WO2002060614A1

WO2002060614A1 - A method for manufacturing box girder, a box girder and a constructional part therefor

Info

Publication number: WO2002060614A1
Application number: PCT/FI2002/000068
Authority: WO
Inventors: Matti Koskinen
Original assignee: Innowork Oy
Priority date: 2001-01-31
Filing date: 2002-01-30
Publication date: 2002-08-08
Also published as: FI110238B; FI20010187A; FI20010187A0

Abstract

The invention relates to a method for manufacturing an elongated box girder assembled with a solid joint (100) from at least two separate prefabricated structural components. The method comprisestaking at least one structural component (3) having at least one border area (11) and taking at least one second structural component (4), the plate having a second or a third thickness. The border area is shaped by shifting the edge of the first plate laterally in a direction perpendicular to the plate surface (10) over a distance equalling the thickness of the second plate to form a support surface (30) parallel with the surface of the finished structural profile at the joint of the structural components. Said structural components are joined with said border area overlapping with the second structural component to be joined at the joint ofthe structural components, the overall outer surface of the structural profiles being substantially planar at the joint between the structural components.

Description

A Method for manufacturing a box girder, a box girder and a constructional part therefor

The invention relates to a method for manufacturing a box girder from a plurality of prefabricated structural components, more specifically to a method for manufacturing an elongated box girder assembled from at least two separate prefabricated structural components with a solid joint. The invention also relates to a box girder assembled with a solid joint from at least two separate prefabricated structural com- ponents. The invention further relates to a prefabricated structural component in a box girder.

The following description focuses on the domain of tubular structural profiles made of steel, i.e. tubular girders, which is a major field of application of the invention described below. To manufacture conventional tubular steel girders, efficient mass production methods have been developed, allowing efficient production of standard structural profiles having standard sizes and cross-sections. Tubular girders are manufactured i.a. with a large-scale production method for bending a steel tape by roll forming to the shape of a circular tube, for welding it with additive-free high- frequency welding to form a pipe, which is further moulded between rollers into an angular tubular girder. In use, these girders have the drawback of their cross- sectional shapes and dimensions and the adopted wall thickness being restricted to standard dimensions and standard materials. Cross-sections with special dimensions and shapes required in small production lots cannot be profitably manufactured with conventional mass production methods. Nor is it possible to manufacture tubular girders with varied cross-sections with prior art mass production methods. Especially regarding architectural objects, there is an increasing need for using freely selected profile cross-sections, which also vary in cross-section, and also curved structural profiles. Standard tubular girders are very ill suited for objects where optimis- ing the weight, durability and rigidity properties of box girders is necessary. To overcome these shortcomings, it is a widely known and common practice to manufacture special profiles by joining components by welding, providing thus the desired cross-section. Plates welded together at their corners or structural components welded at a butt joint are conventionally used, and in such cases, the components are subjected to very high precision and quality requirements regarding their manufacture and welding to ensure a joint seam of high quality and durability. JP patent specification 9239626 discloses a method and an installation for manufacturing a tubular structural profile from separate structural components with a mechanical jointing method. However, in order to be profitable, the use of the method described calls for extremely large production volumes, and the method described does not allow the production of varying cross-sections. In addition, the structural components of the described structural profile has a complex joint design, which prerequisites a high pref abdication degree of the structural components.

The invention described below eliminates the shortcomings mentioned above and also yields notable improvements both to the properties and the optimising potential of the box girders and to the rationalisation of the manufacture of box girders.

The invention described below is characterised by the features defined in the characterising part of claims 1, 6 and 12. The edge shape of the profile or plate-like structural component integrated in the box girder constitutes a support and guide element and an interface, and in the case of a welded joint, also a groove and a backing for the welded joint, as well as a guide element for a welding manipulator or robot. The invention is particularly suitable for the production of small-sized and medium-sized production series and demanding individual products. The method for jointing the structural components of the invention offers a plurality of produc- tional advantages, such as more efficient welding operations owing to the backing. The joint of the structural components forms an advantageous welding groove shape and the plate edge acts as an efficient guide for the welding manipulator, allowing the use of efficient welding methods, such as mechanised submerged arc welding. The shape of the joint of the structural components of the invention also allows the use of wider production tolerances regarding the straight plate edge connected to the shaped structural component, given the allowed variation of the position of the plate edge in the overlapping joint without detriment to the function or the appearance of the joint. At the assembly stage of the box girder, the components bear against each other, so that the need for guides and jigs is small compared to conventional jointing of straight plate edges.

The box girders of the invention can be used at several different objects, such as, for instance, to form elements of building and structural frames, as columns, beams, bridge constructions, boxes etc. A tubular girder is a typical example of a box girder. The material used in the structural components of the box girders of the invention may consist of various raw materials jointed by welding, such as steel and aluminium. In addition, various material combinations are usable, the structural components of the finished box girder being made of different materials. The different structural components of the box girder made also be made of steel qualities of varying strength.

In industrial applications of the invention, it is advantageous to manufacture a number of standard structural components or standard profiles provided with the edge shape of the invention, i.e. with an efficient roll-forming method, and to make the remaining structural components of the box girder i.e. from guillotine sheared, form-cut planar or bevelled plate parts, as illustrated in the drawings below. Mini- mum bending radius is used in the manufacture of the edge shape of the structural component, equalling the plate thickness in the optimal case.

The box girder of the invention is especially suitable for use also in connection with a steel/concrete joint structure, in which the box girder made of steel acts as a cast- ing mould remaining in the structure for the concrete and also forms part of the reinforcement. Additional structures are easy to fasten by welding to the steel surface of the joint beam or column, and the steel cover acts as a mechanical shield for concrete and as a fire prevention for concrete.

Details and embodiments of the invention are described below in the form of drawings.

Figures 1 and 2 show principal solutions of the cross-section of the structural component joint in the box girder of the invention, before and after the welding of the joint, at location I of figure 4, but on a larger scale.

Figure 3 shows a first embodiment of the profiles of the invention in rectangular profile, in a cross-section perpendicular to the length of the box girder.

Figure 4 shows another embodiment of the profiles of the invention, using two identical standard profiles of the invention and freely dimensionable planar structural components, in a cross-section perpendicular to the length of the box girder.

Figure 5 shows in a cross-section corresponding to figures 1-4 standard profile blanks made by roll forming, from which standard profiles of figures 6, 7 and 8 can be manufactured by bevelling. Figures 6-8 show various conceivable cross-sectional shapes of standard profiles of the invention, in cross-sections perpendicular to the length of the profiles.

Figure 9 shows a third embodiment of the profiles of the invention, where the web plates of the box girder have been shaped, in a cross-section perpendicular to the length of the box girder.

Figure 10 shows a fourth embodiment of the profiles of the invention, i.e. a box girder varying in cross-section, supported at the ends and viewed laterally.

Figure 11 shows a fifth embodiment of the profiles of the invention, i.e. a box girder in which standard profiles of the invention and bevelled plate parts have been used for manufacturing a conical column, in a cross-section perpendicular to the length of the box girder.

Figure 12 shows a sixth embodiment of the profiles of the invention, i.e. a box girder in which the box girder of the invention is used in the joint construction, in a cross-section perpendicular to the length of the box girder.

Figure 13 shows a seventh embodiment of the profiles of the invention, i.e. an oblong cross-surface, which has been made from a blank manufactured by roll- forming in accordance with the invention, with blanks joined facing each other, in a cross-section perpendicular to the length of the box girder.

Figure 1 shows a cross-section of the joint between structural components of a box girder of the invention before the welded joint between these has been made. The edge of the first structural component 1 is shaped so as to overlap the straight edge of the second structural component 2 in the joint over a distance L, with the outer surface 10, the upper surface in the figure, being planar. The design and shape of the joint allows the production tolerance of the second structural component 2 to vary within the limits of the dimensional variation ΔL without detriment to the operation or appearance of the joint. The structural components 1 and 2 may have the same or different material thickness SI and S2, the height H_s of the parallel displacement of the border area 11 of the first structural component 1 being determined by the material thickness S2 of the second structural component 2. In practical constructions, a typical material thickness SI, S2 at the objects of application of the invention is in the range 3 mm - 10 mm. Figure 2 shows a practical embodiment of the structural component joint of figure 1 in cross-section after the welded joint 12 has been made. The edge N of the second structural component 2 acts as a guiding element in welding for the welding manipulator or robot, allowing welding to be mechanised or automated in a practical manner.

Figure 3 shows an embodiment of the invention, in which a standard profile made e.g. by roll forming, i.e. the third structural component 3, is jointed to the bevelled U-profile, i.e. the fourth structural component 4. The lateral dimension HI of the fourth structural component 4 is determined under the requirements imposed by the overall height H2 of the box girder. The production inaccuracy of the dimension HI of the fourth structural component 4 can, to a given limit value, be compensated at the welding point 13a, 13b at the stage of jointing the structural components. The box girder 6.2 of the invention is characterised by the angular rounding with large radius R shown in the figure, the surface finishing of the box girder by painting, for instance, being more advantageous than with profiles having sharp angles. In addition, the profile has more efficient operation in terms of material strength than does an otherwise identical structural profile with sharp angles. The box girder 6.4 shown in figure 13 corresponds otherwise to that of figure 3 and the standard profile 25 corresponds otherwise to the one depicted above, except that two such standard profiles 25 can be joined directly, and for this purpose they comprise one single parallel-displaced border area 11 or 21.

The box girder 6.5 shown in figure 4 is formed of two identical standard profiles of the invention, such as a third structural component 3, which are joined with planar web plates 5 of desired dimensions. With the web plates 5 disposed in a longitudinal direction perpendicular to the figure plane, the wedge-shape achieves a box girder that is readily varied in cross-section.

Figure 5 shows a cross-sectional view of a standard profile blank 20 of the invention, made by roll forming, which can be reprocessed by bevelling to the shape of the standard profiles 3, 14 and 15 shown i.a. in figures 6 and 7 and 8. Of course, standard profiles can be roll-formed directly in the final shape, and then no separate reprocessing step will be necessary. The standard profiles shown in figures 5-8 may also be asymmetrical, with the different border areas 11 and 21 of the plate having different bends, i.e. parallel displacements H_s, or with the bends, i.e. parallel displacements H_s made only in one border area 11 or 21 of the plate. Figure 9 shows an embodiment of the box girder 6.6 of the invention in cross- section, using two identical standard profiles, i.e. the third structural component 3 described repeatedly above, and web plates 16 connecting these as desired. In beam constructions, the web plates 16 may have a material thickness S3 that is notably smaller than the plate thickness SI of the upper and lower flanges Py, Pa, i.e. of said standard profiles, allowing them to be more readily shaped by various methods and composite and conspicuous architectural constructions to be obtained.

Figure 10 shows a box girder 6.1 in lateral projection, in which the standard U- profile of the invention serving as upper flange Py, i.e. the third structural component 3, is bent to a curved shape. The lower flange Pa of the box girder is also a standard U-profile 3 of the invention, which is straight. Web plates 5 cut to shape are welded between the flanges, forming thus an architectural box girder construction that varies in cross-section. The cross-section of the box girder may have the structure of figure 4, for instance.

Figure 11 shows the structure of a conical column 6.3 in cross-section. The structure consists of two standard profiles 14 with standard cross-section of figure 7 and of two plate blanks 17 cut in trapezoidal shape and bevelled centrally with the same radius R as the angle of the standard profile.

Figure 12 shows a cross-section of a box girder of the invention 6.7, which is intended for use in steel-concrete joints. The structural components 8a and 8b are identical in shape and special embodiments of the standard profile provided with the edge profile of the invention, i.e. parallel-displaced border areas 11, 21, where the edge shape is additionally provided with one or more additional bends 18, forming a grip means directed inwardly into the structural profile, for joining concrete and steel. In the optimal embodiment, the inwardly directed grip means, i.e. the additional bends 18, have a roughened or profiled surface 19, or a perforated surface, providing efficient grip. The ledge-like levels formed by the grip means can be utilised also in the fastening of the supplementary reinforcements 23 within the tubular girder and in the support. The construction of the invention allows the box girder to be internally equipped, after which the box girder is assembled by means of welding. If a horizontal box girder is being concerned, the upper surface profile is equipped with concrete cast inlets 24.

In conclusion, we note that the method comprises the following steps. 1} Taking at least one structural component 1; 3; 8a, 8b; 14; 15, having at least one border area 11 and/or 12 formed of a first plate. II} Taking at least a second structural component 2; 4; 5; 16; 17 formed of a second plate, the plate having a second or third thickness S2, S3. Ill} Shaping said border area 11 and/or 21 by shifting the edge of the first plate in a direction perpendicular to the plate surface 10 and laterally over a distance equalling the thickness S2 and/or S3 of the second plate, forming a support surface 30 parallel to the finished structural profile surface 10 at the joint between the structural components. IV} Joining said structural components so that said border area 11 and/or 12 overlaps the second structural component 2; 4; 5; 16; 17 to be joined at the joint between the structural components, the overall outer surface 10 of the structural profiles being substantially planar at least at the joint between the structural components.

The drawings show but a few examples of practical applications of the invention. The optimal properties of the invention lie precisely in the manufacture of freely shaped and dimensioned and also variable structural profile cross-surfaces, the number of practically feasible optional cross-sections and structures being nearly unlimited.

The invention is more in detail characterised by the features defined in the claims.

Claims

1. A method for manufacturing an elongated box girder assembled with a solid joint (100) from at least two separate prefabricated structural components, characterised in comprising the steps of:

- taking at least one structural component (1; 3; 8a, 8b; 14; 15) having at least one border area (11 and/or 21) consisting of at least one first plate;

- taking at least one second structural component (2; 4; 5; 16; 17) consisting of a second plate having a second or a third thickness (S2, S3); - shaping said border area (11 and/or 21) by shifting the edge of the first plate laterally in a direction perpendicular to the plate surface (10) over a distance equalling the thickness (S2 and/or S3) of the second plate to form a support surface (30) parallel with the surface (10) of the finished structural profile at the joint of the structural components; - joining said structural components, said border area (11 and/or 12) overlapping with the second structural component (2; 4; 5; 16; 17) to be joined at the joint of the structural components, and the overall outer surface (10) of the structural profiles being substantially planar at least at the joint of the structural components.

2. A method as defined in claim 1, characterised in that the structural components are made of a weldable material and that the structural components are joined by welding at least from the outer surface of the finished structural profile.

3. A method as defined in claim 1 and 2, characterised in that the shaping of the edge profile of the structural components is performed by roll forming a plastically ductile material.

4. A method as defined in claim 1 and 2, characterised in that the shaping of the edge profile of the structural components is performed by means of a bevelling press from a plastically ductile material.

5. A method as defined in claim 1, characterised in that the shaped structural component edge forming a joint between the structural components continues tucked within the finished structural profile after the overlapping interface of the structural components.

6. An elongated box girder (6.1-6.7) assembled with a solid joint (110) from at least two separate prefabricated structural components, characterised in that the box girder comprises: at least one structural component (1; 3; 8a, 8b; 14; 15) having in a border area (11 and/or 21) formed of at least one first plate a design such that provides at the joint between said border area and at least another structural component (2; 4; 5; 16; 17) formed of a second plate an overlapping support surface parallel to the finished box girder surface for a second structural component to be joined, and that the outer surface of the box girder is planar at the joint between the structural components.

7. A box girder as defined in claim 6, characterised in that the structural compo- nents are made of a weldable material and that the structural components have been joined by welding at least from the outer surface of the finished structural profile.

8. A box girder as defined in claims 6 and 7, characterised in that at least one structural component consists of a structural component made by roll forming.

9. A box girder as defined in claims 6 and 7, characterised in that the edge profile of the structural components are shaped by means of a bevelling press.

10. A box girder as defined in claim 6, characterised in that the shaped structural component edge forming a joint between the structural components continues tucked within the structural profile after the overlapping intersurface between the structural components.

11. A box girder as defined in claim 6, characterised in at least one structural com- ponent in the box girder having varying cross-sectional surface, the box girder assembled from structural components varying in cross-section.

12. An elongated prefabricated structural component of a box girder, characterised in comprising a plate area (11 and/or 21), at least one longitudinal side of which is bent at a distance (L) from the structural component edge and shifted in parallel with the plate surface (10) over a distance (H_s), preferably equalling the thickness (S2 or S3) of the second plate to be joined, forming a staggered ledge (30) with a view to joint welding (12).

13. A structural component of a box girder as defined in claim 12, characterised in that one or more folds matching the shape of the cross-section or part of the cross- section of the box girder have been made in the plate area transversely to the longitudinal axis of the plate area.

14. A structural component of a box girder as defined in claim 12 or 13, characterised in that after bends made with a view to shape its cross-section, the structural component has been curved in the longitudinal direction or bent to the desired pro- file shape.

15. A structural component of a box girder as defined in claim 12, 13 or 14, characterised in that the plate thickness is 3-10 mm.