JPH05179657A - Fixing for leg of steel column - Google Patents

Abstract

PURPOSE:To attain a fixing method for legs of steel columns with a small number of PC cables and good workability without the need of high accuracy at the installation position of a PC cable. CONSTITUTION:A PC cable 14 is passed through the opening 17 in the perpendicular direction of a foundation 18, a column leg 11 is made to stand on the foundation 18 where the anchor fitting 14a of the PC cable 14 is embedded in concrete, and the upper part 14c of the PC cable is passed through a through hole in the stopper 12d of its foundation bed 12 Tensile force is given to the PC cable 14 by pulling its upper end, and a holding piece 12e is pushed into the through hole in the stopper 12d. By engagement, of the holding piece 12e with the through hole in the stopper 12d, the upper part 14c of the PC cable is held firmly to fix the foundation bed 12 of the column leg 11 to the foundation 18. Since the FC cable is used, it is possible to attain a larger diameter easily, eliminate the increasing number of the PC cable even when the diameter of the column leg is large, and reduce manufacturing cost and so forth of the foundation and the column leg.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fixing a column base of a steel column, and more particularly to a method of fixing a column base of a steel column to a foundation by using a PC cable for introducing prestress.

[0002]

2. Description of the Related Art A conventional column base 1 of a steel column is generally shown in FIG.
As shown in FIG. 7 and FIG. 7, the base 2 is fixed to the base 3 using anchor bolts 4c. That is, a plurality of rib pieces 2b are radially arranged on the upper surface of the quadrangular bottom plate 2a,
The lower end of each rib piece 2b is welded to the bottom plate 2a, and an octagonal support plate 2c is provided above the plurality of rib pieces 2b in parallel with the bottom plate 2a.
And the upper end of each rib piece 2b is welded to the support plate 2c to form the base 2. Square opening 2 of support plate 2c of base 2
c through the lower 1a of RHS Column _1, welded to the lower end portion 1a ₁ to the bottom plate 2a, and by welding a rim of the opening 2c ₁ of the support plate 2c on the peripheral surface 1a ₂ of RHS Column 1, A column base 1 of a prismatic steel column is formed. Further, a quadrangular bottom frame 4b is fixed to the lower end portion of the quadrangular tubular peripheral frame 4a, and the quadrangular bottom frame 4b
The lower ends of the anchor bolts 4c are fixed to a plurality of locations including the corners, and the upper ends 4 of the anchor bolts 4c are respectively fixed.
The anchor frame 4 is formed by projecting c ₁ from the upper end of the peripheral frame 4a. The anchor frame 4 is installed at a fixed position of the column base 1, the formwork 5 is arranged around the anchor frame 4, and concrete is placed in the formwork 5, and its upper surface 5a
A concrete foundation 5 is formed on which the upper end 3c ₁ of the anchor bolt 4c is projected. Then, the column base 1 is erected on the upper surface 5a of the base 5, and the bottom plate 2a and the support plate 2 of the base 2 are placed.
The bolt through hole formed in c is fitted to the upper end 4c ₁ of the anchor bolt 4c protruding from the upper surface 5a of the base 5, and the upper end 4c
A washer w is fitted to c ₁ and a nut n is screwed in to fix the column base 1 to the upper surface 5 a of the foundation 5.

[0003]

The anchor bolt 4 described above is to be solved.
To fix the column base 1 using c, the upper end 4c ₁ is fixed to the column base 1.
Since it is passed through the bolt through holes formed in the bottom plate 2a and the support plate 2c of the base 2 and fixed by using the nut n, high accuracy is required in the position where the anchor bolt 4c is arranged. Therefore, there is a drawback that an expensive anchor frame 4 must be used in order to secure the accurate position of the anchor bolt 4c. Further, since the anchor bolt 4c is made of PC steel rod, the maximum diameter of the commercially available anchor bolt 4c is 32 mm. Therefore, when the size of the column base 1 is large, it is necessary to increase the number of anchor bolts 4c. When the number of anchor bolts increases, the cost of manufacturing the base 2, the anchor frame 4, etc. increases, which causes an increase in the cost of fixing the column base 1. The problem to be solved by the present invention is to provide a method of fixing a column base of a steel column that does not have the drawbacks of the conventional fixing method using anchor bolts, in other words, high accuracy in the installation position of the PC cable. It is an object of the present invention to provide a method of fixing a column base of a steel frame column that does not require such a requirement and has a good workability that requires a small number of PC cables.

[0004]

The present invention adopts the following construction in order to solve the above-mentioned problems. According to the configuration of the present invention, the PC cable is passed through the plurality of vertical openings formed in the foundation, and the anchor metal fitting fixed to the lower portion of the PC cable is embedded in the concrete below the opening, The base of the steel column is erected on the foundation with the upper part of the base projecting above the base installation surface, and the tops of the PC cables are passed through the through holes of the multiple fasteners of the base of the base, respectively. The upper portion is projected from the upper surface of the stopper, the upper portion of the PC cable is pulled to give a tensile force, and the upper portion of the PC cable is fixed to the stopper by an appropriate fixing means to give the PC cable a tensile force. The method of fixing the column base of the steel column is characterized by maintaining the base of the column base and fixing it to the foundation. As the appropriate fixing means, for example, a gripping piece (wedge) is arranged around the upper portion of the PC cable passed through the through hole of the stopper.
The fixing means is used to press the gripping piece into the through hole of the stopper to firmly grip the upper portion of the PC cable.

In a preferred embodiment, as the PC cable, a PC stranded wire is cut into a predetermined length, and the P
Use the one with anchor metal fittings fixed to the lower end of the C stranded wire,
An unbonding process is applied to the portion of the PC cable located above the lower end of the sheath body described below. The unbond process is
Attach asphalt, resin, etc. to the surface of the PC stranded wire,
This is a treatment that prevents the PC strands from binding (adhering) with concrete, grout, mortar, etc. Then, erect the column base of the steel column, pass the upper part of the PC cable through the through hole of the stopper of the column base, and make a gap between the lower surface of the base of the column base and the upper surface of the foundation, and the vertical opening of the foundation. The gap between the inner peripheral surface and the outer peripheral surface of the PC cable is filled with grout, mortar, etc., and after the filled grout, mortar, etc. are hardened, the tensile force can be introduced into the PC cable. To do. In a preferred embodiment, a PC cable having an anchor metal fitting fixed to the lower end thereof is vertically arranged at a position corresponding to the corner of the base of the column base at the installation position of the column base, and the periphery of the PC cable is surrounded by a formwork or the like. And the sheath body is placed around the upper part of the PC cable, and concrete is placed in the formwork and between the formwork and the sheath body to form a concrete foundation. The lower PC cable part is embedded and fixed in the concrete of the foundation, the upper part of the PC cable above the lower part of the sheath can be freely bent, and the base of the flat column base is installed on the upper part of the sheath. Forming a face,
The upper portion of the PC cable is projected above the installation surface. As the column base of the steel column, for example, a base is fixed to the lower end of the steel column, and a stopper is fixed to a part of the base corresponding to a corner of the steel column. As the stopper, a vertical through hole for passing the upper portion of the PC cable is used, and in a preferred embodiment, a plurality of gripping pieces (wedges) arranged around the upper portion of the PC cable are stopped. The upper part of the PC cable can be firmly gripped by pushing it into the conical through hole of the tool.

[0006]

[Operation] The fixing method of the present invention is that the column base is erected on the foundation, the lower part is embedded in concrete, and the upper part of the PC cable is passed through the vertical opening, Through the through holes of the stoppers of the base plate, projecting their upper parts from the upper surface of the stoppers, pulling the upper parts of the PC cables to give a tensile force, and by an appropriate fixing means,
Since the upper part of the PC cable is fixed to the stopper, the tension applied state of the PC cable is maintained, and the base of the column base is fixed to the foundation, the part of the lower part of the PC cable embedded in concrete and the column base are Even if the through hole of the board stopper does not match correctly and there is an error in accuracy, the upper part of the PC cable is passed through the vertical opening and can be bent freely, The upper part of the PC cable can be easily passed through the through hole of the stopper of the board.

[0007]

[Embodiment] The base 12 of the column base 11 of the square steel pipe column of the first embodiment.
Is a square bottom plate 12a as shown in FIGS.
9 rib pieces 12b are radially arranged on the upper surface of each of the ribs, the lower end of each rib piece 12b is welded to the bottom plate 12a, and each rib piece 12b is arranged on a rectangular support plate 12c on the upper side of the rib piece 12b in parallel with the bottom plate 12a. The upper ends of the rib pieces 12b are welded to the support plate 12c. The PC cable 1 is provided at the four corners of the bottom plate 12a.
4 is formed with a through hole 12a ₁ , and the support plate 12
Openings 12c ₁ are formed at the four corners of c at positions corresponding to the through holes 12a ₁ . Each of these in the opening 12c ₁ fitted is stop 12d, and is fixed by welding or the like. Each stop 12d Yes through hole 12d ₁ conical is formed, the through holes 12d ₁
A 40% gripping piece (wedge piece) 12e for gripping the PC cable 14 that has passed through the hole 12d ₁ is fitted therein. The gripping piece 12e has a shape in which a frustoconical body having a through hole in the center is divided into four parts.
By enclosing the C cable 14 and pushing each gripping piece 12e into the conical through hole 12d ₁ of the stopper 12d in a state where a tensile force is applied to the PC cable 14, the PC cable 14 can be gripped. is there. The lower 11a of quadrangular corner steel column to the opening 12c ₂ of the support plate 12c of the base 12 is passed, its lower end surface 11a ₁ are welded to the bottom plate 12a of the base 12, and square openings of the support plate 12b 1
The edge of 2b ₁ is fixed to the peripheral surface 11a ₂ of the square steel pipe column by welding to form the column base 11 of the square steel column. Pedestal 11
As for the PC cable 14 used for fixing, the PC stranded wire is cut into a predetermined length, the anchor metal fitting 14b is fixed to the lower end of the PC stranded wire 4a, and the PC cable located above the lower end of the sheath body 17 described later. It is made by unbonding the part.

The PC cable 14 is vertically arranged at a position substantially corresponding to the position of the stopper 12d of the bottom plate 12a of the base 12 on the discarded concrete or the like at the installation position of the column base 11, and the PC cable 14 is surrounded. Form 15 and form 1
A top plate 16 made of metal is attached to the upper part of 5. This top plate 1
6, a large-diameter opening 16a is formed at a position corresponding to the through hole 12a ₁ of the bottom plate 12a.
The sheath body 17 is arranged on the lower side of a. And the opening 16
a through the PC cable 14 and the PC
With the cable 14 stretched in the vertical direction, the top plate 16
Concrete is placed in the formwork 15 at the bottom of the
8 is formed. The portion of the PC cable 14 below the lower portion of the sheath body 17 is embedded and fixed in the concrete of the foundation, and the portion of the PC cable 14 above the lower portion of the sheath body 17 is freely bent in the sheath body 17. I'm ready to get On the top plate 16 of the foundation 18, via an appropriate spacing member, making a pedestal 11, through the bottom plate 12a of the base 12 holes 12a ₁ and the through hole 12d of the conical stopper 12d of the support plate 12c ₁ through top 14c of the PC cable 14, to protrude the upper end 14c of the upper surface of the stopper 12d. The gripping piece 12e divided into four around the upper portion 14c of the PC cable 14 is provided with the conical through hole 1 of the stopper 12d.
Fit to 2d ₁ . And the bottom plate 1 of the column base 12
A gap between the lower surface of 2a and the upper surface of the top plate 16 of the foundation 18,
Grout, mortar, or the like is filled in a gap or the like between the inner peripheral surface of the sheath body and the outer peripheral surface of the PC cable.

In a state where the grout, mortar, etc. filled in the gap are hardened, the upper end portion 14c ₁ of the PC cable 14 is gripped and pulled by the gripping tool of the jack, and a tensile force is applied to the PC cable 14. In the state in which the tensile force is applied to the PC cable 14, the gripping piece 12e is divided into four pieces.
Is pushed into the conical through hole 12d _{1 of the} stopper 12d, and the upper portion 14c of the PC cable 14 is firmly gripped by fitting the four-piece gripping piece 12e and the stopper 12d.
Then, the tension applied state of the PC cable 14 (that is, the prestressed state) is fixed. PC cable 14
Section and column base embedded in concrete underneath
Even if the through holes 12a _{1 and the} like of the base 12 do not exactly coincide with _each other and there is an error in accuracy, the upper portion 14c of the PC cable 14 is placed in the large opening 16a of the top plate 16 and the sheath body 17. Since the portion of the PC cable 14 above the lower portion of the sheath body 17 is freely bendable, the upper portion 14c of the PC cable 14 is inserted into the through hole 12a ₁ of the base 12 and the through hole of the stopper 12d. It can be easily threaded through 12d ₁ . Also, the through hole 12a ₁ and the through hole 1
Since the top 14c of the PC cable 14 through the 2d ₁ is gripped by the fitting between the through holes 12d ₁ of the four split gripping piece 12e and stop 12d, an error on the accuracy will not be at all a problem ..

The base 22 of the column base 21 of the square steel pipe column of the second embodiment
As shown in FIGS. 4 and 5, the base plate 22 is formed of a square steel plate, and through holes 22a are formed in the four corners of the base 22, and the stoppers 22 are formed in the through holes 22a.
The protrusion at the lower end of b is fitted and each stopper 22b is fixed to the substrate 22 by welding or the like. Each stop 22b Yes through hole 22b ₁ conical is formed, the through-holes 2
2b the _first upper one PC cable through the hole 22b ₁
A 40% gripping piece 22c for gripping 4c is fitted. The gripping piece 22c is a truncated cone with a through hole in the center.
It has a split shape, and the gripping piece 22 is divided into four pieces.
Surround the upper part 14c of the PC cable with c
In a state where the tensile force was applied to 4, by pushing the through hole 22b ₁ conical stopper 22b each gripping pieces 22c, so that the can grip the top 14c of the PC cable 14. Then, the lower end surface of the lower portion 21a of the square steel pipe column is applied to the center portion of the base 22, the lower end portion is welded to the base 22, and the lower portion 21a of the square steel pipe column on the upper surface of the base 22.
Nine rib pieces 22d are radially arranged around the circumference of each of the ribs, the lower ends of the rib pieces 22d are welded to the base 22, and the vertical edges of the rib pieces 22d are welded to the peripheral surface 21b of the lower portion 21a of the square steel pipe column by welding. The column bases 21 of the square steel pipe columns are fixedly formed. The method of fixing the column base 21 of the square steel tube column to the foundation 18 is the same as that in the first embodiment, and the description thereof will be omitted.

[0011]

The present invention has the following effects (a) to (h) by having the structure described in the section of the claims. (A) According to the first and second aspects, the position of the portion of the PC cable embedded in the concrete under the concrete and the position of the stopper of the base of the pedestal do not exactly match, and there is an error in accuracy. Even though there is, the upper part of the PC cable is inserted into the vertical opening of the foundation and is ready to be bent, so that the upper portion of the PC cable can be easily inserted into the through hole of the stopper of the base. Can be threaded. (B) According to the third aspect, the work of introducing the tensile force into the PC cable is facilitated, there is no fear that the fixing between the base of the column base and the foundation will be loosened, and the PC cable in this portion is corroded. There is nothing to do. (C) According to claim 4, the anchor metal fitting fixed to the lower portion of the PC cable is embedded in the concrete of the foundation, and the upper portion of the PC cable is passed through the vertical opening of the foundation, so that the PC cable is It is possible to easily form a concrete foundation in which the upper part of the base projects from the installation surface of the column base. (D) According to the fifth aspect, the column base can be formed only by fixing the stopper having the through hole in the vertical direction at the position of the base corresponding to the corner of the steel frame column. Since the position of the through-hole is not required to have high accuracy like the bolt through-hole, the column base of the steel frame column can be provided at low cost. (G) According to the fixing method of the present invention, since a PC cable is used, a large diameter one can be easily manufactured by using a commercially available PC twisted wire, and even if the column base has a large dimension, P
It is not necessary to increase the number of C cables, and the increase in the number of PC cables can be suppressed. Therefore, the manufacturing cost of the foundation, the base of the column base, and the like can be reduced, and the cost for fixing the column base can be reduced. (H) According to the fixing method of the present invention, since an expensive anchor frame is not used, the PC cable having the anchor metal fitting fixed to the lower end can be arranged after the reinforcing bar of the concrete foundation is arranged, and the workability is improved. In addition, the fixing method of the present invention does not require high accuracy in the installation position of the PC cables and can minimize the number of PC cables, so that workability can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing a fixed state and the like of a column base of Example 1.

FIG. 2 is a plan view of the base of the column base shown in FIG.

FIG. 3 is a front view of a gripping means on an upper portion of the PC cable shown in FIG.

FIG. 4 is a plan view of the base of the column base of the second embodiment.

5 is a front view of the gripping means on the upper portion of the PC cable shown in FIG.

FIG. 6 is a front view showing a column base or the like fixed by a conventional fixing method using anchor bolts.

FIG. 7 is a plan view of the base of the column base shown in FIG.

[Explanation of symbols]

11 Column Base 12 Base 12a Bottom Plate 12b Rib Piece 12c Support Plate 12d Stopper 12d ₁ Through Hole 12e Gripping Piece 14 PC Cable 14b Anchor Metal Fitting 14c PC Cable Upper 15 Form 16 Top Plate 16a Open 17 Sheath 18 Concrete Foundation 19 Grout, mortar, etc. 21 Column base 22 Base 22b Stopper 22b ₁ Through hole 22c Grasping piece 22d Rib piece

Claims (6)

[Claims] 1. A PC cable is passed through a plurality of vertical openings formed in a foundation, and anchor metal fittings fixed to the lower portion of the PC cable are embedded in concrete below the openings to form the PC cable. The column base of the steel column is erected on the foundation whose upper part is projected above the base installation surface, and the upper parts of the PC cables are passed through the through holes of the plurality of fasteners of the base of the column base, respectively The upper part of the PC cable by pulling the upper part of the PC cable to pull the upper part of the PC cable and applying a tensile force to the PC cable with an appropriate fixing means. A method for fixing the column base of a steel column, which is characterized by maintaining and fixing the base of the column base to the foundation. 2. A PC cable is passed through a plurality of vertical openings of a concrete foundation, and anchor metal fittings fixed to the lower portion of the PC cable are embedded in concrete below the opening, and the upper portion of the PC cable. Stand up the base of the steel column on the foundation protruding above the base installation surface, pass the tops of the PC cables through the through holes of the plurality of stoppers of the base of the base, and attach the tops of them. The gripping piece projecting from the upper surface of the PC cable and arranged around the upper part of the PC cable is fitted into the through hole of the stopper, and the PC cable is pulled at the upper part to give a tensile force to the gripping piece. The column base of the steel frame column is characterized in that the upper part of the PC cable is firmly gripped by being pushed into the through hole of the PC and the gripping piece and the stopper are fitted to fix the applied state of the tensile force of the PC cable. Fixing method. 3. A PC cable having unbonded portions located above the lower end of the vertical opening of the foundation is used, and the gap between the lower surface of the column base and the upper surface of the foundation, the foundation The gap between the inner peripheral surface of the vertical opening of the PC cable and the outer peripheral surface of the PC cable is filled with grout, mortar, etc., and the filled grout, mortar, etc. is cured, and then the tensile force to the PC cable is increased. The method of fixing a column base of a steel column according to claim 1 or 2, wherein the method is performed. 4. A PC cable having an anchor metal fitting fixed to the lower end thereof is arranged vertically at a position corresponding to a corner of the base of the column base at the installation position of the column base, and the periphery of the PC cable is surrounded by a formwork or the like. A sheath is placed around the upper part of the PC cable, and the foundation is formed by placing concrete in the form and between the form and the sheath to form a foundation. The PC cable is embedded and fixed in the concrete of the foundation, the PC cable above the lower part of the sheath is freely bendable, and the installation surface of the base of the flat column base is formed on the upper part of the sheath. A method of forming a column base fixing base, characterized in that the upper part of the cable is projected above the installation surface. 5. A base is fixed to the lower end of the steel column, and a stopper is fixed to a portion of the base corresponding to the corner of the column, and a vertical through hole for passing the upper portion of the PC cable is formed in the stopper. The column base of the steel column is characterized in that the upper part of the PC cable can be firmly gripped by pushing the gripping piece arranged around the upper part of the PC cable into the through hole of the stopper. .. 6. A PC cable in which an anchor metal fitting is fixed to the lower end of the base of the pillar base at the position where the pillar base is installed and an unbonded upper part is subjected to an unbonding treatment in the vertical direction. , Form the frame around the PC cable, attach the metal top plate to the top of the form, and the sheath below the opening made at the position of the top plate that corresponds to the stopper of the base. , The PC cable arranged in the vertical direction is passed through the opening and the sheath body, and concrete is placed in the formwork below the top plate to form a concrete foundation. From the bottom of the sheath body, Also, the lower portion of the PC cable is embedded in concrete, and the portion of the PC cable above the lower portion of the sheath body can be freely bent, and on the top plate of the foundation,
Through a proper spacing member, stand the column base of the steel frame column, pass the upper part of the PC cable through the through hole of the stopper of its base,
The upper end is projected from the upper surface of the stopper, and a plurality of gripping pieces are arranged around the upper part of the PC cable, the gap between the bottom surface of the base and the top plate of the base, and the inner peripheral surface of the sheath body. The space between the outer peripheral surface of the PC cable is filled with grout, mortar, etc., and the filled grout, mortar, etc. is hardened, and then the upper portion of the PC cable is pulled to give a tensile force, The split gripping piece is pushed into the conical through hole of the stopper, and the upper part of the PC cable is firmly gripped by fitting the gripping piece and the stopper so that the tension of the PC cable is applied. A method of fixing the column base of a steel column, which is characterized by fixing and fixing the base of the column base to the foundation.