JP6284561B2 - Suspension bolt reinforcement and suspension bolt reinforcement method - Google Patents

Description

  The present invention relates to a ceiling suspension reinforcement in which articles such as equipment are suspended from a ceiling by a plurality of suspension tools. More specifically, the present invention relates to all the suspension screws (suspending bolts) used for ceiling suspension. The present invention relates to a reinforcing tool and a reinforcing method.

  In the ceiling suspension using suspension bolts, for example, four suspension suspension bolts, which are male threads, are attached to the anchor and the female thread of the insert that are embedded in the ceiling slab, which is a fixed portion, and the other end of each suspension bolt When an article such as equipment (hereinafter referred to as “hanging object”) is connected to the apparatus, the article is installed in the air.

  With regard to ceiling installation equipment, etc., the building equipment seismic design and construction guidelines 2015 edition (Non-patent Document 1) shows a method of directly supporting the ceiling slab or using a steel suspension stand, and using suspension bolts. Support methods are not recommended. However, in practice, such a support method is often used, and even in Non-Patent Document 1, the seismic support of a lightweight device having a weight of 1 kN or less using a suspension bolt is considered to be lightweight. It is only necessary to ensure that the method is specified by the manufacturer of the device. "

  However, many manufacturers of equipment do not show a seismic support method for lightweight equipment, and the current situation is that an appropriate seismic support method for using suspension bolts has not been clarified.

  As a reinforcing means in the case of using a suspension bolt, one that increases the rigidity by covering the suspension bolt with a member such as a steel pipe has been proposed (Patent Document 1). Patent Document 1 uses a compressive force resistor to prevent buckling of a suspension bolt, but when an earthquake occurs and a suspended object (a suspension support device) shakes, the compression resistor slides. However, if the gap between the suspension bolt and the compression resistor disappears and contacts, a large shearing force is generated at the contact portion between the suspension bolt's ceiling slab surface and the compression resistor due to the displacement and excitation force caused by the swing of the suspension support device. Bolt shear failure is likely to occur.

  Further, as a method for increasing rigidity by combining steel materials and preventing buckling of suspension bolts, for example, the invention of Patent Document 2 has been proposed. However, according to this, when the suspension support device is displaced, a large shearing force is generated at the contact portion between the ceiling slab surface of the suspension bolt and the steel material, and the suspension bolt easily breaks.

  There has also been proposed a method in which a suspension bolt is covered with a steel material to increase rigidity, and an oblique member is provided to prevent displacement of the suspension support device so that shear force and bending moment are not applied to the suspension bolt (Patent Document 3). . However, if the slanting material withstands the excitation force during an earthquake so that the suspended object does not displace, shearing force is generated at the contact part of the slanting material on the ceiling slab surface and the hanger bolt, and the hanger bolt is sheared and destroyed. End up.

  Thus, as a reinforcement of the suspension bolt, in order to increase the rigidity, it is conceivable to cover the suspension bolt with a member having higher rigidity than the suspension bolt. For example, when covering a cylindrical tube (round pipe), When the pipe diameter is increased, the secondary moment of the round pipe is increased, so the bending stiffness against the bending moment of the round pipe increases. Even if is small, since a large shearing force is generated at the contact portion between the ceiling slab surface of the suspension bolt and the round pipe, the suspension bolt is shear broken.

  On the other hand, when the pipe diameter of the round pipe is reduced, the cross-sectional secondary moment of the round pipe is reduced, and the bending rigidity with respect to the bending moment of the round pipe is reduced. When a suspension device is vibrated by an earthquake, a large displacement occurs even with a small excitation force. When the displacement becomes large, the suspension bolt is plastically deformed by the bending moment at the contact point between the ceiling slab surface of the suspension bolt and the round pipe. Destroyed.

  That is, when a large excitation force is applied to a suspended object (equipment, etc.) due to an earthquake, if the diameter of the member to be covered (the pipe diameter of the round pipe) is large, the suspension bolt is sheared and destroyed, and if this diameter is small, The suspension bolt is bent and broken by plastic deformation due to the bending moment.

  Furthermore, in the earthquake-resistant design and construction method for non-patent literature 2 revised in 2012 (Non-Patent Document 2), as a practical seismic measure aimed at securing facility functions after an earthquake, the suspension or tilting of suspension support devices of 1 kN or less The prevention method is 9φ (W3 / 8 for inch screws) when the suspension length is 25cm or less, and 12φ (W1 / 2) suspension bolt for the suspension length of 25-30cm. (It is not possible to suspend the equipment with only the suspension bolt (no diagonal) if the suspension length is 30 cm or more).

  That is, if there are suspension support devices with a suspension length of 25 cm or less and 25 cm to 30 cm, the suspension bolts need both 9φ (W3 / 8) and 12φ (W1 / 2), and 9φ ( Metal fittings such as ceiling anchors applied to suspension bolts of W3 / 8) and 12φ (W1 / 2) must be used. Then, since there are two types of bolts having different diameters, the work must be distinguished from each other, the work efficiency may be reduced, and a construction error is likely to occur.

JP-A-10-205654 JP 2007-132122 A JP 2008-208687 A

Building Equipment Seismic Design and Construction Guidelines 2015 (issued by Japan Architecture Center) Seismic design and construction method for new building equipment (by the Air Conditioning and Sanitary Engineering Society)

  This invention is made | formed in view of the said problem, and makes it a subject to provide the suspension bolt reinforcement tool and suspension bolt reinforcement method for ceiling suspension which can respond to both a bending failure and a shear failure.

  It is another object of the present invention to provide a suspension bolt reinforcement tool and a suspension bolt reinforcement method that allow suspension bolts having the same diameter to be used when the suspension bolt has a suspension length of 30 cm or less.

  In order to solve the above-mentioned problems, the present invention increases the strength of the portion where the shearing force is concentrated in order to increase the shearing stress against the shearing force on the suspension bolt while increasing the bending stress against the bending moment on the suspension bolt. This is based on the technical idea of utilizing frictional force.

That is, the present invention is a suspension bolt reinforcing tool that reinforces a suspension bolt as a first side surface, a tubular member that covers the suspension bolt, and a first end portion that is attached to one end of the tubular member. A mounting member, a suspension bolt insertion portion into which a suspension bolt is inserted, a tubular member insertion portion to be inserted inside the tubular member, a ceiling contact surface that contacts the ceiling slab surface, and one end of the tubular member A first end attachment member having a hook-shaped surface that contacts the second end attachment member attached to the other end of the tubular member, the suspension bolt insertion portion into which the suspension bolt is inserted, A suspension bolt reinforcing tool comprising: a tubular member insertion portion that is inserted inside the tubular member; and a second end mounting member that has a hook-shaped surface that contacts the other end of the tubular member. provide.
As a second aspect, the present invention provides the above-described suspension bolt reinforcing tool in which the tubular member is made of SUS.
As a third aspect, the present invention provides the above-described suspension bolt reinforcing tool, wherein the suspension bolt is 9φ (W3 / 8).
As a fourth aspect, the present invention provides the above-described suspension bolt reinforcing tool, wherein the suspension bolt has a suspension length of 30 cm or less.
According to a fifth aspect of the present invention, there is provided a suspension bolt reinforcing method for reinforcing a suspension bolt for ceiling suspension, wherein the suspension bolt is covered with a tubular member, and between the tubular member and the ceiling slab surface, The one end mounting member is arranged so that the upper end surface thereof is in contact with the ceiling slab surface, and the tubular member is in contact with a bowl-shaped surface provided on the first end mounting member, and the tubular member is attached to the suspension bolt. A suspension bolt reinforcing method is provided, wherein a second end attaching member is attached to a lower end of the tubular member so that the member is supported.

  According to the present invention, the bending stress with respect to the bending moment applied to the suspension bolt is increased, and the shear stress with respect to the shearing force applied to the suspension bolt is increased.

It is a figure concerning the embodiment of the present invention. It is a figure concerning the tubular member of the present invention. (A) shows an example of a tubular member, (B) is a figure which shows the cross section at the time of attaching this tubular member to a suspension bolt. It is a figure concerning the edge part attachment member of this invention, (A) is a figure which shows an example of a 1st end part attachment member, (B) respectively shows an example of a 2nd edge part attachment member. It is a figure which shows the structure of reinforcement by this invention. It is a figure which shows the applied force, stress, and frictional force of reinforcement by this invention. It is a figure which shows the applied force, stress, and frictional force when not hanging a suspension bolt. It is a stress-strain diagram schematic diagram of a suspension bolt. It is a stress-deflection diagram schematic diagram of a suspension bolt. FIG. 4 is a diagram showing a relationship between a pipe diameter and a displacement δ-shear force F. It is a figure which shows the relationship between a pipe diameter and displacement (delta) -shear stress (tau). It is a figure which shows the test result in the case of conditions (1). It is a figure which shows the test result in the case of conditions (2). It is a figure which shows the test result in the case of conditions (3) (this invention). It is a figure which shows the ceiling suspension before attaching the reinforcement tool of this invention.

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

  FIG. 14 shows an example of a ceiling suspension in which the article (suspended object) 4 is suspended from the ceiling slab 5 by using four commonly used suspension bolts (suspenders) 6. The upper end of each suspension bolt 6 is inserted and fixed to the ceiling slab, and the article 4 such as a suspension device is fixed and fixed to the lower end of each suspension bolt 6 via the suspension fitting 18.

  FIG. 1 shows an example in which the ceiling suspension of FIG. 14 is reinforced with the suspension bolt reinforcement (1, 2, 3) according to the present invention. The suspension bolt reinforcing tool according to the present invention includes a tubular member 1, a first end mounting member 2, and a second end mounting member 3. The suspension bolt 6 is covered with the tubular member 1, and the first end attaching member 2 and the second end attaching member 3 are attached to one end and the other end of the tubular member 1, respectively. In FIG. 1, since the state of the ceiling suspension is shown from the front, only two suspension bolts are reinforced.

  The tubular member 1 is a member for covering the suspension bolt to increase the bending stress with respect to the bending moment applied to the suspension bolt during vibration, and is composed of a material having high rigidity. Moreover, it shall be a tubular tube, ie, a cylindrical tube, and can be attached only by inserting a suspension bolt. An example of the tubular member is shown in FIG. 2 (A), and a sectional view of the tubular member attached to the suspension bolt 6 is shown in FIG. 2 (B).

  If the tubular member is, for example, a round pipe made of SUS, it is preferable because rigidity can be obtained and the weight can be reduced and the cost can be kept low. A commercially available round pipe can also be used. Note that the inside (inner side surface) of the tubular member need not be particularly processed.

  When a tubular member is attached to the suspension bolt, the rigidity and bending stress of the suspension bolt are increased. However, if the suspended object is vibrated and displaced by an earthquake or the like in that state, the shearing force and bending moment are applied to the upper end (ceiling slab side) of the tubular member. Therefore, the suspension bolt is easily sheared or bent. Therefore, the portion where the shearing force and the bending moment are concentrated is reinforced by the first end mounting member.

  Before attaching the tubular member 1 to the suspension bolt, the first end attachment member 2 is attached to one end of the tubular member, that is, the end located on the ceiling slab side. An example of the first end mounting member is shown in FIG. The first end attachment member has a suspension bolt insertion portion 7 into which the suspension bolt is inserted. In order to make it easy to fasten the suspension bolt, which is a male screw, it is preferable to form the inner side of the suspension bolt insertion portion 7 with a female screw.

  A hook-shaped portion 8 is provided on the upper portion of the first end portion attachment member (the side located on the ceiling slab side when attached). The upper end surface 9 of the bowl-shaped portion is a surface that contacts the ceiling slab 5 (hereinafter referred to as “ceiling contact surface”).

  The first end attachment member 2 has a tubular member insertion portion 10 that is inserted into the inside of the tubular member below the hook-shaped portion 8. The outer diameter of the tubular member insertion portion is substantially the same as the inner diameter of the tubular member.

  The first end attachment member is screwed into the suspension bolt and attached so that the upper end surface 9 of the bowl-shaped portion 8 contacts the ceiling slab. As will be described later, the frictional force generated on the contact surface between the upper end surface 9 of the first end mounting member 2 and the ceiling slab is also used for reinforcement.

  After attaching the first end attachment member 2, the suspension bolt 6 is inserted into the tubular member 1, and the tubular member insertion portion 10 of the first end attachment member is inserted inside (through) the tubular member 1. Then, the upper end 11 (ceiling slab side) of the tubular member is brought into contact with a surface 12 (hereinafter referred to as “saddle-like surface”) located on the lower side (the side opposite to the upper end surface 9) of the saddle-like portion.

  After the tubular member 1 is attached to the suspension bolt 6, the second end attachment member 3 is attached to the lower end 13 of the tubular member (opposite side to the ceiling slab = ground side). The second end mounting member can have the same shape as the first end mounting member. At least the suspension bolt insertion portion 14 into which the suspension bolt is inserted and the tubular member insertion portion 15 to be inserted inside the tubular member. And a hook-like surface 16 that comes into contact with the other end of the tubular member (the lower end when attached to the suspension bolt and the ground side opposite to the ceiling slab). An example of the second end mounting member (having the same shape as the first end mounting member) is shown in FIG. In this example, the second end mounting member and the first end mounting member have the same shape, so that the hook-shaped surface 16 corresponds to the hook-shaped surface 12.

  The first end mounting member and the second end mounting member have rigidity and can be metal fittings.

  The first end attachment member, the tubular member, and the second end attachment member are attached to each suspension bolt. Since these can be installed by screwing or simply inserting, they can be easily installed not only as new equipment but also on existing ceiling suspension bolts.

  A hanging metal fitting 18 is attached to the lower end of each second end attachment member (the lower end when it is attached to a suspension bolt and on the ground side opposite to the ceiling slab), and the suspended object 4 is fixed thereto.

  The operation when the suspension bolt reinforcing tool according to the present invention is attached to the suspension bolt is as follows.

  When an exciting force is generated on a suspended object (suspending support device) due to an earthquake or the like (FIGS. 4 and 5), and a force W is applied to the lower end of the suspension bolt, a displacement of δ occurs at the lower end of the suspension bolt. At this time, a force W1 is applied to the suspension bolt, and a force W2 is applied to the tubular member. The relationship between W and W1, W2 is expressed by the following formula 1).

  W = W1 + W2 1) Formula

  Since the suspension bolt is fixed by the insert 17 and the upper first end mounting member, a bending moment M is generated at the lower end of the upper first end mounting member. The bending moment M is expressed by the following equation 2).

  M = W1 × L2 2) Formula

  Since the tubular member is inserted into and fixed to the upper first end attachment member, when a force W2 is applied to the lower end of the tubular member, a shearing force F is applied to the upper end of the tubular member. The shearing force F is expressed by the following 3) equation.

  F = W2 x L3 3) Formula

  At this time, since the upper first end mounting member is in contact with the ceiling slab surface, a frictional force F 'is generated. The frictional force F ′ is expressed by the following equation 4).

F ′ = μ × P 4) Formula μ: Friction coefficient between first end attachment member and ceiling slab surface P: Pressure at which first end attachment member contacts ceiling slab surface

  The shear force F of the tubular member to the suspension bolt, which is generated when an excitation force is applied to the suspension support device due to an earthquake or the like, is reinforced by the friction force F ′ generated at the contact surface between the first end mounting member and the ceiling slab. Do.

  When the frictional force F ′ is small with respect to the shearing force F and the shearing stress τ (FIG. 7) of the suspension bolt is small with respect to the shearing force F, the first end portion at the contact surface between the first end mounting member and the ceiling slab A side slip of the mounting member occurs, and a shear failure of the suspension bolt occurs.

  When the frictional force F ′ is small with respect to the shearing force F and the shearing stress τ (FIG. 7) of the suspension bolt is large with respect to the shearing force F, the suspension bolt does not cause shear failure, but the upper first end mounting member When the bending moment M generated at the lower end of the bolt is greater than the bending stress σ of the suspension bolt, the suspension bolt is plastically deformed and bending fracture occurs.

  When the frictional force F ′ is larger than the shearing force F, the excitation force to the suspension support device is large, and when the bending moment M generated in the suspension bolt due to the displacement δ of the suspension bolt becomes larger than the bending stress σ (FIG. 8), The bolt undergoes plastic deformation and bending failure occurs.

  When there is no first end attachment member (FIG. 6), when an excitation force is generated on the suspension support device, a bending moment M is generated by the displacement δ of the suspension bolt at the contact point between the ceiling surface and the suspension bolt, and the tubular member is further applied. When sliding by vibration and coming into contact with the suspension bolt, shear force F is generated on the suspension bolt. When the bending moment M exceeds the bending stress σ, bending failure occurs due to plastic deformation, and the shear force F is determined by the shear stress F 'of the suspension bolt. When it becomes larger, shear fracture occurs.

  Therefore, the suspension bolt is reinforced using the tubular member and the first end mounting member. When the frictional force between the first end mounting member and the ceiling slab surface is F ′, the suspension support device due to an earthquake or the like vibrates, and the shear force F is generated on the suspension bolt by the applied force W, the displacement δ Depending on how far the bending moment M is allowed, the diameter of the pipe to be reinforced can be different. That is, there is an optimal pipe diameter.

  For example, when shear force F is generated in the suspension bolt by the applied force W and the displacement of the suspension support device is allowed up to δ (FIG. 9), a tubular member having a large, medium and small pipe diameter is prepared. If it is used and reinforced, it will be displaced up to δ. Therefore, when the displacement is allowed up to δ, the pipe diameter must be medium or larger. However, considering the actual construction, it is necessary to finely adjust the mounting position of the suspension support device to some extent, so if the displacement for fine adjustment is δ small, the pipe diameter to be selected is between medium and large Must be used.

  For example, if a W3 / 8 suspension bolt is reinforced to obtain a strength equal to or greater than that of a W1 / 2 suspension bolt, the shear stress of the W1 / 2 suspension bolt is τ1 / 2. If the frictional force F ′ at the contact surface between the mounting member and the ceiling slab is larger than the shearing force F against the shearing stress τ1 / 2, and the allowable displacement δ of the suspension support device is, for example, δ, the pipe diameter is medium or larger Reinforcement is possible by using a round pipe (Fig. 10). At this time, the relationship between the shear stress τ and the shear force F is expressed by the following equation 5).

τ = F / A 5) Formula A: Effective sectional area of suspension bolt

(Experiment)
A static force test was performed on the present invention. In this test, the same suspension support device is supported by four suspension bolts under the following conditions (refer to FIG. 14 for the conditions (1) and (2), and refer to FIG. 1 for the condition (3)) and horizontally using the actuator. The displacement was repeatedly forced in the direction and the displacement and the load applied to the actuator were measured. The amount of displacement was ± 25 to ± 125 mm.

The test conditions are as follows.
Condition (1) Hanging bolt 300mm, W3 / 8. No reinforcement.
Condition (2) Hanging bolt 300mm, W1 / 2. No reinforcement.
Condition (3) Hanging bolt 300mm, W3 / 8. Reinforced according to the present invention.
In the reinforcement according to the present invention under the condition (3), a commercially available SUS round pipe having an inner diameter of 16φ was used as the tubular member. Moreover, both used the metal fitting of the same shape (shape shown in FIG. 3) as a 1st end part attachment member and a 2nd end part attachment member.

  The results of the test are shown in FIGS. 11 to 13, the x-axis indicates the displacement (mm) of the suspension device, and the y-axis indicates the load (kgf) generated when the suspension device is displaced.

Condition (1) (suspending bolt W3 / 8, no reinforcement) has a peak of strength at a displacement of ± 100mm, and when the displacement becomes larger, plastic deformation proceeds with the suspension bolt and the strength decreases, and the displacement of ± 125mm The fracture occurred.
Condition (2) (suspended bolt W1 / 2, no reinforcement) has a peak of strength at a displacement of ± 75mm, and when the displacement becomes larger, plastic deformation proceeds with the suspension bolt and the strength decreases, and the displacement of ± 125mm The fracture occurred.
In the condition (3) (suspending bolt W3 / 8, reinforced according to the present invention), there was a peak of strength at a displacement of ± 100 mm, but the suspension bolt did not break even at a displacement of ± 125 mm.

  From the above test results, it was confirmed that the strength against vibration increased when the reinforcement of the present invention was performed.

  According to the present invention, since it is possible to increase the shear stress with respect to the shearing force to the suspension bolt while increasing the bending stress with respect to the bending moment to the suspension bolt, it is possible to cope with both bending failure and shear failure. .

  Further, according to the present invention, when the suspension bolt has a suspension length of 30 cm or less, the suspension bolt is 9φ (W3 / 8), and the suspension bolt reinforcement of the present invention is attached to the suspension bolt. Since the same suspension bolt can be used (that is, the standard of the suspension bolt to be used can be unified), work efficiency can be improved and the strength can be improved.

  Furthermore, the present invention can be easily installed not only on new equipment but also on existing equipment, and can provide sufficient seismic reinforcement at a low cost and with great industrial applicability.

DESCRIPTION OF SYMBOLS 1 Tubular member 2 1st end part attachment member 3 2nd end part attachment member 4 Hanging thing 5 Ceiling slab 6 Hanging bolt 7 Hanging bolt insertion part 8 Hook-shaped part 9 Upper end surface 10 Tubular member insertion part 11 Upper end 12 of a tubular member Convex surface (surface located on the opposite side to the upper end surface in the bowl-shaped part, surface located on the ground side of the bowl-shaped part when the first end mounting member is attached to the suspension bolt)
13 Tubular member lower end 14 Suspension bolt insertion part 15 Tubular member insertion part 16 Saddle surface (surface located on the ceiling side of the scissor part when the second end attachment member is attached to the suspension bolt)
17 Insert 18 Hanging bracket

Claims (4)

A suspension bolt reinforcement that reinforces stress against shaking of a suspension bolt that is inserted and fixed into a ceiling slab,
A tubular member covering the suspension bolt;
A first end attachment member attached to one end of the tubular member,
An inner side is formed by a female screw corresponding to a suspension bolt that is a male screw, a suspension bolt is inserted, and a suspension bolt insertion portion that is screwed and fixed to the first end mounting member;
A tubular member insertion portion that is inserted into the tubular member and is fixed by inserting the tubular member into the first end mounting member;
A ceiling contact surface that contacts the ceiling slab surface;
A first end mounting member having a hook-shaped surface that contacts one end of the tubular member;
A second end attachment member attached to the other end of the tubular member,
A suspension bolt insertion portion into which the suspension bolt is inserted, and
A tubular member insertion portion to be inserted inside the tubular member;
A second end mounting member having a hook-shaped surface that contacts the other end of the tubular member;
Hanger bolt brace, characterized in that Ru comprising a.
The suspension bolt reinforcing tool according to claim 1, wherein the tubular member is made of SUS.
The suspension bolt reinforcing tool according to claim 1 or 2, wherein the suspension bolt is 9φ (W3 / 8) and the suspension length is 30 cm or less.
A suspension bolt reinforcement method for reinforcing stress against shaking of a suspension bolt for ceiling suspension, the upper end of which is inserted into a ceiling slab and fixed.
Covering the suspension bolt with a tubular member;
Between the tubular member and the ceiling slab surface, the upper end surface of the first end mounting member abuts against the ceiling slab surface, and the tubular member is formed on the bowl-shaped surface provided on the first end mounting member. The first end mounting member, which is arranged so as to be in contact with each other and formed on the inner side by a female screw corresponding to a suspension bolt that is a male screw, is screwed into the suspension bolt and fixed, and the tubular member is attached to the first end portion. Insert it into the member and fix it,
Hanger rod reinforcing method wherein the Ru attaching a second end fitting on the lower end of the tubular member as the tubular member is supported on the hanger rod.

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