JPS5843531B2 - Large caisson manufacturing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a large caisson used for quays, breakwaters, offshore working bases, etc., and a floating barge device used for manufacturing the same.

In recent years, the construction water depth of quays and breakwaters has become increasingly large in the construction of various offshore work bases, etc., and it has become necessary to increase the size of caissons.

Traditionally, relatively small caisson caissons were completed at land yards and loaded onto launching carts, or hoisted onto a crane ship and launched into the water.

However, when the caisson becomes larger, the lifting capacity of hydraulic jacks, launching carts, and crane vessels is insufficient due to its weight and planar dimensions, so it must be constructed on a dry dock, sometimes on a purge, or on a floating dock. In this case, it is not necessarily common because it depends on topographical and ground conditions, and the construction cost increases dramatically when the draft when pulling out the caisson increases. Not everything can be completed.

Furthermore, if a large caisson were to be built on an existing launching barge or submerged pull barge, the following drawbacks would be expected.

In other words, when launching a caisson with a launching barge, there is a risk of significant tilting and damage to the barge itself when the water pours down. It is dangerous unless the caissons have excellent resilience.

With submerged pull barges, the moment the barge is submerged in water during launch, it becomes unstable, and there is a risk that the caissons will also move erratically and tilt significantly.

Therefore, considering the dimensions, weight, and construction conditions of the caisson, manufacturing using a floating dock is one of the most promising construction methods for large-scale caissons in the future.

Floating docks are manufactured in large numbers in Japan for relatively medium to small caissons.

As shown in FIGS. 1 and 2, existing floating docks are often characterized by rectangular planes and sides, and concave front surfaces.

In order to prevent the work deck from being submerged in seawater when the caisson is completed, it is normal to ensure at least 0.5 m of freeboard when the maximum load is loaded.In this case, as shown in Figure 3, the hull section The height of the caisson increases in proportion to the weight of the caisson, increasing the amount of steel required to construct the floating dock and increasing construction costs.

Furthermore, as shown in FIG. 4, the height of the caisson above the sea surface becomes large, causing stability problems, and the caisson also oscillates, making workability difficult.

Additionally, when launching a caisson, the amount of water poured into the floating dock becomes significantly large.

Further, there is a problem that two docks cannot be connected in the horizontal axis direction.

This invention was developed to address the above-mentioned problems, and will be explained below with reference to Examples.

In Figures 5 and 6, 1 is floating barge A.
A hull section 2 of the barge (hereinafter referred to as a barge) is a support stand that also serves as a buoyancy body provided at the four corners of the hull section 1, and a crane device 3 is provided on the support stand 2.

The height of the barge hull 1 should be kept to the minimum required structurally to allow the working deck to be immersed in seawater and, if necessary, caisson fixings 4 or slides on the working deck. A stop 5 is provided.

During construction, barge A will be moored at a predetermined position, the lower part of caisson B will be constructed on the working deck of barge A, and then the frame wall will be constructed using a slide-in platform or the like.

As the weight of the caisson B increases, the hull portion 1 sinks and becomes submerged in water.

In that case, the buoyant force of caisson B is applied, so that caisson B can be built to the required height without sinking.

By the way, even if the hull part 1 of the barge is submerged and a part of the caisson B becomes buoyant, as long as the buoyant force of the barge A acts, the contact surfaces of the working deck and the caisson B will remain in close contact.

However, there is a risk that the caisson B may slide horizontally due to unexpected high waves, oscillations with different periods, etc., so as mentioned above, a fixing device 4 consisting of a stopper or a turnbuckle, or an anti-slip device 5 such as a concave-convex key may be provided. .

In addition, in order to ensure the required stability and reduce the amount of steel that constitutes the barge A, the four corners of the hull 1 are provided with the buoyant force so as to obtain the maximum moment of inertia with the same water line area. Support platform 2 for working machines such as cranes
is the provision.

This buoyant body/support platform 2 increases the stability of the integrated structure consisting of caisson B and barge A under construction even after the work deck of barge A is submerged, and also improves the stability of the structure during construction on the submerged pull barge. It becomes possible to eliminate the disadvantages of water.

When launching caisson B, water is poured into the hull 1 to sink barge A and caisson B is pulled out, as shown in Fig. 14.

In addition, when the height of the support platform 2 is reduced, a watertight hatch is provided at the top of the support platform 2 as shown in Fig. 15, and when launching caisson B, the watertight hatch is closed and the watertight hatch is installed at the top of the support platform 2 as shown in Fig. 15. It may be submerged in water.

After launching caisson B, the water in hull section 1 is drained and barge A is floated to prepare for reuse.

By the way, since this barge A has support stands protruding from the four corners, it is also possible to use two barges in series as shown in FIG. 16.

The present invention has the above configuration, and the height of the hull of the floating barge does not increase so much even if the weight of the caisson manufactured on the floating barge increases, and it is possible to prevent the floating barge from becoming extremely large.

Therefore, the amount of steel required to construct a floating barge is significantly reduced, resulting in lower construction costs.

In addition, the height of the caisson above the sea surface can be suppressed to a certain level, increasing the stability of the floating barge, while at the same time reducing the oscillation of the caisson and significantly lengthening the oscillation period, improving work efficiency.

In addition, during the first half of the caisson construction stage, the work deck is in a freeboard state, so the work is similar to that on a conventional floating dock.

After the work deck is submerged in water, the caisson can be constructed using the sliding platform, so there is no problem.

[Brief explanation of drawings]

Figures 1, 2, 3 and 4 are a plan view and an elevation view of a conventional example, Figures 5 and 6 are a plan view and an elevation view of a floating barge according to the present invention, and Figure 7 , Figure 8, Figure 9
10 and 10 are cross-sectional views showing an example of a fixing device and a non-slip device, and FIGS. 11, 12, 13, and 14.
The figure is an elevation view showing an overview of the construction process, and the caisson is shown in cross section. FIGS. 15 and 16 are an elevational view and a plan view showing another embodiment. A...Floating barge, B...Caisson, 1
... Hull part, 2 ... Support stand, 3 ... Crane device, 4 ... Fixing device, 5 ... Anti-slip.

Claims (1)

[Claims] 1. The floating barge is held in a predetermined position, a caisson bottom slab is constructed on the barge, and then a caisson wall is constructed, and as the floating barge sinks, the caisson wall is created while creating buoyancy in the caisson frame. A method for manufacturing a large caisson, which is characterized by constructing a caisson to complete the caisson, and then removing the caisson from a floating barge. 2. A floating barge device for manufacturing large caissons, in which support stands that also serve as buoyant bodies are protruded from the four corners of the barge body, and a crane device, etc. is installed on the support stand.