Steel structure building beam column assembly type node in booster station

Abstract

The invention provides a steel structure building beam column assembly type joint in a booster station, and belongs to the technical field of low multi-story building assembly type steel structures. The composite hole comprises an upper leading-in hole, a lower locking hole and a rectangular sliding groove for communicating the two holes; the in-column diaphragm plate is arranged in the square steel pipe column and is welded and fixed with the inner wall of the square steel pipe column, and an inner convex shear key is welded on the surface of one side, facing the composite hole, of the in-column diaphragm plate; the T-shaped connecting piece comprises a vertical plate and a horizontal plate, the vertical plate and the horizontal plate are vertically welded to form an integral T-shaped component, and a groove matched with the inner convex shear key is formed in the inner side surface of the vertical plate; a high-strength bolt connection pair solves the technical problems that a bolt cannot penetrate through the interior due to the closed section of a square steel pipe column, the integrity of the section of the column is weakened through traditional external connection, and the bolt is prone to brittle failure under the combined action of shearing and pulling.

Description

Technical Field

[0001] This invention belongs to the technical field of prefabricated steel structure for low-rise and multi-story buildings. Specifically, it relates to a prefabricated joint for beams and columns in a substation steel structure building. Background Technology

[0002] With the continuous deepening of industrialized and prefabricated construction models, steel structures are playing an increasingly important role in modern buildings due to their advantages such as high strength, rapid construction, and recyclable materials. As a critical infrastructure of the power system, substations have stringent requirements for safety, durability, and construction efficiency in their internal steel structure buildings. Beam-column joints, as the core components in steel structures that transmit bending moments and shear forces, directly affect the overall structural mechanical behavior, stability, and seismic resistance. They also relate to construction and assembly efficiency and life-cycle costs, making them an important research topic in the field of steel structure engineering.

[0003] Currently, steel beam-column connections in substations primarily employ two methods: welding and bolting. Welding connections are easily automated under factory prefabrication conditions, producing continuous, uniform welds with reliable mechanical properties. However, on-site welding is constrained by factors such as the construction environment and the skill level of personnel, resulting in significant quality fluctuations and low efficiency. In contrast, bolting connections offer a high degree of prefabrication and strong adaptability to construction conditions, better aligning with the "modular assembly" construction logic of prefabricated buildings. However, for closed-section components like square steel tube columns, traditional bolting technology faces significant technical bottlenecks: the closed section of square steel tube columns results in limited internal space, preventing bolts from being inserted through the column, leading to extremely poor on-site installation operability; existing external connection structures often require large handholes in the column wall or complex segmented assembly processes, severely weakening the integrity of the column section and reducing the load-bearing capacity and fatigue resistance of the joint; furthermore, bolts in traditional joints typically bear the combined effects of shear and tension, making them prone to brittle shear failure under strong earthquakes, exhibiting insufficient ductility and failing to meet the high seismic fortification requirements of important power facilities such as substations. Summary of the Invention

[0004] In view of this, the present invention provides a prefabricated beam-column joint for steel structure buildings in a booster station, which solves the technical problems that the closed section of the square steel tube column makes it impossible for bolts to be inserted from the inside, the traditional external connection weakens the integrity of the column section, and the bolts are prone to brittle failure under the combined action of shear and tension.

[0005] This invention is implemented as follows:

[0006] This invention provides a prefabricated beam-column joint for a steel structure building within a substation, comprising:

[0007] The square steel tube column has pre-fabricated composite holes on its sidewalls. The composite holes include an upper inlet hole, a lower locking hole, and a rectangular groove connecting the two holes. The diameter of the inlet hole is larger than the diameter of the locking hole.

[0008] An internal diaphragm is provided inside the square steel tube column and welded to the inner wall of the square steel tube column. An internal convex shear key is welded to the side surface of the internal diaphragm facing the composite hole. The position of the internal convex shear key corresponds to the locking hole and extends into the locking hole to form a fixed fit.

[0009] The T-shaped connector includes a vertical plate and a horizontal plate. The vertical plate and the horizontal plate are welded perpendicularly to form an integral T-shaped component. The outer surface of the vertical plate is attached to the outer wall of the square steel tube column. The inner surface of the vertical plate is provided with a groove that matches the inner convex shear key. The end of the horizontal plate away from the vertical plate is connected to the H-shaped steel beam by bolts.

[0010] The high-strength bolt connection pair has its bolt shank passing sequentially through the mounting hole on the vertical plate, the locking hole, and the corresponding hole on the transverse diaphragm inside the column, fastening the T-shaped connector to the square steel pipe column. The inner convex shear key and the groove fit together to form a shear force transmission structure, bearing the horizontal shear force at the node.

[0011] The technical advantages of the prefabricated beam-column joint for steel structure buildings in substations provided by this invention are as follows: Through the interlocking design of the convex shear key and the groove, a composite shear-resistant system is constructed, with the shear key and high-strength bolt working in tandem. The convex shear key extends into the locking hole to form a fixed connection, allowing horizontal shear force to be mainly transmitted through the bearing and shearing action of the shear key, while the high-strength bolt connection mainly bears the tensile force, thus optimizing the stress mode of the joint. This design effectively avoids the composite stress state caused by the bolts simultaneously bearing large shear and tensile forces in traditional beam-column joints, significantly improving the failure mode of the joint, transforming brittle shear failure into ductile bending failure, and improving the seismic performance and overall safety of the joint. Simultaneously, the composite hole-locking hole-groove design allows the high-strength bolts to be installed from the outside of the closed square steel pipe column, solving the technical problem of difficult installation of traditional steel structure joints on closed section columns, realizing true prefabricated construction, and greatly improving on-site installation efficiency.

[0012] Based on the above technical solution, the prefabricated beam-column joint of the steel structure building in the booster station of the present invention can be further improved as follows:

[0013] The inner convex shear key is a cylindrical or square steel component, the root of which is fully welded to the inner diaphragm of the column, and the length of its free end extending into the locking hole is not less than 1.5 times the wall thickness of the square steel tube column. An assembly gap of no more than 2mm is reserved between the end face of the inner convex shear key and the inner surface of the vertical plate.

[0014] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By limiting the shape, welding quality, and extension length of the convex shear key, sufficient stiffness and strength are ensured to effectively transmit horizontal shear force, while controlling the assembly gap ensures ease of installation. Full penetration welding ensures an equal-strength connection between the shear key and the internal diaphragm, preventing the connection from becoming a weak point in the structure, allowing the shear key to fully exert its shear bearing capacity, and improving the reliability and stability of force transmission at the joint.

[0015] Furthermore, the groove is a circular or square countersunk hole provided on the inner surface of the vertical plate. The depth of the groove matches the length of the inner convex shear key extending into the locking hole. The sidewall of the groove and the sidewall of the inner convex shear key are in clearance fit, and the fit clearance is controlled between 0.5mm and 1.5mm.

[0016] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the precise fit design of the groove and the inner convex shear key ensures the continuity and uniformity of shear force transmission and avoids stress concentration. The reasonable clearance fit not only ensures that the T-shaped connector can be smoothly assembled into place, but also ensures that the shear key and the sidewall of the groove can quickly contact and work together under horizontal loads, thereby improving the shear stiffness and deformation coordination of the joint.

[0017] Furthermore, the mounting hole on the vertical plate is a circular through hole, the center line of the mounting hole coincides with the center line of the locking hole, the diameter of the mounting hole is equal to the diameter of the locking hole and slightly larger than the diameter of the bolt shank of the high-strength bolt connection pair, the large hexagonal head of the high-strength bolt connection pair is located in the guide hole, and the bolt shank passes through the rectangular groove and enters the locking hole.

[0018] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the concentric arrangement and diameter matching design of the mounting holes and locking holes ensure the smooth installation and effective fastening of the high-strength bolt connection pairs. The three-level structure of the composite hole—the guide hole accommodating the bolt head, the groove guiding the movement of the bolt rod, and the locking hole achieving precise positioning—realizes convenient installation and reliable anchoring of high-strength bolts on closed-section columns, simplifies the construction process, and reduces the stringent requirements for construction accuracy.

[0019] Furthermore, a diaphragm bolt hole is provided on the inner diaphragm corresponding to the locking hole. The center line of the diaphragm bolt hole coincides with the center line of the locking hole. The end of the bolt shank of the high-strength bolt connection passes through the diaphragm bolt hole and is fastened by a nut. The inner convex shear key is arranged around the diaphragm bolt hole. The distance between the outer wall of the inner convex shear key and the edge of the diaphragm bolt hole is not less than 10mm.

[0020] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the setting of bolt holes on the transverse diaphragm of the column provides a continuous force transmission path for the high-strength bolts, realizing an effective connection between the T-shaped connector, the square steel tube column wall, and the transverse diaphragm of the column. The internally convex shear keys are arranged around the bolt holes at a reasonable distance, which not only ensures the operating space for bolt installation, but also brings the shear keys as close as possible to the bolt stress area, optimizing the force transmission path and improving the integrity and load-bearing efficiency of the joint area.

[0021] Furthermore, a locally thickened steel plate is welded to the outer wall surface of the square steel tube column surrounding the composite hole. The locally thickened steel plate covers the outer periphery of the inlet hole and the locking hole. The thickness of the locally thickened steel plate is 1.2 to 2.0 times the wall thickness of the square steel tube column. The outer surface of the locally thickened steel plate is in direct contact with the inner surface of the vertical plate to form a friction-type connection interface.

[0022] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the local thickening of the steel plate significantly improves the local bearing capacity and shear strength of the area around the composite opening, effectively disperses the concentrated load transmitted by the bolt tightening force and shear key, and avoids local buckling or tearing failure of the square steel tube column wall at the opening. At the same time, the thickened steel plate increases the friction coefficient of the friction-type connection interface, enhances the ability of the joint to resist horizontal shear force by friction, and provides favorable conditions for realizing the seismic design concept of "strong joint and weak member".

[0023] Furthermore, a vertical stiffening plate is welded between the vertical plate and the horizontal plate of the T-shaped connector. The vertical stiffening plate is a triangular or trapezoidal steel plate. One right-angled side of the vertical stiffening plate is welded to the vertical plate, and the other right-angled side is welded to the horizontal plate. The vertical stiffening plate is positioned to avoid the bolt shank axis of the high-strength bolt connection pair.

[0024] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the vertical stiffening plate significantly improves the stiffness of the connection area between the vertical and horizontal plates of the T-shaped connector, effectively reducing the rotational deformation of the horizontal plate relative to the vertical plate under load, thereby significantly reducing the prying force on the high-strength bolt connection pair. This design improves the stress state of the bolts, delays bolt fatigue damage, and improves the overall load-bearing capacity and ductile deformation capacity of the joint, making it particularly suitable for buildings in earthquake zones subjected to repeated loads.

[0025] Furthermore, horizontal stiffening plates are welded to both the upper and lower surfaces of the horizontal plate. The horizontal stiffening plates are strip steel plates and are arranged perpendicular to the longitudinal axis of the horizontal plate. The end of the horizontal stiffening plate near the vertical plate is welded and fixed to the vertical plate. The horizontal plate has multiple bolt holes for connecting the H-shaped steel beam, and the bolt holes are located between adjacent horizontal stiffening plates.

[0026] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the horizontal stiffening plate improves the local stability and bending stiffness of the horizontal plate, effectively disperses the concentrated load transmitted from the H-beam, and avoids local deformation of the horizontal plate at the bolt holes. The welding of the stiffening plate to the vertical plate enhances the integrity of the T-shaped connector, optimizes the load transfer path from the H-beam to the square steel column, and improves the overall performance and durability of the joint.

[0027] Furthermore, the ratio of the cross-sectional area of ​​the inner convex shear key to the cross-sectional area of ​​the locking hole is 0.6 to 0.8, the strength grade of the steel of the inner convex shear key is higher than the strength grade of the steel of the square steel pipe column, and the design value of the shear bearing capacity after the inner convex shear key and the groove are fitted together is greater than 1.2 times the design horizontal shear force of the node.

[0028] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By controlling the cross-sectional area ratio of the convex shear key to the locking hole, and by using high-strength steel to manufacture the shear key, sufficient shear safety reserve is ensured, enabling the shear key to maintain an elastic working state within the design load range and fully exert its shear resistance. The design value of the shear bearing capacity after the shear key and the groove are fitted together is greater than the technical requirement of the design horizontal shear force of the node, ensuring that the node has sufficient safety margin under extreme loads and meeting the reliability requirements of important building structures.

[0029] Furthermore, the T-shaped connector includes an upper T-shaped member and a lower T-shaped member, which are respectively disposed at the upper flange and lower flange of the H-shaped steel beam. The structures of the upper T-shaped member and the lower T-shaped member are arranged symmetrically about the neutral axis of the H-shaped steel beam. The grooves on the vertical plates of the upper T-shaped member and the lower T-shaped member respectively engage with the corresponding inwardly protruding shear keys to form a symmetrical shear force transmission system.

[0030] The beneficial effects of adopting the above-mentioned improved scheme are as follows: The symmetrically arranged T-shaped connectors form a complete couple resistance system, enabling both the upper and lower flanges of the H-beam to effectively participate in bending resistance, thereby improving the bending bearing capacity of the joint. The symmetrical shear force transfer system ensures that the horizontal shear force is evenly distributed in the upper and lower regions of the joint, avoiding stress concentration and improving the uniformity of stress distribution. The symmetrical structure simplifies the fabrication and on-site installation of components, improving construction quality and efficiency, while also giving the joint good bidirectional load-bearing performance, adapting to complex load conditions.

[0031] Compared with existing technologies, the beneficial effects of the prefabricated beam-column joint for steel structure buildings in substations provided by this invention are as follows: This invention addresses the shortcomings of existing technologies by providing a prefabricated beam-column joint for steel structure buildings in substations. Through the synergistic work of embedded shear keys and composite holes, it optimizes the stress mode of the joint and significantly improves construction convenience. Firstly, this invention welds an inwardly protruding shear key onto the transverse diaphragm inside the column, allowing it to extend into the locking hole in the square steel tube column wall to form a fixed connection. Simultaneously, a matching groove is provided on the inner side of the vertical plate of the T-shaped connector, constructing a shear key-high-strength bolt synergistic shear-resistant system. This structure allows horizontal shear force to be mainly transmitted through the bearing and shearing action of the shear key, while the high-strength bolts mainly bear the tensile force, effectively avoiding brittle failure caused by the combined shear-tensile stress on the bolts in traditional joints, and significantly improving the ductility and seismic safety of the joint. Secondly, the composite opening utilizes a special design with guide holes, locking holes, and connecting grooves, allowing high-strength bolts to be installed from the outside of the closed square steel tube column. This completely solves the operability problem of bolted connections in closed-section columns, achieving true prefabricated construction, significantly improving on-site installation efficiency and reducing dependence on construction conditions. Thirdly, the locally thickened steel plates enhance the local bearing capacity and friction coefficient of the opening area, providing favorable conditions for seismic design of strong nodes and weak components. The configuration of vertical and horizontal stiffening plates effectively reduces prying forces, improving the overall stiffness and load-bearing efficiency of the node. Furthermore, the symmetrically arranged T-shaped connectors form a complete couple resistance system, giving the node excellent bidirectional load-bearing performance and uniform load distribution, adapting to complex load conditions. Attached Figure Description

[0032] Figure 1 This is a three-dimensional diagram of the prefabricated beam-column joint of a steel structure building in a substation according to the present invention.

[0033] Figure 2 This is an elevation view of the prefabricated beam-column joint of a steel structure building in a substation according to the present invention.

[0034] Figure 3 This is a top view of a prefabricated beam-column joint in a steel structure building within a substation according to the present invention.

[0035] Figure 4This is a schematic diagram of the composite hole on the steel pipe column of the present invention;

[0036] Figure 5 This is a structural diagram of the T-shaped connector of the present invention;

[0037] Figure 6 This is an example diagram of the convex shear key of the present invention.

[0038] The attached diagram lists the components represented by each number as follows:

[0039] 1. Square steel tube column; 2. Column internal diaphragm; 21. Internally projecting shear key; 3. Lower T-shaped member; 4. H-shaped steel beam; 5. Upper T-shaped member; 6. High-strength bolt connection pair. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0041] like Figures 1-6 The diagram shown is an example of a prefabricated beam-column joint for a steel structure building within a substation, provided by the present invention, including:

[0042] The square steel tube column 1 has a pre-fabricated composite hole on its side wall. The composite hole includes an upper inlet hole, a lower locking hole, and a rectangular groove connecting the two holes. The diameter of the inlet hole is larger than the diameter of the locking hole.

[0043] The column diaphragm 2 is set inside the square steel tube column 1 and welded to the inner wall of the square steel tube column 1. The inner convex shear key 21 is welded to the side surface of the column diaphragm 2 facing the composite hole. The position of the inner convex shear key 21 corresponds to the locking hole and extends into the locking hole to form a fixed fit.

[0044] The T-shaped connector includes a vertical plate and a horizontal plate. The vertical plate and the horizontal plate are welded vertically to form an integral T-shaped component. The outer surface of the vertical plate is attached to the outer wall of the square steel column 1. The inner surface of the vertical plate is provided with a groove that matches the inner convex shear key 21. The end of the horizontal plate away from the vertical plate is connected to the H-shaped steel beam 4 by bolts.

[0045] The high-strength bolt connection pair 6 has its bolt shank passing through the mounting holes, locking holes and corresponding holes on the vertical plate and the transverse diaphragm 2 inside the column in sequence, to fasten the T-shaped connector to the square steel pipe column 1. The inner convex shear key 21 fits into the groove to form a shear force transmission structure, which bears the horizontal shear force at the node.

[0046] Specific implementation steps:

[0047] Step 1: First, select steel plates that meet the strength requirements according to the design drawings, and use CNC cutting equipment to cut and fabricate the four wall panels of the square steel tube column. Mark the location of the composite hole on one of the wall panels, and use a CNC drilling machine or laser cutting equipment to process the guide hole, locking hole, and rectangular groove connecting the two. The diameter of the guide hole is larger than the diameter of the locking hole, and the width of the groove is equal to the diameter of the locking hole. Then, weld a locally thickened steel plate to the outer perimeter of the composite hole. The locally thickened steel plate is connected to the square steel tube column wall panel by full penetration welding or fillet weld, and the surface is ground smooth after welding. Next, cut the internal diaphragm into shape, open bolt holes for the diaphragm at the corresponding locking hole positions, and weld an internally protruding shear key on the side of the diaphragm facing the composite hole. The internally protruding shear key is made of the same material as the internal diaphragm or a higher strength grade steel, and the welding method is full penetration welding. Post-weld flaw detection inspection ensures the weld quality. Finally, the inner diaphragm plate with the welded inner shear key is placed into the predetermined position inside the square steel tube column. The inner shear key is adjusted to align and extend into the locking hole. The inner diaphragm plate is then welded and fixed to the inner wall of the square steel tube column using automatic welding equipment, thus completing the factory prefabrication of the square steel tube column assembly.

[0048] Step Two: Select steel plates of the appropriate strength grade according to the design requirements, and cut them to fabricate vertical plates, horizontal plates, vertical stiffening plates, and horizontal stiffening plates. Use a CNC drilling machine to machine mounting holes on the vertical plates, ensuring the hole diameter matches the locking hole diameter. Mill or drill grooves on the inner surface of the vertical plates to accommodate the inner shear key, with the groove depth matching the length of the inner shear key extending into the locking hole. Leave appropriate assembly clearance between the groove sidewall and the inner shear key sidewall. Mark and drill the bolt hole positions for the H-beam connection on the horizontal plates, and mark the horizontal stiffening plate positions on the upper and lower surfaces of the horizontal plates. Assemble the vertical and horizontal plates perpendicularly, and weld them into a T-shaped integral component using automatic or semi-automatic welding, ensuring the weld quality grade is not lower than Grade II. Then, weld the vertical stiffening plate between the vertical and horizontal plates, and weld the horizontal stiffening plates to the upper and lower surfaces of the horizontal plates. The vertical stiffening plates should be positioned away from the mounting hole axis, and the horizontal stiffening plates should be welded to the vertical plates at the end closest to them. The T-shaped connectors are inspected for dimensions and appearance. After passing the inspection, the surface is derusted and coated with anti-corrosion paint.

[0049] Step 3: Select suitable H-beams according to the design drawings, or weld H-beams from steel plates. Drill holes in the end flanges and webs of the steel beams, aligning the hole positions with the bolt holes on the horizontal plate of the T-shaped connectors. Perform dimensional inspection, weld flaw detection, and anti-corrosion coating on the H-beams.

[0050] Step 4: Hoist the prefabricated square steel pipe column into position and ensure its verticality is corrected and securely fixed. Transport the lower T-shaped component to the installation location, aligning the vertical plate with the corresponding composite hole area on the outer wall of the square steel pipe column. Adjust the position so that the groove on the inner side of the vertical plate aligns with the inner convex shear key. Push the lower T-shaped component horizontally to embed the inner convex shear key into the groove, achieving the fitting and positioning of the shear key and the groove. Use temporary fixing measures to secure the lower T-shaped component to the square steel pipe column to ensure that its position does not shift during subsequent installation.

[0051] Step 5: Take the high-strength bolt connection pair. Place the large hexagonal head of the bolt into the guide hole. Let the bolt shank slide down the guide hole to the groove position. Push the bolt shank horizontally to make it slide along the groove to the locking hole position. At this time, the bolt shank passes through the mounting hole on the vertical plate, the locking hole on the square steel tube column wall, and the bolt hole on the transverse diaphragm plate inside the column in sequence. Install the washer and nut on the other side of the transverse diaphragm plate inside the column. Use a torque wrench or torque shear wrench to initially tighten the high-strength bolt. The initial tightening torque is about 50% of the final tightening torque, so that all parts of the connection pair fit tightly.

[0052] Step Six: Hoist the prefabricated H-beam into place, placing the end of the beam on the horizontal plate of the lower T-shaped piece. Adjust the position and elevation of the beam, aligning the bolt holes on the beam with the bolt holes on the horizontal plate. Temporarily fix the beam with ordinary or high-strength bolts to ensure its stability.

[0053] Step 7: Following the same installation method as the lower T-shaped piece, install the upper T-shaped piece at the corresponding position on the square steel pipe column, so that the groove on the inner side of the vertical plate of the upper T-shaped piece fits into the corresponding inner convex shear key, the vertical plate is attached to the outer wall of the square steel pipe column, and the lower surface of the horizontal plate is attached to the upper flange of the H-shaped steel beam. After aligning the bolt holes, insert the connecting bolts for temporary fixation.

[0054] Step 8: After all components at the node have been adjusted and temporarily secured, use the torque method or torque-shear method to final tighten the high-strength bolt connections installed in Step 5 to achieve the designed preload value. After final tightening, mark the bolts with different colored paint or markers to prevent omissions and re-tightening. Finally, tighten the connecting bolts between the T-shaped connectors and the H-beams to ensure reliable fastening at all connection points.

[0055] Step Nine: Conduct quality inspection on the installed beam-column joints, including random checks of bolt preload, inspection of joint dimensional deviations, and visual inspection of welds. After passing the inspection, repair any damaged anti-corrosion coatings during on-site installation to ensure that the anti-corrosion performance of the joint area meets design requirements.

[0056] In the above technical solution, the inner convex shear key 21 is a cylindrical or square steel component. Its root is fully welded to the transverse diaphragm 2 inside the column. The length of its free end extending into the locking hole is not less than 1.5 times the wall thickness of the square steel tube column 1. An assembly gap of no more than 2mm is reserved between the end face of the inner convex shear key 21 and the inner surface of the vertical plate.

[0057] Furthermore, in the above technical solution, the groove is a circular or square countersunk hole set on the inner surface of the vertical plate. The depth of the groove matches the length of the inner convex shear key 21 extending into the locking hole. The sidewall of the groove and the sidewall of the inner convex shear key 21 are in clearance fit, and the fit clearance is controlled between 0.5mm and 1.5mm.

[0058] Furthermore, in the above technical solution, the mounting hole on the vertical plate is a circular through hole, the center line of the mounting hole coincides with the center line of the locking hole, the diameter of the mounting hole is equal to the diameter of the locking hole and slightly larger than the diameter of the bolt rod of the high-strength bolt connection pair 6, the large hexagonal head of the high-strength bolt connection pair 6 is located in the guide hole, and the bolt rod passes through the rectangular groove into the locking hole.

[0059] Furthermore, in the above technical solution, a diaphragm bolt hole is provided on the inner diaphragm 2 at the position corresponding to the locking hole. The center line of the diaphragm bolt hole coincides with the center line of the locking hole. The end of the bolt rod of the high-strength bolt connection pair 6 passes through the diaphragm bolt hole and is fastened by a nut. The inner convex shear key 21 is arranged around the diaphragm bolt hole. The distance between the outer wall of the inner convex shear key 21 and the edge of the diaphragm bolt hole is not less than 10mm.

[0060] Furthermore, in the above technical solution, a locally thickened steel plate is welded to the outer wall surface of the square steel column 1 around the composite hole. The locally thickened steel plate covers the outer periphery of the inlet hole and the locking hole. The thickness of the locally thickened steel plate is 1.2 to 2.0 times the wall thickness of the square steel column 1. The outer surface of the locally thickened steel plate is in direct contact with the inner surface of the vertical plate to form a friction-type connection interface.

[0061] Furthermore, in the above technical solution, a vertical stiffening plate is welded between the vertical plate and the horizontal plate of the T-shaped connector. The vertical stiffening plate is a triangular or trapezoidal steel plate. One right-angled side of the vertical stiffening plate is welded to the vertical plate, and the other right-angled side is welded to the horizontal plate. The arrangement of the vertical stiffening plate avoids the bolt rod axis of the high-strength bolt connection pair 6.

[0062] Furthermore, in the above technical solution, horizontal stiffening plates are welded to both the upper and lower surfaces of the horizontal plate. The horizontal stiffening plates are strip steel plates and are arranged perpendicular to the longitudinal axis of the horizontal plate. The end of the horizontal stiffening plate near the vertical plate is welded and fixed to the vertical plate. Multiple bolt holes for connecting the H-beam 4 are opened on the horizontal plate, and the bolt holes are located between adjacent horizontal stiffening plates.

[0063] Furthermore, in the above technical solution, the ratio of the cross-sectional area of ​​the inner convex shear key 21 to the cross-sectional area of ​​the locking hole is 0.6 to 0.8, the strength grade of the steel of the inner convex shear key 21 is higher than the strength grade of the steel of the square steel pipe column 1, and the design value of the shear bearing capacity after the inner convex shear key 21 and the groove are fitted together is greater than 1.2 times the design horizontal shear force of the node.

[0064] Furthermore, in the above technical solution, the T-shaped connector includes an upper T-shaped member 5 and a lower T-shaped member 3, which are respectively disposed at the upper flange and lower flange of the H-shaped steel beam 4. The structures of the upper T-shaped member 5 and the lower T-shaped member 3 are arranged symmetrically about the neutral axis of the H-shaped steel beam 4. The grooves on the vertical plates of the upper T-shaped member 5 and the lower T-shaped member 3 are respectively engaged with the corresponding inwardly protruding shear keys 21 to form a symmetrical shear force transmission system.

[0065] The following provides a specific embodiment 1 of the present invention, and the specific implementation of each step in this embodiment 1 is described in detail below.

[0066] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 1 This is a three-dimensional diagram of the prefabricated beam-column joint of a steel structure building in a substation according to the present invention. Figure 2 This is an elevation view of the prefabricated beam-column joint of a steel structure building in a substation according to the present invention. Figure 3 This is a top view of a prefabricated beam-column joint in a substation steel structure according to the present invention. 1. Square steel pipe column, 2. Inner column diaphragm, 3. Lower T-shaped member, 4. H-shaped steel beam, 5. Upper T-shaped member, and 6. High-strength bolt connection pair. Figure 4 This is a schematic diagram of the composite hole on the square steel pipe column of the present invention; Figure 5 This is a structural diagram of the T-shaped parts used in the lower T-shaped part 3 and the upper T-shaped part 5 of the present invention.

[0067] This invention proposes a prefabricated beam-column joint for steel structure buildings within a substation, comprising: square steel tubular columns, internal diaphragms, lower T-shaped members, H-shaped steel beams, upper T-shaped members, and high-strength bolt connections. All welds in this structure are completed in the factory prefabrication stage, and on-site assembly is achieved solely through high-strength bolt connections, eliminating the need for welding. This not only improves construction efficiency and quality control but also facilitates subsequent disassembly and maintenance, while eliminating quality fluctuations, safety hazards, and environmental pollution associated with on-site welding.

[0068] The standardized installation method for T-shaped fittings and snap-fit ​​bolt assembly joints of square steel pipe columns and H-shaped steel beams includes the following steps:

[0069] (1) Factory prefabricated column placement: The prefabricated square steel pipe column components that have been welded in the factory will be transported to the construction site and hoisted, corrected and fixed.

[0070] (2) Installation and fixing of the lower T-shaped part: Pass the high-strength bolt through the vertical steel plate of the lower T-shaped part in advance and turn the nut a few turns to prevent the high-strength bolt from slipping off; then hold the lower T-shaped part and pass the bolt through the guide hole at the top of the composite hole in the column wall from the outside of the square steel pipe column. After the bolt head is completely inside the column, move the bolt downward so that it slides into the locking hole at the bottom along the rectangular channel and is locked. Then the external nut can be tightened to complete the connection between the lower T-shaped part and the square steel pipe column.

[0071] (3) H-beam hoisting and preliminary positioning: Hoist the factory-prefabricated H-beams to the design elevation position, so that their lower flanges are located above the horizontal plate of the lower T-shaped piece. Insert high-strength bolts into the holes and tighten them to achieve the preliminary positioning and connection of the H-beams.

[0072] (4) Installation of the upper T-shaped part: Pass the high-strength bolt through the vertical steel plate of the upper T-shaped part in advance and turn the nut a few turns to prevent the high-strength bolt from slipping off; then hold the upper T-shaped part and pass the bolt through the guide hole at the top of the composite hole in the column wall from the outside of the square steel pipe column. After the bolt head is completely inside the column, move the bolt downward so that it slides into the locking hole at the bottom along the rectangular channel and is locked. Then the external nut can be tightened to complete the connection between the upper T-shaped part and the square steel pipe column.

[0073] (5) Repeat step (4) to complete the connection between the upper T-shaped piece and the steel beam;

[0074] (6) Finally, tighten all the nuts of the high-strength bolt connections to the designed preload.

[0075] It should be noted that this node is controllable in design. By adjusting the length of the chute, the stiffness coefficient of the beam-column joint can be controlled, thereby achieving a certain design performance more precisely.

[0076] To better understand and implement this invention, a specific application scenario is provided below as Example 2: A substation's main control building is a two-story steel frame structure, 12 meters high, with a seismic fortification intensity of 8 degrees and a design basic seismic acceleration of 0.20g. The main structure adopts a square steel tube column frame system, with square steel tube columns having a cross-section of □400×400×16 mm and Q355B steel material. Based on the electrical equipment layout and building functional requirements, a main transformer foundation needs to be added on the second floor at the intersection of axis 3-4 and axis BC. This necessitates that the connection node between the originally designed H400×200×8×13 steel beam and the □400×400×16 square steel tube column at this location possess higher load-bearing capacity and better seismic performance. During implementation, construction personnel fabricated and installed the beam-column prefabricated node according to the method of this invention.

[0077] First, the square steel tube column assembly is prefabricated in the factory. Four wall panels for the square steel tube column are made from 16mm thick Q355B steel plates using CNC flame cutting, with a panel width of 400mm. The locations of the composite holes are marked on the column wall panels at the intersection of axis 3 and axis B. The upper guide hole and the lower locking hole are machined using a CNC drilling machine. The guide hole has a diameter of 30mm, and the locking hole has a diameter of 22mm, with a center distance of 50mm. A rectangular groove with a width of 22mm and a length of 50mm is milled between the two holes to form the composite hole. A locally thickened steel plate, made of 20mm thick Q355B steel plate with dimensions of 200mm × 150mm, is welded to the outer periphery of the composite hole. This locally thickened steel plate covers the outer periphery of the guide hole and locking hole. The locally thickened steel plate is connected to the square steel tube column wall panels using fillet welds with a weld leg size of 10mm. After welding, the surface is ground smooth and ultrasonic testing is performed. Subsequently, 20 mm thick Q355B steel plates were cut to fabricate the internal diaphragm of the column. The diaphragm has an external dimension of 368 mm × 368 mm. Bolt holes with a diameter of 24 mm were drilled at the corresponding locking hole positions. An internal convex shear key was welded to the side of the diaphragm bolt hole facing the composite hole. The internal convex shear key is made of round steel with a diameter of 30 mm and a length of 40 mm, and the material is Q420B. The root of the internal convex shear key is fully penetrated welded to the internal diaphragm of the column. After welding, magnetic particle inspection was performed to ensure the quality of the weld. The free end of the internal convex shear key extends 24 mm into the locking hole. The internal transverse diaphragm with welded internal shear keys is placed inside the square steel tube column at a distance of 1.2 meters from the top of the column. The internal shear keys are adjusted to align and extend into the locking holes. The internal transverse diaphragm is welded to the inner wall of the square steel tube column using CO2 gas shielded welding. The weld quality grade is Grade 1, thus completing the factory prefabrication of the square steel tube column assembly. After prefabrication, sandblasting and rust removal and epoxy zinc-rich primer coating are performed.

[0078] Next, the T-shaped connectors are prefabricated in the factory. Vertical plates are made from 20mm thick Q355B steel plates, 400mm high and 200mm wide. 22mm diameter mounting holes are machined using a CNC drilling machine, with the center of each hole 100mm from the bottom edge of the vertical plate. A 32mm diameter, 24mm deep circular groove is machined on the inner surface of the vertical plate using CNC milling, with the center of the groove coinciding with the center of the mounting hole. Horizontal plates are made from 16mm thick Q355B steel plates, 300mm long and 200mm wide. The positions of the horizontal stiffening plates are marked on the upper and lower surfaces of the horizontal plates. Bolt holes, 22mm in diameter and 100mm apart, are drilled on the horizontal plates for connection to the H-beams. The vertical and horizontal plates are then vertically assembled and welded into a T-shaped integral component using CO2 gas shielded welding, with a weld quality grade of Class II. Vertical stiffening plates are welded between the vertical and horizontal plates. These stiffening plates are made of 12mm thick Q355B steel, and are right-angled triangles with legs of 150mm and 100mm respectively. Their placement avoids the axis of the mounting holes and is 80mm from the center line of the mounting holes. Horizontal stiffening plates are welded to the upper and lower surfaces of the horizontal plates. These horizontal stiffening plates are made of 10mm thick Q355B steel, 80mm wide and 180mm long. They are welded to the vertical plates at the ends closest to them, with a net distance of 100mm between each horizontal stiffening plate, ensuring that bolt holes are located between adjacent horizontal stiffening plates. The T-shaped connectors are dimensionally inspected. The flatness deviation of the vertical plates is controlled within 1mm, and the coaxiality deviation between the mounting holes and grooves is controlled within 0.5mm. After passing inspection, surface rust removal and epoxy zinc-rich primer coating are applied.

[0079] Meanwhile, H-beams are prefabricated in the factory, using H400×200×8×13 hot-rolled H-beams made of Q355B steel. Holes are drilled on the end flanges and webs of the steel beams, with the hole positions corresponding to the bolt holes on the horizontal plate of the T-shaped connectors. The hole diameter is 22 mm. After sandblasting to remove rust and applying primer, the beams are transported to the site.

[0080] During the on-site installation stage, first hoist the prefabricated square steel pipe column in place, use a theodolite to correct the verticality, with the deviation controlled within H / 1000 and not exceeding 10 mm, and temporarily fix it firmly with guy ropes. Transport the lower T-shaped part to the installation position, make the vertical plate fit the outer wall of the square steel pipe column corresponding to the composite hole area on the 3-axis, adjust the position so that the groove on the inner side of the vertical plate aligns with the inner convex shear key, and horizontally push the lower T-shaped part to embed the inner convex shear key into the groove to achieve the fitting and positioning of the shear key and the groove. At this time, the inner surface of the vertical plate is closely fitted with the outer surface of the locally thickened steel plate, and use temporary angle steel clamps to fix the lower T-shaped part on the square steel pipe column. Take the 10.9 grade M20 high-strength bolt connection pair, place the large hexagon head of the bolt in the lead-in hole, and let the bolt rod slide down along the lead-in hole to the chute position. Horizontally push the bolt rod to make it slide along the chute to the locking hole position. At this time, the bolt rod passes through the installation hole on the vertical plate, the locking hole on the wall of the square steel pipe column, and the diaphragm bolt hole on the diaphragm inside the column in sequence. Install washers and nuts on the other side of the diaphragm inside the column, and use a torque wrench for initial tightening, with the initial tightening torque being 50% of the final tightening torque. Install the upper T-shaped part in the same way. The upper T-shaped part is 400 mm above the lower T-shaped part and corresponds to another set of composite holes and inner convex shear keys at the upper part of the square steel pipe column.

[0081] Subsequently, hoist the prefabricated H400×200×8×13 steel beam in place, adjust the position of the steel beam so that the bottom surface of the lower flange fits the upper surface of the horizontal plate of the lower T-shaped part, and the top surface of the upper flange fits the lower surface of the horizontal plate of the upper T-shaped part. After aligning the bolt holes, insert 10.9 grade M20 high-strength bolts for temporary fixation. After the position and elevation of the steel beam are adjusted, use the torque method to finally tighten the high-strength bolts connecting the square steel pipe column and the T-shaped part, with the final tightening torque being 450 N·m. Use the twist-off method to finally tighten the high-strength bolts connecting the T-shaped part and the steel beam, and it is qualified if the plum blossom head at the tail of the bolt is twisted off. After the final tightening is completed, use red paint to mark the bolts to prevent missed tightening.

[0082] After the node installation is completed, conduct quality inspection. Use the torque method to randomly check the pre-tension of 10% of the high-strength bolts, and it is qualified if the measured pre-tension value is between 95% and 105% of the design value; use a 0.3 mm feeler gauge to check the fitting degree between the vertical plate and the locally thickened steel plate, and it is qualified if the insertion depth does not exceed 20 mm; use an ultrasonic flaw detector to randomly check 20% of the welds, and it is qualified if no cracks, lack of fusion and other defects are found. After passing the inspection, use epoxy zinc-rich primer to touch up the damaged anti-corrosion coating during the on-site installation process, with the coating thickness not less than 75 microns, ensuring that the anti-corrosion performance of the node area meets the requirements of the design service life.

[0083] This embodiment achieves efficient prefabricated connection between square steel tube columns and H-beams by adopting an embedded shear key-composite hole synergistic shear resistance structure. The shear bearing capacity of the joint is significantly improved compared with traditional joints, and the failure mode changes from brittle shear to ductile bending. This meets the seismic fortification requirements of the main control building of the substation in a high-intensity earthquake zone. At the same time, it realizes on-site welding-free all-bolt assembly construction, shortening the construction period by about 40% compared with traditional welded joints, demonstrating good technical and economic benefits.

[0084] Specifically, the principle of this invention is as follows: Based on the force flow optimization theory in structural mechanics and the convenience principle of prefabricated construction, this invention fundamentally improves the stress distribution mode of nodes through structural innovation. Regarding the force transmission mechanism, this invention breaks through the traditional single-mode reliance on bolts for shear resistance, introducing an embedded shear key as the primary horizontal shear force transmission element. The convex shear key is fully penetrated welded to the internal diaphragm of the column, its free end extending into the locking hole of the square steel tube column wall and fitting into the groove on the inner side of the vertical plate of the T-shaped connector, forming a rigid shear force transmission path. When a horizontal load is applied to the node, the shear force is transmitted through the vertical plate of the T-shaped connector to the side wall of the groove, then from the side wall to the convex shear key, and finally transmitted to the entire square steel tube column through the connection between the shear key and the internal diaphragm. This force transmission path allows the shear key to bear the majority of the horizontal shear force, while the high-strength bolt connection mainly provides vertical tension to ensure the integrity of the node, thus achieving an optimized force distribution of "shear resistance by the shear key and tension resistance by the bolts." In terms of assembly process, this utility model utilizes a three-stage structure of composite holes to achieve external bolt installation: the guide hole accommodates the large hexagonal head of the bolt and provides initial positioning space; the rectangular groove allows the bolt shank to slide and adjust horizontally; and the locking hole achieves final precise positioning and tightening of the bolt. This design utilizes the diameter difference between the bolt head and shank, and through the guiding effect of the groove, the bolt can smoothly pass through from outside the column and reach the working position, eliminating the need for large hand holes in the column wall or segmented assembly. In terms of structural details, locally thickened steel plates enhance the frictional shear resistance and local stability of the joint by increasing the stiffness and friction coefficient of the perimeter area; the stiffening plate reduces the prying effect by increasing the stiffness of the T-shaped connector, optimizing the stress state of the bolt. The symmetrical arrangement of the upper and lower parts of the structure forms a complete couple resistance system for the joint, ensuring the effective transmission of bending moment at the beam end and the uniform distribution of force flow in the joint area.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A prefabricated beam-column joint for a steel structure building within a substation, characterized in that, include: The square steel tube column has pre-fabricated composite holes on its sidewalls. The composite holes include an upper inlet hole, a lower locking hole, and a rectangular groove connecting the two holes. The diameter of the inlet hole is larger than the diameter of the locking hole. An internal diaphragm is provided inside the square steel tube column and welded to the inner wall of the square steel tube column. An internal convex shear key is welded to the side surface of the internal diaphragm facing the composite hole. The position of the internal convex shear key corresponds to the locking hole and extends into the locking hole to form a fixed fit. The T-shaped connector includes a vertical plate and a horizontal plate. The vertical plate and the horizontal plate are welded perpendicularly to form an integral T-shaped component. The outer surface of the vertical plate is attached to the outer wall of the square steel tube column. The inner surface of the vertical plate is provided with a groove that matches the inner convex shear key. The end of the horizontal plate away from the vertical plate is connected to the H-shaped steel beam by bolts. The high-strength bolt connection pair has its bolt shank passing sequentially through the mounting hole on the vertical plate, the locking hole, and the corresponding hole on the transverse diaphragm inside the column, fastening the T-shaped connector to the square steel pipe column. The inner convex shear key and the groove fit together to form a shear force transmission structure, bearing the horizontal shear force at the node.

2. The prefabricated beam-column joint for a steel structure building within a substation according to claim 1, characterized in that, The inner convex shear key is a cylindrical or square steel component, with its root fully welded to the inner diaphragm of the column. The length of its free end extending into the locking hole is not less than 1.5 times the wall thickness of the square steel tube column. An assembly gap of no more than 2mm is reserved between the end face of the inner convex shear key and the inner surface of the vertical plate.

3. The prefabricated beam-column joint for a steel structure building within a substation according to claim 2, characterized in that, The groove is a circular or square countersunk hole set on the inner surface of the vertical plate. The depth of the groove matches the length of the inner convex shear key extending into the locking hole. The sidewall of the groove and the sidewall of the inner convex shear key are in clearance fit, and the clearance is controlled between 0.5mm and 1.5mm.

4. The prefabricated beam-column joint for a steel structure building within a substation according to claim 3, characterized in that, The mounting hole on the vertical plate is a circular through hole. The center line of the mounting hole coincides with the center line of the locking hole. The diameter of the mounting hole is equal to the diameter of the locking hole and slightly larger than the diameter of the bolt shank of the high-strength bolt connection pair. The large hexagonal head of the high-strength bolt connection pair is located in the guide hole. The bolt shank passes through the rectangular groove and enters the locking hole.

5. The prefabricated beam-column joint for a steel structure building within a substation according to claim 4, characterized in that, The inner diaphragm of the column has bolt holes corresponding to the locking holes. The center line of the bolt holes coincides with the center line of the locking holes. The end of the bolt shank of the high-strength bolt connection passes through the bolt holes and is fastened with a nut. The inner convex shear key is arranged around the bolt holes. The distance between the outer wall of the inner convex shear key and the edge of the bolt holes is not less than 10mm.

6. The prefabricated beam-column joint for a steel structure building within a substation according to claim 5, characterized in that, A locally thickened steel plate is welded to the outer wall surface of the square steel tube column surrounding the composite hole. The locally thickened steel plate covers the outer periphery of the inlet hole and the locking hole. The thickness of the locally thickened steel plate is 1.2 to 2.0 times the wall thickness of the square steel tube column. The outer surface of the locally thickened steel plate is in direct contact with the inner surface of the vertical plate to form a friction-type connection interface.

7. The prefabricated beam-column joint for a steel structure building within a substation according to claim 6, characterized in that, A vertical stiffening plate is welded between the vertical plate and the horizontal plate of the T-shaped connector. The vertical stiffening plate is a triangular or trapezoidal steel plate. One right-angle side of the vertical stiffening plate is welded to the vertical plate, and the other right-angle side is welded to the horizontal plate. The vertical stiffening plate is positioned to avoid the bolt shank axis of the high-strength bolt connection pair.

8. The prefabricated beam-column joint for a steel structure building within a substation according to claim 7, characterized in that, Horizontal stiffening plates are welded to both the upper and lower surfaces of the horizontal plate. The horizontal stiffening plates are strip steel plates and are arranged perpendicular to the longitudinal axis of the horizontal plate. The end of the horizontal stiffening plate near the vertical plate is welded and fixed to the vertical plate. The horizontal plate has multiple bolt holes for connecting the H-shaped steel beam, and the bolt holes are located between adjacent horizontal stiffening plates.

9. The prefabricated beam-column joint for a steel structure building within a substation according to claim 8, characterized in that, The ratio of the cross-sectional area of ​​the inner convex shear key to the cross-sectional area of ​​the locking hole is 0.6 to 0.

8. The steel strength grade of the inner convex shear key is higher than that of the square steel pipe column. The design value of the shear bearing capacity after the inner convex shear key and the groove are fitted together is greater than 1.2 times the design horizontal shear force of the node.

10. A prefabricated beam-column joint for a steel structure building within a substation according to claim 9, characterized in that, The T-shaped connector includes an upper T-shaped member and a lower T-shaped member, which are respectively disposed at the upper flange and lower flange of the H-shaped steel beam. The structures of the upper T-shaped member and the lower T-shaped member are arranged symmetrically about the neutral axis of the H-shaped steel beam. The grooves on the vertical plates of the upper T-shaped member and the lower T-shaped member respectively engage with the corresponding inwardly protruding shear keys to form a symmetrical shear force transmission system.

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