A profiled steel plate group nail bearing capacity test device and a use method thereof

Abstract

This invention discloses a test device and method for testing the bearing capacity of profiled steel sheet group nails. The test device includes a top frame and a bottom frame for supporting the profiled steel sheet. A temporary fixing device is provided between the top and bottom frames. Loading equipment connection devices are provided on the upper side of the top frame and the lower side of the bottom frame. A data acquisition device connected to the profiled steel sheet is provided on one side of the top / bottom frame. This invention can effectively prevent the adverse effects on the profiled steel sheet caused by the relative displacement of the frame during the installation of the test device, avoid the additional load generated by direct clamping of the loading end, and improve the accuracy and reliability of the test results. In addition, the test equipment is easy to install, simple to operate, and reusable, which greatly reduces the test cost, improves resource utilization, and has a broad application market and good development prospects.

Description

Technical Field

[0001] This invention relates to the field of building steel structure technology, and more specifically to a test device and method for testing the bearing capacity of profiled steel sheet group nails. Background Technology

[0002] To meet the requirements of integrated steel structure and roof construction, it is generally necessary to conduct group screw shear performance tests on the self-tapping screw connections between the roof profiled steel sheet and the underlying purlins to study the joint's load-bearing capacity, failure mode, and failure definition. However, current research on the group screw connection performance between profiled steel sheets and purlins is relatively scarce, especially lacking specialized testing equipment to support this research. Due to the generally thin thickness of roof profiled steel sheets, slight carelessness during the installation of the testing equipment may cause unnecessary deformation or introduce additional stress to the steel sheet, thus affecting the accuracy of the test results. In addition, the traditional method of directly clamping the sample at the loading end with clamps makes it difficult to ensure that the sample is only subjected to axial tensile force, which also interferes with the reliability and validity of the test data. Therefore, we need to develop or optimize existing testing equipment to overcome these technical difficulties and ensure that the group screw shear performance test can accurately reflect the connection performance under actual working conditions.

[0003] This application is made in this regard. Summary of the Invention

[0004] This invention provides a test device and method for testing the bearing capacity of profiled steel sheet group nails, which has the advantages of simple installation and disassembly, minimal adverse effects on the profiled steel sheet during installation, uniform stress distribution on the test specimen, and reusability of the device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a test device for the bearing capacity of profiled steel sheet group nails, comprising a top frame and a bottom frame for bearing profiled steel sheet, a temporary fixing device provided between the top frame and the bottom frame, a loading device connecting device provided on the upper side of the top frame and the lower side of the bottom frame, and a data acquisition device connected to the profiled steel sheet provided on one side of the top frame / bottom frame.

[0006] Furthermore, both the top frame and the bottom frame are integral U-shaped structures. The top frame includes a top crossbeam and outer vertical frames on both sides, and the bottom frame includes a bottom crossbeam and inner vertical frames on both sides.

[0007] Furthermore, the temporary fixing device includes a limiting strip first disposed between the outer vertical frame and the inner vertical frame. One end of the limiting strip first is installed on the outer vertical frame and can be rotated and tightened for adjustment.

[0008] Furthermore, the temporary fixing device also includes a limiting strip two disposed between the top crossbeam and the inner vertical plate. One end of the limiting strip two is rotatably mounted on the top crossbeam, and the other end is detachably connected to the inner vertical frame.

[0009] Furthermore, limit plate one and limit plate two are installed by tightening and loosening bolts.

[0010] Furthermore, the limiting strip is installed on the front and back of the top frame.

[0011] Furthermore, the second limiting strip is installed on the back of the top frame.

[0012] Furthermore, both the top crossbeam and the bottom crossbeam are provided with scale lines.

[0013] Furthermore, the data acquisition device includes a data acquisition instrument and a self-folding thin plate connected to the test point of the profiled steel sheet. A displacement gauge is connected to the free end of the self-folding thin plate, and the displacement gauge is connected to the data acquisition instrument.

[0014] The method of using the above-mentioned profiled steel sheet group nail bearing capacity testing device mainly includes the following steps:

[0015] 1. Welding the frame: Cut steel sections of appropriate length according to the test requirements and weld them to form the top and bottom frames. Fix multiple limiting steel strips (first type) to the outer vertical frame on the front of the top frame using loose bolts. The initial installation direction of the limiting strips (first type) is parallel to the direction of the outer vertical frame. Similarly, install multiple limiting strips (first type) and multiple limiting strips (second type) on the back of the top frame. Weld loading end connecting plates to the side of the top and bottom crossbeams of the top frame where the profiled steel sheet is to be installed.

[0016] 2. Assemble the steel frame. After assembly, loosen the loosening bolts, rotate the limiting steel strip 1 and the limiting steel strip 2 by 90° and then tighten the fixing loosening bolts to limit the horizontal movement of the bottom steel frame. Install the second loosening bolt on the limiting steel strip 2 and fix the other end of the limiting strip 2 to the top crossbeam to temporarily limit the relative displacement of the top frame and the bottom frame.

[0017] 3. Install the profiled steel sheet. Adjust the installation position of the profiled steel sheet according to the scale line. Install self-tapping screws at the trough of the profiled steel sheet. The line connecting the self-tapping screws should be straight.

[0018] IV. Installation of the test device: Install the test device on the test loading table. The test device and the test loading table are connected by a pin. After installation, remove one of the loosening bolts of the limit plate.

[0019] 5. Set up the data acquisition device, attach a self-folding thin steel plate near the point to be measured, connect the free end of the self-folding thin steel plate to the displacement gauge, and fix the displacement gauge to other fixed equipment in the laboratory with a clamp;

[0020] 6. Preload: Apply a preload not exceeding 5% of the specified strength or expected yield strength to ensure that the specimen is aligned with the clamp and that the specimen is straight.

[0021] VII. Loading test: Load the test device and collect and record the test data using a data acquisition instrument.

[0022] In summary, it has the following beneficial effects:

[0023] (1) The frame of the present invention achieves horizontal stability of the frame structure by using multiple limiting strips fixed with one bolt. At the same time, multiple limiting strips fixed with two bolts are configured on the back of the frame to temporarily fix the frame structure, which effectively prevents the adverse effects of the relative displacement of the frame on the group nail shear test during the test, and ensures the stability and accuracy of the entire installation process. Moreover, the strips do not need to be removed during the test, making the operation simple and the installation efficiency high.

[0024] (2) The present invention uses a pin to connect the test device and the loading device. The test piece can be deflected to achieve uniform force distribution, avoiding the additional load generated by direct clamping and loading in the traditional method, thus improving the accuracy and reliability of the test results.

[0025] (3) The experimental device of the present invention is designed with practicality and convenience in mind, and the installation and disassembly process is simple and quick. In addition, due to its reusability, it greatly reduces the experimental cost, improves the resource utilization rate, and has a broad application market and good development prospects. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the profiled steel sheet group nail bearing capacity testing device of the present invention;

[0027] Figure 2 This is a schematic diagram showing the detailed front structure of the steel frame before the profiled steel sheet is installed according to the present invention.

[0028] Figure 3 This is a schematic diagram showing the detailed structure of the steel frame structure on the back before the profiled steel sheet is installed according to the present invention.

[0029] Figure 4 This is a bottom view of the steel frame structure after the profiled steel sheet of this invention has been installed;

[0030] Figure 5 This is a schematic diagram showing the connection between the clamping device and the testing device of the profiled steel frame structure loading test bench of the present invention.

[0031] Labeling instructions: 1. Top frame; 11. Top crossbeam; 12. Outer vertical frame; 13. Upper scale line; 14. Limiting strip one; 15. Tightening bolt; 2. Bottom frame; 21. Bottom crossbeam; 22. Inner vertical frame; 23. Lower scale line; 24. Limiting strip two; 3. Corrugated steel sheet; 4. Self-tapping screw; 5. Loading equipment connecting device; 51. L-shaped connecting plate; 52. Pin shaft; 6. Data acquisition device; 61. Self-folding thin plate; 62. Displacement gauge; 63. Data acquisition instrument; 7. Test loading table. Detailed Implementation

[0032] The following is in conjunction with the appendix Figures 1 to 5 The present invention provides a more detailed description of the specific implementation method of the bearing capacity test device and the method of using a group of nails for profiled steel sheets.

[0033] like Figure 1 As shown, a test device for the bearing capacity of profiled steel sheet group nails includes a top frame 1, a bottom frame 2, a profiled steel sheet 3, self-tapping screws 4, a loading device connection device 5, and a data acquisition device 6. The frame structure should preferably use high-quality profiles such as square steel, flat steel, channel steel, or H-beams. When using enclosed steel pipe profiles such as square steel or flat steel, sufficient internal space should be ensured to prevent the loosening bolts 15 from being unable to be installed. One end of the profiled steel sheet 3 is fixed to the top frame 1, and the other end is fixed to the bottom frame 2. The profiled steel sheet 3 is connected to the frame structure by self-tapping screws 4. The loading device connection device 5 is installed on the top frame 1 and the bottom frame 2.

[0034] Multiple 1mm thick self-folding thin plates 61 are installed on the profiled steel sheet 3. The size is L20×30mm and the length is 30mm. One end of the self-folding thin plate 61 is fixed to the profiled steel sheet 3 with AB glue, and the other end is pressed against the spring of the displacement gauge 62. The displacement deformation of multiple test points can be measured by collecting the deformation of the displacement gauge 62 through the data acquisition instrument 63.

[0035] like Figure 2 As shown, the top steel frame 1 is welded together from a top crossbeam 11 and two outer vertical frames 12. Multiple 10mm thick limiting strips 14 are fixed to the outer vertical frames 12 using a single tightening bolt 15. The limiting strips 14 can be rotatably fixed by the tightening bolt 15, thus horizontally limiting the bottom steel frame 2. The bottom frame 2 is welded together from a bottom crossbeam 21 and two inner vertical frames 22. The thickness of the top crossbeam 11 and the bottom crossbeam 21 should be consistent with the purlin thickness in actual working conditions.

[0036] The top beam 11 and the bottom beam 21 are respectively provided with upper scale line 13 and lower scale line 23 distributed along the length direction. The scale line 0 is located in the middle of the beam. During the installation of the profiled steel sheet 3, the position can be adjusted according to the scale line to ensure that the profiled steel sheet 3 is straight and centered.

[0037] like Figure 3 As shown, multiple limiting strips 24 are installed on the back of the bottom frame 2. The limiting strips 24 are made of 10mm thick rectangular steel strips. The top frame 1 and the bottom frame 2 are temporarily connected and fixed by two loose bolts 15. After the test device is installed on the loading device, one of the loose bolts 15 of the limiting steel strips 24 is removed to release the temporary fixation of the two frames and only perform horizontal limiting.

[0038] like Figure 4 As shown, loading device connecting device 5 is installed on the top crossbeam 11 and the bottom crossbeam 21. The loading device connecting device 5 includes a loading end connecting plate 51 and a pin 52. The loading end connecting plate 51 can be made of 10mm thick L-shaped steel plate, rectangular steel plate, T-shaped steel plate, etc., and is welded to the side of the frame or attached to the top / top edge to ensure that the pin hole position and the self-tapping screw hole position are coplanar.

[0039] like Figure 5 As shown, the test device is connected to the loading device via a pin 52. Both ends of the test device can deflect around the pin, and the force can be evenly distributed through the deflection.

[0040] A method for using a test device for the bearing capacity of profiled steel sheet group nails includes the following steps:

[0041] 1. Welding the frame: Cut steel sections of appropriate length according to the test requirements and weld them to form the top frame 1 and the bottom frame 2. Use bolts 15 to fix multiple limiting strips 14 to the outer vertical frame 12 on the front of the top frame. The initial installation direction of the limiting strips 14 is parallel to the direction of the outer vertical frame 12. Similarly, install multiple limiting strips 14 and multiple limiting strips 24 on the back of the frame. Weld loading end connecting plates 51 to the side of the top beam 11 and bottom beam 21 of the frame where the profiled steel sheet 3 is to be installed.

[0042] 2. Assemble the frame. After assembly, loosen the tension bolt 15, rotate the limiting strip 14 and the limiting strip 24 by 90°, and then tighten the tension bolt 15 to limit the horizontal movement of the bottom frame 2. Install a second tension bolt 15 on the limiting strip 24 and fix the other end of the limiting strip 24 to the top crossbeam 11 to temporarily limit the relative displacement of the top frame 1 and the bottom frame 2.

[0043] 3. Install the profiled steel sheet 3. Adjust the installation position of the profiled steel sheet 3 according to the scale line 12. Install the self-tapping screws 4 at the trough of the profiled steel sheet 3. The line connecting the self-tapping screws should be straight.

[0044] IV. Installation of the test device: Install the test device on the test loading table 7. The test device and the test loading table 7 are connected by a pin 52. After installation, remove one of the loosening bolts 15 of the limit plate 24.

[0045] 5. Set up the data acquisition device 6, attach the self-folding thin plate 61 near the point to be measured, connect the free end of the self-folding thin plate 61 to the displacement meter 62, and fix the displacement meter 62 to other fixed equipment in the laboratory by clamps.

[0046] 6. Preload: Apply a preload not exceeding 5% of the specified strength or expected yield strength to ensure that the specimen is aligned with the clamp and that the specimen is straight.

[0047] VII. Loading test: Load the test device and collect and record the test data through the data acquisition instrument 63.

[0048] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A test device for the bearing capacity of profiled steel sheet group nails, characterized in that: It includes a top frame and a bottom frame for supporting the profiled steel sheet. A temporary fixing device is provided between the top frame and the bottom frame. Loading equipment connection devices are provided on the upper side of the top frame and the lower side of the bottom frame. A data acquisition device connected to the profiled steel sheet is provided on one side of the top frame / bottom frame. Both the top frame and the bottom frame are integral U-shaped structures. The top frame includes a top crossbeam and two outer vertical frames on both sides, and the bottom frame includes a bottom crossbeam and two inner vertical frames on both sides. Both the top crossbeam and the bottom crossbeam are provided with scale lines; Weld the loading end connection on the side where the profiled steel sheet is to be installed on the top and bottom crossbeams of the top frame; The loading device connection device includes a loading end connecting plate and a pin.

2. The test device for bearing capacity of profiled steel sheet group nails according to claim 1, characterized in that: The temporary fixing device includes a limiting strip set between the outer vertical frame and the inner vertical frame. One end of the limiting strip is installed on the outer vertical frame and can be rotated and tightened.

3. The test device for bearing capacity of profiled steel sheet group nails according to claim 2, characterized in that: The temporary fixing device also includes a limiting strip two disposed between the top crossbeam and the inner vertical plate. One end of the limiting strip two is rotatably mounted on the top crossbeam, and the other end is detachably connected to the inner vertical frame.

4. The test device for bearing capacity of profiled steel sheet group nails according to claim 3, characterized in that: Limiting strip one and limiting strip two are installed by tightening and loosening bolts.

5. The test device for bearing capacity of profiled steel sheet group nails according to claim 2, characterized in that: The limiting strip is installed on the front and back of the top frame.

6. The test device for bearing capacity of profiled steel sheet group nails according to claim 3, characterized in that: Limiting strip 2 is installed on the back of the top frame.

7. The test device for bearing capacity of profiled steel sheet group nails according to claim 1, characterized in that: The data acquisition device includes a data acquisition instrument and a self-folding thin plate connected to the test point of the profiled steel sheet. A displacement meter is connected to the free end of the self-folding thin plate, and the displacement meter is connected to the data acquisition instrument.

8. The method of using the profiled steel sheet group nail bearing capacity testing device according to any one of claims 1-7, characterized in that, The main steps include:

1. Welding the frame: Cut steel sections of appropriate length according to the test requirements and weld them to form the top frame and bottom frame. Fix multiple limiting steel strips to the outer vertical frame on the front of the top frame with loose bolts. The initial installation direction of the limiting strips is parallel to the direction of the outer vertical frame. Similarly, install multiple limiting strips 1 and multiple limiting strips 2 on the back of the top frame.

2. Assemble the steel frame. After assembly, loosen the loosening bolts, rotate the limiting steel strip 1 and the limiting steel strip 2 by 90° and then tighten the fixing loosening bolts to limit the horizontal movement of the bottom steel frame. Install the second loosening bolt on the limiting steel strip 2 and fix the other end of the limiting strip 2 to the top crossbeam to temporarily limit the relative displacement of the top frame and the bottom frame.

3. Install the profiled steel sheet. Adjust the installation position of the profiled steel sheet according to the scale line. Install self-tapping screws at the trough of the profiled steel sheet. The line connecting the self-tapping screws should be straight. IV. Installation of the test device: Install the test device on the test loading table. The test device and the test loading table are connected by a pin. After installation, remove one of the loosening bolts of the limit plate.

5. Set up the data acquisition device, attach a self-folding thin steel plate near the point to be measured, connect the free end of the self-folding thin steel plate to the displacement gauge, and fix the displacement gauge to other fixed equipment in the laboratory with a clamp; 6. Preload: Apply a preload not exceeding 5% of the specified strength or expected yield strength to ensure that the specimen is aligned with the clamp and that the specimen is straight. VII. Loading test: Load the test device and collect and record the test data using a data acquisition instrument.

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