1. A beam-column connecting structure of a power transformation framework is characterized by comprising an inlet and outlet beam (1), a bus beam (2) and a steel pipe herringbone column (3), wherein the inlet and outlet beam (1) and the bus beam (2) are fixedly connected with the steel pipe herringbone column (3); the wire inlet and outlet beam (1) and the bus beam (2) both adopt lattice beams with triangular sections; the method comprises the following steps that a steel pipe herringbone column annular gusset plate (32) and an overhanging bracket top plate are arranged at a connection node of a steel pipe herringbone column (3), the overhanging bracket top plate comprises an overhanging bracket top plate (33) connected with an incoming and outgoing line beam and an overhanging bracket top plate (34) connected with a bus beam, a stiffening plate (36) is arranged below the steel pipe herringbone column annular gusset plate, a column top plate (31) is arranged at the top end of the steel pipe herringbone column, a stiffening plate (35) is arranged below the column top plate, the incoming and outgoing line beam (1) is arranged above the bus beam (2), and an upper chord (21) and a lower chord (22) of the bus beam are respectively connected with the steel pipe herringbone column (3); the upper chord (11) of the incoming and outgoing line beam and the lower chord (12) of the incoming and outgoing line beam are respectively connected with the steel pipe herringbone columns (3); the upper chord (11) of the incoming and outgoing line beam is connected with the column top plate (31) through a rod end connecting plate.

2. A transformation frame beam column connection structure according to claim 1, characterized in that crossed steel tube web members are provided within the height range of the bus beam (2) in the plane of the steel tube herringbone column (3).

3. A transformation frame beam column connection structure according to claim 2, characterized in that the stiffening plates penetrate through the steel tubes of the steel tube herringbone columns (3).

4. A transformation frame beam column connection structure according to claim 1, characterized in that the vertical diagonal web members (23) of the bus bar beam at the bus bar beam end are connected to stiffening plates (36) below the ring-shaped gusset plates of the steel pipe herringbone columns, the horizontal crossing diagonal web members (24) of the bus bar beam at the bus bar beam end are connected to the rod end connection plates of the lower chord members (22) of the bus bar beam, and the rod end connection plates of the lower chord members (22) of the bus bar beam are further connected to the cantilever corbel top plates (34) of the steel pipe herringbone columns connected to the bus bar beam.

5. A transformation frame beam column connection structure according to claim 1, characterized in that the vertical diagonal web members (13) of the in-out line beam at the beam end of the in-out line beam are connected to the stiffening plate (35) below the column top plate, the horizontal crossing diagonal web members (14) of the in-out line beam at the beam end of the in-out line beam are connected to the rod end connection plates of the lower chord members (12) of the in-out line beam, and the rod end connection plates of the lower chord members (12) of the in-out line beam are connected to the cantilever corbel top plate (33) of the steel tube herringbone column connected to the in-out line beam.

6. A transformation frame beam column connection according to claim 1, characterized in that the width of the ends of the busbar beam (2) and the access beam (1) is smaller than the width of the mid-span of the busbar beam (2) and the access beam (1).

7. A transformation framework beam-column connection structure as claimed in claim 1, wherein when the line access beam (1) and the bus bar beam (2) are connected with the steel pipe herringbone column (3), beam end connection plates are arranged at the beam ends of the line access beam (1) and the bus bar beam (2), and are connected with the column top plate (31), the annular node plate (32) and the cantilever bracket top plate through bolts, and round holes are arranged on the beam end connection plates.

8. The design method of the power transformation framework beam-column connecting structure disclosed by claim 1-7 is characterized by comprising the following specific processes:

acquiring boundary conditions, namely acquiring the earthquake motion peak acceleration value of the area where the transformer substation engineering is located, the corresponding earthquake basic intensity, the earthquake motion response spectrum characteristic period and the meteorological conditions of the area where the station site is located;

calculating the load acting on the steel pipe herringbone column combined framework;

and obtaining the member section size of the beam-column connection structure of the power transformation framework by adopting a limit state design method and combining the load and the boundary conditions, thereby obtaining the beam-column connection node and the whole structure of the power transformation framework.

9. The design method according to claim 8, wherein when calculating the load acting on the steel pipe herringbone column combined framework, the structure and the component are designed according to the basic combination of load effect for the load-bearing capacity limit state; for normal use limit conditions, the design is made using a standard combination of loads.

Background

750kV distribution equipment areas in new construction of 750kV transformer substations adopt HGIS arrangement schemes, 750kV combined frameworks are composed of incoming and outgoing line beams, bus beams and steel pipe herringbone columns, the bus beams are vertically arranged with the incoming and outgoing line beams, the span of the incoming and outgoing line beams is 41.0m, the height of a hanging line is 42.5m, the span of the bus beams is 42.5m, and the height of the hanging line is 31.0 m. The combined framework column adopts a steel pipe herringbone column, the combined framework beam adopts a lattice beam with a triangular section, and the beam column is hinged. The whole structure has poor stress cooperativity and integrity and low material utilization rate.

Disclosure of Invention

Aiming at the connection node type of a large-span triangular lattice beam and a steel pipe herringbone column in a combined framework of a transformer substation, the beam column is fixedly connected from the aspects of structural stress, structural requirements and the like, and the structural type of fixedly connecting the large-span triangular section lattice beam and the steel pipe herringbone column is adopted, so that the aims of fully utilizing the mechanical characteristics of high tensile and compression bending strength and good toughness of steel and reducing the structural cost are fulfilled.

In order to achieve the purpose, the invention adopts the technical scheme that: a beam-column connecting structure of a power transformation framework comprises an inlet and outlet line beam, a bus beam and a steel pipe herringbone column, wherein the inlet and outlet line beam and the bus beam are fixedly connected with the steel pipe herringbone column; the wire inlet and outlet beams and the bus beams are all triangular section lattice beams; the method comprises the following steps that a steel pipe herringbone column annular node plate and an overhanging bracket top plate are arranged at a connecting node of the steel pipe herringbone column, the overhanging bracket top plate comprises an overhanging bracket top plate connected with a line inlet and outlet beam and an overhanging bracket top plate connected with a bus beam, a stiffening plate is arranged below the steel pipe herringbone column annular node plate, a column top plate is arranged at the top end of the steel pipe herringbone column, a stiffening plate is arranged below the column top plate, the line inlet and outlet beam is arranged above the bus beam, and an upper chord of the bus beam and a lower chord of the bus beam are respectively connected with the steel pipe herringbone column; the upper chord of the line inlet and outlet beam and the lower chord of the line inlet and outlet beam are respectively connected with the steel pipe herringbone columns; the upper chord of the incoming and outgoing line beam is connected with the column top plate through the rod end connecting plate.

Crossed steel pipe web members are arranged in the height range of the bus beam in the plane of the steel pipe herringbone column.

The stiffening plate penetrates through the steel pipe of the steel pipe herringbone column.

The vertical diagonal web members of the bus beams at the ends of the bus beams are connected with the stiffening plates below the annular gusset plates of the steel pipe herringbone columns, the horizontal crossed diagonal web members of the bus beams at the ends of the bus beams are connected to the rod end connecting plates of the lower chord members of the bus beams, and the rod end connecting plates of the lower chord members of the bus beams are connected with cantilever corbel top plates connected with the bus beams on the steel pipe herringbone columns.

The vertical diagonal web members of the inlet and outlet line beams at the ends of the inlet and outlet line beams are connected with the stiffening plates below the column top plate, the horizontal crossed diagonal web members of the inlet and outlet line beams at the ends of the inlet and outlet line beams are connected to the rod end connecting plates of the lower chord members of the inlet and outlet line beams, and the rod end connecting plates of the lower chord members of the inlet and outlet line beams are connected with the cantilever bracket top plate connected with the inlet and outlet line beams on the steel pipe herringbone columns.

The width of the ends of the bus beam and the line inlet and outlet beam is less than the width of the span of the bus beam and the line inlet and outlet beam.

When the incoming and outgoing line beam and the bus beam are connected with the steel pipe herringbone column, beam end connecting plates are arranged at the beam ends of the incoming and outgoing line beam and the bus beam, and are connected with the column top plate, the annular node plate and the cantilever bracket top plate through bolts, and round holes are formed in the beam end connecting plates.

The invention relates to a design method of a beam-column connecting structure of a power transformation framework, which comprises the following specific processes:

acquiring boundary conditions, namely acquiring the earthquake motion peak acceleration value of the area where the transformer substation engineering is located, the corresponding earthquake basic intensity, the earthquake motion response spectrum characteristic period and the meteorological conditions of the area where the station site is located;

calculating the load acting on the steel pipe herringbone column combined framework;

and obtaining the member section size of the beam-column connection structure of the power transformation framework by adopting a limit state design method and combining the load and the boundary conditions, thereby obtaining the beam-column connection node and the whole structure of the power transformation framework.

When the load acting on the steel pipe herringbone column combined framework is calculated, the structure and the components are designed according to the basic combination of the load effect for the bearing capacity limit state; for normal use limit conditions, the design is made using a standard combination of loads.

Compared with the prior art, the invention has at least the following beneficial effects:

when the incoming and outgoing line beam and the bus beam are fixedly connected with the steel pipe herringbone column, the stress in the beam span and the support seat is uniform, the maximum stress in the beam span and the minimum stress on the support seat are different from the maximum stress in the beam span and the minimum stress on the support seat in the hinged connection, so that the beam section is correspondingly reduced, the section of each steel pipe chord member of the triangular lattice beam is correspondingly reduced, the control of the beam web member is changed from the length-thin ratio structure control into the stable control, the material utilization rate is improved, and the steel amount is reduced by adopting a fixedly connected node type structure compared with a hinged node type structure; the incoming and outgoing line beams or the bus beams are fixedly connected with the steel pipe herringbone columns, and the beam columns can be stressed cooperatively, so that the integrity of the framework structure is improved; when the incoming and outgoing line beam is fixedly connected with the steel pipe herringbone column, only the upper chord rod end connecting plate of the incoming and outgoing line beam extends to the column top plate, so that the size of the column top plate and the number of stiffening plates are greatly reduced, meanwhile, the ground line column or the lightning rod is conveniently connected on the column top plate, and the problem that the lower chord rod end connecting plate of the incoming and outgoing line beam collides with the ground line column or the lightning rod base when the incoming and outgoing line beam is hinged with the steel pipe herringbone column is solved.

Furthermore, when the line inlet and outlet beam and the bus beam are connected with the steel pipe herringbone column, beam end connecting plates are arranged at the beam ends of the line inlet and outlet beam and the bus beam, and are connected with a column top plate, an annular node plate or an overhanging bracket top plate through the beam end connecting plates by bolts, and circular holes are adopted on the beam end connecting plates; the beam end and the support cannot slide relatively, so that the situation that the inner force redistribution is inconsistent with the elastic calculation model can be avoided, and the inner force of the beam end of the framework can be accurately transmitted.

Drawings

FIG. 1 is a schematic view of the articulation of the connection nodes of a bus beam, an inlet and outlet line beam and a steel pipe herringbone column in a combined framework.

FIG. 2 is a schematic view of the connection joint connection between the busbar beam and the inlet and outlet beam of the combined framework and the steel pipe herringbone column.

FIG. 3a is a schematic view of the connection joint of the busbar beam and the steel pipe herringbone post in the practical combined framework of the present invention.

Fig. 3b is a schematic cross-sectional view a-a of fig. 3 a.

FIG. 3c is a schematic cross-sectional view B-B of FIG. 3 a.

FIG. 4a is a schematic view of the connection joint of the inlet and outlet beams and the steel pipe herringbone columns in the practical combined framework.

Fig. 4b is a schematic cross-sectional view C-C of fig. 4 a.

Fig. 4c is a schematic cross-sectional view of fig. 4a taken along line D-D.

In the attached drawing, 1-an in-out line beam, 11-an in-out line beam upper chord, 12-an in-out line beam lower chord, 13-an in-out line beam vertical diagonal web members, 14-an in-out line beam horizontal cross diagonal web members, 2-bus bar beams, 21-bus bar beam upper chord members, 22-bus bar beam lower chord members, 23-bus bar beam vertical diagonal web members, 24-bus bar beam horizontal cross diagonal web members, 3-herringbone columns, 31-herringbone column top plates, 32-herringbone column annular node plates, 33-cantilever corbel top plates connected with the in-out line beam, 34-cantilever corbel top plates connected with the bus bar beam, stiffening plates below 35-column top plates and stiffening plates below 36-herringbone column annular node plates.

Detailed Description

A novel beam column connecting structure of a power transformation framework comprises a connecting node of a bus beam and a steel pipe herringbone column in a combined framework and a connecting node of an inlet and outlet line beam and the steel pipe herringbone column.

Referring to fig. 3, a beam-column connection structure of a power transformation framework comprises an inlet and outlet beam 1, a bus beam 2 and a steel pipe herringbone column 3, wherein the inlet and outlet beam 1 and the bus beam 2 are fixedly connected with the steel pipe herringbone column 3; the wire inlet and outlet beam 1 and the bus beam 2 both adopt lattice beams with triangular sections; the steel pipe herringbone column annular gusset plate 32 and the overhanging bracket top plate are arranged at the connecting node of the steel pipe herringbone column 3, and the overhanging bracket top plate comprises an overhanging bracket top plate 33 connected with the incoming and outgoing line beam and an overhanging bracket top plate 34 connected with the bus beam; a stiffening plate 36 is arranged below the annular gusset plate of the steel pipe herringbone column, a column top plate 31 is arranged at the top end of the steel pipe herringbone column, a stiffening plate 35 is arranged below the column top plate, the incoming and outgoing line beam 1 is arranged above the bus bar beam 2, and the bus bar beam upper chord 21 and the bus bar beam lower chord 22 are respectively connected with the steel pipe herringbone column 3; the upper chord 11 of the inlet and outlet beam and the lower chord 12 of the inlet and outlet beam are respectively connected with the steel pipe herringbone columns 3.

The bus beam vertical diagonal web members 23 at the bus beam ends are connected with stiffening plates 36 below the steel pipe herringbone column annular node plates, the bus beam horizontal crossed diagonal web members 24 at the bus beam ends are connected to the bus beam lower chord member 22 rod end connecting plates, and the rod end connecting plates of the bus beam lower chord member 22 are connected with the bracket top plate 34 cantilevered on the steel pipe herringbone column.

The vertical diagonal web members 13 of the inlet and outlet line beams at the ends of the inlet and outlet line beams are connected with the stiffening plates 35 below the column top plate, the horizontal crossed diagonal web members 14 of the inlet and outlet line beams at the ends of the inlet and outlet line beams are connected to the rod end connecting plates of the lower chords 12 of the inlet and outlet line beams, and the rod end connecting plates of the lower chords 12 of the inlet and outlet line beams are connected with the bracket top plate 33 cantilevered on the steel pipe herringbone column.

The width of the beam ends of the bus beam 2 and the wire inlet and outlet beam 1 is less than the width of the span of the bus beam 2 and the wire inlet and outlet beam 1.

When the incoming and outgoing line beam 1 and the bus bar beam 2 are connected with the steel pipe herringbone column 3, beam end connecting plates are arranged at the beam ends of the incoming and outgoing line beam 1 and the bus bar beam 2, and are connected with the column top plate 31, the annular node plate 32 or the cantilever bracket top plate through bolts, and circular holes are formed in the beam end connecting plates.

The cantilever bracket on the steel pipe herringbone column needs enough rigidity, and the connection calculation of the cantilever bracket and the herringbone column meets the standard requirement.

The invention relates to a design method of a beam-column connecting structure of a power transformation framework, which comprises the following specific processes:

acquiring boundary conditions, namely acquiring the earthquake motion peak acceleration value of the area where the transformer substation engineering is located, the corresponding earthquake basic intensity, the earthquake motion response spectrum characteristic period and the meteorological conditions of the area where the station site is located;

calculating the load acting on the steel pipe herringbone column combined framework;

and obtaining the member section size of the beam-column connection structure of the power transformation framework by adopting a limit state design method and combining the load and the boundary conditions, thereby obtaining the beam-column connection node and the whole structure of the power transformation framework.

At the connecting nodes of the inlet and outlet line beams and the chord members of the bus beams and the steel pipe herringbone columns, the steel pipe walls of the herringbone columns are subjected to large local stress transmitted by the beam connecting plates, and the conversion stress in a three-dimensional stress state needs to be checked.

The fixed connection nodes in the combined framework comprise two conditions of connection nodes of the bus beam and the steel pipe herringbone column and connection nodes of the incoming and outgoing line beam and the steel pipe herringbone column.

1) And a bus beam and a steel pipe herringbone column in the combined framework are connected. The steel pipe herringbone column 3 is regarded as an integral rigid frame column in the plane and is integrally and fixedly connected with the bus bar beam 2 with a triangular section lattice, crossed steel pipe web members are arranged in the bus bar height range in the plane of the steel pipe herringbone column 3, and through stiffening plates are arranged in the steel pipe column in order to ensure the local stability of the steel pipe column at the joint of the bus bar beam 2 and the steel pipe herringbone column 3. The width of the beam end of the bus beam is narrowed, the height of the beam end of the bus beam is unchanged, a 21-end connecting plate of the upper chord of the bus beam is in bolted connection with a 3-ring-shaped gusset plate 32 of the steel pipe herringbone column, a vertical diagonal web member 23 of the bus beam at the beam end is connected to a stiffening plate 36 below the ring-shaped gusset plate of the steel pipe herringbone column, a bus beam horizontal crossed diagonal web member 24 at the beam end is connected to a 22-end connecting plate of the lower chord of the bus beam, the 22-end connecting plate of the lower chord of the bus beam is in bolted connection with a cantilever corbel top plate 34 connected with the bus beam on the steel pipe herringbone column, and the rigidity of the cantilever corbel directly influences. In order to make the stress of the upper chord 21 and the lower chord 22 of the bus bar beam on the midspan and the support more uniform, a cantilever corbel with enough rigidity is needed and the connection calculation of the cantilever corbel and the herringbone column meets the specification requirement. The steel pipe wall of the steel pipe herringbone column is subjected to large local stress transmitted by the beam connecting plate, and the converted stress in a three-dimensional stress state needs to be checked. Refer to fig. 3a, 3b and 3 c.

2) And the line inlet and outlet beam is connected with the herringbone columns of the steel pipes. The steel pipe herringbone column 3 is seen as an integral double-pipe column outside the plane and is integrally and fixedly connected with the inlet and outlet wire beam 1 with the triangular section lattice. The width of the beam end of the incoming and outgoing line beam is narrowed, the height of the beam end of the incoming and outgoing line beam is unchanged, the beam end connecting plate of the upper chord 11 rod end of the incoming and outgoing line beam is in bolted connection with the column top plate 31, the vertical diagonal web member 13 of the incoming and outgoing line beam at the beam end is connected to the stiffening plate 35 below the column top plate, the horizontal crossed diagonal web member 14 of the incoming and outgoing line beam at the beam end is connected to the rod end connecting plate of the lower chord 12 rod of the incoming and outgoing line beam, the rod end connecting plate of the lower chord 12 rod end of the incoming and outgoing line beam is in bolted connection with the cantilever bracket top plate 33 connected with the incoming and outgoing line beam on the steel pipe herringbone column 3, and the rigidity of the cantilever bracket directly influences the magnitude of the bending moment in the crossing of the incoming and outgoing line beam. In order to enable the stress of the upper chord 11 of the incoming and outgoing line beam and the lower chord 12 of the incoming and outgoing line beam to be more uniform at the midspan and the support, the cantilever corbels with enough rigidity are needed and the connection calculation between the cantilever corbels and the steel pipe herringbone columns 3 meets the specification requirements. At the joint of the lower chord 12 of the incoming and outgoing line beam and the steel pipe herringbone column 3, the steel pipe wall of the steel pipe herringbone column is subjected to large local stress transmitted by the beam connecting plate, and the conversion stress in a three-dimensional stress state needs to be checked. When the incoming and outgoing line beam 1 is fixedly connected with the steel pipe herringbone column 3, only the rod end connecting plate of the upper chord 11 of the incoming and outgoing line beam extends onto the column top plate 31, so that the size of the column top plate and the number of stiffening plates are greatly reduced, and meanwhile, a ground line column or a lightning rod is conveniently connected on the column top plate. The problem that the connecting plate of the rod end of the lower chord of the wire inlet and outlet beam collides with the ground wire column or the lightning rod base when the wire inlet and outlet beam is hinged with the steel pipe herringbone column is solved, and reference is made to fig. 4a, 4b and 4 c.

The structural design that the lattice beam with the triangular cross section in the combined framework is integrally and fixedly connected with the steel pipe herringbone column is pioneered at home and abroad.

The total plane layout of a 750kV framework in a new construction of a certain 750kV transformer substation and the wire tension under each load working condition are combined, space calculation is carried out on an integral model established for the 750kV framework by utilizing space rod system analysis software STAAD Pro (V8i), and calculation comparison is respectively carried out on a fixed joint and a hinged joint of a beam column of a herringbone column combined framework of a steel pipe, so that an optimal node structure type is provided.

The same boundary conditions are input in both structural models: 1) basic wind pressure, 2) earthquake peak acceleration value of the station area, corresponding earthquake basic intensity and earthquake response spectrum characteristic period, 3) other meteorological conditions of the area where the station site is located, and the like.

Calculating load (or action)

The load acting on the steel pipe herringbone column combined framework mainly comprises the following loads: and (3) analyzing and calculating the temporary load, the temperature action and the earthquake action generated by the tension of the lead (ground) wire, the self weight of the structure, the wind load, the ice load, the installation and the maintenance according to the load generated in the final scale.

The wire tension is provided by the electrical profession by which the wire icing load is considered in the wire tension.

The wind load has great influence on a power transformation framework, and the action effect of 0-degree wind and 90-degree wind (namely wind along a conducting wire and wind vertical to the conducting wire) on the framework is considered according to the requirements of the current national standard 'high-rise structure design specification' GB 50135. The basic natural vibration period T of the general structure is more than or equal to 0.25s, the structural vibration caused by wind is obvious, and the wind vibration is enhanced along with the increase of the natural vibration period of the structure, so the influence of the wind vibration is considered during the design. In the specification of overhead transmission line tower structure design technology, DL/T5154, the wind vibration coefficient beta z is a coefficient for the free-standing iron tower when the total height does not exceed 60 m.

For a more flexible frame structure, the effect of wind vibration is generally greater than that of an earthquake, but if the structure is heavier and is located in a high seismic intensity area, the effect of the earthquake is more intense. Therefore, the structure built in the earthquake high-intensity area fully considers the influence of earthquake action to ensure the safety of the structure. The building earthquake-resistant design code GB50011 stipulates that the vertical earthquake action is calculated for the high-rise structure in the area with the intensity of more than 8 degrees. The horizontal and vertical seismic effects are calculated by a reaction spectrum method.

For the framework exposed outdoors, the influence of the temperature effect is direct, the longitudinal dimension of the structure is large, and the accumulative effect of the temperature effect is obvious. The structural design technical regulation of transformer substation DL/T5457 stipulates that the influence of temperature effect should be calculated by arranging continuous bent frames with rigid support total length more than 150m or continuous rigid frames with total length more than 100 m at both ends. When the temperature effect is calculated, the temperature difference is reasonably selected and calculated according to the specific conditions of the engineering.

Load (or effect) combination

The 750kV combined framework is designed by adopting a limit state design method, namely a bearing capacity limit state and a normal use limit state. The load-bearing capacity limit condition corresponds to a deformation of the structure or structural member that reaches a maximum load-bearing capacity or is not suitable for continued load-bearing, and the normal use limit condition corresponds to a condition where the structure or structural member reaches some prescribed limit for normal use or durability.

1) For load-bearing capacity limit conditions, the structure and components should be designed for a basic combination of load effects.

2) For normal use limit conditions, the design is made using a standard combination of loads.

Control conditions of normal use limit state: the allowable deflection value of the column top is h/200(h is the calculated point height of the column) for the plane inside and outside (with end supports) of the herringbone column of the steel tube, and the span of the cross beam is L/400(L is the span of the beam).

Calculation model

The 750kV framework adopts a combined framework, a steel pipe herringbone column and a triangular section lattice beam structure, and an inlet and outlet line beam, a bus beam and the steel pipe herringbone column respectively adopt a calculation model of hinging and fixedly connecting two node types, and refer to the figure 1 and the figure 2 respectively.

Determination of calculated length of steel pipe herringbone column

1) The wire inlet and outlet beam and the bus beam are hinged with the steel pipe herringbone column

Firstly, regarding the steel pipe herringbone column as an integral rigid frame column, hinging the steel pipe herringbone column with a bus beam in a plane, searching according to the calculated length coefficient of the frame column without lateral movement, and obtaining that the linear rigidity of the cross beam is zero, k1 is 0, k2 is 10, and the value under mu 1 is 0.732. The integral slenderness ratio lambda 1 of the lower column is mu 1 and L1 and I1, wherein L1 is 31.5m, and the turning radius of the integral cross section of the connection part of the herringbone column of the steel pipe and the bus beam to the longitudinal axis is deviated from the conservative I1; the upper section of the column is a cantilever column, the length-to-fineness ratio of mu 1 is 2.0, the integral length-to-fineness ratio of lambda 1 is mu 1, L1 is higher/i 1, the L1 is 11.5m, and the turning radius of the integral cross section of the herringbone column head of the steel tube on the conservative i1 is deviated from the turning radius of the longitudinal axis. And secondly, calculating the stability of the column limb in the plane of the herringbone column of the steel pipe, wherein the calculated length coefficient mu 2 is 0.7 and 1.0 from the lower section to the upper section in sequence. The steel pipe herringbone column is hinged with the incoming and outgoing line beam outside the plane, the end part is provided with an end support, the steel pipe herringbone column is firstly regarded as an integral double-column, the calculation length coefficient of the frame column without lateral movement is used for searching, the linear rigidity of the beam is zero, k1 is 0, k2 is 10, and mu 2 is 0.732. The overall length-to-fineness ratio lambda 2 is mu 2L 2/i2, wherein L2 is 43.0m, and i2 is the gyration radius of the overall section of the steel pipe herringbone column to the horizontal axis. And secondly, calculating the stability of the herringbone column limb of the steel pipe outside the plane, wherein the length coefficient mu 3 is 0.5, the L3 is 43.0m, and the i3 is the turning radius of the section of the herringbone column limb of the steel pipe.

2) The incoming and outgoing line beams and the bus beams are connected with the steel pipe herringbone column in a fixed connection mode

Firstly, regarding the steel pipe herringbone column as an integral rigid frame column, fixedly connecting the steel pipe herringbone column with a bus bar beam in a plane, searching according to a calculated length coefficient of the frame column without lateral movement, wherein k1 is the ratio of the sum of the rigidity of a beam line intersected at the upper end of the column to the sum of the rigidity of a column line, multiplying the rigidity of the beam line by 1.5 when the far end of the beam is hinged, and multiplying the rigidity of the beam line by 2.0 when the far end of the beam is embedded, so that the k1 is larger when the beam is fixedly connected with the column, and the calculated length coefficient mu is smaller when the k2 value is constant. The column line rigidity of the lower section deviated from the conservative value is calculated by the inertia moment of the integral cross section of the steel tube herringbone column at the column foot to the longitudinal axis, and the column line rigidity of the upper section is calculated by the inertia moment of the integral cross section of the steel tube herringbone column at the connection part with the bus beam to the longitudinal axis, so that the sum of the column line rigidities is larger, the k1 is smaller, and the searched mu value is larger. Calculating k1 to be 0.03, and when k2 to be 10, finding that the coefficient of the calculated length of the lower column in 1) is smaller than that of the lower column in μ 1 to be 0.728; the calculation of the integral slenderness ratio of the upper section column and the calculation of the stability of the column limb in the plane of the herringbone column of the steel pipe are all the same as 1). The steel pipe herringbone column is fixedly connected with the inlet and outlet line beam outside the plane, the end part is provided with an end support, the steel pipe herringbone column is regarded as an integral double-column, k1 is calculated to be 18.89, when k2 is 10, the integral calculated length coefficient of the frame column without lateral movement is found, mu 2 is found to be 0.549, and the integral calculated length coefficient of the steel pipe herringbone column outside the plane in the step 1) is much smaller. The stability calculation of the herringbone column limb of the steel pipe outside the plane is the same as 1).

The comparison shows that the overall calculated length coefficient of the steel pipe herringbone column fixedly connected with the bus bar in the plane of the steel pipe herringbone column is not obviously reduced compared with the hinge joint, but the overall calculated length coefficient of the steel pipe herringbone column fixedly connected with the incoming and outgoing line beams outside the plane is reduced more compared with the hinge joint. Compared with the integral calculation length coefficient of the herringbone columns of the steel pipes connected in an articulated manner, the beam column fixedly connected connection is reduced whether out of the plane or in the plane, and the corresponding section size of the columns is also reduced.

And calculating the local stability of the steel pipe column limb of the steel pipe herringbone column by referring to a formula of the box-shaped section and a 'steel structure design manual'.

Comparison of calculation results

The section size of the member and the section of the main material are shown in table 1 by calculating the structures of the two node types.

TABLE 1 two node type structural member section size and main material section

The incoming and outgoing line beams are fixedly connected with the steel pipe herringbone columns, the upper and lower sections of the steel pipe herringbone columns are uniformly stressed, and the stress is maximum on column feet when the steel pipe herringbone columns are different from the hinged connection; because each steel pipe herringbone column shares most of longitudinal force of the framework, the longitudinal force shared by the end bracing column is much smaller, and the cross section of the end bracing column is reduced most compared with that of the lower end bracing column, which is different from that of the framework which needs to be borne by the end bracing column in hinged connection. The bus beam and the steel pipe herringbone column are fixedly connected, the whole stress of the steel pipe herringbone column is different from that the stress of a column limb only connected with the bus beam is large and the stress of an opposite column limb is small when the steel pipe herringbone column is hinged, so that the section of the column is correspondingly reduced when the framework beam and the steel pipe herringbone column are fixedly connected.

When the incoming and outgoing line beam and the bus beam are fixedly connected with the steel pipe herringbone column, the stress of the middle of the beam span and the support is uniform, and the stress is the largest in the beam span and the minimum in the support stress in the hinged connection, so that the beam section is correspondingly reduced, and the section of each steel pipe chord member of the triangular lattice beam is correspondingly reduced. Because the beam section is reduced, the beam web rod is changed from the original slenderness ratio structural control into stable control, and the material utilization rate is improved. The statistics of the steel amount of the two node type structures show that the steel amount of the structure adopting the fixed joint type structure is reduced by about 18 percent compared with the structure adopting the hinged joint type structure. The incoming and outgoing line beams or the bus beams are fixedly connected with the steel pipe herringbone columns, and the beam columns can be stressed cooperatively, so that the integrity of the framework structure is improved.

Fixed joint design of steel pipe herringbone column combined framework

The combined framework comprises two conditions of a connecting node of a bus beam and a steel pipe herringbone column in the combined framework and a connecting node of an inlet and outlet line beam and the steel pipe herringbone column.

(1) And a bus beam and a steel pipe herringbone column in the combined framework are connected. The steel pipe herringbone column is regarded as an integral rigid frame column in the plane and is integrally and fixedly connected with the lattice beam with the triangular cross section, cross steel pipe web members are arranged in the height range of a bus bar beam in the plane of the steel pipe herringbone column, and through radial stiffening plates are arranged in the steel pipe column in order to ensure the local stability of the steel pipe column at the joint of the bus bar beam and the steel pipe herringbone column. The width of the beam end of the bus beam is narrowed, the height of the beam end of the bus beam is unchanged, the rod end connecting plate of the upper chord of the bus beam is in bolted connection with the annular node plate of the steel pipe herringbone column, the vertical diagonal web member of the bus beam at the beam end is connected to the stiffening plate below the annular node plate of the steel pipe herringbone column, the horizontal crossed diagonal web member of the bus beam end is connected to the rod end connecting plate of the lower chord, the rod end connecting plate of the lower chord of the bus beam is in bolted connection with the cantilever bracket top plate on the steel pipe herringbone column, the rigidity of the cantilever bracket directly influences the bending moment in the span of the bus beam, the smaller the rigidity of the cantilever bracket is, the larger the bending moment in the span of the bus beam is, the more the synergistic effect of the bus beam and the steel pipe herringbone column is not obvious, and the bus beam is nearly hinged to the steel pipe herringbone column. In order to enable the stress of the upper chord and the lower chord of the bus beam at the midspan and the support to be more uniform, the cantilever corbels with enough rigidity are required, and the connection calculation between the cantilever corbels and the steel pipe herringbone columns meets the specification requirements. At the joint of the bus beam chord member and the steel pipe herringbone column, the steel pipe wall of the steel pipe herringbone column is subjected to large local stress transmitted by the beam connecting plate, and the converted stress in a three-dimensional stress state needs to be checked and calculated. The bus bar beam and the steel pipe herringbone column fixedly connected node are shown in fig. 3a, fig. 3b and fig. 3c, and the number of bolts in the figure is only schematic.

(2) And the line inlet and outlet beam is connected with the herringbone columns of the steel pipes. The steel pipe herringbone column is regarded as an integral double pipe column outside the plane and is integrally and fixedly connected with the lattice beam with the triangular section. The width of the beam end of the line inlet and outlet beam is narrowed, the height of the line inlet and outlet beam is unchanged, the rod end connecting plate of the upper chord of the line inlet and outlet beam is connected with the column top plate through bolts, the vertical diagonal web member of the line inlet and outlet beam at the beam end is connected with the stiffening plate below the column top plate, the horizontal crossed diagonal web member of the line inlet and outlet beam end is connected with the rod end connecting plate of the lower chord of the line inlet and outlet beam, the rod end connecting plate of the lower chord of the line inlet and outlet beam is connected with the cantilever bracket top plate on the steel tube herringbone column through bolts, the rigidity of the cantilever bracket directly influences the bending moment of the line inlet and outlet beam in span, the smaller the rigidity of the cantilever bracket is, the larger the bending moment of the line inlet and outlet beam in span is, the more and less obvious the synergistic effect of the line inlet and outlet beam and the steel tube herringbone column is achieved, and the line inlet and outlet beam is nearly hinged to the steel tube herringbone column. In order to enable the stress of the upper chord and the lower chord of the incoming and outgoing line beam at the midspan and the support seat to be more uniform, the cantilever corbels with enough rigidity are required, and the connection calculation between the cantilever corbels and the steel pipe herringbone columns meets the specification requirements. At the joint of the lower chord of the incoming and outgoing line beam and the steel pipe herringbone column, the steel pipe wall of the steel pipe herringbone column is subjected to larger local stress transmitted by the beam connecting plate, and the converted stress in a three-dimensional stress state needs to be checked and calculated. When the incoming and outgoing line beam is fixedly connected with the steel pipe herringbone column, only the connecting plate at the end of the chord rod on the incoming and outgoing line beam extends onto the column top plate, so that the size of the column top plate and the number of stiffening plates are greatly reduced, and meanwhile, the ground line column or the lightning rod is conveniently connected on the column top plate. The problem that the beam lower chord rod end connecting plate collides with a ground wire column or a lightning rod base when the wire inlet and outlet beam is hinged with the steel pipe herringbone column is solved. The fixed joint of the wire inlet and outlet beam and the steel pipe herringbone column is shown in fig. 4a, 4b and 4c, and the number of bolts in the figure is only schematic.

When the incoming and outgoing line beam and the bus beam are hinged with the steel pipe herringbone column, the beam support adopts an elliptical hole for convenient installation, the hole length direction is along the beam length direction, relative sliding is allowed between the beam end of the framework and the support, the temperature stress of each span is partially released, the state cannot be accurately simulated in the STAAD model, and the calculated temperature stress is larger than the actual stress. When the incoming and outgoing line beam and the bus beam are fixedly connected with the steel pipe herringbone column, in order to transmit the internal force of the beam end of the framework, the beam support seat adopts a circular hole, relative sliding is not allowed between the beam end and the support seat, and the situation that the internal force redistribution is inconsistent with the elastic calculation model is avoided. The STAAD model can accurately simulate the actual temperature stress state of the structure. But the circular holes are adopted, so that higher requirements are provided for the processing precision of the framework beam.

In order to improve the permeability of the whole distribution device area and save steel by adopting the 750kV distribution device area adopting the HGIS arrangement scheme, the framework column adopts a steel pipe herringbone column, the framework beam adopts a lattice beam with a triangular section, and the beam column is fixedly connected, so that the overall calculated length coefficient of the steel pipe herringbone column is reduced, the column section and the beam section are further reduced, and the material utilization rate of the beam web member is improved. The structure adopting the fixed joint type reduces the steel amount by about 18 percent compared with the structure adopting the hinge joint type. And the integrity and the safety reserve of the whole combined framework are effectively improved after the beam column is fixedly connected with the node.

No matter the bus beam or the incoming and outgoing beam or the bus beam, in order to enable the stress of the bus beam or the upper chord and the lower chord of the incoming and outgoing beam to be more uniform in the midspan and at the support, a cantilever bracket with enough rigidity is needed, and the connection calculation between the cantilever bracket and the steel pipe herringbone column meets the specification requirement. At the joint of the upper chord member and the lower chord member of the bus beam and the lower chord member of the inlet and outlet beam and the steel pipe herringbone column, the steel pipe wall of the steel pipe herringbone column is subjected to large local stress transmitted by the beam connecting plate, and the converted stress in a three-dimensional stress state needs to be checked and calculated. When the incoming and outgoing line beam is fixedly connected with the steel pipe herringbone column, only the connecting plate at the end of the chord rod on the incoming and outgoing line beam extends onto the column top plate, so that the size of the column top plate and the number of stiffening plates are greatly reduced, and meanwhile, the ground line column or the lightning rod is conveniently connected on the column top plate.

In order to accurately transmit the internal force of the beam end of the framework, the beam support adopts a circular hole, relative sliding is not allowed between the beam end and the support, and the condition that the internal force redistribution is inconsistent with the elastic calculation model is avoided.