JPH04247123A - Exposed type pedestal for structure of civil engineering construction - Google Patents

Abstract

PURPOSE:To absorb horizontal left and right errors between pedestales and errors in the length of beams jointed to each other when stress loaded on the pedestal is sufficiently born and used for an intermediate pillar or the like. CONSTITUTION:A pedestal 2 having a bag portion 2a on the bottom is placed opposedly to a foundation part 1. An anchor reinforcement 6 is inserted through the bottom of the pedestal 2 and foundation part 1 so that the relative position of both parts can be adjusted. A filler 8 such as concrete is filled between the bag portion 2a of the pedestal 2 bottom and/or pedestal bottom and the foundation part 1. The relative distance between the pedestal 2 bottom and foundation part 1 can be adjusted by the action of the anchor reinforcement 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a column base structure used when building a steel column for a civil engineering building structure on a concrete foundation, and more particularly to an improvement in an exposed type column base.

0002

[Prior Art] Column bases such as intermediate columns and side columns applied to civil engineering and architectural structures (hereinafter simply referred to as structures) are used when anchoring steel columns of steel structures on concrete foundations. However, the column base must have a function that allows the stress acting on the column base to be smoothly transmitted to the ground through the foundation concrete. It is necessary to select the column base structure taking into consideration the This type of column base structure currently proposed is:
There are three types: ■Exposed type column base, ■Neck wrap type column base, and ■Recessed type column base.

[0003] The structure of the exposed column base is as shown in a, b, and c in Fig. 3.
, d, and e, the column base 2 is exposed and the stress of the column base is transmitted to the foundation 1 by the anchor plate 5 and anchor reinforcement 6. However, in examples a, b, and c of the same figure, The degree of fixation (rigidity) varies considerably depending on the stiffening method.

Example d in the figure is a structure example in which the bottom end of the column pedestal 2 has a pin joint structure (hereinafter referred to as a pin column pedestal).
Example e in the figure has a structure in which the column base is assumed to be a pin, and the anchor reinforcement 6 is designed to have low bending resistance.

[0005] As shown in Fig. 4A, the root wrap-type column base is an example of a structure in which the bottom of the column base 2 is covered with reinforced concrete within the foundation 1. The problem is how to communicate and to what extent.

[0006] The embedded type column pedestal is an example of a structure in which the bottom part of the column pedestal 2 is embedded in one part of the foundation, as shown in FIG. 4B.

[0007] The types of column bases are as described above, but when classifying the various types of column bases from the aspect of fixation (rigidity), they are generally (
These are classified into a) fixed column base, (b) semi-fixed column base, and (c) column base pin, but these are classified into anchor plates 5.
The relationship between the rotation angle θ and the moment M of the column base 2 is expressed as shown in the graph of FIG. As can be seen from the graph in FIG. 5, (c) the column pedestal pin has a bending rigidity of 0, and in the case of complete fixation, the rotation angle of the column pedestal is 0 regardless of the column pedestal moment. However, in general, what is distributed between the column pedestal pin and completely fixed is called (b) semi-fixed column pedestal.

[0008] This (b) semi-fixed column base has a wide range, and as shown in the graph of Fig. 5, the straight line indicates the case where the tightening force of the anchor reinforcement of the exposed type column base and the rigidity of the anchor plate are small. On the other hand, what is shown as a broken line corresponds to a case where the tightening force of the anchor reinforcement and the rigidity of the anchor plate are large, and the bending point is the case where the anchor plate separates from the foundation due to the external force and column. This is the value of the leg rotation angle.

[0009] As described above, in the case where the column base is semi-fixed, the tightening force of the anchor bar, the size of the anchor bar, and the rigidity of the anchor plate greatly affect the degree of fixation (rigidity) of the column base. In addition, regarding the rotation of the column base of a root wrap type column base or an embedded type column base, there is a balance of forces, so the bending moment M
However, it acts depending on the embedded length of the column base and its rigidity, and the degree of fixation is distributed between completely fixed and semi-fixed. Although the evaluation method for the rotational rigidity of column bases cannot be uniformly handled, the deformation factors of column bases when the column base is semi-fixed are deformation of the anchor plate (bending strength), anchor reinforcement, etc. elongation (tensile strength), deformation due to concrete compression (compressive strength), rotation due to defects in base mortar, etc.

The column base semi-fixed (exposed type) type is applied to various structures, examples of which include the example e in FIG. 3 and the structure shown in FIG. 6. The column base 2 shown in the same figure has a pin column base structure, and its specific structure is as follows:
The structure is such that an anchor plate 5 is disposed on top, a column base 2 is installed on this, and an anchor bar 4 is passed through the anchor plate 5. Conventionally, the above-mentioned examples exist as column bases applied to structures.

[0011]

[Problem to be solved by the invention] Semi-fixed column base (exposed type)
Column bases are sometimes applied to relatively light structures such as factories, offices, and simple parking lots, but with this semi-fixed (exposed) type column base, the column bases, The joint between the steel frame and the foundation is a joint between dissimilar materials such as steel and concrete, and there have been many cases where damage has occurred due to poor construction.

[0012] In other words, in terms of construction, this problem arises from problems such as resetting the anchor bars, insufficient filling of mortar under the foundation, variations in the tightening of the anchor bars, and inaccurate positioning of the neck-wrapped reinforcing bars. In the case of exposed column bases,
Even if it is analyzed as a column base pin, it actually has a certain degree of fixation, and the applied stress can cause anchor bars to break, anchor plates to deform, concrete to be crushed where anchor bars are embedded in the foundation, etc. is occurring.

[0013] For example, there have been reports of cases in which anchor reinforcements have fallen out, but this is an example of concrete collapse due to inadequate design of the standing concrete section directly below the anchor plate. As mentioned above, the conventional column base structure includes the problems described above.

[0014] The present invention was invented in view of the above-mentioned points of view, and its purpose is to ensure that the stress applied to the column base is sufficient, and that the intermediate column etc. Column base structure that allows easy adjustment of level and horizontal movement when used in large numbers, especially semi-fixed type (exposed type) column base suitable for absorbing precision when using tension bolt connections for steel frame joints. The purpose is to provide a pillar base.

[0015]

[Means for Solving the Problems] The present invention provides a column pedestal structure for achieving the above-mentioned object, in which column pedestals whose bottom portions are bag portions face a foundation, and the bottom portions of these column pedestals and An anchor reinforcement is inserted between the base and the base so that the relative position of both can be adjusted, and concrete or the like is inserted between the bag of the base of the column and/or between the base of the base and the base. In order to increase the rotational capacity of the pin pedestal method and the filling material is loaded,
This structure employs a structure in which the bending resistance of the anchor bars is reduced by unbonding the anchor bars at the top of the foundation or the top and the bottom of the column pedestal.

[0016]

[Operation] The present invention adopts the above-mentioned configuration as the column base structure of the structure, but there are three types of column bases: ■ Exposed type column base, ■ Root wrap type column base, and ■ Recessed type column base. The target is semi-fixed column bases (exposed type), which are said to be relatively prone to damage among the types.

Column pedestal Semi-fixed type pedestal, for example, pin column pedestal (
As is well known, the hinge is a column base that transmits axial force and shear force, but does not transmit a bending moment in calculations, and from the perspective of its form, it is an exposed type column base. This pin pedestal requires horizontal bearing capacity and rotational force at the bottom of the foundation or at the anchor plate position.

The purpose of installing the unbonded portion is to improve the deformability of the anchor bar base or the base and the lower part of the anchor bar. In addition, when this column base is applied to the column base of a relatively light structure such as a factory or office, it can be expected to improve the rigidity and safety of the column base, and it is also easy to install. Easy and reliable.

[0019]

[Embodiment] Hereinafter, an embodiment of the column base structure of the present invention will be described in detail with reference to FIG. This embodiment is an example that can be applied to any of the pillar bases of intermediate pillars and side pillars of structures such as factories, offices, and simple parking lots.

The overall structure of the structure is not shown in the drawings, but as a general example, a plurality of concrete foundations (hereinafter simply referred to as foundations) are installed on land whose surface is leveled substantially. They are installed at predetermined positions, column bases are constructed on these foundations, and beam members are constructed between the upper parts of these column bases. Next, the entire structure is constructed by installing a floor plate over the entire area.

The construction (construction process) order of this column pedestal structure and the column pedestals and foundation are constructed as shown in the schematic cross-sectional views A, B, and C of FIG. 1.

That is, first, as shown in FIG. 1A, an unbonded part 7 for inserting the anchor reinforcement 6 described above is drilled in the foundation 1 arranged inside, and a pair of upper and lower parts are inserted into this unbonded part 7. Two anchor bars 6 with nuts 6a attached are inserted and fixed by pouring concrete, and the column base 2 is screwed into the anchor bars 6 as shown in FIG. 1B.

The column pedestal 2 uses a hollow prismatic column (a structure in which a joint plate is bonded to an H-shaped steel) whose bottom is formed as a bag portion 2a, and as shown in the figure, the inner and outer portions of the bag portion 2a of the column pedestal 2 are A pair of nuts 6a are screwed onto both sides of.

The column base 2 is constructed as described above.
As mentioned above, the foundation 1 is set to be generally horizontal, but the height levels of the column bases 2 may differ from each other. In this case, the level of the column base 2 is adjusted by operating the upper and lower nuts 6a, 6a.

When the level adjustment of the column base 2 is completed, concrete is poured into the column base 2 and fixed. Moreover, mortar or concrete 8 as a filler is loaded and fixed between the bottom of the column base 2 and the foundation 1 (see FIG. 1C).

The schematic cross-sectional view in FIG. 2 shows a modified example of the column base structure of the present invention, and the basic configuration is the same as the embodiment shown in FIG. (In the figure, only one is shown due to the vertical arrangement.) is screwed into the anchor bar 6, and then the column base 2 is attached to the anchor bar 6,
A nut 6a is screwed onto the bottom 2a of the column base from the outside. As shown in the figure, the column base 2 and the beam member 3 are connected by providing an end plate 4 at the joint with the beam member 3 at the upper part of the column base 2, and connecting them with a tensile joint bolt 10. The structure is as follows.

According to the above structure, the tension joint bolt 10 applied to join the beam member 3 and the column base 2 is not only not exposed as a protrusion on the upper surface of the beam member 3, but also extends from the left and right (horizontal direction). ) is effective in absorbing construction errors.

In addition to the above-mentioned embodiments, this embodiment also has a column base structure in which an anchor plate 5 is disposed between the column base 2 and the foundation 1, and the bottom end of the column base 2 has an angled configuration. include.

[0029]

As described above, according to the column pedestal structure according to the present invention, it is possible to adjust the level between each column pedestal fixed to the foundation, and it is possible to absorb construction errors in the vertical direction. In addition, the anchor reinforcement inserted into the foundation can be embedded in a large area, and as a result, errors in left and right construction and errors in the length of the beams to be joined can be absorbed.

On the other hand, the column base compensates for the drawbacks of tension bolt connection, such as the inability to absorb the accuracy of component dimensions and construction precision, thereby making tension bolt connection possible. Furthermore, since the present invention has a pin pedestal structure, it is possible to reliably transmit stresses such as axial force and shearing force, and although this pin pedestal requires rotational force, it is possible to form an unbonded part. This has made it possible to improve the deformability of anchor bars and prevent concrete from peeling off.

In addition, since concrete is poured at the bottom of the column base, safety against collisions with objects can be increased, and the construction is simple and reliable, making it suitable for this type of industry. This is a very useful invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the construction process for constructing a column base according to an embodiment of the present invention, in which A is a state in which anchor bars are inserted into the foundation and fixed, and B is a state in which the column base is inserted into the anchor bars. State and C respectively indicate a state in which the column base is fixed.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the column base of the present invention.

FIG. 3 is a schematic cross-sectional view showing a conventional column base structure;
b and c are general exposed type column bases, and d and e are pin column bases, respectively.

FIG. 4 is a schematic cross-sectional view for explaining a conventional column pedestal structure, in which A shows an example of a neck wrap type column pedestal structure, and B shows an example of an embedded type column pedestal structure.

FIG. 5 is a graph showing the relationship between the rotation angle of the anchor plate at the column base and the column base moment.

FIG. 6 is a schematic cross-sectional view showing a conventional column base structure.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: In an exposed column pedestal for civil engineering and architectural structures, the column pedestal whose bottom part is a bag part faces the foundation part, and an anchor reinforcement is provided between the bottom part of the column pedestal and the foundation part. The anchor rod is penetrated so that the relative position can be adjusted, and a filler material such as concrete is filled between the bag part of the bottom of the column pedestal and/or between the bottom of the column pedestal and the foundation. An exposed type column pedestal for civil engineering and architectural structures, characterized in that the mutual distance between the bottom part of the column pedestal and the foundation part can be adjusted and fixed by applying the function.