KR100904634B1 - Deck plate that the fulcrum of bottom surface of upper plate is moved inboard - Google Patents

Abstract

A deck plate in which the fulcrum of a bottom surface of an upper plate is provided to minimize elements which are added to existing element or are transformed and minimize the deformation of the deck plate in a longitudinal direction and a width direction. A deck plate in which the fulcrum of a bottom surface of an upper plate comprises: an upper plate(110) in which a plurality of C-shaped unit members(112) having a rib(114) are coupled to each other to be parallel and which forms the floor side of a road; and a pair of side plates(120) being formed in a longitudinal direction of the upper plate and supporting one among a plurality of ribs positioned inside the upper plate. The side plate comprises: a vertical portion(122) which is formed upward and downward and supports the upper plate; and a horizontal portion(124) which is curve-cut to be extended from the lower end of vertical portion in a horizontal direction.

Description

Deck Plate That The Fulcrum of Bottom Surface of Upper Plate is Moved Inboard}

The present invention relates to a perforated plate, and more particularly, by installing the side plate supporting the lower side of the upper plate to support a point located inward from the side end of the upper plate, it is possible to minimize deformation such as deflection due to external force, By installing side panels and bulkheads that can support other points on the bottom of the top plate inside and outside, multi-points can be provided to distribute the load on the top plate, and the load strength is excellent and the durability can be significantly increased. It is about a perforated plate.

In general, the duplex plate is used to cover the road to make traffic more smooth when digging roads for underground facilities such as subway construction.

As shown in FIG. 1, the perforated plate 10 is formed in a shape having a flat surface for a vehicle to pass through, and a plurality of support beams 8 supporting a construction zone formed for construction of an underground facility. Dozens or hundreds of perforated plates 10 are arranged on the upper side to form a temporary road surface, and the vehicle passes over them.

As shown in FIG. 2 and FIG. 3, the above-described perforated plate includes an upper plate 12, a side plate 14, and a partition wall 16.

The top plate 12 is welded in parallel with the unit member 13 having a cross-section of the "c" shape, the top surface is formed flat so that the car can pass.

In addition, the top plate 12 is coupled to each other in a state in which the opening of the unit member 13 having a cross-section of the "c" shape is located downward, thereby protruding along the bottom surface of the top plate. Ribs are formed.

The side plate 14 is coupled to both ends of the top plate 12 to support both ends of the top plate 12.

The side plate 14 as described above is bent in the form of "b" is the bottom is coupled to the support beam 8 of the construction zone.

In addition, a bottom wall of the upper plate 12 is provided with a partition wall 16 at predetermined intervals in the longitudinal direction of the upper plate 12.

The partition wall 16 supports the bottom surface of the upper plate 12 to the side plate 14 at predetermined intervals.

When the width of the perforated plate 10 is a and the length is b, the deformation (I) in the width direction of the perforated plate 10 is formed in the form of forming an arc downward.

On the other hand, the deformation (II) in the longitudinal direction of the perforated plate 10 is in the form of an arc downwards, the portion supported by the partition wall 16 is made of a discontinuous shape.

However, the conventional perforated plate 10 as described above has the following problems.

Assuming that the load w acts on the perforated plate 10, the perforated plate 10 has a maximum deformation at an intermediate point in the width direction, and the deformation amount δa is as follows.

Here, α is a coefficient when the load is a concentrated load, and β is a coefficient when the load is a distributed load. In addition, E is the elastic modulus, I is the secondary cross-sectional moment value.

On the other hand, the perforated plate 10 is deformed in the longitudinal direction as shown in (II), the deformation in the longitudinal direction of the perforated plate 10 in addition to the deformation caused by the load for the width direction of the perforated plate 10 The additional deformation amount due to the Poisson's ratio of the deformation amount δa is added.

That is, the deformation amount along the longitudinal direction of the porous plate 10 is additionally generated by a Poisson's ratio corresponding to the material characteristic value of the second hole plate 10 by the deformation amount along the width direction of the second hole plate 10.

Therefore, the larger the deformation amount δa along the width direction of the birefringent plate 10, the greater the deformation amount in the longitudinal direction of the birefringent plate 10, which makes the durability of the perforated plate 10 weaker. Efforts have been made to minimize the amount of deformation (δa) in the width direction of.

In addition, each unit member, side plate 14, partition 16, etc. of the conventional perforated plate 10 are all welded together, but the side plate 14 is bent in a "b" shape, and the side plate 14 The horizontally extending bottom surface of) is directed toward the center side of the perforated plate 10, so that the welding space is narrow when welding the partition 16, which may cause deterioration of workability and poor welding quality.

In addition, a plurality of slits 18 into which ribs extending downward from the bottom of the upper plate are inserted are formed at an upper end of the partition wall 16.

In addition, as described above, the bottom surface of the side plate 14 faces inwards, and when the perforated plate 10 is assembled, the partition wall 16 must be joined before the side plate 14, and the side plate 14 must be coupled as described above. The process must be followed in order to produce a problem that the manufacturing process is not easy.

In addition, in the prior art, a variety of perforated plates have been proposed, but each structure is unique, and therefore, there is a problem in that a large-scale facility line is additionally needed because new structures must be newly manufactured without using a structure widely used in the related art.

In addition, since the side plate 14 is coupled to both ends of the upper plate 12 in the case of the conventional double hole plate 10, the load applied from the upper portion of the upper plate (10) is concentrated on both ends of the upper plate 12 when used for a long time The problem that the connection part of the both ends of the 12 and the side plate 14 generate | occur | produces is broken, and the problem that durability falls remarkably arises.

The present invention is to solve the above problems, an object of the present invention is to minimize the components to be added or deformed in the conventional components, and at the same time minimize the amount of deformation in the width direction of the perforated plate length of the perforated plate It is to provide a perforated plate that can minimize the amount of deformation in the direction.

In addition, by forming a plurality of ribs on the bottom surface by mutually combining the unit panels of the "C" shape in parallel to the top plate by providing a multi-support point to support the side plate, barrier ribs, side panels and inner panels on the plurality of ribs To provide a perforated plate to distribute the load applied, excellent load strength, and durability can be significantly increased.

According to one aspect of the present invention for achieving the above object, the "c" shaped unit member having a rib extending downward from both ends is made of a plurality of mutually coupled in parallel, the bottom surface of the road It is formed along the longitudinal direction of the upper plate and the upper plate, and the upper end portion comprises a pair of side plates each supporting at least one of the ribs of the plurality of ribs located inward from both side ends of the upper plate, characterized in that do.

In addition, the side plate is formed to extend to the lower side of the upper plate, the upper end extending from the lower end of the vertical portion and the vertical portion for supporting at least one of the ribs of the plurality of ribs located inward from both side ends of the upper plate, respectively It may comprise a horizontal portion.

In addition, it is preferable to further include a partition wall provided in the width direction of the top plate between the pair of side plates of the bottom of the top plate.

In addition, the partition wall may be provided in a plurality of spaced apart from each other in the longitudinal direction of the top plate.

In addition, the partition wall is preferably formed with a slit in which the end of the rib is inserted in a position corresponding to the plurality of ribs.

In addition, the upper plate may include a pair of side panels formed along a longitudinal direction of the upper plate, one end of each of which is supported at both ends of the upper plate, and the other end of the pair of side plates, respectively.

In addition, the upper panel may further include an inner panel formed along a longitudinal direction of the upper plate, one end of which is supported by at least one rib among a plurality of ribs positioned between the pair of side plates, and the other end of which is supported on one side of the side plate. have.

Here, the inner panel is preferably a plurality of spaced apart from each other along the longitudinal direction of the top plate.

First, since the deformation in the widthwise direction of the perforated plate is minimized, the longitudinal deformation of the perforated plate is minimized by the Poisson's ratio, thereby increasing the durability of the perforated plate.

Second, the upper panel is formed by forming a plurality of ribs on the bottom surface by mutually combining the "c" shaped unit panels in parallel to provide multiple support points to support the side plates, partition walls, side panels and inner panels on the plurality of ribs. There is an effect to disperse the load applied, excellent load strength, and significantly increased durability.

Third, even if less material is used for the perforated plate, the same strength as in the prior art can be maintained, thereby reducing the weight of the perforated plate, and the load on the structures such as the support beams supporting the perforated plate is also reduced, thereby reducing the overall weight. There is a saving effect.

Fourth, since the configuration of the present invention is possible only by changing the installation position of the conventional side plate can make the most of the conventional perforated plate components can be utilized to minimize the production of additional additional components can also reduce the production cost, in the field There is an effect that can be applied immediately.

Fifth, the joining surface of the side plate, the top plate and the partition wall is more open to the outside than the conventional one, the space of the joining work is vast, which is expected to improve the workability of the joining work and prevent the deterioration of the joining quality. Can be.

Sixth, since the side plate and the partition wall can be installed without affecting each other independently, the work process can be more flexible, thereby improving workability at the work site.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the description of this embodiment, the same name and the same reference numerals are used for the same configuration and additional description thereof will be omitted.

The perforated plate according to the exemplary embodiment of the present invention may include the upper plate 110 and the side plate 120 as shown in FIGS. 4 and 5.

The upper plate 110 is formed by coupling a plurality of “c” shaped unit members 112 having ribs 114 extending downward from both side ends thereof in parallel. That is, the unit member 112 of the "c" shape is formed by the ribs 114 extending downward from both side ends to form a flat upper surface to form the bottom surface of the road through which the vehicle can pass, the bottom is a plurality of ribs It is a structure in which strength is reinforced by 114.

The rib 114 is formed perpendicular to the bottom of the upper plate 110 as described above to reinforce the shear strength of the upper plate 110 to minimize the amount of deformation that the upper plate 110 is deformed downward by the vehicle and its own weight and In addition, the side plate 120 and the partition wall 130 or the side panel 140 and the inner panel 150 to be described later in another embodiment serves to provide a plurality of support points to be accompanied.

In addition, the side plate 120 is a component for supporting the top plate 110, is formed along the longitudinal direction of the top plate 110, the side plate 120 to support both ends of the top plate 110 as in the prior art Rather, the support points on the inner side of the upper end of the upper plate 110, that is, the support points provided on the ribs 114 of the upper plate 110 to support the point located on the inner side than the both ends of the upper plate 110 This is a key feature.

Here, the position where the side plate 120 supports the top plate 110 may be to support any point on the inside from both ends of the top plate 110.

The side plate 120 may include a vertical portion 122 and a horizontal portion 124. The vertical portion 122 is formed in the vertical direction to support the upper plate 110, the horizontal portion 124 is bent to extend in the horizontal direction at the lower end of the vertical portion 122.

Here, the horizontal portion 124 of the side plate 120 is bent to the outside only a pair of side plates 120 to form a "┛┗" or extending inward and outward, respectively, such as "┻ ┻" shape It is also possible to achieve.

The side plate 120 as described above may be made to have substantially the same shape and dimensions as the conventional side plate 14. That is, it is made of the same form as the conventional one, but the structure coupled to the top plate 110 is different.

In addition, in one embodiment of the present invention, the partition wall 130 may be further provided. The partition wall 130 is a component that is installed to be spaced apart at a predetermined interval in the longitudinal direction of the upper plate 110 to support the bottom surface of the upper plate 110.

The partition wall 130 is formed in a rectangular plate shape, and is provided in the width direction of the upper plate 110 between both vertical portions 122 of the side plate 120 provided by a plurality of ribs 114 multiple support points It is installed to support.

In addition, in the present embodiment, as shown in FIG. 4, the partition wall 130 is provided every 1/4 point of the length b of the porous plate 100. However, the present invention is not limited thereto, and various modifications are possible.

Therefore, the partition wall 130 can be welded and joined after being sandwiched between the two vertical portions 122 of the side plate 120 to be joined to the side plate 120 and the joint portion to the top plate 110. It is more open to the workers, thus enlarging the joining work area, thereby improving the work convenience and improving the joining quality.

In addition, any one of the partition wall 130 or the side plate 120 may be arbitrarily combined with the upper plate 110 first, and then the other may be combined, thereby improving flexibility in the work process.

In addition, although the protrusion lengths of the ribs 114 formed on the bottom of the upper plate 110 are the same as shown in FIGS. 4 and 5 in this embodiment, as shown in FIG. 6, both side ends of the plurality of ribs 114 are shown. Of course, the rib 114 may have a protruding length smaller than that of the other ribs 114 and may be formed to have different protruding lengths by applying the same.

Hereinafter, a description will be given of the behavior that occurs when the porous plate 100 made as described above is installed in a construction zone and subjected to a load by a vehicle or the like.

Figure 7 is a perspective view of a perforated plate according to an embodiment of the present invention.

The width of the porous plate 100 is a, the length of the porous plate 100 is b as in the prior art.

The distance between the points supported by the side plate 120 is c, the distance from the support point supported by the side plate 120 to the side end of the top plate 110 is d.

In addition, the form in which the distribution load w acts on the upper plate 110 of the perforated plate 100 will be described as an example.

On the other hand, I is a curve which shows the deformation | transformation form with respect to the width direction of the conventional perforated plate, and II is a curve which shows the deformation | transformation form with respect to the longitudinal direction of the conventional perforated plate.

When the distribution load w is applied to the upper plate 110 of the perforated plate 100, the deformation form in the width direction of the perforated plate 100 of the present invention is made as III. That is, since the side plate 120 supports the bottom of the top plate 110 at a point spaced inwardly from both side ends of the top plate 110 by d, the overall deformation of the top plate 110 has a wave-like shape.

At this time, the maximum deformation in the width direction of the perforated plate 100 is generated at the center of the perforated plate 100, the size (δc) is as follows.

Here, α is a coefficient when the load is a concentrated load, and β is a coefficient when the load is a distributed load. In addition, E is the elastic modulus, I is the secondary cross-sectional moment value.

On the other hand, when both ends of the top plate 110 is supported as in the prior art, the deformation is made as I, the maximum deformation amount (δa) is as follows.

Here, E and I are the same as the numerical values for the physical properties and the cross-sectional shape, the same, the distribution load w acts the same, as shown in Figure 6 a is larger than c, the deformation amount of the top plate 110 is a Since δc is proportional to the square of the difference between and c, it can be seen that δc is significantly smaller than δa.

In addition, the deformation amount δd of the side end portion of the upper plate 110 from the side plate 120 is as follows.

Is the coefficient according to the type of load. Comparing the δd with δa, it can be seen that the length of d is much shorter than the length of a, and δd is smaller than δa.

Here, the distance d from the support point to the side end of the upper plate 110 is preferably set within a range smaller than a, and the range of d where δd is smaller than δa is apparent to those skilled in the art. Detailed description will be omitted.

In addition, a more preferable range of the distance d from the support point to the side end of the upper plate 110 is more preferably equal to or smaller than the distance c between the points supported by the side plate 120.

The reason why the value of the distance d from the support point to the side end of the upper plate 110 is formed equal to or smaller than the distance c between the points supported by the side plate 120 is greater than the value of c. In this case, the shear strength of the central portion of the upper plate 110 is remarkably improved, while the shear strength of both ends of the upper plate 110 is significantly lower than the shear strength of the central portion of the upper plate 110. Because.

Therefore, in the present embodiment, it is most preferable that the sum of the values of d of the neighboring two perforated plates is formed to be equal to the value of c in consideration of the installation of a plurality of the perforated plates, so that δd and δc of both perforated plates are balanced. .

On the other hand, the deformation form in the longitudinal direction of the perforated plate is made as IV. That is, the overall shape is similar to II, which is a deformation form with respect to the longitudinal direction of the conventional perforated plate, but II, which is a deformation form with respect to the longitudinal direction of the conventional perforated plate, is added to the width direction of the perforated plate in addition to the deformation of the perforated plate by the load w. Deformation according to the Poisson's ratio by the amount of deformation δa also occurred.

Of course, the deformation in the longitudinal direction of the present invention also occurs a deformation due to the Poisson's ratio of the deformation amount δc in the width direction of the perforated plate, but as described above, since δc is smaller than δa, It can be seen that the influence on the deformation is small.

Therefore, the maximum deformation amount in the longitudinal direction of the porous plate of the present invention is smaller than the maximum deformation amount in the longitudinal direction of the conventional porous plate.

Meanwhile, as shown in FIG. 8, the partition 130 preferably includes a plurality of slits 134 in which the ribs 114 of the upper plate are inserted into the upper side of the partition 130. It may be supported by a number of support points provided by ribs 124 without forming 134.

Meanwhile, in the above-described embodiment, both ends of the side surface of the top plate 110 are not supported free ends. According to another embodiment of the present invention, a pair of side panels 140 supporting both ends of the top plate 110 are provided. ) May be provided.

9A is a cross-sectional view of a porous plate according to another embodiment of the present invention, FIGS. 9B and 9C are cross-sectional views showing another form of the side panel of FIG. 9A, and FIG. 9D is a bottom view of the side panel of FIGS. 9A and 9C.

In the description of the present embodiment, the upper plate 110, the side plate 120 and the partition wall 130 are the same as the above-described embodiment, the same reference numerals are used, and description thereof will be omitted.

As shown in FIG. 9A, the pair of side panels 140 are formed along the longitudinal direction of the upper plate 110 in a “b” -shaped cross section, and one end portion thereof has ribs 114 positioned at both side ends of the upper plate 110. It is supported on each, and the other end is supported on one side of the pair of side plates 120, respectively.

In the present exemplary embodiment, the side panel 140 is exemplarily described as the “b” shaped plate member bent inwardly, but the shape of the side panel 140 according to the present invention is not limited thereto, and FIG. 9B. And as shown in 9c the side panel 140 is formed of a flat plate may be installed vertically or inclined from the both ends of the upper plate 110 to the end of the horizontal portion 124 described above.

In addition, in the present embodiment, as shown in FIG. 9D, the plurality of side panels 140 are spaced apart by a predetermined distance along the longitudinal direction of the upper plate 110, but this is merely an example for helping to explain the present invention. Of course, the plurality of side panels 140 may be integrally formed.

Such a side panel 140 supports the load applied to both side ends of the top plate 110 while supporting both end portions of the top plate 110 as well as a plurality of parallel plate 100 according to an embodiment of the present invention in parallel. When the dog is coupled to each other, there is an effect of reducing the deformation width along the width direction of the upper plate 110 by supporting the bottom surface of the upper plate 110 positioned between the side plates 120 of the adjacent perforated plate 100.

When the side panel 140 is installed along the longitudinal direction of the upper plate 110, loads applied to the upper plate 110 are distributed to the side plate 120 and the side panel 140, so that both side ends of the upper plate 110 may be used even for a long time. The problem that is damaged does not occur.

As a result of the structural analysis, when the load is applied to the top plate 110 in the support structure as shown in Figure 9a it was found that the load is distributed in the ratio of the side panel and the side plate in the ratio of about 3: 7.

Meanwhile, according to another embodiment of the present invention, as shown in FIG. 10, an inner panel 150 supporting the bottom surface of the upper plate 110 may be further provided between the pair of side plates 120.

The inner panel 150 has one end supporting one of the ribs 114 among the plurality of ribs 114 positioned between the pair of side plates 120, and the other end is supported on one side of the side plate 120 to allow the top plate 110 to be supported. This function distributes the load applied to) through multiple points. The inner panel 150 is provided to be inclined to be supported by the side plate 120 from any one of a plurality of points provided by the rib 114, a pair may be provided symmetrically on both sides for balance. have.

That is, as shown in FIG. 11, a pair of points supported by a pair of inner panel 150 among multiple points provided by the plurality of ribs 114 may be installed to be spaced from each other, and a pair of inner The partition wall 130 described above may be additionally installed between the panels 150 in the width direction of the upper plate 110.

In addition, as shown in FIG. 12, the inner panel 150 may be configured to simultaneously support the center portion of the upper plate 110.

In addition, as illustrated in FIG. 11, the inner panel 150 may be formed in plural along the longitudinal direction of the upper plate 110.

At this time, the plurality of inner panel 150 is preferably installed to be spaced apart a predetermined interval, the partition wall 130 described above between the plurality of inner panel 150 is installed to be spaced a predetermined interval in the longitudinal direction of the upper plate (110). This can be installed further.

In addition, as shown in FIG. 13, the partition wall 130 of the perforated plate of FIG. 9B may be omitted, and the inner panel 150 may be installed instead of the partition wall 130.

In addition, in the above-described embodiments, as the unit member 112 constituting the upper plate 110, the cross-section is a "c" shape is mentioned as an example that a plurality of coupled to each other, the present invention is not limited to this, other forms It is also possible to use the unit member 112 having a cross section of. For example, although not shown in the drawings, the unit member provided on both sides may have a unit member having a 'H' cross section, and an inner unit member having a "c" cross section may be used. Combined use and combination of unit members is possible and this is also within the scope of the present invention.

In addition, in the above-described embodiments, each of the components constituting the perforated plate may be formed of a metal material such as an iron plate, or may be formed of various materials such as made of a material such as wood.

Having looked at the preferred embodiment according to the present invention as described above, in addition to the embodiment described above, the fact that the present invention can be embodied in other specific forms without departing from the spirit or scope of the present invention having ordinary skill in the art It is obvious to them. Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive, and thus, the present invention is not limited to the above description and may be modified within the scope of the appended claims and their equivalents.

1 is a perspective view briefly showing an installation example of a conventional perforated plate;

2 is a cross-sectional view showing a cross section of a conventional perforated plate;

Figure 3 is a perspective view showing a modified form according to the load load of the conventional perforated plate;

4 is an exploded perspective view of the perforated plate of the present invention;

5 is a cross-sectional view of FIG. 4;

6 is a sectional view showing another form of the rib of the present invention;

7 is a perspective view showing a modified form according to the load load of the perforated plate of the present invention;

FIG. 8 is a front view showing another form of the partition of FIG. 4; FIG.

9A is a sectional view showing an example in which the side panel is provided in FIG. 5;

9B and 9C are sectional views showing another form of the side panel of FIG. 9A;

9D is a bottom view of the side panel of FIGS. 9A and 9C;

10 is a cross-sectional view showing another embodiment of the perforated plate of the present invention;

11 is a bottom view of FIG. 10; And,

12 is a cross-sectional view showing another example of installation of the inner panel of FIG. 10;

FIG. 13 is a sectional view showing still another example of installation of the inner panel of FIG. 12; FIG.

<Description of the symbols for the main parts of the drawings>

100: perforated plate 112: unit member

120: side plate 124: horizontal portion

134: slit 150: inner panel

110: top 114: rib

122: vertical portion 130: partition wall

140: side panel

δa: maximum deformation in the width direction of a conventional perforated plate

δb: maximum longitudinal deformation of a conventional perforated plate

δc: maximum deformation in the width direction of the perforated plate of the present invention

δd: maximum deformation of side edge of top plate from supporting point by side plate

Ⅰ: Deformation curve in the width direction of the conventional perforated plate

II: Longitudinal deformation curve of the conventional perforated plate

III: Width Deformation Curve of the Perforated Plate of the Present Invention

IV: longitudinal deformation curve of the perforated plate of the present invention

Claims (8)

A top plate formed of a plurality of “c” shaped unit members having ribs extending downward from both end portions thereof and being coupled to each other in parallel and forming a bottom surface of the road; And The upper plate lower support point is formed along the longitudinal direction of the upper plate, and the upper end includes a pair of side plates respectively supporting at least one rib among the plurality of ribs located inward from both side ends of the upper plate. Shifted perforated plate. The method of claim 1, The side plate, A vertical portion extending downward of the upper plate and having an upper end supporting at least one rib among a plurality of ribs located inward from both end portions of the upper plate; And The upper plate lower support point is moved to the inside, characterized in that it comprises a horizontal portion extending outward from the lower end of the vertical portion. The method of claim 1, The upper support plate is formed along the longitudinal direction of the upper plate, one end is respectively supported on both side end portions of the upper plate, the other end comprises a pair of side panels each supported on one side of the pair of side plates The perforated plate moved inward. The method of claim 1, An inner panel formed along the longitudinal direction of the upper plate, one end of which is supported by at least one of the plurality of ribs positioned between the pair of side plates, and the other end of which is supported by one side of the side plate; The upper plate lower support point is moved to the inside. The method of claim 4, wherein The inner panel is a plurality of perforated plate bottom support points, characterized in that the plurality of spaced apart from each other in the longitudinal direction of the upper plate is moved inward. The method of claim 1, The upper plate lower support point is moved to the inside of the bottom surface of the upper plate further comprising a partition wall installed in the width direction of the upper plate between the pair of side plates. The method of claim 6, The partition wall has a plurality of spaced apart from each other in the longitudinal direction of the upper plate, the upper support plate lower support plate moved inward. The method of claim 6, The barrier rib has a top plate lower support point is moved to the inside, characterized in that the slit is inserted into the end of the rib is formed in a position corresponding to the plurality of ribs.

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