JPS5850218A - Connecting structure system for head of cast-in-place concrete pile and footing - Google Patents

Abstract

PURPOSE:To obviate the needs to chip extra-branking concrete formed on the head of a pile by a method in which an iron bar cage is set in the hole of the pile, concrete is placed to the bottom level of a footing, a connecting precast pile is inserted, and then the footing is cast on the connecting precast pile. CONSTITUTION:A pile pit 1 is drilled, an iron bar cage 2 is set in the hole, and concrete 3 is placed to a level L corresponding to the bottom of a footing. Then, an excavating casing is drawn out, a connecting precast pile 5 is vertically inserted into the center of the uncured concrete 3 in the pit 1, and then a hung rope 6 provided on the upper end of the precast pile 5 is coupled with a supporting bar 7. Soil on the level L is removed, the top sides 8 and 9 are chipped horizontally, formwork is set for footing, concrete 10 is placed into the formwork and hardened, and then soil G1 is back filled. Thus, since loads are all burdened by the pile 5, extra-banking faulty concrete C plays a role on safety side and thereby the need for chipping the concrete is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for connecting the head of a cast-in-place concrete pile to a foundation footing.

Cast-in-place concrete piles have relatively little noise and vibration;
Although it is widely used and has many advantages such as a large bearing capacity per pile and the ability to choose the diameter according to the load, there have been various problems with the processing of the pile cap.

Therefore, I will explain the conventional method. First, a foundation pile hole is excavated using an auger machine, and reinforcing bars are inserted into this hole.
Concrete is poured using tremie pipes. Then, after removing the excavation casing, filling the soil, and cutting the roots, the defective excess concrete at the top end was removed by grinding.
After laying gravel and sacrificial concrete, the footings are reinforced, the formwork is constructed, and the footings are poured into the formwork.

By the way, the drawbacks of this conventional method include the following.

■ Defective concrete IJ-to (500~10
00 m), the construction period for the chisel work is 8 shun,
Furthermore, the noise and vibrations associated with this construction work are a pollution problem, and complaints may be received from nearby residents.

■ Countermeasures against problems such as hole wall collapse or concrete overhang during construction of cast-in-place concrete piles are difficult to deal with, and conventionally, the only way to deal with these problems has been to increase the number of piles.

■ The length of the ib corner is likely to be too long or too short due to the slope or unevenness of the supporting ground.

■ The reinforcing bars at the pile head are deformed. ■ Since the pile diameter is determined by the supporting ground conditions, the shape of the foundation footing also becomes larger.

■ It is difficult to take countermeasures when the top of the pile is deeper than the specified depth due to a measurement error.

■ It is difficult to use the joint between the pile and foundation footing as a hinge or as a fixation. Therefore, the present invention is intended to eliminate the drawbacks of the above-mentioned prior art, and will be described in detail with reference to the drawings.

In FIG. 1, a pile hole 1 is drilled using an earth drill at a predetermined position G where a foundation pile is to be constructed.

Therefore, reinforcing bars 2 are inserted into hole 1, and concrete 3 is raised to level L corresponding to the bottom of the footing using a tremie pipe.
Then, the excavation casing 4 is pulled up and removed.

Next, as shown in FIG. 2, a ready-made connecting stake 5 is vertically inserted into the center of the hole 1 and set. This ready-made pile 5 is made of a steel pipe concrete pile or a steel pipe pile, and a sill bevel 5a is protruded from the outer periphery thereof as necessary. A suspension rope 6 is provided at the upper end of the ready-made pile 5 and is engaged with a support bar 7, thereby holding the ready-made pile in a predetermined position on the concrete until the concrete 3 hardens. Then, by filling in the soil and cutting the roots, the mud was removed as shown in Figure 3, and the Tenjiku 8
゜9゜Comb horizontally.

After that, the footing is reinforced and the formwork is assembled.

Then, footing concrete 10 is poured into the formwork,
When this concrete 131 hardens, it will be in the state shown in Figure 4. After that, as shown in Figure 5, all the steps are completed by backfilling with 11KGl of soil.

In the foundation footing P completed according to the present invention, the soil load is entirely borne by the ready-made connecting piles 5.
Although the rank concrete C with poor reinforcement shown in FIG. 5 is not designed to bear any load, it is effective on the safety side and in preventing rust, passive earth pressure, and buckling.

Next, processing for troubles during construction according to the present invention will be explained. - Figure 6 shows a case where the reinforcing bars 2 inserted into the concrete are too deep and become short, but the ready-made connecting piles 5 are lengthened accordingly. 1! is a pillar.

Fig. 7 shows a case where trouble occurs in the hole l wall, but even if a gap 12.13 occurs, it is possible to prevent the hole wall from collapsing using the connecting prefabricated piles 5 and to be able to sufficiently support the stress. can.

Figure 8 shows that when a pillar 11 is installed near the site boundary line N, the axes of the pillar and the ready-made pile 5 may not match, but in this case, the inserting position of the ready-made pile is shifted from the center of the hole 1. The eccentricity is made to coincide with the axis of the column, and by shortening the eccentric distance between the column 11 and the pile 5, stress can be transmitted smoothly.

Since the present invention has the above-mentioned configuration, first of all, the lifting work can be drastically reduced, pollution caused by noise and vibration can be prevented, the construction work can be shortened, and even if troubles such as hole wall collapse occur, it is possible to make long ready-made piles for connection. It is easy to handle, there is no need to worry about the length of reinforcing bars being too long or too short, and the foundation footing is smaller than before, and there is no need for waste concrete, concrete, or gravel, and concrete for cast-in-place concrete piles can be easily handled. ,
It also reduces the amount of reinforcing bars used, improves safety in concrete areas with poor reinforcement, and allows for mass production of ready-made piles for connections in factories. Furthermore, it is easier than before to freely select the members of the ready-made pile for connection and to move the pile head closer to the hinge according to changes in the load and stress on the pile head.

[Brief explanation of drawings]

FIGS. 1 to 5 are cross-sectional views showing the construction method of the present invention step by step, and FIGS. 6 to 8 are cross-sectional views showing examples of cases where construction trap troubles occur. l...hole, 2...reinforced cage, 3...concrete, 5...ready-made pile for connection, 6...hanging rope, 7...
・Support bar, 10...Footing concrete, L・
...At the level of worshiping at the bottom of the footing. Above Figure 3 Figure 4

Claims (1)

[Scope of Claims] Concrete is poured into the pile hole using a reinforcing bar cage device to a level corresponding to the bottom of the footing, and ready-made piles for connection are inserted vertically into the pile hole, and this is continued until the concrete hardens. The process of supporting the prefabricated piles, removing the mud around the upper opening of the pile hole after the concrete has hardened, arranging footing reinforcement, constructing a formwork, and pouring footing concrete into this formwork. A connection structure method between the head of a cast-in-place concrete pile and a foundation footing, characterized by comprising: