JP2007277856A - Aseismatic reinforcing structure of existing building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aseismatic reinforcing structure of an existing building capable of avoiding the extension of a foundation, by minimizing a vertical load generated in reinforcing columns of an aseismatic reinforcing frame. <P>SOLUTION: The aseismatic reinforcing frame 5 is arranged along an outside surface of the existing building 1 having a plurality of stories, and has a plurality of reinforcing columns 6a and 6b running along a column 2 of the existing building, a plurality of reinforcing beams 7 running along a beam 3 of the existing building, and a horizontal resistance element 8 arranged in a structural plane composed of these reinforcing columns and reinforcing beams; and is characterized in that in the other reinforcing column 6b except for the reinforcing columns 6a positioned in both side end parts, the total axial force in the respective reinforcing columns 6b of adding vertical directional additional axial force transmitted from the horizontal resistance element 8 positioned on the right and left of the reinforcing column 6b in an earthquake, to axial force by weight of the aseismatic reinforcing frame 5 acting on the respective reinforcing columns 6b, is set within an allowance degree of support capacity in an existing foundation part to which the total axial force is transmitted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seismic reinforcement structure that improves seismic performance in an existing building by arranging a seismic reinforcement frame along the outer surface of the existing building.

With the previous Hyogoken-Nanbu Earthquake, etc. as an opportunity, the existing buildings such as buildings designed in accordance with the old Building Standards Law and buildings that are concerned about aging are reinforced to provide earthquake resistance. Various seismic reinforcement structures have been developed to improve the performance.
As one type of such seismic reinforcement structure, rigidity and strength can be improved by adding steel braces and reinforced concrete walls in the column beam structure of existing buildings, or by increasing the number of existing walls. Those that improve both are known.

By the way, in the conventional seismic reinforcement structure, since there are new restrictions on the use of the interior of the building after reinforcement, and the construction is entirely inside the existing building, the interior of the building cannot be used during the renovation period. There is a drawback.
Therefore, in particular, when there is a request to install seismic reinforcement for the existing building while using the inside of the existing building, a seismic reinforcement frame is installed along the outer periphery of the existing building. The method of integrating the column beam frame is adopted.

  For example, in the following Patent Document 1, it is composed of a reinforcing column extending in the vertical direction, a reinforcing beam extending in the horizontal direction, and a reinforcing brace laid between the reinforcing column and the reinforcing beam, and A steel frame reinforcement frame in which the reinforcing braces are arranged in a staggered manner adjacent to each other in an oblique direction so as to reduce the difference in the axial force load between the side edge and the center of the building is arranged on the outer surface of the building. Reinforcement structure of the building has been proposed.

And, according to the reinforcing structure of the building, when a large horizontal external force due to an earthquake or the like is applied, it is possible to reduce the difference in the axial force burden between the side end portion and the center portion of the building as compared with the conventional case. In particular, because it is possible to reduce the strength waste in the center, it is said that the reinforcement frame made of steel frame or reinforced concrete can efficiently bear horizontal external force and improve the earthquake resistance of the building. ing.
JP-A-10-18639

  By the way, when such a seismic strengthening frame is installed, in addition to the vertical load due to its own weight, if a large horizontal force acts on the seismic strengthening frame during an earthquake, it acts from horizontal resistance elements such as braces. A large vertical load acts on the reinforcing column due to the component force. Therefore, when the seismic retrofit frame is integrated with an existing building, the vertical load transmitted from the reinforcing column to the existing building exceeds the margin of the support capacity in the foundation of the existing building. It is necessary to reinforce the foundation of the building, or to add a foundation to support the vertical load acting from the reinforcing column at the bottom of the seismic reinforcement frame.

As a result, there has been a problem that the seismic reinforcement work becomes large-scale, which requires a lot of work and construction time, and increases the construction cost.
In particular, in the above-described conventional building reinforcement structure, the reinforcement brace is arranged so that the difference in the axial load between the side end portion and the center portion of the building is reduced. In order to support the vertical load, it may be necessary to provide a new foundation over the entire reinforcing frame in order to support the vertical load depending on the margin of the support capacity of the foundation of the existing building. There was a problem.

  The present invention has been made in view of such circumstances, and in the case where the horizontal strength of an existing building is increased by adding a seismic reinforcing frame, the weight of the seismic reinforcing frame and the vertical load of the reinforcing column acting from the horizontal resistance element are minimized. It is an object of the present invention to provide a seismic reinforcement structure for an existing building that can minimize the number of additional foundations by setting it small.

  In order to solve the above-mentioned problem, the invention according to claim 1 is provided with an earthquake-resistant reinforcement structure in which an earthquake-proof reinforcement frame is disposed along the outer surface of an existing building having a plurality of levels and is connected to the column beam frame of the existing building. The seismic reinforcement frame includes a plurality of reinforcing columns arranged along the columns of the existing building, a plurality of reinforcing beams arranged along the beams of the existing building, and these reinforcing columns and A horizontal resistance element provided in a structural surface constituted by reinforcing beams, and acting on each of the reinforcing columns in the other reinforcing columns excluding the reinforcing columns located at both ends. The total axial force in each of the reinforcing columns is the axial force due to the weight of the seismic reinforcing frame added to the vertical additional axial force transmitted from the horizontal resistance element located on the left and right of the reinforcing column in the event of an earthquake. In the existing foundation where the total axial force is transmitted It is characterized in that is within the margin of the support capability.

  The invention according to claim 2 is the invention according to claim 1, wherein the existing building is constructed of a column beam frame having the same beam span and the same floor height, and the seismic strengthening frame has the horizontal resistance. The elements are arranged such that the proof stresses of the elements are substantially equal to each other on the left and right of each of the reinforcing columns.

  On the other hand, the invention according to claim 3 is the invention according to claim 1, wherein the existing building is constructed by a column beam structure having a beam span and / or a different floor height at least partially, and In the reinforcing frame, the magnitude relationship of the proof stress of the horizontal resistance element on the left and right of each reinforcing column is opposite to the aspect ratio of the aspect ratio obtained by dividing the floor height of the place where the horizontal resistance element is installed by its span. It is characterized by being arranged.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the seismic reinforcement frame is provided between the reinforcement column on the lowest floor and the existing building. A transmission reinforcing member for transmitting a vertical force acting on the foundation to the foundation of the existing building is interposed.

Furthermore, the invention according to claim 5 is characterized in that the transmission reinforcing member according to claim 4 is integrated with the lowermost part of the reinforcing column and the column of the existing building through a joining means. The reinforcing wall is arranged in a direction orthogonal to the reinforcing frame.
Here, as the joining means, a post-construction anchor, a steel through-bolt, or a tightening force due to its introduction force can be applied.

  The invention according to claim 6 is the brace according to any one of claims 1 to 5, wherein the horizontal resistance element is interposed in a diagonal direction of the construction surface. And in the front view, the seismic strengthening frame is arranged from the upper right corner of the construction surface toward the lower left corner with the reinforcing column in the center as a boundary, and the brace located on the left side of the structural surface. The brace located on the right side is arranged from the upper left corner of the construction surface toward the lower right corner.

  According to the invention according to any one of claims 1 to 6, the total axial force acting on the existing building from each of the other reinforcing columns excluding the reinforcing columns at both ends by installing the seismic reinforcing frame, In other words, the axial force due to the weight of the seismic reinforcement frame acting on each reinforcing column is combined with the vertical additional axial force transmitted to the reinforcing column from the horizontal resistance element located on the left and right of each reinforcing column in the event of an earthquake. The total axial force is set within the margin of the support capacity in the foundation part of the existing building to which the axial force of each reinforcing column is transmitted.

  For this reason, when installing a seismic retrofit frame, at least excluding the reinforcement columns at the ends of both sides, constructing a new foundation to support other reinforcement columns, and existing buildings where the axial force of the reinforcement columns is transmitted Measures to increase the support capacity of the foundation of the foundation, such as increasing the ground strength by improving the ground directly below or around the foundation, or additional piles or foundations that are integrated with the foundation by hitting a new pile around the foundation There is no need to perform additional construction to reinforce various foundation parts, such as additional foundations that increase the support area of the foundation, and therefore, simple construction without any significant restrictions on the use of existing buildings Seismic reinforcement can be performed.

Here, in particular, in order to suppress the sum of the axial forces in the vertical direction transmitted from the horizontal resistance elements located on the left and right of each of the reinforcing pillars to the reinforcing pillars at the time of an earthquake, the horizontal resistance elements are It is preferable to arrange the reinforcing columns so that their proof stresses are antagonistic on the left and right sides.
For example, when the existing building has the same beam span and floor height over a plurality of floors, the proof strength of the horizontal resistance element of the seismic reinforcement frame is set to the left and right of each reinforcing column as in the invention described in claim 2. If they are arranged so as to be equal to each other, the additional axial force can be easily set within the margin of the support capability in the foundation of the existing building.

That is, as shown in FIG. 5, the reinforcing column A is arranged along the columns of the existing building, the reinforcing beam B is arranged along the beam of the existing building, and the reinforcing columns A and the reinforcing beams B. When a large horizontal force F is applied during an earthquake in a seismic strengthening frame provided with braces (horizontal resistance elements) C ₁ and C ₂ provided in the structural surface, the brace C ₁ on the left side of the reinforcing column A is applied. As a result, a compressive force f ₁ acts and a tensile force f ₂ acts by the brace C ₂ on the right side thereof.

As a result, for example, assuming that the proof strengths of the braces C ₁ and C ₂ are equal, the sum of the axial forces in the vertical direction transmitted from the braces C ₁ and C _{2 on} the left and right sides of the reinforcing column A to the reinforcing column A (f ₁ -f ₂₎ is substantially zero (zero).
Therefore, when the existing building has a plurality of floors, the total resistance of horizontal resistance elements arranged in the vertical direction on the left side of the reinforcing column and the horizontal resistance elements arranged in the vertical direction on the right side of the reinforcing column By arranging them so that their total proof stresses are equal to each other, the sum of the axial forces in the vertical direction acting on the reinforcing columns during an earthquake can be easily made substantially zero.

On the other hand, as shown in FIG. 6, the existing building is a column beam in which spans S ₁ and S ₂ and / or floor heights H ₁ and H ₂ of the reinforcement beam B between the reinforcement columns A are different at least partially. When constructed by a frame, as in the invention described in claim 3, the magnitude relationship between the proof strengths of the braces (horizontal resistance elements) C ₁ and C _{2 on} the left and right of each reinforcing column A is represented by these braces C. ₁ , so that the floor height H ₁ , H ₂ of the place where C ₂ is installed is opposite to the magnitude relationship of the aspect ratio (H ₁ / S ₁ , H ₂ / S ₂ ) divided by the spans S ₁ and S ₂ By setting to, the same effect can be obtained.

  Further, according to the present invention, a new foundation for supporting these vertical loads is unnecessary for the other reinforcing columns excluding at least the reinforcing columns at both ends. As described above, it is preferable that a transmission reinforcing member is interposed at least between the reinforcing column on the lowest floor and the existing building so that the vertical load of these reinforcing columns is directly transmitted to the foundation of the existing building.

  At this time, as in the invention described in claim 5, as the transmission reinforcing member, post-installed anchors and the like are arranged in the direction perpendicular to the earthquake-proof reinforcing frame and the lowermost part of the reinforcing column and the column of the existing building. For example, there is a difference in the proof stress of the horizontal resistance elements located on the left and right, resulting in a larger vertical axis during an earthquake than other reinforcing columns. It is suitable for integrating a reinforcing column on which a force acts with a column of an existing building.

  In addition, when the existing building has a structure that protrudes from the wall surface such as a balcony, it is necessary to dispose the seismic reinforcement frame on the outer surface side of the structure. By using, it becomes possible to reliably transmit the load acting from the earthquake-proof reinforcement frame to the foundation of the existing building.

  Furthermore, as the horizontal resistance element, it is possible to use a brace provided in a V-shape or an X-shape in a structural surface constituted by a reinforcing column and a reinforcing beam. As described in the invention, if one brace interposed in the diagonal direction of the structural surface is used, it is possible to minimize the sunshine obstacle to the existing building caused by the installation of the earthquake-proof reinforcement frame.

  The one brace is arranged from the upper right corner of the composition surface to the lower left corner on the left side with the central reinforcing column as a boundary, and from the upper left corner portion of the composition surface on the right side. If it arrange | positions toward a lower right corner, the said brace will draw a mountain shape as a whole, and the effect that the design property improves will also be acquired.

(Embodiment 1)
1 and 2 show a first embodiment of the seismic reinforcement structure for an existing building according to the present invention, and reference numeral 1 in the figure is an existing building having a plurality of layers (fourth floor in the figure).
The existing building 1 is constructed of a plurality of (11 in the figure) pillars 2 and beams 3 installed between the pillars 2, and each floor has a balcony protruding from the front wall surface. 4 is provided. In addition, 1a in the figure is a window formed on the front wall surface.

And along the front wall of the balcony 4 of this existing building 1, the steel structure earthquake-proof reinforcement frame 5 for earthquake-proofing the existing building 1 is arrange | positioned.
The seismic reinforcement frame 5 is arranged along a plurality of reinforcing columns 6a and 6b (9 in total in the present embodiment) arranged along the pillar 2 of the existing building 1 and the beam 3 of the existing building 1. Having a plurality of reinforcing beams 7 (five in the figure), and one brace (horizontal resistance element) 8 provided in a structural surface constituted by the reinforcing columns 6 and the reinforcing beams 7. It is.

Here, in this seismic reinforcement frame 5, the braces 8 are arranged so that two of them are positioned on the left and right sides of the other reinforcing columns 6b excluding the reinforcing columns 6a at both ends.
Accordingly, as in the case shown in FIG. 5, each reinforcing column is utilized by utilizing that the sum of the axial forces in the vertical direction transmitted from the left and right braces 8 to the reinforcing columns 6b is substantially zero. In addition to the total axial force acting on 6b, that is, the axial force due to the weight of the seismic reinforcement frame 5, an additional axial force in the vertical direction transmitted from the braces 8 positioned on the left and right of each reinforcing column 6b to the reinforcing column 6b during an earthquake is added. The axial force is set so as to be within the margin of the support capacity of the foundation 12 of the existing building 1.

  Further, these braces 8 are arranged in such a manner that the brace 8 located on the left side of the central reinforcing column 6b is arranged from the upper right corner portion to the lower left corner portion of the above-mentioned composition surface in front view. The brace 8 located on the right side is arranged from the upper left corner of the construction surface toward the lower right corner.

  On the other hand, as shown in FIG. 2, a new slab (transmission reinforcing member) 9 is added on the lower surface of the slab of the balcony 4 on the predetermined floor. This new slab 9 is used to transmit the horizontal force acting on the seismic reinforcement frame 5 to the pillar 2 and the beam 3 of the existing building 1 in the event of an earthquake, and is provided at the post-installed anchor for shearing and at both end portions thereof. It is integrated with the beam 3 and the column 2 via a post-tensioning anchor for eccentric bending.

And each seismic reinforcement frame 5 is connected to the slab of the balcony 4 through the post-construction anchor 10 so that the horizontal force acting on the seismic frame can be transmitted to the existing building 1 in the event of an earthquake. It has become.
Furthermore, the new slabs 9 are provided on the R floor, the fourth floor, and the second floor where the number of braces 8 on the upper and lower floors or the proof strength of the braces 8 change, and are installed horizontally along with the slabs of the balcony 4 via the post-construction anchor 10. It is designed to transmit power.

  On the other hand, on the third floor, since the number of braces 8 on the upper and lower floors or the proof stress of the braces 8 are the same, a large horizontal force is not required to be transmitted, and therefore no new slab 9 is provided.

The lowermost reinforcing beam 7 is integrated with a new slab (transmission reinforcing member) 11 formed between the foundation 12 of the existing building 1 via a post-construction anchor.
Since the lowermost reinforcing beam 7 is integrated with the foundation 12 of the existing building 1, it is buried in the ground to match the level of the foundation 12. For this reason, in order to prevent the corrosion of the steel frame which comprises the reinforcement beam 7, it is SRC structure covered with concrete.

  Further, in the reinforcing columns 6a located at both end portions of the seismic reinforcing frame 5, the number of braces 8 arranged in the vertical direction on the left and right sides is inevitably not equal. The axial force is greater than that of the other reinforcing columns 6b. For this reason, only when the additional axial force of these reinforcement pillars 6a exceeds the margin of the support capability in the foundation part of the existing building 1 to which the additional axial force is transmitted, this is applied to the lower part of each reinforcement pillar 6a. The reinforcement foundation 18 for supporting is added.

  According to the seismic reinforcement structure of the existing building having the above configuration, when the seismic reinforcement frame 5 is installed in the existing building 1 having the same beam span and floor height over the four levels, it is arranged vertically on the left side of the reinforcing column 6b. The number of the braces 8 made and the number of the braces 8 arranged in the vertical direction on the right side of the reinforcing pillar 6b are made equal to each other to reduce the additional axial force acting on the existing building 1 from the reinforcing pillar 6b. Therefore, since it is set within the margin of the support capacity of the foundation 12 of the existing building 1, it is not necessary to construct a new foundation or reinforcement of the foundation 12 of the existing building 1.

  Further, if the additional axial force transmitted from the reinforcing pillars 6a at both ends exceeds the margin of the supporting capacity in the foundation portion of the existing building 1, this is supported at the lower part of each reinforcing pillar 6a. However, the reinforcement location is limited. For this reason, according to this earthquake-proof reinforcement structure, the earthquake-proof reinforcement can be performed by simple construction without giving a big restriction to the use of the existing building 1 as a whole.

  Further, in this seismic strengthening frame 5, one brace 8 is placed on the left side from the upper right corner of the structure composed of the reinforcing columns 6a and 6b and the reinforcing beam 7 with the central reinforcing column 6b as a boundary. Arranged toward the left corner and on the right side from the upper left corner to the lower right corner of the above construction surface, the brace 8 as a whole draws a chevron, improving design. To do.

(Embodiment 2)
Next, FIG. 3 and FIG. 4 show a second embodiment of the present invention, and the same components as those shown in FIG. 1 and FIG.
In this seismic reinforcement frame 15, the brace 8 located on the left side of the central reinforcing column 6c on the left and right sides of the central reinforcing column 6c on the first floor is the upper right corner of the above structural surface. The brace 8 located on the right side is arranged from the upper left corner of the composition surface toward the lower right corner.

  Then, the braces 8 are formed so as to be continuous diagonally upward from the left and right surfaces of the central reinforcing column 6c so as to be parallel to the braces 8 on the first floor from the surfaces left and right by two spans. Has been placed. As a result, the braces 8 are arranged so as to form a triple chevron as a whole in a front view.

  Since the arrangement of the braces 8 is adopted, the number of the braces 8 positioned on the left and right sides is not equal in each reinforcing column 16 that is separated from the central column 6c by 3 spans to the left and right. 15, the additional axial force acting from the reinforcing pillars 6 a, 6 b, 6 c, 16 is set so as to be within the margin of the support capability of the foundation 12 of the existing building 1.

  Further, in this seismic reinforcement structure, the number of left and right braces 8 is the same as in the reinforcing columns 6a and 16 at the ends of both sides where the number of left and right braces 8 is not equal, and the central reinforcing column 6c. However, as shown in FIG. 3, as a result of the arrangement of one brace 8 having different inclination directions on the left and right sides, the lowermost portions and Between the pillar 2 of the existing building 1, a reinforcing wall (transmission reinforcing member) 17 for transmitting the vertical force acting from the reinforcing pillars 6 a, 6 c, 16 to the foundation 12 of the existing building 1 is interposed. Yes.

These reinforcing walls 17 have a structure in which a ribbed steel plate is joined and integrated with the H-shaped steel constituting the reinforcing pillars 6a, 6c and 16, and one side portion is bolted to the reinforcing pillars 6a, 6b and 16. In addition, after the other side portion is embedded in the pillar 2, it is integrated via a construction anchor.
Ribbed steel plates can also be connected and integrated with reinforced concrete walls.

  According to the seismic reinforcement structure of the existing building having the above-described configuration, in addition to obtaining the same operational effects as those shown in the first embodiment, a direction perpendicular to the seismic reinforcement frame 15 as the transmission reinforcement member Since the reinforcing wall 17 having excellent rigidity connected to and integrated with the lowermost portions of the reinforcing columns 6a, 6c, 16 and the columns of the existing building via post-installed anchors is used, the existing building 1 The vertical load acting from the seismic reinforcement frame 15 installed on the outer surface side of the balcony 4 can be reliably transmitted to the foundation 12 of the existing building 1.

  In particular, in the reinforcing columns 6a and 16 having different numbers of braces 8 located on the left and right sides, a larger vertical axial force acts during an earthquake than the other reinforcing columns 6b. However, the reinforcing columns 6a and 16 Since the reinforcing wall 17 is interposed between the existing building 1 and the pillar 2 of the existing building 1, the reinforcing pillars 6a and 16 are firmly integrated with the pillar 2 of the existing building 1 and the axial force is applied to the existing building. Can be transmitted to one foundation 12.

  Furthermore, in this seismic strengthening frame 15, since the braces 8 are arranged so as to form a triple chevron as a whole when viewed from the front, the design is further improved than that shown in the first embodiment. Excellent.

It is a front view which shows the 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a front view which shows the 2nd Embodiment of this invention. It is the IV-IV sectional view taken on the line of FIG. It is a schematic diagram which shows the action form of the axial force to the pillar located between the braces arranged on the column beam construction surface. It is a schematic diagram which shows the state which has arrange | positioned the brace to the frame from which a beam span and floor height differ.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Existing building 2 Column 3 Beam 5, 15 Seismic reinforcement frame 6a, 6b, 6c, 16 Reinforcement column 7 Reinforcement beam 8 Brace (horizontal resistance element)
9,11 New slab (transmission reinforcement member)
12 Foundation 17 Reinforcement wall (Transmission reinforcement member)
18 Reinforcement foundation

Claims (6)

A seismic strengthening structure in which seismic reinforcement frames are arranged along the outer surface of an existing building having a plurality of levels and connected to the column beam frame of the existing building,
The seismic retrofit frame is composed of a plurality of reinforcing columns arranged along the columns of the existing building, a plurality of reinforcing beams arranged along the beams of the existing building, and the reinforcing columns and the reinforcing beams. A horizontal resistance element provided in the construction surface,
Further, in the other reinforcing columns excluding the reinforcing columns located at both ends, the axial force due to the weight of the seismic reinforcing frame acting on each reinforcing column is positioned on the left and right sides of the reinforcing column at the time of an earthquake. The total axial force in each of the reinforcing columns to which the additional axial force in the vertical direction transmitted from the horizontal resistance element is added is within the margin of the support capacity in the existing foundation portion to which the total axial force is transmitted. Seismic reinforcement structure for existing buildings.   The existing building is constructed with column beam frames having the same beam span and floor height, and the seismic strengthening frame is configured so that the proof stress of the horizontal resistance element is substantially equal on the left and right of each of the reinforcing columns. The seismic reinforcement structure for an existing building according to claim 1, wherein   In the seismic retrofit frame, the strength relationship of the horizontal resistance elements on the left and right of each reinforcing column is opposite to the aspect ratio of the aspect ratio obtained by dividing the floor height of the place where the horizontal resistance elements are installed by the span. The seismic reinforcement structure for an existing building according to claim 1, wherein the structure is arranged to be   The seismic strengthening frame is provided with a transmission reinforcement member that transmits the vertical force acting from the reinforcement pillar to the foundation of the existing building between the reinforcement pillar on the lowest floor and the existing building. The seismic reinforcement structure for an existing building according to any one of claims 1 to 3.   The transmission reinforcing member is a reinforcing wall disposed in a direction orthogonal to the earthquake-proof reinforcing frame by being integrated with the lowest part of the reinforcing column and the column of the existing building via a joining means. The earthquake-proof reinforcement structure of the existing building of Claim 4 characterized by these.   The horizontal resistance element is a brace interposed in a diagonal direction of the structural surface, and the seismic reinforcement frame is located on the left side of the central reinforcing column in front view. The brace is arranged from the upper right corner of the construction surface to the lower left corner, and the brace located on the right side is arranged from the upper left corner of the construction surface to the lower right corner. The earthquake-proof reinforcement structure for an existing building according to any one of claims 1 to 5, wherein

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