JPH041348A - Centrifugal cast-steel pipe - Google Patents

Abstract

PURPOSE:To impart strong proof strength to a steel pipe by forming the internal sectional shape of the steel pipe casted and molded while working centrifugal force in a shape corresponding to stress distribution in the axial direction and forming ribs inside the mounting sections of other members. CONSTITUTION:The internal cross section of a centrifugal casted steel pipe 1 casted while working centrifugal force is formed in a shape corresponding to stress distribution in the axial direction, ribs 10 are fitted on the insides, etc. of sections, to which girder members 2 are mounted, and the cross section of the steel pipe 1 is formed in a square shape and joining flanges 11 are formed on an outer circumference near one end section. The flanges 11 are abutted and fixed to the edge sections of the girder members 2, the steel pipe 1 and the girder members 2 are joined, and the flange 11 sections are used as mounting sections with the girder members 2. The horizontal ribs 10 are formed inside the flanges 11, and an internal sectional shape is formed in the square shape extending over adjacent opening ends from the ribs 10. Accordingly, proper sectional performance can be acquired extending over the whole regions in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a centrifugally cast steel pipe that is cast under the action of centrifugal force and is applied to pillars of buildings to form structural bodies.

(Prior Art) Steel pipes formed by so-called centrifugal force casting, in which casting is performed while applying centrifugal force, have already been applied to column members and the like, and are well known. By the way, in centrifugally cast steel pipes,
Normally, the outer shape is shaped into a tapered shape toward high stress areas, and reinforcement is gradually applied to improve the cross-sectional performance.

(Problems to be Solved by the Invention) However, conventional centrifugally cast steel pipes have an inner diameter that remains the same but an outer diameter that is expanded to increase the wall thickness. There was a problem in that it became difficult to arrange reinforcing bars. In addition, when this steel pipe is connected to other members, especially when the steel pipe is used as a column member and is connected to a beam member, large stress is transmitted from the beam member to the column member through the attachment site of these members. However, as in the past, simply reinforcing by changing the wall thickness tended to result in insufficient yield strength.

The present invention was devised in view of the above background, and has excellent cross-sectional performance that can cope with stress transmission at the attachment site with base members such as beam members, and ensures strength in the axial direction of the steel pipe. The object of the present invention is to provide a centrifugally cast steel pipe that can prevent local deformation in the axial direction and also allow easy reinforcement.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a steel pipe that is cast and formed while applying centrifugal force, the inner cross-sectional shape of which is shaped according to the stress distribution in the axial direction. In addition, a rib is formed inside the attachment portion to which other members are attached.

(Function) With the above structure, the inner cross-sectional shape corresponds to the stress distribution in the axial direction, so that appropriate cross-sectional performance can be obtained over the entire axial direction of the steel pipe. The ribs serve as reinforcement against stress transmission inside the attachment area.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partially cutaway side view showing a preferred embodiment of a centrifugally cast steel pipe according to the present invention. Figures 2 to 4 show the surfaces of each part of the centrifugally cast steel pipe.
They are sectional views taken along arrows nn, m-m, and ■-■, respectively.

The centrifugally cast steel pipe 1 according to the present invention is basically a steel pipe that is cast while applying centrifugal force, and has an inner cross-sectional shape that corresponds to the stress distribution in the axial direction.
A rib 10 is provided inside the attachment site where another member, for example the beam member 2, is attached.

What is shown in the same figure is an example in which a centrifugally cast steel pipe 1 is used as a column member. A joining flange 11 is thus formed.

By abutting and fixing this joining flange 11 to the edge of the beam member 2, the centrifugally cast steel pipe 1 and the beam member 2 are joined, that is, the joining flange 11 is the attachment part to the beam member 2. to do. A horizontal rib [0] is formed around the inner periphery of the joining flange 11, and from this horizontal rib 10 to the adjacent open end, the inner cross-sectional shape is as shown in FIG. It has a rectangular shape.

When the steel pipe 1 is applied to a column member in this way, the stress distribution in the axial direction is higher at the end where the joint flange 11 is formed at the attachment site with the beam member 2 than at the other end. In this embodiment, the centrifugally cast steel pipe 1 has an inner cross-sectional shape on the side where it is attached to the beam member 2, which is the high stress side, from the horizontal rib 10 site to the low stress side, as shown in FIGS. 2 and 3. The other end on the low stress side is set in a circular shape as shown in Fig. 4, and the other end on the low stress side is set in a square shape as shown in Fig. 4.
In other words, on the high stress side, the inner cross-sectional shape is set to a circular shape that allows thicker corners to increase the cross-sectional area to increase strength, and conversely, on the low stress side, the thickness of the corner portion is reduced to reduce weight. The shape is set to be a rectangular shape that can achieve this, and the shape is gradually changed from a circular shape to a rectangular shape from the high stress side to the low stress side.

Therefore, according to such a configuration, since the inner cross-sectional shape corresponds to the stress distribution in the axial direction, appropriate cross-sectional performance can be obtained over the entire axial direction of the centrifugally cast steel pipe 1. It is possible to effectively prevent local deformation of.

The horizontal ribs 10 serve as reinforcement against stress transmission inside the attachment area where high stress occurs. Therefore, it is possible to exhibit strong yield strength and to reliably support other members to be joined.

In addition, since the inner shape of the openings at both ends is a rectangular shape that follows the outer shape, there are fewer joining surfaces during butt joining, and joining work such as welding can be facilitated. Thereby, poor adhesion can be prevented and a strong joint can be achieved.

Furthermore, since the outer cross-sectional shape is simply a rectangular shape and there is no tapered portion for reinforcement as in the conventional case, reinforcing bars and the like can be easily accommodated.

In this centrifugally cast steel pipe 1, it goes without saying that the outer and inner shapes of the cross section are not limited to the shapes disclosed in this embodiment, and can be changed as appropriate.

(Effects of the Invention) As described above in detail in the Examples, according to the centrifugally cast steel pipe according to the present invention, the inner cross-sectional shape corresponds to the stress distribution in the axial direction, so the axial direction of the steel pipe Appropriate cross-sectional performance can be obtained over the entire area. Further, since the ribs serve as reinforcement against stress transmission inside the attachment area, strong yield strength can be exhibited.

[Brief explanation of drawings]

Figure 1 is a side view showing one embodiment of the present invention, Figures 2 to 4
The figure is a cross-sectional view taken along arrows nn, mm, and IV-TV in FIG. 1, respectively. 1... Centrifugal force cast steel pipe 2... Beam members (other members) 10...
・Horizontal rib (rib)

Claims (1)

[Claims] A steel pipe that is cast and formed while applying centrifugal force, and is characterized by having an inner cross-sectional shape that corresponds to the stress distribution in the axial direction, and ribs being formed inside the attachment area where other members are attached. Centrifugally cast steel pipe.