JP6579877B2 - How to adjust the hanging height of a structure - Google Patents

Description

The present invention relates to a method for adjusting a suspended vertical of a structure.

  In recent years, semi-submersibles have been moored in the seas where oil and gas fields are located, and are increasingly used for offshore resource development as offshore oil and gas production facilities.

  The semi-submersible is a semi-submersible floating structure in which the lower part of a structure having a truss structure or a ramen structure is submerged below the sea surface. Drilling rigs or oil / gas production facilities are installed on the floating structure. It is designed to be used.

  The semi-submersible is a very large structure, and may be manufactured separately in an upper structure and a lower structure in the dock in order to perform efficient manufacturing. As an example of the assembly procedure, after the manufacture of the upper structure and the lower structure is completed, the upper structure is suspended by a portal crane such as a Goliath crane disposed so as to straddle the dock. Lift at a point. Subsequently, the dock is filled with water, and the lower structure is floated on the water and moved below the upper structure. In this state, the upper structure is suspended and placed on the lower structure, and the upper structure and the lower structure are coupled.

  In addition, while intensively monitoring load fluctuations at a plurality of hanging points, as a general technical level related to lifting heavy objects that perform a lifting operation while maintaining the posture of the suspended load constant, for example, There exists patent document 1. FIG.

JP 2004-123248 A

  By the way, in the case of two-point suspension, even if there is a difference in height due to bending of a large structure as a girder or a suspended load, or elongation of a wire rope, distribution of the load is not affected.

  However, when a large structure is lifted by a wire rope at a large number of suspension points at three or more points and the hoisting drive device at each suspension point is independent, if there is a difference in height between the suspension points, There was a problem that the distribution would fluctuate.

  In addition, in what is disclosed by patent document 1, it is not considered at all about the bending of the large sized structure as a girder or a suspended load, or the elongation of a wire rope.

The present invention has been made in view of the above-described conventional problems, and can eliminate the difference in height position of each suspension point to minimize the load distribution variation, while maintaining the structure horizontally. An object of the present invention is to provide a method for adjusting the lifting and lowering of a structure that can be smoothly lifted and lowered.

The present invention is a structure lifting adjustment method for lifting a structure at three or more hanging points by wire ropes fed from a plurality of winch drums arranged in a girder extending in the horizontal direction,
A temporary hoisting step in which the hoisting torque of each winch drum is set to the same value at which the structure does not float from the ground, thereby applying the same tension to each wire rope to eliminate loosening; and
A ground cutting step in which the wire rope that has been loosened in the temporary winding step is wound up at a constant speed by each winch drum, and the structure is stopped in a state of being lifted from the ground;
Lifting and unwinding each winch drum individually so that the height position of the suspension points at both ends of the structure is the same at the both ends of the structure lifted from the ground in the ground cutting process Position adjustment process,
Winding in which the height positions of the suspension points at both ends of the same structure are set as 0 points and the height positions of the other suspension points are set as 0 points in the same structure in the height position adjustment process at both ends when winding. An upper zero correction process;
A hoisting step of hoisting each winch drum at a constant speed from the zero point height position of each hanging point set in the hoisting zero point correction step;
While each winch drum is being wound at a constant speed in the winding process, the height position of each hanging point is measured every set time, and the height position of the hanging point set as a reference and the other hanging points are measured. It is determined whether or not the displacement difference from the height position is outside the threshold value. If the displacement difference is not outside the threshold value, the hoisting process is continued, and if the displacement difference is outside the threshold value, The hoisting point height monitoring process at the time of hoisting that is once stopped and returned to the hoisting point height position adjusting process at both ends at hoisting;
At least one load among the loads acting on each winch drum is set to stop while any one of the above-mentioned ground cutting process and the hoisting point height position adjusting process at the both ends during winding and the winding process is performed. It is determined whether or not the value exceeds the value, and if the at least one load does not exceed the set stop value, any of the ground cutting step, the lifting point height position adjusting step during winding, and the winding step If the at least one load exceeds the stop set value, the hoisting is temporarily stopped, and the height position of each hanging point is adjusted to make the load equal to or less than the stop set value. And a hoisting load monitoring process for returning to the hoisting point height position adjusting process at both ends when hoisting.

  In the suspension vertical adjustment method for the structure, the stop set value of the load is preferably a value obtained by dividing the suspension rated load of the entire apparatus by the number of winch drums.

Moreover, in the hanging up and down adjustment method of the structure, the structure is an upper structure placed on the lower structure,
It is determined whether or not the upper structure has reached a predetermined height in the winding step, and the winding completion step of stopping the winding when the upper structure reaches the predetermined height; and
A lowering step of lowering each winch drum at a constant speed after transferring the lower structure to a position below the upper structure where the winding is stopped in the winding completion step;
While each winch drum is being wound at a constant speed in the unwinding step, the height position of each hanging point is measured at each set time, and the height position of the hanging point set as a reference and other hanging points are measured. It is determined whether or not the displacement difference from the height position is outside the threshold, and when the displacement difference is not outside the threshold, the unwinding process is continued, and when the displacement difference is outside the threshold Is a suspension point height monitoring process to stop the lowering once,
When the unwinding is stopped in the unwinding suspending point height monitoring step, the winch drums are individually unwound and unwound so that the height positions of the suspending points at both ends of the upper structure are the same. At the time of both ends hanging point height position adjustment process,
The height positions of the suspension points at both ends of the upper structure that are the same in the both-end suspension point height adjustment process at the time of unwinding are set as 0 points, and the height positions of the other suspension points are set as 0 points. , A zero point correction process at the time of unwinding to return to the unwinding process,
Whether or not at least one load of the winch drums exceeds a stop set value while any one of the both-end lifting point height position adjusting step and the lowering step at the time of lowering is being performed. And if the at least one load does not exceed the set stop value, continue either one of the both-end suspension point height position adjusting step and the lowering step during lowering, and the at least one load When the value exceeds the stop set value, the lowering is temporarily stopped, the height position of each hanging point is adjusted to make the load equal to or less than the stop set value, and then the both-end hanging point height position at the time of lowering is set. A lowering load monitoring process for returning to the adjustment process;
It is determined whether or not the upper structure that has been lowered in the lowering process is placed on the lower structure, and the lowering is stopped when the upper structure is placed on the lower structure. It is preferable to perform the unwinding completion step.

According to the lifting / lowering adjustment method for a structure of the present invention, the difference in height position of each hanging point can be eliminated to minimize the variation in load distribution, and the structure can be suspended smoothly while being held horizontally. An excellent effect of raising and lowering can be achieved.

In the Example of the hanging up-and-down adjustment method of the structure of this invention, it is a front view which shows the initial state before lifting. In the Example of the hanging up-and-down adjustment method of the structure of this invention, it is a front view which shows the state which gave the same tension | tensile_strength to each wire rope and eliminated looseness. In the Example of the hanging up-and-down adjustment method of the structure of this invention, it is a front view which shows the state which the structure floated from the ground. It is a front view which shows the state which the structure reached | attained predetermined height in the Example of the hanging up-and-down adjustment method of the structure of this invention. FIG. 5 is a front view showing a state in which each winch drum is wound at a constant speed after the lower structure is transferred to the lower position of the structure in the embodiment of the method for adjusting the vertical suspension of the structure of the present invention. In the Example of the hanging up-and-down adjustment method of the structure of this invention, it is a front view which shows the state which mounted the structure on the lower structure. It is a perspective view which shows the example of arrangement | positioning of the wire rope paid out from a winch drum, and the example of arrangement | positioning of a pin type load cell (load meter) in the Example of the hanging up-and-down adjustment method of the structure of this invention. In the Example of the hanging up-and-down adjustment method of the structure of this invention, it is a perspective view which shows the example of an arrangement | positioning of the wire rope paid out from a winch drum, and the example of arrangement | positioning of a tension type load cell (load meter). It is a flowchart which shows the flow of the operation | movement from the temporary winding process to the winding process in the Example of the hanging up-and-down adjustment method of the structure of this invention. It is a flowchart which shows the operation | movement flow from the unwinding process to the coupling | bonding process in the Example of the hanging-up-and-down adjustment method of the structure of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1-10 is an Example of the hanging-up-and-down adjustment method of the structure of this invention.

  In this embodiment, a semi-submersible upper structure 2A and a lower structure 2B are manufactured separately in the dock 1, and the upper structure is formed by a portal crane 3 such as a Goliath crane disposed so as to straddle the dock 1. An example in which 2A is lifted at a plurality of hanging points X and is finally coupled to the lower structure 2B will be described.

  The portal crane 3 includes a leg 4 erected on the peripheral edge of the dock 1, and a girder 5 disposed so as to span between the upper ends of the leg 4 and extending horizontally. The upper part at three or more hanging points X is provided by wire ropes 7 fed out from a plurality of winch drums 6 (four in each example, four on each side in the example of FIGS. 1 to 6) arranged on the girder 5. The structure 2A is lifted and lowered.

  For example, as shown in FIGS. 7 and 8, the wire rope 7 fed out from the winch drum 6 is lifted and lowered with a number of fixed sheaves 9 constituting four sets of suspended sheave units 8 arranged in the longitudinal direction of the girder 5. It is wound around the sheave 10 sequentially. In each set of suspended sheave units 8, the fixed sheave 9 is disposed in the girder 5 as a set of five in the horizontal direction perpendicular to the longitudinal direction of the girder 5. Are attached to the sheave bracket 11 in a horizontal direction perpendicular to the longitudinal direction of the girder 5 and are suspended from the fixed sheave 9. An intermediate drum 12 is disposed between the second set of suspended sheave units 8 and the third set of suspended sheave units 8 counted from the winch drum 6 side, and the wire rope 7 is wound around the intermediate drum 12. It is hung. In each set of suspended sheave units 8, a suspended bracket 13 that is connected to the upper surface of the upper structure 2A and that constitutes the suspended point X is pivotally attached to a sheave bracket 11 to which the elevating sheave 10 is attached. However, the example of the wire rope 7 shown in FIGS. 7 and 8 is merely an example, and is not limited thereto. In addition, the said sheave bracket 11 is connected by the coupling material 14 (refer FIGS. 1-6) which is abbreviate | omitting illustration in FIG.7 and FIG.8 as a set of four.

  The girder 5 is provided with a distance meter 15 for measuring the height position of the hanging point X. As the range finder 15, for example, a laser range finder can be adopted. In this case, as shown in FIGS. 1 to 6, the range finder 15 as the laser range finder is attached to the suspension bracket 13. A reflection plate 16 that reflects the laser beam projected from the light source may be provided.

  The girder 5 is provided with a load meter 17 for measuring a load acting on the winch drum 6. As the load cell 17, for example, a pin type or tension type load cell can be adopted. When the pin type load cell is used as the load meter 17, for example, as shown in FIG. 7, the fixed sheave 9 located at both ends of the second set of suspended sheave units 8 and the opposite ends of the third set of suspended sheave units 8 are used. A pin-type load cell (load meter 17) may be disposed concentrically with the fixed sheave 9 and the load applied to the fixed sheave 9 may be measured as a load acting on the winch drum 6. When the tension type load cell is used as the load meter 17, for example, as shown in FIG. 8, the other end of the tension type load cell (load meter 17) is fixed so that one end is suspended in the girder 5. What is necessary is to arrange | position so that it may connect with the support shaft 18 of the intermediate drum 12, and to measure the load added to the intermediate drum 12 as a load which acts on the said winch drum 6.

  The height position of the hanging point X measured by the distance meter 15 and the load measured by the load meter 17 are sent to the controller 19 as a position signal 15a and a load signal 17a as shown in FIG. 7 or FIG. The controller 19 winds up the motor M of the winch drum 6 based on the height position of the hanging point X measured by the distance meter 15 and the load measured by the load meter 17. A drive signal 6a for controlling the lowering is output.

  Next, the operation of the above embodiment will be described.

  First, as shown in FIG. 1, a suspension bracket 13 is connected to the upper surface of a semi-submersible upper structure 2 </ b> A manufactured in the dock 1.

  Subsequently, as shown in FIG. 2, by setting the hoisting torque of each winch drum 6 to the same value that the upper structure 2A does not lift from the ground, the same tension is applied to each wire rope 7 to loosen it. lose. This is shown as a temporary winding process in the flowchart of FIG. 9 (see step S1).

  The wire rope 7 that has been loosened in the temporary winding step is wound up at a constant speed by the winch drums 6 and stopped in a state where the upper structure 2A is lifted from the ground as shown in FIG. This is shown as a ground cutting process in the flowchart of FIG. 9 (see step S2).

  The winch drums 6 are individually wound and unwound so that the height structures of the suspension points X at both ends of the upper structure 2A are the same in the upper structure 2A that is lifted from the ground in the ground cutting step. This is shown in the flowchart of FIG. 9 as a step for adjusting the height position of the lifting points at both ends when winding (see step S3).

  The height position of the suspension point X at both ends of the upper structure 2A, which is the same in the both-end suspension point height position adjusting step at the time of winding, is set as 0 point, and the height position of the other suspension point X is 0 point And the rangefinder 15 is corrected. This is shown as the winding zero point correction step in the flowchart of FIG. 9 (see step S4).

  Each winch drum 6 is wound at a constant speed from the zero point height position of each hanging point X set in the winding zero point correction step. This is shown as a winding process in the flowchart of FIG. 9 (see step S5).

  While each winch drum 6 was wound at a constant speed in the winding step, the height position of each hanging point X was measured by the distance meter 15 every set time (for example, one second) and set as a reference. It is determined whether or not the displacement difference between the height position of the hanging point X and the height position of the other hanging point X is out of the threshold value. If the displacement difference is not out of the threshold value, the hoisting step If the displacement difference deviates from the threshold value, the hoisting is temporarily stopped and the process is returned to the hoisting point height position adjusting step at the time of hoisting. This is shown in the flowchart of FIG. 9 as a hoisting point height monitoring step during winding (see step S6 and step S7).

  At least one of the loads acting on each winch drum 6 is stopped while any one of the above-mentioned ground cutting process, hoisting point height position adjusting process at hoisting and hoisting process is being performed. It is determined whether or not the set value is exceeded, and when the at least one load does not exceed the stop set value, the ground cutting step and the both-end lifting point height position adjusting step and the hoisting step during the hoisting are included. Any one of the steps is continued, and when the at least one load exceeds the stop set value, the winding is temporarily stopped, and the height position of each hanging point X is adjusted to make the load equal to or less than the stop set value. After that, the process is returned to the step of adjusting the height position of the lifting points at both ends when winding. This is shown as a hoisting load monitoring step in the flowchart of FIG. 9 (see step S81, step S82, step S83, step S9 and step S10). The operation of setting the load to the stop set value or less is performed by the operator of the portal crane 3 finely adjusting the winding / lowering of the winch drum 6 individually, or by the superstructure of the operator and the slinging worker in cooperation with each other. This is done by changing the suspension point X for the object 2A.

  Here, the stop set value of the load is set as a value obtained by dividing the lifting rated load of the entire apparatus by the number of winch drums 6. As the load alarm set value, for example, a value of (rated load / number of winch drums 6) × 0.9 is set in advance, and an alarm is issued when the load reaches the alarm set value. The operator of the type crane 3 and the slinging worker may be alerted.

  In the winding process, it is determined whether or not the upper structure 2A has reached a predetermined height, and the winding is stopped when the upper structure 2A reaches a predetermined height as shown in FIG. This is shown as a hoisting completion process in the flowchart of FIG. 9 (see step S11 and step S12). The predetermined height is a height that does not hinder the transfer of the lower structure 2B to the lower structure 2A, and the winding is stopped at the operator's discretion. A height that does not hinder the transfer of the lower structure 2B below the upper structure 2A is input in advance to the controller 19, and the suspension point X measured by the distance meter 15 is input. The winding may be automatically stopped based on the height position.

  When the winding is stopped in the winding completion step, as shown in FIG. 5, water is poured into the dock 1, the lower structure 2B is transferred to a position below the upper structure 2A, and then each winch drum 6 is wound at a constant speed. Lower. This is shown as a lowering process in the flowchart of FIG. 10 (see step S13).

  While each winch drum 6 is being wound at a constant speed in the unwinding step, the height position of each hanging point X is measured by the distance meter 15 every set time (for example, one second) and set as a reference. It is determined whether or not the displacement difference between the height position of the hanging point X and the height position of the other hanging point X is outside the threshold value, and if the displacement difference is not outside the threshold value, the lowering The process is continued, and when the displacement difference is outside the threshold value, the lowering is temporarily stopped. This is shown in the flowchart of FIG. 10 as a step of monitoring the suspension point height at the time of lowering (see step S14 and step S15).

  When the unwinding is stopped in the unwinding suspension point height monitoring step, each winch drum 6 is individually unwound and wound so that the height positions of the suspension points X at both ends of the upper structure 2A are the same. To do. This is shown in the flowchart of FIG. 10 as a step for adjusting the height position of the suspension points at both ends during the lowering (see step S16).

  The height position of the suspension point X at both ends of the upper structure 2A, which is the same in the both-end suspension point height position adjusting step at the time of unwinding, is set as 0 point, and the height positions of the other suspension point X are 0 points. And return to the unwinding step. This is shown in the flowchart of FIG. 10 as a zero point correction process at the time of lowering (see step S17).

  Whether or not at least one of the winch drums 6 exceeds a stop set value while any one of the both-end lifting point height position adjusting step and the lowering step at the time of lowering is being performed. And when the at least one load does not exceed the stop set value, continue any one of the both-end suspension point height position adjusting step and the unwinding step during unwinding, and the at least one load When the load exceeds the stop set value, the lowering is temporarily stopped, and the height position of each hanging point X is adjusted to make the load equal to or less than the stop set value. Return to the position adjustment process. This is shown in the flowchart of FIG. 10 as a load-lowering load monitoring step (see step S181, step S182, step S19, and step S20). The operation of setting the load to the stop set value or less is performed by the operator of the portal crane 3 finely adjusting the winding / lowering of the winch drum 6 individually, or by the superstructure of the operator and the slinging worker in cooperation with each other. This is done by changing the suspension point X for the object 2A.

  It is determined whether or not the upper structure 2A unwound in the unwinding step is placed on the lower structure 2B, and when the upper structure 2A is placed on the lower structure 2B. Stop the lowering. This is shown as a lowering completion step in the flowchart of FIG. 10 (see step S21 and step S22). In the unwinding completion process, under the supervision of the operator of the portal crane 3 and the slinging worker, the upper structure 2A and the lower structure 2B are finely adjusted and coupled to each other, and the wire rope 7 The slack worker confirms that the slack has been sufficiently loosened and signals the operator so that the operator stops the lowering.

  As a result, when a large structure such as the semi-submersible superstructure 2A is lifted by the wire rope 7 at three or more hanging points X, the winch drum 6 that is the hoisting drive device for each hanging point X is independent. Even in this case, it is possible to avoid a difference in height between the hanging points X, and there is no fear of fluctuations in load distribution.

  Thus, the difference in the height position of each hanging point X can be eliminated to minimize the variation in load distribution, and the structure can be smoothly lifted and lowered while being held horizontally.

  In this embodiment, the set stop value of the load is a value obtained by dividing the hoisting rated load of the entire apparatus by the number of winch drums 6, so that an unreasonable load is applied to the winch drum 6 beforehand. Can be prevented.

In this embodiment, the structure is an upper structure 2A placed on the lower structure 2B.
A winding completion step of determining whether or not the upper structure 2A has reached a predetermined height in the winding process, and stopping winding when the upper structure 2A reaches a predetermined height;
A lowering step in which the winch drum 6 is wound at a constant speed after the lower structure 2B is transferred to a position below the upper structure 2A that has been unwound in the winding completion step;
While each winch drum 6 is being wound at a constant speed in the unwinding step, the height position of each hanging point X is measured at every set time, and the height position of the hanging point X set as a reference and the others It is determined whether or not the displacement difference from the height position of the hanging point X is out of the threshold value. If the displacement difference is not out of the threshold value, the unwinding step is continued, and the displacement difference exceeds the threshold value. When it falls off, the hanging point height monitoring process at the time of unwinding temporarily stops the unwinding,
When the unwinding is stopped in the unwinding suspension point height monitoring step, each winch drum 6 is individually unwound and wound so that the height positions of the suspension points X at both ends of the upper structure 2A are the same. The step of adjusting the height position of the suspension points at both ends when rolling down,
The height position of the suspension point X at both ends of the upper structure 2A, which is the same in the both-end suspension point height position adjusting step at the time of unwinding, is set as 0 point, and the height positions of the other suspension point X are 0 point And a zero point correction step when lowering to return to the lowering step,
Whether or not at least one of the winch drums 6 exceeds a stop set value while any one of the both-end lifting point height position adjusting step and the lowering step at the time of lowering is being performed. And when the at least one load does not exceed the stop set value, continue any one of the both-end suspension point height position adjusting step and the unwinding step during unwinding, and the at least one load When the load exceeds the stop set value, the lowering is temporarily stopped, and the height position of each hanging point X is adjusted to make the load equal to or less than the stop set value. The unwinding load monitoring process to return to the position adjustment process,
It is determined whether or not the upper structure 2A unwound in the unwinding step is placed on the lower structure 2B, and when the upper structure 2A is placed on the lower structure 2B. The unwinding completion process for stopping the unwinding is performed, so that the suspended upper structure 2A eliminates the difference in the height position of each hanging point X and minimizes the variation in load distribution. On the other hand, it can be held horizontally and hung smoothly to be coupled to the lower structure 2B.

It should be noted that the method for adjusting the hanging up and down of the structure of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

1 Dock 2A Superstructure (Structure)
2B Substructure 3 Gate Crane 5 Girder 6 Winch Drum 6a Drive Signal 7 Wire Rope 15 Distance Meter 15a Position Signal 17 Load Meter 17a Load Signal 19 Controller X Hanging Point

Claims (3)

A method for adjusting the lifting and lowering of a structure by lifting a structure at three or more hanging points by wire ropes fed from a plurality of winch drums arranged on a girder extending in a horizontal direction,
A temporary hoisting step in which the hoisting torque of each winch drum is set to the same value at which the structure does not float from the ground, thereby applying the same tension to each wire rope to eliminate loosening; and
A ground cutting step in which the wire rope that has been loosened in the temporary winding step is wound up at a constant speed by each winch drum, and the structure is stopped in a state of being lifted from the ground;
Lifting and unwinding each winch drum individually so that the height position of the suspension points at both ends of the structure is the same at the both ends of the structure lifted from the ground in the ground cutting process Position adjustment process,
Winding in which the height positions of the suspension points at both ends of the same structure are set as 0 points and the height positions of the other suspension points are set as 0 points in the same structure in the height position adjustment process at both ends when winding. An upper zero correction process;
A hoisting step of hoisting each winch drum at a constant speed from the zero point height position of each hanging point set in the hoisting zero point correction step;
While each winch drum is being wound at a constant speed in the winding process, the height position of each hanging point is measured every set time, and the height position of the hanging point set as a reference and the other hanging points are measured. It is determined whether or not the displacement difference from the height position is outside the threshold value. If the displacement difference is not outside the threshold value, the hoisting process is continued, and if the displacement difference is outside the threshold value, The hoisting point height monitoring process at the time of hoisting that is once stopped and returned to the hoisting point height position adjusting process at both ends at hoisting;
At least one load among the loads acting on each winch drum is set to stop while any one of the above-mentioned ground cutting process and the hoisting point height position adjusting process at the both ends during winding and the winding process is performed. It is determined whether or not the value exceeds the value, and if the at least one load does not exceed the set stop value, any of the ground cutting step, the lifting point height position adjusting step during winding, and the winding step If the at least one load exceeds the stop set value, the hoisting is temporarily stopped, and the height position of each hanging point is adjusted to make the load equal to or less than the stop set value. And a hoisting load monitoring process for returning to the hoisting point height position adjusting process at both ends when hoisting.   The suspension lifting and lowering adjustment method for a structure according to claim 1, wherein the stop set value of the load is a value obtained by dividing the lifting rated load of the entire apparatus by the number of winch drums. The structure is an upper structure placed on the lower structure,
It is determined whether or not the upper structure has reached a predetermined height in the winding step, and the winding completion step of stopping the winding when the upper structure reaches the predetermined height; and
A lowering step of lowering each winch drum at a constant speed after transferring the lower structure to a position below the upper structure where the winding is stopped in the winding completion step;
While each winch drum is being wound at a constant speed in the unwinding step, the height position of each hanging point is measured at each set time, and the height position of the hanging point set as a reference and other hanging points are measured. It is determined whether or not the displacement difference from the height position is outside the threshold, and when the displacement difference is not outside the threshold, the unwinding process is continued, and when the displacement difference is outside the threshold Is a suspension point height monitoring process to stop the lowering once,
When the unwinding is stopped in the unwinding suspending point height monitoring step, the winch drums are individually unwound and unwound so that the height positions of the suspending points at both ends of the upper structure are the same. At the time of both ends hanging point height position adjustment process,
The height positions of the suspension points at both ends of the upper structure that are the same in the both-end suspension point height adjustment process at the time of unwinding are set as 0 points, and the height positions of the other suspension points are set as 0 points. , A zero point correction process at the time of unwinding to return to the unwinding process,
Whether or not at least one load of the winch drums exceeds a stop set value while any one of the both-end lifting point height position adjusting step and the lowering step at the time of lowering is being performed. And if the at least one load does not exceed the set stop value, continue either one of the both-end suspension point height position adjusting step and the lowering step during lowering, and the at least one load When the value exceeds the stop set value, the lowering is temporarily stopped, the height position of each hanging point is adjusted to make the load equal to or less than the stop set value, and then the both-end hanging point height position at the time of lowering is set. A lowering load monitoring process for returning to the adjustment process;
It is determined whether or not the upper structure that has been lowered in the lowering process is placed on the lower structure, and the lowering is stopped when the upper structure is placed on the lower structure. The method for adjusting the suspended height of the structure according to claim 1 or 2, wherein the unwinding completion step is performed.

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