JP5510692B1 - Steel temporary deadline installation method and low-air mobile crane carrier used therefor - Google Patents

Abstract

A temporary deadline is installed in a low-altitude environment while reducing the construction period and cost.
A low-crane mobile crane carrier 10 includes a carrier portion 12 and a crane 14. The carrier portion 12 has a U-shape with a recess 20 on one side of a rectangle in plan view. It is. The crane 14 has a height H corresponding to a low head environment, and further includes a suspension 30 that can move in parallel in the vertical and horizontal directions on the carriage 12. Using such two low-flying mobile crane carriages 10, the structure to be constructed is sandwiched between the recesses 20 so as to efficiently form and install the steel temporary cutoff. In addition, the low-air mobile crane carrier 10 can lift a large member composed of a plurality of steel members and the like in a low-head environment compared to a conventional crane carrier. For this reason, the cost can be reduced and the construction period can be shortened.
[Selection] Figure 1

Description

  The present invention relates to a steel temporary deadline installation method and a low-air mobile crane carrier used in this method.

  2. Description of the Related Art Conventionally, when repairing or seismic retrofitting a structure such as a pier submerged in a river, a construction method has been used in which a temporary deadline is installed to form a dry-up space around the structure. As one of such methods, there is a method of placing steel sheet piles around the structure, but since this method involves many steel sheet pile joints, in construction of river areas subject to restrictions on the construction period, There was a problem of taking too much time. In order to alleviate such problems, as another construction method, for example, a method for floating the to-be-prepared temporary closing box to the periphery of the structure and then sinking it around the structure (see Patent Document 1), or a plurality of steels There has been proposed a construction method (see Patent Document 2) or the like in which a divided temporary deadline constituted by a panel made of steel is set after being joined around a structure.

JP 2005-213803 A JP 2002-235328 A

However, although the construction method using the temporary closing box can shorten the construction period, the manufacturing cost of the temporary closing box increases, which is disadvantageous in cost. On the other hand, the construction method using steel panels is advantageous in terms of cost compared to the construction method using a temporary deadline box, but it requires a joining operation according to the quantity of the divisional temporary deadlines. End up. Furthermore, when a bridge pier with a low head under the bridge girder is to be constructed, a general crane cannot be used, so it is necessary to attach a special hanging jig to the bridge pier or bridge girder to set the temporary deadline. there were.
This invention is made | formed in view of the said subject, The place made into the objective is to install a temporary deadline in a low sky environment, reducing a construction period and cost.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

  (1) In order to form a cylindrical dry-up space around a structure that is at least partially submerged in a low-altitude environment, two structures of the above-mentioned mobile crane carrier for low altitude are used. Is a steel temporary deadline installation method in which a steel temporary deadline is installed so as to surround the periphery of the mobile crane, and the low-air mobile crane carrier has a U-shape extending in a vertical direction and a horizontal direction in a plan view. A suspending portion that is installed on the base boat portion and includes a crane having a height corresponding to a low head, and the crane is movable in parallel in the vertical direction and the horizontal direction on the base boat portion. A steel provisional deadline installation method (Claim 1).

  The steel temporary deadline installation method described in this section is to install a steel temporary deadline around a structure using two low-air mobile crane carriers in a low-head environment. The low-air mobile crane carrier used in this construction method includes a carrier part and a crane. The carrier part has a U-shape extending in the vertical direction and the horizontal direction in a plan view, that is, a rectangular shape extending in the vertical direction and the horizontal direction in a plan view, with a recess provided near the center of one side. is there. In addition, the crane installed on the trolley has a height corresponding to the low head environment, such as under the bridge girder where the pier is submerged, and further, the vertical and horizontal directions on the trolley. And a suspension part that can be translated in parallel. Examples of such cranes include overhead cranes and bridge cranes.

  For this reason, the crane of the low-flying mobile crane carrier of this construction method needs to work with the boom tilted under a low head, such as a crawler crane, so the suspension load will be greatly reduced. Unlike cranes mounted on trolleys, they are not subject to suspension loads due to their low head. Further, since the U-shaped concave portion is included and can be translated in the vertical and horizontal directions on the base boat portion, a large load is suspended in a state where a part of the load is submerged in the concave portion. Therefore, the steel temporary deadline installation method described in this section uses the low-air mobile crane carrier as described above, which is more than the case of using a conventional crane carrier, despite the low head environment. Will be able to handle large loads stably, which will contribute to shortening the construction period. Further, since the load is lifted by the crane of the low-air mobile crane carrier, there is no need to install temporary materials such as a lifting jig on the construction target object. Furthermore, work can proceed efficiently by using the low-air mobile crane carrier as a water scaffold when forming or installing a steel temporary deadline.

  (2) In the above item (1), a split provisional deadline having a shape obtained by dividing the cylindrical shape into two in the radial direction is attached to each of the two low-flying mobile crane carriages by the crane. A loading step of loading in a state of being lifted in a concave portion, a mooring step of mooring the two low-flying mobile crane carriages at a position where the structure is sandwiched between the concave portions, and the split temporary While adjusting the position of the deadline, the divided temporary deadlines are joined to surround the structure to form a tubular steel temporary deadline, and the steel is adjusted while adjusting the position by the crane. A steel temporary deadline installation method including a sinking step of sinking a temporary cutoff made around the structure (claim 2).

The steel temporary deadline installation method described in this section is the loading process for loading the steel temporary deadline into the low-air mobile crane carrier, and the low-air mobile crane carrier is moored in place. It includes a mooring step, a forming step for forming a steel temporary deadline, and a setting step for setting a steel temporary deadline.
In the loading step, as a member for forming the steel temporary deadline, a divided temporary deadline having a shape obtained by dividing the cylindrical body into two in the radial direction is loaded into each of the two low-air mobile crane carriers. At this time, it is assumed that the divisional provisional deadline is lifted and loaded in the concave portion of the U-shaped carriage by the crane of the mobile crane carrier for low altitude. As a result, even if the size of the divisional provisional deadline is larger than the height of the crane corresponding to the low head, the divisional provisional deadline can be obtained while the part is submerged by lifting it in the recessed portion where the water surface is exposed. Is to lift. Note that each of the above-described divided provisional deadlines may be constituted by a plurality of smaller steel members or the like as necessary.

Also, in the mooring process, two low-air mobile crane stands at a position where the construction object is sandwiched between the U-shaped concave portions of the two low-air mobile crane carriers. Moor the ship. That is, the protrusions located on both sides of the recessed portion of the base boat portion are moored at a position where the structure is sandwiched between the concave portions in such a manner that the low-air mobile crane base boats face each other. At this time, for example, two low-climbing mobile crane carriers are moored while adjusting the position by using winches and spuds provided in the low-crane mobile crane carrier.
Then, in the forming step, the two divided temporary deadlines that are lifted by the two moored mobile crane carriers for low altitude are combined while adjusting the position while being lifted by the crane. Each of the divided temporary deadlines is a shape obtained by dividing the cylindrical body into two in the radial direction, so that the cylindrical steel temporary deadlines that surround the structure are joined by sandwiching the structure with the divided surfaces facing each other. Form.

Also, in the settling process, the formed cylindrical steel temporary deadline is submerged into the water while adjusting the position and angle with respect to the structure by the cranes of the two low-air travel mobile crane carriers. Sink around the structure.
Therefore, when the steel temporary cutoff installation method described in this section is used to form a cylindrical steel temporary cutoff from a divided temporary cutoff formed by dividing the cylindrical body into two in the radial direction, This requires less work to join the divisional provisional deadline and contributes to shortening the construction period. Furthermore, even if the divided temporary deadline is composed of a plurality of smaller steel members, etc., if they are configured in the above-mentioned divided temporary deadline state in advance, the installation cost of the steel temporary deadline is set. Is suppressed, and the cost is reduced.

  (3) In the step (2), when there is no steel temporary deadline already set, the steel temporary deadline is set on the foundation of the structure, and the steel is already set. When there is a provisional deadline, after the steel provisional deadline is deposited so as to be stacked on the already-prepared steel provisional deadline, the subsidized steel provisional deadlines are joined together, and the loading step, A steel temporary deadline installation method in which the mooring step, the forming step, and the laying step are repeated until the upper end of the uppermost steel temporary deadline that has been laid down reaches a height above the water (Claim 3).

The steel provisional deadline installation method described in this section is a subsidence around the structure where the steel provisional deadline is first installed for the construction target structure in the subsidence process of substituting the steel provisional deadline. When there is no finished steel temporary deadline, the steel temporary deadline is set on the foundation of the structure. On the foundation of the structure, a receiving surface of a steel temporary cutoff may be formed in advance with underwater concrete or the like.
On the other hand, in the sinking process, if there is a steel temporary deadline that has been set around the structure, such as the installation of a second or subsequent steel temporary deadline for the structure, A new steel temporary deadline to be installed this time is set on the deadline so as to be stacked in the cylindrical axial direction. Thereafter, the steel temporary deadline that has already been set up and the steel temporary deadline that has been set up this time are joined together with the cylindrical end surfaces thereof to form a cylindrical steel temporary deadline that is longer in the depth direction.

Then, by repeating the loading process, the mooring process, the forming process, and the laying process described above until the upper end of the laid uppermost steel temporary deadline reaches a height above the water, the structure around the structure A cylindrical steel temporary deadline having a length reaching from the foundation to the water is formed.
For this reason, the steel provisional deadline installation method described in this section uses a low-air mobile crane carrier even when installing a steel provisional deadline for a structure that has been submerged to a deep foundation. A cylindrical steel temporary deadline that can be handled is stacked in the axial direction to extend from the foundation of the structure to the water, and has a length sufficient to form a dry-up space inside. The steel temporary deadline is efficiently installed in a low head environment.

(4) In the mooring step of (2) or (3) above, the temporary steel made by rigidly connecting the tips of the U-shaped protrusions of the two low-air travel mobile crane carriers Deadline installation method (Claim 4).
In the mooring process, the steel temporary deadline installation method described in this section is used when two low-air mobile crane carriers are moored at a position where a structure is sandwiched between U-shaped recesses. The leading ends of the protrusions to be abutted between the base boats are rigidly connected.
Here, in a crane carrier, normally, when a load is lifted by a crane, the horizontal state of the carrier is maintained by maintaining a weight balance with the suspended load by ballast water or the like poured into the ballast tank. For this reason, immediately after the load of the suspended load disappears, such as when the load is released from the crane, the base boat tilts due to the influence of the weight of the ballast water etc. that kept the weight balance with the suspended load. In order to return the trolley to a horizontal state, it is necessary to move the ballast water with a pump.

  Therefore, the steel temporary deadline installation method described in this section uses a crane of two low-air travel mobile crane carriages at a substantially line-symmetrical position centered on the structure in a plan view. The steel temporary deadline is laid down from the state where the temporary deadline is lifted in a balanced manner. After the steel temporary deadline lifted by the crane settled down and the load of the suspended load disappeared, the weight of the ballast water that kept the balance of each low-air mobile crane carrier was The two low-flying mobile crane carriages that are rigidly connected to each other are shared like a single carriage. As a result, the weight of the ballast water of the two low-air mobile crane carriers is balanced in a direction orthogonal to the line passing through the rigid position in plan view. Inclination in the orthogonal direction does not occur. On the other hand, the inclination of the line segment direction passing through the rigid connection position in a plan view of the mobile crane carrier for low altitude depends on the position of the line segment direction where the steel temporary deadline was lifted, but the line concerned was concerned. It is smaller than the inclination in the direction perpendicular to the minute and only slightly inclined. Therefore, the crane can be prevented from coming into contact with the bridge girder even immediately after the steel temporary closing load lifted by the mobile crane carrier for low altitude disappears.

(5) In the above paragraphs (1) to (4), two cranes are provided on the crane of the low-air mobile crane carrier, and the two cranes are provided as necessary in each step. A steel temporary deadline installation method that operates synchronously (Claim 5).
In the steel temporary deadline installation method described in this section, two hanging parts are provided on the crane of the low-air mobile crane carrier, and in each step described above, for example, the position of the divided temporary deadline lifted by the crane is adjusted. The two suspension portions are operated synchronously as necessary, for example, when performing, so that the position adjustment of the divisional temporary cut-off can be performed efficiently while maintaining a balance.

(6) The steel temporary closing installation method in which the four suspension parts in total in the two crane carrier ships are operated synchronously as necessary in the forming step and the staking step in the above item (5) (Claim 6).
The steel provisional deadline installation method described in this section is used to adjust the position of the cylindrical steel provisional deadline that is lifted by, for example, two low-air mobile crane carriers in the formation process and the setting process. When necessary, the position of the steel temporary cutoff is adjusted efficiently while maintaining balance by synchronously operating the four suspension parts in total for the two crane carrier ships as necessary. .

(7) In the above items (1) to (6), the base ship portion of the low-air mobile crane carrier is configured by a plurality of assembly carrier, and the size of the structure and the surrounding environment of the structure In addition to this, a steel provisional deadline installation method for changing the size of the trolley part by changing the combination of the assembly trolleys (Claim 7).
The steel provisional deadline installation method described in this section consists of a low-air mobile crane carrier with multiple assembly carriers, which are assembled according to the size of the structure to be constructed and the surrounding environment. The size of the trolley part is changed by changing the combination of the trolleys. For example, when there is another structure around the structure to be constructed, two low-air units are installed at a position where the structure to be constructed is sandwiched without interference from another structure. The pedestal part of the low-air mobile crane carrier is constructed to have a size that can moor the mobile crane carrier. In this way, the work is efficiently performed flexibly corresponding to the size of the structure and the surrounding environment. Furthermore, by transporting the low-level mobile crane carrier to the construction site in a state where it is divided into multiple assembly carriers, it is easy to carry regardless of whether it is on water or on land. It is to be transported.

(8) In the above items (1) to (7), a steel temporary closing installation method including a floor digging process for removing earth and sand around the structure until at least a part of the foundation of the structure is exposed in water. (Claim 8).
The steel provisional deadline installation method described in this section is a floor digging that removes the soil around the structure until at least part of the foundation of the structure to be constructed, for example, the upper end surface of the foundation is exposed in water. It includes a process. This floor excavation process is performed prior to the other processes described above. For example, the sand pump is submerged from the work ship in the underwater sand around the structure, and the sand pump sucks up the earth and sand into the earth transport ship. The soil around the structure is removed. Alternatively, earth and sand around the structure may be removed by a BH method using a boring machine. Even if it is a case where a steel temporary deadline is installed for a structure in which the foundation is buried in underwater earth and sand, the subsequent process after removing the earth and sand around the structure in the floor excavation process By doing this, the steel temporary deadline will be laid down more reliably on the foundation of the structure.

(9) A U-shaped mobile crane carrier used for construction on the water or underwater, including lifting work in a low-altitude environment, and extending in the vertical and horizontal directions in plan view And a crane having a height corresponding to a low head, the crane is capable of translating vertically and laterally on the base boat portion. A low-rise mobile crane carrier that is an overhead crane that includes two traveling rails that are provided in parallel and that extend in parallel to each of the U-shaped protrusions .

The low-climbing mobile crane carrier described in this section is a low-headed head, for example, when the steel temporary deadline installation method described in (1) above is used, or when a scouring block is set around a submerged pier. It is a low-air mobile crane carrier used for construction on the water or underwater, including the lifting work of the load in the environment. This low altitude mobile crane carrier includes a carrier and a crane, and the carrier is a U-shape extending in the vertical direction and the horizontal direction in plan view, that is, in the vertical direction in plan view. And it is the shape where the recessed part was provided near the center of one side of the rectangle extended in the horizontal direction. Moreover, the crane is installed on the trolley part, and has a height corresponding to a low sky head environment such as under a bridge girder where a pier is submerged. Furthermore, the crane is provided with a suspension portion that can move in parallel in the vertical direction and the horizontal direction on the carriage. The crane mounted on the low-flying mobile crane carrier having these characteristics is installed in parallel and has two traveling rails extending to each of the U-shaped protrusions. It is an overhead crane provided.

  For this reason, the crane of this mobile crane carrier for low altitude, such as a crawler crane, needs to work in a state where the boom is tilted under a low head, so that the suspension load is greatly reduced. Unlike cranes outfitted on trolleys, they are not subject to suspension loads due to their low head. Furthermore, since it includes a U-shaped concave portion and can be translated in the vertical and horizontal directions on the carriage, a large load is suspended with a portion of the load submerged in the concave portion. Therefore, the mobile crane carrier for low altitude described in this section can handle a large load stably compared with the conventional crane carrier in a low head environment. This will contribute to shortening. Furthermore, the low-air mobile crane carrier can be used as a water scaffold during construction, so that work on the water and in water can proceed efficiently.

(10) In the above (9), a low-air mobile crane carrier used in one set in a form in which the construction target position is sandwiched between the U-shaped concave portions (claim 10).
The mobile crane carrier for low altitude described in this section is used as a set of two units in a manner in which the construction target position such as a submerged bridge pier is sandwiched by the concave portion of the U-shaped carrier unit described above. Is. Two low-air mobile crane trolleys, even if the protrusions located on both sides of the concave portion of the trolley part are close to the position where the low-air mobile crane trolleys contact each other, depending on the construction contents Or it may be moored at a slightly spaced position. By using the cranes of the two low-flying mobile crane carriages arranged in this way individually or in combination, it is possible to easily install and pull up the members surrounding the construction object. Furthermore, by using the two low-flying mobile crane carriages arranged so as to surround the construction target position as the water scaffold for construction, the work on the water and underwater can be performed efficiently.

(11) A low-air mobile crane carrier in which the tips of the U-shaped protrusions are rigidly connected between two in (10).
The mobile crane carrier for low altitude described in this section is used as a set of two, and the tips of the U-shaped protrusions are 2 in a state where the construction target position is sandwiched between the U-shaped concave portions. It is rigidly connected between the stands.
Generally, when a crane carrier lifts a load with a crane, the weight balance with the suspended load is maintained by the ballast water injected into the ballast tank, so that the horizontal state of the carrier is maintained. Yes. Therefore, immediately after the suspended load is released, such as when the suspended load is released from the crane, the trolley is tilted by the weight of the ballast water or the like that maintains the weight balance with the suspended load. Furthermore, in order to return the carriage to the horizontal state, it is necessary to move the ballast water with a pump.

Therefore, the low-air mobile crane carrier described in this section is used as a set of two units, and the ends of the U-shaped projections are rigidly connected to each other. For example, two cranes If you lift one suspended load or separate suspended loads that are close in weight to release the suspended load at the same time with two cranes, the ballast water that kept the balance of each mobile crane carrier for low altitude Will be shared by two trolleys. As a result, the weight of the ballast water of the two mobile crane carriages for low altitude balances in the direction perpendicular to the line segment passing through the rigid connection position in plan view. No tilt occurs .

On the other hand, the inclination of the line segment direction passing through the rigidized position in a plan view of the mobile crane carrier for low altitude depends on the position of the line segment direction in which the suspended load is lifted, but the line segment concerned is concerned. The inclination is smaller than the inclination in the direction orthogonal to the direction, and the inclination is slight. Therefore, the crane is prevented from coming into contact with the bridge girder even immediately after the load of the suspended load lifted by the crane is lost.

( 12 ) In the above paragraphs (9) to ( 11 ), the crane is provided with a low-lift mobile crane carrier provided with two hoist-type suspension parts (claim 12 ).
In the low-air mobile crane carrier described in this section, the crane includes two hoist-type suspension parts. The hoist-type suspension unit achieves the same suspension capacity while being small compared to a normal winch. Therefore, by providing two such hoist type suspension parts, a lifting load necessary for construction is realized while saving space corresponding to a low head environment.

( 13 ) In the above item ( 12 ), a low-air mobile crane carrier that allows the two suspension parts to be operated synchronously (claim 13).
The mobile crane carrier for low altitude described in this section is efficient, while maintaining the balance, for example, by adjusting the position of the load lifted by the two suspension parts, because the two suspension parts of the crane can be operated synchronously. Often done.

( 14 ) In the above items (9) to ( 13 ), the base boat part is constituted by a plurality of assembly base ships, and the shape of the base ship part can be changed according to the combination of the plurality of base assembly parts. A low-air mobile crane carrier (claim 14 ).
In the low-air mobile crane carrier described in this section, the carrier is composed of a plurality of assembly carriers, and the shape of the carrier can be changed according to the combination of these assembly carriers. Is. For example, if there is another structure around the construction object, mooring the low-air mobile crane carrier to a position where the work can be performed without interference from another structure. The trolley is configured in a shape that allows Thus, work is efficiently performed by flexibly corresponding to the size of the construction target and the surrounding environment. Furthermore, if the trolley part of this low-flying mobile crane carrier is divided into multiple assembly carriers, it will be transported to the vicinity of the construction site, regardless of whether it is carried over water or on land. It will be easily transported.

( 15 ) In the above paragraphs (9) to ( 14 ), a low-air mobile crane carrier comprising a unic for material loading on the carrier part (claim 15 ).
The mobile crane carrier for low altitude described in this section is equipped with a unic for material loading on the base boat part, so that when the mobile crane base ship for low sky is constructed as a floating scaffolding, It is intended to efficiently load the necessary materials on the top and shorten the construction period.

  Since this invention was comprised in this way, it becomes possible to install a temporary deadline in a low sky environment, reducing a construction period and cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is a three-plane figure which shows the low-air mobile crane carrier which concerns on embodiment of this invention, (a) is a top view, (b) is a front view, (c) is a side view. It is a flowchart which shows the procedure of the steel temporary deadline installation construction method concerning embodiment of this invention. It is an image figure which shows the pier periphery for demonstrating a floor excavation process, (a) is the state which removed the earth and sand, (b) has shown the state which removed the earth and sand. It is an image figure for explaining a loading process, (a) shows the state which loads a division temporary deadline from a supply ship to a low-air mobile crane carrier, and (b) lifts a divisional temporary deadline. It is a perspective view which shows the mobile crane carrier for low altitudes in the state where it was. It is a plane image figure for demonstrating a mooring process, and has shown the state which carried out the temporary mooring of the two mobile crane carriers for low air. It is a plane image figure for demonstrating a mooring process, and has shown the state which moves one mobile crane carrier for low air to the other mobile crane carrier for low air. It is a plane image figure for demonstrating a mooring process, and has shown the state which moves the other mobile crane carrier for low air to the one side low mobile crane carrier. It is a plane image figure for demonstrating a mooring process, and has shown the state moored in the position which pinches | interposes two low-air travel mobile crane carriers. It is a plane image figure which shows the bridge pier periphery for demonstrating a formation process. It is a side image figure for demonstrating a setting process, and has shown the state which lifted up the 1st steel temporary deadline. It is a side image figure for demonstrating a setting process, and has shown the state which set the 1st steel provisional deadline. It is a side image figure for demonstrating a setting process, and has shown the state which lifted the 2nd steel temporary cutoff. It is a side image figure for demonstrating a setting process, and has shown the state which set the 2nd steel temporary cutoff. It is a side image figure for demonstrating a setting process, and has shown the state which lifted the 3rd steel temporary cutoff. It is a side image figure for demonstrating a setting process, and has shown the state which set the 3rd steel temporary deadline. It is the image figure which formed the dry-up space around the bridge pier after the steel temporary closing installation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 1 is a three-side view schematically showing a low-air mobile crane carrier 10 according to an embodiment of the present invention. The low-air mobile crane carrier 10 is used for construction in a low-airhead environment such as under a bridge girder on water, and is mounted on the carrier 12 and the carrier 12 as shown. The crane 14 is provided.

  As can be confirmed in FIG. 1A, the trolley portion 12 is formed in a U shape in which a concave portion 20 is provided on one side of the rectangle (the lower side in the drawing) in a plan view. On both the left and right sides of 20, the protrusions 22 protrude downward. Moreover, the base boat part 12 is comprised by several assembly base boats, and the shape and magnitude | size of the base boat part 12 can be changed by changing the quantity of assembly base boats, and arrangement | positioning of an assembly base boat. It has become.

  In the example of FIG. 1, the crane 14 is an overhead crane, and a crane girder 34 that travels in the vertical direction of FIG. 1A on two traveling rails 36 provided in the carriage 12, and this crane The structure includes two hoist type suspension parts 30 that traverse the girder 34 on the trolley 32 in the left-right direction in FIG. The two suspension parts 30 can be operated so that traversal on the crane girder 34, wire rope hoisting operation, and the like are performed individually, but can also be operated synchronously. The two traveling rails 36 extend to the vicinity of the tip of the protrusion 22 (the lower end of FIG. 1A), and the traveling of the crane girder 34 is within the laying range of the traveling rail 36 at each end. A travel stopper 38 for limiting is provided. Moreover, the crane girder 34 is provided with the escape prevention anchor 40 which prevents the escape at the time of a stop. Since the crane 14 has such a configuration, the range on the trolley including the concave portion 20 in which the two hanging portions 30 are defined by the two traveling rails 36 and the crane girder 34 is illustrated in FIG. Translate in the vertical and horizontal directions. The crane 14 has a height corresponding to a low head environment such as under a bridge girder on the water, and the height H from the water level during construction to the top of the crane 14 is, for example, less than 3 m. It is configured to be within an appropriate range for operation.

  1 includes a winch 50 and a wire 52 used for mooring the low-air mobile crane carrier 10, a ballast pump 54 for injecting and draining ballast water, and a crane 14. An operator room 56 for performing operations and the like is provided. Although not shown in FIG. 1, the low-flying mobile crane carrier 10 according to the embodiment of the present invention further loads materials on the spud, the carrier portion 12 used for mooring. The unic 58 (see FIG. 16), a sensor for preventing a collision between the crane 14 and the structure may be provided.

  Next, the steel temporary cutoff installation method according to the embodiment of the present invention will be described. This construction method uses a low-air mobile crane carrier 10 as illustrated in FIG. 1 to install a steel temporary deadline for forming a dry-up space around a submerged structure in a low-head environment. To do. Here, as an example, a case will be described in which three stages of tubular steel temporary cutoffs are installed around a submerged pier supporting the bridge girder in an environment where the height from the water surface to the bridge girder is 3 m or less. FIG. 2 is a flowchart showing an example of the temporary steel installation method for each process, which will be described with reference to FIGS. 3 to 15 along this flowchart. Refer to FIG. 1 for details of the low-air mobile crane carrier 10.

  S10 (floor digging step): A step of removing earth and sand around the structure until the foundation of the pier is exposed. Specifically, as shown in FIG. 3A, the earth and sand around the pier 72 that supports the bridge girder 70 is sucked up onto the earth ship 78 by the sand pump 74 submerged from the work ship 76. Then, the sand is sucked up while adjusting the position of the sand pump 74, and the sand around the pier 72 is removed until the upper portion of the foundation 72a of the pier 72 is exposed as shown in FIG. In addition, the trolley shown by the code | symbol 80 of Fig.3 (a) is a support trolley loaded with the generator etc. which are required for a floor moat process, and the code | symbol 72b of FIG.3 (b) is after removing earth and sand. The receiving surface of the steel temporary deadline formed on the foundation 72a with the underwater concrete is shown.

  S20 (loading step): This is a step of loading a divided temporary deadline for forming a steel temporary deadline into the low-air mobile crane carrier 10. For example, as shown in FIG. 4 (a), the divided temporary deadline 60 is lifted by a crane 82a from a supply ship 82 that supplies the divided temporary deadline 60, and each of the two low-flying mobile crane carriers 10A and 10B is used. Then, the divisional deadline 60 is loaded. The split provisional deadline 60 has a shape obtained by dividing the cylindrical body into two in the radial direction, and the length of the tubular axial direction (the height of the divided provisional deadline 60) is the crane 14 of the low-air mobile crane carrier 10. It is long compared to the height of. For this reason, as shown in FIG. 4 (b), in the low-air mobile crane carrier 10 (10A, 10B), the cylindrical body of the divisional provisional deadline 60 is divided into two in the radial direction in consideration of the formation process described later. In a state where the divided surface 60a is directed toward the opening side (lower right side in the figure) of the concave portion 20, and in a state where a part of the divided temporary deadline 60 is submerged in the concave portion 20 of the carriage unit 12, the crane 14 The divisional provisional deadline 60 is lifted up. The operation of the crane 14 is performed by radio from an operator room 56 provided on the carriage unit 12 in accordance with an instruction from an instructor who confirms the suspended state of the divisional provisional deadline 60, for example. Moreover, the weight balance with the division | segmentation temporary cutoff 60 is maintained with ballast water etc., and the horizontal state of the mobile crane carrier 10 for low air shall be maintained. In addition, in FIG.4 (b), illustration of the hanging part 30 of the crane 14, the wire rope etc. which suspend the division | segmentation temporary deadline 60 is abbreviate | omitted for convenience.

  S30 (Mooring Step): A step of mooring the two low-air mobile crane carriers 10A and 10B around the pier 72. Specifically, first, as shown in FIG. 5, the divisional provisional deadline 60 suspended in the recessed portion 20 is constructed by using the winch 50 and the wire 52 provided in each of the low-air mobile crane carriers 10A and 10B. Two low-climbing mobile crane carrier ships 10A and 10B are temporarily moored at positions facing each other across the target pier 72A. At this time, as in the example of FIG. 5, when another pier 72B is present in the vicinity of the pier 72A to be constructed, the divided temporary cutoff 60 is lifted by the crane 14 toward the upper side of the concave portion 20 in the drawing, and used for low altitude. The mobile crane carrier 10A, 10B is temporarily moored at a position closer to the lower side in the figure than the position of the target pier 72A so as not to interfere with another pier 72B. In addition, the base boat part 12 of the mobile crane carrier 10A, 10B for low altitudes is assumed to be configured in advance so as not to interfere with another pier 72B by a plurality of assembly base boats.

  Next, as shown in FIG. 6, the low-air mobile crane carrier 10B on the right side in the figure is moored by a spud (not shown), and the low-air mobile crane carrier 10A and the low-air mobile crane carrier 10B By operating the winch 50 over the wire 52 between them, the low-air mobile crane carrier 10A is moved to the low-air mobile crane carrier 10B (in the direction of the black arrow in the figure). Then, after moving the low-flying mobile crane carrier 10A to the position as shown in FIG. 7, the low-air mobile crane carrier 10A on the left side in the figure is moored by a spud (not shown), By operating the winch 50, the low-air mobile crane carrier 10B is moved to the low-air mobile crane carrier 10A (in the direction of the black arrow in the figure). And, as shown in FIG. 8, in a state where the split temporary deadlines 60 suspended in the recess 20 face each other across the bridge pier 72A, the projections 22 of the carriage 12 are abutted against each other. Two low-lift mobile crane carrier ships 10A and 10B are moored by spuds, wires 52, and the like. Thereafter, the tip ends of the protrusions 22 of the pontoon part 12 that are attached together are rigidly connected as indicated by reference numeral 24. The mooring method described above is an example, and mooring is performed using an appropriate mooring method according to the surrounding environment and circumstances.

S40 (formation step): This is a step of joining the divided temporary deadlines 60 lifted by the two low-air mobile crane carrier ships 10A and 10B to form a cylindrical steel temporary deadline. First, as shown in FIG. 8, in the two low-flying mobile crane carrier ships 10A and 10B, the crane 14 positions the divided temporary deadline 60 with the bridge pier 72A sandwiched between the split surfaces 60a. (Refer to FIG. 4 (b)). At this time, the two suspension portions 30 (see FIG. 1) of the crane 14 may be operated synchronously.
And as shown in FIG. 9, the division | segmentation surface 60a is match | combined, the division | segmentation temporary cutoff 60 is couple | bonded with a volt | bolt etc., and the cylindrical steel temporary cutoff 62 is formed so that the bridge pier 72A may be enclosed. At this time, the steel temporary cutoff 62 is in a state of being lifted by the cranes 14 of the two low-air mobile crane carriers 10A and 10B.

S50 (sinking step): This is a step of sinking the steel temporary cutoff 62 around the pier 72A. In the example of FIG. 2, it is determined whether the steel temporary cutoff has been set, the first sinking step, and the second sinking. It consists of a process and a coupling process. In this step, when adjusting the position of the steel temporary deadline 62, a total of four suspension parts 30 (see FIG. 1) of the two low-climbing mobile crane carriers 10A, 10B are synchronized. It is good also as operating.
S52 (determining whether or not a steel provisional deadline has already been set): It is determined whether or not there is a steel temporary deadline 62 that has already been set around the pier 72A. Then, when there is a steel provisional deadline 62 that has been laid down as shown in FIGS. 12 and 14 (YES), the process proceeds to S56, and when there is no steel provisional deadline 62 that has been laid down as shown in FIG. NO), the process proceeds to S54. 10 to 16, for convenience of illustration, a part of the steel temporary cutoff 62 (62A, 62B, 62C) is seen through.

  S54 (first laying step): As shown in FIG. 10, when the first steel temporary deadline 62A is installed without the steel temporary deadline 62 already set around the pier 72A, a low-air moving type The first steel temporary cutoff 62A is sunk toward the foundation 72a of the pier 72A while adjusting the position so as not to contact the pier 72A by the crane 14 of the crane carrier 10A, 10B. Then, as shown in FIG. 11, the first steel temporary cutoff 62A is set so that the lower surface of the steel temporary cutoff 62A is aligned with the receiving surface 72b formed on the foundation 72a. At this time, an anchor bolt may be driven into the underwater concrete forming the receiving surface 72b, and the first steel temporary cutoff 62A may be fixed by the anchor bolt. In addition, the code | symbol 55 of FIG. 11 has shown the ballast tank of the mobile crane carrier 10A, 10B for low skies.

  S56 (second laying step): As shown in FIGS. 12 and 14, when there is a steel temporary cutoff 62 that has been set around the pier 72A, the steel is stacked so as to be stacked on the steel temporary cutoff 62 that has been set. A provisional deadline 62 is set. More specifically, as shown in FIG. 12, the first steel temporary cutoff 62A has already been set on the receiving surface 72b of the pier 72A, and the second steel temporary cutoff 62B is further installed. In this case, the second steel provisional cutoff 62B is adjusted to the first steel provisional cutoff 62A while adjusting the position so as not to contact the pier 72A by the crane 14 of the mobile crane carrier 10A, 10B for low altitude. Sink towards Then, as shown in FIG. 13, the second steel temporary cutoff 62B is set so that the lower surface of the second steel temporary cutoff 62B is aligned with the upper surface of the first steel temporary cutoff 62A. To do.

  On the other hand, as shown in FIG. 14, a first steel temporary cutoff 62A and a second steel temporary cutoff 62B are already set around the pier 72A, and a third steel temporary cutoff is further provided. When installing the deadline 62C, the third steel temporary deadline 62C is adjusted to the second steel while the position of the crane 14 of the low-air mobile crane carrier 10A, 10B is adjusted so as not to contact the pier 72A. It sinks toward the steel temporary deadline 62B. Then, as shown in FIG. 15, the third steel temporary cutoff 62C is set so that the lower surface of the third steel temporary cutoff 62C is aligned with the upper surface of the second steel temporary cutoff 62B. To do.

  S58 (joining step): The steel provisional deadline 62 that has been deposited is joined to the steel provisional deadline 62 that has been deposited thereon. More specifically, as shown in FIG. 13, when the second steel temporary cutoff 62B is set on the first steel temporary cutoff 62A in S56, the first steel The temporary cutoff 62A and the second steel temporary cutoff 62B are coupled using a bolt or the like. As shown in FIG. 15, in S56, when the third steel temporary cutoff 62C is set on the second steel temporary cutoff 62B, the second steel temporary cutoff 62B The third steel temporary cutoff 62C is coupled using a bolt or the like.

  S60 (steel provisional cutoff height determination): It is determined whether or not the upper end of the subsidized steel temporary cutoff 62 is on the water. If the upper end of the steel temporary cutoff 62 is on the water (YES), this method is completed, and if the upper end of the steel temporary cutoff 62 is not on the water (NO), the process returns to S20. Then, the processes from S20 to S50 are performed again. Specifically, as shown in FIG. 15, when the upper end of the set-up steel temporary deadline 62, that is, the upper end of the third steel temporary deadline 62C in the example of FIG. Since the tubular steel temporary cutoff 62D having a sufficient height is installed in order to form a dry-up space around the pier 72A, the present construction method ends. On the other hand, as shown in FIGS. 11 and 13, when the upper end of the first steel temporary cutoff 62 </ b> A and the upper end of the second steel temporary cutoff 62 </ b> B are not on the water, a cylindrical shape Since the steel temporary deadline is insufficient, the process returns to S20 in order to stack a new steel temporary deadline and increase the height of the tubular steel temporary deadline.

  Then, after the installation of the temporary steel cutoff 62D so as to surround the pier 72A is completed, a dry-up space DS is formed inside the temporary steel cutoff 62D by a known method as shown in FIG. Perform 72A repair work. At this time, the low-air mobile crane carrier 10 is used as a floating scaffold for performing repair work and the like. Further, the UNIC 58 may be mounted on the low-air mobile crane carrier 10 and necessary materials such as repair work may be loaded from the material carrier 84.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained. In other words, the low-flying mobile crane carrier 10 according to the embodiment of the present invention has a load in a low-altitude environment, for example, when a steel temporary deadline or a scouring block is installed around a submerged pier. It is used for construction on the water or underwater including the lifting work. As shown in FIG. 1, the mobile crane carrier 10 for low altitude includes a carrier 12 and a crane 14. The carriage 12 has a U-shape extending in the vertical direction and the horizontal direction in plan view, that is, a rectangular shape extending in the vertical direction and the horizontal direction in plan view, and a recess 20 is provided near the center of one side. Shape. Further, the crane 14 installed on the carriage unit 12 has a height H corresponding to a low head environment such as under a bridge girder where the pier is submerged. The suspension part 30 is provided which can move in parallel in the horizontal direction. Crane 14 having such characteristics, while being placed parallel to and extend to each of the projections 22 of U-shaped, a overhead crane equipped with two running rails 36.

  For this reason, the crane 14 of the mobile crane carrier 10 for low altitude is required to work in a state where the boom is tilted under a low head, such as a crawler crane, so that the suspension load is greatly reduced. Unlike cranes mounted on trolleys, they are not subject to suspension loads due to their low head. Furthermore, since the hanging part 30 of the crane 14 includes a U-shaped concave part 20 and can be translated in the vertical and horizontal directions on the carriage part 12, as shown in FIG. A large load can be suspended with a part of the load submerged. Therefore, the mobile crane carrier 10 for low altitude according to the embodiment of the present invention can handle a large load stably as compared with the case where the conventional crane carrier is used in a low sky environment. This can contribute to shortening the construction period.

  Further, as shown in FIG. 1, the low-air mobile crane carrier 10 includes a crane 14 having two hoist type suspension parts 30. The hoist type suspending portion 30 realizes the same suspending ability while being small in size as compared with a normal winch. Therefore, by providing two such hoist type suspension parts 30, it is possible to realize a lifting load necessary for construction while achieving space saving corresponding to a low head environment. Furthermore, since the two suspension parts 30 can be operated synchronously, for example, the position adjustment of the load suspended by the two suspension parts 30 can be performed efficiently while maintaining a balance.

  Further, in the low-air mobile crane carrier 10 according to the embodiment of the present invention, the carrier portion 12 is composed of a plurality of assembly carrier vessels, and depending on the combination of the plurality of assembly carrier vessels, the carrier vessel The shape and size of the portion 12 can be changed. For example, when there is another structure around the construction object, the low-crane mobile crane carrier 10 is moored at a position where work can be performed on the construction object without receiving interference from another structure. The base boat part 12 is configured in such a shape that can be used (see FIGS. 5 to 9). Thus, work can be efficiently performed by flexibly corresponding to the size of the construction target and the surrounding environment. Furthermore, if the trolley part 12 of the mobile crane carrier 10 for low altitude is divided into a plurality of assembly crafts, it will be transported near the construction site. Regardless, it can be easily transported.

  On the other hand, the steel temporary closing installation method according to the embodiment of the present invention uses two low-air mobile crane carriers 10 as shown in FIG. 1 in a low-head environment as shown in FIG. A steel temporary deadline is installed around the structure. As shown in FIG. 2, the steel temporary closing installation method includes a loading step S <b> 20 for loading a member for forming a steel temporary cutoff into a low-air mobile crane carrier 10, and a low-air mobile crane carrier 10. Including a mooring step S30 for mooring a steel temporary deadline, a forming step S40 for forming a steel temporary deadline, and a setting step S50 for setting a steel temporary deadline. Furthermore, the example of FIG. 2 includes a floor excavation step S10 that is performed prior to the other steps described above.

  The floor excavation step S10 is a step of removing earth and sand around the structure until at least a part of the foundation of the structure to be constructed, for example, the upper end surface of the foundation is exposed in water. More specifically, as shown in FIG. 3, the sand pump 74 is submerged from the work ship 76 in the surrounding underwater sand of the pier 72 that is a construction target structure, and the sand ship 74 is used to carry the sand carrier 78. The soil around the pier 72 is removed by sucking up the soil. As a result, even if the foundation 72a of the pier 72 is buried in the underwater sediment, by removing the sediment around the pier 72 in the floor excavation step S10, the subsequent steps can be performed more reliably. It becomes possible to sink a steel temporary cutoff on the foundation 72a.

  Subsequently, in the loading step S20, as shown in FIG. 4, as a member for forming the steel temporary cutoff, the divided temporary cutoff 60 having a shape obtained by dividing the cylindrical body into two in the radial direction is divided into two low spaces. It loads in each of the mobile crane carrier ships 10A and 10B. At this time, in each of the low-air mobile crane carrier boats 10A and 10B, the crane 14 loads the divided temporary deadline 60 in the recessed portion 20 of the U-shaped carrier vessel 12 in a suspended state. As a result, even if the size of the divisional provisional deadline 60 is larger than the height of the crane 14 corresponding to the low head, the part is submerged by being lifted in the recessed portion 20 where the water surface is exposed. The divisional provisional deadline 60 can be lifted.

  In the mooring step S30, as shown in FIG. 8, the pier 72A to be constructed is sandwiched between the U-shaped concave portions 20 of the two low-air mobile crane carriers 10A and 10B. Two low-climbing mobile crane carrier ships 10A and 10B are moored at the position. That is, the protrusions 22 located on both sides of the recess 20 of the carriage 12 are moored at a position where the bridge pier 72A is sandwiched between the recesses 20 in such a manner that the low-air mobile crane carriers 10A and 10B abut each other. At this time, as shown in FIG. 5 to FIG. 7, two low-air mobile devices are used while adjusting the position by using winches 50 and spuds provided in the low-air mobile crane carriers 10 </ b> A and 10 </ b> B. The crane carrier 10A, 10B is moored.

  Then, in the forming step S40, as shown in FIG. 9, the position of the two divided temporary deadlines 60 suspended by the two moored low-air mobile crane carriers 10A and 10B is lifted by the crane 14. Combine while adjusting. As can be confirmed in FIG. 4B, each of the divided temporary deadlines 60 has a shape in which the cylindrical body is divided into two in the radial direction, so that the divided surfaces 60a face each other so as to sandwich the pier 72A. Thereby, the cylindrical steel temporary cutoff 62 surrounding the pier 72A is formed.

  Further, in the setting step S50, the formed cylindrical steel temporary cutoff line 62 is brought into the water by adjusting the position and angle with respect to the pier 72A by the cranes of the two low-air mobile crane carriers 10A and 10B. By sinking, it is set around the pier 72A. More specifically, in the setting step S50 of FIG. 2, it is first determined whether or not there is a steel temporary cutoff 62 that has been set around the pier 72A (S52). And, as shown in FIG. 10, when there is no steel temporary deadline 62 already set around the pier 72A, such as installing the first steel temporary deadline 62A for the pier 72A to be constructed. As shown in FIG. 11, a steel temporary cutoff 62A is set on the foundation 72a of the pier 72A (first setting step S54). On the foundation 72a of the pier 72A, a receiving surface 72b of the steel temporary cutoff 62A may be formed in advance with underwater concrete or the like.

  On the other hand, as shown in FIG. 12 (FIG. 14), a steel temporary cutoff 62A that has already been set around the bridge pier 72A such that a second steel temporary cutoff 62B (62C) is installed on the pier 72A. If there is (62B), as shown in FIG. 13 (FIG. 15), the new steel to be installed this time so as to be stacked in the cylindrical axial direction on the already-set steel temporary cutoff 62A (62B). The provisional deadline 62B (62C) is set (second setting step S56). Thereafter, the steel temporary cutoff 62A (62B) that has already been set up and the steel temporary cutoff 62B (62C) that has been set up this time are joined together with the cylindrical end faces thereof, and the cylindrical steel that is longer in the depth direction. A provisional deadline is formed (joining step S58).

Then, the loading step S20, the mooring step S30, the forming step S40, and the settling step S50 described above are performed until the upper end of the uppermost steel temporary deadline 62 is at a height where it comes out on the water as shown in FIG. By repeating, the cylindrical steel temporary cutoff 62D which has the length which reaches from the foundation 72a of the pier 72A to the surface of the water is formed around the pier 72A.
Therefore, the steel temporary closing installation method according to the embodiment of the present invention is a low altitude mobile type even when the steel temporary closing 62D is installed on the pier 72A where the foundation 72a is submerged to a deep position. Cylindrical steel cutoffs 62A, 62B, 62C of a size that can be handled by the crane carrier 10 are stacked in the axial direction to extend from the foundation 72a of the pier 72A to the surface of the water. The steel temporary cut-off 62D having a sufficient length to form the can be efficiently installed in a low head environment.

  Further, when forming the cylindrical steel temporary cutoff 62 (62A, 62B, 62C) from the divided temporary cutoff 60 having a shape obtained by dividing the cylindrical body into two in the radial direction, it is a joining operation between the divided surfaces 60a. It is possible to reduce the joining work of the divisional temporary deadline 60 and contribute to shortening the construction period. Furthermore, even if the divided temporary deadline 60 is composed of a plurality of smaller steel members or the like, if the divided temporary deadline 60 is configured in advance in the state of the divided temporary deadline 60 described above, the steel temporary deadline 62 is provided. The installation cost is reduced, and the cost can be reduced. Further, since the divided temporary deadline 60 and the steel temporary deadline 62 are lifted by the crane 14 of the low-air mobile crane carrier 10, it is not necessary to install temporary materials such as a hanging jig on the pier 72A to be constructed.

  Moreover, in mooring process S30, as shown with the code | symbol 24 in FIG. 8, you may rigidly connect the front-end | tips of the protrusion 22 of the two low-air mobile crane carrier 10A, 10B. Then, as shown in FIG. 10 (FIGS. 12 and 14), in the setting step S50, two low-air mobile crane carriers 10A and 10B at a substantially line-symmetrical position around the pier 72A in plan view. The steel temporary cutoff 62A (62B, 62C) is sunk from the state where the steel temporary cutoff 62A (62B, 62C) is lifted in a well-balanced state by the crane 14. At this time, as shown in FIG. 11 (FIGS. 13 and 15), the steel temporary cutoff 62A (62B, 62C) suspended by the crane 14 settles down and the load of the steel temporary cutoff 62A (62B, 62C) is reached. After the loss, the weight of the ballast water in the ballast tank 55 that has kept the balance between the low-flying mobile crane carriages 10A and 10B is rigidly connected as indicated by reference numeral 24. The two low-flying mobile crane carrier boats 10A and 10B are shared like a single carrier vessel. Thus, the weight of the ballast water in the ballast tank 55 of the carriage 10A and the weight of the ballast water in the ballast tank 55 of the carriage 10B are orthogonal to the line segment passing through the rigid position 24 in plan view ( Since it is balanced in the left-right direction in the figure, it is possible to prevent inclination in a direction perpendicular to the line segment of the low-air mobile crane carrier 10A, 10B.

  On the other hand, the inclination in the line segment direction (perpendicular to the plane of the drawing in the drawing) passing through the rigid position 24 in a plan view of the low altitude mobile crane carrier 10A, 10B lifted the steel temporary cutoff 62A (62B, 62C). Although it depends on the position in the line segment direction, it is smaller than the inclination in the direction perpendicular to the line segment, which has been a concern, and is slightly inclined. Accordingly, it is possible to prevent the crane 14 from coming into contact with the bridge girder 70 even immediately after the load of the steel temporary cutoff 62A (62B, 62C) lifted by the low-air mobile crane carrier 10A, 10B is lost. It becomes possible. In addition, the inclination of the base boats 10A, 10B immediately after the landing of the steel temporary cutoff 62A (62B, 62C) without the rigid ends of the protrusions 22 of the low-air mobile crane base boats 10A, 10B being rigidly connected. However, when the crane 14 is small enough not to contact the bridge girder 70, the anchoring step S30 may be performed without setting the tips of the protrusions 22 rigidly.

  Furthermore, in the steel temporary deadline installation method according to the embodiment of the present invention, when the position of the divided temporary deadline 60 is adjusted as shown in FIG. When the position of the steel temporary cut-off 62 (62A, 62B, 62C) is adjusted as shown in FIGS. By synchronously operating the four suspension parts 30 in total for the type crane carriages 10A and 10B, the position adjustment of the divided temporary deadline 60 and the steel temporary deadline 62 can be performed efficiently while maintaining a balance. Moreover, as shown in FIGS. 9-15, work is advanced efficiently by using the low-air mobile crane carrier 10A, 10B as a water scaffold for forming and installing the steel temporary cutoff 62. It becomes possible.

  Referring again to the low-air mobile crane carrier 10 according to the embodiment of the present invention, the low-air mobile crane carrier 10 includes a U-shaped carrier 12 as shown in FIG. It is used by one set of two in a mode in which the construction target position such as the submerged bridge pier 72A is sandwiched by the recess 20. The two low-lift mobile crane carriers 10A and 10B have protrusions 22 located on both sides of the concave portion 20 of the carrier portion 12 depending on the construction contents. It may be close to the contact position or may be moored at a slightly spaced position. By using the two low-crane mobile cranes 10A and 10B cranes 14A and 10B arranged in this way individually or in combination, it is possible to easily install and pull up the members surrounding the pier 72A. Can do.

  Furthermore, the low-air mobile crane carrier 10 forms a dry-up space DS around the pier 72A as shown in FIG. 16 as well as a water scaffold for forming and installing the steel temporary cutoff 62. After that, it can be used as a water scaffold for subsequent work. If the unic 58 for material loading is provided on the carriage 12, the necessary materials on the carriage 12 when the low-air mobile crane carriages 10 </ b> A and 10 </ b> B are constructed as floating scaffolds. Can be efficiently loaded and the construction period can be further shortened.

  10 (10A, 10B): Mobile crane carrier for low altitude, 12: carrier ship, 14: crane, 20: recess, 22: protrusion, 30: suspension, 36: traveling rail, 58: unic, 60: Divided provisional deadline, 62, 62A, 62B, 62C, 62D: Steel temporary deadline, 72, 72A, 72B: Pier (structure), 72a: Foundation, H: Crane height

Claims (15)

In order to form a cylindrical dry-up space around a structure that is at least partially submerged in a low-headed environment, two low-level mobile crane carriers are used to surround the structure. It is a steel temporary deadline installation method for setting a steel temporary deadline so as to surround,
The low-altitude mobile crane carrier is a U-shaped carrier that extends in a vertical direction and a horizontal direction in plan view, and a crane that is installed on the carrier and has a height corresponding to a low head. The crane is provided with a suspension part that can move in parallel in the vertical direction and the horizontal direction on the base boat part. A loading step of loading a split provisional deadline having a shape obtained by dividing a cylindrical shape into two in the radial direction in the state of being lifted by the crane at the U-shaped recess in each of the two low-flying mobile crane carriages When,
A mooring step of mooring the two low-flying mobile crane carriages at a position where the structure is sandwiched between the recesses;
A step of forming a cylindrical steel temporary cutoff by connecting the divided temporary cutoffs so as to surround the structure while adjusting the position of the divided temporary cutoff by the crane;
The steel temporary closing installation method according to claim 1, further comprising: a sinking step of sinking the temporary steel cutoff around the structure while adjusting the position by the crane. In the setting step, if there is no steel temporary deadline already set, the steel temporary deadline is set on the foundation of the structure, and if there is the steel temporary deadline already set, After laying the steel temporary deadline so as to be stacked on the steel temporary deadline, the steel temporary deadlines that have been laid are joined together,
The loading step, the mooring step, the forming step, and the laying step are repeated until the upper end of the uppermost steel temporary deadline that has been laid becomes a height at which the upper end comes out on the water. Item 3. The steel temporary deadline installation method according to item 2.   4. The temporary steel installation according to claim 2, wherein, in the mooring step, the ends of the U-shaped protrusions of the two low-aircraft mobile crane carriers are rigidly connected to each other. 5. Construction method. Two hanging parts are provided on the crane of the low-air mobile crane carrier,
5. The steel temporary closing installation method according to claim 1, wherein, in each step, the two suspension portions are operated synchronously as necessary.   The steel temporary closing installation method according to claim 5, wherein, in the forming step and the setting step, a total of the four suspension parts of the two crane carriers are operated synchronously as necessary. . The base boat part of the low-air mobile crane base boat is constituted by a plurality of assembly base boats,
7. The size of the barge part is changed by changing the combination of the assembly boats according to the size of the structure and the surrounding environment of the structure. The steel temporary deadline installation method described in item 1.   The temporary steel making process according to any one of claims 1 to 7, further comprising a floor excavation step of removing earth and sand around the structure until at least a part of the foundation of the structure is exposed in water. Deadline installation method. A low-flying mobile crane carrier used for construction on the water or underwater, including lifting work in a low-altitude environment,
A U-shaped base boat part extending in the vertical direction and the horizontal direction in plan view, and a crane installed on the base ship part and having a height corresponding to a low head,
The crane is provided with a suspension part that can move in parallel in the vertical direction and the horizontal direction on the carriage part, and is installed in parallel and extends to each of the U-shaped protrusions. A low-flying mobile crane carrier characterized by being an overhead crane with rails .   The mobile crane carrier for low altitude according to claim 9, wherein the construction target position is sandwiched between the U-shaped concave portions and used as a set of two.   The mobile crane carrier for low altitude according to claim 10, wherein the ends of the U-shaped protrusions are rigidly connected between two. The low-crane mobile crane carrier according to any one of claims 9 to 11 , wherein the crane includes two hoist-type suspension parts. The mobile crane carrier for low altitude according to claim 12 , wherein the two suspension parts can be operated synchronously. It said platform ship section is constituted by a plurality of assembly barge, according to the combination of the plurality of assembled barge, claim 9, wherein 13 of the shape of the base ship section is changeable The low-air mobile crane carrier according to item 1. The low-crane mobile crane carrier according to any one of claims 9 to 14 , further comprising a unic for material loading on the carrier portion.

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