JP2004044197A - Vibration control structure for concrete structure made of fiber reinforced cement material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control structure for controlling the response to an earthquake of a concrete structure using fiber reinforced cement material. <P>SOLUTION: In a concrete Rahmen structure, a range 3 where formation of a plastic hinge at the end of a beam member 2 is supposed is formed by a fiber reinforced cement material. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a concrete-based ramen structure assuming a total collapse, by forming a range in which a plastic hinge at an end of a beam member is assumed to be formed with a fiber-reinforced cement-based material, thereby reducing an earthquake response of the structure. It belongs to the technical field of seismic control structure of concrete structure made of fiber reinforced cement based material which can be controlled.
[0002]
[Prior art]
Conventionally, in a concrete ramen structure as illustrated in FIG. 10, energy input to the structure during a large earthquake is, as illustrated in FIG. 11, column bases a on the first floor and beam ends on each floor. The design and construction are performed so as to be absorbed by a plastic hinge (a pin-shaped hinge formed by yielding a cross section of the member due to a load) formed in b. For this reason, in a portion where the formation of a plastic hinge is assumed, brittle fracture is prevented, and shear reinforcing bars and stirrups are densely arranged for the purpose of providing sufficient strength and rotational deformation capability.
[0003]
However, in the case of ordinary reinforced concrete construction, even if reinforcing bars are densely arranged, the dispersibility of cracks is limited, and it is extremely difficult to control damage at a plastic hinge portion where cracks are particularly concentrated.
[0004]
Also, measures are taken to arrange Y-shaped braces c as shown in FIG. 12 and to arrange studs d as shown in FIG. However, since these damping devices are incorporated between the upper and lower beam members, it is a troublesome solution that both the floor plan to secure entrances and passages and the layout plan of braces and studs must be compatible. Exists. In the case of the studs d, it is also a problem that a large number of studs need to be arranged in order to expect a damping effect in a normal building.
[0005]
As a different prior art, the vibration control structure of a reinforced concrete building described in Japanese Patent Application Laid-Open No. 11-22240 discloses a structure in which a gap is provided between both left and right side edges of a shear-resistant wall and a column, and furthermore, the height of the A gap is formed in the hanging wall and the waist wall by dividing the intermediate portion into upper and lower portions, and a damper made of a fiber-reinforced cement material is arranged in the gap to fasten the upper and lower hanging wall and the waist wall. .
[0006]
Next, in the construction method of reinforced concrete columns described in Japanese Patent Publication No. 6-99955, the upper end position of the columns is formed of ordinary concrete, and the lap joints between the main bars of the columns are made of fiber reinforced cement material. A technique for forming is disclosed.
[0007]
Further, the beam-column connection structure described in Japanese Patent Application Laid-Open No. 10-8551 discloses a technique in which the beam-column connection is formed of fiber-reinforced concrete (fiber-reinforced cement-based material).
[0008]
[Problems to be solved by the present invention]
It is known that in a normal reinforced concrete frame structure, when a large repeated load is applied during a large earthquake, plastic rotational deformation is concentrated at the beam end. As shown in exaggeration in FIG. 9, this plastic rotational deformation is caused by bending deformation and bending cracks at the ends of beam members, crushing of concrete, and deterioration of adhesion due to shear deformation and repeated loads near dangerous cross sections of beams. This is due to the pull-out of the tensile-side steel material (beam main bar) resulting from the above. If the amount of reinforcing bars is small, the proof stress rapidly decreases, so that the plastic deformation rotation capability is small and large energy absorption capability cannot be expected. In addition, even if the structure can be used only by simple repair after the earthquake, it is a problem to give an impression that the apparent damage is severe.
[0009]
As an improvement measure relating to such plastic rotation deformation of the beam end, the invention relating to the vibration control structure of a reinforced concrete building described in the above-mentioned Japanese Patent Application Laid-Open No. 11-22240, and Japanese Patent Publication No. 6-99955 is described. The invention relating to the method of constructing a reinforced concrete column and the invention relating to the beam-column connection structure described in JP-A-10-8551 have different technical ideas and are powerless.
[0010]
Next, a so-called fiber-reinforced cementitious material (or fiber-reinforced mortar) in which short fibers such as carbon fiber, aramid fiber, glass fiber, vinylon fiber, polypropylene fiber, and steel fiber are mixed as a reinforcing material for concrete is used in conventional ordinary concrete. Compared with, it is known that the cracks at the time of tension are dispersed, and that the fibers have an effect of restraining the width of the cracks from opening, thereby exhibiting excellent apparent tensile strength and tensile toughness. As already explained in the section of the prior art, it is already used as a part of a concrete structure.
[0011]
Therefore, when forming at least the range in which the formation of the plastic hinge is assumed at the beam end of the concrete frame structure by the fiber-reinforced cementitious material, bending cracks and shear cracks of the plastic hinge portion are dispersed, and the fiber The opening of the crack is restrained from opening, so that so-called peeling of the concrete does not occur, and a sharp decrease in the proof stress does not occur. Further, the bonding strength between the reinforcing steel and the concrete is improved, and eventually, the plastic deformation rotation ability is increased. Therefore, a larger energy absorbing ability can be expected. Therefore, the present invention has been made focusing on the fact that the seismic response of the whole building can be controlled by appropriately grasping and designing the energy absorption amount.
[0012]
Another problem to be solved is that fiber-reinforced cementitious materials are difficult to cast in place due to their properties.
[0013]
Therefore, an object of the present invention is to form the `` at least a range in which the formation of a plastic hinge is assumed '' at the beam end of a concrete frame structure assuming total collapse by the fiber-reinforced cement material, Vibration control that increases the plastic deformation rotation capacity, enables seismic response control of the entire building, and eliminates the need for installation of vibration control devices that affect the floor plan of openings, etc., and adds a vibration control effect to structures. Is to provide a structure.
[0014]
The next object of the present invention is to form a range in which the formation of a plastic hinge is assumed by the fiber-reinforced cementitious material, thereby increasing the deformation capacity while reducing the amount of shear reinforcement in the assumed portion of the plastic hinge, By providing a large seismic energy absorption capacity as a whole, with excellent crack dispersibility, reducing the degree of damage, and providing a seismic control structure that can be reused with only simple repairs after an earthquake. is there.
[0015]
[Means for Solving the Problems]
As means for solving the above-mentioned problems of the prior art, as a means for damping a concrete structure using a fiber-reinforced cement material according to the invention of claim 1,
In concrete ramen structures,
The range in which the formation of the plastic hinge at the end of the beam member is assumed is made of a fiber-reinforced cement-based material.
[0016]
According to a second aspect of the present invention, there is provided a vibration control structure for a concrete structure using the fiber reinforced cement material according to the first aspect,
The range in which the plastic hinges at both ends of the beam member are assumed to be formed is formed of a fiber-reinforced cementitious material, and the beam is constructed of a precast beam member whose intermediate portion is formed of ordinary concrete.
[0017]
According to a third aspect of the present invention, there is provided a vibration control structure for a concrete structure using the fiber-reinforced cement material according to the first aspect,
A range in which the plastic hinges at both ends of the beam member are assumed to be formed is formed of a fiber-reinforced cementitious material, and the intermediate portion is a series of U-shaped cross-sections of the same fiber-reinforced cementitious material which also serve as a beam form. A beam is framed by the beam member, and ordinary concrete is cast into a U-shaped cross-section that also serves as the beam formwork.
[0018]
According to a fourth aspect of the present invention, there is provided a vibration control structure for a concrete structure using the fiber-reinforced cementitious material according to the first aspect,
The range in which the formation of the plastic hinge at the end of the beam member is assumed is formed as a beam block made of fiber-reinforced cementitious material, and the beam block is installed at the beam position of the column. It is characterized by being constructed integrally with the beam block by ordinary concrete using a frame.
[0019]
According to a fifth aspect of the present invention, there is provided a vibration control structure for a concrete structure using the fiber-reinforced cement material according to the first aspect,
In the column-beam joint block made of ordinary concrete as the beam joint part of the column, the range where the formation of the plastic hinge at the end of the beam member is assumed to be integrally formed as a beam block made of fiber reinforced cement material The column-beam joint block is installed on the column united with the beam block, and the intermediate portion of the beam member is integrally formed integrally with the beam block by ordinary concrete using a beam formwork. It is characterized by.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a vibration damping structure of a concrete structure using a fiber reinforced cement material according to the first to fifth aspects of the present invention will be described with reference to the embodiments shown in FIGS.
[0021]
First, FIG. 1 shows that in a concrete frame structure in which the column 1 and the beam 2 are made of reinforced concrete, the “range 3 where the formation of a plastic hinge is assumed” at the end of the beam member 2 is formed of a fiber-reinforced cement-based material. An embodiment of the damping structure is conceptually simplified and shown (the invention according to claim 1). The definition, content and properties of the fiber-reinforced cementitious material are as described in the above paragraph [0010].
[0022]
FIG. 2 shows a more specific embodiment of the vibration damping structure of a concrete structure using the fiber reinforced cement material shown in FIG. That is, a range 3 in which the formation of plastic hinges at both ends of the beam member 2 is assumed is formed of a fiber-reinforced cementitious material, and a precast beam member whose intermediate portion 4 is formed of ordinary concrete is manufactured in advance at a factory. Is carried into the site, and a beam is constructed between the columns 1 and 1 by a known method (the invention according to claim 2). This is because fiber-reinforced cementitious materials are difficult to cast in place due to their properties.
[0023]
The illustrated beam member 2 is configured as a well-known half precast beam member that exposes a part of the beam main reinforcement 5 and the hoop reinforcement 6 on the upper surface thereof and facilitates the integrated construction with the slab concrete to be subsequently cast. Are shown.
[0024]
Next, in the embodiment of FIG. 3, as in FIG. 2, the range 3 where the formation of the plastic hinges at both ends of the beam member 2 is assumed is formed of the fiber-reinforced cementitious material, but the intermediate portion 4 is As shown in FIG. 3C, a U-shaped cross section also serving as a beam form is formed of a fiber-reinforced cementitious material in series (integrally). Then, it is manufactured in a factory in advance as a precast beam member having a configuration in which a beam reinforcing bar composed of the beam main reinforcing bar 5 and the hoop bar 6 is accommodated in the above-described groove, and the precast beam member is transported to the site, and a known space is inserted between the columns 1 and 1. The beam is constructed by the method.
[0025]
The intermediate portion 4 is also implemented in a configuration in which the lower half of the beam reinforcement is embedded in a fiber-reinforced cementitious material, as in the example shown in FIG. 3D.
[0026]
In any case, the beam member 2 of the present embodiment, after being erected between the columns 1 and 1, when casting the slab concrete, the ordinary concrete is made of a U-shaped cross-section part also serving as the beam formwork of the intermediate part 4. The beam is completed by being cast in the groove (the above is the invention according to claim 3).
[0027]
According to the embodiment of the present invention, since the intermediate portion 4 is notched and formed as a U-shaped cross section that also serves as a beam form and is carried into the site, the weight of the beam member is significantly reduced as compared with the embodiment of FIG. Therefore, there is an advantage that costs can be reduced because labor for transportation and installation can be reduced.
[0028]
Next, in the case of the embodiment shown in FIG. 4, the range in which the formation of the plastic hinge at the end of the beam member is assumed is independently formed as a beam block 30 made of a fiber-reinforced cementitious material. It is installed at one beam mounting position. However, the illustration of the means (support) for supporting the beam block 30 is omitted. As shown in FIG. 4B, the beam block 30 has a sheath hole 7...
[0029]
Further, FIG. 5 shows that, after the main reinforcements 5 are passed through the sheath holes 7 of the beam block 30 installed at the beam mounting position of the column 1 as shown in FIG. Other beam reinforcing bars 5, 6 and slab bars are installed, and a panel zone is integrated with slab concrete by concrete casting on site, and at the same time, an intermediate portion of the beam member 2 is also integrally formed with the beam block 30 by ordinary concrete. This shows a method of integrally constructing the above (the invention according to claim 4). Reference numeral 8 in FIGS. 4 and 5 indicates a reinforcing bar for a pillar.
[0030]
FIG. 6 shows a beam block 30 made of the fiber-reinforced cementitious material, in which the PC steel material 9 passed through the sheath hole is also arranged so as to penetrate the column 1, and is press-bonded to the beam position of the column 1 by a known method to be integrated. 5 shows an embodiment in which an intermediate portion of the beam member 2 is integrally formed with the beam block 30 by ordinary cast-in-place concrete, as in the example of FIG.
[0031]
Next, FIG. 7 shows a range in which a plastic hinge at the end of the beam member 2 is assumed to be formed in a beam-to-column joint block 10 made of ordinary concrete as a beam-joint portion of the column 1 using a fiber-reinforced cement-based material. This shows how to integrally form the block 30 as a precast concrete member in a factory in advance, carry it into the site, and install it on the pillar 1. The column-beam joining block 10 is provided with sheath holes 10a through which the main bars 8a of the columns 1 pass, in the vertical direction. In the beam block 30, a main reinforcing bar 5 constituting a beam reinforcing bar is arranged so as to penetrate the column-beam connecting block 10, and further a hoop reinforcing bar 6 is arranged. It is configured as a half precast member whose part is exposed.
[0032]
FIG. 8 shows an embodiment in which the beam-column joint block 10 having the above-described configuration is installed together with the beam block 30 on the upper portion of the column 1 (beam mounting position) in such a manner that the main reinforcement 8a of the column 1 passes through the sheath hole 10a. The form is shown. Thereafter, although not shown, the intermediate portion of the beam member 2 is integrally and continuously constructed with the beam block by ordinary concrete using a beam formwork (the invention according to claim 5).
[0033]
[Effects of the present invention]
In the vibration damping structure of a concrete structure using the fiber-reinforced cement material according to the first to fifth aspects of the present invention, the range in which the formation of the plastic hinge at the end of the beam member is assumed to be formed by the fiber-reinforced cement material. Therefore, bending cracks and shear cracks in the above range are dispersed, the bonding strength between the reinforcing steel and the concrete is high, and the plastic rotational deformation performance is increased. By properly grasping and designing the performance, it is possible to provide a vibration control structure that controls the earthquake response of the entire concrete structure.
[0034]
Moreover, it is not necessary to use a damping device such as another expensive damper, and the damping performance can be imparted to the concrete structure. Therefore, it can be implemented at low cost and without any influence on the floor plan of the building.
[0035]
In the range in which the plastic hinge at the end of the beam is assumed to be formed, dense rebars necessary for imparting sufficient plastic rotational deformation performance are unnecessary, so that the workability is greatly improved.
[0036]
Moreover, the fiber-reinforced cementitious material has an effect of dispersing cracks, and since damage is hardly concentrated at one place, visual damage is also reduced, which is advantageous for reuse after an earthquake.
[0037]
Furthermore, as a result of promoting the precasting of the structure, it also contributes to labor saving and quality improvement of on-site work.
[Brief description of the drawings]
FIG. 1 is an elevation view showing a basic embodiment of a vibration control structure for a concrete structure according to the present invention.
2A is a front view showing a structure of a beam member, and FIGS. 2B and 2C are cross-sectional views taken along line bb and cc of FIG.
3A is a front view showing a different structure of a beam member, and FIGS. 3B, 3C, and 3D are cross-sectional views taken along line bb and cc of FIG.
FIG. 4A is an elevational view showing a state where a beam block is installed on a pillar, and FIG. 4B is a sectional view taken along line bb of FIG.
FIG. 5 is an elevation view showing an example of construction of a beam member by the beam block.
6A is an elevation view showing an example of building a beam member by the beam block, and FIG. 6B is a sectional view taken along line bb of FIG.
FIG. 7A is an elevation view showing a procedure for installing a beam-column joint block and a beam block together on a column.
FIG. 8 is an elevation view showing an example of building a beam member by the beam block.
FIG. 9 is an explanatory diagram of plastic rotational deformation performance of a beam end.
FIG. 10 is an elevation view showing a general example of a concrete structure.
FIG. 11 is an explanatory diagram showing a state of generation of a plastic hinge due to seismic energy.
FIG. 12 is an elevation view showing an example in which a Y-type brace is installed on a concrete structure.
FIG. 13 is an elevation view showing an example in which studs are installed on a concrete structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Column 2 Beam member 3 Range in which plastic hinge is formed 4 Intermediate part of beam 30 Beam block 10 Beam-column joint block

Claims (5)

In concrete ramen structures,
A vibration damping structure for a concrete structure made of a fiber reinforced cement material, wherein a range in which a plastic hinge at an end of a beam member is assumed is formed of a fiber reinforced cement material. The range in which the formation of the plastic hinges at both ends of the beam member is assumed is formed by a fiber-reinforced cementitious material, and the beam is constructed by a precast beam member formed of ordinary concrete at an intermediate portion. A vibration control structure for a concrete structure using the fiber-reinforced cement material according to claim 1. A range in which the plastic hinges at both ends of the beam member are assumed to be formed is formed of a fiber-reinforced cement-based material, and the intermediate portion is a series of U-shaped cross-sections of the same fiber-reinforced cement-based material that also serve as a beam form. 2. The concrete structure according to claim 1, wherein a beam is framed by a beam member, and ordinary concrete is poured into a U-shaped cross section serving also as the beam formwork. Damping structure. The range in which the formation of the plastic hinge at the end of the beam member is assumed is formed as a beam block made of fiber-reinforced cementitious material, and the beam block is installed at the beam position of the column. The vibration control structure for a concrete structure made of a fiber-reinforced cementitious material according to claim 1, characterized in that the concrete structure is constructed integrally with the beam block by a normal concrete using a frame. In the beam-column joint block made of ordinary concrete as the beam joint part of the column, the range where the formation of the plastic hinge at the end of the beam member is assumed is integrally formed as a beam block made of fiber reinforced cement material. The beam-to-column joint block is installed on the column unitedly with the beam block, and furthermore, the intermediate portion of the beam member is integrally formed integrally with the beam block by ordinary concrete using a beam formwork. A vibration damping structure for a concrete structure using the fiber-reinforced cementitious material according to claim 1.

Images