JPS6130093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing gravity-type structures such as concrete caissons and blocks.
This type of structure is used for port construction, seawall construction, and as the foundation for offshore oil field bases, and is manufactured by assembling a box stand and formwork inside a dock and then pouring concrete into it. However, although such structures are strong against compressive loads, they are vulnerable to external impacts and seawater. In particular, the seabed near oil fields is home to various undesirable substances, including sulfur, which poses a serious problem. Recently, however, structures have begun to appear in which the outer surface of the structure is covered with a metal plate and this surface is painted. However, the anti-rust and anti-corrosion effect of painting has a short service life, and metal plates are eventually subject to corrosion. Furthermore, metal plates with high thermal conductivity cause large temperature changes in underwater structures, and are considered undesirable.

On the other hand, several problems have been pointed out in the past when manufacturing this type of structure. First, there is adhesion between the floor of the box stand and the bottom of the structure. Conventionally, to prevent this, people have laid down Hatron paper or asphalt paper, but it has not been as effective as expected due to rain and concrete hardening heat. Second, when removing the formwork, excessive force may be applied to the structure, causing cracks and deformation. Thirdly, there is the problem of cracks and deformation due to the weight of the completed structure when it is lifted.

The present invention has been made in an effort to provide a method for manufacturing a structure that overcomes these drawbacks. Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a concrete caisson according to the present invention. A cavity 2 for ballast water is formed in the caisson 1, and the outer surface is covered with a panel 3 of F.R.P. The caisson 1 is manufactured by pouring concrete, but when used in areas with large temperature changes, the outer surface of the concrete may be covered with foamed concrete for heat retention, making it double-layered. In this case, the F.R.P panel 3 also plays the role of protecting the heat insulating material. For the bottom plate, F.R.P panel 3 is used for the sake of caisson manufacturing, but uncured F.R.P may be applied to the side surfaces after the caisson is manufactured. When the caisson 1 is small in size, each side is constructed with one panel, and in the case of a large caisson, multiple panels are used as shown in the figure. If necessary, install panel 3 on the inner surface of cavity 2.
However, if the vertical dimension of the caisson is large and it protrudes above the sea surface, the floor will be formed on the top of the caisson, so it will be easy to cover the entire floor with panels. When connecting the panels 3, as shown in FIGS. 2A and 2B, they are fastened with bolts 5 and nuts 6 with seals 4 interposed. This seal 4 prevents concrete from leaking outside when the caisson 1 is manufactured, and prevents seawater from entering after the caisson 1 is installed on the seabed.

The F/R/P panel 3 has flexibility and can absorb external impact to some extent, but if the impact is large, there is a risk that the panel 3 and the concrete layer will separate. For this reason, as will be described later, reinforcing bars and anchors are connected to the inner surface of the panel 3, and these are embedded in the concrete layer. FIG. 3 shows an example of reinforcing bars, in which ribs 7 are provided at a plurality of locations on the inner surface of the panel 3, and rings (or hooks) 8 are attached to the holes 7a of each rib. The reinforcing bars 9 are rectangular and connected to the panel 3 by respective rings 8.
The reinforcing bar shape shown in the figure is just an example, and various shapes may be considered. FIGS. 4 and 5 are examples of using anchors. If the anchor 10 remains as it is, the head will protrude to the outside, so a recess must be formed in the panel 3. Particularly in the case of a bottom panel, this is essential because the caisson load concentrates on the anchor 10 and destroys its head. Furthermore, since holes are to be made in the panel 3, the sealing effect must also be taken into consideration. As will be described later, the separator reinforcing bars are buried in the side of caisson 1, so the above-mentioned consideration is not necessary. However, if the number of reinforcing bars is small, it may be used in combination with the ones in Figures 3 and 4. good.

Next, the manufacturing order of this caisson will be explained. 6th
The figure shows the overall view in a simplified manner, and the F/R/P panel 3 for the bottom plate is placed on the floor surface of the box stand 11. The reinforcing bars 9 are then connected to the rings 8 of the panel. Of course, the reinforcing bars 9 and anchors 10 are attached to panel 3 in advance.
It would be more convenient to have it installed. Next, the formwork was assembled, and this part is shown enlarged in Figure 7. The structure shown in Figure 7 is generally called a separator.
The thickness of concrete can be adjusted accordingly. This is 2
two presser plates 12, a plurality of bars 1 passing through both plates
3. Consists of a support member 14 that supports the presser plate from the outside, and an adjustment nut 15. The holding plate 12 is normally a wooden board, but in the present invention, the outer surface side of the caisson is replaced with an F/R/P panel. Of course, if the inner surface of the cavity of the caisson is also coated with F.R.P., both panels may be made of F.R.P panels. The bar 13 is threaded, and the retaining plate 12 is secured by a nut 15.
The spacing can be adjusted. The support member 14 is made by combining a plurality of square pieces, and looks like FIG. 8 when viewed from the front. Then, concrete is poured between the panel 3 and the holding plate 12, and after hardening, the separator members are removed, leaving the panel 3 and the bar 13. The protruding portion of the bar 13 is cut off,
The buried portion will be reinforced with reinforcing steel. Since the tapered bushing 16 is fixed to the presser plate 12,
When this is removed, a depression is created on the outer surface of the caisson, from which the bar 13 protrudes. Therefore, by cutting out the bar 13 within the recess and backfilling with filler, the surface of the caisson can be finished neatly. On the other hand, since the panel 3 side is integrated with the caisson, removing the bar 13 requires some ingenuity. FIG. 9 shows an example, in which a concave-shaped bush 17 is provided in advance on the panel 3, and after the bar 13 is removed, it is closed with an F.R.P. cap 18, or an uncured F.R.P. This is a method of packing.

As described above, according to the manufacturing method of the present invention, it is possible to prevent adhesion between the structure and the formwork, and to obtain a corrosion-resistant structure with excellent adhesion between the panel and the caisson.

[Brief explanation of the drawing]

Figure 1 is a plan view of the concrete caisson of the present invention, Figures 2A and B are enlarged views showing the seal structure between panels, Figure 3 is a perspective view showing the connection state of the panels and reinforcing bars, and Figure 4 is with anchors. Perspective view of the panel,
Fig. 5 is an enlarged sectional view of the anchor portion, Fig. 6 is a sectional view showing the manufacturing method of the present invention, Fig. 7 is a sectional view of the separator, Fig. 8 is a front view of the support member, and Fig. 9 is a sectional view of the bushing. It is an enlarged sectional view. 1... Concrete caisson, 2... Cavity, 3...
F・R・P panel, 4...Seal, 7...Rib, 9...
Reinforcing bar, 10... Anchor, 11... Box stand, 12... Holding plate, 13... Bar, 14... Supporting member, 17... Bush.

Claims (1)

[Claims] 1. When manufacturing a gravity-type structure such as a concrete caisson or block, first a corrosion-resistant panel is placed on the floor of a box stand,
Attach reinforcing bars or anchors to the inner surface of this panel,
Next, when assembling the formwork for the side of the structure, at least the outer panel of the separator is formed with a corrosion-resistant panel, concrete is poured into the formwork and solidified, and the bars of the separator are buried, and then the formwork other than the panels is assembled. A method for manufacturing a gravity-type structure, the method comprising removing members. 2. The method for manufacturing a gravity type structure according to claim 1, wherein the corrosion-resistant layer is a F.R.P panel. 3. The method for manufacturing a gravity type structure according to claim 2, wherein the reinforcing bars are connected to ribs on the inner surface of the F.R.P panel. 4. The method for manufacturing a gravity type structure according to claim 2, wherein the anchor projects inside the F.R.P. panel.