JPS61216960A - High strength structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a high-strength structure used for piles, columns, etc. that are subjected to large axial compressive forces.0 Prior Art Piles, columns, etc. are subjected to large axial compressive forces. , extremely high strength is required. In order to obtain high strength, it is sufficient to make the structure itself large and thick, but on the other hand, piles, columns, etc. are used in places where space is limited.
A problem arises in that extremely large diameter holes cannot be used, and the cost increases significantly due to the drilling of large diameter holes and the use of large construction machines.

Structures have been developed in which load-bearing steel materials such as Concrete IJ + Concrete Q are filled with cement-based hardening materials.

The structure is made of steel pipes and load-bearing steel materials to withstand tensile forces, and cement-based hardening materials to withstand compressive forces, resulting in extremely high strength.

Problems to be solved by this invention However, especially when using high-strength reinforcing bars as load-bearing steel materials, there is a large difference in strength between the reinforcing bars and concrete.
There is a problem in that the reinforcing bars cannot follow the expansion and contraction of the concrete, and as shown in Figure 7, the adhesion between the concrete and the reinforcing bars breaks.

For example, the compressive strength of concrete has increased from 200 to 4009/
, L2, the allowable stress level of the reinforcing bars is 1800~2200''/
It is possible to fix reinforcing bars with an adhesion length of several tens of centimeters when the reinforcing bars have an adhesion length of about 5,000 cm2.
If it is about 0 to 1o, o o o Kv/, 2 or more, a fixing length of 5 m or more is required due to the difference in strength and the progression of adhesion breakage.

Specifically, if there is a structure with a length L of 6 m as shown in Figure 8, this means 5rrL on one side from the center of the member.
Each part becomes the fixed part, that is, the attachment length. This means that the attachment length of the reinforcing bars must be 3 m to withstand the reinforcing bar stress generated by the maximum bending moment at the center of the structure. Conversely, this means that the length of the member cannot be made shorter than this.

If the structure is made shorter than this, the reinforcing bars contained within it will be released from the restraints of the concrete from the initial position shown in Figure 6 to the upper The reinforcing bars placed on the compression side will protrude outward, and the reinforcing bars placed on the lower tension side will be pulled inward.

Therefore, the attachment length of the reinforcing bars is too short to ensure fixation in the member, and the concrete and reinforcing bars cannot function as one, resulting in a significant deterioration of the properties of the structure.

In order to improve these problems, there are inventions in which nuts are screwed onto the ends of load-bearing steel materials, or welded to steel pipes, so that the steel material follows the bending and tension of the entire material to prevent bond breakage. .

However, although screwing a nut together is effective in the tensile or pulling direction, it is not effective in the compression or protruding direction, and welding is effective in both cases, but it is effective for steel materials. There is a problem of degrading the quality of the material.

Means for Solving the Problems This invention provides a method in which fixing portions are provided protruding from the inner periphery of both ends of a steel pipe,
Insert the end of the load-bearing steel material disposed inside the steel pipe, on which a male screw is threaded on the outer periphery, into the insertion hole formed in the fixing section, and insert the end with a nut from both left and right sides of the fixing section. By fixing the parts in the fixing part and filling the steel pipe with a cement-based hardening material, the steel can be made to follow the bending of the structure without degrading the quality of the load-bearing steel.

EXAMPLE The present invention will be described in detail below based on an example shown in the drawings.

In the figure, 1 is a steel pipe. The steel pipe 1 can be of various shapes such as cylindrical and prismatic.

Fixing portions 2 are provided protruding from the inner periphery of both ends of the steel pipe 1, respectively. In the embodiment, the fixing section 2 is a ring-shaped plate attached to the inner flange.

A plurality of insertion holes 3 are formed in the fixing portion 2 at appropriate intervals in the circumferential direction. An end portion of a load-bearing steel material 4 disposed within the steel pipe 1 is inserted into the insertion hole 3 of the fixing portions 2 , 2 . As the load-bearing steel material 4, in addition to ordinary reinforcing bars, high-strength deformed steel bars, stranded steel wires, etc. can be used.

Male screws 5 are screwed on the outer periphery of both ends of the load-bearing steel material 4, and nuts 6.6 located on both sides of the fixing part 2 are screwed into the male screws 5 of the load-bearing steel material 4, thereby fixing the steel material 4. .

The steel pipe 1 as described above is filled with a cement hardening material 7 such as concrete or mortar.

The high-strength structure according to the present invention has the above configuration, and when bending stress occurs in the structure, since both ends of the load-bearing steel 4 are firmly fixed to the steel pipe 1, the structure 1 It expands and contracts as it bends, making it difficult for adhesive breakage to occur.

Therefore, even if the length of the structure itself is short, the load-bearing steel material 4 will not lose its original function.

The fixing section 2 may be fixed to the steel pipe 1 before the load-bearing steel material 4 is fixed. Also, both ends of the load-bearing steel material 4 are fixed to the fixing section 2 with nuts 6.6 in advance, and then the fixing section 2 is fixed to the steel pipe 1. 2 may be fixed to the steel pipe 1 by welding.

Effects of the Invention This invention has the above-mentioned configuration, and since a fixing device is fixed to the inner periphery of both ends of a steel pipe and a load-bearing steel material is fixed to the fixing device with a sut, the quality of the load-bearing steel material is not deteriorated. In addition, the length of the structure itself can be shortened because it can sufficiently follow the expansion and contraction of the entire structure and less breakage of adhesion to the hardening material.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of one embodiment of the high-strength structure of the present invention, FIG. 2 is a partially enlarged view thereof, and FIGS. 3 to 5 are DI-m, IV-IV, 6 and 7 are longitudinal sectional views of the conventional example, and FIG. 8 is an explanatory diagram showing the bending moment of the structure. 1. Steel pipe, 2. Anchoring part, 3. Through hole, 4. Load-bearing steel material, 5. Male thread, 6. Nut, 7. Cement hardening material. Figure 6 Figure 7 Figure 8 Procedural amendment May 1985 IEI Qin

Claims (1)

[Claims] Fixing parts are provided protruding from the inner periphery of both ends of the steel pipe, and the ends of the load-bearing steel material disposed inside the steel pipe, each of which has a male screw threaded on the outer periphery, are inserted into the insertion holes formed in the fixing parts. 1. A high-strength structure, characterized in that the steel pipe is inserted through the steel pipe, the ends are fixed to the fixing part with nuts from both the left and right sides of the fixing part, and the steel pipe is filled with a cement-based hardening material.