JP7106305B2 - Structural columns and seismically isolated buildings - Google Patents

Description

TECHNICAL FIELD The present invention relates to an inverse construction method, and more particularly to a structure pillar used in the inverse construction method, and a base-isolated building using this structure pillar.

The reverse construction method is a construction method in which the construction of the basement floor and the ground floor is performed in parallel, and is known as an effective construction method for shortening the construction period of a high-rise building having a basement floor. In general, when the reverse casting method is used, a pile hole is drilled by driving a casing into the ground. After erecting, pour concrete and construct piles.

Next, the beams and floors of the first floor are first constructed on the upper part of the structure column, and while excavating the basement floor part using this as the gantry (construction floor), excavation and frame work are carried out sequentially downward from the first basement floor. Repeat the construction of After excavating to the level with the floor of the foundation, the reinforcement for the foundation is arranged and concrete is placed to complete the underground frame. By carrying out these works underground while constructing the ground floor at the same time, the construction period can be significantly shortened compared to the conventional construction method (sequential construction) in which the construction of the ground floor is completed after the construction of the basement floor is completed. can be shortened to

On the other hand, when the reverse construction method is used, the basement frame is constructed downward while supporting the load of the structure of the ground floor, which is constructed in advance, by the structural columns. For this reason, it has been considered unsuitable for seismic isolation of buildings. Under such circumstances, as disclosed in Patent Document 1 and Patent Document 2, even if the reverse construction method is implemented, a seismic isolation device is installed on the structure column that constitutes the frame of the basement floor. Construction methods for constructing buildings have been proposed. In Patent Document 1, a temporary jack is placed between the foundation of the underground frame and the foundation beam, and the temporary jack temporarily receives the axial force (the weight of the building being constructed) applied to the structure column, and the structure column A construction method of cutting and arranging the seismic isolation device is disclosed.

Further, in Patent Document 2, a structure column having a configuration in which a steel pipe having a circular cross section is arranged between the lower half buried in the foundation and the upper half constituting the permanent column of the basement floor It is disclosed to employ The steel pipe of the structure column disclosed in Patent Document 2 is provided with an opening into which the seismic isolation device can be inserted on the side surface. After constructing the underground frame, the seismic isolation device is inserted into the steel pipe through the opening, and the gap between the seismic isolation device and the upper half or the lower half is filled with grout material. It is disclosed that after the grout material has hardened, the side wall of the steel pipe (parts other than the opening) is cut, and the axial force applied to the structural column is transferred to the seismic isolation device.

Certainly, according to the construction methods disclosed in Patent Literatures 1 and 2, it is possible to construct a base-isolated building by installing a seismic isolation device on the main column even when implementing the reverse construction method. However, in the construction methods disclosed in any of the documents, it is necessary to cut a part of the structural column or the steel pipe portion and transfer the load borne by the structural column to the seismic isolation device. For this reason, it takes time and effort to install a jack in a narrow space and to cut the structural column, and there is a risk of subsidence due to the change of load.

On the other hand, Patent Literature 3 proposes implementing the reverse hammering method using a structure column having a seismic isolation device pre-arranged between the lower half and the upper half. By burying the structure column with the seismic isolation device installed in advance, the above problems can be solved, and it becomes possible to construct the seismic isolation building safely by the reverse construction method.

Japanese Patent No. 3648651 Japanese Patent No. 3637945 JP-A-11-30053

By using the structure column having the configuration disclosed in Patent Literature 3, it is possible to simplify the installation work because the work associated with retrofitting the seismic isolation device becomes unnecessary. However, as described in paragraph [0016], the structural column of Patent Document 3 does not ask about the cross-sectional shape, and the column material constituting the lower half and upper half separated by the seismic isolation device There is only an example of using the same material for Cross H-shaped steel with an open cross-section (a member in which H-shaped cross-section steel materials are combined in two directions) is generally used for structural columns. Since it is not possible to bear the burden, buckling stoppers are installed in the middle of the story, and the depth that can be excavated in one process (cycle) becomes shallow, increasing the number of processes and the work on site. Precast concrete structural columns with large axial strength have also been developed, but in high-rise buildings where high axial force acts, the weight increases, so lifting of structural columns with cranes and burying them in the ground are required. becomes difficult.

Therefore, in the present invention, a structural column equipped with a seismic isolation device that solves the above problems, capable of bearing a high axial force and capable of suppressing an increase in weight, and the structural column. The purpose is to provide a seismically isolated building using pillars.

A structural column according to the present invention for achieving the above object is a structural column used in the reverse construction method, and includes an upper half portion having a closed cross section constituting a permanent column of the basement floor, and a lower half portion having an open cross section to be embedded, and a seismic isolation device interposed between the upper half portion and the lower half portion. In this way, by using solid cross-section members for the main frame pillars and open cross-section members for the parts buried in the foundations and piles, it is possible to reduce the load on the crane during lifting while increasing the height of the crane. A pillar that can bear the force can be rationally constructed.

In addition, in the structure column having the above characteristics, the upper half is composed of a steel pipe column with a base plate at the lower end, and the lower half is a cross H-beam steel column with a base plate at the upper end. The top half is filled with concrete after installation. With this feature, the axial force borne by the upper half can be efficiently transmitted to the lower half through the seismic isolation device. Moreover, the weight of the upper half is suppressed during lifting, and the resistance to axial force can be increased by filling concrete after installation.

In addition, in the structural column having the characteristics described above, the base plate joined to the lower half portion is configured to be thicker than the base plate joined to the upper half portion. This increases the effect of dispersing the axial force within the base plate, and even if the bearing area (cross-sectional area) of the lower half is smaller than that of the upper half, the transmission of axial force (stress) to the lower half is minimized. It can be done smoothly. As a result, the amount of steel material for the lower half can be reduced, leading to cost reduction.

A base-isolated building according to the present invention is characterized in that any one of the structural columns described above is applied to a core portion where elevators are concentrated. As a result, the elevator does not pass through the seismic isolation layer, so there is no need for a special mechanism that allows the rails and supporting members to follow the deformation during an earthquake.

According to the structural column having the characteristics described above, even when a super high-rise building is to have a seismic isolation structure underground, it can be constructed rationally by the reverse construction method.

It is a figure which shows the structure of the structure pillar which concerns on embodiment. It is a figure which shows the mode at the time of construct|constructing a base-isolated building using the structure pillar which concerns on embodiment, and is a figure which shows the state which buried|buried the structure pillar. It is a figure for demonstrating the process of burying a structural pillar. It is a figure which shows the mode at the time of constructing|constructing a base-isolated building using the structure pillar which concerns on embodiment, and is a figure which shows the state which installed the gantry on the upper part of the structure pillar. FIG. 10 is a diagram showing a state in which a base-isolated building is constructed using structural columns according to the embodiment, and is a diagram showing a state in which excavation of the basement has been completed, and construction of the skeleton of the basement floor and the skeleton of the ground floor has proceeded. is. It is a figure which shows the state which has arrange|positioned the temporary fixing member to the structure pillar.

EMBODIMENT OF THE INVENTION Hereafter, embodiment which concerns on the structure column of this invention, and a base-isolated building is described in detail with reference to drawings. It should be noted that the forms shown in the following embodiments are part of preferred forms for carrying out the present invention, and the form of each element and constituent members can be changed as appropriate without departing from the characteristics thereof. can.

First, with reference to FIG. 1, the structure of the structural column according to the present invention will be described. In addition, FIG. 1(A) is a view showing a side view of the structural column, and FIG. 1(B) is a view showing a plan view of the upper half. In addition, FIG. 1(C) is a diagram showing a planar form of the seismic isolation device, and FIG. 1(D) is a diagram showing a planar form of the lower half.

[Structure of structural columns]
The structural column 10 according to this embodiment has an upper half portion 12 , a lower half portion 16 , and a seismic isolation device 14 . The upper half 12 is an element that constitutes the permanent pillar of the basement floor, and is made of a member having a closed cross section. Specifically, it can be a steel pipe column. By using such a member for the column material constituting the upper half part 12 of the structure column 10 and filling it with concrete after installation, the structure column 10 is buried and the column is cast after the basement floor is excavated. It becomes possible to configure the permanent pillar without replacing it. Moreover, the resistance to the axial force can be increased after installation while suppressing the weight during lifting.

The upper half 12 of such a configuration is provided with a base plate 12a at its lower end. The base plate 12a is configured to have a planar shape that matches or approximates the upper plate 14a that constitutes the seismic isolation device 14 . By adopting such a configuration, it is possible to efficiently support the axial force borne by the permanent column on the seismic isolation device 14 .

The lower half 16 is an element that is buried (deeper than the foundation) in a foundation and a pile (constructed by filling concrete 22 in a casing 20 (see FIG. 2)) buried in this foundation. , and a member having an open cross section. Specifically, a cross H-shaped steel column and the like can be mentioned. By configuring the column material that constitutes the lower half portion 16 of the structural column 10 in this way, the weight of the structural column 10 as a whole can be reduced (suppressed). Therefore, when the reverse hammering method is carried out, the structure column 10 can be lifted in a suspended state, loaded into the casing 20, and buried.

The lower half 16 of such a configuration is provided at its upper end with a base plate 16a. The base plate 16a is configured to have a planar shape that matches or approximates the lower plate 14c that constitutes the seismic isolation device 14. As shown in FIG. With such a configuration, the axial force borne by the permanent column (upper half 12) transmitted via the seismic isolation device 14 is efficiently transmitted to the lower half 16 and supported. becomes possible.

The seismic isolation device 14 is an element that isolates vibration between the upper half 12 and the lower half 16, and is preferably an element capable of isolating at least horizontal vibration. Specific examples include a laminated rubber type structure, a slide bearing structure, a rolling bearing structure, and the like. For example, the seismic isolation device 14 of the example shown in FIG. 1 is a laminated rubber type structure, and a laminated rubber 14b is provided between an upper plate 14a and a lower plate 14c.

By providing the seismic isolation device 14 between the upper half portion 12 and the lower half portion 16, even if the cross-sectional shapes and sizes of the upper half portion 12 and the lower half portion 16 are different, a large axial force can be transmitted. The seismic isolation device 14 can play the role of a buffer area for achieving this.

Further, in the structural column 10 of the present embodiment, the base plate 16a of the lower half portion 16 is thicker than the base plate 12a of the upper half portion 12. As shown in FIG. With such a configuration, the axial force dispersion effect in the base plate 16a is increased, and the area (cross-sectional area) of the support surface of the open cross-section member that constitutes the lower half portion 16 constitutes the upper half portion 12. Even if it is much smaller than the member or the lower plate 14 c of the seismic isolation device 14 , the axial force (stress) can be smoothly transmitted to the lower half portion 16 . In addition, there is no risk of damaging the lower plate 14c of the seismic isolation device 14 due to stress concentration.

[action, effect]
According to the structure column 10 having such a configuration, since the seismic isolation device 14 is interposed in the column, there is no need to install the seismic isolation device 14 after the structure column 10 is installed. In addition, since the upper half is made of pillars that can be used as permanent pillars of the underground frame, there is no need to replace the pillars after excavating the basement floor. Furthermore, since the lower half portion 16 is made of a steel frame with an open cross section, the overall weight of the structural column 10 can be reduced. This facilitates the work of burying the structural column 10 .

Further, by interposing the seismic isolation device 14 between the upper half portion 12 and the lower half portion 16, it is possible to efficiently transmit the axial force between them.

[Example of application to base-isolated buildings]
Next, a base-isolated building that employs the structure columns configured as described above will be described with reference to FIGS. 2 to 5. FIG. In constructing a high-rise building, the base-isolated building according to the present embodiment is constructed by arranging the structural column 10 described above in a core portion where elevators are concentrated. In a high-rise building having a basement floor, an elevator shaft is a space that extends from the skeleton 32 of the basement floor to the upper part of the skeleton 30 of the ground floor. Therefore, if a seismic isolation device is arranged at the boundary between the basement floor and the ground floor, when an earthquake occurs, a phase shift occurs between the basement frame 32 and the ground floor frame 30, and the elevator shaft There is a risk that distortion will occur in the Therefore, the rails and support members that make up the elevator require a special mechanism that follows the deformation of the elevator shaft when an earthquake occurs.

By arranging the seismic isolation device 14 at the lower end of the elevator shaft as in this embodiment, the elevator shaft can obtain the same seismic isolation effect as the frame on the ground floor, preventing damage in the event of an earthquake. can be reduced. Therefore, the special mechanism as described above is no longer necessary.

When constructing a base-isolated building having such a configuration by adopting the reverse construction method, for example, the structural columns according to the above-described embodiment may be applied as follows. First, as shown in FIG. 2, the structural column 10 is buried in the ground. The burial of the structure column 10 can be performed in the same manner as the normal reverse construction method. Specifically, as shown in FIG. 3A, the casing 20 is driven into the ground and the inside is excavated. Next, as shown in FIG. 3(B), a reinforcing bar (not shown) is arranged and the truss center 10 is inserted into a pile hole filled with concrete 22 in the casing 20, and the concrete 22 is waited for hardening (FIG. 3(C) )). After the concrete 22 hardens, the inside of the casing 20 is backfilled as shown in FIG. 3(D) in order to prevent the structural column 10 from buckling.

Here, the structure column 10a embedded in the portion other than the core portion indicated by the dashed line A in FIG.

Next, as shown in FIG. 4, the gantry 24 is constructed by constructing the beams and floor surfaces that constitute the floor of the first floor above the structuring columns 10 and 10a. Here, a seismic isolation device 14 is arranged at the upper end of the structure column 10a embedded in a portion other than the core portion (the boundary portion with the frame of the ground floor), and the gantry 24 is positioned above the seismic isolation device 14. configured to After constructing the gantry 24, construction of the frame 30 of the ground floor is advanced, and excavation work for constructing the frame 32 of the basement floor is carried out.

As shown in FIG. 5, the excavation work of the underground floor is carried out so that the seismic isolation device 14 provided on the structure column 10 is exposed and the lower half portion 16 is buried in the foundation. A skeleton 32a that serves as a core is constructed on the upper part of the device 14. As shown in FIG. When constructing the seismic isolation building 40 by such a method, temporary fixing as shown in FIG. It is preferable to embed the structural column 10 while the member 18 is installed.

The temporary fixing member 18 prevents the lower half 16 and the upper half 12 from being displaced relative to each other in the horizontal direction. It plays the role of preventing the seismic isolation device 14 from extending in the vertical direction. Therefore, by providing the temporary fixing member 18, even if the structural column 10 according to the embodiment is lifted in a suspended state and inserted into the casing 20, the upper half portion 12 and the lower half portion 16 are displaced. There is no possibility that the seismic isolation device 14 will be adversely affected by a tensile load.

By implementing the reverse construction method using the structural column 10 according to the above-described embodiment and constructing the seismic isolated building 40, there is no need to change the load of the structural column 10, etc., and the seismic isolation device 14 Installation can be facilitated. In addition, since the construction proceeds with the axial force applied to the seismic isolation device 14, there is less risk of sudden settlement due to compression of the rubber portion compared to the method of changing the load.

10, 10a... Structural column, 12... Upper half part, 12a... Base plate, 14... Seismic isolation device, 14a... Upper plate, 14b... Laminated rubber, 14c... Lower plate 16 Lower half 16a Base plate 18 Temporary fixing member 20 Casing 22 Concrete 24 Gantry 30 Frame 32 ……Frame, 32a……Frame, 40……Seismic isolation building.

Claims (3)

A structural column used in the reverse construction method,
an upper half of a closed section member having a base plate at the lower end and constituting a permanent pillar of the basement floor;
A base plate is provided at the upper end, and a lower half of the open cross-section member buried deeper than the foundation,
A seismic isolation device is interposed between the upper half and the lower half ,
The structural column , wherein the base plate joined to the lower half is thicker than the base plate joined to the upper half . The upper half is composed of a steel pipe column ,
The lower half is composed of a cross H-shaped steel column ,
The structural column according to claim 1, wherein the upper half portion is filled with concrete after installation. A base-isolated building constructed by a reverse construction method using the structural column according to claim 1 or 2 .

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