JP3448020B2 - Double bottom structure - Google Patents

Description

Description: 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 partition in a cargo area of a ship. 2. Description of the Prior Art Conventionally, as shown in FIGS. 4, 5 and 6, an outer shell of a double bottom 30 is constituted by a bottom plate 31 and an inner bottom plate 32. The internal structure is such that one to three girder plates 33 in 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 firmer when it is formed in a lattice shape with a girder and a physical rib. In consideration of the structure of the swash plate and the like continuous through the inner bottom plate, only the rigidity of the girder plate is good, and if it does not follow the deformation of the swash plate or the like, the stress of the inner bottom plate of the girder plate portion increases, There was a problem that the high stress in the portion became stress concentration, exceeded the fracture value, and caused cracking. 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, the actual ribs are provided in the frame space of 3 to 5 intervals, and the swash plate of the lower stool and the foot of the front wall are connected only through the inner bottom plate. By providing this, 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 relates to a double bottom structure having an inner bottom plate and a ship bottom outer plate. The ribs are welded to the inner bottom plate, the longitudinal ribs of the bottom are welded to the bottom outer plate, and three to five physical ribs are provided laterally in a predetermined frame space. The bottom plate is connected with the outer bottom plate, inner bottom plate, body rib, inner bottom longitudinal rib, and bottom longitudinal rib, and the swash plate of the lower stool and
The foot of the front wall is through the inner bottom plate,
Are located on the actual ribs and are welded to the inner bottom plate.
It is . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention does not provide a girder plate in the longitudinal direction, but uses an inner bottom longitudinal rib and a ship bottom longitudinal rib for each longitudinal space. A substantial rib is provided in the frame space, the swash plate of the lower stool and the foot of the front wall are connected to the substantial rib through the inner bottom plate, and the rib is only crossed by the longitudinal rib. The structure is such that the rigidity is equal and the stress distribution is uniform. 1, 2 and 3, the double bottom 30 has an outer shell composed of a hull outer plate 1 and an inner bottom plate 2, and the internal structure is as follows. In the longitudinal direction, the inner bottom longitudinal ribs 5 are welded to the inner bottom plate 2 for each longitudinal space, the bottom longitudinal ribs 6 are welded to the bottom outer plate 1, and one to three out of three predetermined frame spaces in the lateral direction. By the physical rib 4 of the place,
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 passes through the inner bottom longitudinal rib 5 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. 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 longitudinal direction of the hull. 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. Since the present invention is configured as described above, it has the following effects. 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 only vertical ribs having the same rigidity as the actual rib plate, so that the stress distribution becomes uniform and the swash plate and inner bottom plate are welded. It is intended to prevent cracks at the ends.
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. [Description of Signs] 1 Bottom outer plate 2 Inner bottom plate 3 Bracket 4, 49 Body rib plate 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 Reference Signs List 10 Human hole 11 Diaphragm 12 Stiffener 30 Double bottom

Claims (1)

(57) [Claims 1] In a double bottom structure having an inner bottom plate and a bottom outer plate, longitudinally extending inner bottom ribs are welded to the inner bottom plate for each longitudinal space, and Through ribs are welded to the bottom shell of the ship, and three to five physical ribs are provided in a predetermined frame space in the lateral direction, and the bottom shell and the inner shell are connected only by the body ribs. , Slab of lower stool and
The foot of the front wall is through the inner bottom plate,
The double bottom structure, which is located on each of the actual ribs and is welded to the inner bottom plate .