JP6783346B2 - Extruded cement board - Google Patents

Description

The present invention the surface of the extruded cement plate attached to skeleton of the building, relates press-molded cement board for mounting the like exterior member or equipment and piping, defective portions due to particular drilling extrusion cement board on press-molded cement board that stress concentration to enable you to prevent a reduction in strength was a factor of to.

Extruded cement boards are lightweight and have high strength, so they are widely used as exterior wall materials for buildings. In an outer wall structure using an extruded cement plate, an angle as a base material is generally fixed to the building frame, and a Z clip or the like fastened to the back surface of the extruded cement plate is locked to the angle for extrusion molding. A cement board is attached.

Attaching finishing materials such as tiles and stones to the surface of the extruded cement board, or providing through holes that penetrate the front and back of the extruded cement board, and using these as ventilation openings and piping openings. Is being done. When the finishing material is attached to the surface of the extruded cement plate, bolt holes and screw holes must be formed in the extruded cement plate, and the extruded cement plate has defects due to these holes. When the extruded cement board is provided with a ventilation port or a piping port, these are the defective portions of the extruded cement board.

For example, in Patent Document 1, a recess is formed on the surface portion of an extruded cement plate, a reinforcing metal fitting is arranged on the back of the recess, and the reinforcing metal fitting is fixed to the fastener via an anchor bolt in the recess, and the fastener is fixed. The finishing material is attached by fitting the dowel pins provided in the above into the holes provided in the end faces of the finishing material.

Jikkai Sho 63-51039

When a finishing material is attached to the surface as in Patent Document 1 or a tensile stress acts on the outside of the extruded cement plate to cause bending deformation in a state where there is a defect due to the formation of a ventilation port or the like. Stress concentrates on the defective part. When stress is concentrated on the defective portion, the bending strength of the extruded cement plate is reduced by about 30% as compared with the case where the defective portion does not exist, and the fracture may occur with a force smaller than the original bending strength. .. Therefore, the allowable stress is designed to be lower than the original stress. Designing with a lower allowable stress leads to a smaller support span of the extruded cement board, which causes problems such as insufficient support span between beams when vertically installed in a building with a large floor height, for example. Was there.

The present invention aims to provide a conventional view of the problems of the technology, extrusion defective portions exist in the molded cement board out pressing also to enable you to maintain a high yield strength of extruded cement board forming cement board To do.

The extruded cement plate of the present invention is an extruded cement plate in which a plurality of hollow portions are arranged side by side in one direction and has through holes for passing equipment or pipes penetrating the front and back surfaces. A single groove portion extending substantially linearly is formed along the groove, the through hole is formed in the groove portion, and both side ends of the groove portion are inclined inward toward the groove bottom, and the groove portion is viewed in cross section. The groove is formed in an inverted trapezoidal shape, and the groove portion overlaps a plurality of hollow portions in the thickness direction of the extruded cement plate and exceeds two adjacent hollow portions of the overlapping hollow portions in the width direction of the extruded cement plate. and is characterized in that in is formed.

In the extruded cement plate of the present invention, a groove portion extending substantially linearly along the hollow portion is formed on the surface portion of the extruded cement plate, and a through hole is formed in the groove portion. There is no decrease in strength due to stress concentration. Therefore, it can be designed without lowering the allowable stress of the extruded cement plate, and high yield strength can be maintained. As a result, it is not necessary to reduce the support span of the extruded cement plate, and the degree of freedom in construction of the extruded cement plate can be maintained.

In the extruded cement plate, the thickness of the extruded cement plate corresponding to the groove is preferably 40 to 100 mm. If the thickness of the extruded cement plate corresponding to the groove is 40 to 100 mm, the high strength of the extruded cement plate can be maintained.

Of the total width of the extruded cement plate, when the width excluding the groove is W1 and the width of the groove is W2, it is preferable that W1> W2 is satisfied. When the width of the extruded cement plate excluding the groove portion exceeds the width of the groove portion, it is possible to maintain an advantage over the extruded cement plate having no groove portion.

When the distance from the centroid of the extruded cement plate to the groove bottom of the groove is A, and the distance from the centroid to the surface of the extruded cement plate is B, A / B = 0.4 to 0.7. It is preferable to satisfy. In this case, it is possible to reliably prevent a decrease in strength due to stress concentration in the through hole.

The groove may be formed on both the front side and the back side of the extruded cement plate. In this case, the high yield strength of the extruded cement plate can be reliably maintained.

According to the present invention, since the strength does not decrease due to the stress concentration in the defective portion or the through hole, the design can be performed without lowering the allowable stress degree, and a high proof stress can be maintained. As a result, it is not necessary to reduce the support span of the extruded cement plate, and the degree of freedom in construction of the extruded cement plate can be maintained.

It is sectional drawing which shows the extruded cement board which concerns on 1st Embodiment of this invention. FIG. 1 is an end view, a plan view, and a side view of the extruded cement plate of FIG. 1. It is explanatory drawing for demonstrating the relationship between the distance from the centroid and the degree of stress. It is sectional drawing which shows the extruded cement board which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the extruded cement board which concerns on 3rd Embodiment of this invention. It is sectional drawing and the enlarged view of the main part which show the exterior member mounting structure of the extruded cement board which concerns on 1st Embodiment of this invention. It is sectional drawing and the front view which show the exterior member mounting structure of the extruded cement board which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the conventional extruded cement board. 8 is an end view, a plan view, and a side view of the extruded cement plate of FIG. 8.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an extruded cement plate 1 according to the first embodiment of the present invention, and FIG. 2 is an end view, a plan view, and a side view of the extruded cement plate 1 of FIG. The extruded cement plate 1 is an exterior material that is attached to the building frame by a vertical construction method or a horizontal construction method. The extrusion-molded cement plate 1 is manufactured by extruding a mixture of water, cement, aggregate, fibers and the like with an extrusion molding machine, curing and curing the mixture, and then cutting the mixture to a predetermined size. The extruded cement plate 1 is formed with a plurality of hollow portions 2 having a rectangular cross section parallel to each other in the longitudinal direction, which is the extrusion direction. By forming these plurality of hollow portions 2, a plurality of partition walls 3 connecting the front surface side base material 1a and the back surface side base material 1b of the extruded cement plate 1 are formed. In the following description, the upper side of the extruded cement plate 1 in the drawing is the outside of the state of being attached to the building, and the lower side is the inside of the state of being attached.

In the outer wall structure using the extruded cement plate 1, an angle as a base material is generally fixed to the building frame, and a Z clip or the like fastened to the back surface of the extruded cement plate 1 is locked to the angle. An extruded cement plate 1 is attached.

The extruded cement plate 1 of the present embodiment is formed with a plan-view circular through hole 4 penetrating the front and back in the central portion in the width direction. The through hole 4 serves as a ventilation port or a piping port for passing equipment or piping penetrating the front and back surfaces, and is formed so that the diameter D is Wm> D. The through hole 4 of the present embodiment has a circular shape in a plan view, but may have another shape. On the outer surface portion 1h of the extruded cement plate 1, one groove portion 5 extending substantially linearly along the hollow portion 2 is formed. As shown in FIG. 1, the groove portion 5 has left and right side ends 5b and 5b that incline inward toward the groove bottom 5a, and is formed in an inverted trapezoidal shape in cross-sectional view. In the present embodiment, the number of grooves 5 is one, but a plurality of grooves may be formed on the surface portion 1h of the extruded cement plate 1.

As shown in FIGS. 1 and 2, the through hole 4 is formed in the groove portion 5 at a substantially central portion in the width direction. The through hole 4 is housed in the groove 5, so that the diameter D of the through hole 4 is smaller than the groove bottom width Wm of the groove 5. The thickness S1 of the extruded cement plate 1 to which the present embodiment is applied is about 50 to 120 mm, and the thickness S2 of the extruded cement plate 1 corresponding to the groove 5 is 40 to 100 mm.

When the extruded cement plate 1 is bent and deformed by an external force, the degree of stress increases as the portion is farther from the center of gravity N. Here, the center of gravity means the position of the center of gravity in the thickness direction of the extruded cement plate 1. Therefore, when the extruded cement plate 1 having the groove 5 provided on the surface portion 1h is bent and deformed so that the outside of the groove 5 becomes a tensile stress as in the present embodiment, the groove bottom of the extruded cement plate 1 is subjected to bending deformation. The surface portion 1ha (hereinafter, this is referred to as an outer surface portion) other than 5a is a portion that produces the maximum stress degree. The groove bottom 5a is a portion that generates a stress degree smaller than that of the outer surface portion 1ha.

Therefore, the fracture starts from the outer surface portion 1ha of the extruded cement plate 1, and the strength of the extruded cement plate 1 is determined based on the properties of the outer surface portion 1ha. Even when the extruded cement plate is provided with a through hole that can cause a decrease in strength, if the through hole 4 is present in the groove 5 as in the present embodiment, the outer surface portion 1ha of the extruded cement plate 1 is provided. Can bear the generated stress. As a result, it is possible to prevent a decrease in strength due to stress concentration in the through hole 4. This effect is particularly effective when bending deformation due to tensile stress occurs on the grooved surface of the extruded cement plate.

As described above, the outer surface portion 1ha of the extruded cement plate 1 is the portion that produces the maximum stress degree. When the ratio of the groove portion 5 in the surface portion 1h is increased, the cross-sectional coefficient value when there is no through hole becomes small, and the advantage over the extruded cement plate without the groove portion is reduced. Therefore, of the total width W of the extruded cement plate 1, the following formula is satisfied when the width of the outer surface portion 1ha excluding the groove portion 5 is W1 and the width of the groove portion 5 is W2.
W1> W2
The width W1 of the outer surface portion 1ha excluding the groove portion 5 is the total width of the portions divided into a plurality of portions by the groove portion 5 as shown in FIG. The width W2 when a plurality of grooves are formed is the sum of the widths of all the grooves. In the present embodiment, as shown in FIG. 1, there are two inclined portions 6 which are obliquely inclined at both left and right ends of the extruded cement plate 1. The sum of the widths W2 of all the grooves includes the width of all the portions recessed inward from the outer surface 1 g of the extruded cement plate 1.

The difference in the degree of stress between the outer surface portion 1ha of the extruded cement plate 1 and the groove bottom 5a corresponds to the ratio of the distance of the extruded cement plate 1 from the centroid N with reference to the explanatory view of FIG. I found that. The relationship of stress degree is (distance from the center of gravity N to the groove bottom) / (distance from the center of gravity N to the outer surface) = (bending stress degree generated at the groove bottom) / (bending stress generated at the outer surface portion). Degree). Therefore, the degree of bending stress of the extruded cement plate 1 can be calculated based on the cross-sectional shape of the extruded cement plate 1, its dimensions, and the center of gravity N.

The following equation is satisfied when the distance from the center of gravity N of the extruded cement plate 1 to the groove bottom 5a is A and the distance from the center of gravity N to the outer surface 1g is B.
A / B = 0.4 to 0.7
A / B = about 0.7 is a boundary point for avoiding stress concentration in the through hole 4, and by setting A / B = 0.4 to 0.7, stress concentration in the through hole 4 is a factor. It is possible to surely prevent the decrease in strength. If the A / B is 0.7 or less, the stress in the groove 5 is 70% or less of the outermost surface, so that stress concentration does not occur, but if the A / B is 0.7 or more, the stress concentration cannot be avoided. However, if it is 0.4 or less, the remaining thickness of the groove 5 becomes thin, which may affect the strength in the width direction.

When a through hole is formed in a conventional extruded cement plate, the strength is reduced by about 30% due to stress concentration in the through hole, but the groove portion 5 in which the stress is 30% or more smaller than that of the surface portion 1h of the extruded cement plate 1. By forming the through hole 4 inside, it is possible to prevent the strength of the extruded cement plate 1 from being lowered due to the influence of stress concentration.

In the case of the extruded cement plate 1 of the present embodiment, a groove portion 5 extending substantially linearly along the hollow portion 2 is formed on the surface portion 1h of the extruded cement plate 1, and a through hole 4 penetrating the front and back surfaces is formed. Since it is formed in the groove 5, the strength does not decrease due to stress concentration in the through hole 4. Therefore, the extruded cement plate 1 can be designed without lowering the allowable stress, and a high yield strength can be maintained. As a result, it is not necessary to reduce the support span of the extruded cement plate 1, and the degree of freedom in construction of the extruded cement plate 1 can be maintained.

Since the thickness S2 of the extruded cement plate 1 corresponding to the groove 5 is 40 to 100 mm, the high strength of the extruded cement plate 1 can be maintained. Of the total width W of the extruded cement plate 1, the width W1 of the outer surface portion 1ha excluding the groove 5 exceeds the width W2 of the groove, so that the advantage over the extruded cement plate without the groove can be maintained. ..

Since the distance A from the center of gravity N of the extruded cement plate 1 to the groove bottom 5a and the distance B from the center of gravity N to the outer surface 1 g satisfy A / B = 0.4 to 0.7, they penetrate. It is possible to reliably prevent a decrease in strength due to stress concentration in the holes 4.

Conventionally, in order to increase the support span of the extruded cement plate, the thickness of the extruded cement plate has been increased. As a result, the cross section becomes large, and the cost increases due to the increase in the burden on the work site due to the increase in weight. Since the extruded cement plate 1 of the present embodiment maintains high strength without increasing the thickness, the weight does not increase and the cost does not increase.

Examples of the present invention will be described. The present invention is not limited to this example. The limit load of the conventional extruded cement plate 40 (with through holes) as a comparative example shown in FIGS. 8 and 9 and the extruded cement plate 1 (with through holes) of the above embodiment as an example is calculated. Both the extruded cement plate 40 of the comparative example and the extruded cement plate 1 of the example have a thickness S1: 80 mm, an overall width W: 590 mm, a length L (support span) 2000 mm, a diameter D of through holes 4 and 41: 100 mm, and penetration. The positions of the holes 4 and 41 were those centered between the supports.

The support span of the extruded cement plate is L, the strength of the extruded cement plate is σ, the cross-sectional coefficient of the effective cross section is Z, and when a load K acts on the center of the support span L of the extruded cement plate, the bending stress From the calculation formula, the limit load P is expressed by the following formula.
P × L / (4 × Z) ≦ σ × 0.7
(0.7 is the reduction rate considering the effect of stress concentration due to cross-sectional defects)
P ≦ (σ × 0.7 × 4 × Z) / L

(Comparison example)
The limit load P1 of the comparative example is calculated. The cross-sectional area before forming the through hole, the cross-sectional coefficient Z of the effective cross-sectional portion, and the strength σ of the extruded cement plate are as follows.
Cross-sectional area before forming a through hole: 241 cm ²
Section modulus of effective cross section Z: 416 cm ³
Strength of extruded cement board σ: 17.6N / mm ²

P1 ≦ (σ × 0.7 × 4 × Z) / L
P1 ≦ (17.6 × 0.7 × 4 × 416000) / 2000
P1 ≤ 10250N

(Example)
The limit load P2 of the embodiment is calculated. The cross-sectional area before forming the through hole, the cross-sectional coefficient Z of the effective cross-sectional portion, and the strength σ of the extruded cement plate are as follows.
Cross-sectional area before forming a through hole: 237 cm ²
Section modulus of effective cross section Z: 350 cm ³
Strength of extruded cement board σ: 17.6N / mm ²

P2 ≦ (σ × 4 × Z) / L
P2 ≦ (17.6 × 4 × 350,000) / 2000
P2 ≤ 12320N

From the calculation results, it is recognized that the example in which the through hole 4 is formed in the groove 5 has a limit load P2 that is about 1.2 times the limit load P1 of the comparative example without the groove. That is, the limit load can be increased by about 1.2 times without increasing the thickness and the cross-sectional area. As a result, even if the through hole 4 is present, the support span L of the extruded cement plate 1 can be maintained without increasing the thickness.

FIG. 4 is a cross-sectional view showing the extruded cement plate 10 according to the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that grooves are formed on both the front side and the back side of the extruded cement plate 10. The first groove portion 11, which is the same groove portion as in the first embodiment, is formed on the outer surface portion 1h of the extruded cement plate 10, and the first groove portion 11 is also formed on the inner surface portion 1h of the extruded cement plate 10. A second groove portion 12 having the same shape and the same size is formed. The configuration is the same as that of the first embodiment except that the second groove portion 12 is formed, and the same reference numerals are given to the common configurations. According to the extruded cement plate 10 of the present embodiment, the strength of the front and back surfaces of the extruded cement plate 10 can be reliably maintained.

FIG. 5 is a cross-sectional view showing an extruded cement plate 15 according to a third embodiment of the present invention. In the present embodiment, a through hole 17 larger than that of the first embodiment is formed in the groove portion 16. The side end of the groove portion 16 is formed along the thickness direction, and the groove portion 16 has a rectangular shape in a cross-sectional view. The main configurations other than the groove portion 16 and the through hole 17 are common to those of the first embodiment, and the same reference numerals are given to the common configurations. Even when a larger through hole 17 is formed in the extruded cement plate 15, the strength does not decrease due to stress concentration in the through hole 17. Therefore, the extruded cement plate 15 can be designed without lowering the allowable stress, and a high yield strength can be maintained. Regarding the relationship between the size of the groove 16 and the size of the through hole 17, when the width of the groove 16 is Wm and the diameter of the through hole 17 is D, the strength is reduced by satisfying the relational expression Wm> D. It can be reliably prevented.

FIG. 6 is a cross-sectional view showing an exterior member mounting structure 20 of an extruded cement plate according to a first embodiment of the present invention. The exterior member mounting structure 20 of the extruded cement plate of the present embodiment is formed on an extruded cement plate 22 in which a plurality of hollow portions 21 are arranged side by side in one direction and an outer surface (surface) 22 g of the extruded cement plate 22. It is provided with a finishing material 23 which is an installed exterior member, and an attachment means 24 for fixing the finishing material 23 to the outer surface 22 g of the extruded cement plate 22.

The finishing material 23 is fixed to the outer surface 22 g of the extruded cement plate 22 with an adhesive. Two groove portions 25 having a rectangular cross section extending substantially linearly along the hollow portion 21 are formed on the outer surface portion 22h of the extruded cement plate 22. One end of the fall-prevention iron wire 27 is fixed in each groove 25 by a tapping screw 26, and a defective portion 22a by the tapping screw 26 is formed in the groove bottom 25a of each groove 25. The other end of the fall-prevention iron wire 27 is fixed to the back surface of the finishing material 23. By forming the defective portion 22a in the groove bottom 25a of the extruded cement plate 22 in this way, the finishing material 23 is fixed to the extruded cement plate 22. As long as the finishing material can be fixed, the number of grooves and mounting means is not limited. The position of the defective portion 22a is within the range corresponding to the hollow portion 21 in the groove bottom 25a in the groove portion 25. As a result, it is possible to make it more difficult for stress to be concentrated on the defective portion 22a.

The extruded cement plate 22 used for the exterior member mounting structure 20 of the extruded cement plate can obtain the same effect as the extruded cement plate 1 of the first embodiment. This point will be described.

The thickness S1 of the extruded cement plate 22 to which the present embodiment is applied is about 50 to 120 mm, and the thickness S2 of the extruded cement plate 22 corresponding to the groove 25 is 40 to 100 mm. When the extruded cement plate 1 is bent and deformed by an external force, the degree of stress increases as the portion is farther from the center of gravity N. Therefore, when the extruded cement plate 22 provided with the plurality of groove portions 25 on the surface portion 22h is bent and deformed so that the outer side having the groove portions 25 becomes a tensile stress as in the present embodiment, the outer surface portion 22ha is the maximum. It is the part that generates the degree of stress. On the other hand, the groove bottom 25a is a portion that generates a stress degree smaller than that of the outer surface portion 22ha.

Therefore, the fracture starts from the outer surface portion 22ha of the extruded cement plate 22, and the strength of the extruded cement plate 22 is determined based on the properties of the outer surface portion 22ha. Even when the extruded cement plate 22 has a defective portion 22a that causes a decrease in strength, if the defective portion 22a is present in the groove portion 25 as in the present embodiment, the extruded cement plate 22 can be formed. The generated stress can be borne by the outer surface portion 22ha. As a result, it is possible to prevent a decrease in strength due to stress concentration on the defective portion 22a. In particular, since the defective portion 22a is formed within the range corresponding to the hollow portion 21 in the groove bottom 25a in the groove portion 25, stress concentration on the defective portion 22a can be reliably prevented. These effects are particularly effective when bending deformation due to tensile stress occurs on the grooved surface of the extruded cement plate.

As described above, the outer surface portion 22ha of the extruded cement plate 22 is the portion that produces the maximum stress level. When the ratio of the groove 25 in the surface portion 22h is increased, the cross-sectional coefficient value becomes small, and the superiority to the extruded cement plate without the groove is reduced. Therefore, of the total width W of the extruded cement plate 22, the following formula is satisfied when the width of the outer surface portion 22ha excluding the groove portion 25 is W1 and the width of the groove portion 25 is W2.
W1> W2
The width W1 of the outer surface portion 22ha excluding the groove portion 25 is the total width of the portions divided into a plurality of portions by the groove portion 25 as shown in FIG. The groove width W2 is the total width of all the groove portions, and in the case of the present embodiment, it is the total width of the two groove portions 25.

It has been found that the difference in stress between the outer surface portion 22ha of the extruded cement plate 22 and the groove bottom 25a corresponds to the ratio of the distance of the extruded cement plate 22 from the centroid N. The relationship of stress degree is (distance from the center of gravity N to the groove bottom) / (distance from the center of gravity N to the outer surface) = (bending stress degree generated at the groove bottom) / (bending stress generated at the outer surface portion). Degree). Therefore, the degree of bending stress of the extruded cement plate 22 can be calculated based on the cross-sectional shape of the extruded cement plate 22, its dimensions, and the center of gravity N.

The following equation is satisfied when the distance from the center of gravity N of the extruded cement plate 22 to the groove bottom 25a is A and the distance from the center of gravity N to the outer surface 22g is B.
A / B = 0.4 to 0.7
A / B = about 0.7 is a boundary point for avoiding stress concentration on the defective portion 22a, and by setting A / B = 0.4 to 0.7, stress concentration on the defective portion 22a is a factor. It is possible to surely prevent the decrease in strength.

When a defect portion is formed on a conventional extruded cement plate by tapping screws or the like, the strength is reduced by about 30% due to stress concentration on the defect portion, but in the groove portion 25 where the stress is 30% or more smaller than that of the surface portion 22h. By forming the defective portion 22a, it is possible to prevent the extruded cement plate 22 from being destroyed due to the influence of stress concentration.

If the exterior member mounting structure 20 of the extruded cement plate of the present embodiment is adopted, a plurality of groove portions 25 extending substantially linearly along the hollow portion 21 are formed on the surface portion 22h of the extruded cement plate 22 to finish. Since the defective portion 22a is formed within the range corresponding to the hollow portion 21 in the groove bottom 25a in the groove portion 25 for attaching the material 23, the strength does not decrease due to the stress concentration on the defective portion 22a. Therefore, the extruded cement plate 22 can be designed without lowering the allowable stress, and a high yield strength can be maintained. As a result, it is not necessary to reduce the support span of the extruded cement plate 22, and the degree of freedom in construction of the extruded cement plate 22 can be maintained.

Since the thickness S2 of the extruded cement plate 22 corresponding to the groove 25 is 40 to 100 mm, the high strength of the extruded cement plate 22 can be maintained. Of the total width W of the extruded cement plate 22, the width W1 of the outer surface portion 22ha excluding the plurality of groove portions 25 exceeds the width W2 of the plurality of groove portions 25, which is superior to the extruded cement plate having no groove portion. Can be kept.

The distance A from the center of gravity N of the extruded cement plate 22 to the groove bottom 25a and the distance B from the center of gravity N to the outer surface 22g satisfy A / B = 0.4 to 0.7, and thus are defective. It is possible to reliably prevent a decrease in strength due to stress concentration on the portion 22a.

Conventionally, in order to increase the support span of the extruded cement plate, the thickness of the extruded cement plate has been increased. As a result, the cross section becomes large, and the cost increases due to the increase in the burden on the work site due to the increase in weight. Since the extruded cement plate 22 of the present embodiment maintains high strength without increasing the thickness, the weight does not increase and the cost does not increase.

FIG. 7 is a cross-sectional view and a front view showing an exterior member mounting structure 30 of an extruded cement plate according to a second embodiment of the present invention. The groove 32 of the extruded cement plate 31 of the present embodiment is formed to be wide. The signboard 33, which is an exterior member, is fixed in the groove 32 of the extruded cement plate 31 by a mounting means 35 composed of a plurality of mounting bolts 34 and the like. A plurality of defective portions 31a, which are bolt holes of the mounting bolts 34, are formed in the groove bottom 32a of the groove portion 32. The defective portion 31a is formed within a range corresponding to the hollow portion in the groove bottom 32a in the groove portion 32.

Even when the signboard 33, which is an exterior member, is attached in the groove 32, the defective portion 31a is formed in the groove 32, and the position of the defective portion 31a is within the range corresponding to the hollow portion in the groove bottom 32a in the groove 32. By setting the value to the inside, the strength does not decrease due to the stress concentration on the defective portion 31a. Therefore, the extruded cement plate 31 can be designed without lowering the allowable stress, and a high yield strength can be maintained. As a result, it is not necessary to reduce the support span of the extruded cement plate 31, and the degree of freedom in construction of the extruded cement plate 31 can be maintained.

The present invention is not limited to the respective embodiments and examples. These embodiments and examples are examples of the extruded cement plate according to the present invention and the exterior member mounting structure of the extruded cement plate, and are not limited. The extruded cement board according to the present invention and the structure for mounting the extruded cement board to the skeleton to which the exterior member mounting structure of the extruded cement board is applied are not limited. The number and shape of the grooves, the number and shape of the through holes, the shape of the defective portion by the mounting means, and the like are not limited. The type of exterior member is not limited, and for example, the exterior member may be used as a wall surface decoration material. The above embodiments may be used in combination. Various members provided as needed, such as square nuts and clips for attaching the extruded cement plate, may have any form as long as the effects of the present invention are not impaired.

1, 10, 15 Extruded cement board 1h Surface part 1ha Outer surface part 1g Outer surface 2, 21 Hollow part 3 Partition wall 4, 17 Through hole 5, 16 Groove part 5a Groove bottom 5b Side end 6 Inclined part 11 First groove part 12th 2 Grooves 20, 30 Extruded cement board exterior member mounting structure 22, 31 Extruded cement board 22h Surface part 22ha Outer surface part 22g Outer surface 22a Missing part 23 Finishing material 24, 35 Mounting means 25, 32 Groove 25a Groove bottom 25b Side end 26 Tapping screw 27 Falling prevention iron wire 33 Sign 34 Mounting bolt 40 Conventional extruded cement plate 41 Through hole D Through hole diameter Wm Groove bottom width W Overall width W1 Outer surface width W2 Groove bottom width S1 Extruded cement Plate thickness S2 Thickness of extruded cement plate corresponding to the groove N Center A Distance from the center to the bottom of the groove B Distance from the center to the outer surface K Load

Claims (5)

In an extruded cement board in which a plurality of hollow portions are arranged side by side in one direction and have through holes for passing equipment or pipes penetrating the front and back surfaces.
A single groove portion extending substantially linearly along the hollow portion is formed on the surface portion, and the through hole is formed in the groove portion .
Both ends of the groove are inclined inward toward the bottom of the groove, and the groove is formed in an inverted trapezoidal shape in cross section.
The groove portion is formed so as to overlap a plurality of hollow portions in the thickness direction of the extruded cement plate and to exceed two adjacent hollow portions of the overlapping hollow portions in the width direction of the extruded cement plate. Extruded cement board as a feature. The extruded cement plate according to claim 1, wherein the extruded cement plate corresponding to the groove has a thickness of 40 to 100 mm. The extruded cement according to claim 1 or 2, wherein of the total width of the extruded cement plate, the width excluding the groove is W1, and the width of the groove is W2, the following formula is satisfied. Board.
W1> W2 Claim 1 is characterized in that the following formula is satisfied when the distance from the centroid of the extruded cement plate to the groove bottom of the groove is A and the distance from the centroid to the surface of the extruded cement plate is B. 3. The extruded cement board according to any one of 3.
A / B = 0.4 to 0.7 The extruded cement plate according to any one of claims 1 to 4, wherein the groove is formed on both the front side and the back side of the extruded cement plate.

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