JP2005030007A - Floating box body construction method and floating box body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a floating box body construction method capable of simplifying a structure of a floating box body, and the floating box body. <P>SOLUTION: A box body 1A is formed, and a stud dowel 5 and a reinforcement 3 are arranged on the outer periphery. The box body 1A is enclosed by a form 9a for a bottom plate 1b, and a form 9b for both side side plates 1c and a floorboard 1a, and after injecting liquid (q)becoming a counterweight by a proper quantity into the box body 1A, concrete is placed between the box body 1A and the forms 9a and 9b. A filling degree detecting sensor 16 is prearranged between the box body 1A and the forms 9a and 9b, to detect a filling degree in respective parts of a concrete placing area. The liquid (q) is further injected into the box body 1A in parallel to placing work of the concrete, and the liquid level height h<SB>2</SB>of this liquid (q) is successively heightened in response to the rise of the concrete placing height h<SB>1</SB>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for constructing a floating body of a steel plate / concrete composite structure (hereinafter referred to as “hybrid structure”) suitable for a floating pier, a breakwater, and the like, and the floating body.
[0002]
[Prior art]
In general, a floating structure having a structure as shown in Patent Document 1 described later is used for a floating jetty installed on a quay or the like. Hereinafter, this floating body will be described with reference to FIGS.
As shown in FIG. 5, the floating body 10 is formed in a hollow rectangular parallelepiped shape by the steel plate 1. The floating body 10 has a box 1A provided with a plurality of cross girders 8 and a plurality of vertical ribs 4 connecting the cross girders 8 on the inner wall for reinforcement, and is hitting the outer periphery of the steel plate 1. It is comprised in the hybrid structure which consists of the provided concrete surface layer part 2. FIG. Here, a large number of stud dowels 5 and reinforcing bars 3 are arranged on the outer surface of the steel plate 1 (box 1A), and the concrete surface layer portion 2 is placed so as to embed these stud dowels 5 and reinforcing bars 3. And integrated with the box 1A.
[0003]
Conventionally, the floating body 10 having such a structure is constructed according to the procedure shown in FIGS.
That is, first, a hollow rectangular parallelepiped steel plate box 1A composed of a floor plate 1a, a bottom plate 1b, and both side plates 1c is formed, and a large number of stud dowels 5 are infused on the outer surface of the box 1A. A plurality of concrete-made support bases 11 are attached to the outer surface of (Fig. 6 (a)).
Next, after temporarily placing the box 1A on the gantry 7, a plurality of reinforcing bars 3a are arranged so as to surround the outer periphery of the bottom plate 1b of the box 1A and the lower outer periphery of the side plates 1c, Arrange the outside. (FIG. 6B).
Further, after placing the box 1A with the reinforcing bars 3a in this way on the base 15 on which the formwork 9a for the bottom plate 1b has been laid in advance via the support base 11 (FIG. 6 (c)). Then, a plurality of reinforcing bars 3b are arranged so as to surround the upper outer periphery of the side plate 1c and the outer periphery of the bottom plate 1b of the box 1A (FIG. 6 (d)).
Then, the both side plates 1c of the box 1A and the mold 9b for the floor board 1a are assembled (FIG. 6 (e)), and then concrete is placed on the outer periphery of the box 1A to form the concrete surface layer portion 2. Thus, the floating body 10 having a hybrid structure is completed (FIG. 6F).
[0004]
[Patent Document 1]
Japanese Patent No. 3322252 (paragraphs 0009 to 0015 and FIGS. 1 and 4)
[0005]
[Problems to be solved by the invention]
The construction method of the floating structure 10 having such a hybrid structure has the following problems.
That is, when constructing the floating body 10, as shown in FIG. 7, when concrete is placed between the molds 9 a and 9 b and the outer periphery of the box 1 A, the weight of the placed concrete is reduced to that of the box 1 A. An external pressure is applied to the bottom plate 1b and both side plates lc, and acts to indent the bottom plate 1b and both side plates lc inward as shown by broken lines in the figure.
If the concrete is hardened in a state where such a box is deformed, the dimensional accuracy of the box 10 as a product is deteriorated.
[0006]
Conventionally, as shown in FIG. 5, the deformation due to the external pressure of the concrete is such that a plurality of cross beams 8 are spaced from the inner wall of the box 1 </ b> A, and the cross beams 8 are connected to a plurality of vertical ribs 4. It is restrained with a structure that is reinforced by connecting with.
However, the box 1A has sufficient rigidity even after the concrete surface layer portion 2 is formed (after the concrete is hardened) without the vertical rib 4, and the vertical rib 4 is excessive after the concrete is placed. Since it becomes a (unnecessary) reinforcing material, the manufacturing cost of the floating body 10 increases accordingly. In addition, when filling the bottom slab part with concrete, the bottom slab concrete acts as a hydraulic pressure, and the box 1A in FIG. 5 is lifted by the lifting pressure. Therefore, in the bottom slab concrete filling in FIG. It was necessary to manage the placement height in response to fluctuations in lifting pressure.
[0007]
This invention is made | formed in view of such a situation, Comprising: It aims at providing the construction method and the floating body of a floating body which can simplify the structure of a floating body.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the method for building a floating body of the present invention employs the following means.
That is, the method for building a floating body according to the present invention is a method for building a floating structure with a hybrid structure in which a concrete surface layer is formed on the outer periphery of the box, and concrete is placed on the outer periphery of the box. Then, when forming the concrete surface layer, a liquid is injected into the box in parallel with the concrete placing work, and the liquid level of the liquid is increased to the concrete placing height. It is characterized by the fact that it is gradually raised together.
[0009]
In this floating box construction method, when concrete is placed on the outer periphery of the box, liquid is injected into the box. Then, the pressure of the liquid is applied to the inner surface of the box, and the box is pressed from the inside toward the outside.
Since the pressure of the liquid acts on the inner surface of the box in this way, the pressure of the concrete applied to the box from the outside is offset, so that deformation that occurs in the box is reduced. Since the amount of liquid injected into the box increases as the concrete placement position increases, the internal pressure applied to the box also increases sequentially, and the concrete pouring progresses and the concrete pressure increases. Even if sequentially increases, the internal pressure applied to the box is always maintained at the same level as the concrete pressure applied to the box, and these are offset, and the shape accuracy of the box is maintained with high accuracy.
Moreover, by injecting the liquid into the box in this way, the liquid becomes a weight of the box, and the hydraulic pressure (lifting pressure) at the time of placing the bottom slab concrete can be canceled.
[0010]
In this floating body construction method, a filling level detection sensor for detecting a filling state of the placed concrete is used, and the liquid level height of the liquid is determined based on the filling state of the concrete detected by the filling degree detection sensor. You may control.
In this case, since the worker can accurately grasp the concrete filling state based on the measurement value of the filling degree detection sensor, the liquid level of the liquid can be controlled better, and the box Concrete can be placed while effectively suppressing deformation.
[0011]
Further, the floating body according to the present invention is a floating structure having a hybrid structure in which a concrete surface layer portion is formed on the outer periphery of the box, and is formed by using the above-described floating body construction method. It is characterized by being.
The floating body constructed in this way requires vertical ribs to prevent deformation of the box during construction in the conventional floating body. By injecting liquid into the box, Since the concrete cover is formed around the box in a state where deformation is prevented, the vertical rib can be eliminated. Therefore, the floating body according to the present invention realizes a configuration in which the reinforcing member necessary only during construction is eliminated while maintaining the shape accuracy of the box.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 3, a floating body 10A according to the present invention includes a box 1A formed into a hollow rectangular parallelepiped shape by a steel plate 1, and a number of studs disposed on the outer surface of the steel plate 1 (box 1A). A hybrid structure is formed by the gibber 5 and the reinforcing bar 3 and the concrete surface layer portion 2 placed on the outer periphery of the steel plate 1 so as to embed the stud gibber 5 and the reinforcing bar 3.
[0013]
As shown in FIGS. 1 and 2, a box 1A is a hollow rectangular parallelepiped composed of a floor plate 1a, a bottom plate 1b disposed oppositely below the floor plate 1a, and both side plates 1c connecting the floor plate 1a and the bottom plate 1b. It has a shape.
Further, as shown in FIG. 3, a plurality of cross beams 8 substantially parallel to the vertical surface are provided on the inner wall of the box 1A at intervals in the horizontal direction. These cross beams 8 are provided so as to go around the inner wall surface of the box 1A.
[0014]
Hereinafter, a construction method of the floating body configured as described above will be described.
The floating body construction method according to the present invention is characterized in that in the conventional floating body construction method, the main feature of the work when placing concrete on the outer periphery of the box is as follows. The same technique as that of the conventional construction method can be used until the step of placing, that is, the steps shown in FIGS. 6A to 6E.
[0015]
Specifically, first, the box 1A is formed in the same manner as the conventional floating box construction method, and the stud gibber 5 and the reinforcing bar 3 are installed on the outer periphery thereof. The box 1A may be formed using the steel plate 1 on which the stud gibber 5 has been previously grown.
Subsequently, the box 1A is surrounded by the mold 9a for the bottom plate 1b, the side plates 1c, and the mold 9b for the floor board 1a, and after a suitable amount of liquid q serving as a counterweight is injected into the box 1A, the box 1A is filled. Concrete is placed between the molds 9a and 9b (see FIG. 1).
For example, water or seawater is used as the liquid q serving as the counterweight, and high-fluidity concrete is used as the concrete that covers the periphery of the bottom plate 1b. Moreover, although normal concrete is used as concrete which covers the both-sides board 1c and the floor board 1a, you may use not only this but high fluidity concrete.
[0016]
Here, prior to the concrete placing work, a filling degree detection sensor 16 for detecting the filling state of the concrete is provided in advance between the box 1A and the molds 9a and 9b (see FIG. 4). The filling degree detection sensors 16 are installed at a plurality of locations so as to detect the filling degree in each part of the concrete placing region.
For example, an electrical resistance sensor is used as the filling degree detection sensor 16. The electrical resistance sensor has, for example, measurement terminals that are exposed and spaced apart from each other, and each measurement terminal is connected to a measurement device (not shown) via a lead wire 17. The measuring device measures the electric resistance between the measuring terminals, and when the concrete is completely filled around the measuring terminals, the measuring terminals conduct and the measured value of the electric resistance becomes zero. Therefore, the concrete filling state in the vicinity of the sensor can be known from the measured value of electric resistance.
[0017]
In the present embodiment, as shown in FIG. 4, as the filling degree detection sensor 16, the position of the box 1A in the width direction is changed between the bottom plate 1b of the box 1A and the mold 9a for the bottom plate 1b. Three sensors of filling degree detection sensors 16a, 16b, and 16c are provided. The filling degree and concrete設高of h ₁ of the concrete which is Da設between the sides plates 1c and floor plate 1a and the mold 9b is worker measured using a height measuring rod, not shown.
[0018]
Then, while sequentially measuring the filling state and striking設高of h ₁ of the concrete by measurement using the measurement and the height measurement rod filling degree detection sensor 16, performs striking設作industry concrete. By pouring concrete in this manner, external pressure P ₁ is applied to the box body 1A (see FIG. 1).
In parallel with striking設作industry this concrete, further injecting a liquid q in box body 1A, sequentially increasing the combined liquid level height h ₂ of the liquid q to increase the concrete設高of h ₁ Go (see Figure 2). Here, liquid level height h ₂ of the liquid q is performed by a water level measuring rods or other water level measuring device, for example, not shown.
[0019]
When the liquid q is injected into the box body 1A so, pressure is applied P ₂ of the liquid q on the inner surface of the box body 1A, the box body 1A is pushed toward the inside to the outside.
By thus acting pressure P ₂ of the liquid q on the inner surface of the box body. 1A, offset the pressure P ₁ of the concrete applied from the outside to the box body 1A.
The amount of liquid q injected into the interior of the box body 1A is, to increase as the pouring position of the concrete is increased, thereby it will be increased successively also internal pressure P ₂ applied to a box body 1A, pouring concrete progress be increased pressure P ₁ of the concrete sequentially by, the internal pressure P ₂ applied to the box body 1A is these are offset is always maintained at the same level as the pressure P ₁ of the concrete acting on the box body 1A.
For this reason, the concrete placement work is performed in a state in which the shape of the box 1A is always kept good, and the floating body 10A with high shape accuracy can be obtained without providing reinforcing ribs on the box 1A. The construction cost and construction period of the floating body 10A can be significantly reduced.
[0020]
Here, the proper amount of injected liquid q at each time point of the concrete設作industry, for example, by structural calculation or the like internal pressure P ₂ may be determined by calculating the amount equal to the external pressure P _1.
Alternatively, the deformation amount of the box 1A may be measured and the injection amount may be adjusted so that the deformation amount is minimized.
[0021]
And, as described above, the level of the liquid q is controlled based on the detected concrete filling state in a state where the concrete filling state is accurately grasped using the filling degree detection sensor 16 or the like. It is possible to place concrete while controlling the liquid surface height of the liquid q better and effectively suppressing deformation of the box 1A.
Further, the liquid q injected into the box 1A becomes a weight, and the hydraulic pressure (lifting pressure) at the time of placing the bottom slab concrete can be canceled. For this reason, the management required to prevent the box 1A from being lifted during the concrete placing operation, which is necessary in the past, becomes unnecessary, and the manufacture of the box 10A is facilitated.
[0022]
【The invention's effect】
According to this floating box construction method, the internal pressure of the box generated by injecting liquid into the box cancels the pressure of the concrete applied to the box from the outside, so the box is less likely to be deformed. The concrete can be placed while maintaining the shape of the box satisfactorily.
Since the deformation of the box during concrete pouring is suppressed by the liquid pressure in this way, a floating body with high shape accuracy can be obtained without providing vertical ribs for reinforcement on the box. The construction cost and construction period of the box can be greatly reduced.
In addition, since the liquid injected into the box overlaps, the hydraulic pressure (lifting pressure) at the time of placing the bottom slab concrete can be canceled, so management to prevent the box from lifting during the concrete placing work Becomes unnecessary, and the manufacture of the floating body becomes easy.
Further, according to the floating body according to the present invention, since the concrete cover is formed around the box in a state in which the deformation of the box is prevented by the liquid injected into the box, the shape of the box Reinforcing members (vertical ribs) necessary only during the construction of the floating body can be eliminated while maintaining accuracy. Thereby, the construction cost of a floating body can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing one process of a method for building a floating body according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing one process of a method for building a floating body according to an embodiment of the present invention.
FIG. 3 is a longitudinal sectional view showing a structure of a floating body according to an embodiment of the present invention.
FIG. 4 is a diagram showing details of a method for constructing a floating body according to an embodiment of the present invention.
FIG. 5 is a longitudinal sectional view showing a configuration of a conventional floating body.
FIG. 6 is a diagram showing a construction process of a conventional floating body.
FIG. 7 is a diagram showing a case where no vertical rib is provided on the box in the conventional method of building a floating box.
[Explanation of symbols]
1A Box 2 Concrete surface layer 10A Floating body 16a, 16b, 16c Filling degree detection sensor q Liquid

Claims (3)

A method of constructing a floating structure with a hybrid structure in which a concrete surface layer is formed on the outer periphery of the box,
When concrete is placed on the outer periphery of the box to form the concrete surface layer, a liquid is injected into the box in parallel with the concrete pouring work, and the liquid level of the liquid is increased. A method for constructing a floating body, characterized in that the height is gradually increased as the concrete placement height increases. In the construction method of the floating body according to claim 1,
The liquid level of the liquid is controlled based on the filling state of the concrete detected by the filling degree detection sensor using a filling degree detection sensor for detecting the filling state of the placed concrete. How to build a floating body. A floating structure with a hybrid structure in which a concrete surface layer is formed on the outer periphery of the box,
A floating body formed by using the floating body construction method according to claim 1.

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