JP2018076112A - Wind resistance reinforcement method for cylindric tank under construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind resistance reinforcing method which can rationally reinforce cylindrical tanks under construction.SOLUTION: By setting up wires from the outside of a cylindrical tank 10 on the side plate 12 of the cylindrical tank 10 under construction, it is a wind resistance reinforcing method of the cylindrical tank under construction which reinforces the cylindrical tank 10 under construction against prevailing wind. The wind resistance reinforcing method of the cylindrical tank under construction is characterized by setting up wires which do not cover the whole circumference of the side plate 12 and at the same time face the scope of prevailing wind.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wind-resistant reinforcing method for a cylindrical tank being constructed. In particular, the present invention relates to a windproof reinforcement method for a cylindrical tank in the middle of constructing a side plate of the cylindrical tank.

  Conventionally, when constructing a floating roof type cylindrical oil tank or a dome-type flat bottom cylindrical tank, the side plates are sequentially raised in a cylindrical shape to perform construction such as welding and inspection. In the cylindrical tank in the middle of construction, the side plate of the cylindrical tank has extremely low rigidity in the out-of-plane direction, and if the wind pressure is perpendicular to the side plate during strong winds, the side plate will buckle, and in the worst case, it will collapse. .

  Therefore, the cylindrical tank in the middle of construction is reinforced for strong wind measures. FIG. 6 is a diagram for explaining an example of a conventional windproof reinforcement method for a cylindrical tank in the middle of construction. FIG. 6A is a plan view thereof, and FIG. 6B is an end view of a cut portion taken along line XX of FIG. As shown in FIG. 6A, in such a conventional windproof reinforcement method for a cylindrical tank in the middle of construction, a reaction force is applied to the side plate 102 of the cylindrical tank 100 in the middle of construction (hereinafter simply referred to as “cylindrical tank 100”). Wire 120 is radially radiated from a fixed object 130 such as a jig, a breakwater, or the ground so as to withstand a surface load in a strong wind. One end of the wire 120 is connected to or near the upper end of the side plate 102 of the cylindrical tank 100, the other end is connected to the fixed object 130, and is stretched between the side plate 102 and the fixed object 130. (FIG. 6B). Since a scaffold for construction is installed inside the cylindrical tank 100, it is common to stretch the wire 120 from the outside of the cylindrical tank 100 (FIGS. 6A and 6B).

  Furthermore, as a conventional wind resistant reinforcement method for a cylindrical tank in the middle of construction, Patent Document 1 discloses that a temporary scaffolding is installed in a ring shape to function as a strong wheel, and an outer peripheral walkway / tension ring is provided on the outer surface of the constructed side plate. A provisional assembly method is disclosed.

JP 2000-120276 A

  In the conventional windproof reinforcement method for a cylindrical tank in the middle of construction shown in FIG. 6, the wire 120 is stretched over the entire circumference of the side plate 102 of the cylindrical tank 100. Therefore, for example, there is a large area where heavy equipment such as a crane used for constructing the cylindrical tank 100 and the wire 120 interfere with each other, and there is a problem that the construction of the cylindrical tank 100 is hindered. Further, the number and arrangement of the wires 120 stretched on the cylindrical tank 100 are not strictly determined, and effective reinforcement without excess or deficiency with respect to the wind pressure is not performed.

  Further, in the reinforcing method disclosed in Patent Document 1, it is necessary to provide the temporary scaffold with sufficient out-of-plane rigidity that can withstand wind pressure. For this reason, the temporary scaffold that is temporarily attached is not economical because the strength is higher than necessary. The temporary scaffold is formed of a plurality of members, and a separate structural calculation is required to grasp the strength and deformation characteristics of the temporary scaffold formed of the plurality of members.

  Cylindrical tanks are generally constructed in coastal areas, and in most cases, the prevailing wind direction is limited throughout the year or season. That is, it is a part of the entire cylindrical tank that collapses in a strong wind, and it is not reasonable to reinforce the entire cylindrical tank uniformly as in the prior art.

  This invention is made | formed in view of this situation, and it aims at providing the wind-resistant reinforcement method which can reinforce the cylindrical tank in the middle of a construction reasonably.

The windproof reinforcement method for a cylindrical tank in the middle of construction of the present invention has the following configuration.
[1] A wind-resistant reinforcement method for a cylindrical tank in the middle of construction in which a cylindrical tank in the middle of construction is reinforced against a prevailing wind by stretching a wire from the outside of the cylindrical tank to a side plate of the cylindrical tank in the middle of construction, A wind resistant reinforcement method for a cylindrical tank in the middle of construction, characterized in that a wire is stretched in a range not extending over the entire circumference of the side plate and facing the prevailing wind.
[2] The windproof reinforcement method for a cylindrical tank in the middle of construction according to [1], wherein a plurality of wires are stretched in the circumferential direction of the side plate.
[3] At least three wires are stretched, and in plan view, one of the at least three wires is stretched in a direction of 0 ° to ± 22.5 ° with respect to the prevailing wind direction, and the at least three wires One of the wires is stretched in a direction of 45 ° to 90 ° with respect to the prevailing wind direction, and one wire of the at least three wires is −45 ° to −90 ° with respect to the prevailing wind direction. The windproof reinforcement method for a cylindrical tank in the middle of construction according to [2], characterized by stretching in a direction.
[4] The wind resistant reinforcement method for a cylindrical tank in the middle of construction according to [2] or [3], wherein the wire is stretched at substantially equal intervals in the circumferential direction of the side plate.

  According to the wind-resistant reinforcing method for a cylindrical tank in the middle of construction of the present invention, it is possible to provide reasonable reinforcement to the cylindrical tank in the middle of construction.

FIG. 1 is an explanatory view of a wind-resistant reinforcing method for a cylindrical tank in the middle of construction of the present invention. FIG. 2 is a plan view for explaining an embodiment of a wind-resistant reinforcing method for a cylindrical tank in the course of construction of the present invention. FIG. 3 is a plan view showing a specific example of the embodiment of FIG. FIG. 4 is a plan view showing a specific example of the embodiment of FIG. FIG. 5 is an explanatory diagram of a wind tunnel experiment in which the wind pressure acting on the side plate of the cylindrical tank under construction is measured. FIG. 6 is an explanatory view illustrating an example of a conventional wind-resistant reinforcing method for a cylindrical tank in the middle of construction.

  Hereinafter, an embodiment of a wind-resistant reinforcing method for a cylindrical tank in the middle of construction of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments shown below.

  The wind-resistant reinforcing method for a cylindrical tank in the middle of construction of the present invention is to stretch the wire in a range that does not cover the entire circumference of the side plate of the cylindrical tank that is in the middle of construction and that faces a prevailing wind.

  The present inventors have measured the wind pressure acting on the side plate of the cylindrical tank under construction by wind tunnel experiments (Yasunaga et al., “Wind load for design of open-top oil tanks arranged in series”, Japanese Wind Engineering Society paper. Vol.39, No3, pp53-62, 2014).

FIG. 5 (a) shows the coordinate system of the wind tunnel experiment, FIG. 5 (b) shows an arrangement case of the cylindrical tank examined in the wind tunnel experiment, and FIG. 5 (c) shows a graph of measurement results obtained in the wind tunnel experiment. Indicates the part. In FIG. 5, θ represents the angle of the pressure measurement point with respect to the wind direction. The pressure measurement points were provided at 15 ° intervals on the outer wall surface in the circumferential direction, 30 ° intervals on the inner wall surface, and 6 or 4 levels in the height direction ζ. The wind pressure acting on these pressure measurement points was measured simultaneously at all points for about 33 seconds at a sampling frequency of 1 kHz. Furthermore, as shown in FIG. 5 (b), a dummy tank having the same shape as the cylindrical tank (Dummy model) was produced and arranged together with the cylindrical tank to form a continuous building model. As the arrangement case of the continuous building model, a linear arrangement (arrangement 2-P, 3-E, 3-C) and an arrangement having a two-dimensional expansion (arrangement 4-S, 3-T) were examined. . The setting of the wind direction angles β and β ^* in the continuous building model shown in FIG. 5B was set at 15 ° intervals (45 ° only for the arrangement 3-E). The adjacent building spacing S was examined for S = 1.0D, 0.5D, 0.25D, and 0.125D.

FIG. 5 (c) shows the distribution of the average external pressure coefficient (C _pe ) in the circumferential direction in the case of a single cylindrical tank (isolated) and in the case of arrangement 2-P (S / D = 0.125) of the continuous building model. It is the graph which showed the change by the wind direction angle (beta). In the graph, a range where C _pe is positive is a range where a positive wind pressure is generated. The positive wind pressure has a dominant influence on the buckling phenomenon of the side plate of the cylindrical tank.

As shown in the graph, although the circumferential distribution of C _pe varies depending on the value of β, the positive wind pressure range acting on the side plate of the cylindrical tank is in the range of 0 ° to ± 60 ° with respect to the wind direction. I know that there is. Note that this range is the same for the other arrangement cases of the continuous building model shown in FIG. That is, a range in which a positive wind pressure that has a dominant influence on the buckling phenomenon of the side plate of the cylindrical tank with respect to a specific wind direction is in a range of 0 to ± 60 ° with respect to the wind direction.

  As described above, the construction site of the cylindrical tank is generally a coastal region, and in most cases, the prevailing wind direction is limited throughout the year or season. When the cylindrical tank is reinforced with respect to such a specific wind direction, it is not reasonable to uniformly reinforce the entire cylindrical tank. In other words, in order to reinforce the cylindrical tank in the middle of construction, sufficient out-of-plane rigidity is obtained by partially reinforcing the range dominant in the buckling phenomenon among the side plates of the cylindrical tank, taking into account the prevailing wind direction. Can be obtained.

  A wind-resistant reinforcing method for a cylindrical tank during the construction of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view of a wind-resistant reinforcing method for a cylindrical tank in the middle of construction of the present invention, FIGS. 1 (a) and 1 (b) are plan views thereof, and FIG. 1 (c) is a plan view of FIG. It is a cut part end view in the YY line.

  In the present invention, the range that does not cover the entire circumference of the side plate of the cylindrical tank that is being constructed and that faces the prevailing wind is a range of 0 ° to ± 90 ° with respect to the prevailing wind direction in plan view. (FIG. 1 (a)).

In the present invention, the prevailing wind direction is the direction in which the prevailing wind blows with respect to the center O of the cylindrical tank 10 being constructed (hereinafter simply referred to as “cylindrical tank 10”) in plan view. The direction of the angle α with respect to the prevailing wind direction is a direction that forms an angle α with the prevailing wind direction at the center O of the cylindrical tank 10. For example, FIG. 1B shows that the wire 20 is stretched in the direction of the angle α ₁ with respect to the prevailing wind direction. In the present invention, in a plan view, the clockwise angle with respect to the prevailing wind direction is positive, and the counterclockwise angle is negative. Further, unless otherwise specified, the angles described below are angles in plan view.

  The prevailing wind direction is not particularly limited, but may be determined based on meteorological observation data, or may be determined empirically according to the weather environment in the area where the cylindrical tank is constructed. Examples of the meteorological observation data include meteorological observation data released by the Japan Meteorological Agency, annual wind observation data obtained at a meteorological observation stand near the construction site, and wind conditions obtained by an anemometer installed at the construction site. Observation data can be used.

  As shown in FIG. 1 (a), the wind-resistant reinforcement method for a cylindrical tank in the middle of construction of the present invention is within a range that does not cover the entire circumference of the side plate 12 of the cylindrical tank 10 among the side plates 12 of the cylindrical tank 10, and At least one wire 20 is stretched in a range facing the prevailing wind (a range indicated by A, hereinafter referred to as “range A”). Here, the range A is a range of 0 ° to ± 90 ° (angle α in FIG. 1 is 0 ° to ± 90 °) with respect to the prevailing wind direction.

  This range A includes a range in which positive wind pressure that has a dominant effect on the buckling phenomenon of the side plate of the cylindrical tank described above occurs. In the present invention, the entire cylindrical tank 10 is not uniformly reinforced, but the range A of the side plate 12 of the cylindrical tank 10 is partially reinforced in consideration of the prevailing wind direction. Rigidity is obtained and rational windproof reinforcement is possible.

  The method of stretching the wire 20 from the outside of the cylindrical tank 10 to the side plate 12 of the cylindrical tank 10 is not particularly limited, and can be performed, for example, in the same manner as a conventional method. That is, as shown in FIGS. 1A and 1B, the wire 20 is stretched from the fixed object 30 outside the cylindrical tank 10 to the side plate 12 of the cylindrical tank 10. Preferably, the wire 20 is stretched from the fixed object 30 outside the cylindrical tank 10 toward the center O of the cylindrical tank 10. At that time, one end of the wire 20 is connected to the upper end of the side plate 12 of the cylindrical tank 10 or the vicinity thereof, the other end is connected to the fixed object 30, and the wire 20 is connected between the side plate 12 and the fixed object 30. What is necessary is just to stretch (FIG.1 (c)).

  Preferably, a plurality of wires are stretched in the circumferential direction of the range A. More preferably, the plurality of wires are stretched at substantially equal intervals in the circumferential direction of the range A (the circumferential intervals at the connection points where the wires are connected to the side plates 12 of the cylindrical tank 10 are substantially equal).

  FIG. 2 is a plan view for explaining an embodiment of a wind-resistant reinforcing method for a cylindrical tank in the course of construction of the present invention.

In the wind-resistant reinforcing method shown in FIG. 2, at least three wires of wire 20, wire 22, and wire 24 are used. The wire 20 is stretched in the direction of 0 ° to ± 22.5 ° with respect to the prevailing wind direction (range A _{1 in} FIG. 2), and the wire 22 is stretched in the direction of 45 ° to 90 ° with respect to the prevailing wind direction (same range). tension in a _2), stretched in the direction of -45 ° ~-90 ° the wire 24 against the prevailing wind direction (the range _{a 3).}

Among the range A _1, it is preferable to tension the wire 20 to prominence wind direction (0 ° with respect to prevailing wind direction). Among the above-mentioned range _{A 2,} tension in the direction of 45 ° to 75 ° with respect to the wire 22 excellence wind direction, among the above-mentioned range _{A 3,} of -45 ° to 75 ° the wire 24 against the prevailing wind direction It is preferable to stretch in the direction. Further, the wires 20, 22, 24 are arranged at approximately equal intervals in the circumferential direction of the side plate 12 of the cylindrical tank 10 (the connection point 20 a connecting the wire 20 to the side plate 12 of the cylindrical tank 10 and the wire 22 to the side plate 12 of the cylindrical tank 10. The circumferential distance between the connected connecting points 22a and the distance between the connecting points 20a and the connecting points 24a connecting the wires 24 to the side plates 12 of the cylindrical tank 10 are substantially equal. preferable.

  FIG. 3 is a plan view showing a specific example of the embodiment shown in FIG. The wind-resistant reinforcing method shown in FIG. 3 is obtained by stretching the wire 20 in the prevailing wind direction, stretching the wire 22 in the direction of 45 ° with respect to the prevailing wind direction, and stretching the wire 24 in the direction of −45 ° with respect to the prevailing wind direction. It is. In this wind-resistant reinforcing method, the wire 23 is stretched in the direction of 90 ° with respect to the prevailing wind direction, and the wire 25 is stretched in the direction of −90 ° with respect to the prevailing wind direction.

  FIG. 4 is a plan view showing a specific example of the embodiment shown in FIG. The wind-resistant reinforcing method shown in FIG. 4 is obtained by stretching the wire 20 in the prevailing wind direction, stretching the wire 22 in the direction of 60 ° with respect to the prevailing wind direction, and stretching the wire 24 in the direction of −60 ° with respect to the prevailing wind direction. It is.

  By stretching the wire as described above, the range dominant to the buckling phenomenon of the side plate of the cylindrical tank can be reinforced more effectively with a smaller number of wires, and it is more economical and more rational. Wind-proof reinforcement is possible. Among the above-described embodiments, the wind-resistant reinforcing method shown in FIG. 4 is particularly preferable.

  According to the wind-resistant reinforcement method of the cylindrical tank in the middle of the construction of the present invention described above, it is possible to obtain sufficient out-of-plane rigidity by partially reinforcing the side plate of the cylindrical tank in consideration of the prevailing wind direction. Unlike the technology, it is not necessary to uniformly reinforce the entire cylindrical tank by, for example, extending a wire around the entire circumference of the cylindrical tank in the middle of construction, and rational wind-resistant reinforcement can be applied to the cylindrical tank in the middle of construction.

  According to the wind resistant reinforcement method for a cylindrical tank in the middle of the construction of the present invention, the range in which the wire is stretched to the side plate of the cylindrical tank is limited, so that a wide working space can be secured and the cylindrical tank is efficiently constructed. it can. Furthermore, an efficient manufacturing process can be planned by specifying the place where a wire is stretched.

  According to the wind resistant reinforcement method for a cylindrical tank in the middle of the construction of the present invention, the tension acting on one wire in a strong wind is clarified by clarifying the wind direction to be reinforced. Therefore, the necessary cross section of the wire can be easily calculated without requiring a complicated structural calculation.

  The wind-resistant reinforcing method shown in FIG. 4 is particularly preferable because these effects can be enjoyed more.

10, 100 Cylindrical tank 20, 22-25, 120 Wire 30, 130 fixed object in the middle of construction

Claims (4)

A wind-resistant reinforcing method for a cylindrical tank in the middle of construction that reinforces the cylindrical tank in the middle of construction against the prevailing wind by stretching a wire from the outside of the cylindrical tank to the side plate of the cylindrical tank in the middle of construction,
A wind resistant reinforcement method for a cylindrical tank in the middle of construction, characterized in that a wire is stretched in a range not extending over the entire circumference of the side plate and facing the prevailing wind.   The wind resistant reinforcement method for a cylindrical tank in the middle of construction according to claim 1, wherein a plurality of wires are stretched in a circumferential direction of the side plate. Stretch at least three wires,
In plan view, one of the at least three wires is stretched in a direction of 0 ° to ± 22.5 ° with respect to the prevailing wind direction,
One of the at least three wires is stretched in a direction of 45 ° to 90 ° with respect to the prevailing wind direction,
The wind resistant reinforcement method for a cylindrical tank in the middle of construction according to claim 2, wherein one of the at least three wires is stretched in a direction of -45 ° to -90 ° with respect to a prevailing wind direction.   The wind resistant reinforcement method for a cylindrical tank in the middle of construction according to claim 2 or 3, wherein the wire is stretched at substantially equal intervals in the circumferential direction of the side plate.

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