Opposite-pulling experiment device and method for testing strength of deck crane

Abstract

The invention discloses an opposite-pulling experiment device for testing the strength of a deck crane, which comprises a pair of deck cranes and a locking mechanism, and is characterized in that each deck crane comprises a first cross beam, a second cross beam, a first oblique beam, a second oblique beam and a vertical beam which are connected with one another; the ends of the vertical beams are fixedly connected with the ends of the first cross beam and the second cross beam respectively. The ends of the first oblique beams are connected with the first cross beam and the second cross beam respectively. The end of the second oblique beam is connected with the first cross beam and the vertical beam; a supporting beam is arranged between the second cross beam and the second oblique beam to provide supporting force. A mounting seat, a hydraulic jack and a first electric push rod which are fixed through bolts are arranged at the end part of the second cross beam, a top shaft of the first electric push rod is connected with the mounting seat, the hydraulic jack is fixed on the mounting seat, and a steel strand is arranged on the hydraulic jack for lifting action. According to the method, the bridge deck cranes are symmetrically arranged, the mutual opposite pulling mode is matched with the method for improving load testing in a grading mode, the experiment of the strength of the bridge deck cranes can be achieved, and construction safety and stability are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a pulling test device and a method for testing the strength of a bridge deck crane. Background Art

[0002] The hoisting of steel box girders across waterways is a complex engineering and technical activity that often occurs in bridge construction. It involves hoisting large steel box girder structures from transport vehicles to predetermined locations across rivers, straits, or other waterways. Due to the particularity of waterways, it is required that steel box girders weighing hundreds of tons be accurately installed without affecting the normal operation of the waterway or minimizing the impact on the normal operation of the waterway. Therefore, extremely high requirements are placed on construction plans, safety measures, and technical precision. It is necessary to comprehensively consider factors such as the width, water depth, navigation density, meteorological conditions, and the size and weight of the girder to formulate a scientific and reasonable hoisting plan to achieve safe and stable hoisting, and avoid safety accidents during construction due to insufficient crane lifting force or unreasonable crane structure. Furthermore, during the bridge hoisting process, sufficient lifting force must be provided to ensure stable and safe hoisting of the bridge, bridge deck, and steel box girder. Therefore, before construction, reasonable experiments and tests must be carried out on the lifting force of the bridge crane and the stability of the structure to ensure the normal progress of construction.

[0003] The Beijing-Hangzhou Grand Canal is a national secondary waterway and an important waterway connecting the north and the south, carrying heavy shipping tasks.

[0004] Our company undertook the project "Kaifa Road East Extension Expressway Reconstruction Project, Section 1, Main Bridge Section Across the Beijing-Hangzhou Grand Canal". We conducted research on the difficulties in lifting steel box girders in the construction of bridges across the Beijing-Hangzhou Grand Canal and found that the main problems are concentrated in the following aspects: First, the no-navigation time for construction here must not exceed 4 hours, so it is necessary to complete the lifting, welding, ring peak welding, and stacking plate welding of the bridge within a limited time, which is extremely challenging; if it cannot be completed beyond the scheduled period, it will cause a series of uncontrollable consequences; second, the floating crane is too large to pass through the lock to reach the scheduled construction site smoothly; therefore, to address the above problems, our company has developed a new bridge deck lifting plan; to ensure safe use, it needs to be subjected to strength tension tests before construction; for the experimental plan, our company also referenced reasonable plans in existing technologies;

[0005] For example, the prior art discovered after searching is a bridge steel strand tensile strength test device with publication number CN116952723A, which provides a device for testing the strength of steel strands; however, it still lacks an experimental test method suitable for the strength of the bridge crane body in this solution;

[0006] Therefore, in order to monitor the strength of a bridge crane, the present invention provides a test method for the strength of a bridge crane. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a pulling test device and method for testing the strength of a bridge crane. By symmetrically arranging the bridge cranes and pulling each other in combination with a graded load test method, the strength of the bridge crane itself can be experimentally tested to ensure the safety and stability of the construction.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A pulling test device for testing the strength of a bridge crane comprises a pair of bridge cranes and a locking mechanism, the bridge crane comprising a first crossbeam, a second crossbeam, a first oblique beam, a second oblique beam and a vertical beam which are connected to each other; the ends of the vertical beam are fixedly connected to the ends of the first crossbeam and the second crossbeam respectively, the ends of the first oblique beam are connected to the first crossbeam and the second crossbeam respectively; the ends of the second oblique beam are connected to the first crossbeam and the second crossbeam; a support beam is provided between the second crossbeam and the second oblique beam to provide supporting force; the end of the second crossbeam is provided with a mounting seat fixed by bolts, a hydraulic jack and a first electric push rod, the top shaft of the first electric push rod is connected to the mounting seat, the hydraulic jack is fixed on the mounting seat, and a steel wire rope is provided on the hydraulic jack for lifting action; further, a rib plate is provided between the first crossbeam and the first oblique beam to provide support.

[0010] The first beam includes a pair of fixedly connected third arms; the second beam includes a pair of fixedly connected second arms, a connecting block is provided on the second arm, the connecting block is fixedly connected to the second arm, and the second arms are fixedly connected by the connecting block; the second arm is provided with a sleeved fixing frame, the fixing frame is provided with a top plate, and the top plate is provided in the gap between the second arms; a second electric push rod fixed on the connecting block is provided between the second arms, and the top shaft of the second electric push rod is fixedly connected to the top plate after passing through the connecting block; a limit block is provided on the mounting seat, and the limit block is provided in the gap between the second arms, and the limit block is slidably connected to the second beam to limit the sliding trajectory of the mounting seat; the steel strand is provided in the gap between the second arms; after the bolts of the mounting seat are released, the mounting seat can be pushed by the second electric push rod and the hydraulic jack can be moved on the second beam to change the mutually pulling force positions, thereby testing the influence of different force points on the bridge crane structure.

[0011] The locking mechanism includes a locking plate and an insertion shaft. The locking plate is provided with a slot and a through hole. The slot is provided with a symmetrically distributed push plate. The push plate is provided with a rotatably connected screw. The screw is threadedly connected to the side of the locking plate. The push plate is pushed to move in the slot by rotating the screw.

[0012] The vertical beam includes a pair of fixedly connected first arms, a first fixing block is provided at one end of the first arm, a second fixing block is provided at one side of the first arm, and the second fixing blocks are fixedly connected to each other so that the first arms are connected and fixed as a whole.

[0013] Furthermore, a sleeved square sleeve is provided on the first arm to assist in fixing the first arm and improve the firmness of the connection. The square sleeve is fixed to the first arm by bolts, and a connecting fixing ear plate is provided on the square sleeve at one end of the first arm.

[0014] The second oblique beam includes a first fork arm and a second fork arm that are plugged into each other; the second fork arm includes a mounting block and a first plug plate fixed to the mounting block; the first fork arm is provided with a pair of first slots, and a first spacer is provided between the first slots to ensure support strength; one end of the first fork arm is hingedly connected to the fixing frame, and one end of the second fork arm is hingedly connected to the fixing ear plate; the first plug plate is plugged into the first slot and then a bolt is passed through the first fork arm, the second fork arm, the first plug plate, and then fixed with a nut.

[0015] Furthermore, a fixed third electric push rod is provided on the first fork arm, and one end of the top shaft of the third electric push rod is fixedly connected to the mounting block, and the length of the second oblique beam is adjusted by pushing the mounting block.

[0016] The support beam includes a third fork arm and a fourth fork arm; a second through slot is provided on the third fork arm, and a second partition plate is provided between the second slots to increase the supporting strength; the fourth fork arm is provided at both ends of the third fork arm and is hingedly connected to the second cross beam and the second oblique beam respectively; one end of the fourth fork arm is inserted into the second slot and then a bolt is passed through the third fork arm and the fourth fork arm and then fixed with a nut.

[0017] During the above installation process, when the first electric push rod pushes the mounting seat and the hydraulic jack to move, the bolt locks of the first fork arm, the second fork arm, and the bolt locks of the third fork arm and the fourth fork arm are released, and then the fixed frame can be driven by the push of the second electric push rod to move along the second cross beam, thereby changing the length of the support beam and the second oblique beam, and then locking them with bolts to continue to provide support effects; the third electric push rod can also provide auxiliary power to adjust the length of the second oblique beam, and close cooperation with the second electric push rod is required during this period.

[0018] Preferably, a mounting seat is provided at the end of the first crossbeam, and the symmetrically arranged end of the first crossbeam is fixed by threaded steel bars interspersed with the mounting seat to simulate the stress position of the bridge crane anchoring the bridge deck.

[0019] A tensile test method for testing the strength of a bridge crane is described as follows:

[0020] S1: Equipment inspection:

[0021] 1) Crane body: Check the structural welds, bolt connections, and pin wear:

[0022] 2) Hydraulic system: confirm that the hydraulic jack has no leakage and the pressure gauge has passed the calibration;

[0023] 3) Site layout: symmetrical spacing of bridge cranes; placement of steel columns that provide load-bearing functions;

[0024] S2: Equipment assembly:

[0025] First, assemble the two bridge cranes. Place them flat on a wide, flat, hardened surface, support them with steel columns, and mark the plane positions of the cranes and steel columns in front. Place the two bridge cranes symmetrically, and securely connect and lock the ends of the first crossbeams in the cranes.

[0026] S3: Bridge crane anchor point connection:

[0027] 1) The first method uses a locking mechanism for quick locking. First, the end of the third arm is placed in the slot. Then, the push plate is moved by rotating the screw, which in turn pushes the end of the third arm to move so that the through hole provided on the third arm is aligned with the through hole on the locking plate. Then, the insertion shaft is inserted into the through hole to fix one end of the two pairs of third arms. Furthermore, the other end of the third arm is fixed and locked with a conventional bolt.

[0028] The second method uses PSB930φ40 fine-rolled threaded steel and mounting bases for tension locking, simulating the tension condition of the first beam anchorage during the lifting process.

[0029] 2) The first fixing blocks at one end of the symmetrical vertical beams are fixedly connected by bolts and nuts;

[0030] S4: Hydraulic jack installation:

[0031] The steel strands in the hydraulic jacks installed at one end of the second crossbeam of each bridge crane are pulled and fixed to the end of the second crossbeam of the symmetrical bridge crane, achieving the effect of mutual pulling between the two bridge cranes to simulate the lifting working conditions; the cables are made of 27 bundles of φ15.24 low-relaxation high-strength steel strands with a standard tensile strength of fpk=1860Mpa, and 13 bundles are installed in a cross-wise manner with 14 bundles rotating in the forward direction to prevent twisting during the load application;

[0032] One end of the first beam serves as the anchor point for the bridge deck. Two methods are available for fixing the beam: the first uses a locking plate and an insert shaft, and the second uses PSB930φ40 finely rolled threaded steel bars and mounting brackets for tension locking, simulating the tension applied to the anchor point of the first beam during the lifting process.

[0033] S5: Tensile test;

[0034] After all preparatory work is checked and found to be correct, the hydraulic jack performs symmetrical tensioning on the steel strands, adopts graded loading, and records the elongation of the steel strands and the displacement of the second beam;

[0035] 1) Preloading stage:

[0036] Initially load to 10% of the design load, maintain the load state for 4-6 minutes, check the initial data of each measuring point, and eliminate system gaps;

[0037] 2) Formal loading stage:

[0038] Loading is carried out in stages according to the design bearing capacity of 20% → 40% → 60% → 80% → 100% → 110%. The load holding time for each stage is: 13-16 minutes for the normal stage, 25-30 minutes for the 100% stage, and 20-25 minutes for the overload stage.

[0039] 3) Strand pulling point movement test: The first electric push rod pushes the mounting base, driving the hydraulic jack and the strand to move. The mounting base is then fixed to the second crossbeam with bolts. The pulling force point is changed, and the test is carried out step by step according to the above-mentioned graded loading method to explore the impact of pulling at different force points on the overall structure of the bridge crane.

[0040] In the pulling test, multiple pulling positions were tested, and the pulling position was determined within the range of 8000-6000mm between the hydraulic jack and the distal end of the second crossbeam. Graded loading tests were carried out at each pulling point to determine the optimal pulling position.

[0041] S6: Displacement monitoring:

[0042] A total station is used to monitor the verticality of the crane in real time, and a laser displacement meter is set up to measure the deflection of the bridge crane;

[0043] S7: Safety Control Measures:

[0044] A three-level early warning system was established: 70% yellow warning, 90% orange warning, and 105% red warning. A 30m safety warning zone was designated, and an audible and visual alarm system was installed.

[0045] S8: Experimental result processing:

[0046] The test data of each level of load sharing are collected and analyzed, and after the test, the second crossbeam, first crossbeam, second inclined beam, first inclined beam and other structural parts are visually inspected to see if there are any weld cracks, bolt failures, etc., and then the test results are judged.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] 1) In this device, two sets of bridge cranes are fixed horizontally and symmetrically, and then pulled against each other using hydraulic jacks. This can simulate the working process of bridge cranes lifting bridges to the greatest extent possible. Therefore, the experimental data obtained is relatively accurate and can maximize the test of the structural strength of the bridge cranes.

[0049] The end of the first crossbeam of the bridge crane is fixed with precision-rolled threaded steel and a mounting bracket, which can simulate the stress conditions between the bridge crane and the bridge anchorage point during the lifting process to the greatest extent possible.

[0050] 2) During the test, a graded loading method is used to conduct tests one by one, which can accurately obtain the stress conditions of the bridge crane and the specific changes that occur on the body during the stress process, and can provide accurate data reference for the construction process; secondly, the hydraulic jack can also change its position on the bridge crane. According to the graded loading method, the impact of different lifting position acceptance points on the bridge crane's main structure can be tested and obtained, thereby accurately judging the load-bearing capacity of the bridge crane and ensuring the smooth progress of construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Attachment Figure 1 This is a schematic diagram of the structure of a pulling test device and method for testing the strength of a bridge crane. Figure 1 ;

[0052] Attachment Figure 2 It is a structural schematic diagram of a test bridge crane of the present invention;

[0053] Attachment Figure 3 Schematic diagram of the structure of the locking plate;

[0054] Attachment Figure 4 This is a schematic diagram of the structure of the vertical beam Figure 1 ;

[0055] Attachment Figure 5 This is a schematic diagram of the structure of the vertical beam Figure 2 ;

[0056] Attachment Figure 6 This is a schematic diagram of the structure of the vertical beam Figure 3 ;

[0057] Attachment Figure 7 is a structural diagram of the second beam;

[0058] Attachment Figure 8 It is a structural diagram of a fixed frame;

[0059] Attachment Figure 9 It is a structural diagram of the second inclined beam;

[0060] Attachment Figure 10 is a structural diagram of the first plugboard;

[0061] Attachment Figure 11 is a schematic cross-sectional structural diagram of the first fork arm;

[0062] Attachment Figure 12 It is a structural diagram of the support beam;

[0063] Attachment Figure 13 This is a schematic diagram of the installation structure of the second crossbeam and the hydraulic jack;

[0064] Attachment Figure 14 is a structural diagram of the third fork arm;

[0065] Attachment Figure 15 This is a schematic diagram of the structure of a pulling test device and method for testing the strength of a bridge crane. Figure 2 ;

[0066] In the figure: 1, first horizontal beam; 11, third support arm; 12, stiffener; 2, second horizontal beam; 3, vertical beam; 4, first oblique beam; 5, second oblique beam; 6, support beam; 7, locking mechanism; 8, hydraulic jack; 81, steel strand; 20, first electric push rod; 30, mounting base; 301, limit block;

[0067] 21. Second support arm; 22. Connecting block; 23. Second electric push rod; 24. Fixed frame; 241. Top plate;

[0068] 31. First support arm; 32. Sleeve; 321. Fixed lug; 311. First fixed block; 312. Second fixed block;

[0069] 51, first fork arm; 511, first slot; 512, first partition plate; 52, second fork arm; 521, mounting block; 522, first plug-in plate; 53, third electric push rod;

[0070] 61, third fork arm; 611, second slot; 612, second partition plate; 62, fourth fork arm;

[0071] 70. Locking plate; 71. Slot; 72. Push plate; 73. Lead screw; 75. Through hole; 74. Insert shaft; 9. Threaded steel bar; DETAILED DESCRIPTION

[0072] To facilitate understanding by those skilled in the art, Figure 1-15 , the technical solution of the present invention is further described in detail.

[0073] Example 1:

[0074] A pulling test device for testing the strength of a bridge crane includes a pair of bridge cranes and a locking mechanism 7. The bridge crane includes a first crossbeam 1, a second crossbeam 2, a first oblique beam 4, a second oblique beam 5 and a vertical beam 3 that are connected to each other; the ends of the vertical beam 3 are fixedly connected to the ends of the first crossbeam 1 and the second crossbeam 2, respectively, and the ends of the first oblique beam 4 are connected to the first crossbeam 1 and the second crossbeam 2, respectively; the ends of the second oblique beam 5 are connected to the first crossbeam 1 and the vertical beam 3; a support beam 6 is provided between the second crossbeam 2 and the second oblique beam 5 to provide supporting force; the end of the second crossbeam 2 is provided with a mounting seat 30, a hydraulic jack 8 and a first electric push rod 20 fixed by bolts, the top shaft of the first electric push rod 20 is connected to the mounting seat 30, the hydraulic jack 8 is fixed on the mounting seat 30, and the hydraulic jack 8 is provided with a steel wire rope 81 for lifting action; further, a rib plate 12 is provided between the first crossbeam 1 and the first oblique beam 4 to provide support.

[0075] The first crossbeam 1 includes a pair of fixedly connected third arms 11; the second crossbeam 2 includes a pair of fixedly connected second arms 21, the second arms 21 are provided with a connecting block 22, the connecting block 22 is fixedly connected to the second arms 21, and the second arms 21 are fixedly connected through the connecting block 22; the second arms 21 are provided with a sleeved fixing frame 24, the fixing frame 24 is provided with a top plate 241, and the top plate 241 is arranged in the gap between the second arms 21; a second electric push rod 23 fixed to the connecting block 22 is provided between the second arms 21, The top shaft of the second electric push rod 23 passes through the connecting block 22 and is fixedly connected to the top plate 241; a limit block 301 is provided on the mounting seat 30, and the limit block 301 is arranged in the gap between the second support arms 21, and the limit block is slidably connected to the second cross beam 2 to limit the sliding trajectory of the mounting seat 30; the steel strand is arranged in the gap between the second support arms; after the bolts of the mounting seat are released, the mounting seat can be pushed by the second electric push rod and the hydraulic jack can be moved on the second cross beam to change the mutually pulling force positions, thereby testing the influence of different force points on the bridge crane structure.

[0076] The locking mechanism 7 includes a locking plate 70 and an insertion shaft 74. The locking plate 70 is provided with a slot 71 and a through hole 75. The slot 71 is provided with a symmetrically distributed push plate 72. The push plate 72 is provided with a rotatably connected screw 73. The screw 73 is threadedly connected to the side of the locking plate 70, and the push plate 72 is pushed to move in the slot 71 by rotating the screw 73.

[0077] The vertical beam 3 includes a pair of fixedly connected first arms 31, a first fixing block 311 is provided at one end of the first arm 31, and a second fixing block 312 is provided at one side of the first arm 31. The second fixing blocks 312 are fixedly connected to each other so that the first arms 31 are connected and fixed as a whole.

[0078] Furthermore, a sleeved square sleeve 32 is provided on the first arm 31 to assist in fixing the first arm 31 and improve the firmness of the connection. The square sleeve 32 is fixed to the first arm 31 by bolts. A connecting fixing ear plate 321 is provided on the square sleeve at one end of the first arm 31.

[0079] The second oblique beam 5 includes a first fork arm 51 and a second fork arm 52 that are plugged into each other; the second fork arm 52 includes a mounting block 521 and a first plug plate 522 fixed to the mounting block 521; the first fork arm 51 is provided with a pair of first slots 511, and a first partition plate 512 is provided between the first slots 511 to ensure the supporting strength; one end of the first fork arm 51 is hingedly connected to the fixing frame 24, and one end of the second fork arm 52 is hingedly connected to the fixing ear plate 321; the first plug plate 522 is plugged into the first slot 511 and then a bolt is passed through the first fork arm 51 and the second fork arm 52, the first plug plate 522, and then fixed with a nut.

[0080] Furthermore, a fixed third electric push rod 53 is provided on the first fork arm 51 , and one end of the top shaft of the third electric push rod 53 is fixedly connected to the mounting block 521 , and the length of the second oblique beam 5 is adjusted by pushing the mounting block 521 .

[0081] The support beam 6 includes a third fork arm 61 and a fourth fork arm 62; a second through slot 611 is provided on the third fork arm 61, and a second partition plate 612 is provided between the second slots 611 to increase the supporting strength, and the fourth fork arm 62 is provided at both ends of the third fork arm 61 and is hingedly connected to the second cross beam 2 and the second oblique beam 5 respectively; one end of the fourth fork arm 62 is inserted into the second slot 611 and then fixed with a nut after passing a bolt through the third fork arm 61 and the fourth fork arm 62.

[0082] During the above installation process, when the first electric push rod 20 pushes the mounting seat 30 and the hydraulic jack 8 to move, the bolt lock of the first fork arm 51 and the second fork arm 52 and the bolt lock of the third fork arm 61 and the fourth fork arm 62 are released, and then the fixed frame 24 can be driven by the push of the second electric push rod 23 to move along the second cross beam 2, thereby changing and adjusting the length of the support beam 6 and the second oblique beam 5, and then locking them with bolts to continue to provide the support effect; the third electric push rod 53 can also provide auxiliary power to adjust the length of the second oblique beam 5, and during this period, close cooperation with the second electric push rod 23 is required.

[0083] Example 2:

[0084] The difference compared with Example 1 is:

[0085] A mounting seat 30 is provided at the end of the first crossbeam 1 , and the symmetrically arranged ends of the first crossbeam 1 are fixed by threaded steel bars 9 interlaced with the mounting seat 30 to simulate the stress position of the bridge crane anchoring the bridge deck.

[0086] A tensile test method for testing the strength of a bridge crane is described as follows:

[0087] S1: Equipment inspection:

[0088] 1) Crane body: Check the structural welds, bolt connections, and pin wear:

[0089] 2) Hydraulic system: confirm that the hydraulic jack has no leakage and the pressure gauge has passed the calibration;

[0090] 3) Site layout: symmetrical spacing of bridge cranes; placement of steel columns that provide load-bearing functions;

[0091] S2: Equipment assembly:

[0092] First, assemble the two bridge cranes. Place them flat on a wide, flat, hardened surface, support them with steel columns, and mark the plane positions of the cranes and steel columns in front. Place the two bridge cranes symmetrically, and securely connect and lock the ends of the first crossbeams in the cranes.

[0093] S3: Bridge crane anchor point connection:

[0094] 1) The first method uses a locking mechanism for quick locking. First, the end of the third arm is placed in the slot. Then, the push plate is moved by rotating the screw, which in turn pushes the end of the third arm to move so that the through hole provided on the third arm is aligned with the through hole on the locking plate. Then, the insertion shaft is inserted into the through hole to fix one end of the two pairs of third arms. Furthermore, the other end of the third arm is fixed and locked with a conventional bolt.

[0095] The second method uses PSB930φ40 fine-rolled threaded steel and mounting brackets for tension locking, simulating the tension condition of the first beam anchorage during the lifting process.

[0096] 2) The first fixing blocks at one end of the symmetrical vertical beams are fixedly connected by bolts and nuts;

[0097] S4: Hydraulic jack installation:

[0098] The steel strands in the hydraulic jacks installed at one end of the second crossbeam of each bridge crane are pulled and fixed to the end of the second crossbeam of the symmetrical bridge crane, achieving the effect of mutual pulling between the two bridge cranes to simulate lifting operations. The cables are made of 27 bundles of φ15.24 low-relaxation, high-strength steel strands with a standard tensile strength of fpk=1860Mpa, and are installed in a cross-installed system with 13 bundles rotating in a forward direction and 14 bundles rotating in a reverse direction to prevent twisting during load application. The hydraulic jacks have a lifting capacity of 300 tons, and the hydraulic circuits of the hydraulic jacks and pump station are equipped with hydraulically controlled check valves and balancing valves. In the event of sudden power outages or other emergencies, the oil circuit can be locked to ensure that the hoisted load is safely suspended at a predetermined height.

[0099] One end of the first beam serves as the anchor point for the bridge deck. Two methods are available for fixing the beam: the first uses a locking plate and an insert shaft, and the second uses PSB930φ40 finely rolled threaded steel bars and mounting brackets for tension locking, simulating the tension applied to the anchor point of the first beam during the lifting process.

[0100] S5: Tensile test;

[0101] After all preparatory work is checked and found to be correct, the hydraulic jack performs symmetrical tensioning on the steel strands, adopts graded loading, and records the elongation of the steel strands and the displacement of the second beam;

[0102] 1) Preloading stage:

[0103] Initially load to 10% of the design load, maintain the load state for 45 minutes, check the initial data of each measuring point, and eliminate system gaps;

[0104] 2) Formal loading stage:

[0105] Load in stages according to the design bearing capacity of 20% → 40% → 60% → 80% → 100% → 110%. The load holding time for each stage is: 10 minutes for the normal stage, 25 minutes for the 100% stage, and 20 minutes for the overload stage.

[0106] 3) Strand pulling point movement test: The first electric push rod pushes the mounting base, driving the hydraulic jack and the strand to move. The mounting base is then fixed to the second crossbeam with bolts. The pulling force point is changed, and the test is carried out step by step according to the above-mentioned graded loading method to explore the impact of pulling at different force points on the overall structure of the bridge crane.

[0107] In this embodiment, the pulling test was conducted at three pulling positions, namely, the hydraulic jack was 8000mm, 7000mm, and 6000mm away from the distal end of the second crossbeam; a graded loading test was conducted at each pulling point to determine the optimal pulling position;

[0108] S6: Displacement monitoring:

[0109] A total station is used to monitor the verticality of the crane in real time, and a laser displacement meter is set to measure the deflection of the bridge crane. The measuring instruments and methods in this step are all existing technologies and will not be described in detail here;

[0110] S7: Safety Control Measures:

[0111] A three-level early warning system was established: 70% yellow warning, 90% orange warning, and 105% red warning. A 30m safety warning zone was designated, and an audible and visual alarm system was installed.

[0112] S8: Experimental result processing:

[0113] The test data of each level of load sharing are collected and analyzed, and after the test, the second crossbeam, first crossbeam, second inclined beam, first inclined beam and other structural parts are visually inspected to see if there are any weld cracks, bolt failures, etc., and then the test results are judged.

[0114] In the description of the present invention, unless otherwise specified, "plurality" means two or more; terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0115] In summary, including but not limited to electric push rods and hydraulic jacks, which are components in the prior art, are obtained through private customization or purchase, and a matching oil station is set up to provide hydraulic power. The electric push rod is a conventional electrical connection and is not within the scope of protection of the present invention.

[0116] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A tensile test device for testing the strength of a bridge crane, comprising a pair of bridge cranes and a locking mechanism, characterized in that The bridge crane includes a first crossbeam, a second crossbeam, a first oblique beam, a second oblique beam and a vertical beam that are connected to each other; the ends of the vertical beam are fixedly connected to the ends of the first crossbeam and the second crossbeam respectively, and the ends of the first oblique beam are connected to the first crossbeam and the second crossbeam respectively; the end of the second oblique beam is connected to the first crossbeam and the vertical beam; a support beam is provided between the second crossbeam and the second oblique beam to provide supporting force; the end of the second crossbeam is provided with a mounting seat fixed by bolts, a hydraulic jack and a first electric push rod, the top shaft of the first electric push rod is connected to the mounting seat, the hydraulic jack is fixed on the mounting seat, and the hydraulic jack is provided with a steel wire rope for lifting; The first beam includes a pair of fixedly connected third arms; the second beam includes a pair of fixedly connected second arms, a connecting block is provided on the second arm, the connecting block is fixedly connected to the second arm, and the second arms are fixedly connected by the connecting block; the second arm is provided with a sleeved fixing frame, the fixing frame is provided with a top plate, and the top plate is provided in the gap between the second arms; a second electric push rod fixed on the connecting block is provided between the second arms, and the top shaft of the second electric push rod is fixedly connected to the top plate after passing through the connecting block; a limit block is provided on the mounting seat, and the limit block is provided in the gap between the second arms, and the limit block is slidably connected to the second beam to limit the sliding trajectory of the mounting seat; the steel strand is provided in the gap between the second arms; after the bolts of the mounting seat are released, the mounting seat can be pushed by the second electric push rod and the hydraulic jack can be moved on the second beam to change the mutually pulling force positions, thereby testing the influence of different force points on the bridge crane structure.

2. A tensile test device for testing the strength of a bridge crane according to claim 1, characterized in that The locking mechanism includes a locking plate and an insertion shaft. The locking plate is provided with a slot and a through hole. The slot is provided with a symmetrically distributed push plate. The push plate is provided with a rotatably connected screw. The screw is threadedly connected to the side of the locking plate. The push plate is pushed to move in the slot by rotating the screw.

3. A tensile test device for testing the strength of a bridge crane according to claim 1, characterized in that The vertical beam includes a pair of fixedly connected first arms, a first fixing block is provided at one end of the first arm, a second fixing block is provided at one side of the first arm, and the second fixing blocks are fixedly connected to each other so that the first arms are connected and fixed as a whole.

4. A tensile test device for testing the strength of a bridge crane according to claim 3, characterized in that The first arm is provided with a sleeved square sleeve to assist in fixing the first arm and improve the firmness of the connection. The square sleeve is fixed to the first arm by bolts. A connecting fixing ear plate is provided on the square sleeve at one end of the first arm.

5. A tensile test device for testing the strength of a bridge crane according to claim 1, characterized in that The second oblique beam includes a first fork arm and a second fork arm plugged into each other; the second fork arm includes a mounting block and a first plug plate fixed to the mounting block; the first fork arm is provided with a pair of first slots, and a first spacer is provided between the first slots to ensure support strength; one end of the first fork arm is hingedly connected to the fixing frame, and one end of the second fork arm is hingedly connected to the fixing ear plate; the first plug plate is plugged into the first slot, and then a bolt is passed through the first fork arm, the second fork arm, and the first plug plate, and then fixed with a nut; A fixed third electric push rod is provided on the first fork arm, and one end of the top shaft of the third electric push rod is fixedly connected to the mounting block, and the length of the second oblique beam is adjusted by pushing the mounting block.

6. A tensile test device for testing the strength of a bridge crane according to claim 1, characterized in that The support beam includes a third fork arm and a fourth fork arm; the third fork arm is provided with a second slot extending therethrough, a second partition plate is provided between the second slots to increase support strength, the fourth fork arm is provided at both ends of the third fork arm and is hingedly connected to the second cross beam and the second oblique beam, respectively; one end of the fourth fork arm is inserted into the second slot and then a bolt is passed through the third fork arm and the fourth fork arm and then fixed with a nut; During the above installation process, when the first electric push rod pushes the mounting seat and the hydraulic jack to move, the bolt locks of the first fork arm, the second fork arm, and the bolt locks of the third fork arm and the fourth fork arm are released, and then the fixed frame can be driven by the push of the second electric push rod to move along the second cross beam, thereby changing the length of the support beam and the second oblique beam, and then locking them with bolts to continue to provide support effects; the third electric push rod can also provide auxiliary power to adjust the length of the second oblique beam, and close cooperation with the second electric push rod is required during this period.

7. A tensile test device for testing the strength of a bridge crane according to claim 1, characterized in that A mounting seat is provided at the end of the first crossbeam. The symmetrically arranged ends of the first crossbeam are fixed by threaded steel bars interspersed with the mounting seat to simulate the stress position of the bridge crane anchoring the bridge deck.

8. A tensile test method for testing the strength of a bridge crane, characterized in that The specific usage is as follows: S1: Equipment inspection: 1) Crane body: Check the structural welds, bolt connections, and pin wear: 2) Hydraulic system: confirm that the hydraulic jack has no leakage and the pressure gauge has passed the calibration; 3) Site layout: symmetrical spacing of bridge cranes; placement of steel columns that provide load-bearing functions; S2: Equipment assembly: First, assemble the two bridge cranes. Place them flat on a wide, flat, hardened surface, support them with steel columns, and mark the plane positions of the cranes and steel columns in front. Place the two bridge cranes symmetrically, and securely connect and lock the ends of the first crossbeams in the cranes. S3: Bridge crane anchor point connection: 1) The first method uses a locking mechanism for quick locking. First, the end of the third arm is placed in the slot. Then, the push plate is moved by rotating the screw, which in turn pushes the end of the third arm to move so that the through hole provided on the third arm is aligned with the through hole on the locking plate. Then, the insertion shaft is inserted into the through hole to fix one end of the two pairs of third arms. Furthermore, the other end of the third arm is fixed and locked with a conventional bolt. The second method uses PSB930φ40 fine-rolled threaded steel and mounting bases for tension locking, simulating the tension condition of the first beam anchorage during the lifting process. 2) The first fixing blocks at one end of the symmetrical vertical beams are fixedly connected by bolts and nuts; S4: Hydraulic jack installation: The steel strands in the hydraulic jacks installed at one end of the second crossbeam of each bridge crane are pulled and fixed to the end of the second crossbeam of the symmetrical bridge crane, achieving the effect of mutual pulling between the two bridge cranes to simulate the lifting working conditions; the cables are made of 27 bundles of φ15.24 low-relaxation high-strength steel strands with a standard tensile strength of fpk=1860Mpa, and 13 bundles are installed in a cross-wise manner with 14 bundles rotating in the forward direction to prevent twisting during the load application; One end of the first beam serves as the anchor point for the bridge deck. Two methods are available for fixing the beam: the first uses a locking plate and an insert shaft, and the second uses PSB930φ40 finely rolled threaded steel bars and mounting brackets for tension locking, simulating the tension applied to the anchor point of the first beam during the lifting process. S5: Tensile test; After all preparatory work is checked and found to be correct, the hydraulic jack performs symmetrical tensioning on the steel strands, adopts graded loading, and records the elongation of the steel strands and the displacement of the second beam; S6: Displacement monitoring: A total station is used to monitor the verticality of the crane in real time, and a laser displacement meter is set up to measure the deflection of the bridge crane; S7: Safety Control Measures: A three-level early warning system was established: 70% yellow warning, 90% orange warning, and 105% red warning. A 30m safety warning zone was designated, and an audible and visual alarm system was installed. S8: Experimental result processing: The test data of each level of load sharing are collected and analyzed, and after the test, the second crossbeam, first crossbeam, second inclined beam, first inclined beam and other structural parts are visually inspected to see if there are any weld cracks, bolt failures, etc., and then the test results are judged.

9. A tensile test method for testing the strength of a bridge crane according to claim 8, characterized in that Step S5 is divided into three stages: 1) Preloading stage: Initially load to 10% of the design load, maintain the load state for 4-6 minutes, check the initial data of each measuring point, and eliminate system gaps; 2) Formal loading stage: Loading is carried out in stages according to the design bearing capacity of 20% → 40% → 60% → 80% → 100% → 110%. The load holding time for each stage is: 13-16 minutes for the normal stage, 25-30 minutes for the 100% stage, and 20-25 minutes for the overload stage. 3) Strand pulling point movement test: The first electric push rod pushes the mounting base, driving the hydraulic jack and the strand to move. The mounting base is then fixed to the second crossbeam with bolts. The pulling force point is changed, and the test is carried out step by step according to the above-mentioned graded loading method to explore the impact of pulling at different force points on the overall structure of the bridge crane. In the pulling test, pulling tests were carried out at multiple pulling positions, and the pulling position points were determined within the position range of 8000-6000mm where the hydraulic jack was away from the far end of the second crossbeam; graded loading tests were carried out at each pulling point in turn to determine the optimal pulling position.

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