JP2002371798A - Steel timbering and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide steel timbering and its method of manufacture, reducing manufacturing costs while enabling roll bending work (cold working) to be achieved with a smaller radius of curvature. SOLUTION: A first steel member 2 having a T-shaped cross-sectional configuration is bent into a predetermined radius of curvature R1 by a flange 3 and a web 4. A second steel member 4 having an inverted-T-shaped cross-sectional configuration is bent into a predetermined radius of curvature R2 by a flange 5 and a web 6. The web 4 of the first steel member 2 is joined by welding w or bolted to the web 6 of the second steel member 4 so that the members are integrated into an H-shaped cross-sectional configuration having a predetermined radius of curvature R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a steel support used in the construction process of a steel sheet pile type foundation or a tunnel and a method of manufacturing the same, and more particularly, to an H-shaped cross section having a predetermined radius of curvature. The present invention relates to a steel support and a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, as a method of constructing a temporary cutoff wall in a temporary closed-type steel pipe sheet pile type foundation, which is one of the bridge foundations, as shown in FIG. A circular, oval, rectangular, or the like is combined and driven into a well-shaped closed shape, and a support (bending) 1 and a cutting beam 22 are installed inside and outside the head of each steel pipe sheet pile 21 to form a temporary cutoff wall. Form. Next, underwater excavation is performed in the temporary cutoff wall, and a steel pipe sheet pile 23 and a mid-sole single pile 24 that form a partition wall are driven into the ground support layer 20, a bottom concrete 25 is driven, a support is installed, and water is changed. Thereafter, the top slab concrete 26 and the skeleton concrete 27 are cast.

[0003] When such a shoring is installed, as shown in FIGS. 6A and 6B, if the shoring is circular and the diameter of the well is not so large, a beam is not used.
Since only the ring-shaped steel support 1 made of H-section steel is required, a large work space can be obtained, construction is easy, and the construction period can be shortened. In this case, although the support 1 depends on the size of the H-section steel, the minimum bending radius R of the bending of the H-section steel (H-300) is about 9 m.

[0004] On the other hand, the steel support used in the construction process of the tunnel has a shape similar to the excavated cross section of the tunnel.
The design must be made so that the applied load is transmitted well through shotcrete or the like, and the generated bending moment is minimized. FIG. 7 shows a form of the steel support 1 installed on the tunnel excavation section. As shown in FIG. 7A, a semicircle is provided only in the upper half, a horseshoe is provided in both the upper and lower halves as shown in FIG. As shown in FIG. 7 (C), there are various shapes such as a horseshoe with an invert installed all around, and as shown in FIG.
It is determined in consideration of the magnitude and direction of the applied load, the construction method, and the like. In this case, the steel shoring installed in the upper half part of the tunnel excavation section forms an arch shell structure continuous with the shotcrete in the axial direction of the tunnel and closely adheres to the ground. As shown in (A), the lower half is
In some cases, steel supports may be omitted.

[0005] Such a steel shoring may be divided into a plurality of pieces depending on the shape and size and the construction method. In this case, the position and structure of the joint of each steel material forming the steel support structure must be determined in consideration of the tunnel excavation cross-sectional shape, the construction method, the magnitude and distribution of the section force, and the like. As shown in FIGS. 8A, 8B, and 8C, the joint portion of the steel support 1 tends to be a structural weak point.
When a large earth pressure is applied, buckling or bending failure is likely to occur at the joint portion. Therefore, it is desirable to use the joint plate 31 to enable a strong connection by the bolt 32. If it is necessary to minimize the settlement, the joint plate 31
It is necessary to increase the size of the bottom plate 33 and the like, and to integrate with the shotcrete so as to obtain a sufficient supporting force.

Conventionally, when manufacturing the above-mentioned steel support, plastic working (cold working) by roll bending is performed on a steel material made of H-section steel formed by hot rolling.
It is bent to a predetermined radius of curvature.

[0007]

However, in the above-mentioned conventional means for manufacturing a steel support, in order to prevent a decrease in quality in terms of material such as toughness and aging effect due to plastic working, H steel is used.
It is necessary to limit the minimum radius of curvature according to the cross-sectional rigidity of a steel member made of a shaped steel.

For this reason, in order to manufacture a steel support, H
It is a process in which separate steel plates are used for the flange material and the web material forming the cross-sectional shape, and these steel plates are assembled into an H-shaped cross-sectional shape and welded by an all-build-up method. There has been a problem that the manufacturing cost increases, such as a large number of man-hours and material loss of the steel plate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and aims to reduce the manufacturing cost and to perform a steel bending work (cold working) with a smaller radius of curvature. It is intended to provide a method of manufacturing the same.

[0010]

In order to solve the above-mentioned problems, the present invention is configured as follows.

A first aspect of the present invention is a steel shoring, in which one end of a web is integrated at a middle portion in a width direction of a flange and has a T-shaped cross section which is bent to a predetermined radius of curvature. A first steel material, a second steel material having an inverted T-shaped cross-section in which one end of the web is integrated at a middle portion in the width direction of the flange and bent to a predetermined radius of curvature; The other end portions of the webs of the first and second steel materials are welded or bolted to each other to form an H-shaped cross section having a predetermined radius of curvature.

According to a second aspect of the present invention, in the first aspect, the web and the flange of the first and second steel materials are integrally formed by hot rolling.

[0013] In a third aspect based on the first aspect, the first steel material and the second steel material are obtained by cutting an intermediate portion of a web of an H-section steel formed by hot rolling. It is characterized by being formed.

A fourth invention is characterized in that, in the first invention, one end of the web of the first steel material is separately welded to an intermediate portion in the width direction of the flange.

A fifth invention is characterized in that, in the first invention, one end of the second steel material web is separately welded and joined to a widthwise intermediate portion of the flange.

The sixth invention is directed to the first, second, third, fourth or fifth aspect
The present invention is characterized in that an intermediate web member having a predetermined radius of curvature is arranged and joined between the other end portions of the first and second steel webs.

A seventh invention is a method of manufacturing a steel support, wherein a first steel material having a T-shaped cross section in which one end of a web is integrated at a middle portion in a width direction of a flange is provided. A step of bending to a radius of curvature, and an inverted T in which one end of the web is integrated at a middle portion in the width direction of the flange.
Bending a second steel material having a shaped cross section to a predetermined radius of curvature, and welding or bolting the other ends of the webs of the first and second steel materials to each other to form a predetermined radius of curvature. Forming an H-shaped cross section having the following characteristics.

An eighth invention is a method of manufacturing a steel support, wherein a first steel material having a T-shaped cross section in which one end of a web is integrated at a widthwise intermediate portion of a flange is provided. A step of bending to a radius of curvature, and an inverted T in which one end of the web is integrated at a middle portion in the width direction of the flange.
A step of bending a second steel material having a shaped cross section to a predetermined radius of curvature, a step of forming an intermediate web member having a predetermined radius of curvature made of a steel plate, and a step of forming each of the first and second steel materials. Welding or bolting the other end portions of the webs to each other into an H-shaped cross section having a predetermined radius of curvature with the intermediate web member interposed therebetween.

[0019]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described in detail with reference to the drawings shown in FIGS. FIG.
1 shows a first embodiment of a steel shoring according to the present invention.

As shown in FIGS. 1 (A) and 1 (B), the steel support 1 has an H-shaped cross section having a predetermined radius of curvature R used in, for example, a tunnel construction process.
The first steel material 2 having a predetermined radius of curvature R1 and the second steel material 5 having a predetermined radius of curvature R2 are joined and integrated by welding w.

That is, the first steel material 2 constituting the steel support 1 is formed such that one end 4a of the web 4 is integrated into a T-shaped section by hot rolling at the intermediate portion in the width direction of the flange 3. At the same time, a predetermined radius of curvature R1 is subjected to roll bending (cold working). On the other hand, the second steel 5
Also, as in the case of the first steel material 2 described above, one end 7a of the web 7 is integrated into an inverted T-shaped cross section by hot rolling at an intermediate portion in the width direction of the flange 6,
Roll bending (cold working) is performed on a predetermined radius of curvature R2.

The first and second steel materials 2, 5
The other end portions 4b and 7b of the webs 4 and 7 are butted against each other and welded to form a steel support 1 having an H-shaped cross section having a predetermined radius of curvature R as shown in FIG. It is.

FIG. 2 shows an example of a manufacturing process of the steel support 1 described above. As shown in FIG. 2A, an H-section steel 10 is formed by hot rolling. Next, this H-section steel 1
By dividing the neutral axis OO of the web 13 connecting the two flanges 11 and 12 of FIG.
As shown in (B), a first steel material 14 having a T-shaped cross section and a second steel material 15 having an inverted T-shaped cross section are formed. And the first
Steel material 14 by roll bending (cold working)
Bending is performed at a predetermined radius of curvature R1. On the other hand, the second steel material 15 is also bent at a predetermined radius of curvature R2 by roll bending (cold working), and the web ends 14a of the first and second steel materials 14 and 15 are formed. ,
15a is joined and integrated.

Incidentally, the Japan Society of Civil Engineers
Width of upper and lower flanges 11 and 12 in H-section steel 10 published in “Tunnel Standard Specification Book (Mountain Construction Method) and Commentary” issued on January 29, 2010 (Table 3.12 on page 88) a, a height dimension b, a thickness dimension c of the web 13 and a thickness moment d of the flanges 11 and 12, and a relation between the secondary moment of area I and the minimum radius of curvature R with respect to the neutral axis OO. According to this, when cold bending is performed on the H-section steel 10, its minimum radius of curvature R is determined by the Young's modulus E of the steel material.
Stiffness (EI), which is the product of the area moment of inertia I
Heavily dependent on Thereby, the bending rigidity (E
The larger the value of I), the more difficult it is to bend, so the minimum radius of curvature R is increased and limited. Conversely, the smaller the bending rigidity (EI) of the steel material, the easier it is to bend, so that the minimum radius of curvature R can be reduced.

Therefore, as in the present invention, the H-section steel 10
Is cut by a web neutral axis OO and is divided into a first steel material 14 having a T-shaped cross section and a second steel material 15 having an inverted T-shaped cross section. ) Can be reduced so that it is easy to bend, and the minimum radius of curvature R
1, R2 can be made smaller. For example, as the H-section steel 10, the material is SS400, and each flange 1
The width dimension a of 1, 12 is 100 mm, and the height dimension b is 100
mm, the thickness c of the web 13 is 6 mm, and the flange 1
When an H-section steel having a thickness d of 8 mm and a thickness dimension of 1, 12 is used,
The second moment of area I is 378 cm4, and the neutral axis O
The minimum radius of curvature R for -O is as large as 120 cm. On the other hand, the H-section steel 10 is
Steel material 1 when divided in half (b / 2) in its height direction
The second moment of area I of the samples 4 and 15 is 16.1 cm @ 4, which is extremely small at about 4%. Thereby, when performing cold bending, the neutral axis O1-
The minimum curvature radii R1, R2 for O1, O2-O2 can be made extremely small.

FIG. 3 shows a second embodiment of the present invention.
The first steel material 2 constituting the steel support 1 has a flange 3 and a web 4 formed separately from each other, and performs roll bending on the flange 3 made of a steel plate with a predetermined radius of curvature R1. The web 4 is cut out at a predetermined radius of curvature R1, and one end 4a of the web 4 is joined to a middle portion of the flange 3 in the width direction by welding w into a T-shaped cross section.
Similarly, the second steel member 5 also has a flange 6 and a web 7 formed separately from each other. The flange 6 made of a steel plate is subjected to roll bending at a predetermined radius of curvature R2, and the web 7 is formed from the steel plate at a predetermined curvature. The web 7 is cut out at a radius R2, and one end 7a of the web 7 is joined to an intermediate portion of the flange 6 in the width direction by welding w into an inverted T-shaped cross section. The other ends 4 of the webs 4 and 7 of the first and second steel materials 2 and 5 are formed.
b and 7b are joined by welding w to form an H-shaped cross-section having a predetermined radius of curvature R.

FIG. 4 shows a third embodiment of the present invention.
As in the first embodiment described above, the first steel material 2 constituting the steel support 1 has a T-shaped one end 4a of the web 4 formed by hot rolling at the intermediate portion of the flange 3 in the width direction. Roll bending (cold working) with a predetermined radius of curvature R1 is performed. On the other hand, also in the second steel material 5, similarly to the first steel material 2, one end 7 a of the web 7 is integrated with the inverted T-shaped cross section by hot rolling at the intermediate portion in the width direction of the flange 6. Then, roll bending (cold working) is performed at a predetermined radius of curvature R2. Then, the other end portions 4b, 7b of the webs 4, 7 of the first and second steel materials 2, 5 are formed.
In the meantime, the web 7 is formed from a steel plate by a predetermined radius of curvature R3 (R3
= R), and are joined to each other by welding w to form an H-shaped cross-section having a predetermined radius of curvature R, with the intermediate web members 8 cut out at (R) being interposed. In this case, by selectively using the intermediate web member 8 having a different width dimension in the height direction, the height dimension of the steel support 1 can be easily adjusted.

In each of the above embodiments, the other ends 4b, 7b of the webs 4, 7 of the first and second steel materials 2, 5 are used.
Are joined by welding w, but bolt joining with a joint plate or the like is also possible.

[0029]

As described above, according to the steel support of the present invention, the T-shaped section member is formed by bending the flange and the web to have a predetermined radius of curvature, while the inverted T-shaped section member is bent. And the web are bent to a predetermined radius of curvature, and the webs of the two T-shaped cross-section members are welded or bolted to form a H having a predetermined radius of curvature.
Since it is integrated into the shape of a cross section, the number of processing steps is smaller than before, and the material loss of the steel plate is small, so that the manufacturing cost can be reduced.

Moreover, since the rigidity of both T-shaped cross-section members is smaller than the rigidity of the conventional H-shaped cross-section member, the minimum radius of curvature by roll bending (cold working) can be further reduced.

[Brief description of the drawings]

1A and 1B show a steel support according to a first embodiment of the present invention, in which FIG. 1A is a front view, and FIG.
It is an expanded sectional view in the A line.

FIG. 2 shows a manufacturing process of a steel shoring, and FIG.
Is a cross-sectional view of the H-beam before cutting, and FIG. (B) is a cross-sectional view of the H-beam after cutting.

FIG. 3 is an enlarged sectional view showing a steel shoring according to a second embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view showing a third embodiment of a steel shoring according to the present invention.

FIG. 5 is an explanatory view showing a construction state of a temporary cutoff wall in a conventional steel pipe sheet pile type foundation that also serves as a temporary cutoff.

FIG. 6 (A) is a longitudinal sectional view showing an installed state of a shoring on a steel pipe sheet pile type foundation, and FIG. 6 (B) is a transverse sectional view.

7 (A), 7 (B), 7 (C), and 7 (D) are explanatory views showing a form of a steel shoring installed on an excavated cross section of a tunnel.

FIG. 8 shows an example of a joint and a bottom plate of a steel shoring. FIG. 8 (A) is an explanatory view of a joint portion in an upper half portion of a tunnel excavation cross section, and FIG. 8 (B) is an upper and lower half of a tunnel excavation cross section. And FIG. (C) is an explanatory view of a contact portion at the bottom of the tunnel excavation cross section.

[Explanation of symbols]

 Reference Signs List 1 steel support 2 first steel material 3 flange 4 web 4a one end 4b other end 5 second steel material 6 flange 7 web 7a one end 7b other end 8 intermediate web member 10 H-section steel 11 flange 12 flange DESCRIPTION OF SYMBOLS 13 Web 14 T-section steel 14a Web end 15 Reverse T-section steel 15a Web end O-OH H-section neutral axis O1-O1 T-section steel neutral O2-O2 Reverse T-section steel Neutral axis R Radius of curvature of steel support R1 Radius of curvature of first steel R2 Radius of curvature of second steel R3 Radius of curvature of intermediate web member w Welding

Claims (8)

[Claims] 1. A first steel material having a T-shaped cross-section formed by bending one end of a web at a middle portion in a width direction of a flange and being bent to a predetermined radius of curvature, and one end of the web being a flange. A second steel material having an inverted T-shaped cross-section integrated at a middle portion in the width direction and bent to a predetermined radius of curvature, and the other end of each of the webs of the first and second steel materials A steel support, characterized in that the portions are welded or bolted together to form an H-shaped cross section having a predetermined radius of curvature. 2. The steel support according to claim 1, wherein the web and the flange of the first and second steel materials are integrally formed by hot rolling. 3. The steel material according to claim 1, wherein the first steel material and the second steel material are formed by cutting an intermediate portion of a web of an H-section steel formed by hot rolling. 3. The steel support described in 3. 4. An end of a web of the first steel material,
The steel support according to claim 1, wherein the steel support is separately welded and joined to an intermediate portion in a width direction of the flange. 5. An end of the second steel web,
The steel support according to claim 1, wherein the steel support is separately welded and joined to an intermediate portion in a width direction of the flange. 6. An intermediate web member having a predetermined radius of curvature is arranged and joined between the other end portions of the first and second steel webs.
The steel support described in 3, 4 or 5. 7. A step of bending a first steel material having a T-shaped cross-section in which one end of the web is integrated at a middle portion in the width direction of the flange to a predetermined radius of curvature, and forming one end of the web into a flange. Bending a second steel material having an inverted T-shaped cross-section integrated at an intermediate portion in the width direction to a predetermined radius of curvature, and the other end of each of the webs of the first and second steel materials Welding or bolting to each other to form an H-shaped cross-section having a predetermined radius of curvature. 8. A step of bending a first steel material having a T-shaped cross-section in which one end of the web is integrated at a middle portion in the width direction of the flange to a predetermined radius of curvature; Bending a second steel material having an inverted T-shaped cross-section integrated at a middle portion in the width direction into a predetermined radius of curvature, and forming an intermediate web member made of a steel plate and having a predetermined radius of curvature. And welding or bolting the other end of each of the first and second steel materials to each other in the form of an H-shaped cross section having a predetermined radius of curvature through the intermediate web member. A method of manufacturing a steel shoring, comprising: