JP4172896B2 - Tank roof construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tank roof construction method.
[0002]
[Prior art]
When constructing an underground cryogenic tank that stores low-temperature liquefied gas such as LNG (liquefied natural gas), the underground space is formed by digging the ground, and has a bottom portion and a side wall portion in the underground space. After constructing the tank body with reinforced concrete structure, assemble a dome-shaped steel roof at the bottom of the tank body, then introduce pressurized air between the steel roof and the bottom of the tank body by air pressure An air-raising method is employed in which a steel roof is levitated and the steel roof is connected to the upper end of the side wall of the tank body.
[0003]
In such an underground cryogenic tank, a steel roof is levitated by air pressure and connected to the upper end of the side wall of the tank body, and then concrete is placed on the upper surface of the steel roof with reinforcing bars and PC steel wires. However, in the case of a steel roof that constitutes a component of such a concrete roof part, in general, a concrete roof part is provided. As there is not enough rigidity at the stage before being completed, and it is formed in a dome shape with a relatively high flatness, it is difficult to make the steel roof self-supporting when assembling at the bottom of the tank body, It must be assembled while supporting it from below with many supporters.
[0004]
[Problems to be solved by the invention]
However, in the conventional method as described above, before the steel roof is lifted by air pressure, an operation of laying a cold insulation material or a membrane on the lower surface of the steel roof using an aerial work vehicle or the like must be performed. However, since many support works are erected under the steel roof, there is a problem that it is difficult to perform the work of laying the cold insulation material and the membrane because these support works become an obstacle.
[0005]
The present invention has been made in view of the above-described circumstances. In constructing a dome-shaped roof having low rigidity and high flatness, it is difficult to stand on its own. The object is to make it possible to easily perform the laying operation on the lower surface.
[0006]
[Means for Solving the Problems]
In the present invention, a dome-shaped roof having low rigidity and high flatness, which is difficult to stand independently, is assembled while being supported by a number of supporters at the bottom of the tank body, and then the tank body is provided with a plurality of wires interposing tension adjusting means. The appropriate position of the roof is suspended and supported from the side wall portion of the roof, and the suspension support is performed while monitoring the tension applied to each wire and adjusting so that the tension is always maintained, and then, subjected to laying work on the roof underside by removing the支保Engineering supporting the roof, each of said wire and removed while supporting the roof pneumatically by introducing pressurized air between the bottom of the roof and the tank body Then, the construction method of the tank roof is characterized in that the roof is raised by air pressure by introducing further pressurized air and fixed to the upper end of the side wall of the tank body.
[0007]
In this way, it is possible to suspend and support the appropriate position of the roof via a wire from the side wall portion of the tank body, and to remove the support work supporting the roof. By utilizing the secured wide work space, it is possible to easily perform the laying work on the lower surface of the roof.
[0008]
Further, in the present invention, the roof is suspended and supported by a plurality of wires having tension adjusting means interposed therebetween, and the tension applied to the wires is monitored by the suspension support so that the tension is always kept even. Since adjustment is performed while the wire expands or contracts due to changes in the outside air temperature, the roof is stably controlled by controlling the displacement of the roof by monitoring the tension of the wire. It becomes possible to make it.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
1 to 6 show an example of an embodiment for carrying out the present invention. As shown in FIG. 1, in constructing an underground cryogenic tank, a bottom 2 is constructed in an underground space 1 in which the ground is dug, The tank body 4 is constructed by sequentially constructing the side wall 3 upward from the periphery of the bottom 2, and the construction of the dome-shaped roof 5 at the bottom 2 after the construction of the bottom 2 is completed. To start.
[0011]
Here, since the dome-shaped roof 5 in the illustrated example has a low rigidity and a high flatness, it is difficult to stand on its own. Therefore, a bracket 7 having a temporary frame 6 at the center and a temporary wall 7 at the peripheral edge. In addition, the center portion and the peripheral portion are supported by a number of supporters 8 from below and assembled. An annular walkway 9 is attached to the lower surface of the peripheral edge of the roof 5 so that the peripheral edge of the roof 5 can be supported by the walkway 9 as the assembly of the roof 5 proceeds.
[0012]
Thus, at the stage of assembling the roof 5 and entering the inner surface construction of the roof 5, the brackets 10 are temporarily installed at a plurality of locations in the circumferential direction at an appropriate height of the side wall 3, and the radial direction on the upper surface of the roof 5 that has been assembled. The brackets 11 are temporarily installed corresponding to the brackets 10 at a plurality of locations.
[0013]
Here, since the roof bone 12 is joined to the upper surface of the roof 5 in the radial direction and the circumferential direction as shown in FIG. 3, the bracket 11 is temporarily mounted by using the roof bone 12.
[0014]
Then, both ends of the wire 15 interposing the tension adjusting means 13 such as a turnbuckle and the tensiometer 14 are locked to the brackets 10 and 11, the wire 15 is stretched between the brackets 10 and 11, and the tension adjusting means. The roof 5 is suspended and supported from above by a plurality of wires 15 interposing 13 and a tensiometer 14.
[0015]
At this time, each tension meter 14 is monitored and the tension adjusting means 13 such as a turnbuckle is adjusted so that the tension is uniformly applied to the plurality of wires 15.
[0016]
After suspending and supporting the roof 5 from above with the wire 15, the supporting work 8 disposed below the roof 5 is removed as shown in FIG. 4 to secure a wide working space 16 below the roof 5. Then, an unillustrated work vehicle (not shown) is carried into the work space 16 and the cold insulation material 17 and the membrane 18 are laid on the lower surface of the roof 5 supported by being suspended from above by the wires 15.
[0017]
On the other hand, the construction of the side wall 3 has progressed during this time, and as shown in FIG. 5, the side wall 3 is built up to the top, and the construction of the tank body 4 is completed. The ring plate 19 is attached.
[0018]
Therefore, the upper ends of a plurality of other wires 20 are newly engaged with the ring plate 19 and suspended, and the lower ends of the wires 20 are coupled to the bracket 11 by interposing tension adjusting means 13 such as a turnbuckle and a tension meter 14. Then, another plurality of wires 20 with tension adjusting means 13 and tension meter 14 interposed between the ring plate 19 and the bracket 11 are stretched, and the roof 5 is suspended and supported by the plurality of wires 20 from above. Then, the wire 15 that has been supported by suspending the roof 5 is removed.
[0019]
Subsequently, the temporary brackets 7 and 10 are removed, and the seal material 21 is attached to the lower surface of the peripheral edge of the roof 5 so as to be in contact with the inner wall surface of the side wall portion 3. Even after the roof 5 is suspended and supported from above, each tension meter 14 interposed in the wire 20 is monitored to adjust the tension adjusting means 13 such as a turnbuckle so that the tension is uniformly applied to the plurality of wires 20. To.
[0020]
After the laying of the cold insulation material 17 and the membrane 18 on the lower surface of the roof 5 is completed as described above, the temporary brackets 7 and 10 are removed, and the seal material 21 is attached to the lower surface of the peripheral edge of the roof 5. Then, pressurized air is introduced between the roof 5 suspended and supported and the bottom 2 of the tank body 4, and the roof 5 is raised by air pressure as shown in FIG.
[0021]
At this time, since the temporary brackets 7 and 10 are removed, the sealing material 21 rises together with the roof 5 while maintaining a state of being in close contact with the inner wall surface of the side wall portion 3. And pressurized air does not leak from between the inner wall surface of the side wall 3.
[0022]
And, when the roof 5 is grounded by air pressure, the wire 20 is removed, and after raising the roof 5 to the uppermost part of the tank body 4, the upper surface side of the peripheral edge of the roof 5 is fastened to the ring plate 19, After arranging reinforcing bars and PC steel wires on the upper surface of the roof 5, a concrete roof is formed by placing concrete while supporting the roof 5 with air pressure to give prestress, and the introduction of pressurized air is stopped and the sealing material 21 Then, the gantry 6 is removed.
[0023]
Therefore, according to the above embodiment, the roof 5 can be suspended and supported by the wires 15 and 20 from above, and the supporting work 8 disposed under the roof 5 can be removed. Laying work of the cold insulating material 17 and the membrane 18 on the lower surface of the roof 5 can be performed very easily using the secured large work space 16.
[0024]
Since the wires 15 and 20 are provided with tension adjusting means 13 such as a turnbuckle and a tension meter 14, the tension adjusting means 13 monitors the tension of the wires 15 and 20 to a predetermined value. If the wires 15 and 20 expand and contract due to changes in the outside air temperature, the displacement of the roof 5 can be controlled and the roof 5 is suspended from above in a stable state. Can be supported down.
[0025]
In addition, the construction method of the tank roof of the present invention is not limited to the above-described illustrated examples, and it is needless to say that various modifications can be made without departing from the gist of the present invention.
[0026]
【The invention's effect】
According to the tank roof construction method of the present invention described above, the following various excellent effects can be obtained.
[0027]
(I) In constructing a dome-shaped roof with low rigidity and high flatness, it is possible to suspend and support the roof from above with a wire and to remove the support work placed under the roof. In addition, it is possible to carry out the laying work of the cold insulation material, the membrane, etc. on the lower surface of the roof by using the wide work space secured by removing the support work.
[0028]
(II) The roof is suspended and supported by a plurality of wires with tension adjusting means interposed therebetween, and the suspension support is performed while monitoring the tension applied to each wire and adjusting the tension so that it is always held evenly. Therefore, even if the wire expands or contracts due to a change in the outside air temperature, the roof can be stably supported by controlling the displacement of the roof by monitoring the tension of the wire. .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of an embodiment of the present invention.
2 is a longitudinal sectional view showing a state in which the roof of FIG.
FIG. 3 is an enlarged view showing an example of tension adjusting means.
4 is a longitudinal sectional view showing a state in which the support work of FIG. 2 is removed. FIG.
5 is a longitudinal sectional view showing a state where the wire of FIG. 4 is suspended from the ring plate. FIG.
6 is a longitudinal sectional view showing a state in which the roof of FIG. 5 is lifted by air pressure and fixed to the uppermost portion of the tank body.
[Explanation of symbols]
3 Side wall 4 Tank body 5 Roof 8 Supporting work 13 Tension adjusting means 15, 20 Wire

Claims (1)

After assembling a dome-shaped roof with low rigidity and high flatness that is difficult to stand by supporting a large number of supporters at the bottom of the tank body, it is separated from the side wall of the tank body by a plurality of wires interposing tension adjusting means. An appropriate position of the roof is supported by suspension, and the suspension support is performed by monitoring the tension applied to each wire so that the tension is always maintained evenly, and then supporting the roof. The supporting work is removed and laying work is performed on the lower surface of the roof.The air is introduced between the roof and the bottom of the tank body, and the wires are removed while supporting the roof by air pressure. The construction method of the tank roof is characterized in that the roof is raised by air pressure by introducing pressurized air and fixed to the upper end of the side wall of the tank body.

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