JP2003013496A - Prestressed concrete structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prestressed concrete structure that does not lose its soundness and assets value as wells as the safety of human life even when a large earthquake exceeding moderate earthquakes occurs. SOLUTION: This prestressed concrete structure 1 is constructed by spanning the spaces among precast concrete columns 2 erected on a foundation 6 with precast concrete beams 3 by putting the joining end sections of the beams 3 on the beam receiving jaws 12 of the columns 2. Then PC steel 4 wired between the beams 3 and columns 2 is tensed with an effective tensile force which is about 30-60% of the yield strength of the PC steel 4.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a prestressed concrete structure.

[0002]

2. Description of the Related Art Since the current design standards for seismic structures are for horizontal ocean earthquakes, they allow a damage limit before a building cannot be reused. A prestressed precast concrete column and a prestressed precast concrete beam are used as one of the seismic structures constructed under this design standard.
There is a prestressed concrete structure that is joined with C steel. PC steel materials are used for joining the members of the prestressed concrete structure, that is, joining the precast concrete columns to the foundation and joining the precast concrete columns to the precast concrete beams.
Rigid joints tensioned with an effective tension of 80% of steel yield strength have become standard.

[0003]

However, the above-described prestressed concrete structure has a level 1 (20-
Corresponding to a medium-scale earthquake of 25 cm / sec) as a rigid joint structure, but a large-scale earthquake of level 2 (40 to 50 cm / sec) or a large earthquake of level 3 (60 to 75 cm / sec) is a rigid joint structure. I could not deal with it as a structure,
There was a risk that the PC steel material would yield and damage the precast concrete columns and precast concrete beams. Although such a structure is not a problem from the viewpoint of safety of human life, there is a fear that the soundness of the building and the asset value may be deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to be able to cope with a large earthquake exceeding a medium earthquake, and not only safety of human life but also soundness and asset value. The purpose is to provide a prestressed concrete structure that does not lose.

[0005]

According to the invention of claim 1 for solving the above problems, a precast concrete beam is erected between precast concrete columns erected on a foundation, and a joint end portion of the precast concrete beam is PC steel material installed in the beam receiving jaw of the precast concrete column and wired between the precast concrete beam and the precast concrete column has a PC steel yield strength of 3
It is characterized by having an effective tension of 0 to 60%.
Further, the invention of claim 2 is characterized in that, in claim 1, the PC steel material wired between the foundation and the precast concrete column is tensioned with an effective tension of 30 to 60% of the yield strength of the PC steel material. The invention of claim 3 is characterized in that, in claim 1 or 2, the effective tension of the PC steel material wired between the precast concrete beam and the precast concrete column is changed according to the story height. Further, the invention of claim 4 is characterized in that, in any one of claims 1 to 3, the precast concrete column is erected on a foundation with a curved structure, and a joint material is filled around the curved structure. The invention of claim 5 is characterized in that, in any one of claims 1 to 4, the precast concrete column is erected via a pedestal block, and a curved surface structure is formed on a lower surface of the pedestal block. Further, the invention of claim 6 is characterized in that, in claim 4 or 5, the curved structure comprises a sphere and a receiving seat into which the sphere is fitted. Further, the invention of claim 7 is characterized in that, in any one of claims 1 to 6, the PC steel material in the joint portion between the precast concrete column and the precast concrete beam is covered with an elastic sheath. Claim 8
According to a seventh aspect of the invention, the elastic sheath is made of synthetic resin or hard rubber. The invention of claim 9 is characterized in that, in any one of claims 1 to 8, a joint material is filled in a joint portion between the precast concrete column and the precast concrete beam. Further, the invention of claim 10 is characterized in that the joint material has the same strength as that of the precast concrete column, the precast concrete beam, the pedestal block and the foundation in claim 4 or 9 or is weaker than these. The invention of claim 11 is characterized in that, in any one of claims 1 to 10, the PC steel material is any one of a PC steel twisted wire, a PC steel rod, and a PC steel wire.

The PC steel material wired between the precast concrete beam and the precast concrete column was tensioned with an effective tension of 30 to 60% of the yield strength of the PC steel material, so that it can be used as a rigid prestressed concrete structure for medium earthquakes. For large earthquakes exceeding medium-sized earthquakes, it corresponds to a flexible joint elastic structure in which the precast concrete columns and precast concrete beams rotate around the joints. Never lose the integrity and property value of a prestressed concrete structure. Due to the curved structure, the precast concrete column or the precast concrete column with a pedestal block rotates around the joint. The elastic sheath in the joint deforms to absorb the seismic load, thereby preventing damage to the joint due to rotation of the precast concrete column and the precast concrete beam. The elastic sheath and concrete are unbonded. The precast concrete column, the precast concrete beam, the pedestal block and the foundation can be prevented from being damaged by the separation or partial damage of the joint material due to the rotation of the precast concrete column and the precast concrete beam. Prestressed concrete structures can be easily repaired by repairing minor joint damage.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the prestressed concrete structure (hereinafter referred to as PS structure) of the present invention will be described below.

FIG. 1 shows a PS structure 1 according to a first embodiment, which is a prestressed concrete column (hereinafter referred to as PS column) 2 to which a prestress is applied, and a precast concrete beam (to which a prestress is applied). Below PS
A beam 3 is erected and configured. The above prestress is applied by tensioning the PC steel material (primary cable) 4a arranged on the PS column 2 and the PS beam 3 with an effective tension of 80% of the yield strength of the PC steel material.

The PS column 2 is, as shown in FIGS. 2 and 3,
It is erected on a foundation 6 via a pedestal block 5, and is joined by a PC steel material (primary cable) 4 which is strained with an effective tension of 50% of the yield strength of the PC steel material. The pedestal block 5 is provided with a curved surface structure 7 for rotating the PS column 2,
This curved surface structure 7 is composed of a cast iron sphere 8 and a cast iron receiving seat 9, and a joint material 1 such as mortar is provided around them.
0 is filled. Further, the PC steel material 4 can also be tensioned with an effective tension force of 30 to 60% of the PC steel material yield strength. Therefore, if the effective tension is less than 30% of the PC steel yield strength, rigid joint cannot be made with the foundation 6, and if the effective tension exceeds 60% of the PC steel yield strength, the load of a large earthquake exceeding a medium earthquake Therefore, the PC steel material 4 may yield.
In this way, the PS column 2 has a foundation 6 and a PC steel yield strength of 5
By joining with an effective tension of 0%, it works as a rigid joint under a load of about a medium earthquake, and when it receives a load of a large earthquake that exceeds a medium earthquake, it rotates around the curved structure 7.

As shown in FIG. 4, the PS beam 3 has a joint end 11 installed on a beam receiving jaw 12 of a PS column through a joint material 10 such as mortar, and has a yield strength of 50% of PC steel.
PC steel materials (secondary cables in the upper and lower stages) 4 which are strained by the effective tension force of 4 are joined. The outer circumference of the PC steel material 4 is covered with a metal sheath 13, only the joint side is covered with an elastic sheath 14 of synthetic resin such as polyethylene resin, acrylic resin, epoxy resin or hard rubber, and the relationship between concrete 15 and unbonding. It has become. Further, the PC steel material 4 can also be tensioned with an effective tension force of 30 to 60% of the PC steel material yield strength. Therefore, if the effective tension force is less than 30% of the PC steel yield strength, rigid connection with the PS beam 3 cannot be made, and if the effective tension force exceeds 60% of the PC steel yield strength, the load of a large earthquake exceeding a medium earthquake will occur. By PC steel 4
May surrender. As described above, the PS beam 3 joined with the effective tension of 50% of the yield strength of the PC steel is in a state of being rigidly joined to the PS column 2 under a load of about a medium earthquake, but a large earthquake that exceeds a medium earthquake. When the load of 1 is received, as shown in FIG.

The PC steel material 4 is a PC steel stranded wire consisting of a core wire 16 and a side wire 17. As shown in FIG. 6, a coating layer 18 made of synthetic resin powder paint is provided on the outer circumference of the core wire 16 and the outer circumference of the side wire 17. Are adhered to each other, and the coating layer 18 and the sheaths 13, 14 are attached.
The rust preventive material 19 is filled between the and. The PC steel material 4 can be formed of PC steel wire or PC steel rod in addition to PC steel stranded wire.

Further, the joint material 1 in the above curved surface structure 7
By setting the strength of 0 and the strength of the joint material 10 at the joint between the PS column 2 and the PS beam 3 to be the same as or weaker than those of the PS column 2, the PS beam 3, the pedestal block 5, and the foundation 6. The joint material 10 is damaged by the rotation of the PS column 2 and the PS beam 3.

The PS structure 1 as described above corresponds to a rigid-joint rigid frame structure when a medium earthquake occurs, but when a large earthquake that exceeds the medium earthquake occurs, each joint rotates. It corresponds as a structure, that is, an elastic structure. In this way, the structure as a whole is elastically deformed against a large earthquake, and the joint material 10 at each joint is damaged, so that the damage of the PS structure 1 as a whole can be suppressed. This is to set the damaged portion of the PS structure 1 in the joint material 10 in advance, thereby simplifying the control of the damage degree and the repair, and maintaining its soundness and asset value.

In addition, in the PS structure 1, when a seismic isolation brace or seismic isolation damper is newly installed, the PS structure 1 is level 3 (60 to 7).
It is possible to cope with a huge earthquake (5 cm / sec) as a flexible joint elastic structure (not shown).

FIG. 7 shows the rotation performance of the joint between the PS column 2 and the PS beam 3 in the PS structure 1. 8 and 9 show the restoring force characteristics at the joint between the PS column 2 and the PS beam 3.
Even if the interlaminar deformation angle becomes a large deformation of 1/50, it exhibits non-linear elastic properties with little residual deformation, and the following effects as an elastic structure could be confirmed.

Further, in FIG. 10, the outer circumference is entirely covered with the metal sheath 1.
The PS structure 20 of 2nd Embodiment which joined the PS pillar 2 and the PS beam 3 with the PC steel material 4 coat | covered with 3 is shown, Other than this PS structure of 1st Embodiment. It has the same configuration as the object 1 and has the same effect.

By changing the effective tension of the PC steel material 4 wired between the PS column 2 and the PS beam 3 within the range of 30 to 60% of the PC steel yield strength according to the height of the PS structure 1. , Enhance the damping effect. This is, for example, to reduce the effective tension of the PC steel material 4 as the floor becomes higher.

[0018]

[Effect of the Invention] PC steel material wired to PS columns and PS beams is
By tensioning with an effective tension of 30 to 60% of the yield strength of PC steel, it can be used as a rigid-bonded PS structure for medium earthquakes and as an elastic structure for large earthquakes beyond a medium earthquake.

The soundness and property value of the PS structure are not lost.

Due to the curved structure, the PS column rotates around the joint with the foundation.

By deforming the elastic sheath and absorbing the seismic load, it is possible to prevent damage to the joint between the PS column and the PS beam due to rotation.

The elastic sheath and concrete can be unbonded.

Damage to the joint material due to the rotation of the PS column and PS beam can prevent damage to the PS column, PS beam, pedestal block and foundation.

By repairing minor damage to the joint material, P
The S structure can be easily repaired.

It is possible to preliminarily set the joint damage material at the time of a large earthquake.

The PS structure will be level 3 (60 to 75 cm / se if a seismic isolation brace or seismic isolation damper is newly installed.
It is possible to deal with the large earthquake of c) as a flexible joint elastic structure.

[Brief description of drawings]

FIG. 1 is an elevational view of a PS structure according to a first embodiment.

FIG. 2 is a sectional view of a joint portion between a PS column and a foundation.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a cross-sectional view of a joint between a PS column and a PS beam.

FIG. 5 is a conceptual diagram showing a rotating state of a PS beam.

FIG. 6 is a sectional view of a PC steel material.

FIG. 7 is a diagram showing rotation performance of a PS beam.

FIG. 8 is a diagram showing a restoring force characteristic of a PS beam.

FIG. 9 is a diagram showing a restoring force characteristic of a PS beam.

FIG. 10 PS in the PS structure of the second embodiment
In the cross-sectional view of the joint between the pillar and PS beam

[Explanation of symbols]

1,20 PS structure 2 PS pillar 3 PS beams 4 PC steel 5 pedestal block 6 foundation 7 curved structure 8 spheres 9 pedestal 10 joint materials 11 junction end 12 Beam receiving jaw 13 metal sheath 14 Elastic sheath 15 concrete 16 core wire 17 lateral lines 18 coating layer

Claims (11)

[Claims] 1. A precast concrete beam is erected between precast concrete columns erected on a foundation, and a joint end of the precast concrete beam is installed on a beam receiving jaw of the precast concrete column, and the precast concrete beam and the precast concrete beam are installed. PC steel material wired to the pillar is 30 to 60 of PC steel yield strength
% Prestressed concrete structure characterized by being tense with an effective tension. 2. A PC steel material wired between a foundation and a precast concrete column has a yield strength of 30 to 30%.
The prestressed concrete structure according to claim 1, wherein the prestressed concrete structure is tense with an effective tension of 60%. 3. The effective tension of the PC steel material wired between the precast concrete beam and the precast concrete column is changed according to the floor height.
Or the prestressed concrete structure according to 2. 4. The structure of prestressed concrete according to claim 1, wherein the precast concrete column is erected on the foundation with a curved structure, and a joint material is filled around the curved structure. object. 5. The prestressed concrete structure according to claim 1, wherein the precast concrete column is erected via a pedestal block, and a curved surface structure is formed on a lower surface of the pedestal block. . 6. The prestressed concrete structure according to claim 4, wherein the curved structure comprises a sphere and a receiving seat into which the sphere is fitted. 7. The prestressed concrete structure according to claim 1, wherein the PC steel material at the joint portion between the precast concrete column and the precast concrete beam is covered with an elastic sheath. 8. The prestressed concrete structure according to claim 7, wherein the elastic sheath is synthetic resin or hard rubber. 9. The prestressed concrete structure according to claim 1, wherein a joint material between the precast concrete column and the precast concrete beam is filled with a joint material. 10. The prestressed concrete structure according to claim 4, wherein the joint material has the same strength as the precast concrete column, the precast concrete beam, the pedestal block and the foundation or a strength lower than these. . 11. A PC steel material is a PC steel twisted wire, a PC steel rod,
It is any of PC steel wire, It is characterized by the above-mentioned.
10. The prestressed concrete structure according to any one of 10.