Steel box girder spanning over ramp on complex support system and construction method

Abstract

The present invention relates to a steel box girder spanning a ramp on a complex support system and a construction method thereof. The construction steps include: (1) installation of a temporary steel pipe support system; (2) installation of a temporary internal support frame for the steel box girder segments; (3) installation of a guiding frame for aerial splicing of the steel box girder; (4) installation of the steel box girder by double-crane lifting; (5) precise positioning construction of the steel box girder segments; and (6) removal of the temporary steel pipe support system. The present invention ensures the safety of the existing ramp structure and the steel box girder, improves the installation accuracy and construction quality of the steel box girder segments, and can achieve good technical and economic benefits when applied to actual construction.

Description

Technical Field

[0001] The present invention relates to the construction of a steel box girder, and particularly to a steel box girder spanning a ramp on a complex support system and a construction method thereof. Background Art

[0002] In recent years, the construction projects of bridges spanning existing ramps have been increasing day by day, resulting in a significantly increased construction difficulty, making the selection of the design and construction schemes of bridge projects particularly important. Due to its advantages such as high tensile strength, light self-weight, and short construction period, the steel box girder is increasingly widely used in the construction of such bridges.

[0003] However, it is found during the bridge construction process that the rooting and erection of the steel box girder support spanning the ramp are difficult, resulting in low construction efficiency of the steel box girder. In addition, a simple steel box girder hoisting scheme is difficult to ensure the safety of the existing ramp structure and the steel box girder, which puts higher requirements on the steel box girder hoisting technology. And due to the influence of the existing ramp, it is difficult to ensure the installation accuracy and quality of the steel box girder segments. Therefore, how to optimize the design and construction scheme according to the actual situation on site and seek a construction method for the steel box girder spanning the ramp on a complex support system with high construction quality and fast construction efficiency under the condition of ensuring the safe passage of the existing ramp is of great significance. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a steel box girder spanning a ramp on a complex support system and a construction method thereof.

[0005] To achieve the above technical purpose, the present invention adopts the following technical solutions: A construction method for a steel box girder spanning a ramp on a complex support system, and its construction steps are as follows:

[0006] Step 1: Installation of the temporary steel pipe support system: The foundation treatment of the temporary support adopts a strip-shaped concrete foundation. The steel pipe support system is assembled, hoisted, adjusted and then accepted for use; for the main bridge of the intersection section spanning the ramp, the steel pipe support system needs to be set on the bridge deck of the existing steel box girder. During the installation construction, two second crossbeams are set on the existing steel box girder, and the steel pipe support system is connected above the two second crossbeams. A sliding groove is formed by grooving on the second crossbeam, and a guide beam is installed on the existing steel box girder. The guide beam passes through the sliding groove on the second crossbeam; the second crossbeam and the existing steel box girder are fixed by welding right-angle connectors; a transmission rod is arranged on the side of the transport trolley, and the transmission rod is connected to the second crossbeam. The assembled steel pipe support system is driven by the trolley traction to slide along the guide beam to the designated position, and then the steel pipe support system and the existing steel box girder are fixed by welding right-angle connectors.

[0007] Step 2. Installation of the temporary internal bracing for the steel box girder segment: The temporary internal bracing includes a fixing block, a base, an internal connecting block, and a lead screw. The base is set on the fixing block and connected to the internal connecting block. Adjusting shafts are provided on both sides and the upper end of the fixing block. One end of the lead screw is fixed to the top plate, and the other end is connected to the adjusting shaft. Threaded holes are provided on the adjusting shaft, and the lead screw passes through the threaded holes. A connecting shaft is rotatably connected to the fixing block and arranged corresponding to the lead screw. A second vertical rod is rotatably connected to the adjusting shaft. One end of the second vertical rod is connected to a knob, and the other end is connected to a first gear. One end of the connecting shaft is fixedly connected to a second gear, which is located inside the adjusting shaft. The first gear and the second gear are meshed. A spring is connected between the second gear and the end of the lead screw. By rotating the knob, the top plate is tightened against the inner side of the steel box girder segment to prevent deformation during the hoisting of the steel box girder segment.

[0008] Step 3. Installation of the aerial splicing guiding frame for the steel box girder: The aerial splicing guiding frame includes an L-shaped bracket and an inclined support. Two sleeves are welded on each upper positioning block, and one sleeve is welded on each lower positioning block. The inclined support is tightly connected to the sleeve through the thread provided at the end. The length of the inclined support is extended through a flange plate. A number of positioning grooves are evenly arranged on the L-shaped bracket. The upper positioning block and the lower positioning block are respectively placed in the positioning grooves and fixedly connected by bolts. During the hoisting of the steel box girder segment, a guiding block is welded on one of the L-shaped brackets, and a limiting track is welded on the other L-shaped bracket. The cross-section of the guiding block is in a "T" shape, and a slot matching the guiding block is provided in the limiting track. The two L-shaped brackets are respectively fixed to two adjacent steel box girder segments. During hoisting, the guiding block on one L-shaped bracket is placed in the limiting track of the other L-shaped bracket.

[0009] Step 4. Double-crane hoisting installation of the steel box girder: When hoisting the steel box girder of the overpass ramp, the double-crane hoisting method is adopted to smoothly cross the existing ramp. The two cranes are respectively connected to two lifting rings. Two pairs of inclined rods are installed on the steel box girder segment. A tie rod is welded between each pair of inclined rods. A cross bar is welded between the tops of the two pairs of inclined rods. Two lifting discs are installed on the cross bar. A lifting ring is welded on the top of the lifting disc for the two cranes to hoist the steel box girder segment respectively. The top of the first vertical rod is connected to the lifting disc, and the bottom is fixed to the steel box girder through a sleeve. A cross frame is welded between adjacent first vertical rods. The steel box girder is hoisted from the middle to both sides, and the two side flange plates are hoisted last.

[0010] Step 5. Precise positioning construction of the steel box girder segment: The height adjustment of the steel box girder segment is achieved through steel pads and jacks. The jacks are installed on the first cross beam. The steel box girder segment is hoisted and placed on the jacks, and the height of the steel box girder segment is adjusted through the jacks. Steel pads are provided between the steel box girder segment and the first cross beam. A limiting frame is installed on the first cross beam to conduct rough lateral positioning of the steel box girder segment. A lateral precise positioning device is provided between adjacent steel box girder segments.

[0011] Step 6. Demolition of the steel pipe support system: For the support system installed on the concrete foundation, two truck cranes are used to demolish it in sections during disassembly; for the demolition construction of the steel pipe support system on the existing steel box girder, first remove the right-angle connectors, and then use the transport trolley to tow the entire steel pipe support system to slide along the guide beam to the end of the guide beam. Then, lift the entire steel pipe support system to the ground and demolish it in sections.

[0012] Preferably, in Step 1, a V-shaped support is arranged on the upper part of the transport trolley, a first anti-falling column is installed on the V-shaped support, a second anti-falling column is installed on the second cross beam, and a reinforcing steel wire rope is arranged between the first anti-falling column and the second anti-falling column.

[0013] Preferably, in Step 4, state detectors are arranged at both ends of the cross bar; the state detectors are connected to the anti-falling device through data transmission lines, and the data transmission lines are built into the bearings. A reinforcing steel wire rope is arranged on the anti-falling device and is located inside the vertical pole. The reinforcing steel wire rope is connected to the steel box girder segment; during the hoisting process of the steel box girder segment, when the state detector monitors that the hoisting support formed by the inclined rods breaks, it will trigger the anti-falling device arranged inside the lifting tray, so that the reinforcing steel wire rope originally in an unloaded and bent state inside the vertical pole is tightened and stressed, ensuring the smooth landing of the steel box girder segment.

[0014] Preferably, in Step 5, the transverse precise positioning device includes a sliding track, a moving support block, and a jack. One end of the sliding track is provided with a bottom plate, and the bottom plate is placed in a reserved groove arranged on the first connecting plate. The bottom plate and the first connecting plate are fixedly connected by bolts; moving blocks are welded on both sides of the moving support block, and the moving blocks are placed inside the sliding track and can move along the axial direction of the sliding track. The other end of the sliding track is provided with a second connecting plate, and the second connecting plate is rotationally connected to the sliding track through a rotating shaft; a first jack limiting groove and a second jack limiting groove are respectively arranged on the moving support block and the second connecting plate, and the jack is installed between the moving support block and the second connecting plate. The first jack limiting groove and the second jack limiting groove are used to place both ends of the jack for precisely positioning the position of the jack; after the hoisting of the left and right adjacent steel box girder segments is completed, the assembled transverse precise positioning device is placed on the steel box girder segment, and the steel box girder segment is driven to move horizontally through the jack, thereby realizing the transverse precise positioning of the steel box girder segment.

[0015] A steel box girder spanning the ramp on a complex support system is constructed by the construction method of the steel box girder spanning the ramp on a complex support system.

[0016] The present invention has the following characteristics and beneficial effects:

[0017] 1. The present invention adopts the anti-slip technology for the hoisting points of double-crane lifting, sets up a state detector to monitor the real-time stress condition of the hoisting bracket. When unsafe conditions such as the fracture of the bracket occur, the anti-falling device is triggered, so that the originally unloaded and bent reinforcement steel ropes inside the vertical pole are tightened and stressed, and the reinforcement steel ropes play a role in supporting and limiting the steel box girder segment, ensuring the smooth landing of the steel box girder and improving the safety during the use of the lifting tool.

[0018] 2. The present invention sets up an aerial splicing guiding frame for the hoisting of vertically layered ultra-high steel box girders, installs positioning grooves to flexibly adjust the support angle of the inclined support, and uses the guiding blocks and limiting tracks arranged on the L-shaped bracket to accurately position the vertical position of the steel box girder. The guiding frame is convenient for assembly and installation, improving the construction efficiency.

[0019] 3. The present invention adopts the deformation prevention and control technology for the temporary internal support frame, sets up a temporary internal support frame. By rotating the knob forward or backward, the vertical pole drives the first gear to rotate forward or backward, so that the first gear drives the second gear to rotate backward accordingly. At the same time, under the action of the spring, the length of the screw rod extends outward and contracts inward, making the top plate tightly press against the inner side of the steel box girder to prevent the steel box girder from deforming during the hoisting process.

[0020] 4. The present invention sets up a horizontal precise positioning device. After the hoisting of the left and right adjacent steel box girders is completed, the assembled device is placed on the steel box girder, uses the sliding track to adjust the horizontal position of the jack limiting groove, and realizes the horizontal movement of the beam segment through the jack to achieve the horizontal precise positioning of the steel box girder.

[0021] 5. The present invention adopts the technology of integral installation and disassembly of the guiding beam for the steel box girder bridge support on the overpass ramp. The assembled steel pipe support system is driven by the transport trolley to slide along the guiding beam to the designated position. In order to prevent the transmission rod from malfunctioning and unable to continue to support and move during the movement of the trolley, the reinforcement steel rope formed by connecting with the anti-falling column forms a second traction barrier to ensure the smooth installation and disassembly of the steel pipe support system on the bridge. Description of the Drawings

[0022] Figure 1 is the plan view of the steel box girder on the overpass ramp with a complex support system;

[0023] Figure 2 is the structural schematic diagram of the aerial splicing guiding frame and the anti-slip technology for the hoisting points;

[0024] Figure 3 is the structural schematic diagram of the anti-slip technology for the hoisting points of double-crane lifting;

[0025] Figure 4 is the cross-sectional view of the lifting ring vertical pole;

[0026] Figure 5 is the structural schematic diagram during the construction of the aerial splicing guiding frame;

[0027] Figure 6 It is a schematic structural diagram of the aerial splicing guide frame;

[0028] Figure 7 It is a schematic structural diagram of the diagonal brace of the aerial splicing guide frame;

[0029] Figure 8 It is a schematic structural diagram of the temporary internal support frame;

[0030] Figure 9 It is a cross-sectional view of the temporary internal support frame;

[0031] Figure 10 It is a schematic structural diagram of the transverse precise positioning device before assembly;

[0032] Figure 11 It is a schematic structural diagram of the assembled transverse precise positioning device;

[0033] Figure 12 It is a schematic structural diagram of the overall installation and disassembly of the transverse movement of the guide beam on the upper cross-ramp steel box girder bridge support.

[0034] In the figure: 1 - concrete foundation, 2 - steel pipe support system, 3 - first cross beam, 4 - flange plate, 5 - temporary internal support frame, 6 - steel box girder segment, 7 - steel cushion block, 8 - jack, 9 - limit frame, 10 - second cross beam, 11 - overall installation and disassembly system for transverse movement of the guide beam, 12 - existing steel box girder, 13 - diagonal rod, 14 - connecting rod, 15 - status detector, 16 - lifting ring, 17 - lifting plate, 18 - bearing, 19 - first vertical rod, 20 - sleeve, 21 - cross frame, 22 - cross bar, 23 - splicing guide frame, 24 - anti-falling device, 25 - reinforcing steel rope, 26 - L-shaped support, 27 - lower positioning block, 28 - diagonal brace, 29 - guide block, 30 - limit track, 31 - upper positioning block, 32 - positioning groove, 33 - flange plate, 34 - top plate, 35 - lead screw, 36 - knob, 37 - fixed block, 38 - adjusting shaft, 39 - second vertical rod, 40 - first gear, 41 - second gear, 42 - connecting shaft, 43 - spring, 44 - internal connecting block, 45 - base, 46 - first limit groove of the jack, 47 - reserved groove, 48 - first connecting plate, 49 - moving support block, 50 - moving block, 51 - sliding track, 52 - second limit groove of the jack, 53 - second connecting plate, 54 - rotating shaft, 55 - bottom plate, 56 - guide beam, 57 - first anti-falling column, 58 - right-angle connecting piece, 59 - sliding groove, 60 - fixed screw, 61 - second anti-falling column, 62 - transmission rod, 63 - V-shaped support, 64 - transport trolley. Specific implementation manners

[0035] The present invention will be further described below in conjunction with embodiments, and traditional construction methods such as welding and installation will not be elaborated. The description of the following embodiments is only used to help understand the present invention. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0036] Figure 1 is a plan view of the steel box girder spanning the ramp on a complex support system; Figure 2 is a structural schematic diagram of the guiding frame for in-air splicing of the steel box girder and the anti-slip technology for the lifting points; Figure 3 is a structural schematic diagram of the anti-slip technology for the lifting points of double-crane lifting; Figure 4 is a cross-sectional view of the lifting ring vertical pole; Figure 5 is a structural schematic diagram during the construction of the guiding frame for in-air splicing; Figure 6 is a structural schematic diagram of the guiding frame for in-air splicing; Figure 7 is a structural schematic diagram of the inclined support of the guiding frame for in-air splicing; Figure 8 is a structural schematic diagram of the temporary internal support; Figure 9 is a cross-sectional view of the temporary internal support; Figure 10 is a structural schematic diagram before the assembly of the transverse precise positioning device; Figure 11 is a structural schematic diagram after the assembly of the transverse precise positioning device; Figure 12 is a structural schematic diagram of the overall installation and disassembly of the transverse movement of the guide beam of the bridge support for the steel box girder spanning the ramp.

[0037] As shown in the figures, the steel box girder of the complex support system straddles the ramp, including a concrete foundation 1, a steel pipe support system 2, a first cross beam 3, a flange plate 4, a temporary internal support 5, a steel box girder segment 6, a steel spacer 7, a jack 8, a limit frame 9, a second cross beam 10, a guide beam transverse movement integral installation and disassembly system 11, an existing steel box girder 12, a diagonal rod 13, a tie rod 14, a state detector 15, a lifting ring 16, a lifting plate 17, a bearing 18, a first vertical rod 19, a sleeve 20, a cross frame 21, a cross bar 22, a splicing guide frame 23, a fall arrester 24, a reinforcing steel rope 25, an L-shaped support 26, a lower positioning block 27, an inclined support 28, a guide block 29, a limit track 30, an upper positioning block 31, a positioning groove 32, a flange plate 33, a top plate 34, a lead screw 35, a knob 36, a fixed block 37, an adjusting shaft 38, a second vertical rod 39, a first gear 40, a second gear 41, a connecting shaft 42, a spring 43, an internal connecting block 44, a base 45, a first limit groove of the jack 46, a reserved groove 47, a first connecting plate 48, a moving support block 49, a moving block 50, a sliding track 51, a second limit groove of the jack 52, a second connecting plate 53, a rotating shaft 54, a bottom plate 55, a guide beam 56, a first anti-falling column 57, a right-angle connecting piece 58, a sliding groove 59, a fixed screw 60, a second anti-falling column 61, a transmission rod 62, a V-shaped support 63, a transport trolley 64; The steel box girder of the complex support system straddles the ramp adopts a double-crane lifting anti-slip technology for the lifting points; The steel box girder of the complex support system straddles the ramp is provided with an aerial splicing guide frame; The steel box girder of the complex support system straddles the ramp adopts a deformation prevention and control technology for the temporary internal support; The steel box girder of the complex support system straddles the ramp is provided with a horizontal precise positioning device; The bridge support of the steel box girder of the complex support system straddles the ramp adopts a guide beam transverse movement integral installation and disassembly technology.

[0038] Double-crane lifting anti-slip technology for lifting points. Two pairs of diagonal rods 13 are installed on the steel box girder segment 6. A connecting rod 14 is welded between each pair of diagonal rods 13 to strengthen the connection. A cross bar 22 is welded between the tops of the two pairs of diagonal rods 13 to form a lifting bracket. Two lifting discs 17 are installed on the cross bar 22. A lifting ring 16 is welded on the top of the lifting disc 17, which are respectively used for two cranes to lift the steel box girder segment 6. The top of the first vertical rod 19 is connected to the lifting disc 17, and the bottom is fixed to the steel box girder through a sleeve 20. A cross frame 21 is welded between adjacent first vertical rods 19. State detectors 15 are arranged at both ends of the cross bar 22. The state detectors 15 are connected to the anti-falling device 24 through a data transmission line, and the data transmission line is built into the bearing 18. The anti-falling device 24 is provided with a reinforcing steel rope 25. The reinforcing steel rope 25 is located inside the first vertical rod 19 and is connected to the steel box girder segment 6. During the lifting process of the steel box girder segment 6, when the state detector 15 monitors an unsafe condition such as the fracture of the lifting bracket formed by the diagonal rods 13, it will trigger the anti-falling device 24 arranged inside the lifting disc 17, so that the reinforcing steel rope 25 originally in an unloaded and bent state inside the first vertical rod 19 is tightened and stressed, and the reinforcing steel rope 25 is used to support and limit the steel box girder segment 6, ensuring the stable landing of the steel box girder segment 6 and improving the safety during the use of the lifting tool.

[0039] The aerial splicing guide frame 23 includes an L-shaped bracket 26 and an inclined support 28. Two sleeves 20 are welded on each upper positioning block 31, and one sleeve 20 is welded on each lower positioning block 27. The inclined support 28 is tightly connected to the sleeve 20 through a thread provided at the end. The length of the inclined support 28 is extended through a flange 33. A number of positioning grooves 32 are evenly arranged on the L-shaped bracket 26. According to the construction requirements, the upper positioning block 31 and the lower positioning block 27 are respectively placed in the positioning grooves 32 and fixedly connected by bolts. When the steel box girder segment 6 is lifted, a guide block 29 is welded on one L-shaped bracket 26, and a limit track 30 is welded on the other L-shaped bracket 26. The cross section of the guide block 29 is in a "T" shape, and a slot matching the guide block 29 is provided in the limit track 30. The two L-shaped brackets 26 are respectively fixed to two adjacent steel box girder segments 6. During the lifting process, the guide block 29 on one L-shaped bracket 26 is placed in the limit track 30 of the other L-shaped bracket 26 to accurately position the vertical position of the steel box girder.

[0040] The deformation prevention and control technology of the temporary internal support realizes the internal support for the steel box girder segment 6 through the temporary internal support 5. The temporary internal support 5 includes a fixed block 37, a base 45, an internal connection block 44, and a lead screw 35. The base 45 is arranged on the fixed block 37, the base 45 is connected to the internal connection block 44, and the internal connection block 44 is located inside the fixed block 37. Adjusting shafts 38 are provided on both sides and the upper end of the fixed block 37, and the adjusting shafts 38 are hollow shafts. One end of the lead screw 35 is fixed to the top plate 34, and the other end is connected to the adjusting shaft 38. Among them, a threaded hole is provided on the adjusting shaft 38, and the lead screw 35 passes through the threaded hole. A connecting shaft 42 is rotatably connected to the fixed block 37, the connecting shaft 42 is arranged corresponding to the lead screw 35, and the connecting shaft 42 can rotate relative to the fixed block 37 but cannot axially move relative to the fixed block 37. A second vertical rod 39 is rotatably connected to the adjusting shaft 38. One end of the second vertical rod 39 is connected to the knob 36, and the other end is connected to the first gear 40. The first gear 40 is located inside the adjusting shaft 38. One end of the connecting shaft 42 is fixedly connected to the second gear 41, the second gear 41 is located inside the adjusting shaft 38, and the first gear 40 and the second gear 41 are meshed. A spring 43 is connected between the second gear 41 and the end of the lead screw 35. When the temporary internal support 5 is installed inside the steel box girder, by rotating the knob 36 in the forward direction, the second vertical rod 39 drives the first gear 40 to rotate in one direction, so that the first gear 40 drives the second gear 41 and the connecting shaft 42 to rotate synchronously. When the connecting shaft 42 rotates, it drives the lead screw 35 to rotate in one direction, so that the length of the lead screw 35 contracts and moves inward, and the spring 43 contracts. When the knob 36 is rotated in the other direction, the second vertical rod 39 drives the first gear 40 to rotate, drives the second gear 41 and the connecting shaft 42 to rotate synchronously through the first gear 40. When the connecting shaft 42 rotates, it drives the lead screw 35 to rotate in the other direction, and the spring 43 elongates, so that the lead screw 35 extends outward. In this way, the top plate 34 presses tightly against the inner side of the steel box girder segment 6, preventing the steel box girder from deforming during the hoisting process and ensuring the construction quality.

[0041] The horizontal precise positioning device includes a sliding track 51, a moving support block 49, and a jack 8. One end of the sliding track 51 is provided with a bottom plate 55, and the bottom plate 55 is placed in a reserved groove 47 provided on the first connecting plate 48. The bottom plate 55 and the first connecting plate 48 are fixedly connected by bolts. Moving blocks 50 are welded on both sides of the moving support block 49. The moving blocks 50 are placed in the sliding track 51 and can move along the axial direction of the sliding track 51. The horizontal displacement is adjusted by the movement of the moving blocks 50. The other end of the sliding track 51 is provided with a second connecting plate 53, and the second connecting plate 53 is rotatably connected to the sliding track 51 through a rotating shaft 54. A first jack limiting groove 46 and a second jack limiting groove 52 are respectively provided on the moving support block 49 and the second connecting plate 53. The jack 8 is installed between the moving support block 49 and the second connecting plate 48. The first jack limiting groove 46 and the second jack limiting groove 52 are used to place the two ends of the jack, and are used to precisely position the jack 8. After the hoisting of the adjacent steel box girder segments 6 on the left and right is completed, the assembled device is placed on the steel box girder, and the lateral movement of the beam segment is realized through the jack 8, so as to achieve the horizontal precise positioning of the steel box girder segment 6.

[0042] The overall installation, disassembly and transverse movement technology of the guide beam is realized through the overall installation, disassembly and transverse movement system 11 of the guide beam. The overall installation, disassembly and transverse movement system 11 of the guide beam includes a second cross beam 10, a steel pipe support system 2, a guide beam 56, and a transport trolley 64. Two second cross beams 10 are arranged on the existing steel box girder 12, and the steel pipe support system 2 is installed on the two second cross beams 10. The steel pipe support system 2 is horizontally connected above the two second cross beams 10. A sliding groove 59 is formed by grooving on the second cross beam 10. The guide beam 56 is installed on the existing steel box girder 12. The guide beam 56 is arranged along the length direction of the guide beam 56, and the guide beam 56 passes through the sliding groove 59 on the second cross beam 10. The second cross beam 10 and the existing steel box girder 12 are fixed by welding a right-angle connecting piece 58. At the same time, a fixing screw 60 is arranged on the right-angle connecting piece 58, and the fixing screw 60 presses against the right-angle connecting piece 58 and the second cross beam 10 to strengthen the connection. A transmission rod 62 is arranged on the side of the transport trolley 64, and the transmission rod 62 is connected to the second cross beam 10. A V-shaped support 63 is arranged on the upper part of the transport trolley 64, and a first anti-falling column 57 is installed on the support. A second anti-falling column 61 is installed on the second cross beam 10. A reinforcing steel wire rope 25 is arranged between the first anti-falling column 57 and the second anti-falling column 61. For the installation construction of the steel pipe support system 2 on the existing steel box girder 12, the transport trolley 64 is connected to the entire steel pipe support system 2 through the transmission rod 62. The assembled steel pipe support system 2 is driven by the transport trolley 64 to slide along the guide beam 56 to the designated position, and the right-angle connecting piece 58 is welded between the second guide beam 10 and the existing steel box girder 12 for fixation. For the demolition construction of the steel pipe support system 2 on the existing steel box girder 12, first, the right-angle connecting piece 58 is removed. The steel pipe support system 2 is driven by the transport trolley 64 to slide along the guide beam 56 to the end of the guide beam 56. Finally, the steel pipe support system 2 is hoisted to the ground as a whole and then demolished. In order to prevent the transmission rod 62 from failing and being unable to continue towing during the movement of the transport trolley 64, the reinforcing steel wire rope 25 formed by connecting with the anti-falling column is used to form a second traction barrier to ensure the smooth demolition of the steel pipe support system 2 on the bridge.

[0043] The present invention also provides a construction method for a ramp steel box girder straddling a complex support system. The main construction steps are as follows:

[0044] Step 1. Installation of the temporary steel pipe support system 2: The foundation treatment of the temporary support adopts a strip-shaped concrete foundation 1. The steel pipe support system 2 is assembled, hoisted, adjusted and then accepted for use. For the main bridge of the intersection section of the overpass ramp, the steel pipe support system needs to be installed on the deck of the existing steel box girder 12. During the installation construction, two second crossbeams 10 are set on the existing steel box girder 12, and the steel pipe support system 2 is connected above the two second crossbeams 10. A sliding groove 59 is formed by grooving on the second crossbeam 10, and a guide beam 56 is installed on the existing steel box girder 12. The guide beam 56 is arranged along the length direction of the guide beam 56, and the guide beam 56 passes through the sliding groove 59 on the second crossbeam 10. The second crossbeam 10 and the existing steel box girder 12 are fixed by welding right-angle connectors 58.

[0045] A transmission rod 62 is arranged on the side of the transport trolley 64. The transmission rod 62 is connected to the second crossbeam 10. The transport trolley 64 is connected to the entire steel pipe support system 2 through the transmission rod 62. A V-shaped support 63 is arranged on the upper part of the transport trolley 64, and a first anti-falling column 57 is installed on the V-shaped support 63. A second anti-falling column 61 is installed on the second crossbeam 10. A reinforcing steel rope 25 is arranged between the first anti-falling column 57 and the second anti-falling column 61. The assembled steel pipe support system 2 is driven by the trolley to slide along the guide beam 56 to the designated position, and then the right-angle connector 58 is welded and fixed between the steel pipe support system 2 and the existing steel box girder 12. In order to prevent the transmission rod 62 from failing and being unable to continue towing during the movement of the transport trolley 64, the reinforcing steel rope 25 formed by connecting with the anti-falling column forms a second traction barrier to ensure the smooth installation of the steel pipe support system 2 on the existing bridge.

[0046] Step 2. Installation of the temporary internal support 5 for the steel box girder segment 6: The temporary internal support 5 includes a fixed block 37, a base 45, an internal connection block 44, and a lead screw 35. The base 45 is arranged on the fixed block 37 and is connected to the internal connection block 44; adjusting shafts 38 are arranged on both sides and the upper end of the fixed block 37; one end of the lead screw 35 is fixed to the top plate 34, and the other end is connected to the adjusting shaft 38; a threaded hole is arranged on the adjusting shaft 38, and the lead screw 35 passes through the threaded hole; a connecting shaft 42 is rotatably connected to the fixed block 37, and the connecting shaft 42 is arranged corresponding to the lead screw 35; a second vertical rod 39 is rotatably connected to the adjusting shaft 38, one end of the second vertical rod 39 is connected to a knob 36, and the other end is connected to a first gear 40; one end of the connecting shaft 42 is fixedly connected to a second gear 41, the second gear 41 is located inside the adjusting shaft 38, and the first gear 40 and the second gear 41 are meshed; a spring 43 is connected between the second gear 41 and the end of the lead screw 35; when the temporary internal support 5 is installed inside the steel box girder, by rotating the knob 36 in the forward direction, the second vertical rod 39 drives the first gear 40 to rotate in one direction, so that the first gear 40 drives the second gear 41 and the connecting shaft 42 to rotate synchronously. When the connecting shaft 42 rotates, it drives the lead screw 35 to rotate in one direction, causing the length of the lead screw 35 to contract and move inward, and the spring 43 contracts; when the knob 36 is rotated in the other direction, the second vertical rod 39 drives the first gear 40 to rotate, drives the second gear 41 and the connecting shaft 42 to rotate synchronously through the first gear 40. When the connecting shaft 42 rotates, it drives the lead screw 35 to rotate in the other direction, and the spring 43 elongates, causing the lead screw 35 to extend outward; by rotating the knob 36, the top plate 34 is tightened against the inner side of the steel box girder segment 6 to prevent the steel box girder segment 6 from deforming during the hoisting process and ensure the construction quality.

[0047] Step 3. Installation of the aerial splicing guide frame 23 for the steel box girder: The aerial splicing guide frame 23 includes an L-shaped bracket 26 and an inclined support 28. Two sleeves 20 are welded on each upper positioning block 31, and one sleeve 20 is welded on each lower positioning block 27. The inclined support 28 is tightly connected to the sleeve 20 through the thread arranged at the end; the length of the inclined support 28 is extended through a flange 33; a number of positioning grooves 32 are evenly arranged on the L-shaped bracket 26. According to the construction requirements, the upper positioning block 31 and the lower positioning block 27 are respectively placed in the positioning grooves 32 and fixedly connected by bolts; when the steel box girder segment 6 is hoisted, a guide block 29 is welded on one of the L-shaped brackets 26, and a limiting track 30 is welded on the other L-shaped bracket 26. The cross-section of the guide block 29 is in the shape of a "T", and a slot matching the guide block 29 is arranged in the limiting track 30. The two L-shaped brackets 26 are respectively fixed to two adjacent steel box girder segments 6. During the hoisting process, the guide block 29 on one of the L-shaped brackets 26 is placed in the limiting track 30 of the other L-shaped bracket 26 to accurately position the vertical position of the steel box girder.

[0048] Step 4. Double-crane hoisting and installation of steel box girder: When hoisting the steel box girder of the overpass ramp, use double-crane hoisting to smoothly cross the existing ramp, and the two cranes are respectively connected to the two lifting rings 16; in order to ensure the stability of the steel box girder hoisting process, adopt the anti-slip technology for the hoisting points of double-crane hoisting. Install two pairs of diagonal rods 13 on the steel box girder segment 6, weld a connecting rod 14 between each pair of diagonal rods 13 to strengthen the connection, and weld a cross bar 22 between the tops of the two pairs of diagonal rods 13 to form a hoisting support; install two lifting discs 17 on the cross bar 22, weld a lifting ring 16 at the top of the lifting disc 17, and use them respectively for the two cranes to hoist the steel box girder segment 6; connect the top of the first vertical rod 19 to the lifting disc 17, and fix the bottom to the steel box girder through a sleeve 20; weld a cross frame 21 between adjacent first vertical rods 19; install a state detector 15 at both ends of the cross bar 22; the state detector 15 is connected to the anti-falling device 24 through a data transmission line, and the data transmission line is built into the bearing 18. The anti-falling device 24 is provided with a reinforcing steel rope 25, and the reinforcing steel rope 25 is located inside the first vertical rod 19 and is connected to the steel box girder segment 6; when the steel box girder segment 6 is being hoisted, if the state detector 15 monitors an unsafe condition such as the fracture of the hoisting support formed by the diagonal rods 13, it will trigger the anti-falling device 24 installed inside the lifting disc 17, so that the reinforcing steel rope 25 that was originally in an unloaded and bent state inside the first vertical rod 19 is tightened and stressed, and the reinforcing steel rope 25 is used to support and limit the steel box girder segment 6, ensuring the smooth landing of the steel box girder segment 6 and improving the safety when using the lifting tool; the steel box girder is hoisted from the middle to both sides, and the two side flange plates 4 are the last to be hoisted and constructed.

[0049] Step 5. Precise positioning construction of the steel box girder segment 6: The height adjustment of the steel box girder segment 6 is achieved through steel pads 7 and jacks 8. The jacks 8 are installed on the first cross beam 3. The steel box girder segment 6 is hoisted and placed on the jacks 8, and the height of the steel box girder segment 6 is adjusted through the jacks 8. Steel pads 7 are arranged between the steel box girder segment 6 and the first cross beam 3; A limit frame 9 is installed on the first cross beam 3, and the steel box girder segment 6 is roughly positioned laterally through the limit frame 9; A lateral precise positioning device is arranged between adjacent steel box girder segments 6 for precise positioning; The lateral precise positioning device includes a sliding track 51, a moving support block 49, and a jack 8. One end of the sliding track 51 is provided with a bottom plate 55, and the bottom plate 55 is placed in a reserved groove 47 provided on the first connecting plate 48. The bottom plate 55 and the first connecting plate 48 are fixedly connected by bolts; Moving blocks 50 are welded on both sides of the moving support block 49. The moving blocks 50 are placed in the sliding track 51 and can move along the axial direction of the sliding track 51. The other end of the sliding track 51 is provided with a second connecting plate 53, and the second connecting plate 53 is rotatably connected to the sliding track 51 through a rotating shaft 54; A first jack limit groove 46 and a second jack limit groove 52 are respectively arranged on the moving support block 49 and the second connecting plate 53. The jack 8 is installed between the moving support block 49 and the second connecting plate 53. The first jack limit groove 46 and the second jack limit groove 52 are used to place the two ends of the jack for precisely positioning the position of the jack 8; After the hoisting of the left and right adjacent steel box girder segments 6 is completed, the assembled lateral precise positioning device is placed on the steel box girder, and the steel box girder segment 6 is driven to move laterally through the jack 8 to achieve the lateral precise positioning of the steel box girder segment 6.

[0050] Step 6. Demolition of the steel pipe support system 2: For the support system installed on the concrete foundation 1, two truck cranes are used to demolish it in sections during disassembly; For the demolition construction of the steel pipe support system 2 on the existing steel box girder 12, first, the right-angle connecting piece 58 is removed, and the entire steel pipe support system 2 is driven by a transport trolley 64 to slide along the guide beam 56 to the end of the guide beam 56, and then the steel pipe support system 2 is hoisted as a whole to the ground and demolished in sections; In order to prevent the transmission rod 62 from malfunctioning and being unable to continue towing during the movement of the transport trolley 64, a second traction barrier is formed by using the reinforcing steel rope 25 connected to the anti-falling column to ensure the smooth demolition of the steel pipe support system 2 on the existing steel box girder 12.

Claims

1. A construction method for a steel box girder spanning an interchange ramp on a complex support system, characterized in that, The construction steps are as follows: Step 1. Installation of the temporary steel pipe support system (2): The foundation treatment of the temporary support adopts a strip-shaped concrete foundation (1). After the steel pipe support system (2) is assembled, hoisted, and adjusted, it is accepted for use. For the main bridge of the intersection section of the overpass ramp, the steel pipe support system (2) needs to be installed on the bridge deck of the existing steel box girder (12). During the installation construction, two second crossbeams (10) are set on the existing steel box girder (12), and the steel pipe support system (2) is connected above the two second crossbeams (10). A sliding groove (59) is formed by grooving on the second crossbeam (10). A guide beam (56) is installed on the existing steel box girder (12), and the guide beam (56) passes through the sliding groove (59) on the second crossbeam (10). The second crossbeam (10) and the existing steel box girder (12) are fixed by welding a right-angle connecting piece (58). A transmission rod (62) is arranged on the side of the transport trolley (64), and the transmission rod (62) is connected to the second crossbeam (10). The assembled steel pipe support system (2) is driven by the trolley traction to slide to the designated position along the guide beam (56), and then the right-angle connecting piece (58) is welded between the steel pipe support system (2) and the existing steel box girder (12) for fixation; Step 2. Installation of the temporary internal support (5) for the steel box girder segment (6): The temporary internal support (5) includes a fixed block (37), a base (45), an internal connecting block (44), and a lead screw (35). The base (45) is set on the fixed block (37), and the base (45) is connected to the internal connecting block (44). Adjusting shafts (38) are arranged on both sides and the upper end of the fixed block (37). One end of the lead screw (35) is fixed to the top plate (34), and the other end is connected to the adjusting shaft (38). A threaded hole is arranged on the adjusting shaft (38), and the lead screw (35) passes through the threaded hole. A connecting shaft (42) is rotatably connected to the fixed block (37), and the connecting shaft (42) is arranged corresponding to the lead screw (35). A second vertical rod (39) is rotatably connected to the adjusting shaft (38), one end of the second vertical rod (39) is connected to the knob (36), and the other end is connected to the first gear (40). One end of the connecting shaft (42) is fixedly connected to the second gear (41), the second gear (41) is located inside the adjusting shaft (38), and the first gear (40) and the second gear (41) are meshed. A spring (43) is connected between the second gear (41) and the end of the lead screw (35). By rotating the knob (36), the top plate (34) presses tightly against the inner side of the steel box girder segment (6) to prevent the steel box girder segment (6) from deforming during the hoisting process; Step 3. Installation of the aerial splicing guide frame (23) for the steel box girder: The aerial splicing guide frame (23) includes an L-shaped bracket (26) and an inclined support (28). Two sleeves (20) are welded to each upper positioning block (31), and one sleeve (20) is welded to each lower positioning block (27). The inclined support (28) is firmly connected to the sleeve (20) through the threads provided at the end; the length of the inclined support (28) is extended through the flange plate (33); a number of positioning grooves (32) are evenly arranged on the L-shaped bracket (26). The upper positioning block (31) and the lower positioning block (27) are respectively placed in the positioning grooves (32) and fixedly connected by bolts; when hoisting the steel box girder segment (6), a guide block (29) is welded to one of the L-shaped brackets (26), and a limiting track (30) is welded to the other L-shaped bracket (26). The cross-section of the guide block (29) is in the shape of a "T", and a slot matching the guide block (29) is provided in the limiting track (30). The two L-shaped brackets (26) are respectively fixed to two adjacent steel box girder segments (6). During hoisting, the guide block (29) on one of the L-shaped brackets (26) is placed in the limiting track (30) of the other L-shaped bracket (26); Step 4. Double-crane hoisting installation of the steel box girder: When hoisting the steel box girder of the overpass ramp, double-crane hoisting is used to smoothly cross the existing ramp, and the two cranes are respectively connected to two lifting rings (16); two pairs of inclined rods (13) are installed on the steel box girder segment (6), a tie rod (14) is welded between each pair of inclined rods (13), and a cross bar (22) is welded between the tops of the two pairs of inclined rods (13); two lifting discs (17) are installed on the cross bar (22), and a lifting ring (16) is welded to the top of the lifting disc (17) for the two cranes to hoist the steel box girder segment (6) respectively; the top of the first vertical rod (19) is connected to the lifting disc (17), and the bottom is fixed to the steel box girder through a sleeve (20); a cross frame (21) is welded between adjacent first vertical rods (19); the steel box girder is hoisted from the middle to both sides, and the two side flange plates (4) are the last to be hoisted; Step 5. Precision positioning construction of the steel box girder segment (6): The height adjustment of the steel box girder segment (6) is achieved through steel pads (7) and jacks (8). The jacks (8) are installed on the first cross beam (3). The steel box girder segment (6) is hoisted and placed on the jacks (8), and the height of the steel box girder segment (6) is adjusted through the jacks (8). Steel pads (7) are arranged between the steel box girder segment (6) and the first cross beam (3); a limiting frame (9) is installed on the first cross beam (3) to conduct rough lateral positioning of the steel box girder segment (6); a lateral precise positioning device is arranged between adjacent steel box girder segments (6); Step 6. Demolition of the steel pipe support system (2): For the support system installed on the concrete foundation (1), two truck cranes are used to demolish it in sections during disassembly; for the demolition construction of the steel pipe support system (2) on the existing steel box girder (12), first, the right-angle connectors (58) are removed, and the entire steel pipe support system (2) is driven by the transport trolley (64) to slide along the guide beam (56) to the end of the guide beam (56), and then the steel pipe support system (2) is hoisted as a whole to the ground and demolished in sections.

2. The construction method of the steel box girder spanning the ramp on the complex support system according to claim 1, characterized in that, In Step 1, a V-shaped support (63) is provided on the upper part of the transport trolley (64), a first anti-falling column (57) is installed on the V-shaped support (63), a second anti-falling column (61) is installed on the second cross beam (10), and a reinforcing steel wire rope (25) is arranged between the first anti-falling column (57) and the second anti-falling column (61).

3. The construction method of the steel box girder spanning the ramp on the complex support system according to claim 1, characterized in that, In Step 5, the transverse precise positioning device includes a sliding track (51), a moving support block (49), and a jack (8). One end of the sliding track (51) is provided with a bottom plate (55), and the bottom plate (55) is placed in a reserved groove (47) provided on the first connecting plate (48), and the bottom plate (55) is fixedly connected to the first connecting plate (48) by bolts; both sides of the moving support block (49) are welded with moving blocks (50), and the moving blocks (50) are placed in the sliding track (51) and can move along the axial direction of the sliding track (51). The other end of the sliding track (51) is provided with a second connecting plate (53), and the second connecting plate (53) is rotatably connected to the sliding track (51) through a rotating shaft (54); a first jack limiting groove (46) and a second jack limiting groove (52) are respectively provided on the moving support block (49) and the second connecting plate (53), and the jack (8) is installed between the moving support block (49) and the second connecting plate (53). The first jack limiting groove (46) and the second jack limiting groove (52) are used to place the two ends of the jack, for precisely positioning the position of the jack (8); after the hoisting of the left and right adjacent steel box girder segments (6) is completed, the assembled transverse precise positioning device is placed on the steel box girder segment (6), and the steel box girder segment (6) is driven to move horizontally through the jack (8), so as to realize the transverse precise positioning of the steel box girder segment (6).

4. A steel box girder spanning a ramp on a complex support system, characterized in that, Obtained by constructing according to the construction method of the complex support system for the overpass ramp steel box girder described in any one of Claims 1 - 3.

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