Testing device for stable bearing capacity of angle steel main material of butt joint node of power transmission tower

Abstract

The utility model belongs to the technical field of bearing capacity tests, and particularly relates to a power transmission tower butt joint node angle steel main material stable bearing capacity test device which comprises a base and a supporting frame, a jack support is fixedly installed at the top of the base, a jack is installed at the top of the jack support, and the output end of the jack is connected with a lower knife edge hinge. The top of the lower knife edge hinge is connected with lower angle steel, the top end of the lower angle steel is connected with upper angle steel, the top end of the upper angle steel is connected with an upper knife edge hinge, and the surface of the supporting frame is provided with an upper inclined material supporting frame and a lower inclined material supporting frame. The side faces of the upper inclined material supporting frame and the lower inclined material supporting frame are connected with an upper inclined material and a lower inclined material respectively. According to the power transmission tower butt joint node angle steel main material stability bearing capacity test device, the mechanical construction level of an angle steel tower can be greatly improved by adopting seat plate type butt joint, and meanwhile, optimization of a main material connection node structure has important significance on reduction of tower weight and engineering investment.

Description

Technical Field

[0001] The utility model relates to the technical field of bearing capacity testing, in particular to a device for testing the stable bearing capacity of a main material of an angle steel at a butt joint of a transmission tower. Background Art

[0002] Angle steel towers are widely used in power transmission lines across the country due to their simple production process, low raw material costs, and high installation efficiency. Existing, common angle steel towers use disconnecting nodes for their main material connections. The diagonal joints between the upper and lower sections are staggered, and the tower body has a large number of disconnecting nodes. A 500kV single-circuit straight tower (60m high) requires approximately 20 to 28 disconnecting nodes, while double-circuit and UHV towers require even more. This makes it impossible to assemble the entire tower, resulting in relatively low mechanized construction efficiency. However, the use of seat-plate docking significantly improves the mechanized construction of angle steel towers. Furthermore, it optimizes the main material connection node structure, which is crucial for reducing tower weight and project investment.

[0003] In a fully assembled angle steel tower system, the main materials inevitably have disconnected nodes throughout the entire tower height. This occurs when two angle steels of the same specification are butted together, connected using single or double wrapped angle steel bolts, or through butt joints. This experimental study focuses on the latter, investigating the instability of the main materials under butt joints. The main materials connected through butt joints are subject to complex forces, and their load-bearing capacity directly affects the stability of the transmission tower. However, my country's "Steel Structure Design Standard" (GB50017-2017) and the power design specification "Technical Specifications for the Structural Design of Overhead Transmission Line Towers" (DL / T 5154-2020) do not consider the impact of the main material base plate butt joint when calculating the main material's stable load-bearing capacity. Utility Model Content

[0004] The purpose of the utility model is to provide a device for testing the stable bearing capacity of the main material of the angle steel of the butt joint of the transmission tower, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a test device for the stable bearing capacity of the main material of the angle steel of the docking node of a transmission tower, comprising a base and a support frame, a jack support is fixedly installed on the top of the base, a jack is installed on the top of the jack support, the output end of the jack is connected to a lower knife-edge twister, the top of the lower knife-edge twister is connected to a lower angle steel, the top of the lower angle steel is connected to an upper angle steel, the top of the upper angle steel is connected to an upper knife-edge twister, an upper oblique material support frame and a lower oblique material support frame are installed on the surface of the support frame, and the sides of the upper oblique material support frame and the lower oblique material support frame are respectively connected to an upper oblique material and a lower oblique material.

[0006] Preferably, the top of the outer surface of the lower angle steel is fixedly connected with a saddle plate three, the top of the lower angle steel is installed with a bottom plate, the top of the bottom plate is fixedly connected with a saddle plate one, and the bottom of the outer surface of the upper angle steel is fixedly connected with a saddle plate two.

[0007] Preferably, the bottom of the lower angle steel is fixedly connected to a connecting plate, the bottom of the connecting plate is fixedly connected to a knife-edge plate, and the bottom of the knife-edge plate is connected to a knife groove plate.

[0008] Preferably, the upper and lower diagonal materials are both supported out of plane by adjacent planar cross diagonal materials or auxiliary materials. Four supporting angle steels perpendicular to the axis of the main diagonal materials are selected as out of plane supports. The supports are made of L50*4 model Q355 hot-rolled equal-leg angle steel with a length of 1000mm.

[0009] Preferably, the jack is 500t and a bidirectional hydraulic jack and an electric oil pump are selected as loading devices, and a 150t force sensor is installed on the cylinder head of the jack.

[0010] Preferably, the upper angle steel and the saddle plate are connected by a 6.8-grade φ16 bolt. The end break node connection is connected by a 6.8-grade φ20 bolt. Four supports are installed on the box beam columns on both sides, and the support ends are connected to the supports with 6.8-grade φ20 bolts.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] The transmission tower docking node angle steel main material stable bearing capacity test device adopts seat plate docking to greatly improve the mechanized construction level of angle steel tower. At the same time, optimizing the main material connection node structure is of great significance for reducing tower weight and project investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the overall structure of the test device of the present utility model;

[0014] Figure 2 This is a schematic diagram of the angle steel structure of the present utility model;

[0015] Figure 3 This is a schematic diagram of the knife-edge twisting structure of the present utility model;

[0016] Figure 4 This is a schematic diagram of the oblique material structure of the present utility model.

[0017] In the figure: 1. Base; 2. Jack support; 3. Lower blade twist; 4. Upper blade twist; 5. Support frame; 6. Upper diagonal material support frame; 7. Upper diagonal material; 8. Lower diagonal material support frame; 9. Lower diagonal material; 10. Upper angle steel; 101. Bottom plate; 102. Saddle plate one; 103. Saddle plate two; 11. Lower angle steel; 1101. Saddle plate three; 1102. Connecting plate; 1103. Blade plate; 1104. Slot plate. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figures 1-4 , the utility model provides a technical solution:

[0020] A device for testing the stable bearing capacity of the main material of the angle steel at the docking node of a transmission tower comprises a base 1 and a support frame 5. A jack support 2 is fixedly installed on the top of the base 1, a jack is installed on the top of the jack support 2, the output end of the jack is connected to a lower knife-edge twister 3, the top of the lower knife-edge twister 3 is connected to a lower angle steel 11, the top of the lower angle steel 11 is connected to an upper angle steel 10, and the top of the upper angle steel 10 is connected to an upper knife-edge twister 4. An upper oblique material support frame 6 and a lower oblique material support frame 8 are installed on the surface of the support frame 5, and the sides of the upper oblique material support frame 6 and the lower oblique material support frame 8 are respectively connected to an upper oblique material 7 and a lower oblique material 9.

[0021] The top of the outer surface of the lower angle steel 11 is fixedly connected with a saddle plate three 1101, the top of the lower angle steel 11 is installed with a bottom plate 101, the top of the bottom plate 101 is fixedly connected with a saddle plate one 102, and the bottom of the outer surface of the upper angle steel 10 is fixedly connected with a saddle plate two 103.

[0022] The bottom of the lower angle steel 11 is fixedly connected to a connecting plate 1102 , the bottom of the connecting plate 1102 is fixedly connected to a knife-edge plate 1103 , and the bottom of the knife-edge plate 1103 is connected to a knife groove plate 1104 .

[0023] Based on typical design data from the State Grid, a standard transmission tower span was selected as the research object. Considering that transmission towers are spatial structures, the main diagonal members are subject to out-of-plane support from the cross diagonals or auxiliary members connected to them, and the angle between them is not constant. To better simulate the spatial structure of the transmission tower span, both the upper diagonal member 7 and the lower diagonal member 9 are subject to out-of-plane support from the adjacent planar cross diagonals or auxiliary members. Four support angles perpendicular to the axis of the main diagonal members were selected as out-of-plane supports. The supports were L50*4 Q355 hot-rolled equal-leg angles, with a length of 1000mm.

[0024] The test was conducted in an upright position, with a high-rigidity box beam connected end to end to form a balance frame. The specimen was secured within the balance frame to create a self-balancing system. A 500t jack, a bidirectional hydraulic jack and an electric oil pump, were used as the loading device, and a 150t load cell was installed on the jack's cylinder head.

[0025] A 6.8-grade φ16 bolt was used to connect the main diagonal member to the support. The end-break node connection was connected with a 6.8-grade φ20 bolt. Four supports were installed on the box beam columns on both sides of the test. The support ends were connected to the supports with 6.8-grade φ20 bolts. Strip-shaped screw holes were cut in the supports, and the bolts were loosened during installation to allow sufficient movement in the loading direction. Furthermore, each end of the specimen was extended by 2 / 3 of the span length to eliminate the influence of stress concentration on the supports and better simulate spatial stress conditions.

[0026] The ends of the specimens are connected to the balance frame through knife-edge hinges. One reason is to ensure that the main material is subjected to axial force, and the other is that when under pressure, the ends of the specimens can rotate within the minimum axial plane, which better simulates the stress form of the main material in actual engineering.

[0027] Considering that the main material in the spatial internode is supported out of the plane by the planar cross-slant materials, in order to fully consider the authenticity and effectiveness of the simulated boundary conditions during the test, a two-plane three-dimensional internode test method is adopted. Two standard plane internodes are assembled into a three-column three-dimensional internode, and the middle main material is the test material, so as to fully consider the supporting effect of the adjacent diagonal materials on the test main material. The influence of a single parameter on the test object is examined through the test method of controlling variables. The specific parameter settings are shown in the following table.

[0028] Test parameter and working condition setting table

[0029]

[0030] During installation, the specimen was geometrically aligned using a laser level to ensure vertical alignment. A preload was applied before formal loading, with the load level set at 10% of the theoretical stable bearing capacity calculated according to the "Technical Specifications for the Structural Design of Overhead Transmission Line Towers" (DL / T5154-2012). This preload functioned to verify the proper functioning of the test instrumentation and, to a certain extent, to eliminate any gaps between the loading device and the specimen. The formal loading process employed a monotonic, graded loading system, with controlled load increments and loading rates at each stage. Once the specified load was reached, the load was held for 10 seconds. When the load decreased and continued loading failed to increase the pressure sensor reading, the specimen was considered to have reached its stable bearing capacity. Loading was continued until the pressure sensor reading dropped below 85% of the stable bearing capacity, and loading was terminated. To prevent separation of the specimen from the loading device, unloading was stopped at a residual load of 20 kN.

[0031] Working principle:

[0032] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

Claims

1. A transmission tower docking node angle steel main material stability bearing capacity test device, comprising a base (1) and a support frame (5), characterized in that: A jack support (2) is fixedly installed on the top of the base (1), a jack is installed on the top of the jack support (2), an output end of the jack is connected to a lower blade twister (3), a top of the lower blade twister (3) is connected to a lower angle steel (11), a top end of the lower angle steel (11) is connected to an upper angle steel (10), a top end of the upper angle steel (10) is connected to an upper blade twister (4), an upper oblique material support frame (6) and a lower oblique material support frame (8) are installed on the surface of the support frame (5), and the sides of the upper oblique material support frame (6) and the lower oblique material support frame (8) are respectively connected to an upper oblique material (7) and a lower oblique material (9).

2. The device for testing the stable bearing capacity of the main material of the angle steel of the transmission tower docking node according to claim 1 is characterized by: The top of the outer surface of the lower angle steel (11) is fixedly connected to a saddle plate three (1101), the top of the lower angle steel (11) is installed with a bottom plate (101), the top of the bottom plate (101) is fixedly connected to a saddle plate one (102), and the bottom of the outer surface of the upper angle steel (10) is fixedly connected to a saddle plate two (103).

3. The device for testing the stable bearing capacity of the main material of the angle steel of the transmission tower docking node according to claim 1 is characterized in that: The bottom of the lower angle steel (11) is fixedly connected to a connecting plate (1102), the bottom of the connecting plate (1102) is fixedly connected to a knife-edge plate (1103), and the bottom of the knife-edge plate (1103) is connected to a knife groove plate (1104).

4. The device for testing the stable bearing capacity of the main material of the angle steel of the transmission tower docking node according to claim 1 is characterized by: The upper diagonal material (7) and the lower diagonal material (9) are both supported out of plane by adjacent planar cross diagonal materials or auxiliary materials. Four supporting angle steels perpendicular to the axis of the main diagonal material are selected as out of plane supports. The supports are made of L50*4 Q355 hot-rolled equal-leg angle steel with a length of 1000 mm.

5. The device for testing the stable bearing capacity of the main material of the angle steel of the transmission tower joint according to claim 1 is characterized in that: The jack is 500t and a bidirectional hydraulic jack and an electric oil pump are selected as loading devices, and a 150t force sensor is installed on the cylinder head of the jack.

6. The device for testing the stable bearing capacity of the main material of the angle steel of the transmission tower docking node according to claim 1 is characterized by: The upper angle steel (10) and the saddle plate (102) are connected by a 6.8-grade φ16 bolt, and the end break node connection is connected by a 6.8-grade φ20 bolt. Four supports are installed on the box beam columns on both sides, and the support ends are connected to the supports with 6.8-grade φ20 bolts.

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