JP2000080646A - Interlocking cast-in-place pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the cost and to improve the strength of a pile by combining multiple reinforcing cages constituted of multiple main reinforcements and horizontal restraining reinforcements arranged around the main reinforcements partially overlappingly on the cross section, and forming the cross section of the pile in the overlapped shape of the reinforcing cages. SOLUTION: Multiple reinforcing cages 2 are simply combined, then the main reinforcements at the overlapped portion are thinned out. When two reinforcing cages 2 are combined, for example, execution is applied by the reverse circulation drill method with an excavator having two excavation shafts. Even when three sets of reinforcing cages 2 are combined in one direction, an execution machine constructing a continuous wall such as SMW is used, or a continuous hole is formed into a wall shape by an improved excavator with a circulating endless chain for execution. Main reinforcements 3 are inserted and arranged between the horizontal restraining reinforcements of multiple reinforcing cages 2, and the restraining effect of concrete 8 by the reinforcing cages 2 can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast-in-place pile in which resistance to a bending moment during an earthquake is enhanced by a restraining effect.

[0002]

2. Description of the Related Art
Level 2 on pile foundations since the revision of the Highway Bridge Specification in 2010
Seismic design against seismic motion is being obligated, and according to the design, the amount of reinforcing bars of a rank that is about two ranks higher than the design based on the conventional seismic intensity method is required.

[0003] From this, if a conventional cast-in-place pile maintains a circular cross section, the main reinforcement becomes too large and dense, and it becomes difficult to connect the footing to the reinforcing steel. Quality may be reduced. Increasing the number of piles without increasing the amount of main reinforcement in the cross section of the pile would increase the cost.

[0004] In view of the above background, the present invention proposes a cast-in-place pile that improves the yield strength while keeping the main bars from becoming dense and suppressing costs.

[0005]

According to the present invention, a plurality of sets of reinforcing bars composed of a plurality of main bars and lateral restraining bars (band reinforcing bars) arranged around the main bars are combined, and the plurality of sets of reinforcing bars are combined. By forming the cross-section of the pile in a given shape, the strength of the pile is improved while keeping the main bars dense and suppressing the cost.

A plurality of sets of reinforcing bars are partially overlapped with each other on the cross section, and by overlapping with each other, the main bar is inserted between the lateral restraining bars (band reinforcing bars) of the plurality of sets of reinforcing bars at the overlapping portion. Since the reinforcing bars are arranged so that the reinforcing bars are restrained from each other, the reinforcing effect of the reinforcing bars on the concrete increases.

[0007] Further, since the amount of main reinforcing bars as one pile is twice as many as the number of pairs of reinforcing bars, the strength against bending moment is increased, and the toughness is improved in addition to the restraining effect of concrete.

Since the cross-sectional shape of one cast-in-place pile is not circular, but a plurality of sets of reinforcing cages are overlapped, for example, a plurality of circular shapes are overlapped. However, since the main reinforcement is not densely arranged, it is not difficult to connect the footing to the reinforcing steel, and the problem of deterioration in workability and the deterioration of the quality of the foundation due to the deterioration can be avoided.

In addition, since the cast-in-place pile has a shape in which a plurality of sets of reinforced cages are overlapped, the cross-sectional area is smaller than in the case of constructing a plurality of independent piles, thereby suppressing an increase in construction cost.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a plurality of sets of reinforcing bars 2 and 2 are partially overlapped with each other in cross section, and the sets of reinforcing bars 2 and 2 are overlapped. It is a cast-in-place pile 1 having a shape of a cross section.

The reinforcing rod cage 2 is assembled into a cylindrical shape from a plurality of main reinforcing bars 3 and lateral restraining bars (band reinforcing bars) 4 arranged around the main reinforcing bars 3. Fig.2, Fig.6-
As shown in (g), the lateral restraint bars (band bars) of each reinforcing bar cage 2 and 2
The reinforcing bars 4 and 4 are combined so as to be staggered to form the reinforcing bar basket group 5. A hoop is used as the lateral restraining bar (band reinforcing bar) 4 in addition to the spiral bar as shown in FIG.

The reinforcing bar cage 2 is assembled at a factory or a site. When a spiral bar is used as the horizontal restraining bar (band reinforcing bar) 4, the horizontal restraining bar (band reinforcing bar) 4 wound in a coil shape in advance is used. Is stretched in the axial direction, and a plurality of stretched lateral restraint bars (band reinforcing bars) 4 and 4 are overlapped with each other. Then, the main bar 3 is inserted in the axial direction and bound to the horizontal restraining bar (band reinforcing bar) 4. Or by welding, the reinforcing bar basket group 5 is assembled. When the lateral restraining bars (band reinforcing bars) 4 are hoops, the horizontal restraining bars (band reinforcing bars) 4 and 4 are overlapped with each other and the main bars 3 are attached.
Is arranged in the same manner.

FIGS. 1 and 2 show a case where two sets of reinforcing bars 2 and 2 are combined to form a reinforcing basket group 5, and FIGS. 3 and 4 show a case where three sets of reinforcing bars 2 and 2 are combined. Show. FIG. 3 shows a case where three sets of reinforcing rod cages 2, 2, 2 are arranged in one direction.
Is a case where three sets of rebar baskets 2, 2, 2 are combined so that one set of rebar baskets 2 overlaps the other rebar baskets 2, 2 evenly.

When a plurality of sets of reinforcing bars 2 are simply combined, the amount of the main bars 3 as one pile is twice as many as the number of pairs of reinforcing bars 2 to be combined. From the simple combination of the pair of reinforcing bars 2,
Is thinned out at the overlapping part of the main bar 3.

The construction method of the cast-in-place pile 1 is as follows.
That is, it depends on the number of combinations of the reinforcing bars 2 and how to combine them. When two sets of reinforcing bars 2 are combined,
For example, it is constructed by a reverse circulation drill method using an excavator 9 having two excavating axes shown in FIG. When three sets of rebar cages 2, 2, 2 are combined in one direction, a wall-shaped continuous hole is formed by a construction machine that builds a continuous wall such as an SMW or an excavator that improves the circulating endless chain. Is constructed.

As shown in FIG. 4, three sets of reinforcing rod cages 2, 2, 2
Is combined with a single-shaft excavator or a combination of a single-shaft and a twin-shaft excavator. In other words, a cast-in-place pile having a circular cross-section and a cast-in-place pile 1 having a cross section shown in FIG.

FIG. 5 shows a case where the cast-in-place pile 1 is constructed by dropping the reinforcing bar cage group 5 into the borehole 7 formed by the reverse circulation drill method and placing concrete 8 as a filler into the borehole 7. Show.

In this case, the ground is excavated by the excavator 9.
(a) After the excavation is completed, remove the slime and measure it. (b)
The reinforced basket 5 is built in the borehole 7 and
Concrete 8 is poured through the concrete (c).
After the installation is completed, the stand pipe 11 is pulled out to complete the construction (d).

FIG. 6 shows a construction in which the cast-in-place pile 1 is combined with the underground beam 6.

[0020]

According to the present invention, a plurality of reinforcing bars composed of a plurality of main reinforcing bars and lateral restraint bars (band reinforcing bars) arranged around the main reinforcing bars are partially overlapped with each other on the cross section, and the overlapping portions are combined. In this case, the main reinforcing bars are inserted between the horizontal restraining bars (band reinforcing bars) of the plurality of sets of reinforcing bars so as to arrange the reinforcing bars, so that the restraining effect between the reinforcing bar cages is increased, and the restraining effect of the concrete by the reinforcing bar cages is enhanced.

Further, since the amount of main reinforcing bars as one pile is twice as many as the number of pairs of reinforcing bar cages, the strength against bending moment is increased, and the toughness is improved in addition to the restraining effect of concrete.

Since the cross section of a single pile is not circular but a plurality of sets of reinforcing bars overlap each other, the main bars do not become dense even though the amount of main bars increases. The connection with the reinforcing steel does not become difficult, and the problems of deterioration in workability and deterioration in foundation quality are avoided.

Further, since a plurality of sets of rebar cages have an overlapping shape, the cross-sectional area can be smaller than in the case of constructing a plurality of independent piles, thereby suppressing an increase in construction cost.

[Brief description of the drawings]

FIG. 1 is a plan view showing a cast-in-place pile when two sets of reinforcing bars are combined.

FIG. 2 is a perspective view showing a state where two sets of reinforcing bars are combined.

FIG. 3 is a plan view showing a cast-in-place pile in a case where three sets of reinforcing bars are combined.

FIG. 4 is a plan view showing another cast-in-place pile in a case where three sets of reinforcing bars are combined.

5 (a) to 5 (d) are elevation views showing a procedure for constructing a cast-in-place pile by a reverse circulation drill method.

FIG. 6 is a plan view showing a state where a cast-in-place pile is constructed in combination with an underground beam.

[Explanation of symbols]

1 ... cast-in-place pile, 2 ... reinforced cage, 3 ... main bar, 4 ...
Lateral restraint bars (band reinforcing bars), 5 …… reinforcing bars, 6 …… underground beams,
7 ... drilling, 8 ... concrete, 9 ... excavator, 10 ...
... Tremy tube, 11 ... Stand pipe.

Claims (1)

[Claims] 1. A plurality of sets of reinforcing bars, which are composed of a plurality of main reinforcing bars, lateral restraining bars (band reinforcing bars) arranged around the main reinforcing bars, and are inserted into the drilling holes, and are filled in the drilling holes. An interlocking cast-in-place pile composed of a filler material, wherein the plurality of sets of reinforcing bars are partially overlapped with each other on a cross section, and the plurality of sets of reinforcing bars have an overlapping cross-sectional shape.