JPH10299263A - Construction of vibration isolation structure in existing building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely transmit the axial force of a column and reinforce a structure in its vibration-resistance, by fastening an existing column with additional concrete and transferring the axial force of the column to a support jack to transmit it to the lower part of the column and installing a vibration-isolation device to transfer the load. SOLUTION: An additional concrete 4 structure in which PC steel wires 3 for introducing prestresses are arranged, is constructed in the upper and lower parts of a column 1. Two semicylindrical bodies of the PC steel wires 3 are combined at a symmetrical arrangement of about 180 degrees of the outer periphery of the column 1. And both ends of the PC steel wires 3 are pulled to introduce a prestress horizontally and inward fastening the additional concrete 4 and transmit the axial force of the column 1 through the additional concrete 4. The PC steel wires 3 are processed with an unbonding treatment and the additional concrete 4 and the column 1 are fastened together by prestresses to integrally form them at necessary stages. A vibration- isolation device is installed in a hollow space of a cut column 1 and the upper and lower additional concrete 4 structures are connected to each other. In this way, the vibration-resistance of an existing building can be reinforced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting an existing building into a base-isolated structure, and more particularly to a method for forming a base-isolated structure using columns of an existing building.

[0002]

2. Description of the Related Art In recent years, as one of the seismic retrofitting techniques for buildings, a seismic isolation structure of an existing building has attracted attention, and various technological developments have been promoted. For example, the seismic isolation construction method for an existing building described in Japanese Patent Application Laid-Open No.
A support pile of an existing building is dug out, a temporary support is erected around the support pile, a jack is installed on the temporary support, the axial force of the support pile is changed to the temporary support by the jack, and then the support pile is replaced. The main contents of this project are dismantling, building a steel column to replace the supporting pile, installing a seismic isolation device between the steel column and the existing building, and then replacing the axial force of the temporary support with the steel column.

FIG. 6 shows an example of a seismic isolation method for mounting a seismic isolation device on a support pile. In this case, a retaining wall a is constructed on the ground on the outer periphery of the existing building, and the head of the support pile d is exposed by excavating the ground. After that, the same shaft pile (existing pile)
New foundation beam b and abandoned concrete c for fixing the head. Further, a temporary support pile e and a temporary support post f are formed on the outer periphery of the support pile d, and a foundation beam g for fixing the head of the temporary support post f is constructed. A new support beam k is also constructed. Then, a jack m is installed between the newly-installed temporary support post f and the support beam k, and the axial force of the existing support pile d is changed to the temporary support post f by the jack m. Cut off the part and seismic isolation device n
Attach. Then the seismic isolation device n
The main contents are the process of removing the jack m and the supporting pile d.

Japanese Patent Application Laid-Open No. 8-338104 discloses that the vertical strength of a new or existing concrete column is determined.
A method of strengthening by inward horizontal compressive stress (prestress) introduced by using PC steel is disclosed.

[0005]

The conventional seismic isolation method for an existing building has a common feature that a seismic isolation device is attached to a pile that supports the building. Therefore,
When implementing the seismic isolation structuring method, it is essential to excavate the ground until the piles are exposed. And
The construction of a retaining wall and the need for drainage treatment when the groundwater level is shallow require a very large and difficult operation. If the column bears a large axial force, it will require even reinforcement of the foundation beam, and the time and labor required for preparation will be enormous.

In order to convert an existing building into a seismic isolation structure, it is necessary to permanently reinforce a column to which the seismic isolation device is attached. As described in the above-mentioned Japanese Patent Application Laid-Open No. 8-338104,
Check the vertical strength of new or existing concrete columns by PC
The main method of strengthening with inward horizontal compressive stress, which is introduced using steel, is to reinforce it so that there is no fear of being destroyed by a large earthquake, and to use a seismic isolation structure to attach seismic isolation devices. It does not disclose ideas.

Accordingly, an object of the present invention is to provide a permanent reinforcement necessary for an existing column to which a seismic isolation device is to be attached, and to introduce a prestress that generates a horizontal inward tightening force in reinforced concrete added to the column. The existing building to increase the coefficient of friction between the existing columns and the additional concrete, and to transmit the axial force of the existing columns safely through the additional concrete, thereby making it easier to install seismic isolation devices. To provide a seismic isolation structuring method.

[0008]

According to a first aspect of the present invention, there is provided a method of structuring a seismic isolation of an existing building according to the present invention. Performing a roughening treatment on the surface of the skeleton, and arranging a PC steel wire for introducing prestress on the outer periphery of the upper and lower parts of the pillar excluding the mounting portion of the seismic isolation device, and performing concrete overstrike, After the strengthened concrete has developed a predetermined strength, a prestress is introduced in the circumferential direction using the PC steel wire to tighten the existing columns with the strengthened concrete, and a support is provided between the upper and lower end faces of the strengthened concrete. Installing a jack for the, the step of rearranging the axial force borne by the pillar to the support jack and transmitting it to the lower part of the pillar, and cutting off the mounting part of the seismic isolation device of the pillar,
Attach the seismic isolation device to the cut part, and then rearrange the load from the support jack so that the seismic isolation device bears the axial force borne by the column, and then the support jack is Loosening and removing.

According to a second aspect of the present invention, the additional concrete as set forth in the first aspect is provided on the outer peripheral portion thereof for about 180 hours.
It is characterized in that a pair or a plurality of pairs of jack mounting ribs are protruded in a symmetric arrangement. Claim 3
According to the invention described above, the unreinforced concrete PC steel wire according to claim 1 is subjected to an unbonding treatment and is formed into a semicircular shape. It is characterized in that it is formed in a circular arrangement.

According to a fourth aspect of the present invention, in the first aspect of the invention, the load is changed from the support jack so that the seismic isolation device bears the axial force borne by the column. The support jack is loosened and removed, and the prestress caused by the PC steel wire for the additional concrete is eliminated, but the additional concrete remains.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the load is changed from the support jack so that the seismic isolation device bears the axial force borne by the column. It is characterized in that the support jack is loosened and removed, and at the same time, the prestress by the PC steel wire for the additional concrete is eliminated, the additional concrete is removed, and then the outer periphery of the pillar is decorated.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The seismic isolation structuring method for an existing building according to the first aspect of the present invention is to attach a seismic isolation device to an existing building as shown in FIG. The roughening treatment 2 is performed on the surface of the body of the pillar 1 to be roughened. The roughening treatment 2 mentioned here is a means for maximizing the adhesion to the additional concrete to be cast later, and it is preferable to form irregularities having a large bearing effect. In some cases, a configuration in which a stud is protruded by an insert anchor is also preferable. FIG. 1b shows that the cross section of the column 1 is square.

Next, FIG. 2 shows a stage in which additional concrete 4 in which PC steel wires 3 for introducing prestress are arranged on the upper and lower peripheries of the column 1 excluding the mounting portion of the seismic isolation device is vertically arranged. Is shown. FIG. 2b shows that the PC steel wire 3 is formed in a semicircular shape (U-shape),
By forming two circles in a symmetrical arrangement of about 180 ° on the outer periphery of the steel wire and by equally pulling both ends of the PC steel wire 3 in a tangential direction indicated by an arrow, the additional concrete 4 is completely removed. This shows that a prestress for tightening the tag in a horizontal inward direction is introduced, as if the tag is tightened, and the two are integrated until the axial force borne by the column 1 can be transmitted by the increased concrete 1.

In order to facilitate the introduction of the prestress, the PC steel wire 3 has been subjected to an unbonding treatment. The prestress is introduced after the additional concrete 4 has developed a predetermined strength. FIG. 2A shows a configuration in which the PC steel wires 3 are respectively arranged in two stages in the up-down direction on the up-down concrete 4. However, the present invention is not limited to this example, and the PC steel wires are arranged in the number of steps necessary to integrate the additional concrete 4 and the column 1 by prestressing.

FIG. 2B shows a form in which a pair of jack mounting ribs 4a, 4a are projected on the outer peripheral portion of the additional concrete 4 in a symmetrical arrangement of about 180 °. However,
The number of the jack mounting ribs 4a is not limited to one pair, and two or more pairs may be provided in four orthogonal directions. FIGS. 3a and 3b show the supporting jacks 5 between the end faces of the up and down concrete 4 and 4, particularly the portions of the jack mounting ribs 4a and 4a which are relatively far from the pillar 1. FIG.
Are installed two by two, each supporting jack 5 is actuated, the axial force borne by the column 1 is changed from the additional concrete 4 to the supporting jack 5 and transmitted to the lower part of the column, Also, the mounting portion of the column 1 at which the seismic isolation device is attached is shown at the stage of being cut off. Of course, support jack 5
Is not limited to two by two, and an appropriate number is used in an appropriate arrangement for changing the axial force of the column 1. As is characteristic of FIG. 3a, the method of the present invention makes use of the temporary rearrangement of the vertical load bearing of the column 1 only on the assumption that the column 1 inherently has the bearing capacity. , It merely diverts the flow of power to the additional concrete 4
The other building structural elements (beams, etc.) do not bear any axial force. Therefore, unlike the conventional method, there is no need to reinforce the beams or the like of the building, and there is no need to separately prepare a borrowing column or the like that temporarily bears the axial force.

FIG. 4 shows a stage in which the seismic isolation device 6 is attached to the cavity of the pillar 1 that has been previously cut off, and is connected to the up and down concrete 4 with bolts 7. Further, FIG.
After the mounting, the support jack 5 is loosened, the load is changed so that the seismic isolation device 6 bears the axial force that the column 1 bears, and then the support jack 6 is removed. Is shown.

With the above, the work of mounting the seismic isolation device 6 on the column 1 is completed. After that, additional concrete 4
The prestress caused by the PC steel wire 3 working at the time is temporarily eliminated, but the additional concrete 4 is left as it is. This is a result of considering the convenience of maintenance such as replacement of the seismic isolation device 6 scheduled next. However, if the above considerations are not necessary, after eliminating the prestress by the PC steel wire 3 for the additional concrete 4, the additional concrete 4 is removed, and then the seismic isolation device 6 is attached to the outer periphery of the column 1. It is also feasible to apply a makeup to blindfold and make it easier to use existing buildings.

In any case, by attaching the seismic isolation device to all the pillars of the existing building by the above-mentioned method, the seismic isolation structure of the existing building is completed.

[0019]

[Effects of the present invention] The seismic isolation structuring method for an existing building according to the present invention is implemented for columns, so that work can be carried out by effectively utilizing the existing building space, and excavation of the ground can be performed. It is not necessary, and there is no need to consider the retaining wall and groundwater. And there is no need to prepare any temporary structures to temporarily receive the axial force of the columns other than the overcast concrete, and easily and quickly construct a seismic isolation structure in a short construction period without worrying about the structural strength of the beams or reinforcing them. Can be achieved.

[Brief description of the drawings]

FIG. 1A is an elevation view showing a stage where a pillar of an existing building is roughened, and FIG. 1B is a cross-sectional view taken along the line AA.

FIG. 2A is an elevation view showing a stage in which additional concrete is provided on a pillar of an existing building, and FIG. 2B is a cross-sectional view taken along the line BB.

FIG. 3A is an elevation view showing a stage in which a jack is installed between reinforced concrete and a part of a pillar of an existing building is cut off, FIG.
FIG. 3 is a sectional view taken along the line CC.

FIG. 4A is an elevation view showing a stage where a seismic isolation device is installed at a cut-off portion of a pillar of an existing building, and FIG. 4B is a cross-sectional view taken along the line DD.

FIG. 5A is an elevation view showing a stage in which a seismic isolation device has been attached to a cut portion of a pillar of an existing building, and FIG. 5B is a sectional view taken along the line EE.

FIG. 6 is a cross-sectional view illustrating a conventional seismic isolation structuring method.

[Explanation of symbols]

 1 pillar 2 roughening treatment 3 PC steel wire 4 reinforced concrete 5 support jack 6 seismic isolation device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Kimura 8-21-1, Ginza, Chuo-ku, Tokyo Inside Takenaka Corporation Tokyo Head Office (72) Inventor Katsuyuki Yoshida 8--21 Ginza, Chuo-ku, Tokyo 1 Inside Takenaka Corporation Tokyo Main Store (72) Inventor Akira Mizuno 8-21 Ginza, Chuo-ku, Tokyo Inside Tokyo Main Store (72) Inventor Haruhiko Okamoto Otsuka, Inzai City, Chiba Prefecture 1-5-1, Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Takahiro Moi 1-5-1, Otsuka, Inzai City, Chiba Prefecture, Japan Takenaka Corporation Technical Research Center

Claims (5)

[Claims] 1. A roughening treatment for a body surface of a pillar to which a seismic isolation device of an existing building is to be attached, and a prestress introduction for an upper part and a lower part of the pillar excluding a mounting part of the seismic isolation device. After arranging the PC steel wire and performing additional concrete, After the additional concrete has developed a predetermined strength,
Using the PC steel wire to introduce prestress in the circumferential direction and tightening the existing column with additional concrete, and installing a support jack between the upper and lower concrete ends, and the column bears Transmitting the axial force to the support jack and transmitting it to the lower part of the column, cutting off the mounting portion of the seismic isolation device of the column, attaching the seismic isolation device to the cut off portion, and then loading the column. Reloading the load from the support jack so that the seismic isolation device bears the axial force, and then loosening and removing the support jack. Seismic isolation structuring method. 2. The thickened concrete according to claim 1, wherein one or a plurality of pairs of jack mounting ribs are protrudingly provided on an outer peripheral portion thereof in a symmetric arrangement of about 180 °. Seismic isolation method for existing buildings. 3. The PC steel wire of the expanded concrete according to claim 1, which is subjected to an unbonding treatment and formed into a semicircular shape, and two of them are combined in an arrangement symmetrical about 180 ° around the outer periphery of the column. A seismic isolation method for an existing building, characterized in that it is formed in a circular arrangement. 4. The load is changed from the supporting jack so that the seismic isolation device bears the axial force that the column bears,
2. The seismic isolation structure of an existing building according to claim 1, wherein the support jack is loosened and removed after that, and the prestressed by the PC steel wire for the reinforced concrete is eliminated, but the reinforced concrete remains. Method. 5. The rearrangement of the load from the support jack is performed so that the seismic isolation device bears the axial force that the column bears,
After that, the support jack is loosened and removed, and the prestressing of the additional concrete by the PC steel wire is eliminated, the additional concrete is removed, and thereafter, the outer periphery of the pillar is subjected to makeup. The seismic isolation structuring method of the existing building described in 1.