JP2014091943A - Construction method for base-isolated foundation structure, and base-isolated foundation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that enables bar arrangement to be performed with a predetermined degree of accuracy and that can achieve labor saving for work.SOLUTION: This method includes the steps of: mounting reinforcement anchoring members, which are arranged in predetermined positions, respectively, and which comprise a plurality of anchorage parts for screwing and anchoring respective reinforcements, in predetermined positions on a precast concrete panel; installing the precast concrete panel on a base-isolating device; and screwing and anchoring the plurality of reinforcements, which configure a column base part of an upper structure, to the plurality of anchorage parts, respectively.

Description

  The present invention relates to a method for constructing a base-isolated base structure and a base-isolated base structure constructed by the method.

  The base isolation structure is constructed by interposing a base isolation unit composed of laminated rubber or the like on the base part of an upper structure such as a building or a condominium. When constructing the base isolation structure, a joint is provided to join the seismic isolation device and the pillars and underground beams to support the upper structure above it. It is constructed by installing a base plate on a seismic isolation device, attaching a formwork, arranging a large number of reinforcing bars, and driving concrete from the top with a high placement height.

  However, when the construction is performed according to such a procedure, it takes time and there is a problem that considerable cost and construction period are required. This is because it is necessary to assemble a scaffold for the bar arrangement work, and when concrete is placed on site, it takes time to cure.

  In view of this problem, a construction method that can rationalize the construction of the upper foundation and greatly improve the workability has been proposed (for example, see Patent Document 1). In this method, after the seismic isolation device is installed on the lower foundation, a PCa (precast concrete) board formed in advance in a flat plate shape is placed on the seismic isolation device and fixed by an anchor member, and then placed on the upper part of the PCa board. The upper foundation of RC (steel reinforced concrete) structure is formed integrally with the anchor member.

JP 2012-67524 A

  In the method described in Patent Document 1, after fixing the PCa board, a bottom mold is installed on the upper surface level of the PCa board, foundation reinforcement is placed on the upper part, concrete is placed, and the upper part of the RC structure is placed. Install the foundation. For this reason, in addition to the crossing of a large number of reinforcing bars, it is difficult for the reinforcing bars to move due to the side pressure of the concrete when placing concrete, and to keep the position of the reinforcing bars within a predetermined accuracy. Moreover, if the accuracy of the position of the reinforcing bar does not fall within a predetermined range, it becomes difficult to construct the upper precast concrete (PC) column.

  In general, the leg portion of the column main bar constituting the PC column requires a predetermined fixing length, and is bent and arranged from the upper surface of the seismic isolation device as an anchor bar by bending the tip. Such bar arrangement is difficult to work, and the amount of reinforcing bars increases, resulting in an increase in material costs.

  Therefore, it has been desired to provide a method and the like that can fix the position of the column main bars accurately and firmly, perform the bar arrangement with a predetermined accuracy, and realize labor saving.

  In view of the above problems, the present invention is a method for constructing a base-isolated base structure, each of which is disposed at a predetermined position and includes a plurality of fixing portions for screwing and fixing each reinforcing bar. The fixing base is attached to a predetermined position on the precast concrete board, the precast concrete board is installed on the seismic isolation device, and the column base of the superstructure is constructed in each of the multiple fixing parts. Screwing and fixing each of a plurality of reinforcing bars.

  By providing the construction method of the base isolation structure of the present invention and the base isolation base structure constructed by this method, the accuracy of the column main bar position can be improved, and the work of bar arrangement can be saved. . Moreover, since a precast concrete board is used, the work of formwork can be saved.

The figure which illustrated the seismic isolation foundation constructed | assembled by the method of this invention. The figure which illustrated the place which attached the reinforcing bar fixing member to the precast concrete board. The flowchart which showed the flow of the process implemented by the method of this invention.

  FIG. 1 is a diagram illustrating a base-isolated base structure constructed by the method of the present invention. This seismic isolation substructure includes, for example, a floor slab 11 constructed by placing a plurality of anchor bolts 10 at predetermined positions and placing concrete, and a bar arrangement on the floor slab 11, and an insert It has a lower base 15 for installing the seismic isolation device 14, which is constructed by placing the lower base plate 13 including the hardware 12 so as to float, attaching a formwork, and placing concrete.

  A plurality of anchor bolts 10 projecting from the floor slab 11 in the vertical direction are embedded in the lower foundation 15 to fix the lower foundation 15 to the floor slab 11. The insert hardware 12 is, for example, a hollow cylindrical shape, the inside of which is threaded, and a nut shape into which a bolt can be screwed.

  The configuration shown in FIG. 1 is an example, and the lower foundation 15 may be constructed directly on the ground, or the lower foundation plate 15, the lower base plate 13, and the lower flange plate 14 a of the seismic isolation device 14 described later by the anchor bolt 10. May be connected. In FIG. 1, the lower base plate 13 is embedded in the lower base 15 so that the upper half is exposed, but may be embedded so that only the surface is exposed. Also, the lower foundation 15 can be precast as in the upper foundation described later.

  The seismic isolation device 14 includes a lower flange plate 14a, an upper flange plate 14b, and a laminated rubber 14c disposed therebetween. This configuration is an example, and a seismic isolation device for a rolling base isolation bearing with a sphere interposed between two plates, a protrusion with a fixed curvature at one end is attached to one plate, A seismic isolation device or the like of a sliding seismic isolation bearing configured to be slid may be used.

  A plurality of holes through which bolts are passed are formed in the lower flange plate 14a and the upper flange plate 14b. For this reason, the seismic isolation device 14 is firmly fixed to the lower foundation 15 by inserting the bolt into the insert hardware 12 provided in the lower base plate 13 of the lower foundation 15 via the lower flange plate 14a and screwing it. Is done. As an example, the laminated rubber 14c of the seismic isolation device 14 is formed by alternately laminating sheet-like rubber and steel plates, and the periphery thereof is covered with protective rubber.

  FIG. 1 illustrates the structure of the lower foundation 15, the configuration of the seismic isolation device 14, the connection thereof, and the like, but these may be any structure, configuration, and connection method known so far. .

  In the conventional seismic isolation base structure, the upper base plate is installed on the seismic isolation device 14, the formwork is attached, the reinforcement is placed, and the concrete is placed to construct the upper foundation. However, in this procedure, it is necessary to assemble a scaffold to perform bar arrangement, and curing is necessary for a certain period after placing concrete, which is costly and requires a long construction period.

  For this reason, in the present invention, the upper foundation is precast, and a precast concrete (PCa) board 16 manufactured in advance is used. The PCa board 16 is a rectangular plate made of concrete or reinforced concrete, and an upper base plate 18 including an insert hardware 17 is embedded so that the lower half is exposed. The upper base plate 18 is not limited to this, and may be embedded so that only the surface is exposed.

  An insert hardware 20 for attaching a plurality of anchor bolts 19 is also embedded in the PCa board 16. The insert hardware 20 is a hollow cylinder and has a nut shape in which the inside is threaded. For this reason, the anchor bolt 19 is screwed and fixed, and the structure constructed on the upper part can be firmly fixed.

  On the PCa board 16, a reinforcing bar fixing member 21 provided with a plurality of fixing portions, each of which is disposed at a determined position and screwed to fix each reinforcing bar, is attached to the determined position. The reinforcing bars here are column main reinforcing bars that are reinforcing bars extending in the vertical direction that constitute the column bases of the structure. An insert hardware for attaching the reinforcing bar fixing member 21 is also embedded in the PCa board 16. This insert hardware is also a nut-like one having a hollow cylindrical shape and the inside being threaded, similar to the insert hardware 12 and 17.

  The reinforcing bar fixing member 21 may have a shape and configuration as shown in FIG. 2, for example. The reinforcing bar fixing member 21 shown in FIG. 2 is disposed in a steel rectangular frame-like member by welding a steel hollow cylindrical fixing portion 22 at a predetermined interval. Has been. As the frame-like member, for example, four L-shaped section steels that are connected by welding their end portions or the like can be used.

  The reinforcing bar is a rod-shaped steel material provided with spiral irregularities called ribs on the outer surface, and irregularities are also formed in the fixing portion 22 so as to fit the ribs. Specifically, the unevenness formed in the fixing unit 22 is a screw thread and a screw groove. For this reason, it can fix to the fixing part 22 by screwing a reinforcing bar.

  For example, a mechanical joint fixing plate can be adopted as the fixing unit 22. The fixing plate has a hollow cylindrical member that is screwed in, and includes a protrusion provided so as to protrude from the outer surface of the hollow cylindrical member over the entire circumference. By providing this protrusion part, a contact area with concrete becomes large and it can fix firmly in concrete. In addition, when fixing is not enough only by screwing, it is also possible to pour an adhesive or the like between the fixing portion 22 and the reinforcing bar to fix the fixing more firmly. In addition, when the fixing unit 22 includes an injection port for injecting an adhesive or the like, it can be injected from the injection port.

  The rebar fixing member 21 is provided with a fixing portion 22 at a predetermined position, and is firmly fixed at a predetermined position on the PCa board 16, so that the accuracy of the position of the column main bar can be improved. Can be simplified. Further, when the column main reinforcement is screwed and fixed, the height level of the column main reinforcement can be adjusted by the screwing depth. Thereby, it is possible to reduce the trouble of cutting the column main bars that occurs when adjusting the level of the column main bars.

  Further, since the PCa board 16 is used, it is not necessary to attach a formwork and cast concrete, and it is possible to realize labor saving of the formwork work.

  In addition to the above-mentioned various insert hardware, the PCa board 16 is integrated with a ground beam which is a reinforcing bar for a beam assembled on the ground, by attaching a hanging jig. Suspension is possible and the conveyance to the seismic isolation apparatus 14 can be made efficient.

  The hanging jig has, for example, a ring-shaped or bowl-shaped tip, an end embedded in concrete and expanded so as to be firmly fixed, and has a large surface area (for example, a plurality of protrusions). It is said that the The hanging jig may be attached at any position where the PCa board 16 is appropriately suspended and transported, and any number may be provided. For the suspension of the PCa board 16, a transport device such as a crane provided with a hook portion that can hook the tip of a hanging jig is used.

  From the above, the base isolation structure of the present invention is attached to at least the base isolation device 14, the PCa panel 16 installed on the base isolation device 14, and the PCa panel 16. The reinforcing bar fixing member 21 includes a plurality of fixing portions 22 that are disposed at positions and fix each of the reinforcing bars by screwing.

  With reference to the flowchart shown in FIG. 3, the method of constructing a seismic isolation foundation will be described in detail. The method starts from step 300, and in step 310, the reinforcing bar fixing member 21 is attached to the PCa board 16 manufactured in advance. First, the position of the insert hardware provided on the PCa board 16 is confirmed, and the holes provided in the frame-shaped member of the reinforcing bar fixing member 21 and the insert hardware are positioned on the same straight line in the vertical direction. In addition, the reinforcing bar fixing member 21 is disposed on the PCa board 16. Then, a bolt is screwed into each insert hardware, and the reinforcing bar fixing member 21 is attached and fixed to the PCa board 16. Further, the anchor bolt 19 is screwed and attached to the insert hardware 20 embedded in the PCa board 16. Then, it becomes as shown in FIG.

  Next, in step 320, the lower foundation 15 is constructed, and the seismic isolation device 14 is installed on the lower foundation 15. If necessary, before constructing the lower foundation 15, construct a floor slab 11 in which a plurality of anchor bolts 10 are embedded, and then arrange the bars as described above, and arrange the lower base plate 13. The lower foundation 15 can be constructed by attaching a formwork, placing concrete, and curing for a certain period.

  The lower foundation 15 may be constructed on-site in this way, or it can be constructed by precasting a precast concrete machine manufactured in advance and fixing it to the ground or the floor slab 11 with anchor bolts or the like. is there. In terms of shortening the construction period, precasting is desirable. For the concrete, for example, highly fluid concrete or non-shrinkable mortar can be used in order to ensure the filling property.

  Here, the reinforcing bar fixing member 21 is attached to the PCa board 16 in step 310, and the lower base 15 is constructed and the seismic isolation device 14 is installed in step 320, but this order may be reversed. However, it can also be performed in parallel. Further, the structure of the lower foundation 15, the structure of the seismic isolation device 14, the connection thereof, and the like may be any structure, structure, and connection method known so far.

  In step 330, the PCa board 16 to which the reinforcing bar fixing member 21 is attached is installed on the seismic isolation device 14. The PCa board 16 has a reinforcing bar fixing member 21 attached to one surface, and the upper base plate 18 is exposed on the other surface which is the back surface thereof. The exposed surface of the upper base plate 18 and the upper flange plate 14b of the seismic isolation device 14 are adjacent to each other. Bolts are passed through each of a plurality of holes provided in the upper flange plate 14b, and each insert included in the upper base plate 18 is provided. The PCa board 16 is firmly fixed to the seismic isolation device 14 by being screwed to the hardware 17 and installed.

  In step 340, a plurality of reinforcing bars constituting the column base portion of the upper structure, that is, each of the column main bars are screwed and fixed to each of the plurality of fixing portions 22 included in the reinforcing bar fixing member 21, and in step 350, The construction of this seismic isolation foundation is completed. Specifically, each pillar main bar is screwed into each fixing unit 22 and fixed. Thereby, the accuracy of the column main bar position can be improved, and the work of bar arrangement is saved. Further, since the PCa board 16 is used, it is not necessary to attach a formwork and cast concrete, and it is possible to realize labor saving of formwork.

  When the construction of the base isolation structure is completed as described above, the upper structure such as a building or a condominium can be constructed by a conventional construction method. When constructing the superstructure, it is possible to adopt the PCa method of construction using precast concrete material. Further, this method may include using a conveying device including a hooking portion, hooking the hooking portion on a hanging jig, and conveying the precast concrete board onto the seismic isolation device.

  So far, the construction method of the base isolation structure of the present invention and the base isolation structure constructed by the method have been described in detail with reference to the embodiments shown in the drawings. The present invention is not limited to the embodiments, and other embodiments, additions, changes, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. As long as the above is achieved, it is included in the scope of the present invention.

  Therefore, the connection between the lower foundation 15 and the seismic isolation device 14 and the connection between the seismic isolation device 14 and the PCa panel 16 are not limited to bolts, and may be connected by welding or the like. An anchor bar or the like may be embedded and fixed more firmly, or a reinforcing bar or the like embedded in order to increase the strength of the PCa board 16 may be employed.

DESCRIPTION OF SYMBOLS 10 ... Anchor bolt, 11 ... Floor slab, 12 ... Insert metal fitting, 13 ... Lower base plate, 14 ... Seismic isolation device, 14a ... Lower flange plate, 14b ... Upper flange plate, 14c ... Laminated rubber, 15 ... Lower foundation, 16 ... PCa board, 17 ... Insert metal, 18 ... Upper base plate, 19 ... Anchor bolt, 20 ... Insert metal, 21 ... Rebar fixing member, 22 ... Fixing part

Claims (4)

A method for constructing a base-isolated base structure,
Attaching a reinforcing bar fixing member provided at a predetermined position on the precast concrete board, each of which is disposed at a predetermined position and includes a plurality of fixing portions for screwing and fixing each reinforcing bar;
Installing the precast concrete board on a seismic isolation device;
And fixing each of the plurality of reinforcing bars constituting the column base portion of the superstructure by screwing to each of the plurality of fixing portions. The precast concrete board has a hanging jig,
2. The method according to claim 1, further comprising the step of transporting the precast concrete board onto the seismic isolation device by using a transport device having a hook portion, hooking the hook portion on the hanging jig, and transporting the precast concrete board onto the seismic isolation device. Method. A seismic isolation device;
A precast concrete board installed on the seismic isolation device;
Reinforcing bar fixing provided with a plurality of fixing portions attached on the precast concrete board, each of which is arranged at a predetermined position and screwing and fixing each of the plurality of reinforcing bars constituting the column base portion of the superstructure. Seismic isolation substructure including members.   The said precast concrete board is a seismic isolation foundation structure of Claim 3 provided with the jig | tool for a suspension for suspending and conveying on the said seismic isolation apparatus.