WO2020095697A1 - Method for constructing marine structure, and work ship - Google Patents

Abstract

A part or all of a work ship 1A is lowered using a spud raising and lowering operation for raising and lowering spuds 20A, 20B of a deck raising and lowering system provided to the work ship 1A, whereby an upper structure 41 mounted on the work ship 1A is raised and lowered on a lower structure 42, and the two structures are joined and integrated. It is thereby possible to move the upper structure, which is assembled and integrated on land and conveyed using the work ship, up and down without using suspension equipment such as a large crane, and more quickly than by draft adjustment of the work ship using ballast adjustment, and to join the upper structure to the lower structure disposed in the installation sea region safely and in a short period of time.

Description

Construction method of offshore structure and work pontoon

The present invention relates to a method of constructing an offshore structure equipped with a wind turbine generator and the like, and a work pontoon.

Offshore structures equipped with wind turbines and other wind turbine generators are generally manufactured as upper and lower structures. This superstructure is generally composed of towers, nacelles, blades and the like. On the other hand, as the lower structure, in the case of a landing type offshore structure, there is a mounting table such as a pile, a gravity type, a jacket, a tripod and a tripile. In the case of a floating offshore structure, there is a columnar tower structure moored by anchors and mooring lines (in the case of a spar type).

In the construction method in which the upper structure and the lower structure are integrated and installed in the installation water area on the ocean, in many cases, there is a step of fixing or holding the lower structure in the upright state in water, and after that step The work of mounting and fixing the upper structure on the upper end of the lower structure on the water surface is performed. The work of sequentially mounting and superposing these upper structures on the lower structures is often carried out using a crane ship.

However, in such a case, there is a problem that a crane ship that is expensive to use is required, and that an upper structure such as a tower that is suspended by a crane is easily affected by wind and the installation work is difficult. ..

For joining work using this crane ship, for example, as described in Japanese Unexamined Patent Publication No. 2012-76738, a semi-vehicle equipped with a deck lifting pedestal system (jackup system) and a movable crane. In a submersible work platform (SEP), a method has been proposed in which the deck lifting pedestal is extended and bottomed to make the work platform fixed and stable, and then the wind turbine is lowered to the seabed by the mounted crane. ing.

Similarly, for example, as described in Japanese Unexamined Patent Application Publication No. 2011-42257, a connected self-elevating work platform ship (SEP) is jacked up on the ocean to be fixed to a stable state. , A method of sequentially hoisting the assembly members of the tower mast by a mounted crane and installing them on a foundation has been proposed.

Furthermore, for example, as described in Japanese Unexamined Patent Publication No. 2012-107586, in an offshore wind turbine installation vessel equipped with jack-up legs, the vessel travels not in the crane but in the longitudinal direction of the hull and further in the width direction of the vessel. It has been proposed to hold and lift a tower of a wind turbine with such a handling device to install the wind turbine on a foundation.

Further, for example, as described in Japanese Unexamined Patent Publication No. 2012-76622, in a deck lifting type work berth provided with a plurality of legs for vertically moving the pontoon main body, A construction method of an offshore wind power generation facility in which a monopile or tower-integrated wind turbine is erected from a laid state or an obliquely laid state to a vertical state by a moving erection device and lowered to a predetermined position is also proposed.

However, with the method of using the crane, the handling device, and the erecting device mounted on these self-lifting work pontoons (SEPs), all of them are a crane or a dedicated crane for lifting or erecting the upper structure. There is a problem in that a device is required, and the weight of the work pontoon increases, so that the work pontoon becomes large.

In view of these problems, the tower, nacelle, blades, etc. are assembled on land and integrated to form an upper structure, and then this upper structure is constructed by a work pontoon (without the deck lifting legs). A method has been proposed in which the upper structure is joined to the lower structure without using a crane or a special device by transporting and moving the structure onto the lower structure installed on the sea.

For example, as described in Japanese Unexamined Patent Publication No. 2016-22783, in a method for constructing an offshore structure that assumes a floating type lower structure, an upper structure mounted on a carrier ship before the joining is started. Keep a sufficient vertical distance (upper and lower distance) between the lower structures, and immediately before the start of joining, pull the lower structure toward the upper structure with a winch, etc. A method has been proposed to gradually suppress and enable safe joining.

With this method, when separating the joined structure of the lower structure and the upper structure from the carrier after completing the joining, by gradually adjusting the ballast to sink the part of the carrier, the joined body is gradually floated. , The joint is removed from the carrier in a short time.

Further, for example, as described in Japanese Unexamined Patent Publication No. 2017-44141, in a method of erection of an offshore wind turbine assuming a landing type lower structure, a base constituting the wind turbine is installed at a erection site. It has been proposed to install a base on the upper part of the foundation by adjusting the draft of the floating body (fork with a fork) that supports the wind turbine on the sea after increasing the ballast water.

In this method, in the step of approaching the upper structure mounted on the work pontoon to the lower structure before joining, and in the step of separating the joined body from the work pontoon after joining the upper structure and the lower structure, respectively. The vertical distance between them is controlled by adjusting the ballast of the work table ship.

When joining the upper structure and the lower structure by such ballast adjustment of the work pontoon, at the start of joining, the upper structure mounted on the work pontoon is moving integrally with the work pontoon, After the joining is completed, the upper structure will move together with the lower structure.Therefore, before the start of the joining, the completion of the joining between the upper structure and the lower structure mounted on the work table ship. After that, it is necessary to maintain an appropriate distance (distance) between the joint body and the work pontoon in order to avoid collision between them.

In particular, in joining work, generally, the hull motion of a work pontoon due to waves and swells has a cycle of several seconds to several tens of seconds. Therefore, between the upper structure and the lower structure mounted on the work pontoon, The distance in the vertical direction also changes in this cycle, and there is a possibility of collision in each cycle. In order to avoid this collision, the timing of approaching the undercarriage of the work pontoon ship and the timing of detachment from the joint after installation, etc. is left to a trained operator, which imposes a heavy burden on the operator. Therefore, a change in the distance between the upper structure and the lower structure and between the work platform and the joint (especially the distance in the vertical direction) caused by the hull motion of the work platform quickly changes, for example, quickly. However, a construction method that can respond within tens of seconds is desired.

However, in the case of a ballast system of a general work pontoon, it takes about 10 minutes or more to adjust the ballast just to raise or lower the front end or the rear end of the hull by several tens of centimeters, and avoid collision before and after joining. From the point of view, it is not enough time.

On the other hand, in a self-lifting work platform (SEP), it is configured so that it can be moved by using a deck lifting leg (spud) as described in Japanese Patent Laid-Open No. 2012-45970, for example. A mobile (walking) work platform has been proposed. For example, after inclining a spud (legs for raising and lowering the deck) configured in the rocking device in any direction of the entire circumference, after returning to the vertical direction or inclining in any direction of the entire circumference, A work boat has been proposed which can be stably moved as a whole in any direction around the hull by repeating tilting in the opposite direction.

Further, for example, as described in Japanese Unexamined Patent Publication No. 11-310189, at least one support frame of the support frames for supporting the spud on the boat main body is supported on the boat main body so as to be horizontally movable. , After the spud supported on the horizontally movable support frame is released from the bottom, the support frame is horizontally moved by the horizontal drive means and then the spud is re-bottomed, and then the support frame is moved in the opposite direction. There has been proposed a barge that moves a barge body by moving the barge horizontally without causing an error in the moving distance due to a difference in water depth.

Japanese Patent Laid-Open No. 2012-76738 Japanese Patent Laid-Open No. 2011-42257 Japanese Patent Laid-Open No. 2012-107586 Japanese Patent Laid-Open No. 2012-76622 Japanese Unexamined Patent Publication No. 2016-22783 Japanese Patent Laid-Open No. 2017-44141 Japanese Patent Laid-Open No. 2012-45970 Japanese Patent Laid-Open No. 11-310189

In these situations, the inventor obtained the following three findings. The first finding is that in a deck-elevating work platform (SEP) equipped with a crane or a handling device for vertically moving the superstructure, or with a erection device for tilting the superstructure, Can be carried out in a stable and fixed state, but on the other hand, in order to receive the weight of these devices and to secure the restoration performance of the work pontoons, the work pontoons are enlarged. There is a problem of doing.

The second finding is that in a work platform that is not a deck lifting type, when the upper structure or the joint is moved up and down due to the sinking amount of the work platform due to ballast adjustment, the deck lifting pedestal system, crane or Since no dedicated device is required, the work pontoon has a simple structure and can be prevented from increasing in size. However, on the other hand, it is not possible to suppress the hull movement of the work pontoon due to waves and swells, and it takes too much time to move the work pontoon up and down at a speed of several tens of cm in 10 minutes by ballast adjustment. Therefore, before joining, there is a possibility that there is a possibility of contact between the upper structure and the lower structure mounted on the work pontoon, and after joining, there is a possibility of contact between the work berth and the joined body.

The third finding is that the deck lifting work platform (SEP) has the function to move the work platform up and down by the deck lifting pedestal system, and also the mobile (walking) spud. If equipped, it can be moved horizontally. Therefore, in the work of lowering the upper structure and the work of joining the upper structure and the lower structure, if the work platform is moved up and down at a speed of several tens of cm in 1 minute by the deck lifting pedestal system, It is possible to raise and lower the superstructure mounted on the work pontoon without using a dedicated device or quicker than ballast adjustment, and to separate the work pontoon from the joined structure of the superstructure and the substructure. It is possible to solve the above problems.

The present invention has been made in view of such a situation, and an object thereof is to use an upper structure that is assembled and integrated on land and transported by a work table ship by using a hanging facility such as a large crane. Of the offshore structure that can be moved up and down faster without adjusting the draft of the work table by ballast adjustment, and in a short time and safely, the upper structure can be joined to the lower structure located in the installation area. To provide a construction method and a work pontoon.

The method for constructing an offshore structure of the present invention to achieve the above-mentioned object is a manufacturing process in which an offshore structure is divided into an upper structure and a lower structure, and the lower structure is installed in a water area. An installation step of transporting and installing, a carrying step of mounting the upper structure on a work pontoon and carrying it to the installation water area, and a superstructure mounted on the work berth by moving the work berth A moving step of moving to an upper portion of the lower structure that is installed in advance, and by lowering the spud of the deck lifting system provided in the work platform to the bottom, the work platform is While floating on the surface of the water while receiving the buoyancy of the hull, or lifted above the surface of the water, the bottoming step of supporting the installation water area and the spud of the deck lifting system equipped on the work platform Spud to raise and lower A descending step of lowering a part or all of the work platform ship by a descending operation to lower the upper structure mounted on the work platform ship onto the lower structure; and the upper structure. A joining step of joining and integrating with the lower structure to form a joined body of the upper structure and the lower structure; and separating the work platform from the joined body of the upper structure and the lower structure. The method for constructing an offshore structure, comprising:

According to this method, in comparison with a work platform equipped with a conventional deck lifting system and a crane, the lowering of the upper structure mounted on the work platform during the lowering process can be performed with the spud of the deck lifting system. Since it is performed by the spud lifting operation used, it is not necessary to use the crane of the crane ship, the crane mounted on the work pontoon, and the handling device for moving the upper structure up and down, and equipping the work pontoon with these. It is possible to avoid an increase in the size of the work pontoon caused by this.

In addition, in the method of lowering the upper structure mounted on the work table by this spud lifting operation, the work table is raised by the spud as compared to the case where the upper structure is lowered only by adjusting the ballast of the work table. Since the hull of the work pontoon is fixed to the water surface or fixed above the water surface, the movement of the hull of the work pontoon due to disturbances such as waves, humming, wind and tidal current can be suppressed, or their influence can be avoided.

Furthermore, since the descending speed and ascending speed of the spud are higher than the sinking speed and the ascending speed of the work table due to the increase or decrease of the ballast water of the work table, the work table and The mounted upper structure can be dropped onto the lower structure. Therefore, the working time in the lowering process can be shortened.

Therefore, the time during which there is a possibility of collision between the upper structure and the lower structure due to the movement of the hull of the work pontoon due to disturbances such as wind and tidal current can be significantly reduced. By restraining or avoiding the movement of the hull and speeding up the descent of the work pontoon, the possibility of contact between the upper structure and the lower structure mounted on the work pontoon before joining and the work after joining The possibility of contact between the pontoon and the joint can be significantly reduced.

In the method for constructing the above-mentioned offshore structure, including a position adjusting step after the bottoming step, and in the position adjusting step, a work platform ship is operated by a spud moving operation using a spud of the walking type deck lifting system. By moving the position in the horizontal direction, it is configured to align the lower joint portion of the upper structure mounted on the work platform and the upper joint portion of the lower structure, The following effects can be achieved.

According to this adjusting step, when a walkable deck elevating system capable of moving in the horizontal direction is provided, the spud moving operation moves the work pontoon in the horizontal direction such as the front-rear direction and the left-right direction. Therefore, it is not necessary to equip another device or system for alignment. Therefore, it is possible to suppress an increase in the size of the work pontoon caused by mounting the positioning device on the work pontoon.

In the construction method of the above-mentioned offshore structure, the detaching step raises or lowers a portion on which the upper structure of the work pontoon is mounted by a spud lifting operation using a spud of the deck lifting system. Thus, the following effects can be achieved by including the vertical separation step of separating the work platform ship from the joined body in the vertical direction.

According to this vertical disengagement step, the work platform is moved in the vertical direction by the spud lifting operation, so that the work platform is removed from the joint more quickly than the draft adjustment of the work platform by ballast adjustment. be able to.

In the method for constructing an offshore structure described above, in the detaching step, the work pontoons are moved horizontally by a spud movement operation using a spud of the walking type deck lifting system. The following effects can be achieved by including a horizontal separating step of separating the above from the joined body in the horizontal direction.

According to this horizontal disengagement process, in the case where a horizontally movable walkable deck elevating system is provided, the work paddle is moved in the horizontal direction such as the front-rear direction and the left-right direction by the spud movement operation. This eliminates the need to equip any other device or system for this horizontal disengagement. Therefore, it is possible to suppress an increase in the size of the work pontoon caused by mounting the horizontal separation device on the work pontoon. In addition, the work platform ship can be quickly removed from the joined body by the spud movement operation of the deck lifting system.

And, the work pontoon for achieving the above-mentioned purpose is provided with a mounting portion for mounting an upper structure of an offshore structure to be transported and installed in an installation water area, and a spud of a deck elevating system for elevating the hull. In the work platform, the loading site tilting mechanism that tilts the loading site with respect to the hull of the work platform is provided.

According to this configuration, the work pontoon hulls of the work pontoon when the superstructure is mounted, the superstructure is lowered, and the work pontoon is detached from the joined structure of the upper structure and the lower structure. When the posture is such as bow trim or stern trim, the mounting part for mounting the upper structure does not have the same inclination as the hull posture, and it can take a posture suitable for the work at that time, such as horizontal, Since it is possible to maintain the inclination of the structure and the parallelism between the lower part of the upper structure and the upper part of the lower structure, it is possible to improve work efficiency and safety during work.

According to the method of constructing an offshore structure and the work pontoon of the present invention, the upper structure assembled and integrated on land and transported by the work pontoon can be used without using a hanging facility such as a large crane. In addition, it can move up and down more quickly than adjusting the draft of the work pontoon by ballast adjustment, and can join the upper structure to the lower structure arranged in the installation water area in a short time and safely.

FIG. 1 is a plan view schematically showing the configuration of an SEP type work pontoon used in the method for constructing an offshore structure according to the first embodiment of the present invention. FIG. 2 is a side view schematically showing the configuration of the half SEP work pontoon ship of FIG. 1, and is a view showing a state in which the spud is bottomed. FIG. 3 is a side view schematically showing the configuration of the full SEP work platform ship of FIG. 1, and is a view showing a state in which the spud is bottomed. FIG. 4: is a figure which shows a part of structure of the construction method of the offshore structure of embodiment which concerns on this invention, and is a figure which shows a manufacturing process, an installation process, and a transportation process. FIG. 5: is a figure which shows a part of structure of the construction method of the offshore structure of FIG. 4, and is a figure which shows a moving process, a bottoming process, and a descent process. FIG. 6 is a diagram showing a part of the configuration of the method for constructing an offshore structure in FIG. 4, and is a diagram showing a joining process, a detaching process, and a return process. FIG. 7: is a figure which shows the state which is approaching the work berth in the state which raised and stored the spud to the quay with an upper structure by the approach method in the mounting process of a conveyance process. FIG. 8 is a diagram for explaining a second approaching method by a spud moving operation, which is an approaching method in the mounting step of the carrying step. FIG. 9 is a diagram showing a state in which the fork portion is inserted under the upper structure in a state where the spud is raised and stored by the approaching method in the mounting step of the transportation step. FIG. 10: is a figure for demonstrating the 2nd scooping method by a spud raising / lowering operation by the scooping method in the mounting process of a conveyance process. FIG. 11: is a figure which shows the state which the work pontoon which mounts an upper structure on the fork part raises a spud, stores it, and is sailing in the navigation process of a conveyance process. FIG. 12: is a figure which shows the state which made the work pontoon carrying the upper structure on the fork part approach the lower structure installed beforehand in the movement process. FIG. 13 shows a state in which the position of the upper structure mounted on the work pontoon is adjusted to the position of the lower structure by the operation of the multi-point mooring winch by the mooring adjustment method in the movement adjusting process of the moving process. FIG. FIG. 14 shows a state in which, in the movement adjusting process of the moving process, the position of the upper structure mounted on the work pontoon is adjusted to the position of the lower structure by the operation of the thruster or the like of the DPS system by the automatic position maintaining method. FIG. FIG. 15 is a diagram showing a state in which the pad of the work pontoon is lowered and bottomed to support the work pontoon in the installation water area in the half SEP state in the bottoming step. FIG. 16 is a diagram showing a state in which the pad of the work pontoon is lowered and bottomed to support the work pontoon in the installation water area in the full SEP state in the bottoming step. FIG. 17: is a figure which shows the state which is moving the work pontoon horizontally by a spud movement operation in the position adjustment process of a bottoming process. FIG. 18 shows a state in which both the front and rear spuds are simultaneously raised by the first descending method by the spud elevating operation in the descending step and the joining step, and the upper structure is descended together with the hull onto the lower structure. FIG. FIG. 19 is a diagram showing a state in which the spud on the bow side is lowered, the bow is lifted and the stern is lowered, and the upper structure is lowered onto the lower structure in the descending step and the joining step. FIG. 20 is a diagram showing a state in which, in the descending step and the joining step, the spud on the stern side is raised, the stern is lowered and the bow is raised, and the upper structure is lowered onto the lower structure. FIG. 21 is a view showing an upper release method of the vertical release step, in which the spuds on the front and rear sides are lowered to raise the hull, and the work platform ship is spaced upward from the joined structure of the upper structure and the lower structure. It is a figure which shows the state which has been. FIG. 22 shows an upward disengagement method in the vertical disengagement step, in which the spud on the bow side is raised, the bow is raised and the stern is lowered, and the work platform is moved upward from the joined structure of the upper structure and the lower structure. It is a figure which shows the state which is made to space apart. FIG. 23 is a view showing an upward disengagement method in the vertical disengagement step, in which the spud on the stern side is raised, the bow is lowered and the stern is raised, and the work platform is lifted from the joined structure of the upper structure and the lower structure. It is a figure showing the state where it has separated in the direction. FIG. 24 shows that in the horizontal disengagement process, the stern side spud is moved forward by the kick mechanism of the bow side spud to move the work platform horizontally from the joined structure of the upper structure and the lower structure. It is a figure showing the state where it has separated in the direction. FIG. 25 is a diagram showing a state in which the work pontoon is sailing while raising and retracting the spud in order to return from the installation water area in the returning process. FIG. 26 is a diagram showing the relationship between the fork portion, the upper structure, and the lower structure before joining in the joining process when the upper structure is connected to the upper side of the fork portion. FIG. 27 is a diagram showing a relationship between the fork part, the upper structure, and the lower structure after the joining in the downward separating method when the upper structure is connected to the upper side of the fork part. FIG. 28 is a diagram showing a relationship between the fork portion, the upper structure, and the lower structure before joining in the joining process when the upper structure is connected to the lower side of the fork portion. FIG. 29 is a diagram showing a relationship between the fork part, the upper structure, and the lower structure after joining in the upward separating method when the upper structure is connected to the lower side of the fork part. FIG. 30: is a figure which illustrates the bottom plate of a spud, (a) is a figure which shows a fixed bottom plate, (b) is a figure which shows an open-close type bottom plate. FIG. 31: is a top view which shows typically the structure of the work table ship of SEP type used with the construction method of the offshore structure of the 2nd Embodiment which concerns on this invention. 32 is a side view schematically showing the configuration of the half SEP work pontoon ship of FIG. 31, and is a view showing a state in which the spud is bottomed. 33 is a side view schematically showing the configuration of the full SEP work pontoon ship of FIG. 31, and is a view showing a state in which the spud is bottomed. FIG. 34 is a perspective view schematically showing the configuration of the first movable mounting table. FIG. 35: is a top view which shows typically the structure of the work table ship of the SEP type used with the construction method of the offshore structure of the 3rd Embodiment which concerns on this invention. FIG. 36 is a side view schematically showing the configuration of the half SEP work platform ship shown in FIG. 35, and is a view showing a state in which the spud is bottomed. FIG. 37 is a side view schematically showing the configuration of the full SEP work platform ship of FIG. 35, and is a view showing a state in which the spud is bottomed. FIG. 38 is a plan view schematically showing the configuration of an SEP type work pontoon used in the method for constructing an offshore structure according to the fourth embodiment of the present invention. FIG. 39 is a side view schematically showing the configuration of the half SEP work platform ship of FIG. 38, and is a view showing a state in which the spud is bottomed. FIG. 40 is a side view schematically showing the configuration of the full SEP work table vessel of FIG. 38, and is a view showing a state in which the spud is bottomed.

Hereinafter, a method of constructing an offshore structure according to an embodiment of the present invention will be described with reference to the drawings.

First, a work pontoon used in the method for constructing an offshore structure according to the first embodiment of the present invention will be described. As shown in FIGS. 1 to 3, the work pontoons 1A and 1B are a type of work pontoons called SEP (Self Elevating Platform) or a jack-up ship. Several (three in this embodiment) spuds (legs, lift legs) 20A and 20B arranged on the work pontoons 1A and 1B called platforms, and the spuds 20A and 20B are lowered and their tips (bottom part). ) Is set on the water bottom (sea bottom) B to lift the hull 2 and is provided with lifting leg lifting systems (jack up systems) 21A and 21B.

The work pontoons 1A and 1B are displacement-type work pontoons that obtain buoyancy when the lower part of the hull 2 sinks below the water surface. However, in the half SEP work pontoon 1A, as shown in FIG. By lowering the spuds 20A and 20B to reach the bottom by the deck elevating type systems 21A and 21B, a part of the load of the work pontoon 1A is borne by the spuds 20A and 20B. That is, when performing various operations, the work table boat 1A is raised by using the supporting force of the spuds 20A and 20B and the buoyancy of the hull 2 together, but the hull 2 of the hull 2 can be lifted even when the jacking up of the spuds 20A and 20B is completed. The hull 2 is floated on the water surface S without raising the whole body above the water surface S. In the case of this half SEP, the spuds 20A and 20B are not large-capacity ones capable of lifting all of the dead weight and the deadweight of the work pontoon 1A like the full SEP, but are used for a dredging pontoon. , It is sufficient that the buoyancy is partially supplemented to stabilize the hull.

On the other hand, in the work table 1B of full SEP, as shown in FIG. 3, the deck lifting systems 21A and 21B lower the spuds 20A and 20B to reach the bottom, and lift the work table 1B above the water surface S. As a result, the spuds 20A and 20B bear the entire load of the work pontoon 1B. That is, when performing various operations, the entire work pontoon 1B is raised by the spuds 20A and 20B to a height above the water surface S at which waves cannot reach, so that the influence of the waves on the water surface S and the influence of the tidal current may increase. It should not reach the 1B hull. The full SEP work pontoon 1B generally works under severer sea and weather conditions than the half SEP.

1 to 3, in the decks (deck) 3 of the hull 2, the work pontoons 1A and 1B have, on the stern side, a pair of arm-like structures that project rearward on both sides of the stern ( The protrusion) 4a is formed. As a result, the U-shaped fork portion 4 having the recess A is provided between the pair of protrusions 4a in plan view.

The fork portion 4 is a mounting portion for mounting the upper structure 41 of the offshore structure 40 that is transported and installed in the installation water area. It is preferable that the fork portion 4 as the mounting portion is provided with a mounting portion tilting mechanism for tilting the fork portion 4 with respect to the hull 2 of the work pontoon 1A, 1B. As the mounting portion tilting mechanism, the fork part 4 is connected to the hull 2 by a hinge structure so that the stern side of the fork part 4 moves up and down around this hinge and tilts in the vicinity of the bow trim and the stern trim. To configure. This inclination can be easily configured by providing an inclination sensor on the fork portion 4 and controlling the expansion and contraction of the hydraulic cylinder that supports the fork portion 4 by the output thereof. This structure can be realized by a structure similar to that of the ramp way of a car ferry or a landing craft.

According to this configuration, as described below, the work pontoons 1A and 1B mount the upper structure 41, lower the upper structure 41, and work from the joined body 40 of the upper structure 41 and the lower structure 42. When the berths of the work pontoons 1A and 1B become the bow trim and the stern trim when the pontoons 1A and 1B are disengaged, the mounting portion (fork portion 4) for mounting the upper structure 41 is Since the posture is not the same as the posture, and the posture suitable for the work at that time can be taken such as horizontal, the inclination of the upper structure 41, the bottom surface of the lower portion 41 d of the upper structure 41 and the upper portion 42 of the lower structure 42. Since it is possible to maintain the relation of mutual postures such as parallel between the upper surface and the upper surface, it is possible to improve work efficiency and safety during work.

Also, on the bow side, a superstructure 5 as a bridge and a living area is installed. It should be noted that although propelling systems such as a propeller and a rudder for self-propelling are mounted as needed, these propulsion systems are not shown except for FIG.

These work pontoons 1A, 1B are walking type work pontoons that can move the work pontoons 1A, 1B as if they walk on the seabed B using the spuds 20A, 20B. It is preferable that the spuds 20A and 20B are provided with two or more legs, more preferably three or more legs, and further, the spuds 20A and 20B are preferably provided separately in the front, rear, left and right of the work pontoons 1A, 1B. Here, a pair of left and right fixed-type stern-side spuds 20A are provided near each of the stern-side fork portions 4, and a kick-type spud 20B is provided at the center of the bow side.

This fixed-type spud 20A has relative swing and horizontal freedom between the spud 20A and the work pontoons 1A and 1B when the amount of protrusion of the spud 20A to the lower part of the work pontoons 1A and 1B is fixed. The degree is restricted. On the other hand, in the kick type spud 20B, relative swinging about the pin is allowed in a state where the amount of protrusion of the spud 20B to the lower part of the work platform 1A, 1B is fixed by the support by a horizontal pin, By pushing and pulling a portion of the spud 20B above the pin in a horizontal direction relative to the work platform 1A, 1B by a hydraulic cylinder or the like, as shown in FIGS. 20B is inclined like a pendulum.

In these work pontoons 1A and 1B, the work pontoons using the kick type spuds 20B are used, but other walk-type work pontoons may be used. For example, the relative swing of the spuds 20A and 20B is not allowed and remains vertical, but by sliding the spuds 20A and 20B horizontally with respect to the work pontoons 1A and 1B by the hydraulic cylinder, the work pontoons 1A 1B may be movable. As described above, since the spuds 20A and 20B have the walking function, the horizontal position of the work pontoons 1A and 1B can be finely adjusted by the spud movement operation.

At the bottom of these spuds 20A and 20B, a bottom plate that is used as necessary in consideration of the geological features of the seabed is equipped. This bottom plate has a structure for receiving the force applied to the spuds 20A and 20B. As shown in FIG. 30, there is an openable-closed bottom plate 22b in addition to the fixed bottom plate 22a. The openable bottom plate 22b is widely opened to cope with soft ground such as loose sand or cohesive soil, or the bottom plate 22b is flipped up to invalidate the support by the bottom plate 22b, thereby sharply forming the tower tip 22c. It is constructed so that it can be stabbed in solid ground.

Then, as a descending method by this spud raising / lowering operation, as shown in FIG. 18, the front and rear spuds 20A and 20B are simultaneously raised to lower the work platform 1A while maintaining the attitude of the hull 2. As shown in FIG. 20, the descending method and the second descending method of descending only the bow side spud 20B, raising the bow and lowering the stern, and descending the stern side of the work platform 1A are shown in FIG. As shown, the third descending method, which raises only the stern side spud 20A, lowers the stern and raises the bow, and descends the stern side of the work platform ship 1A, and the second and third descending methods. There is a fourth descending method which uses the above together.

As shown in FIGS. 10, 15, 16 and 21, the method of raising by this spud lifting operation is to lower the front and rear spuds 20A and 20B at the same time while maintaining the attitude of the hull 2. As shown in FIG. 22, only the first spud 20B on the bow side is raised, the bow is lowered and the stern is raised, and the stern side of the work pontoon 1A is raised. A second raising method for raising, as shown in FIG. 23, a third raising method for lowering only the stern side spud 20A, raising the stern and lowering the bow, and raising the stern side of the work pontoon 1A. , And there is a fourth raising method that uses the second and third raising methods together.
Then, in the horizontal movement method by the spud movement operation, as shown in FIGS. 8, 17, and 24, the spud 20A on the stern side is raised and the spud 20B is moved by the kick mechanism of the spud 20B on the bow side. By tilting like a pendulum and kicking the seabed B at its tip, the work pontoons 1A and 1B are pushed and pulled relatively horizontally, thereby moving the work pontoons 1A and 1B horizontally. .

Also equipped with a multi-point mooring winch system as shown in FIG. 13 or an automatic ship position holding system (DPS) as shown in FIG. When equipped with these, they can be used not only in offshore wind power facilities but also in various projects.

Note that in the following description, the half SEP work platform ship 1A will be mainly described. However, although the height relationship between the hull 2 and the water surface S is different, the same operation can be performed with the full SEP work platform 1B. In the above description, the pair of arm-shaped structures 4a are provided at the stern of the work pontoons 1A and 1B. However, if there is a structure for supporting the upper structure 41, the pair of arm-shaped structures 4a is not necessary. The supporting portion on which the upper structure 41 is mounted may be, for example, the bow or the side of the boat, instead of the stern. In that case, the fixed spud 20A is arranged at a position close to the support portion, and the kick spud 20B is arranged at a position far from the support portion.

Next, a method of constructing an offshore structure according to the first embodiment of the present invention will be described. In this construction method for an offshore structure, the manufacturing process, the installation process, and the transportation process shown in FIG. 4, the moving process, the bottoming process, the position adjusting process, the descending process shown in FIG. 5, the joining process and the detachment shown in FIG. It includes some or all of various processes such as the process and the return process.

First, the manufacturing process, installation process, and transportation process shown in FIG. 4 will be described. The manufacturing process is a process of dividing the offshore structure 40 into an upper structure 41 and a lower structure 42 for manufacturing. As shown in FIG. 7, the upper structure 41 is generally composed of a tower 41a, a nacelle 41b, a blade 41c and the like. On the other hand, here, as the lower structure 42, as shown in FIG. 12, a landing type monopile is adopted.

In addition to this monopile, there are various types of platform such as gravity type, jacket basic type, developed type tripile, hybrid type tripod, etc. in addition to the basic type of gravity type, jacket. These substructures are provided so as to be self-supporting on a foundation installed on the water bottom of the installation site, and the tops thereof are provided near the water surface S (above or below the water surface S). .. Further, as the floating type substructure, there is a columnar tower structure moored by anchors and mooring lines, as in the case of a spar type offshore structure. This is provided so that it floats in an upright state like a fishing float and the top is near the water surface S (above or below the water surface S).

Also, the installation process is a process of transporting and installing the lower structure 42 in the installation water area. The lower structure 42 (here, a monopile) formed of various types of mounting bases such as a landing type monopile, a gravity type, and a jacket is selected according to the water bottom ground where the offshore structure 40 is installed, and is a large hydraulic hammer. It is installed at the installation location of the offshore structure 40 by using a large work boat, a large carrier ship, or the like.

The carrying step is a step of carrying the superstructure 41 on the work pontoon 1A and carrying it to the installation water area. However, as shown in FIGS. 7 to 10, the superstructure 41 approaches the quay C and the superstructure is carried by the quay C. This includes the step of mounting 41 on the work pontoon 1A and the step of navigating the work pontoon 1A with the upper structure 41 mounted therein to the installation water area as shown in FIG.

In the mounting process, a manufacturing plant or a crane installed on the quay is used to assemble a tower 41a, a nacelle 41b, a blade 41c, and the like to form an integrated upper structure 41, as shown in FIG. Prepare in advance on the pedestal Cb of the quay C. In this mounting step, the work platform 1A is approached to the upper structure 41 placed on the pedestal Cb of the quay C, and the fork portion 4 is inserted below the lower part 41d of the upper structure 41. After this insertion, the scooping method is used in which the fork part 4 is raised to scoop the upper structure 41 by the fork part 4 and the upper structure 41 is loaded on the work platform 1A.

Regarding the approaching method, as a first approaching method, as shown in FIG. 7, the pads 20A and 20B are raised and stored, and the stern fork portion 4 is lowered by ballast operation of the work pontoon 1A. Then, the work table boat 1A is brought closer to the quay C by using the propulsion force of the work table boat 1A or the propulsion force of another ship such as a tug boat.

As a second approaching method, as shown in FIG. 8, the spuds 20A and 20B are lowered by the spud lifting operation to reach the bottom, and the work paddle 1A is operated by the spud moving operation using these spuds 20A and 20B. The fork part 4 is put under the lower part 41d of the upper structure 41 by using the spud moving method of moving the fork to the side of the quay C.

Furthermore, as a third approaching method, by using the tide, before and after the ebb tide, the work platform 1A is moved to the quay C side and the fork part 4 is put under the lower part 41d of the upper structure 41. .. There is also a method of moving the work pontoon 1A to the quay C side by adjusting the length of the mooring line provided between the work pontoon 1A and the quay.

Next, as for the scooping method, as a first scooping method, as shown in FIG. 9, the fork part 4 in the stern is lowered by the ballast operation of the work pontoon ship 1A, and the fork part 4 is moved to the upper structure. The lower part 41d of the upper structure 41 is put under the lower part 41d of the upper structure 41, and then the fork part 4 is lifted by the ballast operation of the working structure 1A to scoop up the lower part 41d of the upper structure 41 to move the upper structure 41 to the work structure 1A. It is loaded on the fork part 4 of.

Further, as a second scooping method, as shown in FIG. 8, the spuds 20A and 20B are lowered to reach the bottom and approached by the second approaching method, and thereafter, as shown in FIG. It is also possible to use a method of raising the fork portion 4 of the work pontoon ship 1A by a spud lifting operation using the spuds 20A and 20B.

Although the front and rear spuds 20A and 20B are lowered in the same manner in FIG. 10, only one of the spuds may be moved up and down to raise the stern. In the case of this spud raising / lowering operation, it is possible to reduce the influence of the hull movement of the work pontoon 1A, and moreover, the upper structure 41 can be scooped up by the fork portion 4 more quickly than the ballast operation. In this case, in the case where the fork portion 4 is provided with the mounting portion tilting mechanism, the tilting of the fork portion 4 is kept in alignment with the quay C with respect to the change in the attitude of the hull, so that the loading work can be performed. It is preferred to avoid tilting the superstructure 41 at.

In addition, as the third scooping method, when the tide is high, the fork portion 4 rises as the hull 2 rises. At that time, the upper structure 41 is scooped up by the fork portion 4 so that the work platform ship You may load in 1A.

Corresponding these first, second, and third approaching methods and the first, second, and third scooping methods to the state of the sea condition, the weather, and the tide at the time of the approaching work and the loading work, It is preferred to use each alone or in combination.

In the navigation process, as shown in FIG. 11, in the work pontoon ship 1A, the spuds 20A and 20B are separated from the water bottom B as needed, and the lowest parts of the spuds 20A and 20B are near the water surface S. The spuds 20A and 20B are raised until they reach the state where they are stored in the work pontoon ship 1A. In this navigation, if the work pontoon ship 1A is equipped with a propulsion system so that it can self-propell, it will use the propulsion system to self-propell, but when it is towed by a tugboat, etc., it will depend on the propulsion system of another ship. Sail.

Next, the moving process, bottoming process, and descending process shown in FIG. 5 will be described. The moving process is a process after the work pontoon 1A reaches the installation water area by the navigation process, and by moving the work pontoon 1A, the upper structure 41 mounted on the work pontoon 1A is installed in advance as a lower structure. This is a step of moving to the upper portion 42a of 42. In this moving step, as shown in FIG. 12, even when the lower portion 41d and the upper portion 42a of the lower structure 42 are at the same position on the horizontal plane as the lower portion 41d and the upper portion 42a of the lower structure 42, the collision does not occur. As described above, the robot moves while maintaining a certain vertical distance D.

In this moving step, the upper structure 41 and the lower structure 42 are separated by setting the hull trim as a toe (a bow trim with the stern side raised) and raising the stern's fork part 4. It is preferable that the upper structure 41 is moved so as to be positioned on the lower structure 42 while being sufficiently separated from each other in the vertical direction. Even in this case, it is preferable to avoid the inclination of the upper structure 41 by the mounting portion inclination mechanism of the fork portion 4.

In this moving process, instead of levitating the hull 2 due to the decrease of ballast water, the moving process is performed when the tide changes from low tide to high tide by using the tide (tide). By raising the ship 1A, the fork portion 4 carrying the upper structure 41 can be raised.

In this movement, as shown in FIG. 12, in a state where the spuds 20A and 20B are raised and stored, the propulsion force moving method in the floating state in which the spuds are moved by the propulsion system of the own ship or another ship is used. You can Further, similar to the second approaching method in the mounting step shown in FIG. 8, the spuds 20A, 20B are lowered to reach the bottom, and the work platform 1A is moved downward by the spud movement operation using these spuds 20A, 20B. It is also possible to use the spud moving method of moving the structure 42 to the upper portion 42a.

The movement adjustment process is, if necessary, the latter half of the movement process included in the movement process and the process before the bottoming process. In this movement adjusting step, the position of the work pontoon 1A is moved by moving the position of the work pontoon 1A in the front-rear direction and the left-right direction, that is, in the horizontal direction. The position of the work carrier 1A is adjusted so that the upper portion 41d, which is the lower joint portion of the object 41, and the lower portion 42a, which is the upper joint portion of the lower structure 42, are aligned.

The following methods can be used in this movement adjustment process. As a first method, as shown in FIG. 13, a method of using a mooring adjustment method in the case of multi-point mooring moored by an anchoring cable 6b connecting the mooring cable 6a and the anchor is used. In this method, the position of the work table boat 1A is adjusted by adjusting the length and tension of the mooring line 6a and the anchor line 6b by operating the marine vessel maneuvering winch or the anchoring device equipped on the work table boat 1A. And hold the position at the adjusted position.

In addition, as a second method of the movement adjusting step, as shown in FIG. 14, an automatic ship position holding system (DPS) using an azimuth thruster 7a, a side thruster 7b, etc. is equipped, and the position of the work carrier 1A is adjusted. Adjust and hold in place after the adjustment.

In addition, in a case where a plurality of upper structures 41 are continuously installed on the respective lower structures 42 in the installation water area, the spuds 20A and 20B that have dropped are not raised and stored one by one, Similar to the second approaching method in the mounting step shown in FIG. 8, the third method of moving by a spud moving operation can also be used.

In the bottoming step, the work pontoons 1A were floated on the water surface S while receiving the buoyancy of the hull by lowering the spuds 20A and 20B of the deck lifting system provided on the work pontoons 1A to reach the bottom. In this state, or in a state of being lifted above the water surface S, it is a step of supporting the installation water area.

In this bottoming step, as shown in FIG. 15, when the work pontoon 1A is a half SEP, the spuds 20A and 20B are bottomed on the water bottom B, but the spuds 20A and 20B are further lowered to form the hull 2 It floats on the water surface S while receiving the buoyancy. When working in this floating state, the spuds 20A and 20B are set on the bottom of the water B, and a part of the weight of the work table ship 1A is borne on the bottom of the water B via the spuds 20A and 20B. Since the work pontoon 1A is in a state of being erected on the water bottom B while floating, it is possible to suppress the periodic hull movement of the work pontoon 1A due to waves and swells.

However, during work, the weight added to the hull changes due to the tide difference and movement of the upper structure 41 to the lower structure 42, which causes changes in draft and buoyancy. Further, since the hull 2 is in a floating state, it is not possible to completely prevent the work pontoon 1A from swaying due to waves or wind.

On the other hand, in this bottoming process, as shown in FIG. 16, when the work pontoon 1B is full SEP, even if the spuds 20A and 20B land on the water bottom B, the spuds 20A and 20B are further lowered and the work pontoon 1B is lowered. It is in a state of being lifted so as to be completely above the water surface S. Then, when working, the entire hull 2 of the work pontoon 1B is maintained at a height above the water surface S and out of reach of the waves, and the influence of the waves on the water surface S and the influence of the tidal current are influenced by the work pontoon 1B. Do not reach the hull 2 of. As a result, vertical movement of the work pontoon ship 1B and hull movement can be significantly suppressed.

In the position adjusting step, as shown in FIG. 17, after the bottoming step described above, the work platform 1A is operated by a spud moving operation using the spuds 20A and 20B of a walking type deck elevating system that is horizontally movable. Position of the lower joint (upper) 41d of the upper structure 41 mounted on the work platform 1A and the upper joint (upper) 42a of the lower structure 42 by moving the position of Is a step of performing. In this spud movement operation, the stern side spud 20A is raised and the work table boat 1A is horizontally moved by the kick of the bow side spud 20B or the like to perform alignment.

According to this position adjustment step, the work table boat 1A is moved in the horizontal direction such as the front-rear direction and the left-right direction by the spud movement operation of the spuds 20A and 20B, so that other devices and systems for alignment are equipped. There is no need. Therefore, it is possible to suppress an increase in the size of the work pontoon 1A caused by mounting the device for alignment on the work pontoon 1A.

The descending step is carried on the work pontoon 1A by lowering part or all of the work pontoon 1A by a spud raising / lowering operation of raising / lowering the spuds 20A and 20B of the deck lifting system provided on the work pontoon 1A. This is a step of lowering the existing upper structure 41 onto the lower structure 42. By this lowering step, the fork portion 4 is lowered, so that the upper structure 41 and the lower structure 42 are brought into contact with, engaged with, or fitted to each other. As a result, the fork portion 4 and the upper structure 41 can be lowered while suppressing the periodic hull motion due to the waves and swells of the work pontoon 1A, so that the upper structure 41 is efficiently joined to the lower structure 42. can do.

In this descending step, as a first descending method by vertically operating the spud, as shown in FIG. 18, both the front and rear spuds 20A and 20B are simultaneously raised to maintain the attitude of the hull 2 while maintaining the attitude of the hull 2. A method of lowering the fork portion 4 together with 2 can be used. In this case, since the number of spuds 20A and 20B to be operated is three, it is necessary to synchronize with each other in order to avoid the inclination of the hull 2.

As a second descending method, as shown in FIG. 19, only the spud 20A on the bow side is lowered, the bow side is raised and the hull attitude is tilted, and the fork portion 4 on the stern side is lowered. Any method can be used. In this case, since the operated spud 20A is one on the bow side, it is not necessary to synchronize with the other two spuds 20B on the stern side. Then, the influence of the waves on the work pontoon ship 1A can be more surely reduced by adopting "tomoashi" for lifting the bow side. In this case, it is preferable to avoid the inclination of the upper structure 41 by the mounting portion inclination mechanism of the fork portion 4.

Further, in this case, by adjusting the ballast in the work pontoon 1A, the hull 2 can be sunk by the amount of the ballast water corresponding to the weight of the upper structure 41 and the vertical distance desired to be secured after the joint 41 is separated from the joint 41 after joining. It is preferable to load ballast water corresponding to the amount.

Further, as a third descending method, as shown in FIG. 20, only the spud 20B on the stern side is slightly retracted and raised, and the stern side is lowered to incline the hull posture to lower the fork portion 4. The method can be used. In this case, since the two spuds 20B to be operated are on the stern side, it is necessary to synchronize between the two spuds 20B in order to avoid lateral inclination of the hull 2. In this case, it is preferable to avoid the inclination of the upper structure 41 by the mounting portion inclination mechanism of the fork portion 4.

Further, in contrast to these descending methods, when the work pontoon 1A is a semi-SEP, it is preferable to increase the ballast water so that the hull 2 can easily descend. By performing the descending step when shifting to, it is possible to descend the work platform 1A without depending on the ballast adjustment. Therefore, the burden of auxiliary ballast adjustment for lowering the hull 2 and changing the hull attitude can be reduced, and the lowering process can be performed more quickly.

According to this descending process, the lowering of the upper structure 41 mounted on the work platform 1A is performed by the spud 20A of the deck lifting system, compared to the work platform equipped with the conventional deck lifting system and the crane. Since it is carried out by the spud lifting operation using 20B, it is not necessary to use a crane of a crane ship, a crane mounted on a work table ship, and a handling device for moving up and down an upper structure. It is possible to avoid an increase in the size of the work pontoon caused by the equipment.

Further, in the method of lowering the upper structure 41 mounted on the work platform 1A by this spud raising / lowering operation, the work platform 1A is lowered as compared with the case where the upper structure 41 is lowered only by adjusting the ballast of the work platform 1A. Since the hull 2 of the work pontoon 1A is fixed to the water surface S or fixed above the water surface S by being raised by the spuds 20A and 20B, the hull of the work pontoon 1A due to disturbances such as waves, humming, wind and tidal currents. It is possible to suppress the movements of No. 2 or avoid their influence.

Furthermore, since the descending speed and the ascending speed of the spuds 20A and 20B are about 10 times higher than the sinking speed and the ascending speed of the working ship 1A due to the increase or decrease of the ballast water of the working ship 1A, the descent process is quick. In addition, the work platform 1A and the upper structure 41 mounted on the work carrier 1A can be lowered onto the lower structure 42. Therefore, the working time in the lowering process can be shortened. For example, when increasing or decreasing the ballast water, it may take about 10 minutes or more to adjust the ballast just to raise or lower the front end or the rear end of the hull by several tens of centimeters. It may be 0.4 m / min.

Therefore, the time during which there is a possibility of collision between the upper structure 41 and the lower structure 42 due to the hull motion of the work pontoon 1A due to disturbances such as wind and tidal current can be significantly shortened. By suppressing or avoiding the movement of the hull and speeding up the descent of the work platform 1A, the possibility of contact between the upper structure 41 and the lower structure 42 mounted on the work platform 1A is significantly increased before joining. Can be lowered.

The joining step is a step of joining the upper structure 41 and the lower structure 42 and integrating them to form a joined body 40 of the upper structure 41 and the lower structure 42. In this joining step, both the lower portion 41d of the upper structure 41 and the upper portion 42a of the lower structure 42 are brought into contact with, engaged with, or fitted to each other by the descending step. The lower portion 41d of the upper structure 41 and the upper portion 42a of the lower structure 42 are joined to each other by using a joining member such as bolts and nuts or performing joining work such as welding. After this joining, the connection between the upper structure 41 and the fork portion 4 is released. Also in this joining step, it is preferable to avoid the inclination of the upper structure 41 by the mounting portion inclining mechanism of the fork portion 4 so that the efficiency of the joining operation is improved.

In addition, when there is a possibility that the stern suddenly rises when the connection between the upper structure 41 joined to the lower structure 42 and the fork portion 4 is released, before the joining, if necessary, the upper structure may be released. It is preferable to load ballast water in an amount corresponding to the weight of the object 41 on the rear portion of the hull 2 to prevent the stern from suddenly rising during the removal process. In addition, the load of the upper structure 41 is transferred to the lower structure 42 between the joining and the vertical separation, and the weight of the upper structure 41 is unloaded on the side of the work platform 1A. Therefore, prior to or in parallel with the vertical disengagement process, if necessary, the ballast of the work pontoon ship 1A is set to the medium load state, or the ballast water is transferred to the stern side so that the hull trim is even. It is preferable to adjust the ballast.

In the detaching process, after transferring the load of the upper structure 42 to the lower structure 41, the swing of the work platform 1A is suppressed by the support of the spud, and the upper structure is operated by the spud lifting operation of the deck lifting system. This is a step of separating the work platform 1A from the joined body 40 of 41 and the lower structure 42. In this disengagement step, the horizontal disengagement step is performed after performing the up-down direction disassociation step. However, if it is possible to perform in parallel, it is possible to shorten the disassociation step time by performing them in parallel. Therefore, it is more preferable.

In the vertical separation process of this separation process, the part of the work platform 1A on which the upper structure 41 is mounted is further lowered by the spud lifting operation using the spuds 20A and 20B of the deck lifting system, or conversely. It is a step of vertically moving the work pontoon 1A away from the joined body 40 by raising it. In this vertical separation step, the weight equivalent to the weight of the upper structure 42 that will not be added to the work platform 1A after joining and the weight equivalent to the sinking or floating of the hull 2 by the vertical distance that is desired to be secured after the separation. It is preferred to load a combined weight of ballast water.

More specifically, as shown in FIGS. 26 and 27, the upper surface of the fork portion 4 and the lower surface of the lower portion 41d of the upper structure 41 (cross-hatching portion) are connected and transported, and the fork portion 4 is lowered. Then, the vertical distance D1 is reduced, and the lower surface of the lower portion 41d of the upper structure 41 is brought into contact with the upper surface of the upper portion 42a of the lower structure 42 (cross hatching portion), and the upper structure 41 and the lower structure 42 are contacted. Are joined together to form a joined body 40. After that, the connection between the upper surface of the fork portion 4 and the lower surface of the lower portion 41d of the upper structure 41 is released, and the fork portion 4 is lowered, thereby increasing the vertical distance D2 and joining the work platform 1A. Remove from body 40. In this case, the downward separating process is performed.

Alternatively, as shown in FIGS. 28 and 29, the lower surface of the fork portion 4 and the upper surface of the lower portion 41d of the upper structure 41 (cross-hatched portion) are connected and transported, and the fork portion 4 is lowered. The vertical distance D3 is reduced, and the lower surface of the lower portion 41d of the upper structure 41 is brought into contact with the upper surface of the upper portion 42a of the lower structure 42 (cross hatching portion) to join the upper structure 41 and the lower structure 42. The joined body 40 is formed. Then, the lower surface of the fork part 4 and the upper surface of the lower part 41d of the upper structure 41 are disconnected, and the fork part 4 is lifted to increase the vertical distance D4 and join the work pontoon 1A. Remove from body 40. In this case, the upward separation process is performed.

Then, in this vertical disengagement step, there are a downward disengagement in which the fork portion 4 moves downward and an upward disengagement in which the fork portion 4 moves upward. As the first downward disengagement method by the spud lifting operation, similar to the first descending method of the descending step shown in FIG. 18, both the front and rear spuds 20A and 20B are simultaneously raised to maintain the attitude of the hull 2. However, a method of lowering the fork portion 4 together with the hull 2 can be used. In this case, since the number of spuds 20A and 20B to be operated is three, it is necessary to synchronize with each other in order to avoid the inclination of the hull 2.

Further, as the second downward separating method, as in the second descending method of the descending step shown in FIG. 19, only the spud 20A on the bow side is lowered and the bow side is raised to incline the hull attitude. Therefore, a method of lowering the fork portion 4 on the stern side can be used.

As the third downward disengagement method, similarly to the third descending method in the descending step shown in FIG. 20, only the spud 20B on the stern side is raised and the stern side is lowered to incline the hull attitude. Therefore, a method of lowering the fork portion 4 can be used. That is, the stern side spud 20A is further retracted and the fork portion 4 is lowered, whereby the upper part structure 41 of the joined body 40 and the fork portion 4 are separated in the vertical direction. In these cases, two spuds 20B to be operated are provided on the stern side, so that synchronization between the two spuds 20B is required to avoid lateral inclination of the hull 2.

In the first upward disengagement method in the up-and-down disengagement step, as shown in FIG. 21, both front and rear spuds 20A and 20B are simultaneously lowered to maintain the attitude of the hull 2 while maintaining the attitude of the hull 2. At the same time, a method of raising the fork portion 4 can be used.

As a second upward disengagement method, as shown in FIG. 22, by raising only the spud 20A on the bow side and lowering the bow side to tilt the hull posture, the fork portion 4 on the stern side is Can be used. That is, by returning the spud 20A on the bow side and lifting the fork portion 4, the joined body 40 and the fork portion 4 are separated from each other in the vertical direction. In these cases, since the spud 20A to be operated is one on the bow side, it is not necessary to synchronize with the other two spuds 20B on the stern side.

In addition, as a third upward disengagement method, as shown in FIG. 23, only the spud 20B on the stern side is lowered, the stern side is raised, and the hull attitude is tilted to raise the fork portion 4. Any method can be used. That is, the spud 20A on the stern side is further extended to raise the fork portion 4 to separate the joined body 40 and the fork portion 4 in the vertical direction.

According to these vertical disengagement steps, the work table boat 1A is moved in the vertical direction by the spud lifting operation. Therefore, as compared with the draft adjustment of the work table boat 1A by ballast adjustment, the work table boat 1A can be quickly moved from the joint body 40 to the work platform table. It is possible to leave the ship 1A.

Further, with respect to these vertical separation methods, when the work pontoon 1A is a semi-SEP, it is preferable to decrease or increase the ballast water so that the hull 2 can easily move up or down, but the tide is used. Then, at the time of transition from high tide to low tide, or conversely at the time of transition from low tide to high tide, the work platform 1A can be raised or lifted by performing the vertical separation process without depending on ballast adjustment. Can be lowered. Therefore, the burden of auxiliary ballast adjustment for lowering the hull 2 or changing the hull attitude can be reduced, and the vertical disengagement process can be performed more quickly. In the vertical disengagement step, the vertical distances D2 and D4 between the joined body 40 and the fork portion 4 of the work platform 1A are adjusted by combining the spud lifting operation and the tidal difference and ballast adjustment as necessary.

In the horizontal separation step of this separation step, the work platform 1A is moved in the horizontal direction by a spud movement operation using the spuds 20A and 20B of the walk-type deck lifting system to join the work platform 1A to the joined body. It is a step of horizontally separating from 40. In this horizontal separation step, the above vertical separation step leaves the installation water area (site sea area) by moving in the horizontal direction after keeping a sufficient distance in the vertical direction.

In the horizontal disengagement step, as a first method, all the spuds 20A and 20B are lifted and a multi-point mooring marine vessel winch is used as in the moving step shown in FIG. You may use the mooring utilization detachment method of detaching 1A from the joined body 40 horizontally. As a second method, similarly to the moving step shown in FIG. 14, all the spuds 20A and 20B are raised to use the own ship's propulsion system such as the azimuth thruster 7a and the side thruster 7b, or the tugboat or the like. The work table ship 1A may be horizontally separated from the joined body 40 by using a propulsion force separation method using the propulsion system of another ship.

Then, as a third method of this horizontal disengagement step, there is a horizontal disengagement method by a spud moving operation. In this method, as shown in FIG. 24, the stern side spud 20A is raised and the bow side spud is operated. By the kick of 20B, the work pontoon 1A is moved in the horizontal direction and is separated from the joined body in the horizontal direction.

According to this horizontal disengagement step, when a horizontally movable walkable deck lifting system is provided, the spud movement operation of the deck lifting system moves the work platform 1A in the front-back direction, left-right direction, etc. Since it can be moved horizontally, it is not necessary to equip another device or system for this horizontal disengagement. Therefore, it is possible to suppress an increase in the size of the work pontoon 1A caused by mounting the device for horizontally separating on the work pontoon 1A. In addition, the work platform 1A can be quickly removed from the joined body 40 by moving the spud of the deck lifting system.

Even in these disengagement steps, in order to make it easier to avoid contact between the joined body 40 and the work platform 1A, the attitude of the fork portion 4 can be easily disengaged by the mounting portion inclination mechanism of the fork portion 4. It is preferable to change or maintain.

The return flight process is a process of returning from the installation water area after the installation work, and as in the return flight process shown in FIG. 5, as shown in FIG. 25, the spuds 20A and 20B are placed in a safe place at the work table 1A. The spuds 20A and 20B are raised from the water bottom B until the lowest parts of the spuds 20A and 20B are close to the water surface S, and stored on the deck 3 of the work pontoon 1A. In this state, move from the installation area and return to the sea. This navigation uses the propulsion system if the work pontoon ship 1A is equipped with the propulsion system, but the propulsion system is used for self-navigation, but when towed by a tugboat, etc. Sail and return to port.

Next, a work pontoon used in the method for constructing an offshore structure according to the second embodiment of the present invention will be described. As shown in FIGS. 31 to 33, the work pontoons 1C and 1D are the same as the work pontoons 1A and 1B used in the method of constructing an offshore structure according to the first embodiment, and include half SEP and full SEP. However, the arm-shaped structure (projection) 4a of the stern fork part 4 is configured so that the mobile mounting table 30A on which the upper structure 41 is mounted and mounted can be fixed. Is different.

In addition, in this work pontoons 1C and 1D, if the movable mounting table 30A is configured to be able to travel and be fixed not only to the fork part 4 of the stern but also to the deck 3, a plurality of superstructures 41 are transported at one time. It is more preferable because it is possible. In this case, not only the first passage for moving the “movable mounting table 30A on which the upper structure 41 is mounted” arranged on the deck 3 to the fork part 4 at the stern, but also the “upper structure 41 It is necessary to provide a second passage for returning the emptied mobile mounting table 30A "from the fork portion 4 at the stern to the deck 3.

Further, since the work pontoons 1C and 1D do not necessarily need to be equipped with the walking-type lifting / lowering leg raising / lowering system 21b, the description here will be given on the stern side fork portion as shown in FIGS. 31 to 33. A pair of left and right fixed type stern side spuds 20A are provided in the vicinity of each of No. 4 and a fixed type spud 20A is provided at the center of the bow side.

And, as shown in FIG. 34, the first mobile trolley 30A has a base trolley 31 including a wheel trolley 32 that travels on the rails 8 arranged on the work pontoons 1C and 1D. Consists of The base bogie 31 traveling on the rail 8 can be configured to have a structure similar to that of a mobile crane of a shipyard. Further, it is configured to have a recess A on the rear side through which the joined body 40 of the upper structure 41 and the lower structure 42 passes. Further, a driver's cab 33 is provided as needed.

The movable mounting table 30A is a self-propelled trolley equipped with an internal combustion engine or an electric motor, or pulls the trolley by winding a wire 9a such as a mooring winch 9 provided before and after the work platform 1C, 1D. It consists of a trolley that moves. 31 to 33, two winches 9 are provided on the deck 3 on the stern side, and two winches 9 are provided on the side surface of the protruding portion 4a so as not to hinder the traveling of the mobile mounting table 30A. , They are arranged respectively. With this configuration, it is not necessary to equip the work pontoons 1C and 1D with a new device for moving the mobile mounting table 30A, so that the work pontoons 1C and 1D can be prevented from increasing in size.

In addition, the movable mounting table 30A moves on the mounted upper structure 41 in a direction intersecting the traveling direction, for example, a left-right direction moving mechanism, for example, although not shown, on a base carriage of the movable mounting table 30A. Further, if a slide table that is provided with rails and moves on the rails is provided, it is possible to quickly and accurately position the movable mounting table 30A in the left-right direction without using the spudder moving operation in the position adjustment process. Can be matched.

Then, in the method for constructing an offshore structure according to the second embodiment of the present invention, in the position adjusting step, the upper structure 41 in a state of being mounted on the mobile mounting table 30A is moved to the mobile mounting 30A. By horizontally moving the work table boats 1C and 1D, the lower joint portion 41d of the upper structure 41 and the upper joint portion 42a of the lower structure 42 mounted on the movable mounting table 30A are connected. Align.

As for the horizontal movement, the upper structure 41 can be moved in the front-rear direction of the work pontoons 1C and 1D by moving the base carriage of the movable mounting table 30A on the rail 8. Further, by moving the slide base of the movable mounting base 30A in the left-right direction with respect to the base carriage 31 by an electric motor, a hydraulic cylinder, or the like, the upper structure 41 on the slide base is moved to the work platform 1C, 1D. Can be moved left and right. By using both of them together, the upper structure 41 can be moved in the horizontal direction of the work pontoons 1C and 1D.

In addition to the slide stand, a wheel carriage 32 on the rail 8 is provided with a guide mechanism for the base carriage 31, and the wheel carriage 32 is moved by pushing the wheel carriage 32 in the left and right direction by expanding and contracting a piston of a hydraulic cylinder. The upper structure 41 can be moved in the left and right directions of the work pontoons 1C and 1D also by being provided so as to be possible. Also, other configurations may be used.

With this, since the positioning can be performed by moving the movable mounting tables 30A and 30B in the horizontal direction, the positioning can be performed quickly and accurately regardless of the spud moving method of the walking type deck lifting system. In addition, it is possible to perform alignment without using a walking type deck lifting system. In addition, when a walking type deck lifting system is provided, it may be used together with the spud moving method.

Further, in the carrying process, the mobile mounting table 30A in which the upper structure 41 is mounted is mounted on the work pontoons 1C and 1D as it is, so that the upper structure 41 is mounted on the work pontoons 1C and 1D. .. Regarding this mounting, the work pontoons 1C and 1D are configured so that they can be docked on the quay C from the stern side, and further, the rail on the quay C side and the rail 8 of the work pontoons 1C and 1D can be connected. In this case, in the case where the fork portion 4 is equipped with a mounting portion tilting mechanism, as in the above-described work pontoons 1A and 1B, the tilt of the fork portion 4 is changed with respect to changes in the attitude of the hull. It is preferable to avoid the inclination of the upper structure 41 during the mounting work by changing or maintaining the angle so that the berth C can be easily docked.

As a result, the upper structure 41 can be mounted in advance on the mobile mounting table 30A, and the connection work between the rail on the quay C side and the rails 8 of the work pontoons 1C and 1D and the mobile mounting table can be performed in advance. The upper structure 41 can be quickly mounted on the work pontoons 1C and 1D only by moving the work 30A and fixing the movable mounting base 30A to the fork portion 4 or the like. In this case, the crane work and the crane work affected by the wind become unnecessary.

If there is a crane on the quay C side and the effect of wind is small, you may use a crane. In this case, the superstructure 41 is placed on the mobile mounting table 30A already mounted on the work pontoons 1C and 1D, or on the mobile mounting table 30A previously mounted on the work pontoons 1C and 1D by the crane. It is mounted by lifting it with a crane. Alternatively, the mobile mounting table 30A on which the upper structure 41 is mounted is lifted up and mounted on the work table ships 1C and 1D.

Next, a work pontoon used in the method for constructing an offshore structure according to the third embodiment of the present invention will be described. As shown in FIGS. 35 to 37, the work pontoons 1E and 1F are the same as the work pontoons 1C and 1D used in the method for constructing an offshore structure according to the second embodiment, and include half SEP and full SEP. However, the arm-shaped structure (projection) 4a of the stern fork part 4A is configured so that the mobile mounting table 30B on which the upper structure 41 is mounted and mounted can travel. Is different.

In addition, as shown in FIGS. 35 to 37, in the work pontoons 1E and 1F, the second movable mounting table 30B is moved not only on the fork portion 4A of the stern but also on the deck 3 to set a predetermined arrangement. It is configured to be fixed in place. This makes it possible to carry a plurality of upper structures 41 at the same time and to perform installation work, which is more preferable. In this case, the "movable mounting table 30B on which the upper structure 41 is mounted" and the "movable mounting table 30B that is empty after the upper structure 41 is installed" arranged on the deck 3 are the decks. It is necessary to keep on passing on 3.

The second mobile mounting table 30B differs from the first mobile mounting table 30A shown in FIG. 34 in that the wheel carriage 32 is a tire-equipped carriage. It consists of a dolly that can be moved. This trolley can be constructed in a shipyard at a structure similar to a self-propelled trolley for transporting building blocks of a ship, for transporting tire blocks of a hull, and a large-scale self-propelled carrier for transporting heavy goods. When the vehicle can travel on the flat ground as described above, the upper structure 41 can be mounted on the work pontoons 1E and 1F by only moving in a plane without using a crane or the like. In addition, in these self-propelled carts and large-scale self-propelled carriers, the loading weight is about 70t to 700t.

Then, in the method for constructing an offshore structure according to the third embodiment, in the position adjusting step, the upper structure 41 in a state of being mounted on the mobile mounting table 30B and the mobile mounting table 30B on the work platform ship. 1E and 1F are moved horizontally to align the lower joint 41d of the upper structure 41 and the upper joint 42a of the lower structure 42 mounted on the movable mounting table 30B. To do.

As for the horizontal movement, the upper structure 41 can be moved in the front-rear direction and the left-right direction of the work pontoons 1C and 1D by moving the movable mounting table 30B forward and backward or by moving the table width. In addition, when the movable mounting table 30B is provided with a mechanism capable of moving laterally, it is possible to easily perform horizontal movement and position adjustment by lateral movement instead of width adjustment.

Further, in the transportation process, by mounting the mobile mounting table 30B with the upper structure 41 mounted on the work pontoons 1E and 1F, the upper structure 41 is mounted on the work berths 1E and 1F. Regarding this mounting, the work pontoons 1E and 1F are configured so that they can be docked on the quay C from the stern side, and further, the ground on the quay C side can be connected to the forks 4A of the work pontoons 1E and 1F. In this case, the fork portion 4 provided with the mounting portion tilting mechanism is configured to be used also as a ramp way so that the berthing work can be performed quickly, and the movable mounting table 30B is provided with the protruding portion 4a from the quay wall C side. It is more preferable that the vehicle can be run on and moved.

Thereby, the upper structure 41 can be mounted in advance on the mobile mounting table 30B, and the berthing work of the work pontoons 1E and 1F on the quay C side and the moving work of the mobile mounting base 30B are simply performed. Then, the upper structure 41 can be quickly mounted on the work pontoons 1E and 1F only by fixing the movable mounting table 30B to the fork portion 4A or the deck 3 or the like. In this case, the crane work and the crane work affected by the wind become unnecessary. Moreover, since the degree of freedom in the traveling direction is greater than that of the first movable mounting table 30A traveling on the rails 8, the fixing work and the alignment work can be performed more quickly.

Next, a work pontoon used in the method for constructing an offshore structure according to the fourth embodiment of the present invention will be described. As shown in FIGS. 38 to 40, the work pontoons 1G and 1H are the same as the work pontoons 1C and 1D used in the method for constructing an offshore structure according to the second embodiment, and include half SEP and full SEP. However, the elevator structure includes an elevator floor 4b that moves up and down with respect to the arm-shaped structure (projection) 4a of the stern fork portion 4B.

As this elevator structure, it is possible to use the elevator structure for aircraft that the aircraft carrier has. It should be noted that the first or second movable mounting table 30A, 30B can be mounted on the lifting floor 4b, and the mounting method, the positioning method, etc. of the construction method of the second or third offshore structure. May be used. Also, the carrier side elevator for the aircraft carrier (port side elevator) has a loading capacity of 30 to 60 tons and a hoisting speed of 10 seconds to move from the deck to the deck below and its size is (10m to 26m) x ( It is about 10 m to 16 m). If the loaded weight of one elevator is insufficient, it can be dealt with by synchronizing and operating a plurality of elevators.

Furthermore, at least one or both of a front-back direction moving mechanism that moves the lifting floor 4b in the front-rear direction of the work pontoons 1G, 1H and a left-right direction moving mechanism that moves the lifting floor 4ab in the left-right direction of the work pontoons 1G, 1H are used. With this configuration, the upper structure 41 mounted on the lifting floor 4ab is used by using the front-rear direction moving mechanism and the left-right direction moving mechanism in the movement adjusting step, the position adjusting step, and the horizontal movement separating step. It is possible to easily perform the alignment with respect to the lower structure 42 and the vertical separation of the lifting floor 4b from the joined body 40.

Further, in the approaching method and the scooping method in the loading step of the transportation step, the spud 20A of the work pontoons 1G and 1H may be raised and floated on the water surface S. After the vessel 2 is fixed to the bottom and floated on the water surface S while receiving the buoyancy of the hull 2, or is lifted above the water surface S, the hull 2 is fixed, and then the elevating floor 4ab is moved up and down. 41 is mounted on this lifting floor 4b. As a result, the influence of disturbances such as waves, swells, tidal currents, and wind can be reduced, so that the berthing of the lifting floor 4b to the quay C and the berth C of the upper structure 41 to the work pontoons 1G, 1H can be performed more quickly. Can be moved.

Similarly, also in the vertical descending process of the descending process and the separating process, the spud 20A of the work platform 1G, 1H is bottomed to descend or rise the mounting portion, and the water surface S is received while receiving the buoyancy of the hull 2. It is performed by elevating the elevating floor 4b while floating on the floor or in a state of being lifted above the water surface S. That is, the lifting floor 4b is lifted instead of the spud lifting operation.

According to the above-mentioned construction method for an offshore structure, the upper structure 41 assembled and integrated on land and transported by the work pontoons 1A and 1B can be used without using a hanging facility such as a large crane. Also, the work platform 1A, 1B can be moved up and down faster than the draft adjustment of the work pontoons 1A, 1B, and the upper structure 42 can be safely and quickly joined to the lower structure 41 arranged in the installation water area in a short time.

1A, 1C, 1E, 1G Workbench (Half SEP)
1B, 1D, 1F, 1H Workbench (Full SEP)
2 hulls 3 decks (deck)
4 Fork 4a Arm-like structure (projection)
4b Lifting floor 5 Upper structure 6a Mooring line 6b Anchoring line 7a Azimuth thruster 7b Side thruster 8 Rail 9 Winch 9a Wire 20A Spud (fixed type)
20B spud (kick type)
21A Lifting leg lifting system (fixed type)
21B Lifting leg lifting system (kick type)
22a Fixed bottom plate 22b Openable bottom plate 22c Tower tip 30A Mobile mounting table (rail type)
30B Mobile stand (tire type)
40 Offshore structure 41 Upper structure 41a Tower 41b Nacelle 41c Blade 41d Lower part of upper structure 42 Lower structure 42a Upper part of lower structure A Recess B Water bottom (seabed)
C Quay Cb Quay pedestal D, D1, D2, D3, D4 Vertical distance (vertical spacing)
S water surface

Claims (5)

1. A manufacturing process of dividing an offshore structure into an upper structure and a lower structure,
   An installation step of transporting and installing the lower structure in an installation water area,
   A carrying step of carrying the superstructure on a work table ship and carrying it to the installation water area,
   A step of moving the upper structure mounted on the work pontoon to an upper portion of the lower structure installed in advance by moving the work pontoon;
   By lowering the bottom of the spud of the deck lifting system provided in the work platform, the work platform is floated on the water surface while receiving the buoyancy of the hull, or above the water surface. In the lifted state, the bottoming process to support the installation water area,
   The upper structure mounted on the work pontoon by lowering a part or all of the work pontoon by a spud lifting operation for lifting and lowering the spud of the deck lifting system provided on the work pontoon. A descending step of descending the above onto the lower structure,
   A joining step of joining and integrating the upper structure with the lower structure to form a joined body of the upper structure and the lower structure;
   A separation step of separating the work platform from the joined structure of the upper structure and the lower structure,
   A method for constructing an offshore structure, which includes:
2. While including a position adjustment step after the bottoming step, in the position adjustment step, by moving the position of the work platform in the horizontal direction by a spud movement operation using a spud of the walking type deck lifting system, The method for constructing an offshore structure according to claim 1, wherein the lower joint portion of the upper structure and the upper joint portion of the lower structure mounted on the work platform are aligned with each other. ..
3. The detaching step raises or lowers the portion of the work platform on which the superstructure was mounted by a spud raising / lowering operation using the spud of the deck raising / lowering system, whereby the work platform is joined to the joined body. The method for constructing an offshore structure according to claim 1 or 2, further comprising a vertical separation step of separating the vertical structure from the vertical direction.
4. In the detaching step, the work pontoon is horizontally moved away from the joined body by moving the work pontoon in a horizontal direction by a spud movement operation using a spud of the walk-type deck lifting system. The method for constructing an offshore structure according to any one of claims 1 to 3, further comprising a horizontal separation step.
5. In a work pontoon equipped with a mounting part for mounting an upper structure of an offshore structure to be transported to and installed in an installation water area and a spud of a deck lifting system for lifting and lowering the hull, the mounting part is the hull of the work berth. A work pontoon, which is equipped with a mounting portion tilting mechanism that tilts with respect to the above.

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