JP3181786B2 - Filling method of high fluidity concrete into steel shell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling concrete with high fluidity in a steel shell for filling concrete with high fluidity in a steel shell so as not to form voids. It is used for submerged boxes of composite structures (steel-concrete sandwich structures), and mainly for construction of large-scale steel-concrete composite structures.

[0002]

2. Description of the Related Art As a submerged box used in the construction of a submerged tunnel, one having a reinforced concrete or steel-concrete composite structure is generally used. In particular, when high rigidity and high watertightness are required, a steel-concrete composite structure is desirable, and a so-called steel-concrete sandwich structure in which a steel shell is filled with concrete tends to be used. FIG. 4 shows an example of a cross section in a direction perpendicular to the tunnel axis of a submerged box 20 of a steel-concrete composite structure to which the present invention is applied (right and left sides). In this example, the upper floor slab 21 of the submerged box 20 is used.
The side wall 23 has a so-called full sandwich structure in which a double steel shell is filled with concrete, the lower slab 22 has a so-called open sandwich structure having a steel plate only on the lower surface, and the partition 24 has a reinforced concrete structure. The lower slab 22 also has a full sandwich structure in which double steel shells are filled with concrete similarly to the upper slab 21.

FIG. 5 schematically shows the structure of the portion A at the position of the upper slab 21 in FIG. 4. The upper and lower steel plates 2 and 3 (skin plates) and the shear reinforcement in the axial direction of the tunnel as the side steel plate 4 are shown. Steel plate 4a and shear-reinforced steel plate 4 perpendicular to the tunnel axis
b constitutes a steel shell 1 whose six surfaces are closed (in the figure, one unit of the steel shell is indicated by hatching). On the upper surface of the lower steel plate 3 of the steel shell 1, a shear connector 5 formed of an angle in the axial direction of the tunnel and a stiffener 6 formed of a flat bar shorter than the shear connector 5 protrude. An axial shear connector 5 protrudes, and a stiffener 6 made of a flat bar (or a lower surface) protrudes from the upper surface. The shear connector 5 is mainly intended for integration with the concrete 11 filled in the steel shell 1 (also has a function as a stiffener). The purpose is to prevent bending of the steel plate 2 and the lower steel plate 3 (the one protruding into the steel shell 1 also functions as a shear connector to some extent).

[0004] Regarding the production of such a submerged box 20,
For example, a steel shell 1 manufactured at a factory is assembled by welding with a dock, and then the concrete 1 is placed in the steel shell 1 and the formwork.
An operation such as filling 1 is performed. At this time, the filling of the concrete 11 into the double steel shell 1 constituting the closed space as shown in FIG. 5 becomes a problem. When ordinary concrete is used for filling in the steel shell 1, in order to prevent insufficient filling, that is, to prevent voids from being generated in the steel shell 1, a large number of concrete The inlet must be cut out, and concrete must be poured from each inlet while moving the tip of the concrete pipe connected to the pump or the tremee pipe. Further, in the case of ordinary concrete, compaction by a vibrator is essential, but it is still difficult to fill the upper part of the steel shell 1 so that no void is formed, and the presence of ribs such as the shear connector 5 and the stiffener 6 , Making filling even more difficult. For this reason, when ordinary concrete is used, it is necessary to fill the void portion with an epoxy resin or the like later. On the other hand, it is conceivable to fill the steel shell 1 with highly fluid concrete that does not require compaction. For concrete with high fluidity, adjust the amount of cement and fly ash, particle size, etc., or use blast furnace slag fine powder or ultra fine powder,
Furthermore, by adding a high-performance water reducing agent, other surfactants and thickeners as necessary as an admixture, the fluidity in the uncured state is greatly improved, and it is difficult for aggregate separation to occur. Concrete capable of obtaining a high-quality hardened concrete body by reducing the ratio or the like has been developed (for example, JP-A-3-237049, JP-A-4-4-1).
No. 64849). These are called hyper-performance concrete, super-fluid concrete, compaction-free concrete, high-fluid concrete, and the like. In the present application, these are referred to as high-fluid concrete.

[0005]

Even when the above-mentioned high-fluidity concrete is used, unfilled portions, ie, voids, which are unacceptable as a steel-concrete composite structure may remain in the upper portion of the steel shell 1. is there. As one of the causes, a shear connector 5 protruding from the lower surface of the upper steel plate 2 and a rib as a stiffener 6 (a steel bar such as an angle other than a flat bar is often used) often hinders the flow. It is considered that the concrete 11 flows in the direction with less resistance, and the wraparound from below at the rib position or the like becomes insufficient. Also, as another cause, related to the air bleeding during concrete filling, if the resistance at the air bleeding position is small,
It is conceivable that the concrete tends to flow toward the air bleeding position where the resistance pressure is small, and the flow in other directions becomes insufficient. For example, as a conventional general filling method and air bleeding method, as shown in FIG. 3, a driving hole 7 is provided at the center of the upper steel plate 2, and a plurality of discharge ports 9 are provided near the outer peripheral portion. A hose 13 is connected to the outlet 9 to overflow the filled concrete 11. However, since there is no resistance pressure at the discharge port 9, the filled concrete 11 easily flows out of the specific discharge port 9, and the concrete 11 flows in the other direction. There are cases where the elimination of voids in the shell 1 is insufficient. The present invention has been made to solve the above-described problems, and by improving the filling position and the air bleeding method, the concrete filling property is improved, and a high-quality steel-concrete composite structure having no voids is efficiently manufactured. It is an object of the present invention to provide a method for filling a highly fluid concrete into a steel shell which can be obtained well and economically.

[0006]

The invention corresponding to claim 1 of the present invention is characterized in that a casting port 7 and a discharge port 9 for bleeding air are provided on an upper steel plate 2 constituting a steel shell 1, and the casting port 7 is provided. In the method of filling the high fluidity concrete 11 having a more predetermined fluidity into the steel shell 1, the upper steel plate 2 is provided with a stiffener 6 in a specific direction protruding from the lower surface of the upper steel plate or a rib as the shear connector 5. Considering a plurality of sections to be partitioned, a casting port 7 is provided at an end of at least two or more sections of the plurality of sections, and concrete is filled from these casting ports 7. The division into a plurality of sections takes into account that the wraparound of the concrete at the rib position is hindered, and it is certain that all the sections are provided with a casting hole. Depending on the fluidity (usually measured by a slump flow value), sufficient filling property can be ensured by providing, for example, every other one, even if not provided in every section. Also, the reason why the casting port 7 is provided at the end rather than the center of the section is that when the filling is performed from the center, the flow distance is the shortest, but the flow of concrete during casting is not uniform in all directions. The reason for this is that the concrete may flow toward the side with the smaller resistance and return to produce an unfilled portion. The filling of the high-fluidity concrete 11 from the plurality of casting ports 7 can be performed by separate concrete transport pipes 12, respectively. However, by using the concrete transport pipe 12 having the branch pipe 12a, one concrete transport pipe 12 is used. Concrete can be filled at the same time using a pump truck. In addition, when the highly fluid concrete 11 is filled into the steel shell 1, air bleeding is required. However, a plurality of discharge ports 9 for bleeding air are provided, and pipes of a required height are erected at each discharge port. If the concrete overflowing from the inside of the steel shell 1 is pushed into the pipe at the discharge port, a resistance pressure corresponding to the height of the concrete in the pipe is applied from the discharge port into the steel shell, and the concrete flows excessively. Or the flow of concrete in the steel shell 1 can be prevented from being biased. As described above, the most reasonable position of the discharge port 9 in the case where the casting port 7 is provided at the end of the section is considered to be provided at the end opposite to the casting port 7. There is no need to limit. In addition, by disposing a plurality of discharge ports 9 in a dispersed manner, it is possible to prevent uneven flow of concrete in the steel shell 1. The invention corresponding to claim 5 of the present invention is:
In addition to the problem of the concrete wrap around at the rib position, the concrete flow in the steel shell 1 is more taken into consideration, and the casting port 7 is located at the center of a plurality of sections partitioned by the rib. Provided at the end of the section where it is located, and provided with a plurality of discharge ports 9, pipes of the required height are erected at each of the discharge ports, and while giving resistance pressure against concrete filling by concrete overflowing from inside the steel shell 1,
It is characterized in that concrete is filled from the casting opening 7. In this case, only one casting port 7 may be used, and concrete is sequentially filled from one side of the steel shell 1 and a plurality of discharge ports 9 apply a resistance pressure corresponding to the height of the concrete extruded into the pipe. In addition, it is possible to prevent the flow of the concrete in the steel shell 1 from being biased, thereby enabling uniform filling in which voids are hardly generated. The high-fluidity concrete 11 used in the present invention is assumed to have a slump flow value of about 50 to 80 cm, preferably about 60 to 75 cm.

[0007]

In the invention corresponding to claim 1 of the present invention,
Since the high-fluidity concrete 11 filled from the casting port 7 at one end of the plurality of sections gradually flows in the steel shell 1 along the rib in a specific direction to the other side, the existence of the rib is not so large. This prevents the filled concrete from being insufficiently filled at the rib position without obstructing the flow. in this case,
Even if it is not necessarily provided in each section, since the flow direction coincides with the rib direction, there is less obstruction of the flow as compared with the case where the installation port 7 is provided in the center. If the rib direction of the lower surface of the upper steel plate 2 of the steel shell 1 is one direction, there is no problem at all, but in the case of two directions, the direction of the rib which is likely to hinder the flow may be selected in a specific direction. If so, either one may be selected. The invention corresponding to claim 2 of the present invention aims at uniform filling by using the branch pipe 12a, and the sections of the steel shell 1 are only partitioned by ribs.
Actually, since the concrete filling space is continuous, the filling is performed simultaneously by using the branch pipe 12a or the like, so that the steel shell 1 can be uniformly filled from one side to the other side. In the invention corresponding to claims 3 and 5 of the present invention, a plurality of discharge ports for venting air are provided, and a pipe having a required height is erected at each discharge port 9 so that concrete overflowing from inside the steel shell 1 is formed. By being pushed out into the pipe at the discharge port, the resistance pressure P corresponding to the height of the concrete inside the pipe 10 at the discharge port 9 also corresponds to the head pressure P ₀ at the casting port 7 as shown in FIG. _{Since 1} and P ₂ are supplied from the discharge port 9 into the steel shell 1, it is possible to prevent the concrete 11 from being excessively washed out and the flow of the concrete 11 in the steel shell 1 from being biased. For example, in the method of simply connecting the hose 13 to the discharge port 9 to overflow the concrete 11 as shown in FIG. 6 (see FIG. 3), the concrete 11 easily flows in the direction of low resistance, and the concrete in the steel shell 1 The flow of 11 is not uniform, which causes a void. The invention corresponding to claim 4 of the present invention provides an arrangement of discharge ports which is considered to be the most efficient in performing uniform filling with directionality in the inventions of claims 1 to 3. .

[0008]

FIG. 1 schematically shows an embodiment of the invention corresponding to claims 1 to 4 of the present invention. The steel shell 1 corresponds to one unit of the steel shell 1 in which six surfaces are closed in the above-described submerged box 20 of FIGS. 4 and 5.
The width in the direction perpendicular to the tunnel axis and the depth in the tunnel axis direction are about 3 m, and the height is about 1.1 m. Further, in this figure, only the shear connector 5 formed by an angle in the tunnel axis direction is shown by a broken line, and the stiffener 6 formed by a flat bar in the direction perpendicular to the tunnel axis is omitted. Upper steel plate 2 constituting steel shell 1
On the lower surface of the steel plate 2, three shear connectors 5 in the direction of the tunnel axis protrude in parallel, and it is assumed that a stiffener in the direction perpendicular to the tunnel axis (not shown) protrudes from the upper surface of the upper steel plate 2.
In addition, even when the stiffener protrudes from the lower surface of the upper steel plate 2, if the stiffener is shorter than the shear connector 5, the stiffener does not obstruct the flow much. Further, in the present embodiment, for each of the four sections partitioned by the shear connector 5 in the tunnel axis direction, a driving port 7 is provided at one end and a discharge port 9 is provided at the other end. .

[0009] Pipes 8 of a required height are erected at the casting port 7, and the tip of a branch pipe 12 a connected to the concrete transport pipe 12 is inserted into each pipe 8, and the highly fluid concrete is inserted into the steel shell 1. Fill 11 At this time, the pipe tip is pipe 8
A head pressure corresponding to the concrete height in the pipe 8 acts on the concrete 11 located in the concrete 11 and filled in the steel shell 1. Although the figure assumes a four-branch branch pipe 12a, four-branch pipes can also be made into four branches by combining three commercially available two-branch pipes. By simultaneously filling the high fluidity concrete 11 from the four casting ports 7 in this manner, the filled concrete 11 flows in the direction of the shear connector 5 from the casting port 7 side to the discharge port 9 side. While filling the inside of the steel shell 1. Also, a pipe 10 having a predetermined height is provided upright at the discharge port 9 so that the concrete 11 overflowing from the inside of the steel shell 1 is pushed into the pipe 10 of the discharge port 9, so that the steel shell is discharged from the discharge port 9. 1 is provided with a resistance pressure corresponding to the height of the concrete in the pipe 10 and a specific discharge port 9 is provided.
From being excessively washed away from the concrete, and uneven flow of the concrete in the steel shell 1 is prevented.

As an example of the composition of the high-fluidity concrete used in the present embodiment, for example, the composition shown in Table 1 is possible.

[Table 1] In Table 1, OPC is ordinary Portland cement (specific gravity 3.15, Blaine specific surface area 3270 cm ² / g
), BFS is blast furnace slag fine powder (specific gravity 2.89, Blaine specific surface area 5920 cm ² / g), S is fine aggregate, G is coarse aggregate, and SP is a high-performance AE water reducing agent (naphthalene sulfonic acid type). .

FIG. 2 schematically shows an embodiment of the present invention corresponding to claim 5 of the present invention. The configuration of the steel shell 1 is the same as that of FIG. In this embodiment,
Of the four sections partitioned by the shear connector 5 in the axial direction of the tunnel, a driving port 7 is provided at one end of a section on one side of the center, and discharge ports 9 are provided on both sides at the other end. Casting mouth 7
The structure of the discharge port 9 is the same as that of FIG. The highly fluid concrete 11 filled from the pouring opening 7 fills the inside of the steel shell 1 while flowing obliquely to the direction of the shear connector 5. In addition, it is also conceivable that the discharge ports 9 are provided, for example, at both ends or one end on the placement port 7 side in addition to the two places shown in the figure. In addition, the filling port 7 is also provided, for example, in the other section in the center, and the filling property is further improved by simultaneously filling the concrete from the two setting ports.

FIGS. 8 and 9 show an example of the structure of the discharge port 9 used in the present invention.
On the other hand, as shown in FIG. 8, the pipe 10 can be fixed with bolts or clips 14, so that after the highly fluid concrete 11 is filled into the steel shell 1, the pipe 10 remains unhardened.
Can be easily removed. Further, in this case, as shown in FIG. 9, a concrete plate 15 made of a thin plate having a slit or a wire mesh can be inserted horizontally, and when the pipe 10 is detached, the concrete plate 15 exerts a closing effect so that concrete can be removed. It is also possible to prevent 11 from spilling.

[0013]

According to the present invention, when the high-fluidity concrete 11 is filled in the steel shell 1, the high-fluidity concrete 11 filled from the casting port 7 at one side end of the plurality of sections is filled with the steel shell 1. The inside flows in a specific direction, the existence of ribs and the like hardly hinders the formation of voids in the steel shell, and a high-quality steel-concrete composite structure can be obtained. In addition, since the filling of the high fluidity concrete 11 is ensured, the workability can be improved and the construction period can be shortened, and the total cost can be reduced even if the material cost increase of the high fluidity concrete 11 with respect to the ordinary concrete is considered. It becomes possible. further,
In the invention corresponding to claim 3 or 5 of the present application, since the resisting pressure can be applied to the concrete in the steel shell 1 at the discharge port, the loss of concrete due to overflow can be suppressed, and the steel in the steel shell 1 can be suppressed. The effect of equalizing the flow of the concrete ensures more reliable filling.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an embodiment of the invention corresponding to claims 1 to 4 of the present invention.

FIG. 2 is a perspective view schematically showing one embodiment of the invention corresponding to claim 5 of the present invention.

FIG. 3 is a perspective view schematically showing an example of a conventional filling method.

FIG. 4 is a sectional view of a right half in a direction perpendicular to a tunnel axis, showing an example of a submerged box of a steel-concrete composite structure to which the present invention is applied.

FIG. 5 is a perspective view schematically showing a structure of a part A in FIG. 4 with a part cut away.

FIG. 6 is an explanatory diagram of a problem in a conventional filling method.

FIG. 7 is an explanatory diagram of an operation of a discharge port in the present invention.

FIG. 8 is a vertical sectional view showing an example of the structure of a discharge port used in the present invention.

FIG. 9 is a horizontal sectional view of a concrete stopper portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel shell 2 Upper steel plate 3 Lower steel plate 4 Side steel plate 4a Tunnel axis direction shear reinforcement steel plate 4b Tunnel axis perpendicular direction shear reinforcement steel plate 5 Shear connector 6 Stiffener 7 Casting hole 8 Pipe 9 Discharge port 10 Pipe 11 High fluidity concrete DESCRIPTION OF SYMBOLS 12 Concrete transport piping 12a Branch pipe 13 Hose 14 Bolt or clip 15 Concrete stopper 20 Sunk box 21 Upper floor slab 22 Lower floor slab 23 Side wall part 24 Partition part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E04G 21/02 103

Claims (5)

(57) [Claims] 1. A method for filling a concrete 11 having a predetermined fluidity from the casting port 7 by providing a casting port 7 and a discharge port 9 for bleeding air in the upper steel plate 2 constituting the steel shell 1. Considering a plurality of sections of the upper steel plate 2 which are partitioned by a stiffener in a specific direction protruding from the lower surface of the upper steel plate 2 or a rib serving as a shear connector 5, the driving hole 7 is formed by at least two or more of the plurality of partitions. At the end of the compartment
A method for filling high-fluidity concrete into steel shells, wherein concrete is filled from a plurality of the casting holes 7. 2. The method for filling high-fluidity concrete into a steel shell according to claim 1, wherein the concrete is simultaneously filled from the plurality of casting holes by a concrete transportation pipe having a branch pipe. 3. The discharge port 9 according to claim 1, wherein a plurality of discharge ports 9 are provided, and a pipe 10 having a required height is erected at each of the discharge ports 9 to provide a resistance pressure against filling by concrete overflowing from inside the steel shell. Filling method for highly fluid concrete. 4. The method of filling high-fluidity concrete according to claim 3, wherein the discharge port is provided at an end of the section where the placement port is provided, on the opposite side to the placement port. 5. A method for providing a casting port 7 and a discharge port 9 for bleeding air in the upper steel plate 2 constituting the steel shell 1 and filling concrete having a predetermined fluidity from the casting port 9
Considering a plurality of sections of the upper steel plate 2 which are partitioned by a stiffener 6 or a rib as a shear connector 5 in a specific direction protruding from the lower surface of the upper steel plate 2, the driving hole 6 is positioned at the center of the plurality of partitions. Provided at the end of the section located in the part,
Also, a plurality of the discharge ports 9 are provided, and pipes of a required height are erected at each of the discharge ports 9 to give a resistance pressure to the concrete filling by the concrete overflowing from the inside of the steel shell. A method for filling high-fluidity concrete into a steel shell, comprising performing filling.