JPH05140954A - Structure of part near head of pc pile - Google Patents

Abstract

PURPOSE:To improve the safety and easiness in works of extending mild steel bars for fixation from the head of a PC pile, such extension being required when construction works are executed in the neighborhood of the pile head in the pile foundation. CONSTITUTION:A ring-form end plate 2 is fixed to the head of a PC pile 1 and provided with a plurality of threaded holes 3a, 3b. The threaded hole 3a is blocked with the head of a PC steel material 4 arranged at the PC pile 1 in tone condition that the PC pile is embedded in the ground, while the other 3b remains out of blocking to admit driving of a fixation rod 5. According to the conventional technique, such a fixation rod 5 is connected with the end plate 2 by welding and it involves risk of current leak accident, but this new system improves the safety and easiness in works.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure near a head of a PC pile which constitutes a pile foundation of a building.

[0002]

2. Description of the Related Art A pile foundation is one in which a foundation slab is supported by piles buried in the ground. As a method of joining the pile and the foundation slab, for example, a pile head in concrete which becomes the foundation slab is used. The method of shortening the burial length and extending the reinforcing bars upward from the pile head is adopted.

On the other hand, in the pre-tensioning type PC pile, fixing plates for fixing the PC steel material and applying tension to the PC steel material are installed at both ends of the frame during the forming by centrifugal force. Conventionally, in the pile foundation with this pre-tensioned PC pile,
When the pile and the foundation slab are joined by the method described above, the fixing plate installed at the end of the formwork on the side that will be the head of the PC pile at the time of manufacturing is left as it is as the end plate, and the PC pile is grounded. After the embedding, fixing bars were welded to this end plate.

[0004]

However, when welding the reinforcing bar to the end plate of the head of the buried PC pile, it is not uncommon for an electric leakage accident to occur. Further, since the welding operation itself is complicated, the conventional method has problems in safety and workability. The present invention is intended to solve such a problem, and is a PC for a pile foundation.
An object of the present invention is to improve the safety and workability of the work of extending the reinforcing bar from the head of the PC pile in the construction of the structure near the pile head.

[0005]

In order to achieve the above object, the present invention secures the lower end of a fixing bar extending upward to an end plate fixed to the head of a PC pile, and surrounding the fixing bar. Pour foundation concrete into the base and fix PC piles to the foundation P
In a structure near a C pile head, a structure near a PC pile head is characterized in that a lower end portion of the anchorage is screwed into a screw hole formed in the end plate.

[0006]

In the structure of the present invention, the work of extending the fixing reinforcing bar from the head of the PC pile is completed by screwing the lower end of the fixing bar into the screw hole formed in the end plate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view of a PC pile in which an end plate is fixed to a head portion, FIG. 2 is a sectional view taken along the line AA in FIG.
Is a cross-sectional view showing an outline of a pile foundation having a structure of the present invention, FIG. 4 is an enlarged view of a portion C of FIG. 3, and FIG.

In this embodiment, the fixing plate used when manufacturing the PC pile 1 by the pre-tension system is used as the end plate 2 of the PC pile head as it is. As can be seen from FIGS. 1 and 2, this fixing plate is a ring having a plurality of screw holes 3a and 3b, and its outer diameter and inner diameter are equal to the outer diameter and inner diameter of the PC pile 1. Then, a predetermined number of PC steel materials 4 according to the type of PC pile to be manufactured are fixed to a part of the plurality of screw holes 3a and 3b by a conventionally known means. In FIG. 1, the screw hole 3a to which the PC steel material 4 is fixed is painted black.

The remaining screw holes 3b are used for fixing the fixing plate to the reaction force device with a bolt and pulling the fixing plate to the outside when the PC pile is manufactured. Then, by pulling the fixing plate outward, prestress is applied to the PC steel material fixed in the screw hole 3a. When the manufacturing of the PC pile is completed, the bolts are removed to separate the fixing plate from the reaction device. Therefore, in the completed PC pile 1, the screw holes 3a are
Although closed by the head of the steel material 4, the screw hole 3b is an open hole. In the present embodiment, the screw hole 3b, which is the open hole, is screwed with the fixing streak 5 having the corresponding male screw 5a at one end.

The structure of the present invention is constructed, for example, by the following method. As shown in FIG. 1, the PC pile 1 used here has a fixing plate having 16 screw holes 3a and 3b as an end plate 2, and six PC steel materials 4 are arranged therein, and a pretension system is used. The manufactured outer diameter is 300 mm. The shapes of the screw holes 3a and 3b are represented by circles for convenience. The root diameter of the screw hole 3b into which the fixing bar 5 is screwed is 22 mm, and a 700 mm long rebar having a male screw corresponding to this screw hole 3b at its end was used as the fixing bar 5. First, in the end plate 2 of the head of the PC pile 1, ten screw holes 3b, which are open holes, are closed and protected with an adhesive cloth tape or the like. In this state, the PC pile 1 is embedded in the ground 6 by a conventionally known means such as the Nakabori construction method, and the pile head is placed at a predetermined position. After that, the soil around the buried PC pile 1 is excavated, root cutting is performed up to the line B in FIG. 3, and then discarded concrete 7 is placed on it.

Here, as shown in FIG. 4, a vertical dimension D between the upper surface of the discarded concrete 7 and the head end surface of the PC pile 1.
Corresponds to the pile head burial length in the foundation concrete 8 that is placed above the discarded concrete 7. Therefore, it is necessary to perform the above-mentioned root cutting and pouring of the discarded concrete 7 so that the pile head burying length becomes a predetermined value. At this time, cement milk or soil for rooting is put in the inside 1a of the hollow PC pile 1, but the upper surface of the cement milk or soil is discarded to secure the pile head burial length D here as well. Dig along with the top surface of concrete 7.

After the above work is completed, the PC is buried.
The head of the pile 1 is cleaned and the adhesive cloth tape that has blocked the screw hole 3b is removed. Then, as shown in FIG. 5, by using a pipe wrench 9 or the like, a male screw at the lower end of the fixing streak 5 is screwed into the screw hole 3b to extend ten fixing streaks 5 upward from the end plate 2. In the present invention, the fixing muscle 5 can be extended from the head of the embedded PC pile 1 by such a simple operation. Further, in this embodiment, the PC steel material 4 of the end plate 2 is not fixed to the screw hole 3
By utilizing b, the fixing line 5 can be screwed into this.

In this way, all the fixing streaks 5 are attached to the end plate 2.
After finishing screwing into the screw hole 3b, a predetermined amount of basic concrete 8 is placed on the upper side of the discarded concrete 7 to complete the structure near the PC pile head of the present invention. Thereby, the foundation concrete 8 and the PC pile 1 are integrated, and the foundation concrete 8 is supported by the PC pile 1.

[0014]

As described above, according to the present invention, the lower end portion of the fixing muscle is screwed into the screw hole formed in the end plate fixed to the head of the PC pile, so that the PC
The work of extending the anchoring streak from the head of the pile can be easily performed. Further, unlike the conventional welding work, there is no risk of electric leakage and the work can be performed safely. As a result, the work efficiency is improved and the construction cost of the PC pile foundation can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a PC pile according to this embodiment.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a cross-sectional view showing an outline of a pile foundation having the structure of the present invention.

FIG. 4 is an enlarged view of a portion C in FIG.

FIG. 5 is a schematic view showing a construction example of the structure of the present invention.

[Explanation of symbols]

 1 PC pile 2 End plate 3b Screw hole 5 Anchorage 8 Basic concrete

Claims (1)

[Claims] 1. A lower end of a fixing bar extending upward is fixed to an end plate fixed to a head of a PC pile, and foundation concrete is driven around the fixing bar to fix the PC pile to the foundation P.
In the structure near the C pile head, the structure near the PC pile head is characterized in that the lower end portion of the anchorage is screwed into a screw hole formed in the end plate.