JP2005240303A - Structural frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structural frame of excellent earthquake resistance sufficiently ensuring the flexural rigidity of earthquake resistant walls and a bend return effect by boundary beams to remarkably enhance the flexural rigidity of the whole frame without impairing the degree of freedom in architectural design. <P>SOLUTION: The earthquake resistant walls 5a, 5b, 5c in a strong axis direction to external force P<SB>1</SB>are arranged parallel with the acting direction of the external force P<SB>1</SB>. The earthquake resistant walls 6a, 6b in a weak axis direction to the external force P<SB>1</SB>are arranged on both sides of the earthquake resistant walls 5a, 5b, 5c in an orthogonal direction to the acting direction of the external force P<SB>1</SB>. The boundary beams 7 are respectively arranged between the earthquake resistant walls 5a, 5b, 5c in the strong axis direction and the earthquake resistant walls 6a, 6b in the weak axis direction. The boundary beams 8 are respectively arranged between the earthquake resistant walls 6a, 6b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structural frame composed of a seismic wall and a boundary beam, and can significantly improve the seismic performance of a building structure.

  As a structural frame combining walls and beams, a structural frame is known in which earthquake-resistant walls are placed facing each other as a core wall in the center of the building, and a boundary beam is bridged between them. For example, in the case of an office building in which shared facilities such as an elevator 20, an elevator hall 21, and a corridor 22 are intensively arranged in the center of the building as shown in FIG. The L-shaped or T-shaped walls respectively disposed therein become the earthquake-resistant walls 23 facing each other, and the beam bridged between the earthquake-resistant walls 23 and 23 is the boundary beam 24.

In particular, the boundary beam 24 has a resistance to reduce bending deformation and rotational displacement of the seismic wall 23, and has a function of increasing the rigidity of the seismic wall 23 and increasing the bending and rotation strength of the seismic wall 23. The bending rigidity of the wall 23 and the bending return effect by the boundary beam 24 can be ensured to increase the bending rigidity of the entire building.
JP2002-35709A JP 2001-336300 A JP 2001-173129 A

  However, in the above-described structural frame, when the width of the core wall composed of the seismic wall 23 and the boundary beam 24 is small, the secondary moment of the cross section of the seismic wall 23 cannot be sufficiently secured, and the boundary beam 24 is also bent back. Only the boundary beam 24 arranged on one side corresponds to each seismic wall 23 and the fall span (distance between the centers of gravity) of the seismic wall 23 cannot be secured sufficiently. There were problems such as making it difficult to ensure bending rigidity.

  The present invention was made in order to solve the above-mentioned problems, and sufficiently secures the bending rigidity of the earthquake-resistant wall and the bending back effect by the boundary beams without impairing the degree of freedom in the architectural design of the core part. The purpose of this study is to provide a structural frame with extremely high flexural rigidity and excellent earthquake resistance.

  The invention according to claim 1 is arranged in parallel to the action direction of the external force and is arranged in a direction that is orthogonal to the action direction of the external force on both sides of the earthquake-resistant wall and a strong axis against the external force. Further, the present invention is characterized by comprising a seismic wall having a weak axis against the external force, and boundary beams disposed between the seismic wall having the strong axis and the seismic wall having the weak axis.

  The invention of the present application is particularly advantageous in that the boundary beams are arranged on both sides of the strong shaft seismic wall, so that the beam can be bent back compared to the conventional structural frame in which the boundary beam is arranged only on one side of the strong shaft seismic wall. Since the weak-axle earthquake resistant wall placed at the tip of the boundary beam has the function of constraining the vertical deformation of the boundary beam, the boundary beam bending back effect can be added. The bending rigidity of the entire frame can be significantly increased. For this purpose, it is not necessary to newly provide a construction surface such as a seismic wall on the tip side of the boundary beam.

  In addition, since the weak-axis seismic wall placed at the tip of the boundary beam acts as a shaft member that restrains the vertical deformation of the boundary beam tip, the strong-axis seismic wall is limited within the length of the limited construction surface. By arranging it as long as possible, it is possible to make a seismic wall with a large second moment of section. It should be noted that securing a sufficient length of the strong shaft earthquake-resistant wall can suppress a decrease in the rigidity of the frame after bending yielding of the beam when the boundary beam is used as a damper.

The specific performance of the structural frame according to the present invention shown in FIGS. 1 and 2 and the conventional structural frame shown in FIG. Compared with specific numerical values expressed in 1, assuming a 9.7m as an outer dimension L of shear walls, also 0.7m a wall thickness t of the shear walls, beam length of the wall length L _W and the boundary beams Walls The ratio to L _b was set to about 1.5, and the beam formation D of the boundary beam was determined with the shear span ratio β = (L _b / D) set to about 1.5.

Incidentally, the ratio of the beam length L _b of the wall length L _W and the boundary beams shear walls was about 1.5, member angular boundary beams in the case of setting the story drift during an earthquake 1/100 This is because it is 1/40 or less which is not excessive in design. In addition, the reason why the beam span D of the boundary beam is set so that the shear span ratio β is about 1.5 is to ensure the deformability by bending.

As a result, the wall cross-sectional area of the earthquake resistant wall is about 4% smaller in the present invention. Wherein bending of the beam back increasing length L _r indicates the length of the bending moment end boundary beams is extended by a shear force to the center of gravity position of the shear walls, also fall span L _t to overturn the structure Frames The distance of the center of gravity of the structure that can be resisted is shown.

table. In FIG. 1, the total value of the sectional moments of each shear wall is slightly better in the conventional example, but in the case of the present invention, the boundary beams are arranged on both sides of the strong shaft shear wall. Considering that the bending resistance of the strong shaft shear wall and the bending back effect of the boundary beam are the same, it can be said that the present invention is 1.89 times better than the conventional example. In addition, it can be seen that the present invention is superior in terms of other performances such as an increased bending back length L _r , a beam formation D, and a fall span L _t .

  Here, each seismic wall is assumed to be an RC structure wall, but is not particularly limited to this, and may be an RC structure wall with a built-in steel frame or an SRC structure wall reinforced with a steel plate. . Moreover, the boundary beam is an RC structure made of high-toughness concrete, and the seismic performance can be remarkably improved by arranging the beam main bars in an X shape or introducing prestress.

  The structural frame according to claim 2 is characterized in that in the structural frame according to claim 1, a corridor is arranged between the strong-axis earthquake-resistant wall and the weak-axis earthquake-resistant wall. In the present invention, by arranging the boundary beam and the corridor at the same position, it is possible to arrange the strong shaft earthquake-resistant wall as long as possible without reducing the floor area of the office room arranged around the common facility. .

  The structural frame according to claim 3 is the structural frame according to claim 1 or 2, characterized in that the weak-axis seismic wall is arranged in the equipment space. By arranging the weak shaft earthquake-resistant wall at such a position and combining this with the embodiment of claim 2, it is possible to easily secure an effective fall span. Therefore, the bending characteristics can be improved.

  In general, in the floor plan of office buildings, shared facilities such as elevators, equipment facilities, and corridors are often arranged in the center, and office rooms are often arranged around them. If applied, it becomes possible to inspect the equipment room from the corridor without entering the office room, and it is easy to secure equipment space because it is not restricted to entering and exiting from the elevator.

  The structural frame according to claim 4 is the structural frame according to any one of claims 1 to 3, wherein the ratio of the wall length of the strong shaft earthquake resistant wall to the beam length of the boundary beam is set to 1.5 or less. It is characterized by.

In the structural frame of the present invention, the ratio α of the member angle with respect to the interlayer deformation is generally determined by a geometrical relationship, where the wall length of the strong shaft earthquake resistant wall is L _{W and} the beam length of the boundary beam is L _b . The ratio α is α = 1 + L _W / L _b . Here, when the limit value of the interlayer deformation angle is 1/100, the member angle of the boundary beam is 1 / (100 / α). The member angle of the boundary beam is, for example, 1/50 to 1/40 in terms of deformation capability in the case of an RC structure.

  In order to keep the member angle of the boundary beam within 1/40 with an interlayer deformation angle of 1/100, α is 1.5. For this reason, setting the α to 1.5 or less is significant in the structure of the structural frame.

  If this is made to correspond to the present invention, the weak shaft shear wall bears almost no bending and exhibits only the shaft rigidity, so that the other ends of the boundary beams arranged on both sides of the strong shaft shear wall (weak shaft) The end of the earthquake-resistant wall side) can be the inflection point of the moment, so that the effective length of the beam can be twice the actual length of the boundary beam. Therefore, for example, even if the dimensions are as shown in FIG.

  The structural frame according to claim 5 is characterized in that, in the structural frame according to any of claims 1 to 4, the shear span ratio of the boundary beam is set to 1.5 or more.

The shear span ratio β of the boundary beam is β = L _b / D = M / Q · D, and β = L _b / 2 · D in the case of anti-symmetric bending. The shear span ratio β is β = 2L _b / 2 · D = L _b / D.

  The shear span ratio β is important for securing the deformability of the beam by bending, and if this value is small, shear fracture is likely to occur. However, in the present invention, this shear span ratio β can be secured large. .

  It is also possible to increase the shear span ratio β of the boundary beam by increasing the number of ends of the strong shaft on the shear wall side and reducing the number of weak shafts on the side of the shear wall as much as possible when arranging the boundary beams. .

  As a bar arrangement method in this case, for example, as shown in FIGS. 6A, 6B, and 6C, a method that does not arrange a two-stage bar at the end of the weak axis on the side of the earthquake-resistant wall, There is a method of reducing the anchoring length of the main reinforcement arranged at the end of the earthquake-resistant wall side, and a method of narrowing the upper and lower main reinforcement arranged at the boundary beam at the end of the weak-axis earthquake-proof wall side.

Since the main reinforcement of the boundary beam is arranged in this way, the bending moment of the boundary beam is large at the end of the strong shaft side as shown in FIG. At the end, it is 0 or a value close to 0. Therefore, since M = L _b · Q, the shear span ratio β is β = M / Q · D = L _b · Q / Q · D = L _b / D.

On the other hand, in the case of a boundary beam that bears the same bending moment at both ends as shown in FIG. 5B, M = L _b · Q / 2, so β = M / Q · D = L _b · Q / 2 · Q · D = L _b / 2 · D.

  From the above, in the present invention, since the shear span ratio β can be increased as compared with the normal case, it is easy to ensure the bending deformation ability of the beam. This feature is the same even when the boundary beam bears some bending moment at the end of the weak-walled seismic wall.

  The invention of the present application is particularly advantageous in that the boundary beams are arranged on both sides of the strong shaft seismic wall, so that the beam can be bent back compared to the conventional structural frame in which the boundary beam is arranged only on one side of the strong shaft seismic wall. Therefore, the bending rigidity of the earthquake-resistant wall and the bending back effect by the boundary beam can be sufficiently secured, and the bending rigidity of the entire structure can be greatly increased. Can be provided. Moreover, the freedom degree in the architectural design of the core part is not impaired.

  Moreover, structural performance such as the beam formation of the boundary beam, the shear span ratio, and the member angle of the beam can be enhanced as a frame in which the earthquake resistant wall and the boundary beam are combined.

  FIG. 1 shows a standard floor of an office building, in which an elevator 1, an elevator hall 2 and a corridor 3 are arranged as shared facilities in the center, and an office room 4 is arranged around them. A plurality of elevators 1 and elevator halls 2 are arranged in parallel in the Y-axis direction, and a corridor 3 is continuously arranged in a U-shape so as to surround both sides and the lower periphery of these shared facilities.

FIGS. 2 (a) and 2 (b) show the structural frame of the present invention applied to the shared facilities of the office building, between the elevators 1 and 1, and between the elevator hall 2 and the office room 4. FIG. The partition walls 5a, 5b, 5c respectively disposed between the elevator 1 and the office room 4 are strong-axis earthquake-resistant walls (hereinafter referred to as “earthquake-resistant walls 5a, 5b, 5c”) against the external force P ₁ acting in the X-axis direction. Is built).

Also, it built as respectively arranged partition walls 6a, 6b are weak axis with respect to the external force P ₁ shear wall (hereinafter referred to as "shear walls 6a, 6b") between each elevator 1 and elevator hall 2 and corridors 3 Yes.

  Boundary beams 7 are respectively arranged between the earthquake-resistant walls 5a, 5b and 5c and the earthquake-resistant walls 6a and 6b on both sides thereof, and between the earthquake-resistant walls 6a and 6b and between the earthquake-resistant walls 6a and 6a. Boundary beams 8 are respectively arranged. Furthermore, pillars 9 are arranged around the office room 4 at predetermined intervals, and large beams 10 are bridged between the pillars 9 and 9.

  The seismic walls 5a, 5b, 5c, the seismic walls 6a, 6b, and the pillars 9 are generally arranged continuously from the lowest floor to the top floor, and the boundary beams 7 and 8 and the large beams 10 are all floors of each floor. Placed in the part. The boundary beam 7 can be arranged not only on the floor portion of each floor.

In such a configuration, with respect to the external force P ₁ acting on the X-axis direction, the shear wall 5a of the strong axis, 5b, 5c, the boundary beams 7 arranged on both sides of the bending rigidity and the shear wall of the shear walls The bending rigidity of the entire frame can be increased in order to sufficiently secure the bending return effect due to.

Incidentally, with respect to the external force P ₂ acting on the Y-axis direction, the elevator 1 and elevator Walls 6a disposed on both sides of the hole 2, acts as Shear Walls 6b is strong axis, each shear wall 5a, 5b, 5c Works as a weak axis earthquake-resistant wall.

  3 (a) and 3 (b) show a modification of the present invention. In the case of FIG. 3 (a), between the strong-axis earthquake-resistant walls 5a, 5b and 5c and the weak-axis earthquake-resistant walls 6a and 6b, FIG. Corridor 3 is arranged. As a result, by arranging the boundary beam 7 and the corridor 3 at the same position, it is possible to make the strong shaft earthquake-resistant walls 5a, 5b, 5c without reducing the floor area of the office room 4 arranged around the common facility. Can be placed as long as possible.

  In the case of FIG. 3 (b), the weak shafts 6 a and 6 b are disposed in the equipment space 11. Since the weak shaft earthquake-resistant walls 6a and 6b are arranged at such positions, an effective fall span can be easily secured by combining this with the embodiment of claim 2, and therefore, the plan plan The bending characteristics can be improved without hindering the above.

  In addition, it is possible to inspect the equipment room from the corridor 3 without entering the office room 4, and since it is not restricted to entering and exiting from each elevator 1, it is easy to secure the space of the equipment space 11.

  4 (a) and 4 (b) show a modified example of the present invention, in which the strong-axis seismic walls 5 are arranged in a C shape and a cross shape, respectively, and can be freely selected according to the plan plan. it can.

  The present invention can provide a building having extremely high earthquake resistance by sufficiently securing the bending rigidity of the earthquake-resistant wall and the bending return effect by the boundary beam and greatly increasing the bending rigidity of the entire structure.

It is a top view of the reference floor of the office building to which the structural frame of the present invention is applied. The structural frame of this invention is shown, (a) is the one part longitudinal cross-sectional view, (b) is the cross-sectional view. (a), (b) is a top view of the reference | standard floor of the office building to which the structural frame of this invention was applied. (a), (b) is a cross-sectional view which shows the structural frame of this invention. (a), (b) is a stress diagram of the boundary beam. (a), (b), (c) is a partial longitudinal cross-sectional view which shows the bar arrangement method of a boundary beam edge part. An office building to which a conventional structural frame is applied is shown, (a) is a plan view of a reference floor, (b) is a partial longitudinal sectional view thereof, and (c) is a transverse sectional view thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elevator 2 Elevator hall 3 Corridor 4 Office room 5 Earthquake-resistant wall 5a Earthquake-resistant wall (partition wall)
5b Earthquake resistant wall (partition wall)
5c Earthquake resistant wall (partition wall)
6 Seismic wall 6a Seismic wall (partition wall)
6b Earthquake resistant wall (partition wall)
7 Boundary beam 8 Boundary beam 9 Column 10 Large beam 11 Facility space

Claims (5)

  Weak walls against the external force, which are arranged in parallel to the direction of external force, and weak against the external force, which are arranged on both sides of the earthquake-resistant wall in a direction perpendicular to the direction of the external force. A structural frame comprising an earthquake-resistant wall of a shaft and boundary beams arranged between the earthquake-resistant wall of the strong axis and the earthquake-resistant wall of the weak axis.   2. The structural frame according to claim 1, wherein a corridor is disposed between the strong-axis seismic wall and the weak-axis seismic wall.   3. The structural frame according to claim 1 or 2, wherein the weak-axis seismic wall is arranged in an equipment space.   The structural frame according to any one of claims 1 to 3, wherein a ratio between a wall length of the strong shaft earthquake-resistant wall and a beam length of the boundary beam is set to 1.5 or less. The structural frame according to any one of claims 1 to 4, wherein a shear span ratio of the boundary beam is set to 1.5 or more.

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