JP2601561B2 - Joining method of cylindrical column and beam - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for joining a column and a beam constituting a building structure, and particularly has a pair of stiffener rings, and a pipe thickness between the stiffener rings. The present invention relates to a method for joining a cylindrical column and a beam having a joint portion having a larger thickness than other portions.

[Conventional technology]

Since a steel pipe for construction used as a pillar of a building must be resistant to compression in the pipe axis direction and have high torsional rigidity, an extremely thick steel pipe is required. Conventionally, centrifugal steel pipe columns made by centrifugal casting have been widely used to satisfy this specification.

In such a centrifugal steel pipe column 1, as shown in FIG. 5, a stiffener ring 3, which is a kind of a joint reinforcement part having a large thickness, is formed integrally with the steel pipe itself in a joint area with the beam 2. ing. Further, when a beam 20 having a smaller height is joined in the joint area with the beam 2, the smaller beam 20 is positioned between the pair of stiffener rings 3 and 3 'for the larger beam 2 so as to fit to the spine. An extra ring 4 which is a kind of joining reinforcement method for joining the lower side of the beam is formed integrally with the steel pipe itself, or as shown in FIG. 6, the extra ring 4 and the stiffener ring 3 are joined together. To form a special stiffener ring 4 'having a width sufficient to allow the joining of two beams in the axial direction. The latter conventional method is disclosed in, for example, Japanese Utility Model Publication No. 55-20881.

In this way, when beams of different sizes are added to the joint area between the cylindrical column and the beam, that is, beams with different beam backs are joined,
Since an extra ring or a special wide stiffener ring is required for the back, the manufacturing cost is increased.

[Problems to be solved by the invention]

An object of the present invention is to provide a wide ring that is an extra ring or a special wide stiffener ring added to supplement the rigidity of a joint when there are a plurality of beams having different heights in the same joint area in joining a cylindrical column and a beam. Is to provide a column-to-beam joint method for minimizing the reliability while maintaining safety reliability.

[Means for Solving the Problems] In order to solve the above problems, in the method for joining a cylindrical column and a beam according to the present invention, direct joining for evaluating joining a beam directly to a pipe wall between the pair of stiffener rings is evaluated. The location is determined, and the amount of deformation of the direct joint between the cylindrical column and the beam in the vicinity of the stiffener ring generated when an axial load is applied to the cylindrical column forming the direct joint is the cylindrical shape. It is calculated from the outer diameter of the column and the diameter-thickness ratio, and as the calculated deformation amount is equal to or less than a predetermined value, the direct bonding portion is created by the pair of stiffener rings assuming that the bonding specification in design is satisfied. If it is evaluated that the beam is within the rigid restraint area, the beam is directly joined to the cylindrical outer wall of the cylindrical column that has actually come off at least one of the stiffener rings at the direct joint. Is done.

[Action]

Since the joints forming the stiffener ring have an increased wall thickness, the vicinity of the stiffener ring should also be able to benefit from the stiffener ring to a certain degree of rigid restraining effect. Noting this,
Perform elasto-plastic analysis on the load in the axial direction of the cylindrical column at the direct joint to be evaluated, and if the calculated amount of deformation of the direct joint is within the specified range, meet the design joint specifications, Based on the outer diameter and wall thickness of the cylindrical column, it is evaluated that the stiffener ring at the joint has entered a rigid reinforcement area (hereinafter referred to as a constrained area). Without additional formation, the cylindrical column and the beam are joined directly, that is, to the cylindrical outer wall of the cylindrical column separated from at least one stiffener ring. In other words, the restricted region on the rigidity of the pair of stiffener rings is a region in which the tube thickness between the pair of stiffener rings is thicker than the other portions, even when used for beam joining, the increased tube thickness and This area does not lose its design function as a joint because it is not easily deformed by the stiffener ring.

〔The invention's effect〕

Elasto-plasticity using computer simulations, even if multiple beams joined to a cylindrical column cannot be made equal in beam level or cross section for design or economic reasons and a common stiffener ring cannot be used In the constrained region by the stiffener ring determined by the analysis, the joint between the cylindrical column and the beam is not prepared and performed through a pair of stiffener rings, but the joint is performed in a state where it is disengaged from at least one stiffener ring Reliability, and as a result, additional stiffener rings and wide rings can be omitted while ensuring safety, reducing the manufacturing cost of cylindrical columns and simplifying the connection between cylindrical columns and beams Becomes

[Other features]

In the present invention, when judging whether or not the joint of the beams having different backs is in the restraining region of the nearby stiffener ring, the present invention provides an axial load on the cylindrical column with the beam directly connected to the cylindrical column as a fulcrum. Calculate the radial displacement or axial displacement of the direct joint caused by applying a load, and the displacement is the radial displacement or axial displacement of the joint when the beam is joined via an extra ring. It is proposed to determine that the direct joint is within the constrained region as long as it is within 115% of the volume. Thereby, it was experimentally and empirically confirmed that the beam was directly joined to the cylindrical column with sufficient strength and deformation performance without forming an additional stiffener ring. In the case of a beam that is joined to a cylindrical column with an upper side and a lower side, if it is determined that the direct joining point between the upper side and the lower side is within the rigidity constraint area of the nearby stiffener ring, both sides, that is, the joint cross section of the beam The whole can be directly joined to the cylindrical column. This is expected to have a great economic effect.

〔Example〕

In this embodiment, a centrifugal steel pipe column is used as a cylindrical column as a support of the building structure. The steel pipe column 1 is joined to the beam 2 as shown in FIG. Stiffener rings 3, 3 'are provided as reinforcing portions. Usually, since an I-shaped or H-shaped beam is joined to this stiffener ring, an upper stiffener ring 3 and a lower stiffener ring 3 'are provided at intervals so as to correspond to the back of the beam. The beams are joined with sufficient rigidity. In the case of joining beams having different backs in different horizontal directions in the vicinity of the joints joined by using the stiffener rings 3, 3 ', for example, as described in the description of the prior art, for example, When the beam 20 whose back is shorter than the distance between the upper stiffener ring 3 and the lower stiffener ring 3 'is joined, the lower side portion 20' of the beam is joined.
A joining reinforcement such as an extra ring will be added just above the lower stiffener ring 3 'for joining. However, if the connecting point between the lower side of the beam and the steel tube column is located near the lower stiffener ring 3 ', depending on the distance between them, the joint may be strengthened by the lower stiffener ring 3'. , There is a possibility that the joint has the allowable strength and stiffness that are allowed by the design without necessarily requiring the extra ring. The following procedure is proposed to determine this in a reliable and practical manner.

First, a model as shown in FIG. 2 is conceivable in order to examine the rigidity of a joint without such extra ring. In this model, when a vertical load P0 is applied to the steel pipe column supported on the column S at the lower side of the cross beam 20 on both sides, the horizontal direction of the junction point Z between the steel column 1 and the lower side 20 'of the horizontal beam 20 is measured. Find the displacement δ. In this case, the displacement also depends on the steel column and beam size.
Considering the horizontal tensile force P1 applied to the joint Z from P0 (a compressive force is generated at the upper side of the cross beam), the displacement δ is calculated from the horizontal force P1 by a numerical analysis by a finite element method using a computer. calculate.

From this, a graph showing the relationship between the displacement δ and the load P1 at a predetermined diameter-to-thickness ratio D / t (D: outer diameter of the steel pipe column, t: wall thickness of the steel pipe column) is shown in FIG. 3 'and cross beam 20
Can be obtained for each distance h from the junction.

The curve shown by the solid line is h = 0, that is, the case where the beam is joined to the stiffener ring. Since the inclination in the elastic region represented by the straight line portion of these curves, that is, the ratio of displacement to load, is the deformation rate of the joint, h =
When the slope obtained from the curve of 0, that is, a curve having a slope within 115% of the deformation rate, is calculated, the slope between the maximum lower stiffener ring and the beam joint where the deformation rate is within a predetermined range is determined. Is determined. In addition,
The determination criterion of 115% is determined experimentally and empirically for a standard frame, and can be appropriately changed depending on the structural form of the building to be applied, the building standard, and the like. From the hmax determined in this way and the diameter-to-thickness ratio corresponding thereto: D / t and the data obtained in the experiments actually performed, in the joint between the steel pipe column and the beam in the vicinity of the stiffener ring,
The displacement of the joint directly joined without the extra ring is the displacement of the joint when joined using the extra ring.
The maximum distance hmax from the nearby stiffener ring, which is guaranteed to be within 115%, to the joint of the cross beam can be related by the outer diameter D of the steel pipe column and the diameter / thickness ratio D / t of the steel pipe column. That is, a function G that satisfies hmax = G (D / t, D) is determined. With this function G, hmax is immediately calculated from the diameter / thickness ratio D / t.

Here, the reason why the diameter / thickness ratio D / t is used as a parameter is that the diameter / thickness ratio D / t is considered to have the most influence on the constraint area.

In order to further facilitate the user's convenience, if the maximum distance hmax from the nearby stiffener ring to the joint of the beam corresponding to various outer diameters and wall thicknesses using this function G is tabulated,
It is possible to reliably and easily determine whether to join without extra ring or to join with extra ring.

In this embodiment, a centrifugal steel pipe column is described as a cylindrical column. However, the present invention can be applied to a cylindrical column used as a column for other building structures.

[Brief description of the drawings]

FIG. 1 is a side view showing a connection between a steel pipe column and a beam, FIG. 2 is a view showing a model of a beam directly connected to the steel pipe column, and FIG. 3 is a beam connected to a steel pipe column via a stiffener ring. FIG. 4 is a graph showing displacement of a joint point between a steel pipe column and a beam with respect to a load, and FIGS. 5 and 6 are side views showing a conventional joint between a steel pipe column and a beam.

Claims (5)

(57) [Claims] 1. A method for joining a cylindrical column and a beam having a pair of stiffener rings for joining with a beam, and having a joining portion in which a pipe thickness between the pair of stiffener rings is thicker than other portions. A direct joining point for evaluating that the beam is directly joined to a pipe wall between the pair of stiffener rings is determined, and the stiffener generated when an axial load is applied to a cylindrical column forming the direct joining point. The deformation amount of the direct joint between the cylindrical column and the beam near the ring is calculated from the outer diameter and the diameter-thickness ratio of the cylindrical column, and the calculated deformation amount is equal to or less than a predetermined value. If it is evaluated that the direct joint part falls within a rigid restraint region created by the pair of stiffener rings as satisfying the above joint specification, the beam is actually formed at the direct joint part. Is a method of joining a cylindrical column and a beam directly joined to a cylindrical outer wall of the cylindrical column separated from at least one stiffener ring. 2. The method according to claim 1, wherein a radial displacement amount of the direct joint portion caused by applying an axial load to the cylindrical column with a beam directly joined to the cylindrical column as a fulcrum is calculated as a deformation amount of the direct joint portion. As long as the displacement amount is within 115% of the radial displacement amount when the beam is joined via the stiffener ring, the direct joining portion is in the constrained area and satisfies the design joining specification. The method for joining a cylindrical column and a beam according to claim 1 to be evaluated. 3. The amount of axial displacement of the directly joined portion caused by applying an axial load to the cylindrical column with the beam directly joined to the cylindrical column as a fulcrum is calculated as the amount of deformation of the directly joined portion. As long as the displacement amount is within 115% of the axial displacement amount when the beam is joined via a stiffener ring, the direct joining portion is in the constrained area and is evaluated as meeting the design joining specification. The method for joining a cylindrical column and a beam according to claim 1 to be performed. 4. An apparatus according to claim 1, wherein only an upper side or a lower side of said beam is directly joined to said cylindrical column near said stiffener ring.
4. The method for joining a cylindrical column and a beam according to any one of items 3 to 3. 5. The method according to claim 1, wherein an upper side and a lower side of the beam are directly joined to the cylindrical column in the vicinity of the stiffener ring.