JPH09291542A - Reinforced base of column using u-shaped anchor bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the construction by forming a bolt hole of a base plate into a narrow and long bolt hole in parallel with the inside of a U-shaped surface of an anchor bolt so that the anchor bolt can be fitted even in the case where a top of the U-shaped anchor bolt is widened. SOLUTION: A bolt hole of base plate 3 is formed into a narrow and long bolt hole 4 in parallel with the inside of the U-shaped surface of an anchor bolt 2 so that the anchor bolt can be fitted even in the case where a top of the U-shaped anchor bolt 2 is widened. The anchor bolt 2 is embedded in the foundation concrete for crossing, and two sets of anchor bolts 2 are fitted in the bolt holes 4 of the base plate 3, and thereafter, each anchor bolt 2 and the base plate 3 are fixed by a nut 4, and a reinforced column 5 is stood in the foundation. Consequently, fixing withstanding force is improved, and since an interference with the beam arrangement of the foundation is reduced, workability in the construction field can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel column base when a steel structure is used for civil engineering / construction or a work.

[0002]

2. Description of the Related Art When a steel-framed column is erected on a reinforced concrete foundation, an anchor bolt 2A is embedded in the foundation concrete 1 and fitted into the anchor bolt 2A as shown in FIGS. A pillar 5 having a base plate 3 having a bolt hole 4A for inserting an anchor bolt at a predetermined position is erected, and the anchor bolt 2A and the base plate 3 are fixed with a nut 6. The base plate 3 is a steel plate or an assembly material thereof, and cast steel and die-forged steel products are also used.

[0003]

The column base not only supports the load of the upper frame, but also generates a bending moment and a shearing force on the column base during an earthquake or a windstorm. These stresses must be transmitted to the foundation by the base plate and anchor bolts. In order to satisfy this function, it is necessary that the anchor bolt fits into a pre-drilled hole in the base plate and is fixed by tightening it with a nut. Therefore, ensuring the installation accuracy of anchor bolts is an important point of construction management.

Since the anchor bolt bears a stress against a bending moment, it is arranged at a symmetrical position outside the cross section of the column. The number is designed according to the magnitude of stress, but the smaller the number is, the easier the quality control is. However, a minimum of four bolts are required, and in order for these bolts to have effective anchoring strength against tensile force, the U-shaped anchor bolt 2 formed by cold bending one steel rod is mechanically It has been experimentally verified that the efficiency is good. The most efficient arrangement is the four-bar type with the U-shaped bottoms crossed as shown in FIGS.

However, this U-shaped anchor bolt has residual stress in the bent portion, so it is processed in the factory, transported, and subjected to shocks during the installation process in the field.
As shown in FIG. 6, the top has a predetermined dimension L-1 to L-2.
Tends to open.

The size of the spread is difficult to predict and may not fit into the bolt holes formed in the base plate. In this case, there is a method of removing the concrete around the top of the bolt and heating the straightening of the top with a gas burner, etc., but this requires a lot of work and not only deteriorates the material of the bolt but also bends it locally. Since the tensile strength of anchor bolts is reduced, it is not generally accepted. In this case, there is a problem that it is unavoidable to take measures such as replacing the base plate with a wrong bolt arrangement.

The present invention has been made to solve the above-mentioned problems of the prior art. A U-shaped anchor bolt, which is mechanically efficient, is used as the anchor bolt, and it can be installed without any trouble even if the top portion of the anchor bolt expands. The purpose of the present invention is to provide a steel column base using a V-shaped anchor bolt.

[0008]

According to the present invention, an anchor bolt is embedded in a foundation concrete, and a column having a base plate having a bolt hole at a predetermined position so as to fit with the anchor bolt is erected. In a steel column post in which a steel column is erected on a foundation by fixing the anchor bolt and the base plate with a nut, the anchor bolt is a U-shaped anchor bolt, and the hole of the base plate is in a U-shaped plane of the anchor bolt. Parallel elongated bolt holes.

Further, according to the present invention, at least two sets of U-shaped anchor bolts are arranged in a taxi shape.

Further, according to the present invention, a four-bolt type in which two sets of U-shaped anchor bolts are arranged in a taxi shape.

Further, according to the present invention, an eight-bolt type in which four sets of U-shaped anchor bolts are arranged in a taxi shape.

Further, according to the present invention, the gap between the bolt shaft portion and the bolt hole of the base plate is filled with the filler.

According to the present invention, the filler is a high strength mortar.

Further, according to the present invention, the filling material is a resin material having an adhesive function.

The hole of the base plate is made into the U of the anchor bolt.
By making the elongated bolt holes parallel to each other in the V-shaped plane, it is easy to fit the deformation of the U-shaped anchor bolt that tends to open with time.

Further, in the normal use state, the shearing force is transmitted by the frictional force of the lower surface of the base plate against the shearing force. However, since the bolt hole is an elongated hole, the bolt shaft portion and the side surface of the hole are likely to come into contact with each other. The shearing force in either direction is transmitted to part or all of the bolt.

Further, by injecting a high-strength filler around the bolt hole and the bolt shaft portion, the rigidity of the joint portion between the base plate and the anchor bolt is strengthened, and a rigid column base is formed so that the anchor bolt has a shearing force. Will also be able to bear.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Since the U-shaped anchor bolt tends to spread outward as described above, when it is manufactured in a factory, it is bent to be narrower than the designed size, but the degree of deformation is difficult to predict. However, it is obvious that the deformation is on the line A connecting the opposing bolts 2 and 2 as shown in FIG.

Therefore, the bolt hole formed in the base plate 3 is not a round hole, but as shown in FIGS. 1 and 2, an elongated bolt hole parallel to the direction in which deformation is predicted, that is, in the U-shaped surface of the anchor bolt 2. 4 makes it easy to fit the top of the bolt.

FIG. 1 shows a line connecting the bolts 2 and 2 in which the holes of the base plate 3 are opposed to four bolt types in which two sets of U-shaped anchor bolts 2 are arranged in a taxi shape.
That is, the elongated bolt holes 4 are parallel to each other in the U-shaped surface. Further, FIG. 2 shows an example in which four sets of U-shaped anchor bolts 2 are applied to eight bolt types in which they are arranged in a taxi shape. In either case, the U-shaped anchor bolt can be easily fitted to the deformation of the U-shaped anchor bolt that tends to open with time.

Incidentally, it is customary to design the shearing force applied to the column base to be transmitted by the frictional force at the contact surface between the lower surface of the base plate and the basic concrete. A value of 0.4 is used as the friction coefficient at this time. When the shear force becomes large, or in a tower frame or a frame having a bracing, when the entire frame receives a horizontal force, the axial force of the column may become a tensile force instead of a compressive force. In particular, when the frame surface is provided with braces or earthquake resistant walls, the columns connected to these members are subjected to an alternating load of compressive force and tensile force due to seismic force. In the case of tensile force, since frictional force cannot be expected, the anchor bolt bears horizontal tensile force in the direction perpendicular to the axial tensile force. In this case, the elongated bolt hole and the bolt shaft portion can come into contact with each other against shearing force in any direction.

In order to make the shearing force transmission mechanism more reliable, as shown in FIG. 7, a high-strength mortar or a resin grout material having an adhesive function is provided in the gap between the bolt shaft portion 2a and the bolt hole 4 of the base plate. Such a filling material 7 is filled. As the filler, any organic material or inorganic material can be used. When filling this filling material, as shown in FIG. 8, as a nut loosening prevention, a recess 8 larger than the outer diameter of the nut 6 is used.
Is formed around the bolt hole 4 and the recess 8 is filled with the filling material 7, the rotation of the nut is restrained to prevent loosening.

Further, as shown in FIG. 9, when the anchor bolt 2 is tightened by the nut 6 from the upper and lower surfaces of the base plate 3, since the threaded portion 2b of the bolt is in the bolt hole 4, these are filled. The material 7 has a role of protecting the threaded portion and also of stiffening the defective cross section of the thread groove. 9 is a washer for stopping the filling material.

In the above example, the U-shaped anchor bolts are arranged in a taxi shape, but the present invention can be implemented even when the U-shaped anchor bolts are arranged in parallel.

[0025]

The U-shaped anchor bolt, which is an alternative to the conventional straight anchor bolt, has improved fixing strength. Further, since the U-shaped anchor bolt can have a small fixing depth, it does not interfere with the reinforcement of the foundation or the like, so that the workability at the construction site is improved and the cost is reduced as a whole. Then, by forming the holes of the base plate as elongated bolt holes parallel to the U-shaped surface of the anchor bolt, even if the top of the U-shaped anchor bolt expands, they can be fitted without any trouble. Further, since the base plate only needs to be changed in the drilling process, the function can be ensured without increasing the cost, and the workability is improved because it is not necessary to modify the table for correcting the positional accuracy of the bolt. Also, by using a high-strength filling material around the bolt holes and bolt shafts, the steel column base and the foundation are mechanically integrated, and the rigid column base structure ensures the safety of steel processing. It will be.

[Brief description of drawings]

FIG. 1 is a plan view in which the present invention is applied to a four-bolt type in which two sets of U-shaped anchor bolts are arranged in a taxi shape.

FIG. 2 is a plan view in which the present invention is applied to an eight-bolt type in which four sets of U-shaped anchor bolts are arranged in a taxi shape.

FIG. 3 is a front view showing a relationship between a U-shaped anchor bolt arranged in a taxi shape and a base plate.

FIG. 4 is a sectional view taken along the line II in FIG. 3;

FIG. 5 is a sectional view taken along the line 2-2 of FIG. 3;

FIG. 6 is a front view (upper part) and a plan view (lower part) showing a deformed state of the anchor bolt.

FIG. 7 is a plan view in which a high-strength filler is filled around the bolt hole and the bolt shaft portion.

FIG. 8 is a vertical cross-sectional view showing another mode in which a high-strength filler is filled.

FIG. 9 is a vertical sectional view showing still another embodiment in which a high-strength filler is filled.

FIG. 10 is a front view of a conventional steel column base.

11 is a sectional view taken along the line EE of FIG.

[Explanation of symbols]

 1 ... Foundation concrete 2 ... U-shaped anchor bolt 3 ... Base plate 4 ... Bolt hole 5 ... Steel column 6 ... Bolt 7 ... Filler 8 ... Recess 9 ...・ Filling material washer

Front page continuation (72) Inventor Kuniaki Sato 24-21 Yaesaki-cho, Hiratsuka-shi, Kanagawa (72) Inventor Atsushi Yamada 2-4 Toyo, Koto-ku, Tokyo Hitachi Koki Co., Ltd. (72) Inventor Takashi Kitano 1-9-1 Kitahama, Wakamatsu-ku, Kitakyushu-shi, Fukuoka Prefecture Inside the Wakamatsu Plant of Nitate Metal Co., Ltd.

Claims (7)

[Claims] 1. An anchor bolt is embedded in foundation concrete, a pillar having a base plate having a bolt hole at a predetermined position is erected to fit the anchor bolt, and the anchor bolt and the base plate are fixed with a nut. Thus, in the steel column base for standing the steel column on the foundation, the anchor bolt is a U-shaped anchor bolt, and the hole of the base plate is U of the anchor bolt.
Steel column pedestal using U-shaped anchor bolts, which are elongated bolt holes parallel to each other in the character plane. 2. A steel column base using a U-shaped anchor bolt according to claim 1, wherein at least two sets of U-shaped anchor bolts are arranged in a taxi shape. 3. The steel column pedestal using a U-shaped anchor bolt according to claim 2, which is a four-bolt type in which two sets of U-shaped anchor bolts are arranged in a taxi shape. 4. A steel column pedestal using a U-shaped anchor bolt according to claim 2, which is of an eight-bolt type in which four sets of U-shaped anchor bolts are arranged in a taxi shape. 5. The steel column base using a U-shaped anchor bolt according to claim 1, wherein a filler is filled in a gap between the bolt shaft portion and the bolt hole of the base plate. . 6. The steel column base using a U-shaped anchor bolt according to claim 5, wherein the filler is a high-strength mortar. 7. The steel column base using a U-shaped anchor bolt according to claim 5, wherein the filling material is a resin material having an adhesive function.