Construction Method of Existing Box Girder Composite Reinforcement System

Abstract

The present invention relates to a construction method for a combined reinforcement system of existing box girders, including the steps: construction of external prestressed tendons: manhole construction, construction of steel skeleton turning plates, construction of anchor blocks, construction of openings for prestressed tendons, tensioning and anchoring of prestressed tendons; construction of bonding steel plates to the beam body: bonding steel plates inside the beam body, bonding steel plates outside the beam body, bonding steel plates to diaphragms; construction of bonding steel plates to the capping beam for reinforcement: installation of reinforcement steel plates, pressure grouting; construction of replacing the expansion joint: demolition of the original expansion joint structure, installation of the new expansion joint structure. The beneficial effects of the present invention are: effectively reducing the impact of manhole construction on the bottom plate, improving the layout accuracy of external prestressed tendons, enhancing the bonding strength between the bonded steel plates and the beam body, ensuring the installation positioning accuracy of the newly replaced expansion joint structure and the forming effect of the newly poured concrete.

Description

Technical Field

[0001] The present invention belongs to the field of bridge strengthening construction, and particularly relates to a construction method for a combined strengthening system of an in-service box girder. Background Art

[0002] With the increase in the operation time of bridges, various diseases are likely to occur in each structural system of the bridges. In order to improve the operation period of the bridges and ensure the safety of vehicle driving, it is necessary to carry out strengthening operations on the bridges. The existing strengthening methods mainly include setting external prestressing tendons outside the beam body and simultaneously using high-strength materials such as carbon fiber cloth to wrap the surface of the beam body to improve the bearing capacity of the structure. However, there are generally some problems in these construction methods. For example: 1) When opening manholes on the bottom plate of the box girder, the protection of the hole openings is generally not in place, which will cause secondary damage to the bottom plate; 2) When arranging external prestressing tendons, the hole positioning on the deflection plate and the diaphragm beam is inaccurate, resulting in the deviation of the axis of the prestressing tendon from the design; 3) The bonding strength between the steel plates pasted on the surface of the beam body and the beam body is low, and the strengthening effect is not good; 4) After the replacement of the expansion joint structure, the installation accuracy is low, and there are problems such as poor forming effect of the newly poured concrete, low bonding strength with the main beam, and poor durability. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a construction method for a combined strengthening system of an in-service box girder.

[0004] This construction method for a combined strengthening system of an in-service box girder includes the following construction steps:

[0005] S1. Construction of external prestressing tendon strengthening: Construct a manhole on the bottom plate, and fix the strengthening steel cylinder on the bottom plate using a ring locking block; fix the profiled steel skeleton between the bottom plate and the top plate, adjust the height of the guiding sleeve through the sliding wing plate, install and fix the side formwork of the deflection plate on both sides of the profiled steel skeleton using a formwork clamp, and pour the deflection plate of the profiled steel skeleton;

[0006] Pour the anchorage block at the diaphragm at the end of the box girder, and use the hole-opening auxiliary positioning bracket to make the prestressing tendon hole; the external prestressing tendon passes through the guiding sleeve and the prestressing tendon hole, and is anchored at both ends on the anchorage block after tensioning;

[0007] S2. Construction of steel plate bonding on the beam body: Construct and bond steel plates on the surfaces of the bottom plate, top plate and web inside the box girder, and fix them using an internal support frame; hang the hanging operation platform under the wing plate to carry out the construction of bonding steel plates outside the box girder and fix them using an external support frame; bond the steel plates on the surface of the diaphragm and fix them using a U-shaped clamping mechanism;

[0008] S3. Construction of strengthening the bent cap by pasting steel plates: Support the lifting bracket between the box girder and the bent cap, lift the installation operation platform upward to both sides of the bent cap, enclose the bent cap between the bottom reinforcement steel plate and the side reinforcement steel plate, and conduct pressure grouting.

[0009] S4. Construction of replacing the expansion joint.

[0010] Preferably, in step S1, an upper support ring is provided at the upper end of the reinforcement steel cylinder, and a lower support ring is provided at the lower end. The diameter of the lower support ring is larger than the diameter of the opening on the bottom plate, and the diameter of the upper support ring is equal to the diameter of the opening on the bottom plate; the annular locking block is composed of two semi-circular steel rings, its inner diameter is equal to the outer diameter of the reinforcement steel cylinder, and its outer diameter is equal to the outer diameter of the lower support ring. Two layers of annular locking blocks are arranged between the upper support ring and the bottom plate, and the seams of the two layers of annular locking blocks are staggered from each other; a grouting hole is provided on the lower support ring, and micro-expansion cement slurry is injected between the reinforcement steel cylinder and the box girder bottom plate. After the micro-expansion cement slurry reaches the design strength, enter the inside of the box girder from the manhole to conduct the construction of the external prestressed tendons; use expansion bolts to fix the profiled steel skeleton between the bottom plate and the top plate of the box girder. The profiled steel skeleton includes supporting channel steel, fixed end plates, sliding wing plates and guiding sleeves. The fixed end plates are fixed to the bottom plate and the top plate respectively through expansion bolts. The guiding sleeve is arranged on the sliding wing plate, and the sliding wing plate is located in the sliding limit groove on the supporting channel steel; after adjusting the sliding wing plate to adjust the guiding sleeve to the design height, spot-weld the sliding wing plate to the sliding limit groove, and then install the anchoring steel bars according to the steel bar positioning holes on the supporting channel steel; and use the tension tie bolts to pass through the guiding sleeve to fix the side formwork of the steering plate on both sides, and then pour concrete from the pouring hole to complete the pouring operation of the profiled steel skeleton steering plate. After the concrete reaches the design strength, remove the tension tie bolts, formwork clamps and side formwork of the steering plate; rubber cushions are provided on the contact surfaces of the fixed end plates with the top plate and the bottom plate; the surface of the diaphragm is chiseled and roughened before pouring the anchoring block.

[0011] Preferably, in step S1, the opening auxiliary positioning bracket includes a fixed clamp, a drill bit sealing cylinder, a telescopic screw rod I, a drill rod guiding sleeve, a telescopic screw rod II and a supporting screw rod. The fixed clamp, the telescopic screw rod I and the telescopic screw rod II are sleeved on the supporting screw rod through sleeves; the drill bit sealing cylinder is fixed to the upper end of the telescopic screw rod I. One end of the drill rod guiding sleeve is hinged to the drill bit sealing cylinder, and the other end passes out from the upper end of the telescopic screw rod II; the connection part between the drill rod guiding sleeve and the drill bit sealing cylinder is a conical end, and a conical limit nut is provided on the drill rod guiding sleeve; a water inlet hole is provided on the upper side of the drill bit sealing cylinder, and a water outlet hole is provided on the lower side; a sealing ring is provided on the contact surface between the drill bit sealing cylinder and the diaphragm; clamp the opening auxiliary positioning bracket on the lower end of the diaphragm through the fixed clamp thereon, adjust the drill bit sealing cylinder to the designated position through the telescopic screw rod I, adjust the drill rod guiding sleeve to the designated angle through the telescopic screw rod II, pass the drill rod through the drill rod guiding sleeve, and the drill bit is located in the drill bit sealing cylinder to drill the hole for the prestressed tendon.

[0012] Preferably, in the step S2, after the construction of the bonded steel plates for one segment is completed, an external support frame is used to temporarily support and fix the bonded steel plates, and the suspension cables of the first-level working platform are released. Then, it is slid forward along the guiding support channel steel. After sliding to the next working segment, it is re-suspended under the wing plate. Then, the suspension cables of the guiding support channel steel are released, and it is slid forward along the first-level working platform and re-suspended under the wing plate. Then, the bonding of the external bonded steel plates of the beam body, the fixing of the external support frame, and the translation of the hanging working platform are continued in a cycle according to the above steps; the internal support frame includes four symmetrically arranged telescopic rods I and a support plate I. One end of the telescopic rod I is hinged, and the other ends are respectively elastically inserted and connected with the support plate I. A compression spring is provided at the elastic insertion joint of the telescopic rod I and the support plate I. The telescopic rod I of the internal support frame is adjusted to make the support plate I closely adhere to the surface of the bonded steel plate. A first rubber cushion layer is provided on the surface of the support plate I.

[0013] Preferably, in the step S2, the external support frame includes a transverse support section steel, a lateral support section steel, a longitudinal connection section steel, a temporary anchoring cable, a telescopic rod II, and a support plate II. The lateral support section steel is fixed at both ends of the transverse support section steel to form a U-shaped structure. The two ends of the telescopic rod II are respectively hinged to the lateral support section steel and the support plate II. The support plate II closely adheres to the bonded steel plate on the outer side of the web; a support plate II is also provided on the surface of the transverse support section steel, and the support plate II closely adheres to the bonded steel plate on the outer side of the bottom plate. Adjacent transverse support section steels are connected and fixed through the longitudinal connection section steel. One end of the temporary anchoring cable is fixed on the external support frame, and the other end passes through the opening in the wing plate and is anchored on the wing plate; the hanging working platform includes a guiding support channel steel, a suspension cable, a first-level working platform, and a guiding pulley. The guiding support channel steel and the first-level working platform are respectively suspended at the openings in the wing plate through the suspension cable. Support pulleys are provided on both sides of the first-level working platform, and the support pulleys are supported in the guiding support channel steel. A second-level working platform is further provided under the first-level working platform, and the second-level working platform is suspended under the first-level working platform through the suspension cable. An end connection section steel is provided at the end of the guiding support channel steel, and support pulleys and pulley support rods are provided on the side of the working platform; a second rubber cushion layer is provided on the surface of the support plate II.

[0014] Preferably, in the step S2, the U-shaped clamping mechanism includes a screw rod, a telescopic support rod, a telescopic pull rod, and a clamping plate. The telescopic support rod and the telescopic pull rod are installed on the screw rod through a sliding sleeve, and the sliding sleeve is constrained by a limit nut on the screw rod; a foldable telescopic support foot is provided under the U-shaped clamping mechanism, and the telescopic support foot supports on the bottom plate; the lengths of the telescopic support rod and the telescopic pull rod are adjusted to expand the U-shaped clamping mechanism, so that the telescopic support rod, the telescopic pull rod, and the screw rod form a triangle. Then, the sliding sleeves at the lower ends of the telescopic support rod and the telescopic pull rod are constrained by the limit nut, so that the clamping plate clamps the bonded steel plates on both sides of the diaphragm.

[0015] Preferably, in the step S3, the lifting support is provided with a bottom support foot and a top fastening screw. The bottom support foot supports on the capping beam, and the top fastening screw supports on the lower surface of the box girder. The lifting support is also provided with a winch and a steel wire rope; the installation operation platform is provided with a horizontal lateral ejector rod; the installation operation platforms on both sides of the capping beam are symmetrically arranged, and the bottom of the installation operation platform is provided with a connecting steel wire rope to connect and fix the installation operation platforms on both sides; both ends of the bottom reinforcement steel plate are provided with arc-shaped notches that fit the pier column; the upper edge of the side reinforcement steel plate is provided with a strip-shaped flange plate, and the strip-shaped flange plate is placed on the surface of the capping beam; the upper edges of the two side reinforcement steel plates are provided with a connecting steel plate, and the connecting steel plate is welded and fixed to the two side reinforcement steel plates. Rubber sealing strips are provided at the ends of the bottom reinforcement steel plate and the edges of the side reinforcement steel plate; the lifting support is supported between the box girder and the capping beam, and then the weld between the bottom reinforcement steel plate and the side reinforcement steel plate is constructed to wrap the capping beam between the bottom reinforcement steel plate and the side reinforcement steel plate; through the pressure grouting holes on the bottom reinforcement steel plate and the side reinforcement steel plate, a slightly expanding structural adhesive is injected into the gap between the bottom reinforcement steel plate, the side reinforcement steel plate and the capping beam.

[0016] Preferably, in the step S4, first remove the original rubber strip and the middle beam of the original expansion joint, then place the quick cutting device at the expansion joint, adjust the length of the expansion cross beam so that the cutting blade of the cutting machine is located outside the original support box body, adjust the position of the guiding pulley so that it is close to the side wall of the original expansion joint side beam, and finally adjust the height of the cutting blade of the cutting machine through the hydraulic support legs to perform cutting operations on the end of the box girder until the specified depth is cut, then remove the quick cutting device, chisel the concrete at the end of the box girder along the cutting seam, and remove the original expansion joint side beam, the original support longitudinal beam and the original support box body as a whole; the quick cutting device includes an expansion cross beam, a cutting machine, hydraulic support legs, moving pulleys and guiding pulleys. Cutting machines are provided at both ends of the expansion cross beam. A support flat plate is provided between the cutting machine and the expansion cross beam. The expansion cross beam is supported on the moving pulleys through the hydraulic support legs. The moving pulleys are supported on the surface of the box girder. The guiding pulleys are installed on the rotating shafts of the moving pulleys, and the guiding pulleys are supported on the side wall of the original expansion joint side beam.

[0017] Preferably, in step S4, after cutting the original expansion joint structure, stud bolts are installed on the end of the box girder and the support box of the new expansion joint structure. The hanging beam screw is spot-welded and fixed to the side beam of the expansion joint. Then, the gantry installation positioning bracket together with the side beam of the expansion joint, the support longitudinal beam, and the support box are hoisted and placed in place as a whole through the lifting ring. The hydraulic strut is adjusted to make the side formwork closely adhere to the end of the box girder. Then, the hanging beam screw is adjusted to make the end of the support box closely adhere to the side formwork, and the top surface of the side beam of the expansion joint is flush with the surface of the box girder. Then, the anchor bolts are driven into the box girder to fix the gantry installation positioning bracket. Then, high-strength cement mortar is poured between the box girder and the support box. After the high-strength cement mortar reaches the design strength, the gantry installation positioning bracket is removed, and the middle beam of the expansion joint and the rubber strip are installed. The gantry installation positioning bracket is integrally in an inverted U shape, with both ends supported on the box girder. It is provided with hanging beam screws and hanging formwork screws. The lower part of the hanging beam screw is fixed to the side beam of the new expansion joint structure. The lower part of the hanging formwork screw is provided with a hydraulic strut and a side formwork, and the side formwork closely adheres to the ends of the box girder and the support box. The gantry installation positioning bracket is provided with a lifting ring. The two ends of the gantry installation positioning bracket are provided with anchor bolts, and the anchor bolts are implanted into the main beam. The gantry installation positioning bracket is provided with strip-shaped screw holes, and the hanging beam screws pass through the strip-shaped screw holes.

[0018] The existing box girder combined reinforcement system is obtained by any of the above methods.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1) The manhole is reinforced through a reinforced steel cylinder and fixed on the bottom plate using a ring locking block. The structure is simple and reliable, effectively ensuring the reinforcement quality after opening a hole in the bottom plate and ensuring the safety of the structure.

[0021] 2) The profiled steel skeleton structure is simple and reliable, and can be quickly fixed to the top plate and the bottom plate through expansion bolts. The steel bar positioning holes provided on the side can also facilitate the anchoring of the reinforcing steel bars to the side wall of the box girder, ensuring the connection strength between the profiled steel skeleton turning plate and the box girder.

[0022] 3) The position of the guiding sleeve can be accurately adjusted through the sliding wing plate. The opening auxiliary positioning bracket is used for the prestressed tendon opening operation on the diaphragm wall, which can accurately determine the opening position and adjust the axis of the drill rod, effectively ensuring the axis positioning accuracy of the external prestressed tendon, and thus ensuring the reliability of the reinforcement system.

[0023] 4) The bonded steel plates are temporarily fixed through the internal support frame, the external support frame, and the U-shaped clamping mechanism, effectively ensuring the fixing effect of the bonded steel plates, avoiding the situation that the bonded steel plates fall off from the beam body, and effectively ensuring the construction quality of the externally bonded steel plates.

[0024] 5) During the construction of externally bonded steel plates, a suspended working platform is adopted. The working platform is suspended under the wing plate by steel cables and can also slide forward along the guiding support channel steel. After a section of construction is completed, there is no need to lower the entire working platform to the ground and then move it forward, which improves the continuity of construction activities.

[0025] 6) Compared with bonding and fixing with structural adhesive, this technology can achieve the rapid installation and fixing of the reinforcement steel plates. The brackets can be removed without waiting for the injected structural adhesive to solidify and harden, which improves the on-site construction efficiency.

[0026] 7) By using the rapid cutting device proposed in this technology, the rapid cutting and removal of the original expansion joint structure can be achieved, while avoiding damage to the main beam and ensuring the safety of the bridge structure; the new expansion joint structure is temporarily fixed by a gantry installation and positioning bracket, which is simple and reliable. It can not only prevent the displacement of the new expansion joint structure during construction, but also fine-tune the expansion joint structure to ensure the positioning accuracy. Brief Description of the Drawings

[0027] Figure 1 is the construction method flow chart of the existing box girder composite reinforcement system;

[0028] Figure 2 is the structural schematic diagram of the existing box girder composite reinforcement system;

[0029] Figure 3 is the structural schematic diagram of the external prestressed reinforcement system for box girders;

[0030] Figure 4 is the structural schematic diagram of the manhole reinforcement;

[0031] Figure 5 is the semi-sectional view of the three-dimensional structure of the manhole reinforcement;

[0032] Figure 6 is the semi-sectional view of the three-dimensional structure of the reinforcement component;

[0033] Figure 7 is the structural schematic diagram of the annular locking block;

[0034] Figure 8 is the structural schematic diagram of the steel skeleton turning plate restricting the external prestressed tendons;

[0035] Figure 9 is the construction schematic of the steel skeleton turning plate Figure One ;

[0036] Figure 10 is the construction schematic of the steel skeleton turning plate Figure Two ;

[0037] Figure 11 is the three-dimensional structural schematic diagram of the steel skeleton;

[0038] Figure 12 It is a schematic diagram of strengthening the box girder by externally pasting steel plates.

[0039] Figure 13 It is Figure 12 a schematic diagram of temporarily fixing the steel plates pasted on the box girder in the A-A cross-section in

[0040] Figure 14 It is Figure 12 a schematic diagram of the mobile operation platform for externally strengthening the box girder in the B-B cross-section in

[0041] Figure 15 a schematic diagram of the internal support frame structure.

[0042] Figure 16 a schematic diagram of the opening for the prestressed tendons in the box girder diaphragm.

[0043] Figure 17 a schematic diagram of the construction of the opening for the prestressed tendons in the box girder diaphragm.

[0044] Figure 18 a schematic diagram of the auxiliary positioning bracket for the opening.

[0045] Figure 19 a schematic diagram of the steel plates pasted on the box girder diaphragm.

[0046] Figure 20 a schematic diagram of temporarily fixing the steel plates pasted on the box girder diaphragm.

[0047] Figure 21 a schematic diagram of the U-shaped clamping mechanism in the unfolded state.

[0048] Figure 22 a schematic diagram of the U-shaped clamping mechanism in the contracted state.

[0049] Figure 23 a schematic diagram of the construction of strengthening the bent cap by steel casing.

[0050] Figure 24 a schematic diagram of the structure of the operation device for strengthening the bent cap by steel casing.

[0051] Figure 25 a schematic diagram of the steel plate structure for strengthening the bent cap by steel casing.

[0052] Figure 26 a three-dimensional structure schematic diagram of the completed structure of strengthening the bent cap by steel casing.

[0053] Figure 27 a schematic diagram of the original expansion joint structure of the bridge.

[0054] Figure 28 a schematic diagram of the construction of cutting and demolishing the original expansion joint structure of the bridge.

[0055] Figure 29It is a schematic diagram of the installation and positioning of the new bridge expansion joint structure;

[0056] Figure 30 It is a schematic diagram of the installation and concrete pouring of the new bridge expansion joint structure;

[0057] Figure 31 It is Figure 2 A schematic diagram of the installation and positioning of the new bridge expansion joint structure at node A in

[0058] Markings in the figure: 1 - box girder, 11 - top plate, 12 - bottom plate, 13 - diaphragm, 14 - web, 15 - wing plate, 16 - opening in the wing plate, 17 - capping beam, 18 - pier column, 21 - anchorage block, 22 - steel skeleton steering plate, 23 - external prestressing tendon, 24 - opening for prestressing tendon, 25 - bonded steel plate, 31 - manhole, 32 - reinforced steel cylinder, 33 - upper support ring, 34 - lower support ring, 35 - annular locking block, 36 - grouting hole, 37 - slightly expanding cement slurry, 41 - supporting channel steel, 42 - fixed end plate, 43 - expansion bolt, 44 - sliding limit groove, 45 - sliding wing plate, 46 - guiding sleeve, 47 - steel bar positioning hole, 48 - rubber cushion, 51 - anchoring steel bar, 52 - side formwork of the steering plate, 53 - formwork clamp, 54 - tie rod, 55 - pouring hole, 61 - first telescopic rod, 62 - first support plate, 63 - first rubber cushion, 64 - compression spring, 71 - transverse supporting section steel, 72 - lateral supporting section steel, 73 - longitudinal connecting section steel, 74 - temporary anchorage steel cable, 75 - second telescopic rod, 76 - second support plate, 77 - second rubber cushion, 81 - guiding support channel steel, 82 - end connecting section steel, 83 - suspension steel cable, 84 - first-level operation platform, 85 - guiding pulley, 86 - supporting pulley, 87 - pulley support rod, 88 - second-level operation platform, 91 - fixed clamp, 92 - drill bit sealing cylinder, 93 - water inlet hole, 94 - water outlet hole, 95 - sealing ring, 96 - first telescopic screw, 97 - drill pipe guiding sleeve, 98 - tapered end, 99 - tapered limit nut, 910 - second telescopic screw, 911 - supporting screw, 101 - drill pipe, 102 - drill bit, 111 - screw, 112 - sliding sleeve, 113 - limit nut, 114 - telescopic support rod, 115 - telescopic pull rod, 116 - clamping plate, 117 - telescopic support foot, 121 - bottom reinforcement steel plate, 122 - side reinforcement steel plate, 123 - strip-shaped flange plate, 124 - weld, 125 - connecting steel plate, 126 - pressure grouting hole, 127 - rubber sealing strip, 131 - lifting support, 132 - bottom support foot, 133 - top fastening screw, 134 - winch, 135 - steel wire rope, 141 - installation operation platform, 142 - lateral ejector rod, 143 - connecting steel wire rope, 151 - original rubber strip, 152 - original middle beam of expansion joint, 153 - original side beam of expansion joint, 154 - original supporting longitudinal beam, 155 - original supporting box body, 161 - expansion cross beam, 162 - support flat plate, 163 - cutting machine, 164 - hydraulic support leg, 165 - moving pulley, 166 - rotating shaft, 167 - limit pulley, 171 - portal installation positioning support, 172 - lifting ring, 173 - hanging beam screw, 174 - strip-shaped screw hole, 175 - formwork hanging screw, 176 - side formwork, 177 - hydraulic support rod, 178 - anchor bolt, 181 - rubber strip, 182 - middle beam of expansion joint, 183 - side beam of expansion joint, 184 - supporting longitudinal beam, 185 - supporting box body, 186 - stud, 187 - high-strength cement mortar. Detailed implementation manners

[0059] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0060] Embodiment 1

[0061] As an embodiment, as Figure 1 shown, a construction method for a combined reinforcement system of existing box girders is proposed, which effectively guarantees the reinforcement quality, improves the reinforcement construction efficiency, and ensures the safety of operators. To achieve the purpose, the technical solution provided by the present invention includes the following construction steps:

[0062] S1. Construction of external prestressed tendon 23 for reinforcement

[0063] S1.1. Construction of manhole 31: A manhole 31 is constructed by drilling a hole in the bottom plate 12 of the box girder 1. Then, a reinforcement steel cylinder 32 is installed in the drilled hole, and the reinforcement steel cylinder 32 is fixed to the bottom plate 12 using a ring locking block 35. Micro-expansion cement slurry 37 is injected between the reinforcement steel cylinder 32 and the bottom plate 12 of the box girder 1. After the micro-expansion cement slurry 37 reaches the design strength, operators can enter the interior of the box girder 1 through the manhole 31 to perform the construction of the external prestressed tendon 23 for reinforcement; an upper support ring 33 is provided at the upper end of the reinforcement steel cylinder 32, and a lower support ring 34 is provided at the lower end. The diameter of the lower support ring 34 is larger than the diameter of the hole drilled in the bottom plate 12, and the diameter of the upper support ring 33 is equal to the diameter of the hole drilled in the bottom plate 12, ensuring that the upper end of the reinforcement steel cylinder 32 can be smoothly inserted into the bottom plate 12; the ring locking block 35 is composed of two semi-circular steel rings, the inner diameter of which is equal to the outer diameter of the reinforcement steel cylinder 32, and the outer diameter of which is equal to the outer diameter of the lower support ring 34. Two layers of ring locking blocks 35 are provided between the upper support ring 33 and the bottom plate 12, and the joints of the two layers of ring locking blocks 35 are staggered from each other. By setting the ring locking block 35, the reinforcement steel cylinder 32 is firmly fixed to the bottom plate 12; a grouting hole 36 is provided on the lower support ring 34, and the micro-expansion cement slurry 37 is injected into the gap between the reinforcement steel cylinder 32 and the bottom plate 12 through the grouting hole 36. By injecting the micro-expansion cement slurry 37, the reinforcement steel cylinder 32 and the bottom plate 12 are firmly connected together, ensuring the safety of the bottom plate 12 and the structure of the manhole 31.

[0064] S1.2, Construction of the profiled steel skeleton steering plate 22: Fix the profiled steel skeleton between the bottom plate 12 and the top plate 11 of the box girder 1 using expansion bolts 43. Then, adjust the sliding wing plate 45 to adjust the guiding sleeve 46 to the designed height, and then spot-weld the sliding wing plate 45 to the sliding limit groove 44. Then, install the anchoring steel bars 51 according to the steel bar positioning holes 47 on the supporting channel steel 41 to form a steel bar skeleton. After the anchoring steel bars 51 are installed in place, use the form clamp 53 to install and fix the side formwork 52 of the steering plate on both sides of the profiled steel skeleton, and use the tension rod 54 to pass through the guiding sleeve 46 to further fix the side formwork 52 of the steering plate on both sides. Then, pour concrete into the pouring hole 55 to complete the pouring operation of the profiled steel skeleton steering plate 22. After the concrete reaches the designed strength, remove the tension rod 54, the form clamp 53, and the side formwork 52 of the steering plate to complete the pouring operation of the profiled steel skeleton steering plate 22; The profiled steel skeleton includes the supporting channel steel 41, the fixed end plate 42, the sliding wing plate 45, and the guiding sleeve 46. The fixed end plate 42 is fixed to the bottom plate 12 and the top plate 11 respectively through expansion bolts 43 to enhance the connection strength between the profiled steel skeleton steering plate 22 and the bottom plate 12 and the top plate 11. The guiding sleeve 46 is arranged on the sliding wing plate 45, and the sliding wing plate 45 is located in the sliding limit groove 44 on the supporting channel steel 41. The sliding wing plate 45 can move along the sliding limit groove 44 to adjust the position of the guiding sleeve 46 thereon to ensure the accurate positioning of the guiding sleeve 46; The contact surfaces of the fixed end plate 42 with the top plate 11 and the bottom plate 12 are provided with rubber cushions 48. By setting the rubber cushions 48, the sealing performance between the fixed end plate 42 and the top plate 11 and the bottom plate 12 is enhanced to avoid the leakage of the internal concrete during the pouring of the profiled steel skeleton steering plate 22.

[0065] S1.3, Construction of the anchoring block: Pour the anchoring block 21 closely against the diaphragm 13 at the end of the box girder 1. Before pouring the anchoring block 21, roughen the surface of the diaphragm 13.

[0066] S1.4, Construction of the prestressed tendon opening 24: Clamp the opening auxiliary positioning bracket on the lower end of the diaphragm 13 through the fixing clip 91 thereon. Adjust the drill bit sealing cylinder 92 to the designated position through the first telescopic screw 96, and adjust the drill pipe guiding sleeve 97 to the designated angle through the second telescopic screw 910. The drill pipe 101 passes through the drill pipe guiding sleeve 97, and the drill bit 102 is located inside the drill bit sealing cylinder 92 to construct the prestressed tendon opening 24. The opening auxiliary positioning bracket includes a fixing clip 91, a drill bit sealing cylinder 92, a first telescopic screw 96, a drill pipe guiding sleeve 97, a second telescopic screw 910, and a support screw 911. The fixing clip 91, the first telescopic screw 96, and the second telescopic screw 910 are sleeved on the support screw 911 through sleeves, can move along the support screw 911, and are restricted from moving by the nuts on the support screw 911. The drill bit sealing cylinder 92 is fixed to the upper end of the first telescopic screw 96, and the drill bit sealing cylinder 92 is supported and fixed by the first telescopic screw 96. One end of the drill pipe guiding sleeve 97 is hinged to the drill bit sealing cylinder 92, and the other end passes through the upper end of the second telescopic screw 910, and the drill pipe guiding sleeve 97 is supported and fixed by the second telescopic screw 910. The fixing clip 91 is clamped on the lower end of the diaphragm 13, and the drill bit sealing cylinder 92 is closely attached to the surface of the diaphragm 13. The connection between the drill pipe guiding sleeve 97 and the drill bit sealing cylinder 92 is a tapered end 98, and a tapered limit nut 99 is provided on the drill pipe guiding sleeve 97 to ensure that the drill pipe guiding sleeve 97 can rotate freely relative to the drill bit sealing cylinder 92 for adjusting and fixing the axis of the drill pipe guiding sleeve 97. A water inlet hole 93 is provided on the upper side of the drill bit sealing cylinder 92, and a water outlet hole 94 is provided on the lower side, which can reduce dust when constructing the prestressed tendon opening 24. A sealing ring 95 is provided on the contact surface between the drill bit sealing cylinder 92 and the diaphragm 13 to prevent the introduced cooling water from flowing disorderly.

[0067] S1.5, Tensioning and anchoring of the prestressed tendon: Pass the external prestressed tendon 23 through the guiding sleeve 46 on the steel skeleton turning plate 22 and the prestressed tendon opening 24 on the diaphragm 13, tension the external prestressed tendon 23, and then anchor both ends of the external prestressed tendon 23 on the anchor block 21.

[0068] S2, Construction of bonding steel plates 25 on the beam body

[0069] S2.1. Inner steel plate pasting on the beam body: Enter the inner part of the beam body to construct and paste the steel plate 25 on the surfaces of the bottom plate 12, the top plate 11, and the web 14, and use the internal support frame to temporarily fix the steel plate 25 inside the beam body. Adjust the telescopic rod 61 of the internal support frame to make the support plate 62 closely adhere to the surface of the steel plate 25. The internal support frame includes four symmetrically arranged telescopic rods 61 and a support plate 62. One end of the telescopic rod 61 is hinged, and the other end is elastically inserted and connected to the support plate 62. A compression spring 64 is provided at the elastic insertion part of the telescopic rod 61 and the support plate 62. By setting the compression spring 64, it is ensured that the internal support frame firmly supports the steel plate 25 and avoids uneven local stress. A rubber cushion 63 is provided on the surface of the support plate 62, and a rubber cushion 77 is provided on the surface of the support plate 76. By setting rubber cushions on the support plates, it is ensured that the support plates are closely attached to the steel plate 25.

[0070] S2.2. Outer steel plate pasting on the beam body: First, construct the wing plate opening 16 on the wing plate 15, and then suspend the guiding support channel steel 81 and the first-level working platform 84 of the hanging working platform under the wing plate 15 through the suspension steel cables 83 respectively. Relying on the hanging working platform, construct the outer steel plate 25 pasting on the beam body. After the construction of the steel plate 25 for one segment is completed, use the external support frame to temporarily support and fix the steel plate 25, and release the suspension steel cable 83 of the first-level working platform 84. Then slide it forward along the guiding support channel steel 81. After sliding to the next working segment, re-suspend it under the wing plate 15. Then release the suspension steel cable 83 of the guiding support channel steel 81, slide it forward along the first-level working platform 84, and re-suspend it under the wing plate 15. Then continue to cycle through the above steps for the pasting, temporary support and fixation of the outer steel plate 25 on the beam body and the translation of the hanging working platform. The external support frame includes a transverse support section steel 71, a lateral support section steel 72, a longitudinal connection section steel 73, a temporary anchoring steel cable 74, a telescopic rod 75, and a support plate 76. The lateral support section steel 72 is fixed at both ends of the transverse support section steel 71 to form a U-shaped structure. Both ends of the telescopic rod 75 are hinged to the lateral support section steel 72 and the support plate 76 respectively. The support plate 76 closely adheres to the steel plate 25 outside the web 14. The support plate 76 is also provided on the surface of the transverse support section steel 71, and the support plate 76 closely adheres to the steel plate 25 outside the bottom plate 12. The adjacent transverse support section steels 71 are connected and fixed by the longitudinal connection section steel 73. One end of the temporary anchoring steel cable 74 is fixed on the external support frame, and the other end passes through the wing plate opening 16 and is anchored on the wing plate 15.

[0071] The suspended working platform includes a guiding and supporting channel steel 81, a suspension steel cable 83, a primary working platform 84, and a guiding pulley 85. The guiding and supporting channel steel 81 and the primary working platform 84 are respectively suspended at the wing plate opening 16 through the suspension steel cable 83. Support pulleys 86 are arranged on both sides of the primary working platform 84, and the support pulleys 86 are supported inside the guiding and supporting channel steel 81. A secondary working platform 88 can also be added below the primary working platform 84. The secondary working platform 88 is suspended below the primary working platform 84 through the suspension steel cable 83. An end connecting section steel 82 is provided at the end of the guiding and supporting channel steel 81 to connect two guiding and supporting channel steels 81 into a whole. Support pulleys 86 and pulley support rods 87 are arranged on the side of the working platform. By adjusting the length of the pulley support rod, the support pulley 86 is made to closely adhere to the surface of the web 14, improving the stability of the working platform during construction.

[0072] S2.3, Bonding steel plates to the diaphragm: Process a U-shaped bonding steel plate 25 according to the size of the diaphragm 13, then bond it to the surface of the diaphragm 13, and use a U-shaped clamping mechanism for temporary support and fixation; Adjust the lengths of the telescopic support rod 114 and the telescopic pull rod 115 to expand the U-shaped clamping mechanism, so that the telescopic support rod 114, the telescopic pull rod 115, and the screw rod 111 form a triangle, and then use the limit nut 113 to restrict the sliding sleeves 112 at the lower ends of the telescopic support rod 114 and the telescopic pull rod 115, so that the clamping plates 116 clamp the bonding steel plates 25 on both sides of the diaphragm 13; The U-shaped clamping mechanism includes a screw rod 111, a telescopic support rod 114, a telescopic pull rod 115, and clamping plates 116. The telescopic support rod 114 and the telescopic pull rod 115 are installed on the screw rod 111 through the sliding sleeves 112, and the sliding sleeves 112 are restricted by the limit nut 113 on the screw rod 111. The telescopic support rod 114, the telescopic pull rod 115, and the screw rod 111 form a triangular structure, and the clamping plate 116 at one corner of the triangle closely adheres to the bonding steel plate 25; A foldable telescopic support foot 117 is provided below the U-shaped clamping mechanism, and the telescopic support foot 117 is supported on the bottom plate 12 to prevent the U-shaped clamping mechanism from falling off the diaphragm 13; Since the space between the bottom plate 12 and the top plate 11 of the box girder 1 is narrow, the U-shaped clamping mechanism is designed to be foldable to ensure that it can be smoothly transported into the interior of the box girder 1.

[0073] S3, Construction of strengthening the cover beam 17 by bonding steel plates

[0074] S3.1, Installation of the strengthening steel plates: Support the lifting bracket 131 between the box girder 1 and the cover beam 17. Place the bottom strengthening steel plate 121 and the side strengthening steel plate 122 of the cover beam 17 on the installation working platform 141. Lift the installation working platform 141 upward through the lifting bracket 131 to both sides of the cover beam 17, and then weld the weld 124 between the bottom strengthening steel plate 121 and the side strengthening steel plate 122 to wrap the cover beam 17 between the bottom strengthening steel plate 121 and the side strengthening steel plate 122;

[0075] S3.2, Pressure grouting: Through the pressure grouting holes 126 on the bottom reinforcement steel plate 121 and the side reinforcement steel plate 122, inject micro-expansive structural adhesive into the gap between the reinforcement steel plate and the capping beam 17; The lifting support 131 is provided with a bottom support foot 132 and a top fastening screw 133. The bottom support foot 132 supports on the capping beam 17, and the top fastening screw 133 supports on the lower surface of the box girder 1. The structure is simple and reliable. By using the self-weight of the box girder 1, it can effectively prevent the lifting support 131 from displacing and tipping over. The lifting support 131 is also provided with a winch 134 and a steel wire rope 135, and the installation operation platform 141 is lifted through the winch 134 and the steel wire rope 135; The installation operation platform 141 is provided with a horizontal lateral ejector rod 142, and the lateral ejector rod 142 is used to temporarily resist the side reinforcement steel plate 122 to facilitate the welding seam 124 between the bottom reinforcement steel plate 121 and the side reinforcement steel plate 122; The installation operation platforms 141 on both sides of the capping beam 17 are symmetrically arranged. The bottom of the installation operation platform 141 is provided with a connecting steel wire rope 143 to connect and fix the installation operation platforms 141 on both sides, preventing the installation operation platform 141 from being lifted and displaced by the thrust of the lateral ejector rod 142; Both ends of the bottom reinforcement steel plate 121 are provided with arc-shaped notches that fit the pier column 18; The upper edge of the side reinforcement steel plate 122 is provided with a strip-shaped flange plate 123, and the strip-shaped flange plate 123 is placed on the surface of the capping beam 17 to achieve rapid installation operation of the side reinforcement steel plate 122, reduce the installation difficulty, and at the same time improve the bending resistance of the side reinforcement steel plate 122; The upper edges of the two side reinforcement steel plates 122 are provided with a connecting steel plate 125, and the connecting steel plate 125 is welded and fixed to the two side reinforcement steel plates 122 to achieve rapid fixation of the side reinforcement steel plates 122, and at the same time prevent the side reinforcement steel plates 122 from being lifted and deformed by the micro-expansive structural adhesive, affecting the reinforcement effect. The ends of the bottom reinforcement steel plate 121 and the edges of the side reinforcement steel plates 122 are provided with rubber sealing strips 127 to prevent the injected micro-expansive structural adhesive from overflowing.

[0076] S4, Construction of replacing the expansion joint

[0077] S4.1. Demolition of the original expansion joint structure: First, remove the original rubber strip 151 and the original expansion joint middle beam 152. Then, place the rapid cutting device at the expansion joint, adjust the length of the telescopic cross beam 161 so that the cutting blade of the cutting machine is located outside the original support box 155, adjust the position of the limit pulley 167 so that it closely adheres to the side wall of the original expansion joint side beam 153. Finally, adjust the height of the cutting blade of the cutting machine through the hydraulic support leg 164 to perform cutting operations on the end of the box girder 1 until the specified depth is cut. Then, remove the rapid cutting device, chisel the concrete at the end of the box girder 1 along the cutting seam, and demolish the original expansion joint side beam 153, the original support longitudinal beam 154, and the original support box 155 as a whole; The rapid cutting device includes a telescopic cross beam 161, a cutting machine 163, a hydraulic support leg 164, a moving pulley 165, and a limit pulley 167. Cutting machines 163 are provided at both ends of the telescopic cross beam 161. A support flat plate 162 is provided between the cutting machine 163 and the telescopic cross beam 161. The telescopic cross beam 161 is supported on the moving pulley 165 through the hydraulic support leg 164. The moving pulley 165 is supported on the surface of the box girder 1. The limit pulley 167 is installed on the rotating shaft 166 of the moving pulley 165, and the limit pulley 167 is supported on the side wall of the original expansion joint side beam 153.

[0078] S4.2. Installation of the new expansion joint structure: First, install stud 186 on the end of box girder 1 and the support box 185 of the new expansion joint structure. Spot-weld the lifting beam screw 173 to the expansion joint side beam 183. Then, use the lifting ring 172 to hoist the gantry installation positioning bracket 171 together with the expansion joint side beam 183, support longitudinal beam 184, and support box 185 into place. Adjust the hydraulic strut 177 to make the side form 176 closely adhere to the end of box girder 1. Then, adjust the lifting beam screw 173 to make the end of the support box 185 closely adhere to the side form 176, and the top surface of the expansion joint side beam 183 is flush with the surface of box girder 1. Next, drive the anchor bolt 178 into box girder 1 to fix the gantry installation positioning bracket 171. Then, pour high-strength cement mortar 187 between box girder 1 and the support box 185. After the high-strength cement mortar 187 reaches the design strength, remove the gantry installation positioning bracket 171, and install the expansion joint middle beam 182 and rubber strip 181. The gantry installation positioning bracket 171 is integrally in an inverted U shape, with both ends supported on box girder 1. It is provided with a lifting beam screw 173 and a formwork lifting screw 175. The lower part of the lifting beam screw 173 is fixed to the expansion joint side beam 183 of the new expansion joint structure. The lower part of the formwork lifting screw 175 is provided with a hydraulic strut 177 and a side form 176. The side form 176 closely adheres to the ends of box girder 1 and the support box 185 to prevent mortar leakage from the end of box girder 1 when pouring high-strength cement mortar 187. The gantry installation positioning bracket 171 is provided with a lifting ring 172, which is convenient for lifting and placing the gantry installation positioning bracket 171 and the new expansion joint structure as a whole. The two ends of the gantry installation positioning bracket 171 are provided with anchor bolts 178, and the anchor bolts 178 are implanted into box girder 1 to temporarily fix the gantry installation positioning bracket 171 through the anchor bolts 178 to prevent the gantry installation positioning bracket 171 from shifting during construction. The gantry installation positioning bracket 171 is provided with a strip-shaped screw hole 174, and the lifting beam screw 173 passes through the strip-shaped screw hole 174, which is convenient for fine-tuning the position of the new expansion joint structure.

[0079] Embodiment 2

[0080] As another embodiment, as Figures 2 to 31 shown, the existing box girder combined reinforcement system obtained by the method proposed in Embodiment 1 includes an external prestressed reinforcement system for box girder, a steel plate bonding reinforcement structure for box girder, a steel plate bonding reinforcement structure for box girder diaphragm, a steel plate bonding reinforcement structure for cap beam, and a new structure for replacing bridge expansion joint.

[0081] The external prestressed reinforcement system for the box girder includes a manhole 31 opened on the bottom plate 12 of the box girder 1, a steel skeleton turning plate 22 located between the bottom plate 12 and the top plate 11, an anchor block 21 arranged on the diaphragm 13, and external prestressed tendons 23 passing through the inside of the box girder 1; a reinforcement steel cylinder 32 is provided at the edge of the manhole 31, and the reinforcement steel cylinder 32 is fixed on the bottom plate 12 through an annular locking block 35, and a slightly expanding cement slurry 37 is injected between the reinforcement steel cylinder 32 and the bottom plate 12; a steel skeleton is cast on the side of the steel skeleton turning plate 22, and the steel skeleton includes a support channel steel 41, a fixed end plate 42, a sliding wing plate 45, and a guiding sleeve 46. The fixed end plate 42 is fixed to the bottom plate 12 and the top plate 11 respectively through expansion bolts 43 to enhance the connection strength between the steel skeleton turning plate 22 and the bottom plate 12 and the top plate 11. The guiding sleeve 46 is arranged on the sliding wing plate 45, and the sliding wing plate 45 is located in the sliding limit groove 44 on the support channel steel 41. The sliding wing plate 45 can move along the sliding limit groove 44 to adjust the position of the guiding sleeve 46 thereon and ensure the accurate positioning of the guiding sleeve 46; both ends of the external prestressed tendon 23 are anchored on the anchor block 21, and the external prestressed tendon 23 passes through the guiding sleeve 46 on the steel skeleton turning plate 22.

[0082] An upper support ring 33 is provided at the upper end of the reinforcement steel cylinder 32, and a lower support ring 34 is provided at the lower end. The diameter of the lower support ring 34 is larger than the diameter of the opening on the bottom plate 12, and the diameter of the upper support ring 33 is equal to the diameter of the opening on the bottom plate 12 to ensure that the upper end of the reinforcement steel cylinder 32 can be smoothly inserted into the bottom plate 12; the annular locking block 35 is composed of two semi-circular steel rings, its inner diameter is equal to the outer diameter of the reinforcement steel cylinder 32, and its outer diameter is equal to the outer diameter of the lower support ring 34. Two layers of annular locking blocks 35 are arranged between the upper support ring 33 and the bottom plate 12, and the seams of the two layers of annular locking blocks 35 are staggered from each other. By setting the annular locking block 35, the reinforcement steel cylinder 32 is firmly fixed on the bottom plate 12.

[0083] A grouting hole 36 is provided on the lower support ring 34, and the slightly expanding cement slurry 37 is injected into the gap between the reinforcement steel cylinder 32 and the bottom plate 12 through the grouting hole 36. By injecting the slightly expanding cement slurry 37, it is ensured that the reinforcement steel cylinder 32 and the bottom plate 12 are firmly connected together to ensure the safety of the structure of the bottom plate 12 and the manhole 31.

[0084] Reinforcement bar positioning holes 47 are provided on the support channel steel 41 to assist in the installation and positioning of the anchoring reinforcement bars 51 inside the steel skeleton turning plate 22 and reduce the on-site operation difficulty.

[0085] Rubber cushion layers 48 are provided on the contact surfaces of the fixed end plate 42 with the top plate 11 and the bottom plate 12. By setting the rubber cushion layers 48, the sealing performance between the fixed end plate 42 and the top plate 11 and the bottom plate 12 is improved, and the leakage of the internal concrete during the casting of the steel skeleton turning plate 22 is avoided.

[0086] The box girder steel plate bonding reinforcement structure includes a steel plate 25 bonded to the surface of the box girder 1, an in - body support frame for fixing the steel plate 25 inside the box girder 1, an out - of - body support frame for fixing the steel plate 25 outside the box girder 1, and a hanging working platform for constructing the steel plate 25 outside. The in - body support frame includes four symmetrically arranged telescopic rods one 61 and a support plate one 62. One end of the telescopic rod one 61 is hinged, and the other end is elastically inserted and connected to the support plate one 62. The support plate one 62 closely adheres to the steel plate 25 on the surfaces of the top plate 11, the bottom plate 12, and the web 14.

[0087] The out - of - body support frame includes a transverse support section steel 71, a lateral support section steel 72, a longitudinal connection section steel 73, a temporary anchoring steel cable 74, a telescopic rod two 75, and a support plate two 76. The lateral support section steel 72 is fixed at both ends of the transverse support section steel 71 to form a U - shaped structure. Both ends of the telescopic rod two 75 are hinged to the lateral support section steel 72 and the support plate two 76 respectively. The support plate two 76 closely adheres to the steel plate 25 outside the web 14. The surface of the transverse support section steel 71 is also provided with a support plate two 76, and the support plate two 76 closely adheres to the steel plate 25 outside the bottom plate 12. Adjacent transverse support section steels 71 are connected and fixed by the longitudinal connection section steel 73. One end of the temporary anchoring steel cable 74 is fixed to the out - of - body support frame, and the other end is anchored to the wing plate 15.

[0088] The hanging working platform includes a guiding support channel steel 81, a suspension steel cable 83, a primary working platform 84, and a guiding pulley 85. The guiding support channel steel 81 and the primary working platform 84 are respectively suspended below the wing plate 15 by the suspension steel cable 83. Support pulleys 86 are arranged on both sides of the primary working platform 84, and the support pulleys 86 are supported inside the guiding support channel steel 81. A secondary working platform 88 can be additionally arranged below the primary working platform 84, and the secondary working platform 88 is suspended below the primary working platform 84 by the suspension steel cable 83. The guiding support channel steel 81 and the primary working platform 84 are respectively suspended below the wing plate 15 by the suspension steel cable 83. Support pulleys 86 are arranged on both sides of the primary working platform 84, and the support pulleys 86 are supported inside the guiding support channel steel 81. A secondary working platform 88 is arranged below the primary working platform 84, and the secondary working platform 88 is suspended below the primary working platform 84 by the suspension steel cable 83. The structures of the secondary working platform 88 and the primary working platform 84 are the same. Support pulleys 86 are arranged on both sides of the secondary working platform 88, and the support pulleys 86 are supported inside the guiding support channel steel 81. Support pulleys 86 and pulley support rods 87 are arranged on the side edges of the secondary working platform 88 and the primary working platform 84 close to the web 14.

[0089] A compression spring 64 is arranged at the elastic insertion part of the telescopic rod one 61 and the support plate one 62. By arranging the compression spring 64, it is ensured that the in - body support frame firmly supports the steel plate 25 and avoids uneven local stress.

[0090] A rubber cushion layer I (63) is provided on the surface of the first support plate (62), and a rubber cushion layer II (77) is provided on the surface of the second support plate (76), ensuring that the support plates are in close contact with the bonded steel plates (25).

[0091] The wing plate (15) is provided with wing plate openings (16), and both the temporary anchoring steel cable (74) and the suspension steel cable (83) can pass through the wing plate openings (16) and be anchored on the wing plate (15).

[0092] The end of the guiding support channel steel (81) is provided with an end connecting section steel (82) to connect two guiding support channel steels (81) into a whole. Support pulleys (86) and pulley support rods (87) are provided on the side of the working platform. By adjusting the length of the pulley support rod (87), the support pulley (86) is made to closely adhere to the surface of the web (14), improving the stability of the working platform during construction.

[0093] The bonded steel plate reinforcement structure for the box girder diaphragm includes the bonded steel plates (25) and prestressed tendon openings (24) on the diaphragm (13), an auxiliary positioning bracket for the diaphragm opening, and a U-shaped clamping mechanism for temporarily fixing the bonded steel plates (25). The bonded steel plates (25) are bonded on both sides of the diaphragm (13). The vertical bonded steel plates (25) are of U-shaped structure. The U-shaped structure can improve the integrity of the bonded steel plates (25), clamp the diaphragm (13) inside the U-shaped structure, and improve the reinforcement strength of the diaphragm (13).

[0094] The auxiliary positioning bracket for the opening includes a fixed clamp (91), a drill bit sealing cylinder (92), a first telescopic screw rod (96), a drill rod guiding sleeve (97), a second telescopic screw rod (910), and a support screw rod (911). The fixed clamp (91), the first telescopic screw rod (96), and the second telescopic screw rod (910) are sleeved on the support screw rod (911) through sleeves, can move along the support screw rod (911), and are restricted from moving by the nuts on the support screw rod (911).

[0095] The drill bit sealing cylinder (92) is fixed to the upper end of the first telescopic screw rod (96), and the drill bit sealing cylinder (92) is supported and fixed by the first telescopic screw rod (96). One end of the drill rod guiding sleeve (97) is hinged to the drill bit sealing cylinder (92), and the other end passes out from the upper end of the second telescopic screw rod (910), and the drill rod guiding sleeve (97) is supported and fixed by the second telescopic screw rod (910).

[0096] The fixed clamp 91 is clamped at the lower end of the diaphragm 13, the drill bit sealing cylinder 92 is closely attached to the surface of the diaphragm 13, the drill pipe 101 passes through the guiding sleeve 97 of the drill pipe 101, and the drill bit 102 is located inside the drill bit sealing cylinder 92 to make the opening 24 for the prestressed tendon; The U-shaped clamping mechanism includes a screw rod 111, a telescopic strut 114, a telescopic tie rod 115, and a clamping plate 116. The telescopic strut 114 and the telescopic tie rod 115 are installed on the screw rod 111 through a sliding sleeve 112, and the sliding sleeve 112 is restricted by a limit nut 113 on the screw rod 111. The telescopic strut 114, the telescopic tie rod 115, and the screw rod 111 form a triangular structure, and the clamping plate 116 at one corner of the triangle is closely attached to the bonding steel plate 25. A limit nut 113 is also provided on the screw rod 111, and the sliding sleeve 112 is fixed by the limit nut 113 on the screw rod 111. The bottom ends of the telescopic strut 114 and the telescopic tie rod 115 are hinged to the sliding sleeve 112.

[0097] The upper side of the drill bit sealing cylinder 92 is provided with a water inlet hole 93, and the lower side is provided with a water outlet hole 94, which can reduce dust when making the opening 24 for the prestressed tendon; A sealing ring 95 is provided on the contact surface between the drill bit sealing cylinder 92 and the diaphragm 13 to prevent the introduced cooling water from flowing disorderly.

[0098] The connection part between the drill pipe guiding sleeve 97 and the drill bit sealing cylinder 92 is a tapered end 98, and a tapered limit nut 99 is provided on the drill pipe guiding sleeve 97 to ensure that the drill pipe guiding sleeve 97 can rotate freely relative to the drill bit sealing cylinder 92, so as to adjust and fix the axis of the drill pipe guiding sleeve 97.

[0099] A foldable telescopic support foot 117 is provided below the U-shaped clamping mechanism, and the telescopic support foot 117 supports on the bottom plate 12 to prevent the U-shaped clamping mechanism from falling off the diaphragm 13; Since the space between the bottom plate 12 and the top plate 11 of the box girder 1 is narrow, the U-shaped clamping mechanism is designed to be foldable to ensure that it can be smoothly transported into the interior of the box girder 1.

[0100] The cap beam bonding steel plate reinforcement structure includes a bottom reinforcement steel plate 121, a side reinforcement steel plate 122, a lifting bracket 131, and an installation operation platform 141. The lifting bracket 131 supports between the main beam and the cap beam 17; The installation operation platform 141 is hung on both sides of the cap beam 17 through the lifting bracket 131. The bottom reinforcement steel plate 121 and the side reinforcement steel plate 122 are lifted to the specified installation height through the installation operation platform 141, and the installation operation of the reinforcement steel plate is carried out; The bottom reinforcement steel plate 121 is closely attached to the lower surface of the cap beam 17, the side reinforcement steel plate 122 is closely attached to the side of the cap beam 17, the bottom reinforcement steel plate 121 and the side reinforcement steel plate 122 are welded and connected, and a slightly expanded structural adhesive is injected between the reinforcement steel plate and the cap beam 17 to form a firm whole between the reinforcement steel plate and the cap beam 17.

[0101] The lifting support 131 is provided with a bottom support leg 132 and a top fastening screw 133. The bottom support leg 132 supports on the capping beam 17, and the top fastening screw 133 supports on the lower surface of the main beam. The structure is simple and reliable. By utilizing the dead weight of the main beam, the displacement and rollover of the lifting support 131 can be effectively avoided. The lifting support 131 is also provided with a winch 134 and a steel wire rope 135, and the installation operation platform 141 is lifted by the winch 134 and the steel wire rope 135.

[0102] The installation operation platform 141 is provided with a horizontal lateral ejector rod 142, and the lateral ejector rod 142 is temporarily abutted against the side reinforcement steel plate 122 to facilitate the construction of the weld 124 between the bottom reinforcement steel plate 121 and the side reinforcement steel plate 122; the installation operation platforms 141 on both sides of the capping beam 17 are symmetrically arranged, and a connecting steel wire rope 143 is arranged at the bottom of the installation operation platform 141 to connect and fix the installation operation platforms 141 on both sides, so as to prevent the installation operation platform 141 from being lifted and displaced by the thrust of the lateral ejector rod 142. The lateral ejector rod 142 is propped against the side reinforcement steel plates 122 on both sides of the capping beam 17.

[0103] The bottom reinforcement steel plate 121 and the side reinforcement steel plate 122 are both provided with grouting holes 36, and the slightly expanding structural adhesive is injected into the gap between the reinforcement steel plate and the capping beam 17 from the grouting holes 36. Rubber sealing strips 127 are arranged at the ends of the bottom reinforcement steel plate 121 and the edges of the side reinforcement steel plates 122 to prevent the injected slightly expanding structural adhesive from overflowing.

[0104] Both ends of the bottom reinforcement steel plate 121 are provided with arc-shaped notches that fit the pier column 18; the upper edge of the side reinforcement steel plate 122 is provided with a strip-shaped flange plate 123, and the strip-shaped flange plate 123 is laid on the surface of the capping beam 17 to realize the rapid installation operation of the side reinforcement steel plate 122, reduce the installation difficulty, and at the same time improve the bending resistance of the side reinforcement steel plate 122; connecting steel plates 125 are arranged at the upper edges of the two side reinforcement steel plates 122, and the connecting steel plates 125 are welded and fixed to the two side reinforcement steel plates 122 to realize the rapid fixation of the side reinforcement steel plates 122, and at the same time prevent the side reinforcement steel plates 122 from being lifted and deformed by the slightly expanding structural adhesive, affecting the reinforcement effect.

[0105] A new structure for bridge expansion joints includes a rapid cutting device for removing the original expansion joint structure, a new expansion joint structure, and its gantry installation and positioning support 171;

[0106] The quick cutting device includes a telescopic cross beam 161, a cutting machine 163, hydraulic legs 164, supporting pulleys 86, and guiding pulleys 85. Cutting machines 163 are provided at both ends of the telescopic cross beam 161. The telescopic cross beam 161 is supported on the supporting pulleys 86 through the hydraulic legs 164. The supporting pulleys 86 are supported on the surface of the main beam. The guiding pulleys 85 are installed on the rotating shafts 166 of the supporting pulleys 86, and the guiding pulleys 85 are supported on the side wall of the original expansion joint side beam 153.

[0107] The portal installation positioning bracket 171 is generally in an inverted U shape, with both ends supported on the main beam. It is provided with a hanging beam screw 173 and a formwork hanging screw 175. The lower part of the hanging beam screw 173 is fixed to the expansion joint side beam 183 of the new expansion joint structure. Below the formwork hanging screw 175, there are a hydraulic strut 177 and a side form 176. The side form 176 is closely attached to the ends of the main beam and the support box 185 to prevent mortar leakage from the end of the main beam when pouring high-strength mortar 187. The top surface of the expansion joint side beam 183 is flush with the surface of the main beam. High-strength mortar 187 is poured in the area enclosed by the side form 176, the main beam, the support box 185, and the expansion joint side beam 183. An expansion joint middle beam 182 is installed between the expansion joint side beams 183, and rubber strips 181 are provided at the joints between the expansion joint middle beams 182 and between the expansion joint middle beam 182 and the expansion joint side beam 183.

[0108] A support flat plate 162 is provided between the cutting machine 163 and the telescopic cross beam 161.

[0109] The portal installation positioning bracket 171 is provided with a lifting ring 172, which facilitates the overall lifting and placement of the portal installation positioning bracket 171 and the new expansion joint structure.

[0110] Both ends of the portal installation positioning bracket 171 are provided with anchor bolts 178. The anchor bolts 178 are implanted into the main beam, and the portal installation positioning bracket 171 is temporarily fixed through the anchor bolts 178 to prevent the portal installation positioning bracket 171 from shifting during the construction process.

[0111] The portal installation positioning bracket 171 is provided with a strip-shaped screw hole 174, and the hanging beam screw 173 passes through the strip-shaped screw hole 174, which facilitates fine-tuning the position of the new expansion joint structure.

Claims

1. Construction method of combined reinforcement system of existing box beams, characterized in that: It includes the following construction steps: S1. Construction of external prestressed tendon reinforcement: Construct a manhole (31) on the bottom slab (12), and fix the reinforcement steel cylinder (32) on the bottom slab (12) using a ring locking block (35); Fix the profiled steel skeleton between the bottom slab (12) and the top slab (11), adjust the height of the guiding sleeve (46) through the sliding wing plate (45), install and fix the side formwork (52) of the turning plate on both sides of the profiled steel skeleton using formwork clamps (53), and pour the profiled steel skeleton turning plate (22); Pour the anchorage block (21) at the diaphragm (13) at the end of the box girder (1), and use the opening auxiliary positioning bracket to make the prestressed tendon opening (24); The external prestressed tendon (23) passes through the guiding sleeve (46) and the prestressed tendon opening (24), and is anchored at both ends on the anchorage block (21) after tensioning; The upper end of the reinforcement steel cylinder (32) is provided with an upper support ring (33), and the lower end is provided with a lower support ring (34). The diameter of the lower support ring (34) is larger than the opening diameter on the bottom slab (12), and the diameter of the upper support ring (33) is equal to the opening diameter on the bottom slab (12); The ring locking block (35) is composed of two semi-circular steel rings, its inner diameter is equal to the outer diameter of the reinforcement steel cylinder (32), and its outer diameter is equal to the outer diameter of the lower support ring (34). Two layers of ring locking blocks (35) are arranged between the upper support ring (33) and the bottom slab (12), and the joints of the two layers of ring locking blocks (35) are staggered from each other; The lower support ring (34) is provided with a grouting hole (36), and micro-expansion cement slurry (37) is injected between the reinforcement steel cylinder (32) and the bottom slab (12) of the box girder (1). After the micro-expansion cement slurry (37) reaches the design strength, enter the interior of the box girder (1) from the manhole (31) to carry out the construction of the external prestressed tendon (23) reinforcement; Use expansion bolts (43) to fix the profiled steel skeleton between the bottom slab (12) and the top slab (11) of the box girder (1). The profiled steel skeleton includes support channel steel (41), fixed end plates (42), sliding wing plates (45) and guiding sleeves (46). The fixed end plates (42) are fixed to the bottom slab (12) and the top slab (11) respectively through expansion bolts (43). The guiding sleeve (46) is arranged on the sliding wing plate (45), and the sliding wing plate (45) is located in the sliding limit groove (44) on the support channel steel (41); After adjusting the sliding wing plate (45) to adjust the guiding sleeve (46) to the design height, spot-weld the sliding wing plate (45) to the sliding limit groove (44), and then install the anchoring steel bars (51) according to the steel bar positioning holes (47) on the support channel steel (41); And use the tension rod (54) to pass through the guiding sleeve (46) to fix the side formwork (52) of the turning plate on both sides, and then pour concrete from the pouring hole (55) to complete the pouring operation of the profiled steel skeleton turning plate (22). After the concrete reaches the design strength, remove the tension rod (54), formwork clamps (53) and the side formwork (52) of the turning plate; Rubber cushions (48) are provided on the contact surfaces of the fixed end plates (42) with the top slab (11) and the bottom slab (12); Before pouring the anchorage block (21), roughen the surface of the diaphragm (13); S2. Construction of bonding steel plates to the beam body: Bonding steel plates (25) are constructed on the surfaces of the bottom plate (12), top plate (11) and web (14) inside the box girder (1), and are fixed using internal support frames; The suspended working platform is suspended below the wing plate (15) to construct the bonding steel plates (25) outside the box girder (1) and is fixed using external support frames; The bonding steel plates (25) are bonded to the surface of the diaphragm (13) and fixed using U-shaped clamping mechanisms; S3. Construction of strengthening the cap beam by bonding steel plates: The lifting support (131) is supported between the box girder (1) and the cap beam (17), and the installation working platform (141) is lifted upwards to both sides of the cap beam (17). The cap beam (17) is wrapped between the bottom strengthening steel plate (121) and the side strengthening steel plate (122), and pressure grouting is carried out; S4. Construction of replacing the expansion joint.

2. The construction method of the in-service box girder composite reinforcement system according to claim 1, characterized in that, In the step S1, the hole-opening auxiliary positioning bracket includes a fixing clamp (91), a drill bit sealing cylinder (92), a first telescopic screw rod (96), a drill rod guiding sleeve (97), a second telescopic screw rod (910) and a support screw rod (911). The fixing clamp (91), the first telescopic screw rod (96) and the second telescopic screw rod (910) are sleeved on the support screw rod (911) through sleeves; The drill bit sealing cylinder (92) is fixed to the upper end of the first telescopic screw rod (96). One end of the drill rod guiding sleeve (97) is hinged to the drill bit sealing cylinder (92), and the other end passes through the upper end of the second telescopic screw rod (910); The connection between the drill rod guiding sleeve (97) and the drill bit sealing cylinder (92) is a conical end (98), and a conical limit nut (99) is provided on the drill rod guiding sleeve (97); A water inlet hole (93) is provided on the upper side of the drill bit sealing cylinder (92), and a water outlet hole (94) is provided on the lower side; A sealing ring (95) is provided on the contact surface between the drill bit sealing cylinder (92) and the diaphragm (13); The hole-opening auxiliary positioning bracket is clamped to the lower end of the diaphragm (13) through the fixing clamp (91) thereon. The drill bit sealing cylinder (92) is adjusted to the specified position through the first telescopic screw rod (96), and the drill rod guiding sleeve (97) is adjusted to the specified angle through the second telescopic screw rod (910). The drill rod (101) passes through the drill rod guiding sleeve (97), and the drill bit (102) is located inside the drill bit sealing cylinder (92) to drill the prestressed tendon hole (24).

3. The construction method of the in-service box girder combined reinforcement system according to claim 1, characterized in that, In the step S2, after the construction of the bonded steel plate (25) of one segment is completed, an external support frame is used to temporarily support and fix the bonded steel plate (25), and the suspension cable (83) of the first-level working platform (84) is released. Then it is slid forward along the guiding support channel steel (81). After sliding to the next working segment, it is re-suspended under the wing plate (15). Then the suspension cable (83) of the guiding support channel steel (81) is released, and it is slid forward along the first-level working platform (84) and re-suspended under the wing plate (15). Then the bonding of the external bonded steel plate (25) of the beam body, the fixation of the external support frame, and the translation of the hanging working platform are continued in a cycle according to the above steps; the internal support frame includes four symmetrically arranged telescopic rods one (61) and a support plate one (62). One end of the telescopic rod one (61) is hinged, and the other ends are respectively elastically inserted and connected with the support plate one (62). A compression spring (64) is provided at the elastic insertion joint of the telescopic rod one (61) and the support plate one (62). The telescopic rod one (61) of the internal support frame is adjusted to make the support plate one (62) closely adhere to the surface of the bonded steel plate (25). A rubber cushion one (63) is provided on the surface of the support plate one (62).

4. The construction method of the in-service box girder combined reinforcement system according to claim 1, characterized in that In the step S2, the external support frame includes a transverse support section steel (71), a lateral support section steel (72), a longitudinal connection section steel (73), a temporary anchoring cable (74), a telescopic rod two (75), and a support plate two (76). The lateral support section steel (72) is fixed at both ends of the transverse support section steel (71) to form a U-shaped structure. Both ends of the telescopic rod two (75) are respectively hinged to the lateral support section steel (72) and the support plate two (76). The support plate two (76) closely adheres to the bonded steel plate (25) on the outer side of the web (14); a support plate two (76) is also provided on the surface of the transverse support section steel (71), and the support plate two (76) closely adheres to the bonded steel plate (25) on the outer side of the bottom plate (12). Adjacent transverse support section steels (71) are connected and fixed by the longitudinal connection section steel (73). One end of the temporary anchoring cable (74) is fixed on the external support frame, and the other end passes through the wing plate opening (16) and is anchored on the wing plate (15); the hanging working platform includes a guiding support channel steel (81), a suspension cable (83), a first-level working platform (84), and a guiding pulley (85). The guiding support channel steel (81) and the first-level working platform (84) are respectively suspended at the wing plate opening (16) through the suspension cable (83). Support pulleys (86) are provided on both sides of the first-level working platform (84), and the support pulleys (86) are supported inside the guiding support channel steel (81). A second-level working platform (88) is further provided under the first-level working platform (84), and the second-level working platform (88) is suspended under the first-level working platform (84) through the suspension cable (83). An end connection section steel (82) is provided at the end of the guiding support channel steel (81), and support pulleys (86) and pulley struts (87) are provided on the side of the working platform; a rubber cushion two (77) is provided on the surface of the support plate two (76).

5. The construction method of the in-service box girder combined reinforcement system according to claim 1, characterized in that, In the step S2, the U-shaped clamping mechanism includes a screw rod (111), a telescopic strut (114), a telescopic tie rod (115), and a clamping plate (116). The telescopic strut (114) and the telescopic tie rod (115) are installed on the screw rod (111) through a sliding sleeve (112), and the sliding sleeve (112) is constrained by a limit nut (113) on the screw rod (111). A foldable telescopic support leg (117) is provided below the U-shaped clamping mechanism, and the telescopic support leg (117) supports on the bottom plate (12). Adjust the lengths of the telescopic strut (114) and the telescopic tie rod (115) to unfold the U-shaped clamping mechanism, so that the telescopic strut (114), the telescopic tie rod (115), and the screw rod (111) form a triangle, and then the sliding sleeves (112) at the lower ends of the telescopic strut (114) and the telescopic tie rod (115) are constrained by the limit nut (113) to clamp the bonding steel plates (25) on both sides of the diaphragm plate (13).

6. The construction method of the in-service box girder combined reinforcement system according to claim 1, characterized in that, In the step S3, a bottom support foot (132) and a top fastening screw rod (133) are provided on the lifting bracket (131). The bottom support foot (132) supports on the capping beam (17), and the top fastening screw rod (133) supports on the lower surface of the box girder (1). A winch (134) and a steel wire rope (135) are also provided on the lifting bracket (131). A horizontal lateral ejector rod (142) is provided on the installation operation platform (141). The installation operation platforms (141) on both sides of the capping beam (17) are symmetrically arranged, and a connecting steel wire rope (143) is arranged at the bottom of the installation operation platform (141) to connect and fix the installation operation platforms (141) on both sides. Arc-shaped notches that fit the pier column (18) are provided at both ends of the bottom reinforcement steel plate (121). A strip-shaped flange plate (123) is provided on the upper edge of the side reinforcement steel plate (122), and the strip-shaped flange plate (123) is placed on the surface of the capping beam (17). Connecting steel plates (125) are provided on the upper edges of the two side reinforcement steel plates (122), and the connecting steel plates (125) are welded and fixed to the two side reinforcement steel plates (122). Rubber sealing strips (127) are provided at the ends of the bottom reinforcement steel plate (121) and the edges of the side reinforcement steel plates (122). Support the lifting bracket (131) between the box girder (1) and the capping beam (17), and then construct the weld (124) between the bottom reinforcement steel plate (121) and the side reinforcement steel plate (122) to wrap the capping beam (12) between the bottom reinforcement steel plate (121) and the side reinforcement steel plate (122). Through the pressure grouting holes (126) on the bottom reinforcement steel plate (121) and the side reinforcement steel plate (122), inject a slightly expanding structural adhesive into the gap between the bottom reinforcement steel plate (121), the side reinforcement steel plate (122), and the capping beam (17).

7. The construction method of the in-service box girder combined reinforcement system according to claim 1, characterized in that, In the step S4, first, the original rubber strip (151) and the original expansion joint middle beam (152) are removed. Then, the quick cutting device is erected at the expansion joint, the length of the telescopic cross beam (161) is adjusted so that the cutting blade of the cutting machine is located outside the original support box body (155), the position of the limit pulley (167) is adjusted to make it closely attached to the side wall of the original expansion joint side beam (153). Finally, the height of the cutting blade of the cutting machine is adjusted through the hydraulic support leg (164) to perform cutting operations on the end of the box girder (1) until the specified depth is cut. Then, the quick cutting device is removed, the concrete at the end of the box girder (1) is chiseled along the cutting seam, and the original expansion joint side beam (153), the original support longitudinal beam (154) and the original support box body (155) are integrally removed. The quick cutting device includes a telescopic cross beam (161), a cutting machine (163), a hydraulic support leg (164), a moving pulley (165) and a limit pulley (167). Cutting machines (163) are provided at both ends of the telescopic cross beam (161). A support flat plate (162) is provided between the cutting machine (163) and the telescopic cross beam (161). The telescopic cross beam (161) is supported on the moving pulley (165) through the hydraulic support leg (164). The moving pulley (165) is supported on the surface of the box girder (1). The limit pulley (167) is installed on the rotating shaft (166) of the moving pulley (165), and the limit pulley (167) is supported on the side wall of the original expansion joint side beam (153).

8. The construction method of the in-service box girder combined reinforcement system according to claim 7, characterized in that In the step S4, after cutting the original expansion joint structure, stud bolts (186) are installed on the end of the box girder (1) and the support box body (185) of the new expansion joint structure. The lifting beam screw rod (173) is spot-welded and fixed to the expansion joint side beam (183). Then, through the lifting ring (172), the gantry installation positioning bracket (171) together with the expansion joint side beam (183), the support longitudinal beam (184), and the support box body (185) are integrally hoisted and placed in position. The hydraulic strut (177) is adjusted to make the side formwork (176) closely adhere to the end of the box girder (1). Then, the lifting beam screw rod (173) is adjusted to make the end of the support box body (185) closely adhere to the side formwork (176), and the top surface of the expansion joint side beam (183) is flush with the surface of the box girder (1). Next, the anchor bolts (178) are driven into the box girder (1) to fix the gantry installation positioning bracket (171). Then, high-strength cement mortar (187) is poured between the box girder (1) and the support box body (185). After the high-strength cement mortar (187) reaches the design strength, the gantry installation positioning bracket (171) is removed, and the expansion joint middle beam (182) and the rubber strip (181) are installed. The gantry installation positioning bracket (171) is integrally in an inverted U shape, with both ends supported on the box girder (1). It is provided with a lifting beam screw rod (173) and a formwork lifting screw rod (175). The lower part of the lifting beam screw rod (173) is fixed to the expansion joint side beam (183) of the new expansion joint structure. The lower part of the formwork lifting screw rod (175) is provided with a hydraulic strut (177) and a side formwork (176). The side formwork (176) closely adheres to the ends of the box girder (1) and the support box body (185). The gantry installation positioning bracket (171) is provided with a lifting ring (172). Both ends of the gantry installation positioning bracket (171) are provided with anchor bolts (178), and the anchor bolts (178) are implanted into the box girder (1). The gantry installation positioning bracket (171) is provided with a strip-shaped screw hole (174), and the lifting beam screw rod (173) passes through the strip-shaped screw hole (174).

9. The existing box girder composite reinforcement system is characterized in that, Obtained by the method according to any one of claims 1 to 8.

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