A construction method for cantilever erection of prefabricated steel box girders

Abstract

This application relates to the field of steel box girder construction, and relates to a construction method for cantilever erection of prefabricated steel box girders, which includes the following steps: prefabricating steel box girders; lifting the prefabricated steel box girders by a hoisting device and moving them to a designated position on the pier; the hoisting device includes a crane body and a connecting block fixedly connected to the crane body; a first hook and a second hook are hinged to the connecting block, a hanging ring is installed on the steel box girder, the hanging ring is placed between the first hook and the second hook, and a locking member for locking the first hook and the second hook is installed on the connecting block; connecting two adjacent steel box girders; unlocking the locking member, and separating the first hook, the second hook and the hanging ring; repeating the above steps to hoist the remaining steel box girders. This application improves the problem of poor safety of the staff.

Description

Technical Field

[0001] The present application relates to the field of steel box girder construction, and in particular to a method for cantilever erection construction of precast steel box girders. Background Technique

[0002] At present, steel box girders are lighter than concrete girders and have been widely used in the construction of long-span cable-stayed bridges and suspension bridges at home and abroad. Due to different bridge structural forms, bridge site terrain conditions, shipping conditions, and transportation conditions, their erection methods are also different. The conventional methods for installing steel box girders of cross-river bridges at home and abroad are as follows: Under the condition of floating transportation, a large floating crane is equipped as a lifting device and installed by the support erection method; or the steel box girder is transported to the bridge position by a tugboat and then cantilever assembled by a deck crane, and it can also be installed by jacking with a temporary pier.

[0003] In the related art, the method for cantilever erection construction of steel box girders includes the following steps: S1, prefabricating steel box girders; S2, lifting the prefabricated steel box girders by a crane and moving them to a designated position on the pier to unhook; S3, performing bolt welding connection on two prefabricated steel box girders and welding the bottom plate of the bolt-welded steel box girders; S4, after welding is completed, separating the hook of the crane from the bolt-welded steel box girders; S5, repeating steps S2, S3, and S4 to hoist the remaining prefabricated steel box girders.

[0004] In view of the above related art, when the steel box girder is welded, it is necessary for workers to manually separate the hook of the crane from the bolt-welded steel box girders. Since the operating environment of the workers is relatively complex, the lifting equipment is likely to cause harm to the workers, resulting in poor safety of the workers. Summary of the Invention

[0005] In order to improve the problem of poor safety of workers, the present application provides a method for cantilever erection construction of precast steel box girders.

[0006] The method for cantilever erection construction of precast steel box girders provided by the present application adopts the following technical solutions:

[0007] A method for cantilever erection construction of precast steel box girders includes the following steps:

[0008] Prefabricating steel box girders;

[0009] Lifting the prefabricated steel box girders by a lifting device and moving them to a designated position on the pier; the lifting device includes a crane body and a connecting plate fixedly connected to the crane body; a first hook and a second hook are hinged to the connecting plate, a hanging ring is installed on the steel box girder, the hanging ring is placed between the first hook and the second hook, and a locking member for locking the first hook and the second hook is installed on the connecting plate;

[0010] Connect two adjacent steel box girders.

[0011] Unlock the locking component, and separate the first hook, the second hook from the hanging ring.

[0012] Repeat the above steps to hoist the remaining steel box girders.

[0013] By adopting the above technical solution, only by operating the locking component can the locking of the first hook and the second hook by the locking component be released, and the hanging ring can be separated from the first hook and the second hook, thus completing the separation of the hoisting equipment from the steel box girder, reducing the occurrence of the situation where the staff directly operates on the hoisting equipment and the steel box girder, and improving the problem of poor safety of the staff.

[0014] Preferably, the locking component includes a first locking rod and a second locking rod penetrating through the connecting plate; a first locking groove for inserting the first locking rod is formed on the side wall of the first hook, and a second locking groove for inserting the second locking rod is formed on the side wall of the second hook; a control component for controlling the movement of the first locking rod and the second locking rod is installed on the connecting plate.

[0015] By adopting the above technical solution, when the control component is started, the control component can drive the first locking rod and the second locking rod to move simultaneously. When the first locking rod and the second locking rod are respectively disengaged from the first locking groove and the second locking groove, the locking of the first locking rod on the first hook and the locking of the second locking rod on the second hook are released, thus facilitating the operation of the staff.

[0016] Preferably, the control component includes a fixing plate fixedly connected to the connecting plate, a control plate fixedly connected to the first locking rod, and an electromagnet fixedly connected to the fixing plate; the control plate is fixedly connected to the second locking rod, and an iron sheet used in cooperation with the electromagnet is fixedly connected to the control plate; a storage battery is fixedly connected to the fixing plate, and the storage battery is electrically connected to the electromagnet through a wire; a control spring is fixedly connected to the control plate, and the control spring is fixedly connected to the connecting plate; a switch component for controlling the energization and de-energization of the storage battery to the electromagnet is installed on the steel box girder.

[0017] By adopting the above technical solution, when the steel box girder is placed on the pier, the switch component can control the battery to energize the electromagnet, the electromagnet attracts the iron sheet, the iron sheet drives the control board to move, the control board drives the first locking rod and the second locking rod to move, and the first locking rod and the second locking rod can be disengaged from the first locking groove and the second locking groove respectively. Then, the crane body is controlled to move the connecting plate, and the connecting plate can drive the first hook and the second hook to move, so that the lifting equipment is separated from the steel box girder, reducing the operation steps of the staff and further improving the problem of poor safety of the staff.

[0018] Preferably, a first inclined surface is formed on the end surface of the first locking rod facing the first hook, and the first inclined surface can contact the side of the first hook; a second inclined surface is formed on the end surface of the second locking rod facing the second hook, and the second inclined surface can contact the side of the second hook.

[0019] By adopting the above technical solution, when the hanging ring needs to be locked, first place the hanging ring between the first hook and the second hook, and then move the first hook and the second hook closer to each other. When the first hook contacts the first inclined surface and the second hook contacts the second inclined surface, continue to move the first hook and the second hook. The first hook pushes the first locking rod to move, and the second hook pushes the second locking rod to move. At this time, the control spring is in a stretched state. When the first locking rod is opposite to the first locking groove and the second locking rod is opposite to the second locking groove, the control spring can pull the first locking rod and the second locking rod to insert into the first locking groove and the second locking groove respectively to lock the first hook and the second hook, and the first hook and the second hook lock the hanging ring, reducing the operation steps of the staff.

[0020] Preferably, a switch hole is vertically formed on the steel box girder. The switch component includes a switch board detachably installed on the inner wall of the switch hole, a switch spring fixedly connected to the switch board, and a switch block fixedly connected to the switch spring; the switch block extends to the outside of the steel box girder, and the switch block can abut against the pier; a first contact is arranged on the switch block, and the first contact is electrically connected to the battery through a wire; a second contact is arranged on the switch board and is used in cooperation with the first contact, and the second contact is electrically connected to the electromagnet through a wire.

[0021] By adopting the above technical solution, during the process of placing the steel box girder on the pier, when the switch block contacts the pier, the steel box girder continues to move, the switch block moves relative to the steel box girder, and the switch block drives the second contact to move. When the second contact contacts the first contact, the battery energizes the electromagnet. At this time, the steel box girder is placed on the pier, and the lifting equipment can be separated from the steel box girder, thus improving the problem of poor safety of the staff.

[0022] Preferably, a first support rod is hinged to the first hook, and a second support rod is hinged to the second hook. One end of the first support rod away from the first hook is hinged to a connecting block, the second support rod is hinged to the connecting block, and a fixing component is installed on the first support rod for locking the connecting block and the first support rod.

[0023] By adopting the above technical solution, during the process of the hanging ring detaching from the first hook and the second hook, the hanging ring drives the first hook and the second hook to separate from each other. The first hook drives the first support rod to move, the second hook drives the second support rod to move, and the first support rod and the second support rod drive the connecting block to move vertically. When the hanging ring detaches from the first hook and the second hook, the fixing component can lock the connecting block and the first support rod. The first support rod and the second support rod still remain in an open state. When the hanging ring is put into the first hook and the second hook next time, the step of opening the first support rod and the second support rod is reduced, improving the working efficiency of the staff.

[0024] Preferably, the fixing component includes a fixing block fixedly connected to the first support rod and a fixing rod inserted through the fixing block; a connecting groove for inserting the fixing rod is formed on the side wall of the connecting block. A pulling plate is fixedly connected to the end face of the fixing rod away from the connecting block. A fixing spring is sleeved on the fixing rod. One end of the fixing spring is fixedly connected to the pulling plate, and the other end of the fixing spring is fixedly connected to the fixing block.

[0025] By adopting the above technical solution, during the movement of the first support rod, the first support rod drives the fixing block to move, and the fixing block drives the fixing rod to move. When the fixing rod abuts against the connecting block, the first support rod continues to move, and the connecting block pushes the fixing rod to move. At this time, the fixing spring is in a stretched state. When the fixing rod is opposite to the connecting groove, the fixing spring can push the fixing rod to insert into the connecting groove, thus completing the locking between the connecting block and the first support rod.

[0026] Preferably, a sliding groove is formed on the side wall of the connecting block on the same side as the connecting groove. The top of the sliding groove communicates with the connecting groove, and the bottom of the sliding groove is through; a sliding block is slidably placed in the sliding groove. The bottom of the sliding block can abut against the hanging ring. The top of the sliding block extends into the connecting groove. A third inclined surface is formed on the end face of the fixing rod away from the pulling plate, and the third inclined surface can contact the side of the top of the sliding block.

[0027] By adopting the above technical solution, during the process of putting the hanging ring into the first hook and the second hook, when the hanging ring abuts against the sliding block, the hanging ring continues to move, the hanging ring pushes the sliding block to move, and the sliding block pushes the fixing rod to move through the third inclined surface. When the fixing rod disengages from the connecting groove, at this time the sliding block stops moving, and the hanging ring pushes the connecting block to move through the sliding block. The connecting block drives the first support rod and the second support rod to move, and the first support rod and the second support rod respectively drive the first hook and the second hook to move, so that the first hook and the second hook approach each other, thereby being able to lock the hanging ring, reducing the operation steps of the staff to move the first hook and the second hook, and further improving the work efficiency of the staff.

[0028] Preferably, a dovetail block is fixedly connected to the sliding block, and a dovetail groove for placing the dovetail block is formed on the side wall of the sliding groove.

[0029] By adopting the above technical solution, the dovetail block restricts the movement track of the sliding block and improves the stability of the sliding block during movement.

[0030] Preferably, a clamping ring is fixedly connected to the side wall of the switch board, a clamping groove for cooperating with the clamping ring is formed on the inner wall of the switch hole, and a handle is fixedly connected to the switch board.

[0031] By adopting the above technical solution, by moving the handle, the handle drives the switch board to move, and the switch board can be taken out of the switch hole, which is convenient for the staff to operate.

[0032] In summary, the present application includes at least one of the following beneficial technical effects:

[0033] 1. By setting the locking component, the first hook and the second hook in the present application, only by operating the locking component, the unlocking of the locking component on the first hook and the second hook can be released, and the hanging ring can be disengaged from the first hook and the second hook, thereby completing the separation of the hoisting equipment and the steel box girder, reducing the occurrence of the situation where the staff directly operates on the hoisting equipment and the steel box girder, and improving the problem of poor safety of the staff;

[0034] 2. By setting the first locking rod and the second locking rod in the present application, when the control component is started, the control component can drive the first locking rod and the second locking rod to move simultaneously. When the first locking rod and the second locking rod disengage from the first locking groove and the second locking groove respectively, the locking of the first locking rod on the first hook and the locking of the second locking rod on the second hook are released, thereby facilitating the operation of the staff;

[0035] 3. In this application, by setting an electromagnet and an iron sheet, when the steel box girder is placed on the pier, the switch component can control the battery to energize the electromagnet. The electromagnet attracts the iron sheet, and the iron sheet drives the control board to move. The control board drives the first locking rod and the second locking rod to move. The first locking rod and the second locking rod can be disengaged from the first locking groove and the second locking groove respectively. Then, control the crane body to move the connecting block. The connecting block can drive the first hook and the second hook to move, so that the hoisting equipment is separated from the steel box girder, reducing the operation steps of the staff and further improving the problem of poor safety of the staff. Brief Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the overall structure of the prefabricated steel box girder cantilever erection construction method according to the embodiment of this application.

[0037] Figure 2 It is a schematic diagram of the structure of the hoisting equipment according to the embodiment of this application.

[0038] Figure 3 It is a schematic diagram of the structure of the locking component according to the embodiment of this application.

[0039] Figure 4 It is a schematic diagram of the structure of the switch component according to the embodiment of this application.

[0040] Figure 5 It is a schematic diagram of the structure of the fixing component according to the embodiment of this application.

[0041] Description of the reference numerals: 1, steel box girder; 11, hanging ring; 12, switch hole; 121, clamping groove; 2, hoisting equipment; 21, crane body; 22, connecting plate; 23, first hook; 231, first locking groove; 24, second hook; 241, second locking groove; 25, first support rod; 26, second support rod; 27, connecting block; 271, connecting groove; 272, sliding groove; 273, dovetail groove; 3, locking component; 31, first locking rod; 311, first inclined surface; 32, second locking rod; 321, second inclined surface; 4, control component; 41, fixing plate; 42, control board; 43, electromagnet; 44, iron sheet; 45, battery; 46, control spring; 5, switch component; 51, switch board; 511, clamping ring; 512, handle; 52, switch spring; 53, switch block; 54, first contact; 55, second contact; 6, fixing component; 61, fixing block; 62, fixing rod; 621, third inclined surface; 63, pulling plate; 64, fixing spring; 7, sliding block; 71, dovetail block. Detailed Description of the Embodiment

[0042] The following is a further detailed description of this application in conjunction with the attached Figures 1-5 drawings.

[0043] An embodiment of the present application discloses a construction method for cantilever erection of precast steel box girders. Refer to Figure 1 and Figure 2 , the construction method for cantilever erection of precast steel box girders includes the following steps:

[0044] S1. Precast the steel box girder 1;

[0045] S2. Lift the precast steel box girder 1 by a hoisting device 2 and move it to a designated position on the pier; the hoisting device 2 includes a crane body 21, a connecting plate 22, a first hook 23 and a second hook 24; the connecting plate 22 is fixedly connected to the crane body 21; the first hook 23 and the second hook 24 are hinged to the side walls on the same side of the connecting plate 22, and the opposite side walls of the first hook 23 and the second hook 24 are inner arc surfaces; a hanging ring 11 is installed on the steel box girder 1, the hanging ring 11 is fixedly connected to the steel box girder 1 through a hanging rope, the hanging ring 11 is placed between the first hook 23 and the second hook 24, and both the first hook 23 and the second hook 24 can pass through the hanging ring 11; a locking member 3 is installed on the connecting plate 22, and the locking member 3 can lock the first hook 23 and the second hook 24, so that the first hook 23 and the second hook 24 fix the hanging ring 11.

[0046] S3. Connect two adjacent steel box girders 1;

[0047] S4. Unlock the locking member 3, and the hanging ring 11 is separated from the first hook 23 and the second hook 24, completing the separation of the hoisting device 2 and the steel box girder 1, reducing the occurrence of direct operation of the hoisting device 2 and the steel box girder 1 by the staff, and improving the problem of poor safety of the staff;

[0048] S5. Repeat steps S2, S3 and S4 to hoist the remaining steel box girders 1.

[0049] Refer to Figure 2 and Figure 3, the locking component 3 includes a first locking rod 31 and a second locking rod 32; the first locking rod 31 is inserted through the side wall of the connecting plate 22, a first locking groove 231 is formed on the side wall of the first hook 23, the first locking rod 31 is inserted into the first locking groove 231, and the first locking rod 31 locks the first hook 23; the second locking rod 32 is inserted through the side wall of the connecting plate 22, a second locking groove 241 is formed on the side wall of the second hook 24, the second locking rod 32 is inserted into the second locking groove 241, and the second locking rod 32 locks the second hook 24; a control component 4 is installed on the connecting plate 22. When the control component 4 can control the first locking rod 31 and the second locking rod 32 to disengage from the first locking groove 231 and the second locking groove 241 respectively, the locking of the first locking rod 31 on the first hook 23 and the locking of the second locking rod 32 on the second hook 24 are released.

[0050] The control component 4 includes a fixing plate 41, a control plate 42, an electromagnet 43, an iron sheet 44, a storage battery 45 and a control spring 46; the fixing plate 41 is fixedly connected to the side wall of the connecting plate 22 away from the second hook 24; the control plate 42 is fixedly connected to the side wall of the first locking rod 31 away from the first hook 23, and the control plate 42 is fixedly connected to the second locking rod 32; the electromagnet 43 is fixedly connected to the end face of the fixing plate 41; the iron sheet 44 is fixedly connected to the side wall of the control plate 42, and the iron sheet 44 is used in cooperation with the electromagnet 43; the storage battery 45 is fixedly connected to the side wall of the fixing plate 41, the storage battery 45 is electrically connected to the electromagnet 43 through a wire, the storage battery 45 can energize the electromagnet 43, the electromagnet 43 attracts the iron sheet 44, the iron sheet 44 drives the control plate 42 to move, the control plate 42 drives the first locking rod 31 and the second locking rod 32 to move, so that the first locking rod 31 and the second locking rod 32 disengage from the first locking groove 231 and the second locking groove 241 respectively; the control spring 46 is fixedly connected to the side wall of the control plate 42, and the control spring 46 is fixedly connected to the connecting plate 22. During the movement of the control plate 42, the control spring 46 is in a stretched state. When the storage battery 45 cuts off the power supply to the electromagnet 43, the control spring 46 drives the control plate 42 to return to the initial position.

[0051] Refer to Figure 3, a first inclined surface 311 is formed on the end surface of the first locking rod 31 away from the control board 42. The first inclined surface 311 can contact the side of the inner arc surface of the first hook 23. During the process of the first hook 23 rotating towards the second hook 24, the first hook 23 first abuts against the first inclined surface 311. Continuing to move the first hook 23, the first hook 23 pushes the first locking rod 31 to move. At this time, the control spring 46 is in a stretched state. When the first locking rod 31 is opposite to the first locking groove 231, the control spring 46 can pull the first locking rod 31 into the first locking groove 231, thus completing the locking of the first locking rod 31 to the first hook 23 and reducing the operation steps of the staff; a second inclined surface 321 is formed on the end surface of the second locking rod 32 away from the control board 42. The second inclined surface 321 can contact the side of the inner arc surface of the second hook 24. Repeating the above operation can complete the locking of the second locking rod 32 to the second hook 24.

[0052] Refer to Figure 3 and Figure 4 , a switch hole 12 is vertically opened on the end surface of the steel box girder 1. A switch component 5 is installed on the steel box girder 1. The switch component 5 can control the battery 45 to supply power to and cut off the power of the electromagnet 43. The switch component 5 includes a switch board 51, a switch spring 52, a switch block 53, a first contact 54, and a second contact 55; the switch board 51 is placed in the switch hole 12. A clamping ring 511 is fixedly connected to the side wall of the switch board 51. The clamping ring 511 is made of rubber. A clamping groove 121 is opened on the inner wall of the switch hole 12. The clamping ring 511 is placed in the clamping groove 121 to fix the switch board 51. A handle 512 is fixedly connected to the switch board 51. The handle 512 extends to the outside of the steel box girder 1 for facilitating the movement of the switch board 51; the switch spring 52 is fixedly connected to the end surface of the switch board 51. The switch spring 52 extends to the outside of the steel box girder 1; the switch block 53 is fixedly connected to the switch spring 52. The switch block 53 is located outside the steel box girder 1. The switch block 53 can abut against the bridge pier; the first contact 54 is arranged on the switch block 53. The first contact 54 is electrically connected to the battery 45 through a wire. During the process of the steel box girder 1 being placed on the bridge pier, when the switch block 53 contacts the bridge pier, the steel box girder 1 continues to move, the switch block 53 moves relative to the steel box girder 1, and the switch block 53 drives the second contact 55 to move; the second contact 55 is arranged on the switch board 51. The second contact 55 is used in cooperation with the first contact 54. The second contact 55 is electrically connected to the electromagnet 43 through a wire. When the second contact 55 contacts the first contact 54, the battery 45 supplies power to the electromagnet 43. At this time, the steel box girder 1 is placed on the bridge pier, improving the problem of poor safety of the staff.

[0053] Refer to Figure 3 and Figure 5, the hoisting device 2 further includes a first support rod 25, a second support rod 26 and a connecting block 27; the first support rod 25 is hinged to the inner arc surface of the first hook 23; the second support rod 26 is hinged to the inner arc surface of the second hook 24; the connecting block 27 is hinged to one end of the first support rod 25 away from the first hook 23, and one side of the connecting block 27 away from the first support rod 25 is hinged to the second support rod 26, and the first support rod 25 and the second support rod 26 are symmetrically arranged along the connecting block 27; a fixing member 6 is installed on the first support rod 25. When the first support rod 25 and the second support rod 26 are in an open state, the fixing member 6 can lock the connecting block 27 and the first support rod 25, so that the first support rod 25 and the second support rod 26 remain in an open state. The next time the hanging ring 11 is placed in the first hook 23 and the second hook 24, the steps of opening the first support rod 25 and the second support rod 26 are reduced.

[0054] Refer to Figure 5 , the fixing member 6 includes a fixing block 61, a fixing rod 62, a pulling plate 63 and a fixing spring 64; the fixing block 61 is fixedly connected to the side wall of the first support rod 25; the fixing rod 62 is inserted through the side wall of the fixing block 61, and the fixing rod 62 is parallel to the first support rod 25. A connecting groove 271 is formed on the side wall of the connecting block 27, and the fixing rod 62 can be inserted into the connecting groove 271; the pulling plate 63 is fixedly connected to the end face of the fixing rod 62 away from the connecting block 27; the fixing spring 64 is sleeved on the fixing rod 62, one end of the fixing spring 64 is fixedly connected to the pulling plate 63, and the other end of the fixing spring 64 is fixedly connected to the fixing block 61; during the process of the hanging ring 11 disengaging from the first hook 23 and the second hook 24, the hanging ring 11 drives the first hook 23 and the second hook 24 to separate from each other, the first hook 23 drives the first support rod 25 to move, the first support rod 25 drives the fixing rod 62 to move. When the fixing rod 62 abuts against the connecting block 27, the first support rod 25 continues to move, and the connecting block 27 pushes the fixing rod 62 to move. At this time, the fixing spring 64 is in a stretched state. When the fixing rod 62 is opposite to the connecting groove 271, the fixing spring 64 can push the fixing rod 62 into the connecting groove 271, thereby completing the locking between the connecting block 27 and the first support rod 25.

[0055] Refer to Figure 5, a sliding groove 272 is formed on the side wall of the connecting block 27 on the same side as the connecting groove 271. The top of the sliding groove 272 communicates with the connecting groove 271, the bottom of the sliding groove 272 is through-shaped, and a dovetail groove 273 is formed on the side wall of the sliding groove 272; a sliding block 7 is slidably placed in the sliding groove 272, and a dovetail block 71 is fixedly connected to the side wall of the sliding block 7. The dovetail block 71 is placed in the dovetail groove 273. The dovetail block 71 limits the movement track of the sliding block 7. The top of the sliding block 7 extends into the connecting groove 271, and the bottom of the sliding block 7 can abut against the hanging ring 11. During the process of placing the hanging ring 11 into the first hook 23 and the second hook 24, the hanging ring 11 can push the sliding block 7 to move; a third inclined surface 621 is formed on the end surface of the fixed rod 62 away from the pulling plate 63. The third inclined surface 621 can contact the side of the top of the sliding block 7. The sliding block 7 pushes the fixed rod 62 to move through the third inclined surface 621. When the fixed rod 62 disengages from the connecting groove 271, the sliding block 7 stops moving at this time. The hanging ring 11 pushes the connecting block 27 to move through the sliding block 7. The connecting block 27 drives the first support rod 25 and the second support rod 26 to move. The first support rod 25 and the second support rod 26 respectively drive the first hook 23 and the second hook 24 to move, so that the first hook 23 and the second hook 24 approach each other, thereby being able to lock the hanging ring 11.

[0056] The implementation principle of a prefabricated steel box girder cantilever erection construction method in an embodiment of the present application is as follows: When it is necessary to use the hoisting device 2 to lift the steel box girder 1, first place the hanging ring 11 between the first hook 23 and the second hook 24. When the hanging ring 11 abuts against the sliding block 7, the hanging ring 11 continues to move, and the hanging ring 11 pushes the sliding block 7 to move. The sliding block 7 pushes the fixed rod 62 to move through the third inclined surface 621. When the fixed rod 62 disengages from the connecting groove 271, the sliding block 7 stops moving at this time; the hanging ring 11 pushes the connecting block 27 to move through the sliding block 7. The connecting block 27 drives the first support rod 25 and the second support rod 26 to move. The first support rod 25 and the second support rod 26 respectively drive the first hook 23 and the second hook 24 to move, so that the first hook 23 and the second hook 24 approach each other; when the first hook 23 contacts the first inclined surface 311 and the second hook 24 contacts the second inclined surface 321, the first hook 23 pushes the first locking rod 31 to move, and the second hook 24 pushes the second locking rod 32 to move. At this time, the control spring 46 is in a stretched state. When the first locking rod 31 is opposite to the first locking groove 231 and the second locking rod 32 is opposite to the second locking groove 241; the control spring 46 can pull the first locking rod 31 and the second locking rod 32 to be inserted into the first locking groove 231 and the second locking groove 241 respectively, to lock the first hook 23 and the second hook 24. The first hook 23 and the second hook 24 lock the hanging ring 11, reducing the operation steps of the staff.

[0057] During the process of placing the steel box girder 1 on the pier, when the switch block 53 contacts the pier, the steel box girder 1 continues to move, the switch block 53 moves relative to the steel box girder 1, the switch block 53 drives the second contact 55 to move, and when the second contact 55 contacts the first contact 54, the storage battery 45 energizes the electromagnet 43. At this time, the steel box girder 1 is placed on the pier; the electromagnet 43 attracts the iron sheet 44, the iron sheet 44 drives the control board 42 to move, the control board 42 drives the first locking rod 31 and the second locking rod 32 to move, and the first locking rod 31 and the second locking rod 32 can respectively disengage from the first locking groove 231 and the second locking groove 241. Then, the crane body 21 is controlled to move the connecting plate 22, and the connecting plate 22 can drive the first hook 23 and the second hook 24 to move away from each other, so that the hanging ring 11 disengages from the first hook 23 and the second hook 24, completing the separation of the hoisting device 2 and the steel box girder 1, and improving the problem of poor safety of the staff;

[0058] The first hook 23 drives the first support rod 25 to move, the second hook 24 drives the second support rod 26 to move, the first support rod 25 and the second support rod 26 drive the connecting block 27 to move vertically, the first support rod 25 drives the fixed block 61 to move, the fixed block 61 drives the fixed rod 62 to move, and when the fixed rod 62 abuts against the connecting block 27; the first support rod 25 continues to move, the connecting block 27 pushes the fixed rod 62 to move, and at this time the fixed spring 64 is in a stretched state. When the fixed rod 62 is opposite to the connecting groove 271, the fixed spring 64 can push the fixed rod 62 into the connecting groove 271, thus completing the locking between the connecting block 27 and the first support rod 25, making the first support rod 25 and the second support rod 26 continuously in an open state. When the hanging ring 11 is placed in the first hook 23 and the second hook 24 next time, the step of opening the first support rod 25 and the second support rod 26 is reduced, improving the working efficiency of the staff.

[0059] The above are all preferred embodiments of this application, and the protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A construction method for cantilever erection of precast steel box girders, characterized in that, it includes the following steps: Precast steel box girder (1); Lift the precast steel box girder (1) by a hoisting device (2) and move it to a designated position on the pier; the hoisting device (2) includes a crane body (21) and a connecting plate (22) fixedly connected to the crane body (21); a first hook (23) and a second hook (24) are hingedly connected to the connecting plate (22), a hanging ring (11) is installed on the steel box girder (1), and the hanging ring (11) is placed between the first hook (23) and the second hook (24), and a locking component (3) for locking the first hook (23) and the second hook (24) is installed on the connecting plate (22); Connect two adjacent steel box girders (1); Unlock the locking component (3), and separate the first hook (23), the second hook (24) from the hanging ring (11); Repeat the above steps to hoist the remaining steel box girders (1); The locking component (3) includes a first locking rod (31) and a second locking rod (32) inserted through the connecting plate (22); a first locking groove (231) for inserting the first locking rod (31) is formed on the side wall of the first hook (23), and a second locking groove (241) for inserting the second locking rod (32) is formed on the side wall of the second hook (24); a control component (4) for controlling the movement of the first locking rod (31) and the second locking rod (32) is installed on the connecting plate (22); The control component (4) includes a fixing plate (41) fixedly connected to the connecting plate (22), a control plate (42) fixedly connected to the first locking rod (31), and an electromagnet (43) fixedly connected to the fixing plate (41); the control plate (42) is fixedly connected to the second locking rod (32), and an iron sheet (44) used in cooperation with the electromagnet (43) is fixedly connected to the control plate (42); a storage battery (45) is fixedly connected to the fixing plate (41), and the storage battery (45) is electrically connected to the electromagnet (43) through a wire; a control spring (46) is fixedly connected to the control plate (42), and the control spring (46) is fixedly connected to the connecting plate (22); a switch component (5) for controlling the storage battery (45) to supply power to and cut off power from the electromagnet (43) is installed on the steel box girder (1); A switch hole (12) is vertically formed in the steel box girder (1). The switch component (5) includes a switch plate (51) detachably installed on the inner wall of the switch hole (12), a switch spring (52) fixedly connected to the switch plate (51), and a switch block (53) fixedly connected to the switch spring (52); the switch block (53) extends to the outside of the steel box girder (1), and the switch block (53) can be in contact with the bridge pier; a first contact (54) is arranged on the switch block (53), and the first contact (54) is electrically connected to the storage battery (45) through a wire; a second contact (55) cooperating with the first contact (54) is arranged on the switch plate (51), and the second contact (55) is electrically connected to the electromagnet (43) through a wire.

2. A method for cantilever erection construction of a precast steel box girder according to claim 1, characterized in that: A first inclined surface (311) is formed on the end surface of the first locking rod (31) facing the first hook (23), and the first inclined surface (311) can be in contact with the side of the first hook (23); a second inclined surface (321) is formed on the end surface of the second locking rod (32) facing the second hook (24), and the second inclined surface (321) can be in contact with the side of the second hook (24).

3. A method for cantilever erection construction of a precast steel box girder according to claim 1, characterized in that: A first support rod (25) is hinged to the first hook (23), a second support rod (26) is hinged to the second hook (24), one end of the first support rod (25) away from the first hook (23) is hinged to a connection block (27), the second support rod (26) is hinged to the connection block (27), and a fixing component (6) for locking the connection block (27) and the first support rod (25) is installed on the first support rod (25).

4. A method for cantilever erection construction of a precast steel box girder according to claim 3, characterized in that: The fixing component (6) includes a fixing block (61) fixedly connected to the first support rod (25) and a fixing rod (62) inserted through the fixing block (61); a connection groove (271) for inserting the fixing rod (62) is formed on the side wall of the connection block (27), a pull plate (63) is fixedly connected to the end surface of the fixing rod (62) away from the connection block (27), a fixing spring (64) is sleeved on the fixing rod (62), one end of the fixing spring (64) is fixedly connected to the pull plate (63), and the other end of the fixing spring (64) is fixedly connected to the fixing block (61).

5. A method for cantilever erection construction of a precast steel box girder according to claim 4, characterized in that: On the side wall of the connecting block (27) on the same side as the connecting groove (271), a sliding groove (272) is formed. The top of the sliding groove (272) communicates with the connecting groove (271), and the bottom of the sliding groove (272) is through; a sliding block (7) is slidably placed in the sliding groove (272). The bottom of the sliding block (7) can abut against the hanging ring (11). The top of the sliding block (7) extends into the connecting groove (271). A third inclined surface (621) is formed on the end surface of the fixing rod (62) away from the pulling plate (63), and the third inclined surface (621) can contact the side of the top of the sliding block (7).

6. A prefabricated steel box girder cantilever erection construction method according to claim 5, characterized in that: A dovetail block (71) is fixedly connected to the sliding block (7), and a dovetail groove (273) for placing the dovetail block (71) is formed on the side wall of the sliding groove (272).

7. A prefabricated steel box girder cantilever erection construction method according to claim 1, characterized in that: A clamping ring (511) is fixedly connected to the side wall of the switch plate (51). A clamping groove (121) for cooperating with the clamping ring (511) is formed on the inner wall of the switch hole (12). A handle (512) is fixedly connected to the switch plate (51).

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