A substation frame beam-column connection structure and design method thereof

Abstract

The invention discloses a substation frame beam-column connection structure and a design method thereof, comprising a steel tube herringbone column, an inlet and outlet line beam and a busbar beam, wherein the inlet and outlet line beam and the busbar beam are fixedly connected to the steel tube herringbone column; the inlet and outlet line beam and the busbar beam are both triangular cross-section lattice beams; an annular node plate of a steel tube herringbone column and a cantilevered corbel top plate are arranged at the connection node of the steel tube herringbone column, a stiffening plate is arranged below the annular node plate of the steel tube herringbone column, a column top plate is arranged at the top of the steel tube herringbone column, a stiffening plate is arranged below the column top plate, the inlet and outlet line beam is arranged above the busbar beam, the upper chord rod and the lower chord rod of the busbar beam are respectively connected to the steel tube herringbone column; the upper chord rod and the lower chord rod of the inlet and outlet line beam are respectively connected to the steel tube herringbone column. When the frame beam and the steel tube herringbone column are fixedly connected, the column section is correspondingly reduced; the force is evenly applied at the mid-span and the support of the beam; the beam section is reduced, the beam and column can be coordinated to bear force, and the integrity of the frame structure is improved; the column top plate size and the number of stiffening plates are greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of substation frame design, and in particular relates to a substation frame beam-column connection structure and a design method thereof. Background Art

[0002] In some new 750kV substation projects, the 750kV distribution device area adopts the HGIS layout scheme. The 750kV joint frame consists of incoming and outgoing line beams, busbar beams and steel pipe herringbone columns. The busbar beams are arranged vertically with the incoming and outgoing line beams. The span of the incoming and outgoing line beams is 41.0m, and the height of the hanging point is 42.5m. The span of the busbar beam is 42.5m, and the height of the hanging point is 31.0m. The joint frame columns adopt steel pipe herringbone columns, and the joint frame beams adopt triangular cross-section lattice beams, and the beams and columns are hinged. The force coordination and integrity of the entire structure are poor, and the material utilization rate is low. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides a substation frame beam-column connection structure and a design method thereof. Aiming at the connection node type of large-span triangular lattice beams and steel pipe herringbone columns in the combined frame of the substation, a fixed connection type is adopted for the beams and columns from the aspects of structural force and construction requirements, and a structural type of fixed connection between large-span triangular cross-section lattice beams and steel pipe herringbone columns is adopted, so as to fully utilize the mechanical properties of steel with high tensile, compressive and bending strength and good toughness, and reduce the structural cost.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a substation frame beam-column connection structure, including incoming and outgoing line beams, busbar beams and steel tube herringbone columns, the incoming and outgoing line beams and the busbar beams are fixedly connected to the steel tube herringbone columns; the incoming and outgoing line beams and the busbar beams are both triangular cross-section lattice beams; annular node plates of steel tube herringbone columns and cantilevered corbel top plates are arranged at the connection nodes of the steel tube herringbone columns, the cantilevered corbel top plates include cantilevered corbel top plates connected to the incoming and outgoing line beams and cantilevered corbel top plates connected to the busbar beams, a stiffening plate is arranged below the annular node plates of the steel tube herringbone columns, a column top plate is arranged at the top of the steel tube herringbone columns, a stiffening plate is arranged below the column top plate, the incoming and outgoing line beams are arranged above the busbar beams, the upper chord rods of the busbar beams and the lower chord rods of the busbar beams are respectively connected to the steel tube herringbone columns; the upper chord rods of the incoming and outgoing line beams and the lower chord rods of the incoming and outgoing line beams are respectively connected to the steel tube herringbone columns; the upper chord rods of the incoming and outgoing line beams are connected to the column top plates through rod end connecting plates.

[0005] Cross steel tube web members are arranged within the height range of the busbar beam in the plane of the steel tube herringbone column.

[0006] The stiffening plate passes through the steel pipe of the steel pipe herringbone column.

[0007] The vertical diagonal web members of the busbar beam at the beam end of the busbar beam are connected to the stiffening plate below the annular node plate of the steel tube herringbone column. The horizontal cross diagonal web members of the busbar beam at the beam end of the busbar beam are connected to the rod end connection plate of the lower chord of the busbar beam. The rod end connection plate of the lower chord of the busbar beam is then connected to the cantilevered corbel top plate on the steel tube herringbone column connected to the busbar beam.

[0008] The vertical diagonal web members of the incoming and outgoing line beams located at the ends of the incoming and outgoing line beams are connected to the stiffening plates under the column top plates, the horizontal cross diagonal web members of the incoming and outgoing line beams located at the ends of the incoming and outgoing line beams are connected to the rod end connecting plates of the lower chord rods of the incoming and outgoing line beams, and the rod end connecting plates of the lower chord rods of the incoming and outgoing line beams are connected to the cantilevered corbel top plates on the steel pipe herringbone columns connected to the incoming and outgoing line beams.

[0009] The width of the busbar beam and the incoming and outgoing line beam ends is smaller than the width of the busbar beam and the incoming and outgoing line beam in the middle of the span.

[0010] When the incoming and outgoing line beams and busbar beams are connected to the steel pipe herringbone columns, beam end connecting plates are provided at the beam ends of the incoming and outgoing line beams and the busbar beams, and are bolted to the column top plate, the annular node plate, and the cantilevered corbel top plate through the beam end connecting plates, and circular holes are used on the beam end connecting plates.

[0011] The design method of the substation frame beam-column connection structure of the present invention has the following specific process:

[0012] Obtain boundary conditions, that is, obtain the peak acceleration value of the earthquake in the area where the substation project is located, the corresponding basic earthquake intensity, the characteristic period of the earthquake response spectrum, and the meteorological conditions in the area where the station is located;

[0013] Calculate the loads acting on the steel tube herringbone column joint frame;

[0014] The limit state design method is adopted to obtain the cross-sectional dimensions of the components of the transformer frame beam-column connection structure in combination with the load and boundary conditions, and then the transformer frame beam-column connection node and the overall structure are obtained.

[0015] When calculating the loads acting on the steel tube herringbone column combined frame, for the ultimate limit state of bearing capacity, the structure and components should be designed according to the basic combination of load effects; for the normal use limit state, the standard combination of loads should be used for design.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] When the inlet and outlet beams and busbar beams are fixedly connected to the steel tube herringbone columns, the forces are uniform at the mid-span and the supports of the beams, which is different from the hinged connection where the forces are the largest in the mid-span and the smallest at the supports. Therefore, the beam section is reduced accordingly, and the cross-section of each steel tube chord of the triangular lattice beam is reduced accordingly, and then the web of the beam is changed from slenderness ratio structural control to stability control, which improves the material utilization rate. The structure with fixed node type reduces the amount of steel compared with the structure with hinged node type; the inlet and outlet beams or busbar beams are fixedly connected to the steel tube herringbone columns, and the beams and columns can be synergistically stressed, which improves the integrity of the frame structure; when the inlet and outlet beams are fixedly connected to the steel tube herringbone columns, only the rod end connection plate of the upper chord of the inlet and outlet beams extends to the top plate of the column, which greatly reduces the size of the top plate of the column and the number of stiffeners, and at the same time facilitates the connection of the grounding column or lightning rod on the top plate of the column, avoiding the problem of the rod end connection plate of the lower chord of the inlet and outlet beam colliding with the grounding column or the base of the lightning rod when the inlet and outlet beams are hingedly connected to the steel tube herringbone columns.

[0018] Furthermore, when the incoming and outgoing line beams and the busbar beams are connected to the steel pipe herringbone columns, beam end connecting plates are provided at the beam ends of the incoming and outgoing line beams and the busbar beams, and are bolted to the column top plate, the annular node plate or the cantilevered corbel top plate through the beam end connecting plates, and circular holes are used on the beam end connecting plates; no relative slippage will occur between the beam ends and the supports, which can avoid the situation where the internal force redistribution is inconsistent with the elastic calculation model, and can accurately transmit the internal force of the frame beam ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the hinged connection nodes between the busbar beam, the incoming and outgoing line beams and the steel tube herringbone columns in a combined frame.

[0020] Figure 2 The figure is a schematic diagram of the connection nodes between the busbar beam, the incoming and outgoing line beams and the steel tube herringbone columns in a combined frame.

[0021] Figure 3a The present invention is a schematic diagram of a connection node fixing between a busbar beam and a steel pipe herringbone column in an implementable combined frame.

[0022] Figure 3b for Figure 3a Schematic diagram of the AA section.

[0023] Figure 3c for Figure 3a Schematic diagram of BB cross section.

[0024] Figure 4a The present invention is a schematic diagram of the connection node fixation between the inlet and outlet beams and the steel pipe herringbone columns in an implementable combined frame.

[0025] Figure 4b for Figure 4a Schematic diagram of CC cross section.

[0026] Figure 4c for Figure 4a Schematic diagram of DD cross section.

[0027] In the attached drawings, 1-inlet and outlet beam, 11-inlet and outlet beam upper chord, 12-inlet and outlet beam lower chord, 13-inlet and outlet beam vertical diagonal web member, 14-inlet and outlet beam horizontal cross diagonal web member, 2-busbar beam, 21-busbar beam upper chord, 22-busbar beam lower chord, 23-busbar beam vertical diagonal web member, 24-busbar beam horizontal cross diagonal web member, 3-herringbone column, 31-herringbone column top plate, 32-herringbone column annular node plate, 33-cantilevered corbel top plate connected to the inlet and outlet beam, 34-cantilevered corbel top plate connected to the busbar beam, 35-stiffening plate under the column top plate, 36-stiffening plate under the annular node plate of the herringbone column. DETAILED DESCRIPTION

[0028] A novel substation frame beam-column connection structure comprises a connection node between a busbar beam and a steel pipe herringbone column in a combined frame and a connection node between an inlet and outlet beam and a steel pipe herringbone column.

[0029] Referring to FIG3 , a substation frame beam-column connection structure includes an inlet and outlet beam 1, a busbar beam 2 and a steel tube herringbone column 3. The inlet and outlet beam 1 and the busbar beam 2 are both fixedly connected to the steel tube herringbone column 3. The inlet and outlet beam 1 and the busbar beam 2 are both triangular cross-section lattice beams. A steel tube herringbone column annular node plate 32 and a cantilevered corbel top plate are provided at the connection node of the steel tube herringbone column 3. The cantilevered corbel top plate includes a cantilevered corbel top plate 33 connected to the inlet and outlet beams. and a cantilevered corbel top plate 34 connected to the busbar beam; a stiffening plate 36 is arranged below the annular node plate of the steel tube herringbone column, a column top plate 31 is arranged at the top of the steel tube herringbone column, and a stiffening plate 35 is arranged below the column top plate; the inlet and outlet beam 1 is arranged above the busbar beam 2, and the busbar beam upper chord 21 and the busbar beam lower chord 22 are respectively connected to the steel tube herringbone column 3; the inlet and outlet beam upper chord 11 and the inlet and outlet beam lower chord 12 are respectively connected to the steel tube herringbone column 3.

[0030] The vertical diagonal web members 23 of the busbar beam at the end of the busbar beam are connected to the stiffening plate 36 below the annular node plate of the steel tube herringbone column, and the horizontal cross diagonal web members 24 of the busbar beam at the end of the busbar beam are connected to the rod end connection plate of the lower chord member 22 of the busbar beam, and the rod end connection plate of the lower chord member 22 of the busbar beam is further connected to the corbel top plate 34 cantilevered from the steel tube herringbone column.

[0031] The vertical diagonal web members 13 of the inlet and outlet beam at the end of the inlet and outlet beam are connected to the stiffening plate 35 under the column top plate, the horizontal cross diagonal web members 14 of the inlet and outlet beam at the end of the inlet and outlet beam are connected to the rod end connecting plate of the lower chord rod 12 of the inlet and outlet beam, and the rod end connecting plate of the lower chord rod 12 of the inlet and outlet beam is connected to the corbel top plate 33 cantilevered on the steel pipe herringbone column.

[0032] The widths of the busbar beam 2 and the incoming and outgoing line beam 1 at the beam ends are smaller than the widths of the busbar beam 2 and the incoming and outgoing line beam 1 in the middle of the span.

[0033] When the incoming and outgoing line beams 1 and the busbar beams 2 are connected to the steel pipe herringbone columns 3, beam end connecting plates are provided at the beam ends of the incoming and outgoing line beams 1 and the busbar beams 2, which are bolted to the column top plate 31, the annular node plate 32 or the cantilevered corbel top plate through the beam end connecting plates, and circular holes are used on the beam end connecting plates.

[0034] The cantilevered corbel on the steel tube herringbone column needs to have sufficient rigidity, and the connection calculation between it and the herringbone column must meet the requirements of the specification.

[0035] The design method of the substation frame beam-column connection structure of the present invention has the following specific process:

[0036] Obtain boundary conditions, that is, obtain the peak acceleration value of the earthquake in the area where the substation project is located, the corresponding basic earthquake intensity, the characteristic period of the earthquake response spectrum, and the meteorological conditions in the area where the station is located;

[0037] Calculate the loads acting on the steel tube herringbone column joint frame;

[0038] The limit state design method is adopted to obtain the cross-sectional dimensions of the components of the transformer frame beam-column connection structure in combination with the load and boundary conditions, and then the transformer frame beam-column connection node and the overall structure are obtained.

[0039] At the connection nodes between the incoming and outgoing line beams and busbar beam chords and the steel tube herringbone columns, the steel tube wall of the herringbone column is subjected to large local stress transmitted from the beam connecting plate, and the converted stress under the three-dimensional stress state needs to be verified.

[0040] The fixed connection nodes in the combined frame include the connection nodes between the busbar beam and the steel tube herringbone column and the connection nodes between the incoming and outgoing line beam and the steel tube herringbone column.

[0041] 1) Connection node between busbar beam and steel tube herringbone column in joint frame. The plane of steel tube herringbone column 3 is regarded as an integral rigid frame column, which is integrally fixed to the busbar beam 2 of triangular cross-section lattice. Cross steel tube web members are arranged within the height range of busbar beam in the plane of steel tube herringbone column 3. In order to ensure the local stability of steel tube column at the connection between busbar beam 2 and steel tube herringbone column 3, a through stiffening plate is arranged in the steel tube column. The width of the busbar beam end is narrowed, while the height remains unchanged. The rod end connection plate of the busbar beam upper chord 21 is bolted to the annular node plate 32 of the steel tube herringbone column 3. The vertical diagonal web member 23 of the busbar beam at the beam end is connected to the stiffening plate 36 below the annular node plate of the steel tube herringbone column. The horizontal cross diagonal web member 24 of the busbar beam at the beam end is connected to the rod end connection plate of the busbar beam lower chord 22. The rod end connection plate of the busbar beam lower chord 22 is bolted to the cantilevered corbel top plate 34 on the steel tube herringbone column connected to the busbar beam. The stiffness of the cantilevered corbel directly affects the magnitude of the bending moment at the mid-span of the busbar beam. In order to make the busbar beam upper chord 21 and the busbar beam lower chord 22 more evenly stressed at the mid-span and support, a cantilevered corbel with sufficient stiffness is required and the connection calculation between it and the herringbone column meets the requirements of the specification. The steel tube wall of the steel tube herringbone column is subjected to large local stress transmitted from the beam connection plate, and the converted stress under the three-dimensional stress state needs to be verified. Reference Figure 3a , Figure 3b as well as Figure 3c .

[0042] 2) Connection node between the inlet and outlet beam and the steel tube herringbone column. The steel tube herringbone column 3 is regarded as an integral double-tube column outside the plane, and is integrally fixed to the triangular cross-section lattice inlet and outlet beam 1. The width of the inlet and outlet beam end is narrowed, and the height remains unchanged. The rod end connection plate of the upper chord rod 11 of the inlet and outlet beam is bolted to the column top plate 31. The vertical diagonal web rod 13 of the inlet and outlet beam at the beam end is connected to the stiffening plate 35 under the column top plate. The horizontal cross diagonal web rod 14 of the inlet and outlet beam at the beam end is connected to the rod end connection plate of the lower chord rod 12 of the inlet and outlet beam. The rod end connection plate of the lower chord rod 12 of the inlet and outlet beam is then bolted to the cantilevered corbel top plate 33 on the steel tube herringbone column 3 connected to the inlet and outlet beam. The stiffness of the cantilevered corbel directly affects the size of the mid-span bending moment of the inlet and outlet beam. In order to make the upper chord 11 and the lower chord 12 of the incoming and outgoing line beam bear more uniform forces at the mid-span and the support, a cantilevered corbel with sufficient rigidity is required and the connection calculation between it and the steel tube herringbone column 3 must meet the requirements of the specification. At the connection between the lower chord 12 of the incoming and outgoing line beam and the steel tube herringbone column 3, the steel tube wall of the steel tube herringbone column is subjected to large local stress transmitted from the beam connection plate, and the converted stress under the three-dimensional stress state needs to be verified. When the incoming and outgoing line beam 1 is fixedly connected to the steel tube herringbone column 3, only the rod end connection plate of the upper chord 11 of the incoming and outgoing line beam extends to the column top plate 31, which greatly reduces the size of the column top plate and the number of stiffening plates, and at the same time facilitates the connection of the grounding column or lightning rod on the column top plate. This avoids the problem of the rod end connection plate of the lower chord of the incoming and outgoing line beam colliding with the grounding column or the base of the lightning rod when the incoming and outgoing line beam is hingedly connected to the steel tube herringbone column. Refer to Figure 4a , Figure 4b as well as Figure 4c .

[0043] The structural design of integrally fixed connection between triangular-section lattice beams and steel tube herringbone columns in the combined frame is a first at home and abroad.

[0044] Combined with the general layout of the 750kV frame in a new 750kV substation project and the conductor tension under various load conditions, the spatial bar analysis software STAAD Pro (V8i) was used to establish an overall model of the 750kV frame for spatial calculation. The fixed nodes and hinged nodes of the steel tube herringbone column combined frame beam-column were calculated and compared respectively, and the optimal node structure type was proposed.

[0045] The same boundary conditions are input into the two structural models: 1) basic wind pressure, 2) peak acceleration value of seismic motion in the station area, the corresponding basic earthquake intensity, and the characteristic period of the seismic response spectrum, and 3) other meteorological conditions in the area where the station is located.

[0046] Calculate load (or action)

[0047] The loads acting on the steel tube herringbone column joint frame mainly include: conductor (ground) wire tension, structural deadweight, wind load, ice load, temporary load generated by installation and maintenance, temperature effect and earthquake effect. The loads generated by the final scale are analyzed and calculated.

[0048] The conductor tension is provided by the electrical engineering department, and the conductor ice load is considered by the electrical engineering department in the conductor tension.

[0049] Wind load has a great impact on the substation structure. According to the requirements of the current national standard "High-rise Structure Design Code" GB50135, the effects of 0-degree and 90-degree wind (i.e. wind along the conductor and vertical conductor) on the structure are considered. The basic natural vibration period of general structures is T≥0.25s. The structural vibration caused by wind is relatively obvious, and as the natural vibration period of the structure increases, the wind vibration also increases. Therefore, the influence of wind vibration should be considered during design. The wind vibration coefficient βz in the "Technical Regulations for the Structural Design of Overhead Transmission Line Towers" DL / T5154 is for self-supporting iron towers. When the total height does not exceed 60m, a coefficient is used for the total height.

[0050] For relatively high and flexible frame structures, the impact of wind vibration is generally greater than that of earthquakes. However, if the weight of the structure is large and it is located in a high-intensity earthquake zone, the impact of the earthquake will be stronger. Therefore, structures built in high-intensity earthquake zones should fully consider the impact of earthquakes to ensure the safety of the structure. The "Code for Seismic Design of Buildings" GB50011 stipulates that for tall structures in areas with an intensity of 8 or above, vertical earthquake effects should be calculated. Both horizontal and vertical earthquake effects are calculated using the response spectrum method.

[0051] For structures exposed outdoors, they are directly affected by temperature. At the same time, the longitudinal dimensions of the structure are large, and the cumulative effect of temperature effect is obvious. The Technical Code for Design of Substation Building Structures DL / T 5457 stipulates that the influence of temperature effect should be calculated for continuous racks with rigid supports at both ends with a total length of more than 150m, or continuous rigid frames with a total length of more than 100m. When calculating the temperature effect, the temperature difference should be reasonably selected according to the specific conditions of the project.

[0052] Load (or action) combination

[0053] The 750kV combined frame is designed using the limit state design method, namely the bearing capacity limit state and the normal use limit state. The bearing capacity limit state corresponds to the deformation of the structure or structural member reaching the maximum bearing capacity or being unsuitable for continued bearing, and the normal use limit state corresponds to the structure or structural member reaching a certain specified limit of normal use or durability performance.

[0054] 1) For the ultimate limit state of bearing capacity, structures and components should be designed according to the basic combination of load effects.

[0055] 2) For the serviceability limit state, the standard combination of loads is used for design.

[0056] Control conditions for normal use limit state: the allowable deflection value of the column top for the in-plane and out-plane (with end braces) of the steel tube herringbone column is h / 200 (h is the height of the column calculation point), and the mid-span of the beam is L / 400 (L is the span of the beam).

[0057] Computational model

[0058] The 750kV frame adopts a combined frame, a steel tube herringbone column + a triangular cross-section lattice beam structure. The calculation models of the incoming and outgoing line beams and busbar beams and the steel tube herringbone columns are respectively hinged and fixed. Figure 1 and Figure 2 .

[0059] Determination of the calculated length of steel pipe herringbone columns

[0060] 1) The inlet and outlet beams and busbar beams are hingedly connected to the steel pipe herringbone columns

[0061] First, the steel tube herringbone column is regarded as an integral rigid frame column, which is hinged with the busbar beam in the plane. The calculated length coefficient of the frame column without lateral displacement is obtained, and the horizontal beam line stiffness is taken as zero, k1=0, k2=10, and μ1=0.732 is obtained. The overall slenderness ratio of the lower column is λ1=μ1*L1 / i1, where L1=31.5m, and the rotation radius of the overall section of the connection between the steel tube herringbone column and the busbar beam to the longitudinal axis is taken as i1; the upper column is a cantilever column, μ1=2.0, and the overall slenderness ratio λ1=μ1*L1 / i1, where L1=11.5m, and the rotation radius of the overall section of the column head of the steel tube herringbone column to the longitudinal axis is taken as i1. Secondly, the stability of the column limb in the plane of the steel tube herringbone column is calculated, and the length coefficient μ2 is calculated as 0.7 and 1.0 from the lower section to the upper section. The steel tube herringbone column is hinged with the inlet and outlet beams outside the plane, and the end brace is set at the end. First, the steel tube herringbone column is regarded as an integral double-tube column. According to the calculation length coefficient of the frame column without lateral displacement, the crossbeam line stiffness is taken as zero, k1=0, k2=10, and μ2=0.732 is obtained. The overall slenderness ratio λ2=μ2*L2 / i2, where L2=43.0m, i2 is the gyration radius of the overall section of the steel tube herringbone column to the horizontal axis. Secondly, the stability of the column limb of the steel tube herringbone column outside the plane is calculated, and the length coefficient μ3=0.5, L3=43.0m, i3 is the gyration radius of the column limb section of the steel tube herringbone column is calculated.

[0062] 2) The inlet and outlet beams and busbar beams are connected to the steel pipe herringbone columns by fixed connection

[0063] First, the steel tube herringbone column is regarded as an integral rigid frame column, which is fixedly connected to the busbar beam in the plane. The calculated length coefficient is obtained according to the non-lateral displacement frame column. k1 is the ratio of the sum of the stiffness of the beam line intersecting at the upper end of the column to the sum of the stiffness of the column line. When the far end of the beam is hinged, the stiffness of the beam line should be multiplied by 1.5. When the far end of the beam is embedded, the stiffness of the beam line should be multiplied by 2.0. It can be seen that k1 is larger when the beam is fixed to the column. When the k2 value is constant, the calculated length coefficient μ value is smaller. The conservative lower column line stiffness is calculated by the moment of inertia of the overall section of the steel tube herringbone column at the foot of the column to the longitudinal axis, and the upper column line stiffness is calculated by the moment of inertia of the overall section of the steel tube herringbone column at the connection with the busbar beam to the longitudinal axis. In this way, the sum of the column line stiffness is larger, k1 is smaller, and the μ value found is larger. After calculation, k1=0.03, when k2=10, μ1=0.728 is obtained, which is smaller than the calculated length coefficient of the lower column in 1); the overall slenderness ratio calculation of the upper column and the stability calculation of the column limbs in the plane of the steel tube herringbone column are the same as 1). The steel tube herringbone column is fixedly connected to the inlet and outlet line beams outside the plane, and the end braces are set at the ends. The steel tube herringbone column is regarded as an integral double-tube column. After calculation, k1=18.89, when k2=10, according to the calculated length coefficient of the frame column without lateral displacement, μ2=0.549 is obtained, which is much smaller than the overall calculated length coefficient of the out-of-plane steel tube herringbone column in 1). The stability calculation of the column limbs of the out-of-plane steel tube herringbone column is the same as 1).

[0064] From the above comparison, it can be seen that the reduction of the overall calculated length coefficient of the steel tube herringbone column in the plane fixed connection with the busbar beam is not very obvious compared with the hinged connection, but the overall calculated length coefficient of the steel tube herringbone column fixed connection with the inlet and outlet beam out of the plane is reduced more than the hinged connection. Whether out of the plane or in the plane, the overall calculated length coefficient of the steel tube herringbone column fixed connection is reduced compared with the hinged connection, and the corresponding column section size is also reduced.

[0065] Refer to the box section formula and the "Steel Structure Design Manual" to calculate the local stability of the steel tube column limbs.

[0066] Comparison of calculation results

[0067] Through structural calculation of two types of nodes, the cross-sectional dimensions of the components and the cross-section of the main materials are shown in Table 1.

[0068] Table 1 Structural member cross-sectional dimensions and main material cross-sectional dimensions of two types of nodes

[0069]

[0070]

[0071] The in-and-out line beams and the steel tube herringbone columns are fixedly connected, and the upper and lower sections of the steel tube herringbone columns are evenly stressed, which is different from the hinged connection where the column foot is subjected to the greatest stress; since each steel tube herringbone column shares most of the longitudinal force of the frame, the longitudinal force shared by the end support column is much smaller, which is different from the hinged connection where the end support column bears most of the longitudinal force of the frame, and the cross section of the end support column is reduced the most. The busbar beam and the steel tube herringbone column are fixedly connected, and the steel tube herringbone column is subjected to stress as a whole, which is different from the hinged connection where only the column limb connected to the busbar beam is subjected to great stress while the column limb on the opposite side is subjected to small stress. Therefore, when the frame beam and the steel tube herringbone column are fixedly connected, the column cross section is correspondingly reduced.

[0072] When the inlet and outlet beams and busbar beams are fixedly connected to the steel tube herringbone columns, the forces are evenly distributed at the mid-span and the supports, which is different from the hinged connection where the forces are the largest at the mid-span and the smallest at the supports. Therefore, the beam section is reduced accordingly, and the cross-section of each steel tube chord of the triangular lattice beam is reduced accordingly. Due to the reduction in the beam section, the web of the beam is changed from the original slenderness ratio structural control to stable control, which improves the material utilization rate. Statistics on the amount of structural steel of the two node types show that the structure with fixed node type reduces the amount of steel by about 18% compared with the structure with hinged node type. When the inlet and outlet beams or busbar beams are fixedly connected to the steel tube herringbone columns, the beams and columns can be synergistically stressed, improving the integrity of the frame structure.

[0073] Design of fixed joints for steel pipe herringbone column joint frame

[0074] It includes two situations: the connection node between the busbar beam and the steel tube herringbone column in the combined frame and the connection node between the incoming and outgoing line beam and the steel tube herringbone column.

[0075] (1) The connection node between the busbar beam and the steel tube herringbone column in the combined frame. The steel tube herringbone column is regarded as an integral rigid frame column in the plane, and is integrally fixed to the triangular cross-section lattice beam. A cross steel tube web member is set within the height range of the busbar beam in the plane of the steel tube herringbone column. In order to ensure the local stability of the steel tube column at the connection between the busbar beam and the steel tube herringbone column, a through radial stiffener is set in the steel tube column. The width of the busbar beam end is narrowed, and the height remains unchanged. The upper chord rod end connection plate of the busbar beam is bolted to the annular node plate of the steel tube herringbone column. The vertical diagonal web of the busbar beam at the beam end is connected to the stiffening plate below the annular node plate of the steel tube herringbone column. The horizontal cross diagonal web at the end of the busbar beam is connected to the lower chord rod end connection plate. The lower chord rod end connection plate of the busbar beam is then bolted to the cantilevered corbel top plate on the steel tube herringbone column. The stiffness of the cantilevered corbel directly affects the size of the mid-span bending moment of the busbar beam. The smaller the stiffness of the cantilevered corbel, the greater the mid-span bending moment of the busbar beam, and the less obvious the synergistic effect between the busbar beam and the steel tube herringbone column, which is almost hinged to the steel tube herringbone column. In order to make the upper and lower chords of the busbar beam more evenly stressed at the mid-span and support, a cantilevered corbel with sufficient stiffness is required, and the connection calculation between it and the steel tube herringbone column meets the requirements of the specification. At the connection between the busbar beam chord and the steel tube herringbone column, the steel tube wall of the steel tube herringbone column is subjected to large local stress transmitted from the beam connection plate, and the converted stress under the three-dimensional stress state needs to be verified. Figure 3a , Figure 3b as well as Figure 3c The number of bolts in the figure is for reference only.

[0076] (2) The connection node between the inlet and outlet beam and the steel tube herringbone column. The steel tube herringbone column is regarded as an integral double-tube column outside the plane, and is integrally fixed to the triangular cross-section lattice beam. The width of the inlet and outlet beam end is narrowed, and the height remains unchanged. The rod end connection plate of the upper chord of the inlet and outlet beam is bolted to the column top plate. The vertical diagonal web of the inlet and outlet beam at the beam end is connected to the stiffening plate under the column top plate. The horizontal cross diagonal web at the end of the inlet and outlet beam is connected to the rod end connection plate of the lower chord of the inlet and outlet beam. The rod end connection plate of the lower chord of the inlet and outlet beam is then bolted to the top plate of the cantilevered corbel on the steel tube herringbone column. The stiffness of the cantilevered corbel directly affects the size of the mid-span bending moment of the inlet and outlet beam. The smaller the stiffness of the cantilevered corbel, the larger the mid-span bending moment of the inlet and outlet beam, and the less obvious the synergistic effect between the inlet and outlet beam and the steel tube herringbone column, which is almost hinged to the steel tube herringbone column. In order to make the upper and lower chords of the incoming and outgoing line beams more evenly stressed at the mid-span and the supports, cantilevered corbels with sufficient rigidity are required and the calculation of their connection with the steel tube herringbone column must meet the requirements of the specifications. At the connection between the lower chord of the incoming and outgoing line beam and the steel tube herringbone column, the steel tube wall of the steel tube herringbone column is subjected to large local stress transmitted from the beam connection plate, and the converted stress under the three-dimensional stress state needs to be verified. When the incoming and outgoing line beam is fixedly connected to the steel tube herringbone column, only the rod end connection plate of the upper chord of the incoming and outgoing line beam extends to the column top plate, which greatly reduces the size of the column top plate and the number of stiffening plates, and facilitates the connection of the grounding column or lightning rod on the column top plate. This avoids the problem of the rod end connection plate of the lower chord of the beam colliding with the grounding column or the base of the lightning rod when the incoming and outgoing line beam and the steel tube herringbone column are hingedly connected. See the fixed connection node between the incoming and outgoing line beam and the steel tube herringbone column. Figure 4a , Figure 4b as well as Figure 4c The number of bolts in the figure is for reference only.

[0077] When the incoming and outgoing line beams and busbar beams are hinged to the steel tube herringbone columns, elliptical holes are used at the beam supports for easy installation. The length of the holes is along the length of the beam. Relative slip is allowed between the ends of the frame beams and the supports. The temperature stress of each span has been partially released. The STAAD model cannot accurately simulate this state, and the calculated temperature stress is larger than the actual force. When the incoming and outgoing line beams and busbar beams are fixed to the steel tube herringbone columns, circular holes are used at the beam supports to transfer the internal forces at the ends of the frame beams. Relative slip is not allowed between the ends of the beams and the supports to avoid the situation where the redistribution of internal forces is inconsistent with the elastic calculation model. The STAAD model can accurately simulate the actual temperature stress state of the structure. However, the use of circular holes places higher requirements on the processing accuracy of the frame beams.

[0078] In the 750kV distribution device area using the HGIS layout scheme, in order to improve the permeability of the entire distribution device area and save steel, the frame columns use steel tube herringbone columns, the frame beams use triangular cross-section lattice beams, and the beams and columns are fixedly connected, which reduces the overall calculation length coefficient of the steel tube herringbone columns, further reduces the column section and beam section, and improves the material utilization rate of the beam web. The structure using the fixed node type reduces the amount of steel by about 18% compared to the structure using the hinged node type. Moreover, after the beams and columns use the fixed node, the integrity and safety reserve of the entire joint frame are effectively improved.

[0079] Whether it is an inlet and outlet beam or a busbar beam, in order to make the upper and lower chords of the busbar beam or the inlet and outlet beam more evenly stressed at the mid-span and the support, a cantilevered corbel with sufficient rigidity is required and the connection calculation between it and the steel tube herringbone column must meet the requirements of the specification. At the connection between the upper and lower chords of the busbar beam and the lower chord of the inlet and outlet beam and the steel tube herringbone column, the steel tube wall of the steel tube herringbone column is subjected to large local stress transmitted from the beam connection plate, and the converted stress under the three-dimensional stress state needs to be verified. When the inlet and outlet beam is fixedly connected to the steel tube herringbone column, only the connecting plate at the end of the upper chord of the inlet and outlet beam extends to the top plate of the column, which greatly reduces the size of the top plate of the column and the number of stiffeners, and at the same time facilitates the connection of the grounding column or lightning rod on the top plate of the column.

[0080] In order to accurately transmit the internal forces at the ends of the frame beams, circular holes are used at the beam supports. No relative slippage is allowed between the beam ends and the supports to avoid the situation where the redistribution of internal forces is inconsistent with the elastic calculation model.

Claims

1. A substation frame beam-column connection structure, characterized in that: The invention comprises an inlet and outlet beam (1), a busbar beam (2) and a steel tube herringbone column (3), wherein the inlet and outlet beam (1) and the busbar beam (2) are both fixedly connected to the steel tube herringbone column (3); the inlet and outlet beam (1) and the busbar beam (2) are both lattice beams with triangular cross-sections; a steel tube herringbone column annular node plate (32) and a cantilevered corbel top plate are provided at the connection node of the steel tube herringbone column (3); the cantilevered corbel top plate comprises a cantilevered corbel top plate (33) connected to the inlet and outlet beam and a cantilevered corbel top plate (34) connected to the busbar beam; A stiffening plate (36) is arranged below the annular node plate of the steel tube herringbone column, a column top plate (31) is arranged at the top of the steel tube herringbone column, and a stiffening plate (35) is arranged below the column top plate; an inlet and outlet beam (1) is arranged above the busbar beam (2); the busbar beam upper chord rod (21) and the busbar beam lower chord rod (22) are respectively connected to the steel tube herringbone column (3); the inlet and outlet beam upper chord rod (11) and the inlet and outlet beam lower chord rod (12) are respectively connected to the steel tube herringbone column (3); the inlet and outlet beam upper chord rod (11) is connected to the column top plate through a rod end connection plate; The busbar (2) is connected to the plate (31); a cross steel tube web member is arranged within the height range of the busbar beam (2) in the plane of the steel tube herringbone column (3); the busbar beam vertical diagonal web member (23) at the end of the busbar beam is connected to the stiffening plate (36) below the annular node plate of the steel tube herringbone column, the busbar beam horizontal cross diagonal web member (24) at the end of the busbar beam is connected to the rod end connection plate of the busbar beam lower chord member (22), and the rod end connection plate of the busbar beam lower chord member (22) is further connected to the cantilevered corbel top plate (34) on the steel tube herringbone column connected to the busbar beam; The vertical diagonal web members (13) of the inlet and outlet beams at the ends of the inlet and outlet beams are connected to the stiffening plates (35) under the column top plates, the horizontal cross diagonal web members (14) of the inlet and outlet beams at the ends of the inlet and outlet beams are connected to the rod end connection plates of the lower chord rods (12) of the inlet and outlet beams, and the rod end connection plates of the lower chord rods (12) of the inlet and outlet beams are connected to the cantilevered corbel top plates (33) on the steel pipe herringbone columns connected to the inlet and outlet beams; the widths of the busbar beams (2) and the inlet and outlet beams (1) at the ends of the beams are smaller than the widths of the busbar beams (2) and the inlet and outlet beams (1) in the middle of the spans.

2. The substation frame beam-column connection structure according to claim 1, characterized in that: The stiffening plate passes through the steel pipe of the steel pipe herringbone column (3).

3. The substation frame beam-column connection structure according to claim 1, characterized in that: When the inlet and outlet beams (1) and the busbar beams (2) are connected to the steel tube herringbone columns (3), beam end connection plates are provided at the beam ends of the inlet and outlet beams (1) and the busbar beams (2), and the beam end connection plates are bolted to the column top plate (31), the annular node plate (32), and the cantilevered corbel top plate, and circular holes are used on the beam end connection plates.

4. The design method of the substation frame beam-column connection structure according to claims 1 to 3 is characterized in that: The specific process is as follows: Obtain boundary conditions, that is, obtain the peak acceleration value of the earthquake in the area where the substation project is located, the corresponding basic earthquake intensity, the characteristic period of the earthquake response spectrum, and the meteorological conditions in the area where the station is located; Calculate the loads acting on the steel tube herringbone column joint frame; The limit state design method is adopted to obtain the cross-sectional dimensions of the components of the transformer frame beam-column connection structure in combination with the load and boundary conditions, and then the transformer frame beam-column connection node and the overall structure are obtained.

5. The design method according to claim 4, characterized in that: When calculating the loads acting on the steel tube herringbone column combined frame, for the ultimate limit state of bearing capacity, the structure and components should be designed according to the basic combination of load effects; for the normal use limit state, the standard combination of loads should be used for design.

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