 4, the side plate 21 c of the receiving metal 21 is provided with the vertically long hole 25, so the lateral movement of the left end portion of the large pulling material 6 is The reason is that the vertical movement is not restricted.

  Here, in the fixing structure by the receiving metal fitting method, the present inventors can not only move the left end portion of the large pulling member 6 in the lateral direction by inclining the angle of the vertically long hole provided in the side plate. The inventors have found that it is possible to restrain the movement in the vertical direction, and it has been found that it is possible to prevent the end of the pulling material from jumping up. Specifically, in the fixing structure by the receiving bracket method in which the upper end portion of the main girder web is fixed in close contact with the side plate 21c of the receiving bracket 21, the upper end is the main girder instead of providing the vertically long hole 25. By providing a slanted vertical hole inclined at an inclination angle θ in the web center direction, not only the lateral movement of the left end portion of the large pulling material 6 can be restricted, but also the vertical movement can be restricted. I found.

  (f) The inventors of the present invention, in the fixing structure by the receiving bracket method that is fixed in close contact with the side surface of the upper end portion of the main girder web, has an obliquely long elongated hole whose upper end is inclined by an inclination angle θ in the main girder direction. The idea of providing the same is applied to a fixing structure using a receiving bracket that is fixed in close contact with the lower surface of the upper flange of the main girder. Both the lateral movement and the vertical movement of the left end of the large pulling material 6 It has been found that the pulling force applied in the longitudinal direction of the bolt attached in the longitudinal direction can be reduced in addition to preventing the end of the large pulling material from jumping up.

  In addition, in this fixing structure using the bracket, a pin such as an L pin is used instead of inserting a through bolt between the obliquely long hole and the through hole provided at the left end of the large pulling material, and fixing with a nut. It may be used to restrain the horizontal movement and the vertical movement of the left end portion of the large pulling material.

  (g) First of all, regarding the occurrence of the jumping of the end of the large pulling material in the fixing structure using the receiving bracket method that is fixed in close contact with the lower surface of the upper flange of the main girder, a vertically long hole (θ = 0 °) ) And a case where a diagonally long hole (θ = 30 °) is provided is examined. Here, L pins were used instead of through bolts.

  FIG. 6 shows a situation in which the end portion of the large pulling material jumps up when a vertically long hole (θ = 0 °) is provided in the side plate of the receiving metal fitting. Before the concrete is placed, the work load of the operator 14 and the like acts on the tip of the large pulling material, so that it jumps up (upward) with the intersection of the large pulling material and the diagonal material supporting the large pulling material from below as a fulcrum. A force F2V is generated. On the other hand, the force resisting jumping is F2H × (friction coefficient). As shown in the figure, since F2V> F2H × (friction coefficient), it can be seen that the jump occurs.

  FIG. 7 shows a situation in which the end portion of the large pulling material is bounced up when a vertically long hole (θ = 30 °) is provided in the side plate of the receiving metal fitting. Before the concrete is placed, the work load of the operator 14 and the like acts on the tip of the large pulling material, so that it jumps up (upward) with the intersection of the large pulling material and the diagonal material supporting the large pulling material from below as a fulcrum. A force F2V is generated. On the other hand, the force resisting jumping is F2H × (friction coefficient). As shown in the figure, since F2V <F2H × (friction coefficient), it can be seen that no jumping occurs.

  (h) In this way, a fixing structure using a receiving bracket method is adopted, and instead of the vertically long hole provided in the side plate, a slanted vertically long hole whose upper end is inclined by an angle θ in the web center direction of the main girder is provided. Therefore, if F2V <F2H × (friction coefficient), it is possible to prevent the end portion of the large pulling material from jumping up, and the left end portion of the large pulling material 6 is not rattled. It was.

  And, as a result of various investigations on the condition of F2V <F2H × (friction coefficient), the present inventors are able to adjust the length of supporting the node of the pin inserted through the obliquely elongated hole and the large pulling material from obliquely below. Although there is some variation depending on the vertical distance H between the lower end of the diagonal member, when the vertical distance H = 1800 mm, which is generally used as a support work, the upper end is inclined toward the web center of the main girder. It has been found that it is preferable to make the inclination angle of the oblique long hole larger than θ = 25 °. Further, when the inclination angle exceeds θ = 45 °, the elongated holes become sideways and the height level adjusting function of the pulling material 6 which is the original purpose of the elongated holes is impaired. It turned out that it is preferable to set it as = 25-45 degrees.

  (i) Next, it is explained that the pulling force applied in the longitudinal direction of the bolt attached in the vertical direction can be reduced in the fixing structure by the receiving bracket method that is fixed to the lower surface of the upper flange of the main girder. To do. Here, a concrete main girder will be described as an example, but it goes without saying that it can also be applied to a steel main girder.

  FIG. 8 shows the horizontal load and the vertical load applied to the receiving bracket in the support structure of the fixing structure using the receiving bracket method in which the concrete main girder is fixed in close contact with the lower surface of the upper flange.

  Here, P is a load (kN) applied to the upper end of the diagonal member, L is a position (cm) where the load P applied to the upper end of the diagonal member is applied, and H is a node of the pin inserted through the oblique vertical hole and the diagonal member. Is the vertical distance (cm) between

At this time, the moment M acting on the upper end of the diagonal is M = P × L (kN · cm)
And the load acting on the node of the pin inserted through the slanted vertical hole of the metal fitting is divided into a horizontal load PH and a vertical load PV, respectively,
PH = M / H (kN)
PV = P (kN)
It becomes.

  FIG. 9 shows a case in which the position of the anchor bolt and the position where the vertical load PV acts is eccentric by 75 mm as a receiving bracket system in which the receiving bracket is fixed in close contact with the lower surface of the upper flange of the concrete main girder. The horizontal load PH and the vertical load PV acting on the node of the pin inserted through the diagonally long hole of the metal fitting are shown.

  As described above, when the position of the anchor bolt and the position where the vertical load PV acts is eccentric by 75 mm, the moment acting by the horizontal load PH and the moment acting by the vertical load PV cancel each other. The load acting on the anchor bolt is reduced.

  In FIG. 10, (a) represents the horizontal load PH, and (b) represents the vertical load PH, each representing the direction of rotation with the anchor bolt as a base point.

  In (a), it rotates counterclockwise from the anchor bolt as the base point, and in (b), it rotates clockwise from the anchor bolt as the base point, so both moments cancel each other and the load acting on the anchor bolt It turns out that becomes small.

  Next, the load acting on the anchor bolt will be verified.

When the horizontal load PH is 10 kN, the vertical load PV is 2 kN, and the vertical distance h from the anchor bolt to the pin position is 10 cm,
The moment M1 acting counterclockwise is generated by the horizontal load PH, and its value is as follows.

M1 = PH × h = 10 kN × 10 cm = 100 kN · cm
The moment M2 acting clockwise is generated by the load PV in the vertical direction, and its value is as follows.

M2 = PV × 7.5 cm = 2 kN × 7.5 cm = 15 kN · cm
Since M1> M2, a counterclockwise moment is generated. However, since the counterclockwise moment is canceled, the value of the counterclockwise moment M is as follows.

M = M1-M2 = 100-15 = 85 kN · cm
The pulling force P1 acting on the anchor bolt by the moment M after the cancellation is as follows.

P1 = M / 14.5 = 85 / 14.5 = 5.86 kN
And since the load PV (= P (kN)) of the perpendicular direction is originally applied to the anchor bolt, the total pulling force ΣP acting on the anchor bolt is as follows.

ΣP = PV + P1 = 2 + 5.86 = 7.86 kN
For comparison, as a receiving bracket system in which the receiving bracket is fixed in close contact with the lower surface of the upper flange of the concrete main girder, the position of the anchor bolt and the position where the vertical load PV acts is not eccentric. Validate.

  FIG. 11 shows that the position of the anchor bolt and the position where the vertical load PV acts are not eccentric, that is, the position of the anchor bolt and the position where the vertical load PV acts are on the same vertical line. ing.

  The load acting on the anchor bolt in this case will be verified.

Similarly to FIG. 10, when the horizontal load PH is 10 kN, the vertical load PV is 2 kN, and the vertical distance h from the anchor bolt to the pin position is 10 cm,
The moment M1 acting counterclockwise is generated by the horizontal load PH, and its value is as follows.

M1 = PH × h = 10 kN × 10 cm = 100 kN · cm
However, as described below, the moment M2 acting clockwise by the load PV in the vertical direction is not generated. That is,
M2 = PV × 0 cm = 2 kN × 0 cm = 0 kN · cm
Since M2 = 0 kN · cm, the value of the counterclockwise moment M is not canceled out, and is as follows.

M = M1-M2 = 100-0 = 100 kN · cm
The pull-out force P1 acting on the anchor bolt by this counterclockwise moment M is as follows.

P1 = M / 14.5 = 100 / 14.5 = 6.9 kN
And since the load PV (= P (kN)) of the perpendicular direction is originally applied to the anchor bolt, the total pulling force ΣP acting on the anchor bolt is as follows.

ΣP = PV + P1 = 2 + 6.9 = 8.9 kN
Thus, when the position of the anchor bolt and the position at which the vertical load PV acts are eccentric, the pulling force acting on the anchor bolt can be reduced. However, the distance from the anchor bolt to the main girder web center needs to be smaller than the distance from the pin to the main girder web center. When the distance from the anchor bolt to the web center of the main girder is larger than the distance from the pin to the main girder web center, the pulling force acting on the anchor bolt is conversely increased.

  (j) Furthermore, when the cross-sectional inclination of the road on which the bridge is hung is steep, the inclination angle of the large pulling material also becomes steep, and the tread angle of the scaffolding plate on which the worker works is also steep. This problem can be solved if the footsteps of the scaffolding plate can be kept substantially horizontal regardless of the angle of inclination of the cross section of the road or the like on which the bridge is hung. Therefore, if necessary, the scaffolding material may be connected to the end portion of the large pulling material so that the attachment angle can be adjusted, and the scaffolding plate may be installed on the scaffolding material.

  As a method of connecting the scaffolding member so that the mounting angle can be adjusted, for example, a plurality of angle adjusting holes are provided, and the scaffolding member and / or the pulling member can be freely rotated with respect to the scaffolding member and / or the pulling member. A scaffolding material may be connected to the tip, and one of the angle adjustment holes may be selected and pinned so that the tread surface of the scaffolding plate installed thereon is substantially horizontal.

  The support work according to the present invention has been completed based on these findings, and the gist thereof is as described in the following (1) to (8).

  (1) A large pulling material placed under the overhanging part of the formwork to support the concrete formwork of the floor slab overhanging part provided overhanging from the upper flange part of the main girder and this large pulling material obliquely This is a support made of diagonal material that can be adjusted from the bottom, and has a slanted vertical hole whose upper end is inclined toward the web center of the main girder, and is in close contact with the lower surface of the upper flange of the main girder A bolt or a pin is inserted in the lateral direction between the slanted vertical hole and the through hole provided at one end of the large pulling material through the receiving metal fitting fixed in this manner, and the large pulling material is received. A support that is attached to a metal fitting.

  (2) The support according to the above (1), wherein the slanted vertical hole has an inclination angle θ of 25 to 45 °.

  (3) The above-mentioned (1), wherein the metal fitting is fixed in close contact with the lower surface of the upper flange portion of the main girder by tightening a nut to a bolt attached to or embedded in the main girder. ) Or support work of (2).

  (4) The above-mentioned (3), wherein the distance from the bolt attached to or embedded in the main girder to the web center of the main girder is smaller than the distance from the through bolt or pin to the main girder web center Support work.

  (5) The above-mentioned (1), wherein the metal fitting is fixed in close contact with the lower surface of the upper flange portion of the main girder by tightening a bolt to a nut attached to or embedded in the main girder. ) Or support work of (2).

  (6) The above (5), wherein the distance from the nut attached to or embedded in the main girder to the web center of the main girder is smaller than the distance from the through bolt or pin to the main girder web center Support work.

  (7) The support bracket includes a fixing nut fixed to a lower portion thereof and a push-up bolt that can be screwed to the fixing nut. Engineering.

  (8) The support according to any one of (1) to (7) above, wherein a scaffolding material is connected to the other end of the large pulling material so that the mounting angle can be adjusted.

  The support according to the present invention does not require both a troublesome suspension chain and a tension member, and the end portion of the large pulling material is brought into close contact with the lower surface of the upper flange portion of the main girder and is bolted. Since a fixing bracket that can be fixed is used, it can counter the outward horizontal force generated by the load applied to the overhanging portion of the formwork, and the bracket has an obliquely elongated hole whose upper end is inclined toward the center of the web of the main girder. Thus, in addition to preventing the end portion of the large pulling material from jumping up, it is possible to reduce the pulling force applied in the longitudinal direction of the bolt attached in the vertical direction.

  In addition, if necessary, the scaffolding material can be connected to the end of the large pulling material so that the mounting angle can be adjusted. By installing the scaffolding board on the top, the tread surface of the scaffolding board on which the worker works can be kept substantially horizontal, and the safety of the worker can be enhanced.

  The support according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited to a following example.

  FIG. 12 is an example (side view) of the support according to the present invention installed outside the concrete main girder, and FIG. 13 is the end portion of the main girder side of the large pulling material shown in FIG. It is a partially enlarged view of the vicinity.

  An insert nut 52 is vertically embedded in the lower surface of the upper flange 1b of the main girder 1 made of concrete, and the upper flange of the main girder 1 is screwed to the insert nut 52 in the vertical direction. The receiving metal fitting 21 is fixed in close contact with the lower surface of the portion 1b. On both side surfaces of the metal fitting 21, there are provided oblique vertical holes 53 whose upper ends are inclined toward the web center of the main girder. In addition, the inclination angle θ of the slanted vertical hole 53 is 30 °.

  On the other hand, under the projecting portion 3 a of the formwork of the concrete floor slab 2, a large pulling material 6 is disposed via a joist material 9. Connection plates 41 are welded to both side surfaces of the end portion of the large pulling material 6, respectively. Each of these connection plates 41 is provided with a through hole (not shown), and each of these connection plates 41 is accommodated in the interior of the receiving bracket 21 and then obliquely elongated holes provided in the receiving bracket. By inserting a single L pin 54 into the through hole formed in the connection plate 41 and the connection plate 41, the end portion of the large pulling material 6 is held by the receiving bracket 21 so as not to be lifted.

  Further, a height level adjusting bracket 55 is welded to the lower portion of the receiving bracket 21, and a fixing nut 23 fixed to the lower portion of the height level adjusting bracket 55 is screwed to the fixing nut 23 to move up and down. A movable push-up bolt 24 is provided. On the other hand, a pedestal fitting 56 is welded laterally to the end of the large pulling material 6, and the height of the end of the large pulling material 6 is increased by inserting the pedestal fitting 56 into the upper surface of the push-up bolt 24. You can adjust the level adjustment.

  And the attachment metal fitting 13 is provided in the non-end part of the large pulling material 6, and the upper end of the diagonal material 7 which can adjust length is attached to the attachment angle freely here. This length-adjustable diagonal member 7 is composed of a hollow outer cylinder member 7a and an inner cylinder member 7b that is slidably inserted into the outer cylinder member, and is drilled in both members 7a and 7b. The length can be adjusted by selecting one from each hole, inserting a pin (not shown) therethrough, and fixing the positions of both members 7a and 7b. Further, the diagonal member 7 incorporates a screw jack 36 in the middle of the diagonal member 7, and the length can be adjusted by operating the screw jack 36.

  Further, a mounting bracket 13 having an adjustable mounting angle is connected to the lower end of the diagonal member 7 whose length can be adjusted. On the other hand, an insert nut 52 is obliquely embedded in the upper surface of the lower flange 1c of the main girder 1, and the mounting bracket 13 provided at the lower end of the diagonal member 7 whose length can be adjusted is fixed with a mounting bolt 22 here. By doing so, the large pulling material 6 is supported from below.

  Further, the scaffold member 20 is connected to the other end portion of the large pull member 6 via a scaffold member mounting bracket 58. On the scaffolding material 20, a scaffolding plate 15 for the worker 14 to work is installed. This scaffolding material mounting bracket 58 attaches the scaffolding material 20 to the other end portion of the large pulling material 6. By making the angle adjustable, the tread surface of the scaffold plate 15 installed on the scaffold member 20 can be kept substantially horizontal. Further, a handrail column 16 and a handrail material 17 are attached to the other end portion of the large pulling material 6 in order to prevent the worker 14 from falling.

  FIG. 14 shows an example of a large pulling material according to the present invention. (a) is a front view, (b) is a bottom view, (c) is a left side view, and (d) is a cross-sectional view taken along line AA.

  The large pulling material 6 is a tube having a rectangular cross section, and connection plates 41 are welded to both side surfaces of one end portion thereof. Through holes 42 are formed in the connection plates 41 welded to both side surfaces of one end of the large pulling material 6. Both of the two connection plates 41 are accommodated in the receiving bracket 21, and then the two oblique long holes 53 provided in the receiving bracket 21 and the through holes 42 formed in each of the two connection plates 41. In addition, by inserting one L pin (not shown), the large pulling material 6 is held by the receiving metal fitting 21 so that one end of the large pulling material 6 does not float up.

  A base metal fitting 56 is welded to one end of the large pulling material 6 in the lateral direction. Note that the height level of one end of the large pulling material 6 is adjusted by inserting the base metal fitting 56 into the upper surface of the push-up bolt 24 of the height level adjusting metal fitting 55.

  Further, a mounting bracket 13 is provided at a non-end portion of the large pulling material 6, and an upper end portion of the diagonal member 7 is attached to the mounting member 13 at any angle.

  Further, three sets of L pin through holes 61 and one set of bolt through holes 62 are formed in the other end portion (right end portion in the drawing) of the large pulling material 6 in order from the left. In addition, the other end part of this large pulling material 6 is attached with a scaffolding material mounting bracket 58 to which the scaffolding material 20 is joined by welding (see FIG. 12). Here, the bolt is passed through the bolt through hole 62 formed in the other end portion of the large pulling member 6 and tightened with a nut to connect the scaffolding plate mounting bracket 58 to the other end portion of the large pulling member 6, By selecting one set of L pin through holes out of the three sets of L pin through holes 61, the scaffolding material 20 can be kept substantially horizontal, so that the tread surface of the scaffold plate 15 installed thereon is substantially omitted. Can be kept level. Therefore, when the cross-sectional inclination of the road where the bridge is hung is steep, the scaffolding material is connected to the end of the large pulling material so that the mounting angle can be adjusted, and the scaffolding plate is installed on this scaffolding material. It is possible to prevent the worker from falling and to ensure safety.

  With reference to FIG. 15, a procedure for holding one end portion of the large pulling material 6 on the lower surface of the upper flange portion of the main girder made of concrete using the metal fitting according to the present invention will be described. (a) is a top view, (b) is a front view, and (c) is a left side view.

  The receiving bracket 21 has a U-shaped cross section, and oblique long holes 53 of θ = 30 ° are provided on both side surfaces. An upper reinforcing washer 60 is joined to the upper surface of the receiving metal 21 by welding W, and a bolt insertion hole 35 is formed in the vertical direction so as to penetrate the upper reinforcing washer 60 and the upper surface of the receiving metal 21. After aligning the bolt insertion hole 35 of the bracket 21 with the insert nut embedded in the lower surface of the upper flange portion of the concrete main girder, the mounting bolt 22 is screwed to fix the bracket 21 to the main girder. Fixed.

  In addition, after accommodating the connection plates 41 welded to the both side surfaces of the end portion of the large pulling member 6 in the interior of the receiving metal member 21, the diagonally long holes 53 provided on both side surfaces of the receiving metal member 21 and the large pulling material 6 By inserting a single L pin 54 through a through hole (not shown) drilled in each of the connection plates 41 welded to both side surfaces of the end portion, the end portion of the large pulling material 6 does not float up. I was able to.

  Further, a height level adjusting fitting 55 having a U-shaped cross section is joined to the lower portion of the receiving fitting 21 by welding W. Then, a lower reinforcing washer 59 is joined to the outside of the lower portion of the height level adjusting fitting 55 by welding W, and the bolt insertion hole 35 is vertically formed so as to penetrate the lower reinforcing washer 59 and the lower portion of the height level adjusting fitting 55. Has been worn. A fixing nut 23 is fixed to the inside of the lower portion of the height level adjusting fitting 55, and a push-up bolt 24 that is screwed into the fixing nut 23 and is movable up and down is provided.

  In addition, by inserting the base metal fitting 56 welded in the lateral direction to the end of the large pulling material 6 on the upper surface of the push-up bolt 24 and moving the push-up bolt 24 up and down, the height level of the end of the large pulling material 6 is increased. Adjustment can be adjusted.

  In this way, the end of the large pulling material is attached to the receiving metal fitting that can be fixed to the lower surface of the upper flange part of the main girder made of concrete and secured with bolts, which is caused by the load on the overhanging part of the formwork In addition to being able to counter the outward horizontal force, the catch has a slanted vertical hole whose upper end is inclined toward the web center of the main girder. The pulling force applied in the length direction of the bolt attached in the vertical direction can be reduced.

  FIG. 16 is another example (side view) of the support according to the present invention installed outside the steel main beam, and FIG. 17 is a diagram of the main beam side of the large pulling material shown in FIG. It is a partial enlarged view of the edge vicinity.

  The catch 21 is fixed to the lower surface of the upper flange 1b of the steel main girder 1 by screwing a mounting bolt 22 in a vertical direction to an insert nut 52 disposed on the upper surface of the flange. . On both side surfaces of the metal fitting 21, there are provided oblique vertical holes 53 whose upper ends are inclined toward the web center of the main girder. In addition, the inclination angle θ of the slanted vertical hole 53 is 30 °.

  On the other hand, under the projecting portion 3 a of the formwork of the concrete floor slab 2, a large pulling material 6 is disposed via a joist material 9. Connection plates 41 are welded to both side surfaces of the end portion of the large pulling material 6, respectively. Each of these connection plates 41 is provided with a through hole (not shown), and each of these connection plates 41 is accommodated in the interior of the receiving bracket 21 and then obliquely elongated holes provided in the receiving bracket. By inserting a single L pin 54 through the through hole formed in the connection plate 41 and the connection plate 41, the end of the large pulling material 6 is held by the receiving bracket 21 so as not to be lifted.

  Further, a height level adjusting bracket 55 is welded to the lower portion of the receiving bracket 21, and a fixing nut 23 fixed to the lower portion of the height level adjusting bracket 55 is screwed to the fixing nut 23 to move up and down. A movable push-up bolt 24 is provided. On the other hand, a pedestal fitting 56 is welded laterally to the end of the large pulling material 6, and the height of the end of the large pulling material 6 is increased by inserting the pedestal fitting 56 into the upper surface of the push-up bolt 24. You can adjust the level adjustment.

  And the attachment metal fitting 13 is provided in the non-end part of the large pulling material 6, and the upper end of the diagonal material 7 which can adjust length is attached to the attachment angle freely here. This length-adjustable diagonal member 7 is composed of a hollow outer cylinder member 7a and an inner cylinder member 7b that is slidably inserted into the outer cylinder member, and is drilled in both members 7a and 7b. The length can be adjusted by selecting one from each hole, inserting a pin (not shown) therethrough, and fixing the positions of both members 7a and 7b. Further, the diagonal member 7 incorporates a screw jack 36 in the middle of the diagonal member 7, and the length can be adjusted by operating the screw jack 36.

  Further, a mounting bracket 13 having an adjustable mounting angle is connected to the lower end of the diagonal member 7 whose length can be adjusted. Then, the large pulling member 6 is supported from below by fixing the mounting bracket 13 to the corners of the lower end portion of the web 1a of the main girder 1 and the lower flange 1c with mounting bolts 22 and nuts 27 so that the mounting angle can be freely adjusted. ing.

  Further, the scaffold member 20 is connected to the other end portion of the large pull member 6 via a scaffold member mounting bracket 58. On the scaffolding material 20, a scaffolding plate 15 for the worker 14 to work is installed. This scaffolding material mounting bracket 58 attaches the scaffolding material 20 to the other end portion of the large pulling material 6. By making the angle adjustable, the tread surface of the scaffold plate 15 installed on the scaffold member 20 can be kept substantially horizontal. Further, a handrail column 16 and a handrail material 17 are attached to the other end portion of the large pulling material 6 in order to prevent the worker 14 from falling.

  This large pulling material 6 is the same as that used in Example 1. That is, each of the tubes has a rectangular cross section, and the connection plates 41 are welded to both side surfaces of one end thereof. Through holes 42 are formed in the connection plates 41 welded to both side surfaces of one end of the large pulling material 6. Both of the two connection plates 41 are accommodated in the receiving bracket 21, and then the two oblique long holes 53 provided in the receiving bracket 21 and the through holes 42 formed in each of the two connection plates 41. In addition, by inserting one L pin (not shown), the large pulling material 6 is held by the receiving metal fitting 21 so that one end of the large pulling material 6 does not float up. Further, a pedestal fitting 56 is welded to one end of the large pulling material 6 in the lateral direction, and the large pulling material is inserted by inserting the pedestal fitting 56 into the upper surface of the push-up bolt 24 of the height level adjustment fitting 55. At the point where the height level of one end portion of 6 is adjusted, and at the non-end portion of the large pulling material 6, a mounting bracket 13 is provided, and the upper end portion of the diagonal member 7 can be freely mounted at any angle. The point of attachment is also the same as in the first embodiment.

  Furthermore, three sets of L pin through holes 61 and one set of bolt through holes 62 are formed in the other end portion of the large pulling material 6, and the scaffold material attachment to which the scaffold material 20 is joined by welding. Since the bracket 58 can keep the scaffolding material 20 substantially horizontal, the tread surface of the scaffolding plate 15 installed thereon can be kept substantially horizontal as in the first embodiment.

  In this way, the end of the large pulling material is attached to the receiving metal fitting that is in close contact with the lower surface of the upper flange part of the steel main girder and can be fixed with bolts. In addition to being able to counter the outward horizontal force, the bracket has a slanted vertical hole whose upper end is inclined in the direction of the center of the web of the main girder. By pulling out the position of the anchor bolt and the position where the load in the vertical direction acts, the pulling force applied in the length direction of the bolt attached in the vertical direction can be reduced.

  According to the present invention, since it is possible to provide a support work that eliminates the need for both the suspension chain and the tension member, in addition to being able to easily perform the support work, the bolt attached in the vertical direction can be provided. The pulling force applied in the length direction can be reduced. Moreover, since the tread of the scaffolding plate on which the worker works can be held substantially horizontally as necessary, the safety of the worker can be ensured even when the cross-sectional inclination of the road or the like on which the bridge is hung is steep.

It is sectional drawing which shows an example of the concrete floor slab of the bridge concerning a prior art example. It is an example (side view) of the support work which concerns on the prior art example installed in the outer side of the main girder. It is a side view of the support construction proposed in patent documents 1 installed in the outside of the main girder. FIG. 4 is a partially enlarged view of the support work proposed in Patent Document 1 shown in FIG. 3, and adopts a receiving bracket system as a fixing structure. It is a partial enlarged view of the support work concerning other embodiment proposed in patent documents 1, and it replaces with a bracket method as a fixed structure, and adopts a suspension bolt method. The state of occurrence of jumping of the end of the large pulling material when a vertically long hole (θ = 0 °) is provided in the side plate of the receiving metal is shown. The state of occurrence of the jumping of the end of the large pulling material when a vertically long hole (θ = 30 °) is provided in the side plate of the metal fitting is shown. The horizontal load and the vertical load applied to the receiving metal are shown. When the position of the anchor bolt and the position where the vertical load PV acts is eccentric by 75 mm, the horizontal load PH and the vertical load PV acting on the node of the pin inserted through the diagonally long hole of the receiving metal fitting Is shown. (a) shows the direction of rotation about the load PH in the horizontal direction, and (b) shows the direction of rotation about the load PV in the vertical direction with the anchor bolt as the base point. When the position of the anchor bolt and the position where the vertical load PV acts are not decentered, the horizontal load PH and the vertical load PV acting on the node of the pin inserted through the diagonally long hole of the receiving metal fitting Show. It is an example (side view) of the support work based on this invention installed in the outer side of the main girder made from concrete. FIG. 13 is a partially enlarged view of the vicinity of the end portion on the main girder side of the large pulling material shown in FIG. 12. An example of the large pulling material which concerns on this invention is shown. (a) is a front view, (b) is a bottom view, (c) is a left side view, and (d) is a cross-sectional view taken along line AA. A procedure for holding one end portion of the large pulling material on the lower surface of the upper flange portion of the main girder made of concrete using the metal fitting according to the present invention will be described. (a) is a top view, (b) is a front view, and (c) is a left side view. It is the other example (side view) of the support work based on this invention installed in the outer side of the steel main girders. FIG. 17 is a partially enlarged view of the vicinity of the end portion on the main beam side of the large pulling material shown in FIG. 16.

Explanation of symbols

1 Main girder 1a Main girder web part 1b Main girder upper flange part 1c Main girder lower flange part 2 Concrete floor slab 3 Formwork 3a Formwork overhanging part 4 Horizontal support beam 5 Pipe support 6 Large pulling material 6a Length Adjustable large pulling outer cylinder member 6b Adjustable length pulling inner cylinder member 7 Adjustable length slant 7a Adjustable length slant outer cylinder member 7b Adjustable length slant Inner cylinder member 8 Suspension chain 9 joist material 10 Suspension bolt 11 Fixed length diagonal material 12 Flange connection piece 13 Mounting bracket 14 Worker 15 Scaffold plate 16 Handrail pillar 17 Handrail material 18 Bracket 19 Reinforcement rod 20 Scaffold material 21 Receiving Bracket 21a Mounting board 21b Base plate 21c Side plate 22 Mounting bolt 23 Fixing nut 24 Push-up bolt 25 Vertically long hole 26 Through bolt 27 Nut 29 Mounting board bolt insertion hole 30 Bolt insertion hole 31 Sheet material 32 Baffle plate 33 Strut material 34 Suction cup 35 Bolt insertion hole 36 Screw jack 37 Receiving nut 38 Tension fitting 39 Mounting plate 41 Connection plate 42 Through hole 52 Insert nut 53 Oblique vertical hole 54 L pin 55 Height Level adjustment bracket 56 Base bracket 58 Scaffold mounting bracket 59 Lower reinforcement washer 60 Upper reinforcement washer 61 L pin through hole 62 of scaffold mounting bracket Bolt through hole W of scaffold mounting bracket Welding

Claims (8)

  To support the concrete formwork of the floor slab overhanging part that projects from the upper flange part of the main girder, a large pulling material disposed below the overhanging part of the formwork and the large pulling material are supported from obliquely below This is a support made of diagonal material with adjustable length, and has an oblique vertical hole whose upper end is inclined toward the web center of the main girder, and is in close contact with the lower surface of the upper flange part of the main girder. A bolt or pin is inserted in the lateral direction between the slanted vertical hole and the through hole provided at one end of the large pulling material through the receiving metal fitting, and the large pulling material is attached to the receiving metal fitting. Supporting work characterized by being.   The support structure according to claim 1, wherein the inclined angle of the oblong hole is θ = 25 to 45 °.   The receiving metal fitting is fixed in close contact with the lower surface of the upper flange portion of the main girder by tightening a nut to a bolt attached to or embedded in the main girder. The support work described.   The support according to claim 3, characterized in that the distance from the bolt attached to or embedded in the main girder to the web center of the main girder is smaller than the distance from the through bolt or pin to the main girder web center. Engineering.   The receiving metal fitting is fixed in close contact with the lower surface of the upper flange portion of the main girder by tightening a bolt to a nut attached to or embedded in the main girder. The support work described.   6. Support according to claim 5, characterized in that the distance from the nut attached to or embedded in the main girder to the web center of the main girder is smaller than the distance from the through bolt or pin to the center of the main girder web. Engineering.   The support metal fitting according to any one of claims 1 to 6, wherein the receiving metal fitting has a fixing nut fixed to a lower portion thereof and a push-up bolt that can be screwed to the fixing nut.   The support work according to any one of claims 1 to 7, wherein a scaffolding material is connected to the other end portion of the large pulling material so that the mounting angle can be adjusted.

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