KR100803558B1 - A reinforcing single column drilled pier foundation and construction method thereof - Google Patents

Abstract

A reinforcing type single cast-in-place pile foundation is provided to increase constructability and economical efficiency by heightening stiffness and ductility of a part where a steel pipe is installed and increasing resistance to bending moment, and reducing the cross sectional area of a pile foundation and the quantity of reinforcing bars required by installing a steel pipe to the top of a pile applied with maximum load when constructing a pile foundation. A reinforcing type single cast-in-place pile foundation(100) for heightening stiffness and ductility of the top of a pile applied with maximum load when constructing a pile foundation and increasing resistance to bending moment comprises a reinforcement cage composed of many main reinforcements(141) and hoop reinforcements(142) and inserted to the inside of the pile foundation, a cylindrical steel pipe(120) inserted to the center of the reinforcement cage, and a steel pipe mounting plate(130) installed to the reinforcement cage to mount the steel pipe and provided with many tremie pipe insertion holes to insert tremie pipes for placing concrete in an inside space of the steel pipe. A construction method of a reinforcing type single cast-in-place pile foundation comprises the steps of: excavating the bottom of a construction site where a pile foundation is to be constructed to the planned depth using excavation equipment; installing a reinforcement cage coupled with a steel pipe mounting plate in the excavated space, inserting a steel pipe into the reinforcement cage to be put at the center of the steel pipe mounting plate; and inserting tremie pipes to tremie pipe insertion holes formed on the steel pipe mounting plate, injecting concrete to the inside of the tremie pipes and placing concrete in a circumferential space of the steel pipe, and then curing the concrete surface.

Description

Reinforcing single column drilled pier foundation and construction method

1 is a conceptual diagram showing a reinforced single cast site pile foundation according to an embodiment of the present invention.

Figure 2 is a detailed view showing the structure of the reinforced cage of the present invention in detail.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a graph schematically showing the acting moment and the resistance moment acting on the reinforced single cast-in-place pile foundation according to the present invention.

5 is a cross-sectional view showing a cross-sectional structure of the pile foundation to which the corrugated steel pipe is applied as another embodiment of the present invention.

6 is a perspective view showing a corrugated steel sheet structure for manufacturing the corrugated steel pipe of FIG.

7 is a detailed view showing a modified embodiment of the steel pipe according to the present invention.

8 is a detailed view showing another modified embodiment of the steel pipe according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100: pile foundation 102: pile

104: pier 120: steel pipe

130: steel pipe mounting plate 132: tremi tube insertion hole

134: fixed rib 140: reinforced cage

141: cast iron 142: strip reinforcement

The present invention relates to a single cast-in-place pile foundation and its construction method that are constructed in a single-piece structure in which the bridge and pile foundations forming a substructure of the bridge are continuous, and more specifically, the maximum load during construction of the pile foundation. By increasing the resistance to the bending moment of the upper pile part to be received, it is possible to reduce the cross-sectional area of the pile foundation and to reduce the amount of reinforcing bars, and to make excavation work by putting a small excavation equipment during construction, thereby greatly improving workability and economic efficiency. Reinforced single cast-in-place pile foundation and its construction method.

In general, the cast-in-place concrete pile method is a method of constructing piles in the field by inserting reinforcing cages made of reinforcing bars and drilling concrete using a tremi tube after digging to the depth of the ground using excavation equipment. After piles were piled, pile piles were installed on top of piles to receive loads from the top.However, a more improved construction method is to form pile foundations with a diameter equal to or slightly larger than the diameter of piers. By connecting the foundation directly with the piers, there was a method to construct the piers and pile foundations into a continuous unitary structure.

Since the foundation of the cast-in-place pile is excavated continuously through the excavation equipment, it is possible to excavate to a deep depth, and the deeper the depth is, the more efficient than the other methods, and the application can be applied regardless of layers. By bit, the soft rock layer was also widely used because it has the advantage of being excavated with no vibration.

However, in the case of the conventional cast-in-place pile foundation as described above, in the case of the cast-in-place pile foundation, it is inevitable to use high-strength concrete or increase the amount of reinforcement to resist the bending moment acting at the upper end of the pile foundation. There was a problem in that the economic feasibility and constructionability were deteriorated because it had to increase the cross-sectional area of the pile foundation or increase the number of pile foundations.

In addition, in the case of a single cast-in-place pile foundation consisting of a monolithic piling and a pile foundation, the diameter of the piers is affected by the diameter of the piers. In this case, the diameter of the cast-in-place pile foundation had to increase, and the size of the pile foundation was determined according to the diameter of the lower part of the piers due to the characteristics of the single-cast pile foundation. There was a problem that has been applied to.

In addition, as the diameter of the pile foundation increases, the size of the mechanical equipment for excavating the ground not only increases exponentially, but also increases the power required to operate the equipment. It was not applicable in the section, and most of them were applied only to the marine section with less restrictions on transportation or working space.

In addition, even if the diameter of the cast-in-place pile foundation is limited by space constraints, such as downtown construction, there is a problem such that the application is limited.

Accordingly, the present invention has been made to solve the problems as described above, the object of the present invention is the role of reinforcement for compression and shear in the pile upper end portion that is subjected to the maximum load during the construction of the pile foundation in a single cast-in-place pile foundation By inserting the steel pipe to insert the steel pipe, the rigidity and ductility of the steel pipe can be increased to increase the resistance to the bending moment, thereby reducing the rebar amount along with the reduction of the cross-sectional area of the pile foundation, which greatly improves the constructability and economic efficiency. It is to provide a reinforced single cast-in-place foundation and construction method thereof.

Reinforcing single cast-in-place pile foundation according to the present invention for achieving the above object, in the single cast-in-place pile foundation is constructed in the form of a single-piece structure is continuous bridge and pile foundation to form a substructure of the bridge, A reinforcing cage inserted into and installed in the pile foundation; Steel pipe is inserted into the center of the reinforcing cage; And a steel pipe mounting plate installed in the reinforcing cage so that the steel pipe is mounted, wherein the steel pipe is installed to be disposed over the upper end of the pile located at the bottom of the ground and the lower end of the piers located at the top of the ground. do.

A fixing rib for fixing the lower end of the steel pipe may be formed in the center of the steel pipe mounting plate.

In addition, the steel pipe mounting plate may be formed with a tremi tube insertion hole into which the tremi tube can be inserted.

In this case, the tremi tube insertion hole may be formed to be disposed inside the steel pipe.

Meanwhile, the steel pipe may be adopted as a corrugated steel pipe whose outer peripheral surface is curved in a wavy shape.

In addition, concrete may be poured into the corrugated steel pipe.

In addition, on the outer circumferential surface of the steel pipe of the present invention, a plurality of protrusions in the form of hollow tubes or hollow rods can be radially attached.

Alternatively, a plurality of reinforcing bars parallel to the steel pipe may be attached to the inner circumferential surface of the steel pipe at equal intervals, and both ends of the reinforcing bars may protrude from both ends of the steel pipe by the length of reinforcing bars.

On the other hand, reinforcement type single-site casting pile foundation construction method according to the present invention for achieving the above object, the step of excavating the site floor to install the pile foundation using the excavation equipment; Inserting a reinforcing cage in which a steel pipe mounting plate is coupled to the excavated space; Inserting the steel pipe into the reinforcing cage and placing the steel pipe in the center of the steel pipe mounting plate so that the steel pipe is disposed over the upper end of the pile and the lower end of the piers; It characterized in that it comprises a step of curing by pouring concrete in the outer space of the steel pipe.

In this case, the steel pipe may be employed as a corrugated steel pipe whose outer circumferential surface is curved in a wavy shape, and concrete may be poured into the corrugated steel pipe.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a reinforced single cast site pile foundation according to an embodiment of the present invention. In addition, Figure 2 is a detailed view showing in detail the structure of the reinforcing cage having a steel pipe mounting plate on which the steel pipe of the present invention, Figure 3 is a cross-sectional view of the section AA of Figure 1, Figure 4 This is a graph showing the moment of action and the moment of resistance acting on the foundation of a reinforced single cast site pile.

Reinforcement single cast-in-place pile foundation according to the present invention is a single cast-in-place pile foundation in which the piers and piles that form the substructure of the bridge to be continuously cast into a single body structure, to receive the maximum load during construction of the pile foundation By increasing the stiffness and ductility of the top of the pile to increase the resistance to the bending moment, it is possible to reduce the cross-sectional area of the pile foundation to greatly improve the construction and economic efficiency of the pile foundation.

To this end, the reinforced single cast-in-place foundation 100 of the present invention is a cylindrical steel pipe having a predetermined thickness as a reinforcement for compression and shear in the inner center of the pile foundation 100 as shown in the accompanying drawings of FIGS. 120 is installed, the upper end and the ground surface (E) of the pile 102 located in the lower portion of the ground surface (E) in consideration of the fact that the normal maximum load is concentrated on the upper end of the pile 102 during the installation of the steel pipe (120) The steel pipe 120 is positioned over the lower end of the pier 104 located above.

At this time, the steel pipe 120 is preferably constructed by properly selecting the diameter and thickness in consideration of the size of the maximum load acting on the upper portion of the pile (102).

On the other hand, in the installation of the steel pipe 120 is inserted into the reinforcing cage 140 consisting of a plurality of cast iron 141 and the band reinforcing bars 142 in the space excavated to a predetermined depth for the construction of the pile foundation Construction is carried out in a state where the steel pipe 120 is mounted at a predetermined position of the reinforced cage 140.

The structure of the reinforcing cage 140 on which the steel pipe 120 is mounted is shown in detail in FIG. 2. As shown in FIG. 2, the steel pipe 120 may be mounted at a predetermined position in the longitudinal direction of the reinforcing cage 140. The steel plate mounting plate 130 is coupled to.

At this time, the plurality of cast steel 141 of the reinforcing cage 140 forms a structure coupled to penetrate vertically through the inner edge of the steel pipe mounting plate 130, the center of the upper surface of the steel pipe mounting plate 130 The fixed rib 134 that can be inserted is inserted into the lower end of the steel pipe 120 is mounted is formed protruding in an annular shape. Therefore, the steel pipe 120 mounted on the steel pipe mounting plate 130 is constrained by the fixing ribs 134 so that the steel pipe 120 may be installed at an accurate position in the center of the reinforcing cage 140 without flowing from side to side.

In addition, the steel pipe mounting plate 130, a plurality of tremi tube insertion holes that can be inserted into the tremi tube is injected concrete so that the concrete can be poured in the state in which the reinforced cage 140 is inserted into the excavated space 132 is formed.

In this case, it is preferable that the tremi tube insertion hole 132 is formed to be arranged in a circular shape on the outside spaced apart from the fixed rib 134 by a predetermined distance.

The tremi tube insertion hole 132 can be formed in the inner side of the steel pipe 120 as well as the outside of the steel pipe 120 as described above. That is, a tremi tube insertion hole (not shown) is formed in the center of the inner steel pipe mounting plate 130 of the fixed rib 134, and the concrete is inserted into the inner space of the steel pipe 120 by inserting a tremi tube into the tremi tube insertion hole. Can be configured to be poured.

Reinforced single site placing pile foundation construction method of the present invention having the above-described configuration, first excavating the floor surface of the site to install the pile foundation 100 using the excavation equipment to the planned depth.

In addition, after the steel cage 140 is installed by sinking the steel pipe mounting plate 130 coupled to the inside of the excavated space, the steel pipe 120 is inserted into the interior of the steel cage 140 for the steel pipe mounting It is installed to be mounted in the center of the plate 130.

In this process, the lower end of the steel pipe 120 is fitted to the fixed rib 134 of the annular (상) formed on the upper surface of the steel pipe mounting plate 130 is fixed so as not to flow and at the same time the upper end of the steel pipe 120 (E) By being supported through a separate support from above, the steel pipe 120 can be installed on the correct center position without being sloped to one side inside the reinforced cage 140.

The steel pipe 120 constructed inside the reinforced cage 140 as described above is disposed over the upper end of the pile 102 located at the lower portion of the ground surface E and the lower end of the pier 104 located at the upper surface E. .

After the installation of the steel pipe 120 is completed, the tremi tube (not shown) for placing the concrete is inserted into the tremi tube insertion hole 132 formed in the steel pipe mounting plate 130 and then the concrete (150) ) By pouring concrete 150 into the surrounding space of the steel pipe 120 and curing to complete the construction of the pile foundation (100).

The moment acting on the reinforced single cast-in-place foundation of the present invention constructed through the above process can be seen in the graph of FIG. Here, Figure 4 (a) shows the acting moment acting along the longitudinal direction of the general pile foundation 100, (b) is the resistance moment when the reinforcing steel pipe 120 of the present invention is installed It is showing.

Reinforcing single cast-in-place pile foundation of the present invention having the above-described configuration by inserting the steel pipe 120, which serves as a reinforcement for compression and shear in the upper end portion of the pile that is subjected to the maximum load during construction of the pile foundation ( 120) can increase the resistance to the bending moment by increasing the rigidity and ductility of the installed part, it is possible to reduce the cross-sectional area of the pile foundation compared to the conventional cast-in-place pile foundation, which is a small excavation equipment when the pile foundation Since excavation is possible by using, construction and economics can be greatly improved. In addition, the amount of reinforcing steel used in the construction of the pile foundation 100 may be greatly reduced, and the amount and weight of concrete placed in the pile foundation 100 may be reduced, as well as rigidity due to the mutual complementary action of the steel and concrete. It is excellent in ductility and can improve seismic performance.

On the other hand, Figure 5 shows another embodiment of the present invention, it shows a cross-sectional shape in which the corrugated steel pipe 122 is inserted into the pile foundation (100).

As shown in FIG. 5, in addition to the circular steel pipe 120 described above, a corrugated steel pipe 122 having a corrugated curved shape may be inserted in addition to the circular steel pipe 120 described above. .

The corrugated steel pipe 122 is formed by forming a tube by welding or bolting the corrugated steel sheet curved in a wavy shape as shown in FIG. 6 at a construction site, and to be constructed as shown in Table 1 below. Depending on the cross-sectional area of the pile foundation, one of the standard type and the skeleton type within the range of 1.6 to 7.0 mm can be selected and used.

In this case, since the corrugated steel pipe 122 may be weaker in strength than the above-described circular steel pipe, it is preferable to construct the corrugated steel pipe 122 in order to improve the load capacity, and then cast concrete 152 therein.

On the other hand, Figures 7 and 8 shows a form of another embodiment of the modified steel pipe 120 in the single cast-in-place pile foundation according to the present invention.

That is, the steel pipe 120 is inserted into the pile foundation of the present invention is a rectangular square tube 122 or a hollow rod (의) of the hollow tube (pipe) shape on the outer circumferential surface of the steel pipe 120 as shown in Figure 7 By attaching a plurality of rectangular square rods (122) shape to be arranged in a radial manner, it is possible to employ a structure that can increase the adhesion between the concrete and the steel pipe 120 placed outside the steel pipe (120). Can be.

In addition, the steel pipe 120 of the present invention is attached to a plurality of reinforcing bars 124 parallel to the steel pipe 120 on the inner circumferential surface of the steel pipe 120, as shown in Figure 8, the reinforcing bars 124 are mutually It can be arranged and fixed so as to maintain equal spacing.

At this time, the upper and lower ends of the reinforcing bars 124 are formed so as to protrude from the upper and lower ends of the steel pipe 120 by the reinforcing bar length (L), when the concrete is poured into the steel pipe 120, the concrete and steel pipe 120 It is possible to increase the adhesion strength between, it is possible to prevent the occurrence of stress concentration due to the rapid cross-sectional change of the pile foundation due to the steel pipe 120 installation.

According to the reinforced single cast-in-place pile foundation of the present invention having the above configuration, the steel pipe is installed by inserting the steel pipe acting as a reinforcement for compression and shear in the upper end portion of the pile that is subjected to the maximum load during construction of the pile foundation Since the resistance to bending moment can be increased by increasing the rigidity and ductility of the pile foundation, it is possible to reduce the cross-sectional area of the pile foundation compared to the conventional cast-in-place pile foundation, which makes excavation by using a small excavation equipment when constructing the pile foundation. It is possible to greatly improve workability and economics.

In addition, since the steel pipe is inserted up to the maximum load acting on the lower end of the pier and the pile foundation, the amount of rebar used in the construction of the pile foundation can be greatly reduced, and the reinforcing steel can be easily assembled to improve the economics and the constructability.

In addition, it is possible to reduce the amount of concrete pouring and the weight of the pile foundation, as well as the stiffness as well as ductility by the complementary action of the steel and concrete has an excellent effect to improve the seismic performance.

In addition, there is an effect that can easily improve the load capacity of the bridge by filling the concrete inside the steel pipe constructed as needed.

In addition, when a corrugated steel pipe is applied to the pile foundation of the present invention, the corrugated steel sheet curved in a wavy shape can be easily rolled and welded or bolted directly at a construction site, thereby improving workability.

In addition, by attaching a plurality of hollow rectangular square tube or hollow rod rectangular square bar on the outer circumferential surface of the steel pipe to form a radial arrangement, it is possible to increase the adhesion between the concrete and the steel pipe placed outside the steel pipe There is.

In addition, a plurality of rebars parallel to the steel pipe is attached to the inner circumferential surface of the steel pipe to form an equal interval, but both ends of the reinforcement is formed so as to protrude by the reinforcing rod length from both ends of the steel pipe, when the concrete is poured into the steel pipe It is possible to increase the adhesion strength between the steel pipe, and there is an effect that can prevent the stress concentration due to the rapid cross-sectional change of the pile foundation due to the steel pipe installation.

Claims (10)

In the single cast-in-place pile foundation, in which the piers and pile foundations forming the substructure of the bridge are cast in the form of a continuous monolithic structure, A reinforcing cage inserted into and installed in the pile foundation; Steel pipe is inserted into the center of the reinforcing cage; And Is configured to include a steel pipe mounting plate which is installed in the reinforcing cage so that the steel pipe is mounted, Reinforced single cast-in-place foundation, characterized in that the steel pipe is installed so as to be disposed over the upper end of the pile located in the lower portion of the ground surface and the lower end of the piers located in the upper surface portion. According to claim 1, Reinforced single cast-in-place foundation, characterized in that the fixing ribs for fixing the lower end of the steel pipe mounting plate is formed in the center of the steel pipe mounting plate. According to claim 1 or 2, Reinforced single cast-in-place foundation, characterized in that the steel pipe mounting plate is formed with a tremi tube insertion hole into which the tremi tube can be inserted. 4. The reinforced single cast-in-place foundation of claim 3, wherein the tremi tube insertion hole is formed to be disposed inside the steel pipe. The reinforced single cast site foundation of claim 1, wherein the steel pipe is a corrugated steel pipe whose outer circumferential surface is curved in a wavy manner. 6. The reinforced single site casting pile foundation according to claim 5, wherein concrete is poured into the corrugated steel pipe. According to claim 1, wherein the outer circumferential surface of the steel pipe reinforcement single cast-in-place foundation, characterized in that a plurality of protrusions in the form of a hollow tube (cold) or a hollow rod (60) is radially attached. The reinforcement of claim 1, wherein a plurality of rebars parallel to the steel pipe are attached to the inner circumferential surface of the steel pipe at equal intervals, and both ends of the steel bars protrude from both ends of the steel pipe by the length of reinforcing bars. Single cast-in-place pile foundation. Excavating the site floor to which the pile foundation is to be installed using a drilling rig; Inserting a steel cage into which the steel pipe mounting plate is coupled to the excavated space; Inserting the steel pipe into the reinforcing cage and placing the steel pipe in the center of the steel pipe mounting plate so that the steel pipe is disposed over the upper end of the pile and the lower end of the piers; Reinforced single site casting pile foundation construction method comprising the step of curing by pouring concrete in the outer space of the steel pipe. 10. The method of claim 9, wherein the steel pipe is a corrugated steel pipe whose outer circumferential surface is curved in a wavy shape, and concrete is poured into the corrugated steel pipe.

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