Closed steel tube support section punch bolt connection node and its processing method

Abstract

The application discloses a closed steel pipe support split punch bolt connection node and a processing method thereof. The original steel pipe section, transition section and end cap section of the steel pipe support are formed by punching a same closed steel pipe. An axial split is arranged at the pipe end relative to the middle part of the pipe wall, and a crack stopping hole is arranged at the root of the split. The pipe wall on both sides of the split is symmetrically punched to form a pair of groove structures on both sides of the node plate. Each groove structure comprises a flat connecting wing attached to the node plate and a bending-resistant groove section protruding away from the node plate. The node plate is connected to the steel pipe support along the split. A plurality of high-strength bolts are arranged to connect the flat connecting wing and the node plate along the support axis. During processing, a steel wedge die is used to expand the joint, and a cross-shaped punch die section is used in cooperation with a relative groove-shaped outer die to be punched and formed. The application solves the problems of on-site welding, force transmission eccentricity, insufficient pipe end plane outer stiffness and inconvenient disassembly in the end connection of the closed steel pipe support. The application only needs split and cold working actions of punching, and has limited cost and good economy.

Description

Technical Field

[0001] This invention relates to the field of steel structure connection technology in building engineering, and more specifically, to a closed steel pipe support slit punched bolt connection node and its processing method. Background Technology

[0002] Steel frame structures typically incorporate diagonal bracing within the frame plane to enhance lateral stiffness. This diagonal bracing primarily bears axial forces, and its compressive stability is often a key design factor. Closed-section steel pipes, with their large radius of gyration, are suitable as diagonal bracing members; however, their closed cross-section makes direct assembly and connection of the ends to gusset plates difficult.

[0003] The existing method for connecting the steel pipe support end to the gusset plate is to cut a groove and then weld it on-site along the intersection line of the groove and the gusset plate. This method can provide the pipe end with some out-of-plane constraint from the gusset plate, but it relies on on-site welding, which is not conducive to prefabricated construction, and it is difficult to disassemble and reassemble when replacing damaged supports after an earthquake.

[0004] To achieve a fully bolted connection, the end of the steel pipe can be flattened and then holes drilled for bolting, or additional connecting parts such as end plates and lugs can be welded to the pipe end. Flattening the entire pipe will significantly reduce the effective height of the pipe end section, thereby weakening the out-of-plane bending resistance of the node plate; using additional connecting parts increases the number of welds and components, and if assembled with pins, the initial rotational constraint of the connection may be weakened due to assembly gaps.

[0005] Therefore, a node is needed that can achieve a fully bolted connection between the steel pipe support and the gusset plate without welding additional plates, so that the gusset plate is located at the center of the steel pipe support for force transmission, and the pipe end retains a cross-sectional height that can withstand out-of-plane bending, while using multiple sets of axially distributed bolts to form in-plane rotation constraints. Summary of the Invention

[0006] The purpose of this invention is to solve the problems mentioned in the background art. This invention provides a closed-end steel pipe support slit stamping bolt connection node and its processing method to solve the problems of field welding, force transmission eccentricity, insufficient out-of-plane stiffness of the pipe end, and inconvenience of disassembly and assembly in the connection of the closed-end steel pipe support.

[0007] The present invention adopts the following technical solution:

[0008] A closed-end steel pipe support with slit stamped bolt connection node includes a steel pipe support and a node plate. The steel pipe support comprises, along the axial direction, a main steel pipe section, a transition section, and an end cap-shaped section, all formed by stamping from the same closed-end steel pipe. The steel pipe support has slits extending axially from its end face to the transition section in the middle of opposite sections of its end wall. The end cap-shaped section is formed symmetrically by stamping the pipe walls on both sides of the slits, and consists of a pair of groove-shaped structures located on both sides of the node plate. Each groove-shaped structure includes components related to the end cap-shaped section. The node plate has a flat connecting wing that fits against it and a bending groove protruding from the flat connecting wing in a direction away from the node plate. The pair of groove structures are symmetrical about the mid-plane of the node plate. The node plate is connected to the steel pipe support at the cut, and the mid-plane of the node plate passes through the longitudinal axis of the steel pipe support. The pair of flat connecting wings and the node plate are respectively provided with at least two sets of bolt holes arranged at intervals along the axial direction of the steel pipe support. Each set of high-strength bolts passes through the flat connecting wing on one side, the node plate, and the flat connecting wing on the other side in sequence and is fastened.

[0009] The cutting plane containing the slit is perpendicular to the plane containing the longitudinal weld of the closed steel pipe, and the slit is located in the middle of the steel pipe cross-section, so that the pipe wall after the slit is symmetrical about the cutting plane.

[0010] Furthermore, each of the slits has an arc-shaped anti-crack hole at its root, and the axial depth of the slit is equal to the sum of the axial lengths of the transition section and the end cap-shaped section.

[0011] Furthermore, each set of bolt holes includes bolt holes located on both sides of the longitudinal axis of the steel pipe support, so that at least two sets of high-strength bolts together constrain the steel pipe support to rotate in the plane relative to the node plate.

[0012] Furthermore, the design bearing capacity of the node plate and the design bearing capacity of the bolt group composed of the high-strength bolts are both greater than the full-section plastic bearing capacity of the steel pipe support.

[0013] Furthermore, the node plate is connected to the steel column, and the steel beam, steel column and node plate are connected by bolts and / or welding.

[0014] Furthermore, the closed-end steel pipe is a round steel pipe or a rectangular steel pipe.

[0015] The present invention also provides a processing method for the above-mentioned nodes, comprising the following steps:

[0016] First, an axial slit is cut in the middle of the opposite pipe wall at the end of the closed steel pipe, and an arc-shaped anti-crack hole is formed at the root of the slit. Then, a steel wedge mold is pressed into the slit until the tip of the steel wedge corresponds to the anti-crack hole to symmetrically enlarge the slit. Next, the cross-shaped stamping die section is placed inside the pipe end, and a pair of groove-shaped outer molds are symmetrically placed outside the pipe end. The straight connecting wing and the bending groove section are formed by the cooperation of the inner and outer molds. Finally, at least two sets of bolt holes are machined on the straight connecting wing.

[0017] The steel wedge segment is a frustum with an isosceles triangle cross-section. The axial height of the frustum is greater than the cross-sectional height of the closed steel pipe. The height of the isosceles triangle is equal to the axial length of the transition segment. The width of the base of the isosceles triangle is greater than the thickness of the node plate.

[0018] Furthermore, the cross section of the stamping die section is cross-shaped and has chamfers at each corner. The thickness of the cross-shaped cross section in one direction is the same as the bottom width of the steel wedge section, and the height in the other direction is less than the sum of the bottom width of the steel wedge section and the inner diameter of the closed steel pipe. The pair of groove-shaped outer dies are located on opposite sides of the end of the steel pipe and apply pressure symmetrically.

[0019] Beneficial effects

[0020] (1) The end cap-shaped section is directly formed by cutting, widening and stamping the original closed steel pipe. There is no need to weld additional end plates or ear plates, avoiding on-site welding and facilitating support installation, disassembly and replacement, which is in line with the design concept of "urban mine".

[0021] (2) By using the central cut and symmetrical stamping to position the node plate at the center of the steel pipe support, the additional internal force caused by the connection eccentricity can be reduced.

[0022] (3) The end is not flattened as a whole, and the bending groove retains the effective height of the pipe end section; this structure, together with multiple sets of bolts set along the axial direction, provides the out-of-plane bending resistance and in-plane rotation constraint of the node plate respectively.

[0023] (4) The present invention only requires cold working actions of cutting and stamping, and basically does not require processing costs, so the cost is extremely limited and the economy is good. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of the closed-end steel pipe support section punched bolt connection node of the present invention;

[0025] Figure 2 This is a schematic diagram of the beam-column joint structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the slit-punched round steel pipe support of the present invention;

[0027] Figure 4This is a schematic diagram of the structure of the slit-punched rectangular steel pipe support of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the steel wedge mold of the present invention;

[0029] Figure 6 This is a schematic diagram of the cross-cutting process at the end of the circular steel pipe support of the present invention;

[0030] Figure 7 This is a schematic diagram of the cross-cutting process at the end of the rectangular steel pipe support of the present invention;

[0031] Figure 8 This is a schematic diagram of the steel wedge expansion process at the end of the circular steel pipe support of the present invention;

[0032] Figure 9 This is a schematic diagram of the steel wedge expansion process at the end of the rectangular steel pipe support of the present invention;

[0033] Figure 10 This is a schematic diagram of the combined die stamping process for the end of the circular steel pipe support of the present invention;

[0034] Figure 11 This is a schematic diagram of the combined die stamping process for the rectangular steel pipe support end of the present invention;

[0035] Figure 12 This is a schematic diagram of the on-site installation process of the steel pipe support node of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] As shown in the figure, this invention discloses a closed-end steel pipe support with a punched bolt connection node, which is set in the beam-column joint area formed by a steel column 1 and a steel beam 2. The steel pipe support 3 is connected to the node plate 4 by high-strength bolts 5. In the figure, the steel column 1 is a square steel pipe column, and the steel beam 2 is shown as an H-shaped steel beam; the steel beam 2, steel column 1, and node plate 4 can be connected by conventional bolts and / or welding. The side of the node plate 4 facing the steel beam 2 has an inward-receding edge to leave space for the rotation and positioning of the steel pipe support 3 and the installation of bolts. The node plate 4 and steel column 1 ensure the connection strength, facilitate the assembly of the diagonal brace by rotation, and transmit more of the force of the diagonal brace to the steel column 1, which conforms to the structural stress.

[0038] like Figure 3 and Figure 4As shown, the steel pipe support 3, from the side furthest from the node plate 4 to the connecting end, sequentially includes the original steel pipe section 3-1, the transition section 3-2, and the end cap-shaped section 3-3. All three sections are formed by stamping from the same closed-end steel pipe, without welding additional end plates, ear plates, or slotted connectors to the pipe ends. The original steel pipe section 3-1 maintains the original closed-end cross-section; the transition section 3-2 continuously transitions between the original closed-end cross-section and the end cap-shaped section 3-3; the end cap-shaped section 3-3 is a connecting section formed by plastic stamping of the pipe wall.

[0039] At one connection end, the steel pipe support 3 has slits 9 extending axially along the middle of its opposite pipe wall, allowing the gusset plate 4 to enter the pipe end through the slits 9. The slits 9 are located in the middle of the cross-section, and the cutting plane of the slits 9 is perpendicular to the plane of the longitudinal weld 8 of the steel pipe. The root of the slits 9 is located in the transition section 3-2, and an arc-shaped anti-crack hole 6 is provided to limit the extension position of the slits 9 and reduce stress concentration at the root of the cut. The depth of the slits 9 is equal to the sum of the lengths of the transition section 3-2 and the end cap-shaped section 3-3.

[0040] The end cap-shaped section 3-3 includes a pair of symmetrical groove structures about the mid-plane of the node plate 4. Each groove structure includes a straight connecting wing 3-3-1 and a bending-resistant groove section 3-3-2. The straight connecting wing 3-3-1 fits against the surface of the node plate 4 and is used to arrange bolt holes 3-3-1-1 and transmit axial force; the bending-resistant groove section 3-3-2 protrudes from the straight connecting wing 3-3-1 in a direction away from the node plate 4, so that the pipe end still has a non-zero cross-sectional height in the thickness direction of the node plate 4. Thus, while achieving bolt connection at the pipe end, it is not necessary to make the cross-sectional height of the pipe end essentially disappear as in an integral flattening connection.

[0041] The gusset plate 4 is located between a pair of straight connecting wings 3-3-1 at the section 9, with its mid-surface passing through the longitudinal axis of the steel pipe support 3. At least two sets of bolt holes are provided on the pair of straight connecting wings 3-3-1 and the gusset plate 4, with each set of bolt holes spaced apart along the axial direction of the steel pipe support 3. Each set of bolt holes may include holes located on both sides of the longitudinal axis of the steel pipe support 3. After installation, high-strength bolts 5 are sequentially passed through one side of the straight connecting wing 3-3-1, the gusset plate 4, and the other side of the straight connecting wing 3-3-1 and tightened, so that at least two sets of high-strength bolts 5 form a bolt group capable of constraining rotation within the node plane.

[0042] The dimensions and quantity of the gusset plate 4 and the bolt group are determined according to the structural design requirements, ensuring that the design bearing capacity of both the gusset plate 4 and the bolt group is greater than the full-section plastic bearing capacity of the steel pipe support 3. The diameter, spacing, edge distance of the bolt holes, and the length of the end cap section 3-3 are determined based on the steel pipe cross-section, the thickness of the gusset plate, and the bearing requirements; this invention does not limit the specific values.

[0043] The ends of the steel pipe support 3 can be processed using steel wedge molds 7 and outer molds 10. The steel wedge mold 7 includes a steel wedge section 7-1 and a stamping die section 7-2. The steel wedge section 7-1 is a frustum with an isosceles triangular cross-section, its axial height being greater than the height of the steel pipe cross-section. The height of the isosceles triangle corresponds to the length of the designed transition section 3-2, and the width of the base of the isosceles triangle is greater than the thickness of the node plate 4. The stamping die section 7-2 has a cross-shaped cross-section with chamfered corners. The thickness of the cross-shaped cross-section in one direction is the same as the width of the base of the steel wedge section 7-1, while its height in the other direction is less than the sum of the width of the base of the steel wedge section 7-1 and the inner diameter of the steel pipe. The outer mold 10 is a channel-shaped mold, and they are arranged symmetrically in pairs.

[0044] During processing, first press Figure 6 or Figure 7 An axial cut 9 is formed in the middle of the opposite pipe wall at the end of the steel pipe. The cut 9 extends to the predetermined transition section 3-2, and an arc-shaped anti-crack hole 6 is machined at its root. During cutting, the cutting plane is made perpendicular to the plane where the longitudinal weld 8 is located to maintain the symmetry of the pipe wall after the cut.

[0045] Then press Figure 8 or Figure 9 The steel wedge segment 7-1 of the steel wedge mold 7 is pressed into the end face of the steel pipe along the slit 9. As the steel wedge segment 7-1 enters, the pipe walls on both sides of the slit 9 expand symmetrically; when the tip of the steel wedge segment 7-1 corresponds to the crack arresting hole 6, the pressing is stopped, so that the expansion range corresponds to the predetermined transition section 3-2.

[0046] Press again Figure 10 or Figure 11 The cross-shaped stamping die section 7-2 is held inside the expanded steel pipe end, and a pair of grooved outer dies 10 are arranged on opposite sides of the steel pipe end. The inner and outer dies symmetrically cooperate to apply pressure, causing the expanded pipe wall to be plastically formed around the stamping die section 7-2 into a straight connecting wing 3-3-1 and a bending groove section 3-3-2. Chamfers at the die corners are used to ensure a smooth transition of the pipe wall during forming. The forming dimensions are determined based on the steel used and the pipe wall thickness, taking into account springback deformation after unloading. After stamping, at least two sets of bolt holes are machined on the straight connecting wing 3-3-1. If the other end of the steel pipe support 3 uses the same node, the above processing is repeated on the other end.

[0047] like Figure 12 As shown, during on-site installation, first hoist the steel pipe support 3 into the frame plane, ensuring its end is within the rotatable space between the node plate 4 and the adjacent steel beam 2; then rotate the steel pipe support 3 within the frame plane, so that the node plate 4 enters between a pair of straight connecting wings 3-3-1 along the cut 9, aligning the bolt holes on the node plate 4 with the bolt holes on the straight connecting wings 3-3-1; finally, install and tighten the high-strength bolts 5. When removing or replacing the steel pipe support 3, the operation can be performed in reverse order.

[0048] Figure 3 and Figure 4 The end structures of round and rectangular steel pipes are shown respectively. Both types of closed sections adopt the forming approach of relative central slits, steel wedge expansion, and symmetrical groove stamping. For different closed sections, it is only necessary to make the working surfaces of the steel wedge mold 7 and the outer mold 10 fit with the inner and outer walls of the corresponding steel pipes, without changing the technical relationship of centered node plates, bolted straight connecting wings, and the retention of section height in the bending groove section.

[0049] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A closed-end steel pipe support with a slit and stamped bolt connection node, characterized in that, The steel pipe support (3) includes a steel pipe support (3) and a node plate (4). The steel pipe support (3) includes, along the axial direction, a main steel pipe section (3-1), a transition section (3-2), and an end cap-shaped section (3-3). The main steel pipe section (3-1), the transition section (3-2), and the end cap-shaped section (3-3) are formed by stamping the same closed steel pipe. The middle portion of the opposite pipe wall at the end of the steel pipe support (3) is provided with a slit (9) extending axially from the end face to the transition section (3-2). The end cap-shaped section (3-3) is formed by symmetrical stamping of the pipe walls on both sides of the slit (9) and has a pair of groove-shaped structures located on both sides of the node plate (4). Each groove-shaped structure includes a straight connecting wing (3-1) that fits against the node plate (4). 3-1) and a bending groove section (3-3-2) protruding from the straight connecting wing (3-3-1) in a direction away from the node plate (4), the pair of groove structures are symmetrical about the mid-plane of the node plate (4); the node plate (4) is connected to the section (9) of the steel pipe support (3), and the mid-plane of the node plate (4) passes through the longitudinal axis of the steel pipe support (3); the pair of straight connecting wings (3-3-1) and the node plate (4) are respectively provided with at least two sets of bolt holes arranged at intervals along the axial direction of the steel pipe support (3), and each set of high-strength bolts (5) passes through the straight connecting wing (3-3-1) on one side, the node plate (4) and the straight connecting wing (3-3-1) on the other side in sequence and is fastened.

2. The closed-end steel pipe support slit stamped bolt connection node according to claim 1, characterized in that, The cutting plane where the cut (9) is located is perpendicular to the plane where the longitudinal weld (8) of the closed steel pipe is located, and the cut (9) is located in the middle of the steel pipe section, so that the pipe wall after the cut is symmetrical about the cutting plane.

3. The closed-end steel pipe support slit stamped bolt connection node according to claim 2, characterized in that, Each of the cuts (9) has an arc-shaped anti-crack hole (6) at its root, and the axial depth of the cut (9) is equal to the sum of the axial lengths of the transition section (3-2) and the end cap section (3-3).

4. The closed-end steel pipe support slit stamped bolt connection node according to claim 1, characterized in that, Each set of bolt holes includes bolt holes located on both sides of the longitudinal axis of the steel pipe support (3), so that at least two sets of high-strength bolts (5) together constrain the steel pipe support (3) to rotate in the plane relative to the node plate (4).

5. A closed-end steel pipe support slit stamped bolt connection node according to claim 1, characterized in that, The design bearing capacity of the node plate (4) and the design bearing capacity of the bolt group composed of each of the high-strength bolts (5) are both greater than the full-section plastic bearing capacity of the steel pipe support (3).

6. The closed-end steel pipe support slit stamped bolt connection node according to claim 1, characterized in that, The node plate (4) is connected to the steel column (1), and the steel beam (2), steel column (1) and node plate (4) are connected by bolts and / or welding.

7. A closed-end steel pipe support slit stamped bolt connection node according to claim 1, characterized in that, The closed-end steel pipe is either a round steel pipe or a rectangular steel pipe.

8. A method for processing a closed-end steel pipe support with a slit and stamped bolt connection node, characterized in that, Includes the following steps: A axial cut is made along the middle of the opposite pipe wall at the end of the closed steel pipe to form mutually aligned cuts (9), such that the axial depth of the cut (9) is equal to the sum of the axial lengths of the transition section (3-2) to be formed and the end cap section (3-3), and an arc-shaped anti-crack hole (6) is formed at the root of the cut (9). The steel wedge segment (7-1) of the steel wedge mold (7) is pressed into the end face of the closed steel pipe along the slit (9) until the tip of the steel wedge segment (7-1) corresponds to the crack-stopping hole (6) to symmetrically enlarge the slit (9). The cross-shaped stamping die section (7-2) of the steel wedge die (7) is located inside the end of the expanded steel pipe, and a pair of grooved outer dies (10) are symmetrically arranged on the outside of the end of the steel pipe. The stamping die section (7-2) and the pair of grooved outer dies (10) work together to apply pressure, so that the pipe wall at the end of the steel pipe is plastically formed into a pair of grooved structures with straight connecting wings (3-3-1) and bending groove section (3-3-2); At least two sets of bolt holes (3-3-1-1) are machined on the straight connecting wing (3-3-1) at intervals along the axial direction of the steel pipe.

9. A processing method for a closed-end steel pipe support slit stamped bolt connection node according to claim 8, characterized in that, The steel wedge segment (7-1) is a frustum with an isosceles triangle cross-section. The axial height of the frustum is greater than the cross-sectional height of the closed steel pipe. The height of the isosceles triangle is equal to the axial length of the transition segment (3-2). The width of the base of the isosceles triangle is greater than the thickness of the node plate (4).

10. A processing method for a closed-end steel pipe support slit stamped bolt connection node according to claim 8, characterized in that, The cross section of the stamping die section (7-2) is cross-shaped and has chamfers at each corner. The thickness of the cross-shaped cross section in one direction is the same as the bottom width of the steel wedge section (7-1), and the height in the other direction is less than the sum of the bottom width of the steel wedge section (7-1) and the inner diameter of the closed steel pipe. The pair of groove-shaped outer dies (10) are located on opposite sides of the end of the steel pipe and apply pressure symmetrically.

Images