JPH0670326B2 - How to set up a PC pillar on the foundation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a PC pillar erecting method for erecting a precast concrete pillar (hereinafter referred to as a PC pillar) on a foundation when constructing a multi-story structure.

(Prior Art) Generally, in building a multi-story structure such as a building using PC columns, PC columns having a height of about 3 floors are manufactured in advance,
This is to be erected on a cast-in-place concrete foundation. As shown in FIG. 3, the conventional erection method is that a pillar insertion hole 2 is opened on the upper surface of a concrete foundation 1, a PC pillar 3 is erected and dropped into the hole, and a supporting wire 4 from four sides is used. After adjusting the verticality, a wedge 5 is driven into the opening of the column fitting hole 2 to temporarily fix it, and then, a gap 6 in the column fitting recess 2 is filled with a filler 6 such as cement mortar or concrete. PC pillar 3 by solidifying
And the foundation 1 are integrated. in this case,
When the depth of the column fitting hole 2 is 1.5 times or more the diameter of the PC column 3, a rigid connection is established.

In addition, as shown in FIG. 4, one end side of the PC steel rod 10 is embedded and fixed in the concrete foundation 1 cast in situ, and the other end is projected onto the foundation 1, and the PC pillar 3 is provided with PC. Steel rod
11 is inserted in the longitudinal direction, and the lower end thereof is made to project into the recess 12 of the lower end surface of the PC column 3, and this PC column 3 is laid with a mortar 13
The vertical degree is adjusted by the support wire 4 standing on the upper surface of the foundation 1 via the PC steel rod of the foundation 1 and the PC pillar 3,
1 is connected with the coupler 14 in the recess 12 and the PC steel bar 11
Is fixed at the upper end of the PC pillar 3 to be self-sustaining while introducing a vertical prestress to the PC pillar 3, and the recess 12 is filled with post-mortar.

(Problems to be solved by the invention) In the above-mentioned conventional methods, in any case, the verticality when the PC pillar is erected is adjusted by adjusting the length of the supporting wire around it. The heavier the PC column becomes, the more difficult it is to adjust the verticality, and it takes a long time to stand on its own, and during this time, long support wires are stretched diagonally around the PC column. Therefore, there is a problem that the work efficiency is poor because it becomes an obstacle to other work.

In addition, in the method of providing a column insertion hole in the foundation described above, it is necessary to increase the strength of the basic concrete around the hole, but since it is an in-situ construction, it becomes difficult to manage for strength development, In addition, since the pillar fitting hole is deep, it is difficult to accurately finish the levelness of the bottom surface of the hole.

Furthermore, the above-mentioned method of self-supporting with the PC steel rod requires tension work at the upper end of the long PC pillar before self-supporting at the site, which poses a high risk of work, and the lower end of the PC pillar has PC
Since there is a recessed portion for the work space for connecting steel rods, this causes a cross-section loss of the column, and there is a problem that the entire column needs to be thickened to compensate for this.

The present invention has been made to solve various problems of the conventional method as described above.

(Means for Achieving the Problem) The gist of the present invention for solving the above-mentioned conventional problems is that the outer peripheral surface of the lower end is integrally provided with an overhanging portion, and the overhanging portion vertically extends. Using a precast concrete column (hereinafter referred to as PC column) whose anchor steel rod insertion hole is opened through and the bottom surface is finished at a right angle to the column axis,
When constructing a concrete foundation in which the PC columns are erected, form a concave portion into which the lower end of the PC column is inserted on the upper surface of the foundation, and the upper end of the anchor steel rod for fixing the PC column from the bottom surface of the concave portion. Sides are projected, and mortar is laid on the bottom surface of the recessed portion, and a pedestal block having a flat upper surface is placed on the mortar so that the upper surface of the pedestal block is horizontal, and waiting for the mortar to solidify. The PC column is erected on its upper surface, the anchor steel rod protruding from the bottom surface of the recess is inserted into the anchor steel rod insertion hole of the overhanging portion, and the anchor steel rod is placed on the upper surface side of the overhanging portion. There is a method of standing a PC column on a foundation characterized in that the PC column is self-sustained by being tensioned and the PC column becomes self-supporting, and then the cast-in-place concrete is placed in the recessed part and the lower end of the PC column is embedded in the concrete foundation. .

(Operation) In the method of the present invention, by adjusting the levelness of the upper surface of the pedestal block on the spread mortar before solidification, the solidification of the spread mortar causes the pedestal block to be in a state where the upper surface becomes horizontal and fixed in the recessed portion. To be done. Then, by joining the bottom surface of the PC pillar to the upper surface of the pedestal block, the PC pillar is erected vertically and other vertical adjustment work is unnecessary.

In this state, by anchoring the upper end of the anchor steel rod penetrated by the anchor insertion hole of the overhanging portion, the PC column becomes self-supporting without the need for a supporting wire.

Furthermore, even after the lower end of the PC column is buried in the foundation by cast-in-place concrete, the horizontal external force applied to the PC column is received by the anchor steel rod, and the shear force does not act on the basic concrete portion around the recess.

(Embodiment) Next, an embodiment of the present invention will be described with reference to FIG. 1 and FIG.

FIG. 1 shows a standing structure of PC columns for a foundation constructed according to the present invention.

In the figure, 21 is a concrete foundation and 22 is a PC column. The concrete foundation 21 is constructed by being integrated with the upper end of the foundation pile 23, and the recessed portion 24 for setting up the column is formed on the upper surface thereof.
Is molded.

A plurality of anchor steel rods 26 are provided on the bottom surface of the recess 24 so as to project therefrom. The anchor steel rod 26 has a lower end to which a fixing member 27 is fixed and is embedded in the basic concrete, and the upper end side is projected upward.

The PC pillars 22 are molded in advance in concrete pillar manufacturing yard in a factory or the like, and if necessary, those having a length of 1 to 3 floors are used.

The bottom surface of the PC pillar 22 is finished at right angles to the pillar axis, and a pair of overhanging portions 28 are integrally formed on both sides of the lower end of the pillar 22 in a symmetrical arrangement with respect to each other. An anchor steel rod insertion hole 29 facing toward is opened.

When the PC pillar 22 is erected, first, the mortar 30 is laid on the bottom surface of the recessed portion 24 to a thickness of about 2 to 3 cm, and the pedestal block 31 is placed on the mortar 30.

The pedestal block 31 is a precast concrete product in which a steel rod insertion hole 32 is formed in advance by penetrating vertically and at least the upper surface is formed flat, and the anchor steel rod 26 is penetrated vertically and laid on the mortar 30. Place it.
After that, adjust the tilt so that the upper surface is horizontal.

After the pedestal block 31 is installed in this way, the PC pillar 22 is set up after waiting for the mortar to solidify. At the time of the upsetting, the PC column 22 is lifted vertically, the anchor steel rod 26 is inserted into the hole 29, the lower end is dropped into the recess 24, and the lower end surface is joined to the pedestal block 31. Then, the fixing plate and the nut 33 are fitted on the upper end of the anchor steel rod 26 to fix the tension. This allows the PC columns 22 to stand vertically on the foundation 21. An adhesive (zero joint) is interposed between the upper end surface of the pedestal block 31 and the lower end surface of the PC column 22.

After making the PC column 22 self-supporting in this way, in-situ pouring concrete 34 is placed in the gap in the recessed part 24, and the overhanging part at the lower end of the PC column is placed.
Embed 28 in foundation 21.

(Effect of the invention) As described above, in the method of the present invention, since the PC column is fixed to the concrete foundation by the anchor steel rod, sufficient bonding can be obtained without deepening the recessed portion of the foundation,
In addition, it is not necessary to make the concrete around the recesses particularly strong, and since the anchor steel rod is penetrated into the overhanging part on the outer periphery of the lower end of the PC column to fix it, the fixing work is safe and , Will be easy.

Furthermore, in the present invention, a pedestal block is installed on the bottom surface of the recess,
By accurately adjusting the horizontalness of the upper surface, the required verticality of the PC pillar can be obtained, and the work of adjusting the verticality of the PC pillar on the site is unnecessary, and the support wire is also unnecessary, so that the work site can be widely used. It has the effect of being usable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a joint portion between a PC column and a foundation erected according to the present invention, FIG. 2 is a plan view of the joint portion before cast-in-place concrete, FIG. 3, and FIG. FIG. 4 is a cross-sectional view of each of the conventional examples. 21 …… Concrete foundation, 22 …… PC column, 23 …… Foundation pile, 24 …… Concave part, 26 …… Anchor steel rod, 27 …… Fixing metal fitting, 28 …… Overhang part, 29,32 …… Anchor Steel rod insertion hole, 30 …… laying mortar, 31 …… pedestal block, 33 …… nut, 34 …… cast-in-place concrete.

Claims (1)

[Claims] 1. An outer peripheral surface of a lower end is integrally provided with an overhanging portion, and an anchor steel rod insertion hole is vertically opened through the overhanging portion.
Also, using a precast concrete column (hereinafter referred to as PC column) whose bottom surface is finished at right angles to the column axis,
When constructing a concrete foundation in which columns are erected, form a recessed portion into which the lower end of the PC column is inserted on the upper surface of the foundation,
The upper end side of the anchor steel rod for fixing the PC column is projected from the bottom surface of the recessed portion, the mortar is laid on the bottom surface of the recessed portion, and the pedestal block having a flat upper surface is formed on the mortar. Is installed so that it is horizontal, the PC pillar is erected on its upper surface after solidification of the spread mortar, the anchor steel rod insertion hole of the overhanging portion, the anchor steel protruding from the bottom of the recessed portion. Insert the rod, the anchor steel rod is tensioned and fixed on the upper surface side of the overhanging part to make the PC column self-supporting, and then cast in-situ concrete in the recessed part, the lower end of the PC column is placed in the concrete foundation A method of standing a PC pillar on a foundation characterized by embedding.