Flatness control method for steel bridge support base plate

Abstract

The invention relates to a flatness control method for a steel bridge support base plate, which not only can effectively control deformation of a chord member bottom plate caused by welding of a web and a bottom plate weld joint, but also can prevent the middle of the support base plate from bulging caused by welding of a circumferential weld joint between the support base plate and the bottom plate. The method comprises the following steps: (1) assembling a reversible deformation stiffened plate on the back surface of a chord member bottom plate, then welding a welding seam of a web and the bottom plate by adopting a CO2 gas shielded welding method with relatively low linear energy, adopting a multi-layer multi-pass welding process during welding, and after the welding seam is naturally cooled to normal temperature, removing the reversible deformation stiffened plate, performing flame correction on the chord member bottom plate and emphatically controlling the planeness of the bottom plate; and (2) a plurality of plug welding holes are formed in the support base plate, then the support base plate is assembled on the chord member bottom plate, during welding, the plug welding holes are welded firstly, then circumferential weld joints of the support base plate are welded, finally, the plug welding holes are polished to be flat, and the flatness of the support base plate is detected.

Description

Technical Field

[0001] The invention relates to a method for controlling the flatness of a steel bridge bearing pad, which can effectively control the deformation of the chord bottom plate caused by welding the web plate and the bottom plate weld, and prevent the middle bulge of the bearing pad caused by welding the circumferential weld between the seat pad plate and the bottom plate. Background Art

[0002] The chord at the existing steel truss support is usually composed of a top plate, a partition plate, a web plate, a bottom plate, a support pad, etc. Figure 3 Steel bridges transfer loads to pier supports through bearing pads. In order to ensure close contact between the bearing pads and the supports, the flatness requirements of the bearing pads are relatively high. However, there are many welds here, which can easily lead to structural deformation and make the unevenness of the bearing pads exceed the standard. After analyzing the structural characteristics of the rods and the distribution of welds, it is believed that the deformation is caused by two factors. One is the deformation of the chord bottom plate caused by the welding of the web and the bottom plate, such as Figure 4 ; Second, when the circumferential weld between the support pad and the base plate is welded, a bulge is formed in the middle of the support pad. These two factors cause the unevenness of the support pad to seriously exceed the standard. Summary of the invention

[0003] Design purpose: To avoid the shortcomings of the background technology, a method for controlling the flatness of the steel bridge bearing pad is designed, which can effectively control the deformation of the chord bottom plate caused by the welding of the web and bottom plate welds, and prevent the bulge in the middle of the bearing pad caused by the welding of the circumferential weld between the seat pad and the bottom plate.

[0004] Design scheme: In order to achieve the above design objectives. The present invention comprehensively analyzes the structural characteristics of the chord rod at the support and the distribution law of the weld, and takes the following measures to control the welding deformation of the support pad: ⑴ After the box-type rod at the support is assembled, an anti-deformation stiffener is installed at the base plate support, and then a CO2 gas shielded welding method with a smaller line energy is used. During welding, a multi-layer and multi-pass welding process is used to reduce the welding deformation of the base plate. ⑵ When the support pad is assembled on the chord bottom plate, a plug welding hole with a diameter equal to or greater than φ50 is arranged on the support pad. During the welding operation, the plug welding hole is welded first, and then the surrounding weld of the support pad is welded to prevent deformation and bulging in the middle of the support pad.

[0005] Compared with the background technology, the present invention analyzes the structural characteristics of the chord rod and the distribution of the welds at the support, finds out the main cause of the unevenness, and then develops a control method for controlling the flatness of the support pad, so that the flatness of the support pad meets the specification requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the deformation of the chord bottom plate caused by the welding of the bottom plate weld seam controlled by the present invention.

[0007] Figure 2 It is a schematic diagram of a bulge in the middle of the support pad caused when the peripheral weld between the support pad and the base plate is controlled by the present invention.

[0008] Figure 3 It is a schematic diagram of the deformation of the chord bottom plate caused by the welding of the web and bottom plate in the background technology.

[0009] Figure 4 It is a schematic diagram of a bulge in the middle of a support pad caused by welding a circumferential weld between the support pad and the base plate in the background technology. DETAILED DESCRIPTION

[0010] Embodiment 1: A method for controlling the flatness of a steel bridge bearing pad. The chord at the steel truss beam bearing is usually composed of a top plate, a partition plate, a web plate, a bottom plate, a bearing pad, etc. After the chord box is assembled, an anti-deformation stiffener is assembled on the back of the chord bottom plate, and then the weld between the web plate and the bottom plate is welded. The welding process uses a CO 2 Gas shielded welding method, multi-layer and multi-pass welding process is used during welding. After the weld is naturally cooled to room temperature, the anti-deformation stiffener is removed, and the chord bottom plate is flame-corrected, with emphasis on controlling the flatness of the bottom plate. A plug welding hole of φ50mm or larger is processed in the middle area of ​​the support pad, and then the support pad is assembled to the chord bottom plate. When welding, the plug welding hole is welded first, and then the surrounding weld of the support pad is welded. Finally, the plug welding hole is polished flat, and the flatness of the support pad is tested.

[0011] It should be understood that although the above embodiments provide a relatively detailed textual description of the design ideas of the present invention, these textual descriptions are only simple textual descriptions of the design ideas of the present invention, rather than limitations on the design ideas of the present invention. Any combination, addition or modification that does not exceed the design ideas of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for controlling the flatness of a steel bridge bearing pad. The chord at the steel truss beam bearing is usually composed of a top plate, a diaphragm, a web, a bottom plate, and a bearing pad to form a chord box type, which is characterized by: 1) Assemble the anti-deformation stiffener on the back of the chord base plate, and then use the CO2 gas shielded welding method with low line energy to weld the weld between the web and the base plate. Use a multi-layer and multi-pass welding process. After the weld naturally cools to room temperature, remove the anti-deformation stiffener and flame correct the chord base plate, focusing on controlling the flatness of the base plate; 2) Arrange multiple plug welding holes on the support pad, and then assemble the support pad to the chord base plate. When welding, weld the plug welding holes first, then weld the surrounding weld of the support pad, and finally grind the plug welding holes to make them smooth, and check the flatness of the support pad.

2. The method for controlling the flatness of a steel bridge bearing pad according to claim 1 is characterized by: The diameter of the plug welding hole is equal to or greater than φ50mm.

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