JP2002087374A - Double bottom structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem on a lattice structure of a double bottom itself having beam plates and actual stripe plates for more reasonable and firm construction that, in consideration of the structure of swash plates continued via inner bottom plates, only portions of the beam plates are more rigid, the stress of the inner bottom plates of the beam plate portions increase without following the deformation of the swash plates or others, and high stress of portions of the beam plates form stress concentration, exceeding a breakdown value, resulting in cracking. SOLUTION: Inner bottom vertically passing stripe ribs 5 and ship bottom vertically passing ribs 6, instead of the beam plates, are used in the longitudinal direction for every lounge and actual strip plates 4 are provided in the cross direction at three-to-five frame intervals. The roots of the swash plates 81 and front walls 82 of a lower stool 8 are located at their continuous portions on the actual stripe plates 4 via the inner bottom plates 2 and the actual stripe plates 4 have the vertically passing ribs 5, 6 only crossing each other, achieving equal rigidity and uniform stress distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double bottom structure having a lower stool of a horizontal bulkhead in a cargo area of a ship.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 4, 5, and 6, an outer shell of a double bottom 30 is constituted by a bottom outer plate 31 and an inner bottom plate 32. Is a girder plate 33 at one place in three to five of a predetermined longitudinal space in the longitudinal direction.
The outer bottom plate 31 and the inner bottom plate 32 are connected to each other, and the outer bottom plate 31 and the inner bottom plate 32 are connected to one another at three to five physical ribs 34 in a predetermined frame space in the lateral direction, thereby forming a lattice-like structure. Had.

Further, in the longitudinal direction, an inner bottom longitudinal rib 35 is welded to the inner bottom plate 32 for each longitudinal space, and a bottom longitudinal rib 36 is welded to the bottom outer plate 31 to form the double bottom 30. .

In order to partition the cargo hold back and forth, a horizontal partition 37 is provided. A lower stool 38 is provided below the horizontal partition 37, that is, on the inner bottom plate 32, as a base for the horizontal partition 37. Had been.

The lower stool 38 is formed of a trapezoidal box having a height of several meters, and has a hypotenuse 381 and a front wall 38.
The two feet were welded to the inner bottom plate 32, the upper side was provided with a top plate 383, and the horizontal partition 37 was formed on the top plate 383.

[0006] The feet of the swash plate 381 and the front wall 382 are located on the actual rib 34 and the immediately forward rib 341 via the inner bottom plate 32, respectively, and are welded to the inner bottom plate 32.

As shown in FIG. 6, a cross section of the girder plate 33 is vertically interposed. The girder plate 33 is sandwiched between the inner bottom plate 32 and the outer bottom plate 31 in the vertical direction, and the actual rib 34 is sandwiched in the horizontal direction. Was. Further, the beam plate 33 was provided with two stiffeners 39 between the actual rib plates 34 with the human hole 40 interposed therebetween.

The lower stool 38 includes a swash plate 381 and a front wall 38.
2 and a top plate 383. The feet of the swash plate 381 and the front wall 382 are connected to the actual ribs 34, 3 via the inner bottom plate 32.
41. Further, inside the lower stool 38, a diaphragm 41 is stretched, and a human hole 4 is provided.
The stiffener 42 was provided so as to surround 0. The human hole 40 is a traffic hole through which a person passes for inspection and maintenance of the double bottom 30.

As shown in the enlarged view of FIG. 6, the intersection of the inner bottom plate 32, the swash plate 381 and the actual rib plate 34 causes the inner bottom plate 32 to be deformed downward by a cargo load W such as cargo or ballast water, and The swash plate 381 bends in the vertical direction so as to fall, and the inner bottom plate 34 tends to be stretched in the vertical direction.

This will be described with reference to FIG.
81 tries to fall. The inner bottom longitudinal ribs 35 and the actual ribs 34 follow the inner bottom plate 32, but the spar 33 is not rigidly followed. Stress is concentrated at the intersection of the so-called girder plates 33.

Therefore, as shown in the enlarged view of FIG. 6, a crack B may be generated at the weld toe of the inner bottom plate 32 having the girder plate 33 on the back surface.

[0012]

As described in the prior art, the double bottom itself is more rational and solid if it is formed in a lattice shape with a girder plate and actual ribs. Considering the structure of the swash plate continuous through, the rigidity of only the girder plate part is good, the stress of the inner bottom plate of the girder plate portion increases if it does not follow the deformation of the swash plate, etc. Has a problem that the high stress causes stress concentration, exceeds the fracture value, and causes a crack.

The present invention has been made in view of the above-mentioned inadequacy of the prior art, and an object of the present invention is to use longitudinal ribs for each longitudinal space in the longitudinal direction, In the direction, by providing the actual ribs in the frame space of 3 to 5 intervals, the swash plate of the lower stool and the foot of the front wall through the inner bottom plate are provided with the actual ribs and the vertical ribs, The rigidity becomes equal, the stress distribution becomes uniform, and cracks at the weld toe of the swash plate and the inner bottom plate are prevented.

[0014]

In order to achieve the above object, the present invention provides a double bottom structure in which longitudinal ribs are welded to an inner bottom plate in longitudinal directions for each longitudinal space. The ribs are welded to the bottom shell of the ship, and the bottom shell 1 and the inner bottom plate 2 are connected to each other by three or five physical ribs in a predetermined frame space in the horizontal direction, and are composed of the vertical ribs and the vertical ribs. Is what you do.

The feet of the swash plate and the front wall are via an inner bottom plate,
It is located on the physical rib plate and the one before it, respectively, and is welded to the inner bottom plate. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention does not provide a girder plate in the longitudinal direction, uses an inner bottom longitudinal rib and a ship bottom longitudinal rib for each longitudinal space, and provides a frame space at three to five intervals in the lateral direction. The swash plate of the lower stool and the foot of the front wall are located at the part where the continuation of the lower stool is continuous with the inner bottom plate, and the part of the stool has a structure in which only vertical ribs intersect. , The rigidity is equal, and the stress distribution is uniform.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1, 2 and 3, the double bottom 30 has an outer shell composed of a hull outer panel 1 and an inner bottom panel 2, and the internal structure is vertical. In each longitudinal space, an inner bottom longitudinal rib 5 is welded to the inner bottom plate 2, a bottom longitudinal rib 6 is welded to the bottom outer plate 1, and one to three to five entities of a predetermined frame space are laterally disposed. With rib 4
The outer bottom plate 1 and the inner bottom plate 2 are connected to each other, and are composed of a body rib and a longitudinal rib.

To partition the cargo hold back and forth, a horizontal partition 7 is provided. The lower part of the horizontal partition 7, that is, the so-called inner bottom plate 2 is provided.
Above, a lower stool 8 is provided as a base for the horizontal partition 7.

The lower stool 8 is formed of a trapezoidal box having a height of several meters. The feet of the swash plate 81 and the front wall 82 are welded to the inner bottom plate 2, and a top plate 83 is provided on the upper side.
The horizontal partition 7 is formed on the top plate 83.

The feet of the swash plate 81 and the front wall 82 are located on the actual rib plate 4 and the immediately preceding actual rib plate 49 via the inner bottom plate 2, respectively, and are welded to the inner bottom plate 2.

As shown in FIG. 3, the cross section of the longitudinal ribs 5, 6 extends longitudinally, the inner bottom longitudinal ribs 5 are provided on the back surface of the inner bottom plate 2 for each longitudinal space. A vertical rib 6 is provided on the inner side, and the actual rib 4 is sandwiched between the inner bottom plate 2 and the bottom outer plate 1 in the horizontal direction. In addition, physical rib 4
The stiffener 9 and the bracket 3 are reinforced.

The lower stool 8 is composed of a swash plate 81, a front wall 82 and a top plate 83, and the feet of the swash plate 81 and the front wall 82 are located on the actual ribs 4 and 49 via the inner bottom plate 2. Further, inside the lower stool 8, one or more diaphragms 11 are provided at three to five long spaces, and a stiffener 12 is provided so as to surround the human hole 10.

At the intersection of the inner bottom plate 2, the swash plate 81, and the actual rib 4, the inner bottom plate 2 is deformed downward by the cargo load W such as cargo or ballast water, and the swash plate 81 falls down in the hull length direction. And the inner bottom plate 4 tends to be stretched in the vertical direction.

This will be described with reference to FIG.
1 tries to fall. The inner bottom longitudinal ribs 5 and the actual ribs 4 follow the inner bottom plate 2 and the stress is uniformly distributed.

[0025]

Since the present invention is configured as described above, the following effects can be obtained. The present invention uses a longitudinal rib for each longitudinal space in the longitudinal direction, and provides a substantial rib in a frame space at an interval of 3 to 5 in the lateral direction,
The swash plate of the lower stool and the foot of the front wall that are continuous via the inner bottom plate are provided with a real rib and a longitudinal rib, so that rigidity is equalized, stress distribution is uniform, and welding of the swash plate and the inner bottom plate It is intended to prevent cracks at the toe. In addition, only a vertical rib is provided vertically without a girder plate, and when performing inspection and maintenance, it is intended to facilitate movement in the horizontal direction and to improve traffic in the double bottom.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a double bottom structure according to the present invention.

FIG. 2 is a schematic plan view mainly showing an inner bottom plate of the present invention.

FIG. 3 is a schematic side view mainly showing a double bottom structure according to the present invention.

FIG. 4 is a perspective view schematically showing a conventional double bottom structure.

FIG. 5 is a plan view schematically showing a conventional inner bottom plate as a center.

FIG. 6 is a side view schematically showing a conventional double bottom structure. Also, the intersection of the inner bottom plate and the swash plate is schematically shown in an enlarged view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer bottom board 2 Inner bottom board 3 Bracket 4,49 Body rib board 5 Inner bottom vertical rib 6 Ship bottom vertical rib 7 Horizontal partition 8 Stool 81 Swash plate 82 Front wall 83 Top plate 9 Stiffener 10 Person hole 11 Diaphragm 12 stiffener 30 double bottom

Claims (2)

[Claims] In the double-bottom structure, an inner bottom longitudinal rib is welded to an inner bottom plate for each longitudinal space in a longitudinal direction, a bottom longitudinal rib is welded to a bottom outer plate, and a predetermined frame space extends in a lateral direction. A double bottom structure wherein the outer bottom plate 1 and the inner bottom plate 2 are connected to each other by one of three to five actual ribs, and are composed of the ribs and the longitudinal ribs. 2. The double bottom according to claim 1, wherein the feet of the swash plate and the front wall are respectively located on the physical rib plate and the immediately preceding physical rib plate via the inner bottom plate, and are welded to the inner bottom plate. Construction.