Space multi-limb giant cast steel joint and positioning and mounting process thereof

Abstract

Vertical cross-shaped rib plates are arranged on the inner wall of the cast steel joint, a transverse through-type annular plate is arranged between the cross-shaped rib plates, a round through hole is formed in the through-type annular plate, the bottom ends of the cross-shaped rib plates abut against a support, and the bottom ends of the cross-shaped rib plates abut against the support. A first notch is formed in the top end of the first limb tube, a second notch is formed in the top end of the second limb tube, a third notch is formed in the top end of the third limb tube, a fourth notch is formed in the top end of the fourth limb tube, a first inclined column is inserted into the first notch, and a second inclined column is inserted into the second notch. A third inclined column is inserted into the third notch, and a fourth inclined column is inserted into the fourth notch. The cast steel joint has the advantages of guaranteeing joint integrity, reducing welding deformation, being convenient to install and position, avoiding influence on mechanical properties, improving economic benefits, improving bearing capacity and the like.

Description

Technical Field

[0001] The invention relates to the technical field of positioning and installation of space multi-limb giant cast steel nodes, in particular to space multi-limb giant cast steel nodes and a positioning and installation process thereof. Background Art

[0002] At present, with the development of spatial structures, the span of structures is getting larger and larger, and the forms are also increasing accordingly. Especially in recent years, new structural systems have been constantly emerging, making the connection methods between components in the structure more and more complicated. Traditional node forms such as welded ball nodes and steel pipe intersecting nodes can no longer adapt to the development of modern steel structures. As we all know, the quality of node structure has a considerable impact on the force transmission performance, production and installation, engineering progress and engineering cost of the structure. Therefore, finding a node form with reasonable force, simple construction and low cost has been placed in front of the majority of engineering and technical personnel. With the improvement of casting technology, cast steel nodes have attracted more and more attention from the engineering community for their rationality and practicality. How to integrate cast steel technology into spatial building structures to form nodes with good working performance, reasonable shape, beautiful appearance, and more suitable for on-site construction.

[0003] As a large force-transferring node of a spatial structure, large welded spherical shells were usually used as connecting nodes in previous construction. However, in order to meet the scale of the project and the increasingly complex force requirements of the nodes, as a large force-transferring node, the design requirements can only be met by enlarging the size and specifications of the welded spherical shells. Due to its own process problems and the increasingly complex node requirements of the structural style, the steel binding process and welding technology of the welded ball often cannot achieve the expected results.

[0004] To this end, we have developed a spatial multi-limb giant cast steel node to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a spatial multi-limb giant cast steel node, which has the advantages of ensuring the integrity of the node, reducing welding deformation, facilitating installation and positioning, avoiding affecting mechanical properties, improving economic benefits, and increasing bearing capacity.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a spatial multi-limb giant cast steel node, the cast steel node is a hemispherical shell structure, the spherical surface of the cast steel node is integrally formed with a multi-limb corbel, the multi-limb corbel includes a first limb tube, a second limb tube, a third limb tube and a fourth limb tube uniformly distributed in a clockwise direction, a vertical cross rib plate is provided on the inner wall of the cast steel node, a horizontal through-type ring plate is provided between the cross rib plates, the through-type ring plate is provided with a circular through hole, and the bottom end of the cross rib plate is abutted against the support.

[0007] Preferably, a first slot is provided at the top of the first limb tube, a second slot is provided at the top of the second limb tube, a third slot is provided at the top of the third limb tube, and a fourth slot is provided at the top of the fourth limb tube. The first slot is connected to a first inclined column, the second slot is connected to a second inclined column, the third slot is connected to a third inclined column, and the fourth slot is connected to a fourth inclined column.

[0008] Preferably, ear plates evenly distributed around the circumference are provided on the outer wall of the cast steel node, an ear hole is provided at the middle position of the ear plate, and the ear plates are respectively provided between adjacent positions of the first limb tube, the second limb tube, the third limb tube and the fourth limb tube.

[0009] Preferably, the angle between the center of the ear hole and the center of the cast steel node is α, and the range of the angle α is 20°≤α≤40°.

[0010] Preferably, the wall thickness of the first limb tube is 2.03 to 2.14 times the wall thickness of the first oblique column.

[0011] A positioning and installation process of a spatial multi-limb giant cast steel node includes the following steps: S100. On-site positioning and installation: Preliminarily install the node according to the blueprint coordinates, then set the patch acquisition coordinates at the center of the node bracket, check and adjust by comparing the processing model coordinates, and check again by comparing the node bracket with the center line of the upper oblique column, then fix the node, and finally adjust the angle of the upper oblique column according to the positioning coordinates for upper installation; S200. Use a certain, one-measurement, one-core technical means to control the installation coordinate points: Determine: Carry out plane positioning of cast steel nodes on the blueprint, and use the total station to preliminarily determine the positioning position of the spatial multi-limb giant cast steel node on the sliding anti-seismic support at the bottom of the cast steel node through the two-dimensional coordinate points; First measurement: According to the multi-directional characteristics of the spatial multi-limb giant cast steel node, four control reference points are set. The reference point is the center of the multi-limb tube center circle. The cross center point method is used. The positioning is completed using a prism. The total station laser is used to capture the three-dimensional coordinates of the spatial entity. The casting model spatial position coordinates, workshop production control coordinates and measurement coordinates are checked and measured to ensure the steering angle position of the spatial multi-limb giant cast steel node. The four points are referenced to each other. First core: According to the design characteristics of the inclination angle of the multi-directional double V-shaped inclined column, the center of gravity of the multi-limb giant cast steel node should coincide with the axis. A theodolite is used at the axis position to conduct a secondary check on the relative position of the limb tube and the overall axis to achieve the purpose of secondary verification; S300. After positioning is completed and welded to the lower sliding anti-seismic support, the multi-directional double V-shaped inclined column is hoisted. Due to the precise positioning of the lower part of the inclined column, the lower end of the multi-directional double V-shaped inclined column only needs to be connected with the multi-limb giant cast steel node limb tube to ensure concentricity to achieve the designed angle.

[0012] Preferably, in step S200, during the installation process, the inclination angle of the limb tube needs to be controlled to be at an angle of 66.9° with the parallel axis.

[0013] Preferably, the positioning and installation process includes a precision control method, and the precision control method includes cast steel node processing precision control: processing a three-dimensional model, exporting coordinate digital programming, adjusting the mold casting node, correcting the physical digital model through a three-dimensional scanning, and then measuring with a light pen to complete the node.

[0014] Preferably, the precision control method also includes pre-spatial lofting of the cast steel node through a three-dimensional model in the detailed design stage, presenting the relative position relationship between the limb tube and the support inclination angle of the cast steel node in advance, and the relative spatial position of the inclination angle of the multi-limb corbel and the connected pipe fittings will determine the accuracy of the entire upper system; in the prefabrication of the cast steel factory, first confirm the coordinates of the center point of the limb tube in the three-dimensional model, and then output the three-dimensional model as a two-dimensional production drawing, measure the coordinates of the control point, and then carry out process processing, perform digital programming before process processing, and use the coordinate center of the two-dimensional drawing as control to virtually pre-assemble the engraved model.

[0015] Preferably, the precision control method also includes virtual pre-assembly, positioning and displaying the on-site spatial inclination angle in the factory production stage, specifically casting the casting as a corbel integrated spherical shell casting with an inclination direction, confirming the inclination direction position of the upper docking inclined column in the factory prefabrication three-dimensional model stage, and directly docking the casting with the inclined column after the casting is accurately installed on site; using optical spatial dimension measurement technology to spatially locate and verify the casting, and the specific method is to use photogrammetry and light pen measurement system to verify the size; using a special camera to make a digital image of the measured workpiece, and after image processing, annotation recognition, image space matching, spatial triangulation intersection and beam adjustment, the three-dimensional spatial coordinates of the measured point are obtained. The control point of the multi-directional steel casting is the center point of the corbel tube. The measured data collected is then compared with the center coordinate position of the corbel tube extracted from the casting design software to calculate the geometric error of the workpiece surface. The digital model comparison is fully realized. After the error points and data are identified, the error points are marked on the castings and repaired in time. The processed castings are surveyed again using the light pen measurement system. The light pen measurement system is a contact measurement system that can accurately measure the single-point reference point of the workpiece. The camera measurement system is combined with the light pen measurement system to form a universal coordinate system. The coordinates of the two are unified, and the key points are confirmed and reviewed again to ensure the inclination, direction and size of the castings from a process perspective.

[0016] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: 1. The hemispherical bearing is made of cast steel to avoid the residual stress caused by the 1 / 4 circle butt welding of the traditional welded spherical shell node, ensuring the integrity of the entire node.

[0017] 2. The use of cast steel hollow spherical tubes, that is, the hemispherical support and the upper cast steel bracket are cast together to avoid the large welding stress distribution caused by the direct welding of traditional steel brackets or upper steel columns on the spherical surface, and reduce the node welding deformation.

[0018] 3. The cast steel hollow spherical tube, i.e. the hemispherical support, is cast together with the upper cast steel corbel for the installation of the upper multi-directional double V-shaped column, providing positioning and on-site operability.

[0019] 4. In order to improve the stress distribution of this node, relieve stress concentration and avoid affecting the mechanical properties of the casting, the inner and outer walls of the junction of the cast steel pipe, cast steel bracket and cast steel hemisphere are designed with R=200mm chamfer, which can ensure a smooth transition between the ball and the tube, relieve the deformation state of the component and avoid folding.

[0020] 5. For the hollow cast steel node hemispherical support, a horizontal annular through-type ring plate is set in the middle of the spherical shell in the direction parallel to the ground to ensure that the inside of the spherical shell is a through-type cavity. It can not only reduce the dead weight, but also play the role of a process hole in the manufacturing process. It avoids the decline in economic benefits and the increase in structural weight caused by the excessive weight of the casting.

[0021] 6. In order to strengthen the bearing capacity of the hemispherical bearing, a 150mm thick full-length cross stiffening rib is set in the vertical direction of the ground to tighten the lower contact member to achieve a common force effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the top structure of the spatial multi-limb giant cast steel node of the present invention.

[0023] Figure 2 For the present invention Figure 1 Cross-sectional view at AA in the middle.

[0024] Figure 3 It is a schematic diagram of the bottom structure of the cast steel node of the present invention.

[0025] Figure 4 It is a structural schematic diagram of the top end of the spatial multi-limb giant cast steel node of the present invention, in which a positioning inclined column is inserted.

[0026] Figure 5 The figure is a schematic diagram of the processing accuracy control flow of the spatial multi-limb giant cast steel node of the present invention.

[0027] Figure 6 It is a schematic diagram of the on-site positioning and installation process of the present invention.

[0028] Figure 7 This is the stress-strain relationship curve of the cast steel node material of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] Figures 1 to 6 In the figure, a spatial multi-limb giant cast steel node is provided, the cast steel node 100 is a hemispherical shell structure, the spherical surface of the cast steel node 100 is integrally formed with a multi-limb corbel, the multi-limb corbel comprises a first limb tube 1, a second limb tube 2, a third limb tube 3 and a fourth limb tube 4 which are uniformly distributed in a clockwise direction, a vertical cross rib plate 101 is provided on the inner wall of the cast steel node 100, a horizontal through-type ring plate 102 is provided between the cross rib plates 101, the through-type ring plate 102 is provided with a circular through hole 103, and the bottom end of the cross rib plate 101 is abutted against a support.

[0031] A first slot 11 is provided at the top of the first limb tube 1, a second slot 21 is provided at the top of the second limb tube 2, a third slot 31 is provided at the top of the third limb tube 3, and a fourth slot 41 is provided at the top of the fourth limb tube 4. The first slot 11 is plugged with a first inclined column 201, and a first splint 2011 is provided at the bottom of the first inclined column 201. The second slot 21 is plugged with a second inclined column 202, and a second splint 2021 is provided at the bottom of the second inclined column 202. The third slot 31 is plugged with a third inclined column 203, and a third splint 2031 is provided at the bottom of the third inclined column 203. The fourth slot 41 is plugged with a fourth inclined column 204, and a fourth splint 2041 is provided at the bottom of the fourth inclined column 204. In implementation, double-connected splints and a guy rope are used as temporary fixing measures to reduce deformation of the inclined columns.

[0032] The outer wall of the cast steel node 100 is provided with ear plates 9 evenly distributed around the circumference, an ear hole 91 is provided at the middle position of the ear plate 9, and an ear plate 9 is provided between the first limb tube 1, the second limb tube 2, the third limb tube 3 and the fourth limb tube 4. The internal forces of the four limb tubes are shown in Table 3, the center line of each limb tube is inwardly in the X-axis direction, and the direction of each limb tube end facing the center of the sphere is the Y-axis direction.

[0033] The center of the ear hole 91 and the center of the cast steel node 100 have an angle α, and the range of the angle α is 20°≤α≤40°, preferably 20°, 30° or 40°. The wall thickness of the first limb tube 1 is 2.03 to 2.14 times the wall thickness of the first oblique column 201. The wall thickness of the cast steel pipe fitting of the first limb tube is 110 mm, and the wall thickness of the steel pipe for the butt oblique column is 54 mm. The wall thickness of the cast steel pipe fitting of the second limb tube is 60 mm, and the wall thickness of the steel pipe for the butt oblique column is 28 mm.

[0034] The material of this steel casting is G20Mn5QT (quenched and tempered) cast steel. Its chemical composition and mechanical properties should comply with the requirements of Table 1: Table 1 Chemical composition and mechanical properties of G20Mn5

[0035] After quenching and tempering heat treatment, the mechanical properties of steel castings should meet the requirements of Table 2: Table 2 Chemical composition and mechanical properties of G20Mn5QT

[0036] The material yield criterion is the Von Mises criterion. The material elastic modulus is E = 2.06 × 105 N / mm 2 , tangent modulus is 6100N / mm 2 , Poisson's ratio µ=0.3, G20Mn5QT design strength 235MPa, yield strength 300MPa, after entering the elastic-plastic stage, the isotropic kinematic strengthening constitutive relationship is adopted, and the material stress-strain relationship curve is as follows Figure 7 As shown in the figure, under the load design value, the maximum stress of the steel casting is 92.8MPa. By comparing Abaqus and Ansys, it can be seen that the trends of stress and displacement results are basically consistent, and the difference in stress peak value is small, only 3MPa, less than 5%, which is in line with the principle of finite element calculation.

[0037] When the calculated stress value is within the design value of 235MPa, take Figure 7 The inclined straight line in the middle is the elastic stage; when the stress value exceeds the design value, it is analyzed according to elastic-plasticity, and the ultimate bearing capacity obtained by the load-displacement curve is not less than 3 times the design value. The node is designed to withstand a pressure of about 25,500 KN, and is cast in one piece in the factory into a casting with a diameter of 2,400 mm and a height of 1,400 mm.

[0038] Table 3 Internal forces of the four limb tubes

[0039] The positioning and installation process of the spatial multi-limb giant cast steel node includes the following steps: S100. On-site positioning and installation: Preliminarily install the cast steel node according to the blueprint coordinates, then set the patch collection coordinates at the center of the node bracket, verify and adjust by comparing the processing model coordinates, and conduct a secondary review by comparing the node bracket with the center line of the upper inclined column, then fix the node, and finally adjust the angle of the upper inclined column according to the positioning coordinates for upper installation.

[0040] S200. Use a certain, one-measurement, one-core technical means to control the installation coordinate points: Be sure to: Carry out plane positioning of the cast steel node on the blueprint, and use the total station to preliminarily determine the positioning position of the spatial multi-limb giant cast steel node on the sliding seismic support at the bottom of the cast steel node through the two-dimensional coordinate points.

[0041] First measurement: According to the multi-directional characteristics of the spatial multi-limb giant cast steel node, four control reference points are set. The reference point is the center of the multi-limb tube center circle. The cross center point method is used with a prism to complete the positioning. The total station laser is used to capture the three-dimensional coordinates of the spatial entity. The spatial position coordinates of the casting model, the workshop production control coordinates and the measurement coordinates are checked and measured to ensure the steering inclination position of the spatial multi-limb giant cast steel node. The four control reference points are referenced to each other.

[0042] Core 1: According to the inclination design characteristics of the multi-directional double V-shaped inclined column, the center of gravity of the multi-limb giant cast steel node should coincide with the axis, and the centroid line of the limb tube mouth needs to be at an angle of β with the center of gravity of the casting node, β=66.9°, that is, during the installation process, the inclination angle of the limb tube needs to be controlled to be 66.9° with the parallel axis. A theodolite is used at the axis position to conduct a secondary review of the relative position of the limb tube and the overall axis to achieve the purpose of secondary review.

[0043] S300. After positioning is completed and welded to the lower sliding anti-seismic support, the multi-directional double V-shaped inclined column is hoisted. Due to the precise positioning of the lower part of the inclined column, the lower end of the multi-directional double V-shaped inclined column only needs to be connected with the multi-limb giant cast steel node limb tube to ensure concentricity to achieve the designed angle.

[0044] A positioning and installation process of a spatial multi-limb giant cast steel node includes a precision control method, the precision control method includes: a spherical one-piece multi-limb bracket of a cast steel node 100 with a hemispherical shell structure, the multi-limb bracket includes a first limb tube 1, a second limb tube 2, a third limb tube 3 and a fourth limb tube 4 uniformly distributed in a clockwise direction, and a processing precision control of the cast steel node 100: processing a three-dimensional model, using a special camera to make a digital image of the measured cast steel node 100 through photogrammetry, deriving coordinate digital programming, adjusting the mold casting node, and completing the node through a one-time correction of the three-dimensional scanning entity digital model and then measuring with a light pen.

[0045] The precision control method also includes pre-spatial lofting of the cast steel node through a three-dimensional model in the detailed design stage, presenting the relative position relationship between the limb tube and the support inclination angle of the cast steel node 100 in advance, and the relative spatial position of the inclination angle of the multi-limb corbel and the pipe fittings connected thereto will determine the precision of the entire upper system; in the prefabrication of the cast steel factory, first confirm the coordinates of the center point of the limb tube in the three-dimensional model, and then output the three-dimensional model as a two-dimensional production drawing, measure the coordinates of the control point, and then carry out process processing, and perform digital programming before process processing, and use the coordinate center of the two-dimensional drawing as control to virtually pre-assemble the engraved model.

[0046] Virtual pre-assembly, positioning and displaying the on-site spatial inclination angle in the factory production stage, specifically in the form of casting a corbel with an inclination direction of the integrated spherical shell casting, confirming the inclination direction of the upper docking inclined column in the factory prefabrication of the three-dimensional model stage, and docking the casting directly with the inclined column after precise installation on site. Use optical spatial dimension measurement technology to spatially locate and verify the casting, specifically using photogrammetry and light pen measurement systems for dimension verification; use a special camera to make a digital image of the measured workpiece, and obtain the three-dimensional spatial coordinates of the measured point after image processing, annotation recognition, image space matching, spatial triangulation intersection and beam adjustment. The control point of this spatial giant multi-limb multi-directional steel casting is the center point of the corbel tube, and then compare the collected measured data with the center coordinate position of the corbel tube extracted in the casting design software creo, calculate the geometric error of the workpiece surface, and fully realize digital model comparison. After identifying the error point and data, the error point will be marked on the casting and repaired in time.

[0047] After the castings have been processed, they are measured again using the light pen measurement system. The light pen measurement system is a contact measurement system that can accurately measure the single-point reference point of the workpiece. The camera measurement system is combined with the light pen measurement system to form a universal coordinate system. The coordinates of the two are unified, and the key points are confirmed and reviewed again to ensure the inclination, direction and size of the castings from a process perspective.

[0048] Since the multi-directional double V-shaped inclined column body is designed to be inclined, the steel column will produce a certain degree of deflection and deformation due to its own weight and inclination. Therefore, after completing the docking of the multi-directional double V-shaped inclined column and the spatial multi-limb giant cast steel node, the inclined column can be better controlled through the constraint control of the lower cast steel node and related spatial positioning measures to achieve an ideal installation effect. During the implementation, double connection splints and the pulling of wind ropes were used as temporary fixing measures to reduce the deformation of the inclined column.

[0049] Casting node loading test: (1) Subject to the test conditions, cast steel nodes are subjected to scaled-down tests, and the geometric similarity ratio of the scaled-down nodes is set to 1:2. Cast steel nodes can be subjected to inspection tests or destructive tests according to actual conditions. The test load for inspection tests should not be less than 1.3 times the maximum design value of internal force; the test load for destructive tests should not be less than 2.0 times the maximum design value of internal force.

[0050] (2) In actual structures, nodes are mainly subjected to axial forces and certain bending moments. The test focuses on examining the influence of the axial pressure of each limb tube on the force of the node, and the bending moment is obtained by applying an eccentric moment to the axial direction. Since the cast steel node is subjected to complex forces and bears a large load, it is difficult for a general reaction frame to complete the test. Therefore, for this test, a special self-balancing reaction frame and assembled connectors are designed to achieve loading. Axial pressure is applied to the end of the limb tube by a jack fixed to the crossbeam of the reaction frame, and bending moments in two directions are applied by the eccentricity of the axial force in two directions in the local coordinate system. The base of the hemispherical shell is fixed to the chassis of the reaction frame device, and the node is fixed by a pin to resist the shear force at the bottom of the node.

[0051] (3) This node test is mainly to verify whether the node strength meets the design requirements, examine the stress distribution in the node area, and arrange the strain gauges and strain rosettes. The strain gauges are arranged around the limb tube, the strain rosettes are arranged around the hemispherical shell, and around the intersection of the limb tube and the hemispherical shell.

[0052] (4) The displacement detection points are arranged at the end of each cast steel circular tube limb. An axial displacement meter and two lateral displacement meters are used to measure the displacement of the ends of the cast steel node branches in three directions.

[0053] (5) The loads applied in the test are actively applied by four pressure jacks, two of which are 1000 tons and two of which are 200 tons. Specifically, the 1000-ton jack is applied to the third limb tube 3 and the fourth limb tube 4, and the 200-ton jack is applied to the first limb tube 1 and the second limb tube 2. For the two-tube node, two 200-ton jacks are used to load the first limb tube 1 and the second limb tube 2 respectively.

[0054] (6) In order to verify the safety of the reaction frame used in this test and ensure that the test is carried out safely and smoothly, a geometric model consisting of four parts was established, namely the cast steel node, the reaction frame (with auxiliary connectors), the connecting end pipe and the connecting plate, and the standard module of the large-scale general finite element software ABAQUS was used for analysis. The maximum deformation of the reaction frame is about 8mm, and its strength and stiffness can meet the loading requirements of this test.

[0055] (7) After the test, the specimens were still within the elastic range within 1.3 times the design load, and the maximum stress of the cast steel node was less than the yield strength of the cast steel material. When the specimens were at 2.0 times the design load, the stress of the cast steel ball node was still less than the yield strength of the cast steel material. The cast steel node specimens met the requirements of the specification.

[0056] The above are only specific application examples of the present invention and do not constitute any limitation on the protection scope of the present invention. Any technical solution formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the present invention.

Claims

1. A spatial multi-limb giant cast steel node, characterized in that: The cast steel node (100) is a hemispherical shell structure. The spherical surface of the cast steel node (100) is integrally formed with a multi-limbed corbel. The multi-limbed corbel comprises a first limb tube (1), a second limb tube (2), a third limb tube (3) and a fourth limb tube (4) which are evenly distributed in a clockwise direction. A vertical cross rib plate (101) is provided on the inner wall of the cast steel node (100). A horizontal through-type ring plate (102) is provided between the cross rib plates (101). The through-type ring plate (102) is provided with a circular through hole (103). The bottom end of the cross rib plate (101) is abutted against a support.

2. The spatial multi-limb giant cast steel node according to claim 1 is characterized in that: A first notch (11) is provided at the top end of the first limb tube (1), a second notch (21) is provided at the top end of the second limb tube (2), a third notch (31) is provided at the top end of the third limb tube (3), and a fourth notch (41) is provided at the top end of the fourth limb tube (4); the first notch (11) is plugged into a first inclined column (201), the second notch (21) is plugged into a second inclined column (202), the third notch (31) is plugged into a third inclined column (203), and the fourth notch (41) is plugged into a fourth inclined column (204).

3. The spatial multi-limb giant cast steel node according to claim 2, characterized in that: The outer wall of the cast steel node (100) is provided with ear plates (9) evenly distributed around the circumference, an ear hole (91) is provided at the middle position of the ear plate (9), and the ear plates (9) are each provided between adjacent portions of the first limb tube (1), the second limb tube (2), the third limb tube (3) and the fourth limb tube (4).

4. The spatial multi-limb giant cast steel node according to claim 3 is characterized in that: The included angle between the center of the ear hole (91) and the center of the cast steel node (100) is α, and the range of the included angle α is 20°≤α≤40°.

5. The spatial multi-limb giant cast steel node according to claim 3 is characterized in that: The wall thickness of the first limb tube (1) is 2.03 to 2.14 times the wall thickness of the first oblique column (201).

6. A positioning and installation process of a spatial multi-limb giant cast steel node according to any one of claims 1 to 5, characterized in that: The following steps are involved: S100. On-site positioning and installation: Preliminarily install the node according to the blueprint coordinates, then set the patch acquisition coordinates at the center of the node bracket, check and adjust by comparing the processing model coordinates, and check again by comparing the node bracket with the center line of the upper oblique column, then fix the node, and finally adjust the angle of the upper oblique column according to the positioning coordinates for upper installation; S200. Use a certain, one-measurement, one-core technical means to control the installation coordinate points: Determine: Carry out plane positioning of cast steel nodes on the blueprint, and use the total station to preliminarily determine the positioning position of the spatial multi-limb giant cast steel node on the sliding anti-seismic support at the bottom of the cast steel node through the two-dimensional coordinate points; First measurement: According to the multi-directional characteristics of the spatial multi-limb giant cast steel node, four control reference points are set. The reference point is the center of the multi-limb tube center circle. The cross center point method is used. The positioning is completed using a prism. The total station laser is used to capture the three-dimensional coordinates of the spatial entity. The casting model spatial position coordinates, workshop production control coordinates and measurement coordinates are checked and measured to ensure the steering angle position of the spatial multi-limb giant cast steel node. The four points are referenced to each other. First core: According to the design characteristics of the inclination angle of the multi-directional double V-shaped inclined column, the center of gravity of the multi-limb giant cast steel node should coincide with the axis. A theodolite is used at the axis position to conduct a secondary check on the relative position of the limb tube and the overall axis to achieve the purpose of secondary verification; S300. After positioning is completed and welded to the lower sliding anti-seismic support, the multi-directional double V-shaped inclined column is hoisted. Due to the precise positioning of the lower part of the inclined column, the lower end of the multi-directional double V-shaped inclined column only needs to be connected with the multi-limb giant cast steel node limb tube to ensure concentricity to achieve the designed angle.

7. The positioning and installation process of the spatial multi-limb giant cast steel node according to claim 6 is characterized in that: In step S200, during the installation process, the inclination angle of the limb tube needs to be controlled to be at an angle of 66.9° with the parallel axis.

8. The positioning and installation process of the spatial multi-limb giant cast steel node according to claim 6 is characterized in that: The positioning and installation process includes a precision control method, and the precision control method includes a cast steel node (100) processing precision control: processing a three-dimensional model, exporting coordinate digital programming, adjusting the mold casting node, and performing a one-time correction of the three-dimensional scanning entity digital model, and then measuring the node through a light pen to complete the node.

9. The positioning and installation process of the spatial multi-limb giant cast steel node according to claim 8 is characterized in that: The precision control method also includes pre-spatial lofting of the cast steel node through a three-dimensional model in the detailed design stage, presenting the relative position relationship between the limb tube and the support inclination angle of the cast steel node (100) in advance, and the relative spatial position of the inclination angle of the multi-limb bracket and the pipe fittings plugged therein will determine the precision of the entire upper system; in the prefabrication of the cast steel factory, first confirm the coordinates of the center point of the limb tube in the three-dimensional model, and then output the three-dimensional model as a two-dimensional production drawing, measure the coordinates of the control point, and then carry out process processing. Before process processing, digital programming is carried out, and the engraved model is virtually pre-assembled with the coordinate center of the two-dimensional drawing as the control.

10. The positioning and installation process of the spatial multi-limb giant cast steel node according to claim 8 is characterized in that: The precision control method also includes virtual pre-assembly, which locates and displays the spatial inclination angle on site during the factory production stage. The specific form is to cast the casting as a one-piece spherical shell casting with a corbel with an inclination direction, and confirm the inclination direction of the upper docking inclined column during the factory prefabrication of the three-dimensional model. After the casting is accurately installed on site, it is directly docked with the inclined column; the casting is spatially positioned and verified by optical spatial dimension measurement technology. The specific method is to use photogrammetry and light pen measurement system for dimensional verification; a special camera is used to make a digital image of the measured workpiece, and the three-dimensional spatial coordinates of the measured point are obtained after image processing, annotation recognition, image space matching, spatial triangulation intersection and beam adjustment. The control point of the steel casting is the center point of the corbel tube. The measured data collected is then compared with the coordinate position of the center of the corbel tube extracted from the casting design software to calculate the geometric error of the workpiece surface. The digital model comparison is fully realized. After the error points and data are identified, the error points are marked on the casting and repaired in time. The processed castings are surveyed again using the light pen measurement system. The light pen measurement system is a contact measurement, which can achieve precise measurement of the single-point reference point of the workpiece. The camera measurement system is combined with the light pen measurement system to form a universal coordinate system. The coordinates of the two are unified, and the key points are confirmed and reviewed again to ensure the inclination, direction and size of the casting from a process perspective.

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