JPH028089B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method of constructing a pile foundation reinforced against horizontal force, and its purpose is to reinforce the required length of the upper part of the pile so as to sufficiently withstand horizontal force, and to strengthen the hollow part of the pile. , concrete is poured into the casing together with the footing using connecting hardware, improving construction efficiency. Alternatively, the casing and the pillar can be connected together with the footing to improve construction efficiency.

Conventionally, anchor reinforcing bars have been installed to secure the pile head to the footing, but this may not be sufficient considering the bending moment of the pile part caused by pull-out force and horizontal force. Then, the prestress decreases, which becomes more of a problem.

Therefore, structures have been developed in which a casing or steel pipe is fitted around the outer circumference of the pile head in advance or afterward to reinforce the pile head or the upper part of the pile. There is a method shown in the publication.

By the way, in the case shown in the former publication, only the joint of the pile head is reinforced, and the short steel pipe does not penetrate into the ground and has no reinforcing effect on the pile material, and furthermore, filler is filled between the pipe and the casing first. This increases construction time. Furthermore, in the case shown in the latter publication, the casing is driven in first, so there is a risk that earth and sand may enter the casing and damage the casing, and there is also a risk that the casing may move during pile driving. Furthermore, it is difficult to discharge the earth and sand inside the casing.

The present invention was developed to solve the above-mentioned conventional problems and to securely secure the foundation by providing a connecting hardware protruding from the casing.The details of the invention will be explained below with reference to the illustrated embodiments.

First, a hollow pile 1 with an open top is erected into the ground at a desired position by driving or the like. Then the pile 1
Guided by this, a cylindrical casing 4 with a partial bottom 3 is built by driving or the like into the ground at the outer periphery of the upper part of the pile where the influence of horizontal force is large, so that the tip part closes the gap with the pile. The length of the casing should be approximately 3 to 8 times the diameter of the pile, and should be selected depending on the soil and pile material.

Further, in order to increase the reinforcing effect of the pile head, a connecting hardware 5 such as a gusset plate is provided protruding from the outer periphery of the casing 4, and a reinforcing material 6 for the underground beam is attached. A plugging material 7 is placed inside the pile, and concrete 9 is placed inside the pile 1 and the casing 4 together. Further, a plate 8 may be provided at the top of the pile, and then the base plate 11 of the steel column 10 may be superimposed on the plate 8 and connected with bolts and nuts. Next, concrete for the footing portion 12 is poured. Fourth
Fig. 5 shows other embodiments of the footing part, and Fig. 4 shows the casing 4 attached to the footing part 1.
Fig. 5 is an example in which the reinforcing bars 13 are raised from the connecting hardware 5, and both are raised to the top of the steel frame column 10.
This is an example in which the base plate 11 is installed on the footing part 12. 6 and 7 show a state in which the closing member 7 is suspended by a chain 16 from a mounting rod 15 inserted into the upper part of the casing 4. A plurality of insertion holes for the mounting rods 15 are provided so that the height of the plug can be adjusted. In addition, the connecting metal fitting 5 has an angle material 17 that becomes the upper and lower chord members of the lattice beam.
In this case, the underground beam can be made of SRC structure.

This invention has the above-mentioned structure, and a cylindrical casing is built in the ground at the outer periphery of the upper part of the pile where the horizontal force of a hollow pile with an open top is large, and concrete is placed inside the hollow of the upper part of the pile and inside the casing together with the footing. Since it is cast into one piece, construction is completed in one step, and the ground around the outer periphery of the pile head is consolidated, resulting in a significant improvement in bearing strength. In addition, since the concrete is placed deeper inside the pile than the bottom end of the casing, there are no sudden changes in the cross section, and there is less stress concentration, so the resistance to horizontal forces is reasonable. Furthermore, since the casing is erected using the piles as guides after the piles are erected, there is no risk of damage to the casing, and there is no fear of the casing moving, making it easy to center the piles and the casing.

In particular, in this invention, by providing a connecting hardware protruding from the casing, it is possible to connect the reinforcing bars or steel frames of the underground beams to ensure the anchorage of the foundation. It is also possible to connect the columns directly onto the casing to ensure the integrity of the columns and piles.

[Brief explanation of drawings]

Figures 1, 2 and 3 are longitudinal sectional views of the construction process; Figures 4 and 5 are longitudinal sectional views of other embodiments;
FIG. 6 and FIG. 7 are a longitudinal cross-sectional view and a cross-sectional view showing different embodiments of the casing portion. 1...Pile, 3...Bottom, 4...Casing, 5...
...Connecting hardware, 6...Reinforcement material, 7...Closing material, 8
... Plate, 9 ... Concrete, 10 ... Steel column, 11 ... Base plate, 12 ... Footing part, 13 ... Reinforcement bar, 14 ... Reinforcement bar, 15 ...
Mounting rod, 16...chain, 17...angle material.

Claims (1)

[Scope of Claims] 1. A hollow pile with an open top is erected at a desired position, and then the pile is used as a guide to place the tip on the outer periphery of the upper part of the pile, where horizontal force is large, so as to close the gap between the pile and the pile. A cylindrical casing with a cylindrical shape is erected into the ground, and a connecting hardware is protruded from the cylindrical casing, and the inside of the hollow above the pile above the closing material located below the cylindrical casing, the inside of the casing, and the footing are A construction method for pile foundations that is reinforced against horizontal forces and is characterized by pouring concrete into one piece. 2. A hollow pile with an open top is erected at the desired position, and then, using the pile as a guide, a cylindrical casing with the tip end closing the gap between the pile and the pile is placed around the outer periphery of the top of the pile, which is susceptible to horizontal forces. It is built into the ground, a column is connected on top of the cylindrical casing, and concrete is cast in the hollow above the pile above the closing material located below the cylindrical casing, inside the casing, and at the footing to form an integral structure. A construction method for pile foundations that is reinforced against horizontal forces. 3. A hollow pile with an open top is erected at the desired position, and then, using the pile as a guide, a cylindrical casing with the tip end closing the gap between the pile and the pile is placed around the outer periphery of the top of the pile, where horizontal forces are most likely to affect the pile. It is built into the ground, and the reinforcing bars of the underground beam and the anchor reinforcing bars are connected to the connecting fittings protruding from the cylindrical casing, and the hollow part above the pile above the closing material located below the cylindrical casing and inside the casing. and a method of constructing a pile foundation reinforced against horizontal forces, which is characterized by pouring concrete in the footing and making it integral.