Method for reinforcing tubular joint of existing cross-shaped circular steel tube by combining annular plate and longitudinal plate

Abstract

The invention discloses a method for reinforcing an existing cross-shaped round steel pipe tubular joint through combination of an annular plate and a longitudinal plate. The trapezoidal longitudinal plate is welded between a reinforced main pipe and a reinforced branch pipe; annular plates are welded to the positions, on the two sides of the branch pipe, of the outer wall of the main pipe, namely the branch pipe is divided into two semi-circular ring plates, the welding method is that the two semi-circular ring plates are welded to the outer surface of the main pipe, and the inner walls of the annular plates on the two sides of the branch pipe are welded to the outer wall of the main pipe and welded to the trapezoidal longitudinal plates in the side direction; an opening ring plate is welded at the joint of the reinforced main pipe and the reinforced branch pipe, the welding method is that the ring plate similar to a semi-circular ring is welded on the branch pipe and the main pipe at the intersecting line of the branch pipe and the main pipe, and a welding seam is in the axis direction of the branch pipe. The method is suitable for reinforcing the existing (served) cross-shaped steel pipe tubular joint, the axial and in-plane bending resistance and out-of-plane bending resistance bearing capacity of the steel pipe joint can be effectively enhanced at the same time, and it is guaranteed that a space structure has enough strength.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and construction, and relates to a method for combining a lateral ring plate and a trapezoidal longitudinal plate to reinforce a cross-shaped circular steel pipe intersecting node, which is suitable for reinforcing and repairing a cross-shaped steel pipe intersecting node in an existing spatial structure. Background Art

[0002] Steel tube structures have the advantages of superior mechanical properties, light weight, low cost, simple and beautiful appearance, etc., and are widely used in medium and high-rise structures, bridges and other fields. In recent years, with the large-scale application of steel tube structures, some problems have also occurred in the nodes between steel tube components during construction and use. As the most commonly used direct welding connection method in steel tube structures (i.e., intersecting connection nodes), stress concentration and residual stress often occur in the weld area, and the node bearing capacity is relatively low (in most cases, lower than the bearing capacity of adjacent components). In addition, some steel tube intersecting nodes built in the early 21st century are also facing unfavorable conditions such as local corrosion caused by long-term service; with the development of green new energy strategies, some large-span space structures need to install photovoltaic power generation systems on the roof, etc., resulting in greater loads on the steel tube intersecting nodes in the structure. These situations urgently need to strengthen the bearing capacity of the node area of the steel tube structure. In order to reinforce the existing steel tube structure with intersecting nodes, several reinforcement methods for steel tube nodes have been proposed, such as welding stiffening plates on the outside of the steel tube, welding stiffening ribs inside, bolt reinforcement, and pouring concrete inside the steel tube. However, compared with several reinforcement methods, internal pouring of concrete increases the deadweight of the node, and it is necessary to groove the existing steel pipes in service, which will damage the steel pipes during cutting and grooving, making the construction difficult; internal welding stiffening ribs are difficult to apply to the reinforcement of existing (in-service) steel pipe structures. Comprehensively comparing several reinforcement methods, external welding of stiffening plates has the advantages of convenient construction and good reinforcement effect.

[0003] For the existing cross-shaped nodes, which are often used in spatial steel pipe structures such as single-layer lattice shells, the branch pipes (web members) in the nodes are often subjected to the combined effects of axial force, out-of-plane bending moment, and in-plane bending moment. The existing external welded stiffening plate reinforcement method, such as welding longitudinal stiffening plates at the nodes or welding stiffening rings on the periphery of the main pipe (chord), only has a reinforcement effect on one of the internal forces (loads), which has limitations in actual use and needs to be improved. Summary of the invention

[0004] In order to overcome the deficiencies of the existing technologies, the present invention provides a method for combining longitudinal plates and ring plates to reinforce the cruciform circular steel pipe intersecting joints. Based on the original cruciform steel pipe intersecting joints, first, a ring plate in the shape of an approximate semi-circle (composed of two semi-circular ring plates) is welded to the branch pipe and the main pipe at the intersecting line of the branch pipe and the main pipe, and the weld seam is along the axis of the branch pipe; then, trapezoidal longitudinal plates (a total of four pieces) are welded to the main pipe and the branch pipe respectively with two adjacent sides; finally, a ring plate (divided into two semi-circular ring plates) is welded to the side of the trapezoidal plate far from the main pipe, and the inner wall of the ring plate is welded to the outer wall of the main pipe (chord member), ultimately forming the effect of combining three ring plates (each ring plate is a semi-circular ring plate) and four longitudinal plates to reinforce the steel pipe joint. This method is applicable to the reinforcement of existing (already in service) cruciform steel pipe intersecting joints, and can effectively enhance the axial, in-plane bending, and out-of-plane bending bearing capacities of the steel pipe joints simultaneously, ensuring that the space structure has sufficient strength.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] A method for combining ring plates and longitudinal plates to reinforce existing cruciform circular steel pipe intersecting joints, in which trapezoidal longitudinal plates are welded between the main pipe and the branch pipe to be reinforced; ring plates are welded to the outer walls of the main pipes on both sides of the branch pipe, that is, divided into two semi-circular ring plates, and the welding method is to weld two semi-circular ring plates on the outer surface of the main pipe, where the inner walls of the ring plates on both sides of the branch pipe are welded to the outer wall of the main pipe and are welded to the trapezoidal longitudinal plates laterally; an open-ring plate is welded at the joint of the main pipe and the branch pipe to be reinforced, and the welding method is to weld a ring plate in the shape of an approximate semi-circle to the branch pipe and the main pipe at the intersecting line of the branch pipe and the main pipe, and the weld seam is along the axis direction of the branch pipe.

[0007] Furthermore, fillet welds are used for welding between the main pipe to be reinforced and the longitudinal plates, between the branch pipe and the longitudinal plates, between the main pipe and the ring plates, between the joint and the ring plates, and between the ring plates and the longitudinal plates.

[0008] Still further, the main pipe and the branch pipe in the joint area to be reinforced are circular steel pipes, that is, the joint to be reinforced is a circular steel pipe intersecting joint; the planar shape of the longitudinal plates used for reinforcement is trapezoidal, the planar shape of the ring plates used for reinforcement is circular, and the planar shape of the ring plates used for reinforcement at the joint is an open ring.

[0009] Even further, the longitudinal plates and ring plates used for reinforcement are made of steel with a yield strength similar to that of the main pipe of the joint to be reinforced; the thicknesses of the longitudinal plates and the ring plates are taken to be equal to or slightly greater than the wall thickness of the main pipe of the joint to be reinforced.

[0010] The beneficial effects of the present invention are mainly manifested in that: this method is applicable to the reinforcement of existing welded steel pipe intersecting joints, can effectively improve the bearing capacity of the steel pipe joints, enhance the strength of the overall frame structure, and is convenient for construction. Description of the Drawings

[0011] Figure 1Overall schematic diagram of the combined reinforcement joint

[0012] Figure 2 Detail structural schematic diagram of the combined reinforcement joint. Among them, (a) represents the elevation view of the combined reinforcement joint, and (b) represents the side view of the combined reinforcement joint. 1 is the original branch pipe of the joint, 2 is the original main pipe of the joint, 3 is the ring plates on both sides of the branch pipe (a total of four semi-circular ring plates on both sides), 4 is the ring plate at the intersection line of the joint area (two approximately semi-circular ring plates), and 5 is the trapezoidal longitudinal plate.

[0013] Figure 3 Detail structural schematic diagram of the stiffening plate. Among them, (a) represents the ring plate at the intersection line of the joint area, (b) represents the ring plates on both sides of the branch pipe, and (c) represents the trapezoidal longitudinal plate.

[0014] Figure 4 Load-displacement comparison diagram of the branch pipes in the reinforced joint and circular joint under axial compression

[0015] Figure 5 Moment-rotation angle comparison diagram of the branch pipes in the reinforced joint and circular joint under in-plane bending moment

[0016] Figure 6 Moment-rotation angle comparison diagram of the branch pipes in the reinforced joint and circular joint under out-of-plane bending moment Specific implementation method

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] Refer to Figures 1 to 6 , a method for combining ring plates and longitudinal plates to reinforce existing cruciform circular steel pipe intersecting joints. Weld trapezoidal longitudinal plates between the main pipe and the branch pipe to be reinforced; weld annular plates on the outer walls of the main pipes on both sides of the branch pipe, that is, divide them into two semi-circular ring plates. The welding method is to weld two semi-circular ring plates on the outer surface of the main pipe. The inner walls of the ring plates on both sides of the branch pipe are welded to the outer wall of the main pipe and are welded to the trapezoidal longitudinal plate laterally; weld open-ring plates at the joints of the main pipe and the branch pipe to be reinforced. The welding method is to weld approximately semi-circular ring plates to the branch pipe and the main pipe at the intersection line of the branch and main pipes, and the weld seam is along the axis direction of the branch pipe.

[0019] In this embodiment, the joint to be reinforced includes the main pipe 2 and the branch pipe 1 of the original joint. First, weld the two adjacent sides of the trapezoidal longitudinal plates 5 (a total of four) to the main pipe and the branch pipe respectively, then weld the ring plates 3 (two approximately semi-circular ring plates) at the intersection line of the joint area to the main pipe and the branch pipe respectively, and finally weld the ring plates 4 (a total of four semi-circular ring plates on both sides) on both sides of the branch pipe to the outer wall of the main pipe, and their sides are welded to the trapezoidal longitudinal plates 5.

[0020] The angle welds are used for welding between the reinforced main pipe and the longitudinal plate, between the branch pipe and the longitudinal plate, between the main pipe and the ring plate, between the node and the ring plate, and between the ring plate and the longitudinal plate.

[0021] The reinforced branch pipe 1 is a circular steel pipe, and the reinforced main pipe 2 is a circular steel pipe; the plane shape of the longitudinal plate used for reinforcement is trapezoidal, and the plane shape of the ring plate used for reinforcement is circular or approximately semi-circular.

[0022] The longitudinal plate and the ring plate used for reinforcement are made of steel with a yield strength similar to that of the main pipe of the reinforced node; the thickness of the longitudinal plate and the ring plate is taken to be equal to or slightly greater than the wall thickness of the main pipe of the reinforced node.

[0023] The content described in the embodiments of this specification is only a list of the implementation forms of the inventive concept and is only for illustrative purposes. The protection scope of the present invention should not be regarded as limited to the specific forms stated in this embodiment, and the protection scope of the present invention also extends to equivalent technical means that can be conceived by those of ordinary skill in the art based on the inventive concept of the present invention.

Claims

1. A method for combining a ring plate and a longitudinal plate to reinforce an existing cruciform circular steel tube intersecting joint, characterized in that, Weld trapezoidal longitudinal plates between the reinforced main pipe and the branch pipes; weld annular plates at the outer walls of the main pipe on both sides of the branch pipes, that is, divide them into two semi-annular plates. The welding method is to weld two semi-circular annular plates on the outer surface of the main pipe. The inner walls of the annular plates on both sides of the branch pipe are welded to the outer wall of the main pipe, and are welded to the trapezoidal longitudinal plates laterally; weld open annular plates at the joints of the reinforced main pipe and the branch pipes. The welding method is to weld an annular plate similar to a semi-circle to the branch pipe and the main pipe at the intersection line of the branch pipe and the main pipe, and the weld seam is along the axis direction of the branch pipe.

2. The method for combining and strengthening an existing cruciform circular steel tube intersecting joint by using an annular plate and a longitudinal plate as claimed in claim 1, characterized in that, Fillet welds are used for welding between the reinforced main pipe and the longitudinal plate, between the branch pipe and the longitudinal plate, between the main pipe and the annular plate, between the joint and the annular plate, and between the annular plate and the longitudinal plate.

3. The method for combining and strengthening an existing cruciform circular steel tube penetrator node with an annular plate and a longitudinal plate as claimed in claim 1 or 2, characterized in that, The main pipe and the branch pipe of the reinforced joint area are circular steel pipes, that is, the reinforced joint is a circular steel pipe intersecting joint; the plane shape of the longitudinal plate used for reinforcement is trapezoidal, the plane shape of the annular plate used for reinforcement is circular, and the plane shape of the annular plate used for reinforcement at the joint is an open ring.

4. The method for combining the ring plate and the longitudinal plate to reinforce the existing cruciform circular steel tube intersecting joints as claimed in claim 1 or 2, characterized in that, The longitudinal plate and the annular plate used for reinforcement are made of steel with a yield strength similar to that of the main pipe of the reinforced joint; the thickness of the longitudinal plate and the annular plate is taken to be equal to or slightly greater than the wall thickness of the main pipe of the reinforced joint.

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