JP7134000B2 - Sloped suspended ceiling structure - Google Patents

Description

The present invention relates to a sloped suspended ceiling structure.

2. Description of the Related Art Conventionally, suspended ceilings have been widely used as ceilings in buildings such as schools and offices. In a suspended ceiling, the ceiling base is supported by the upper structure with hanging bolts, and the ceiling material is fixed to the ceiling base.

If there is no horizontal restraint such as seismic braces, the suspended ceiling behaves like a pendulum motion due to the inertial force generated during an earthquake. There is a risk of damage due to collision with walls, equipment, and the like.

Therefore, in general, there is a method of installing earthquake-resistant braces (Patent Document 1 below) in order to restrain the behavior in the horizontal direction on the suspended ceiling, and a member assembled with steel materials so that it can behave integrally with the building frame ( A method of directly attaching the ceiling board to the so-called grape shelf) is adopted.

JP 2016-211177 A

However, the method of directly attaching the ceiling plate to the members assembled with steel so that it can act integrally with the frame requires many members and is heavy. However, even if it is possible, there is a problem that the cost will increase.

In addition, the method of installing braces to constrain the horizontal behavior of the suspended ceiling is to prevent the behavior of the ceiling plate in the in-plane direction (direction along the plate surface of the ceiling material) if the ceiling is installed horizontally. Therefore, the ceiling plate, which has high rigidity in the in-plane direction, behaves as a rigid floor. However, if the ceiling is tilted, the inertial force generated by the earthquake also works in the out-of-plane direction of the ceiling plate (the direction that intersects the plate surface of the ceiling material), so the rigidity is extremely low compared to the in-plane direction. There is a problem that it deforms in the out-of-plane direction and it is difficult to control the unstable behavior.

Accordingly, the present invention has been made in view of the above circumstances, and provides an inclined suspended ceiling structure capable of controlling the behavior of the ceiling material during an earthquake.

In order to achieve the above object, the present invention employs the following means.
That is, the inclined suspended ceiling structure according to the present invention includes a ceiling base to which the ceiling material forming the ceiling surface is fixed, suspension bolts to support the ceiling base from the upper structure, and horizontal inertia generated by an earthquake. Equipped with a brace that bears the force and a stiffener that resists the compressive force generated in the suspension bolt when a horizontal force acts on the ceiling material during an earthquake, and the horizontal force assumed at the time of design is Q, The vertical force borne by the i-th suspension bolt when the ceiling with the inclination angle θ is supported by the n suspension bolts is βi Q tan θ (where β1 + β2 + . . . + βn = 1), and the stiffener is arranged with strength to withstand the vertical force borne by the one suspension bolt .

In an inclined suspended ceiling structure constructed in this way, when horizontal force acts on the ceiling material during an earthquake, the suspension bolts resist the vertical tensile force and the stiffeners resist the vertical compressive force. resist. As a result, the force is dispersed into an in-plane force along the plate surface of the ceiling material and a vertical force. As a result, the in-plane force acting as a rigid floor acts on the part where movement is restrained by the earthquake-resistant braces, which contributes to the stable movement of the entire ceiling material in the horizontal direction.

Further, in the inclined suspended ceiling structure according to the present invention, it is preferable that the stiffeners are connected only to the hanging bolts.

The inclined suspended ceiling structure according to the present invention allows the behavior of the ceiling material to be controlled during an earthquake.

FIG. 2 illustrates a sloped suspended ceiling structure according to an embodiment of the present invention; FIG. 4 is a diagram illustrating forces acting on a sloped suspended ceiling structure according to an embodiment of the present invention; FIG. 4 is a diagram illustrating forces acting on a sloped suspended ceiling structure according to an embodiment of the present invention; It is a top view which shows the experimental apparatus of the horizontal force application unit test to the ceiling-belt receiving direction performed using the inclined suspended ceiling structure which concerns on one Embodiment of this invention. 5 is a field view taken along line X1-X1 of FIG. 4; FIG. It is a top view which shows the experimental apparatus of the horizontal force application unit test to the ceiling direction which was performed using the inclined suspended ceiling structure based on one Embodiment of this invention. 7 is a view taken along line X2-X2 of FIG. 6; FIG. 7 is a view taken along line Y2-Y2 of FIG. 6. FIG. FIG. 3 is a diagram showing an experimental apparatus for a buckling strength test performed using a suspended member of an inclined suspended ceiling structure according to an embodiment of the present invention; 5 is a graph showing test results of a buckling strength test performed using a suspension member (with a support member) of an inclined suspended ceiling structure according to an embodiment of the present invention;

A sloped suspended ceiling structure according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 illustrates a sloped suspended ceiling structure according to one embodiment of the present invention.
As shown in FIG. 1, the inclined suspended ceiling structure 100 according to the present embodiment includes an upper structure 1 such as an upper floor, a ceiling base 2, a ceiling material 3, a brace 4, and a suspension member 5. , is equipped with

The ceiling base 2 has a plurality of joists 21 and a plurality of joist receivers 22. - 特許庁The plurality of joists 21 are arranged at predetermined intervals in one horizontal direction. The plurality of ceiling joist receivers 22 are arranged at predetermined intervals in the other horizontal direction orthogonal to the ceiling joists 21 and provided on the plurality of ceiling joists 21 .

The ceiling material 3 is formed in a flat plate shape and fixed to the joists 21 of the ceiling base 2. - 特許庁The ceiling material 3 is arranged at an inclination angle of about 30° or less with respect to the horizontal plane. The lower surface of the ceiling material 3 forms a ceiling surface 31. - 特許庁

The brace 4 is arranged to be inclined with respect to the horizontal plane. A pair of braces 4 are arranged in a substantially V shape. The angle of inclination of the brace 4 with respect to the horizontal plane is preferably 45-60°.

The upper ends of the braces 4 are fixed to the upper structure 1 via brace upper fixtures 41 . The lower ends of the braces 4 are fixed to the ceiling base 2 via brace lower fixtures 42 .

The brace upper fixture 41 has an upper portion fixed to the upper structure 1 and a lower portion fixed to the brace 4 . The inclination angle of the brace 4 can be adjusted by the brace upper fixture 41 when the brace 4 is attached.

The brace lower fixture 42 has a pair of braces 4 fixed to its upper part and a lower part fixed to the ceiling material 3 .

A fitting recess 42a recessed upward is provided at the lower end of the brace lower fixture 42 . The ceiling lining 21 of the ceiling base 2 can be fitted into the fitting recess 42a.

The suspension member 5 has stiffeners 50 and suspension bolts 60 . A plurality of suspension members 5 are installed at intervals in the horizontal direction.

The stiffener 50 extends vertically and has a tubular shape . In this embodiment, the stiffeners 50 are made of square pipes.

The suspending bolt 60 is inserted through the interior of the stiffener 50 . Nuts 61 are fastened to the upper and lower parts of the stiffening member 50 via washers or the like, and the stiffening member 50 and the hanging bolt 60 are connected.

The upper and lower ends of the suspension bolt 60 protrude upward and downward from the upper and lower ends of the stiffener 50, respectively. The upper end of the hanging bolt 60 is fixed to the upper structure 1 . A lower end portion of the hanging bolt 60 is connected to the ceiling joist receiver 22 of the ceiling base 2 or the like via a hanging member connecting metal fitting 63 .

The hanging bolt 60 has a predetermined tensile strength. The stiffener 50 resists the compressive force generated in the suspension bolt 60 when horizontal force acts on the ceiling material 3 during an earthquake.

In the inclined suspended ceiling structure 100 configured in this way, when horizontal force acts on the ceiling material 3 during an earthquake, the suspension bolts 60 resist the tensile force in the vertical direction, and the stiffeners 50 move vertically. resists the compressive force of This disperses the force into an in-plane force and a vertical force. As a result, a force in the in-plane direction acts as a rigid floor on the portion where the brace 7 restrains the movement, which contributes to the stable movement of the entire ceiling material 3 in the horizontal direction.

Further, since the stiffener 50 is provided in the vicinity of the hanging bolt 60, it is possible to reliably give rigidity to the hanging bolt 60 in the compression direction.

Moreover, since the stiffening member 50 and the hanging bolt 60 are connected and integrated, the buckling of the hanging bolt 60 due to the compressive force is reliably suppressed.

A fitting recess 42a into which the joist 21 of the ceiling base 2 can be fitted is formed in the brace lower fixture 42 to which the lower end of the brace 4 is connected. Therefore, compared to the case where the braces 4 are directly fixed to the joists 21, the braces 4 can be installed without being restricted by the positions of the members such as the joists 21.

(calculation results, static loading test results)
Next, calculation results and static loading test results for the inclined suspended ceiling structure will be described.
2 and 3 are diagrams for explaining forces acting on a slanted suspended ceiling structure.
As shown in Fig. 2, the ceiling slope θ = 0 to 30° with respect to the horizontal plane, the installation angle α of the braces = 45 to 60° from the horizontal plane, and the buckling-reinforced hanging member that can bear the axial force in the vertical direction. Consider a model in which (suspension members of the present embodiment) are installed at arbitrary numbers and positions.

When a horizontal force _Q0 is applied in the horizontal direction so that the entire ceiling surface moves horizontally in the direction of a, the horizontal reaction force on the ceiling surface is generated only at the lower end of the V-shaped brace, and the ceiling plate A force is transmitted to (the ceiling material of the present embodiment) in the in-plane direction where the rigidity is high. A vertical axial force is generated in the hanging member. Let β be an arbitrary coefficient determined by the number and position of the hanging members, force acts as shown in FIG. Note that β ₁ +β ₂ + . . . β _n =1.

In addition, although the stiffening member resists the vertical compressive force, the constant axial rigidity causes slight vertical displacement, so that it has potential energy corresponding to the displacement with respect to the horizontal force. Assuming that the horizontal force to be converted into this potential energy is ω and the other horizontal force is Q, Q=Q ₀ -ω.

The relationship between the axial forces A and B borne by each brace with respect to the application of the horizontal force Q to the ceiling surface is as shown in FIG. 3 and the following equations (1) and (2).

From the formula (1), the axial force B is given by the following formula (3).

Substituting equation (3) into equation (2) yields equation (4) below.

Substituting equation (4) into equation (3) yields equation (5) below.

_{Let Qf} be the horizontal load that causes buckling when the ceiling surface is horizontal (θ = 0). Assuming that Q _θb , brace buckling is proportional to the axial force unless the end fixing conditions, the sectional performance of the member and the length are changed, so that the following equations (6) and (7) are obtained.

Table 1 shows the test results for the horizontal load Qf that causes buckling when the ceiling surface is horizontal (θ ₌ 0), the vertical length of the brace is 1500 mm, and the installation angle of the brace is 60°.

Table 2 shows the results of horizontal load values that cause brace buckling at ceiling slopes of 10°, 20°, and 30° calculated from Table 1 using equations (6) and (7) from the above test results. .

Table 3 shows the results of static loading tests performed at ceiling slopes of 10°, 20°, and 30°.

As shown in Tables 1 to 3, the estimated buckling load of the brace substantially agrees with the calculated estimated value and the test result when considering the loss ω of the horizontal applied force due to slight vertical movement.

Regarding the rigidity of the brace, a static load test was performed by setting the brace specifications, length, and installation angle, setting the ceiling slope to 0° (horizontal), 10°, 20°, and 30°, and applying force in the horizontal direction. As shown in Table 4, the test results of the initial stiffness values of 1 are almost constant regardless of the ceiling inclination.

Next, the static loading test performed above will be described.
FIG. 4 is a plan view showing an experimental apparatus for a horizontal force application unit test in the direction of receiving a joist using an inclined suspended ceiling structure. 5 is a view taken along the line X1-X1 of FIG. 4. FIG. FIG. 6 is a plan view showing an experimental apparatus for a horizontal force application unit test in the direction of the joists using an inclined suspended ceiling structure. FIG. 7 is a view taken along line X2-X2 of FIG. 8 is a view taken along the line Y2-Y2 of FIG. 6. FIG.
As shown in Figs. 4 to 8, a static loading test of a tilted suspended ceiling structure was performed using a hydraulic loading tester with a width of 5.6 m, a depth of 4.8 m, and a height of 3.7 m. did The setting angle of the ceiling support structural member was horizontal, and the inclination angles of the ceiling surface were changed to 10°, 20°, and 30°.

(Buckling resistance test)
Next, a unidirectional load test in the direction of axial compression of suspension members (including stiffeners and suspension bolts) of the inclined suspended ceiling structure will be described.
FIG. 9 shows an experimental apparatus for a buckling strength test using a hanging member.
The length of the suspension member (distance between fulcrums) is 3,000 mm, the suspension bolt is mild steel W3/8 (JIS standard product), the stiffener is a square steel pipe 19 x 19 x 1.2 mm, and the nut is W3/8. and flat washers.

As a static load test in which an axial compressive force generated by horizontal inertial force due to seismic motion is applied, assuming a vertical seismic intensity of 1.0 (upward), the extension direction of the test body (suspension member of this embodiment) is horizontal. set in the direction
In addition, since the test body is affected by gravity in a vertical downward direction, a support member that freely slides horizontally was installed near the center of the test body.

As shown in FIG. 10, the test results show that the displacement in the axial direction up to about 0.4 kN is 0 to 16 decimal places as a measurement limit, and if the force is continued in the axial direction, the center of the specimen is buckled to the apex.

Since one or more hanging members are arranged per ^1m2 , one hanging member bears the load when the unit area mass of the ceiling is 25kg/ ^m2 and an earthquake causes an acceleration of 2.2G in the horizontal direction. The vertical force P _h is given by the following formula (8) when the inclination angle of the ceiling is 30°.

As shown in FIG. 10, up to an axial force of 0.4 kN, there is almost no displacement in the axial direction of the material, so the material bears a smaller axial force of 0.31 kN. Under the conditions of a vertical seismic intensity of 1.0 and a horizontal seismic intensity of 2.2, it is assumed that the ceiling surface has sufficient axial rigidity to control the behavior in the vertical direction.

It should be noted that the various shapes, combinations, etc., of the constituent members shown in the above-described embodiment are merely examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

For example, in the embodiment shown above, the braces 4 are fixed to the upper structure 1 and the ceiling base 2 via the upper brace fixtures 41 and the lower brace fixtures 42, respectively, but the present invention is not limited to this. . The brace 4 may be fixed directly to the upper structure 1 and the ceiling base 2 .

Moreover, in the embodiment shown above, the hanging bolt 60 is inserted through the stiffener 50, but the present invention is not limited to this. The stiffening member 50 is preferably provided in the vicinity of the hanging bolt 60. For example, the stiffening member 50 is arranged adjacent to the hanging bolt 60, and the stiffening member 50 and the hanging bolt 60 are connected by a connecting metal fitting (not shown). etc. may be connected.

Reference Signs List 1 Upper structure 2 Ceiling base 3 Ceiling material 4 Brace 5 Suspension member 21 Ceiling 22 Ceiling support 41 Brace upper fixture 42 Brace lower fixture 42a Fitting recess 50 Stiffening Material 60... Suspension bolt 63... Suspension member connection metal fitting 100... Inclined suspended ceiling structure

Claims (2)

a ceiling substrate to which the ceiling material forming the ceiling surface is fixed;
hanging bolts for supporting the ceiling base from the upper structure;
a brace that bears the horizontal inertial force generated by an earthquake;
a stiffener that resists the compressive force generated in the suspension bolt when a horizontal force acts on the ceiling material during an earthquake ;
Let Q be the horizontal force assumed at the time of design, and when the ceiling with the inclination angle θ of the ceiling surface is supported by the n suspension bolts, the vertical force borne by the i-th suspension bolt is βi· Q tan θ (where β1 + β2 + … + βn = 1),
The inclined suspended ceiling structure , wherein the stiffeners are arranged with strength to withstand the vertical force borne by the one suspension bolt . 2. The sloped suspended ceiling structure of claim 1, wherein said stiffeners are connected only to said hanger bolts.

Images