JPH04235002A - Floating concrete structure having approximately u-shaped cross section and fabrication thereof - Google Patents

Abstract

PURPOSE:To improve unification and workability of work, by a method wherein a prestressed concrete structure is manufactured of an inner and outer frames by a pretension method, a floating concrete structure is suspended by a projected shaft provided by projecting through both end faces and an upside is turned down. CONSTITUTION:An inner frame 3, which is in almost a box type and made of foam styrol, is arranged on a steel sheet bed 2, reinforcing iron rods 4 and rib reinforcing iron rods 5 are arranged on the circumference also of the inner frame 3, a large number of PC steel wires 6 are stretched, those of which are enclosed by an outer frame 7 which is still more higher than the top of the inner frame 3 and a prestressed concrete structure is manufactured (pretension method). A floating concrete structure after cure is suspended by a projected shaft 10 provided in a projected state on the end faces of outer frames 9, 9' comprised by joining to a driving body main body 8 with a bolt and an upside is turned down. A block 15 made of tempered glass is fitted into a hole penetrating trough the bottom of the main frame 8 and an access hole 18 comprised by communicating the block 15 and a hole 16 provided in the surface of a drainboard 13 with each other by a pipe member 17 is provided.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to the manufacture of floating concrete structures, collectively referred to as concrete pontoons (pontoons, pontoons, etc. not intended for transportation) and barges (barges, etc. for transportation purposes). The present invention relates to a method and a floating concrete structure provided with a viewing window for viewing underwater.

0002

[Prior Art] Conventionally, floating concrete structures are constructed using RC
It is a box-shaped cross-section or an inverted U-shaped cross-section of a prestressed concrete structure using post-tensioning construction or on-site construction. In order to obtain concrete with high strength, hard-mixed concrete with a small slump value is used, and by using this type of concrete, in order to obtain solid concrete with no internal air bubbles or slabs, the side wall The team constructs a formwork suitable for carrying the slab, pours concrete into the side walls and then the slab, and performs meticulous concrete pouring by applying vibrations from a vibrator to the concrete to adjust its workability.

0003

[Problem to be solved by the invention] However, in the former RC structure, in order to minimize the width of cracks caused by shrinkage cracks and accidental twisting, it is necessary to change the posture during concrete pouring (with the container facing down). It is a floating concrete structure that floats on the water surface. This has the advantage that the upper surface of the slab exposed above the water surface can be easily covered with weather-resistant tiles (non-slip tiles, etc.), but the center of gravity of the floating concrete structure itself becomes higher, and the ship's side is affected by wave and wind forces.
It was an unstable structure that was easily affected by impact forces and other horizontal forces.

The latter is a prestressed concrete structure that is most suitable for large span structures such as concrete pontoons and verges, and is highly elastic and flexible, making it difficult to crack even under design loads. This results in a floating concrete structure that is less susceptible to adverse effects from material fatigue even when subjected to repeated changes in vertical movement caused by waves on the water surface, but it takes time to cast concrete and it is difficult to make dense concrete. Not only does it have the disadvantage that it is difficult to apply compressive force, but the places where compressive force can be applied are localized.

[0005]Also, although these are widely used for marine development, fish preserves, etc., there was no facility for viewing underwater conditions.

[0006]

[Means for Solving the Problems] Therefore, in order to eliminate the above-mentioned drawbacks, the present invention comprises a substantially box-shaped foamed member as an inner mold frame,
An outer formwork that is one step taller than the top of the inner formwork is erected around the inner formwork, and a prestressed concrete structure is constructed using the pretension method using this inner formwork and the outer formwork. A method for manufacturing a floating concrete structure having a substantially U-shaped cross section, characterized in that the floating concrete structure is lifted up and turned upside down by a protruding shaft protruding from a surface, and a viewing window for looking into the water is provided. The present invention aims to provide a floating concrete structure characterized by the following.

[0007]

[Example] Floating concrete structure of the present invention (weight 1
2t, length 10m, width 2m, height 1m) will be explained based on the drawings.A steel plate bed (2) is placed on a level-adjusted bed (1), and the steel plate bed On top of (2) is a roughly box-shaped inner form made of styrofoam (3
), the main reinforcement (4) and stirrup reinforcement (5) are arranged around the inner formwork (3), and a large number of PC steel wires (6) are placed under tension, and these are placed around the inner formwork (3). ) and surround it with an outer formwork (7) that is one step taller than the top of the wall to create a prestressed concrete structure (pretension method). The floating concrete structure after hardening is lifted up and turned upside down by the protruding shaft (10) protruding from the gable outer formwork (9) (9') formed by bolting to the main body (8). A method for manufacturing a floating concrete structure having a substantially U-shaped cross section, characterized in that a reinforced glass block (15) is fitted into a hole penetrating the bottom of a main body (8), and An object of the present invention is to provide a floating concrete structure characterized by having a viewing window (18) formed by communicating with a window (16) provided on the surface of (13) through a pipe member (17). . In addition, the above-mentioned viewing window may be used as a magnifying glass.

The floating concrete structure that has been launched is a prestressed concrete structure using the pretension method, and by reducing the diameter of the PC steel wires (6) and increasing the number of them, the compressive force that counters the tensile force can be reduced. It can be applied evenly and evenly to the cross section of the member. Prestressing is introduced by the PC steel wire (6) stretched between the outer formwork (9) (9') on both gable sides, and compressive stress is applied to counter the design load, so both gable sides are Even when the parts are lifted using fulcrums, the main frame body (8) is strong against bending moments and is highly elastic and flexible, so no cracks will occur. As a result, the protruding shafts (1
0) can be used to lift and invert the main body (8).

[0009] The size and shape of the tempered glass blocks (15) can be adjusted freely, and they are compatible with concrete. Therefore, each member constituting the viewing window (18) is assembled into the formwork in advance, and various types of viewing windows (18) can be formed at the same time as the concrete for the precursor is poured.

[0010] The position of the protrusion shaft (11) is determined by the outer gable formwork (
9) It may also be the centroid (D) of (9'). In this case, the center of gravity (G) of the floating concrete structure is located above its centroid (D), and the protrusion axes (1
When the main body (8) is lifted using the above-mentioned mechanism 0), a moment to reverse the main body (8) will be naturally applied.

[0011] Furthermore, in order to prevent the inner formwork (3) made of styrofoam from lifting up during concrete pouring, a small beam (11) is installed between the upper beams of the outer formwork (7). Inner formwork floating prevention device (12) that takes the reaction force
You may also set up

[0012] The manufactured floating concrete structure has its opening surface exposed above the water surface and exposes the styrofoam.
15).

[0013]

[Effects of the invention] In a dedicated factory where long spans can be secured, prestressed steel wires are tensioned and multiple floating concrete structures can be manufactured simultaneously between these spans, which is economical and allows for the unification of work. Not only does it improve work efficiency, but the pre-tension method allows the compressive force to be evenly distributed over the cross section of the component, and even if it is a thin PC steel wire, if a large number of them are installed, the circumference of the steel wire will increase. It is advantageous because it becomes more integrated with the concrete. Furthermore, the weight can be reduced by reducing the thickness of the main body member. The floating concrete structure is manufactured in an inverted U-shape, and the product is made by inverting the floating concrete structure without causing any damage to the lifting body, so it can be implemented using existing simple equipment. Compared to conventional inverted U-shaped products, the center of gravity is lowered and there are no attachments to ensure stability, reducing management and maintenance costs. While incorporating the construction method of high-strength, high-density prestressed concrete and the construction method of concrete that does not have defects such as bubbles and slabs, we have created a floating concrete structure with a roughly U-shaped cross section that is optimal and high quality as a floating object on the water surface. This has a great effect in that it can be finally supplied. Additionally, if a viewing window is provided, the floating concrete structure can be used to observe marine life, bring light into the ocean, and observe the ocean.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the manufacturing process of a floating concrete structure according to the present invention.

FIG. 2 is a perspective view showing the manufacturing process of a floating concrete structure according to the present invention.

FIG. 3 is a perspective view of a completed floating concrete structure according to the present invention.

FIG. 4 is a cross-sectional view of a floating concrete structure equipped with a viewing window.

[Explanation of symbols]

1　　　　　bed 2 Steel plate bed 3 Inner formwork 4 Main story 5 Stirrups 6 PC steel wire 7 Outer formwork 8 Main body 9 Gable outside formwork 9′ Gable side formwork １０　　　Protrusion axis 11 Small beam 12 Inner formwork floating prevention device 13　　　类子 14 Rubber sheet 15 Tempered glass block 16 Window 17 Pipe members 18 Peephole D Centroid G Center of gravity

Claims (2)

[Claims] Claim 1: A substantially box-shaped foamed member is used as an inner form, and an outer form that is one step taller than the top of the inner form is erected around the inner form; Build a prestressed concrete structure using the pretension method using the frame and outer formwork.
A method for manufacturing a floating concrete structure having a substantially U-shaped cross section, characterized by lifting the floating concrete structure and turning it upside down using protruding shafts protruding from both end faces. [Claim 2] A floating concrete structure characterized by being provided with a viewing window for looking into the water.