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Two-sided welding method for U-shaped ribbed slab unit welding seam

A rib and fillet weld technology is applied in the field of double-sided welding of U-rib unit welds, which can solve the problems of fatigue cracking of orthotropic steel bridge decks, unreasonable weld forms, and large bending stress. Extremely low risk of weld cracks, avoidance of arc breaks, reduced stress amplitude effects

Inactive Publication Date: 2017-04-19
WUCHUAN HEAVY ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Steel box girders are generally composed of panel unit elements and floor unit elements. Orthotropic deck decks have the advantages of light weight and rapid construction, and are widely used in long-span bridges. All kinds of fatigue cracking problems of heterogeneous steel bridge decks are prominent, which has always troubled bridge builders
In the past few decades, researchers have gained a lot of experience and lessons, and carried out a lot of research work, aiming at improving and optimizing the welding details of orthotropic steel bridge deck, improving durability; but limited to the existing technology, U rib It can only be welded to the bridge deck from the outside. This kind of fillet weld is eccentric to the web of the rib. The bending stress of the wheel load acting on the root of the U-rib fillet weld through the bridge deck is too large. The existence of tensile stress increases the maximum effective tensile stress value at the tip of the incomplete weld root, so it is easy to produce fatigue cracks initiated from the root of the weld
In addition, the connection weld between the U rib and the unit element of the steel box girder bottom plate can only be welded from the outside, and the form of the weld is not reasonable

Method used

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  • Two-sided welding method for U-shaped ribbed slab unit welding seam
  • Two-sided welding method for U-shaped ribbed slab unit welding seam
  • Two-sided welding method for U-shaped ribbed slab unit welding seam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Embodiment 1 of the present invention is used for the double-sided welding method of U-rib unit welds, including the following steps:

[0052] S101. Polish and clean the rust, oil stain, paint and oxide skin on the area to be welded on the upper end surface of the bridge deck and within the range of 20-30 mm on both sides, so as to expose the metallic luster;

[0053] S102. Put the U rib upside down on the bridge deck. At this time, an assembly groove is formed between the bottom end of the U rib and the upper surface of the bridge deck. The angle of the groove is 55°, and the blunt edge of the assembly groove is 1-2 mm. The assembly gap between the U-rib and the bridge deck is 0-0.75mm; figure 2 Shown is a schematic diagram of the assembly groove formed between the U-rib and the bridge deck in Embodiment 1 of the present invention.

[0054] S103, performing tack welding on the U-rib and the bridge deck in the horizontal position to obtain a U-rib unit, the tack weldi...

Embodiment 2

[0059] Embodiment 2 of the present invention is used for the double-side welding method of U-rib unit welds, including the following steps:

[0060] S201. Polishing and cleaning the area to be welded on the upper end surface of the orthotropic steel bridge deck and the rust, oil stains, paint and scale within the range of 20 to 30 mm on both sides, so as to expose the metallic luster;

[0061] S202. Place the U rib upside down on the orthotropic steel bridge deck. At this time, an assembly groove is formed between the bottom end of the U rib and the upper surface of the orthotropic steel bridge deck. The blunt edge of the groove is about 1.5mm, and the groove angle is about 60°, and the assembly gap between the U-rib and the orthotropic steel bridge deck is 0-0.75mm;

[0062] S203, using a solid welding wire to perform tack welding on the horizontal orthotropic steel bridge deck, the tack welding spacing is 300-400 mm, the tack welding length is 40-50 mm, and the tack welding ...

Embodiment 3

[0067] Embodiment 3 of the present invention is used for the double-side welding method of the U-rib unit weld seam is similar to Embodiment 2, the difference is that: the piece to be welded is a steel box girder bottom plate, the groove angle is 50°, and the tack welding in step 3 Using CO 2 Gas shielded welding, during step 4 fillet weld welding, adopt ternary mixed gas shielded welding, the mixed gas includes Ar, CO 2 and O 2 . The volume ratio of each component of the mixed gas is: Ar is 84%, CO 2 14%, O 2 2%. When the fillet weld is welded, the welding current is 270-290A, the arc voltage is 30-32V, and the welding speed is 360-400mm / min.

[0068] There is only a very small amount of silicon oxide slag on the surface of the solid wire gas shielded welding seam, which does not affect the online video monitoring of the appearance of the fillet weld inside the U rib. In addition, the ternary gas mixture (Ar+CO 2 +O 2 ) protection, the gas flow rate is 18 ~ 22L / min, w...

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Abstract

The invention provides a two-sided welding method for a U-shaped ribbed slab unit welding seam. The two-sided welding method comprises the following steps: cleaning the welding surface of a piece to be welded; placing a U-shaped rib on the surface of the piece to be welded, wherein an assembly groove is formed between the end part of a U-shaped ribbed web plate and the surface of the piece to be welded, and the groove angle is 50-60 degrees; carrying out positioning welding on the U-shaped rib and the piece to be welded in the horizontal position to obtain a U-shaped ribbed slab unit; welding a fillet welding seam at the jointing position of the inner side of the U-shaped ribbed web plate and the piece to be welded; and placing the U-shaped ribbed slab unit welded with the fillet welding seam on an anti-deformation slanting tension bed to carry out welding of an outer side welding seam, wherein a process of twin-wire submerged arc welding with single power supply is adopted. According to the two-sided welding method, a jointing welding seam between the U-shaped rib and the piece to be welded is changed into a two-sided fillet welding seam form from a single-sided fillet welding seam form in the prior art, so that stress amplitudes at a weld root and a weld toe are greatly lowered, the problem of initiation of fatigue cracks of the welding seam at the weld root is solved, and the fatigue performance at the weld toe is also improved.

Description

technical field [0001] The invention belongs to the manufacturing technology of steel structure bridges, and in particular relates to a double-sided welding method for U-rib unit welds. Background technique [0002] Steel box girders are generally composed of panel unit elements and floor unit elements. Orthotropic deck decks have the advantages of light weight and rapid construction, and are widely used in long-span bridges. All kinds of fatigue cracking problems of heterogeneous steel bridge decks are prominent, which has always troubled bridge builders. In the past few decades, researchers have gained a lot of experience and lessons, and carried out a lot of research work, aiming at improving and optimizing the welding details of orthotropic steel bridge deck, improving durability; but limited to the existing technology, U rib It can only be welded to the bridge deck from the outside. This kind of fillet weld is eccentric to the web of the rib. The bending stress of the ...

Claims

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Application Information

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IPC IPC(8): B23K9/16B23K9/18
CPCB23K9/16B23K9/18
Inventor 张华李立明孙雅洲高兴郭萍萍范泽平韩先斌
Owner WUCHUAN HEAVY ENG
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