CN221072336U - Bridge external prestress reinforcing structure - Google Patents

Abstract

The application provides an external prestress reinforcing structure of a bridge, and belongs to the technical field of methods for maintaining or reinforcing existing bridges. The bridge main body is used as a treatment object, the bridge main body comprises a middle cross beam and a bottom plate, an anchoring block is arranged at the middle cross beam, a steering block is fixed at the bending moment change position of the bottom plate, an external prestress steel beam is arranged on the anchoring block, is distributed above the bottom plate along the span direction and passes through the steering block, and the tail end of the external prestress steel beam is fixed at the bridge beam end. The scheme is used for reinforcing the bridge, the usability and durability of the bridge body structure of the bridge can be improved, and the advantages of the down-warping disease and the bending bearing capacity of the bridge body and the like are properly improved.

Description

Bridge external prestress reinforcing structure

Technical Field

The application relates to an external prestress reinforcing structure of a bridge, and belongs to the technical field of methods for maintaining or reinforcing existing bridges.

Background

As shown in fig. 1, a large-span bridge generally comprises bridge approaches 6 at both ends and a plurality of midspan 7 positioned between the bridge approaches 6, and bridge bodies of the bridge approaches 6 and the midspan 7 are supported by piers, caps, pile foundations, and the like between the ground. The number of midspan 7 allocated varies with the environment of use. The large-span bridge meets the communication requirements of complex geology such as most mountain canyons, large rivers and the like. However, with the increase of service life, the bridge gradually has the problem of fatigue cracking under the long-term superposition of adverse factors such as earthquake, heavy load, initial manufacturing defects and the like. The fatigue cracking problems are mainly manifested by severe downwarping of the main bridge, cracking of the middle span 7 bottom plate, and non-directional cracking of the top plate, the auxiliary plate, the pier top and other areas, and the work of cracking the bridge structural member weakens the use efficiency.

To solve the fatigue cracking problem, a series of reinforcement studies have been made in the industry. Such as:

CN112813852A aims at the slippage, dislocation and sinking of a beam body of an in-service bridge caused by the inclination of a pier column, and performs correction and resetting between upper and lower structures of grain robbing, so as to repair and strengthen the pier column. CN113309015A aims at the problem that the common method for reinforcing the fatigue fracture of the butt welding seam of the longitudinal ribs is easy to passively introduce more fatigue vulnerable parts, and the reinforcing members made of memory materials are introduced at the two sides of the welding seam, and the prestress is provided by the materials, so that the crack is closed. CN202055185U is directed against the difficult problem of construction that fiber reinforced composite material mode such as carbon fiber consolidates existence of large-span bridge, installs steel strand wires, pulley, little steelframe etc. additional between the pier, lifts the bridge with the help of little steelframe and steel strand wires, reaches the transportation car and passes, the purpose of reinforcing water flow resistance ability. The anti-fatigue reinforcement repair of the in-service bridge is further carried out by means of a shear connector and a reinforcing mesh (such as CN 109338907A), a tensioning support and a jack are matched (such as CN 105862608A), a corrugated steel web member (such as CN 104695339A) is additionally arranged in a box girder box chamber, and the like.

The reinforcing mode plays an urgent reinforcing role on serious and obvious large cracks, but has very limited repairing role on main body cracks of bridges such as cross beams, top plates and the like with uncertain crack directions, and the existence of the cracks is exactly the key point for measuring the bearing capacity of the bridges. The existence of the cracks and the fissures is also a precursor of the later bridge when serious bearing problems occur, and how to realize the pre-reinforcement of the bridge and avoid the emergency repair when the problems occur is a difficult problem to be solved in the field.

Disclosure of utility model

In view of the above, the application provides an external prestress reinforcement structure for a bridge, which not only realizes the repair of various cracks of the bridge, but also improves the usability and durability of the bridge body structure, and properly improves the downwarping defect and bending bearing capacity of the bridge body.

Specifically, the application is realized by the following scheme:

The utility model provides an external prestressing force reinforced structure of bridge to the bridge main part is processing object, and the bridge main part includes middle crossbeam and bottom plate, middle crossbeam department is provided with the anchor piece, turns to the piece and is fixed in bottom plate moment of flexure change department, is provided with external prestressing force steel bundle on the anchor piece, external prestressing force steel bundle distributes in the bottom plate top along span direction to after passing the turning to the piece, the end of external prestressing force steel bundle is fixed in bridge girder end.

The reinforcing structure comprises an anchoring block, an external prestress steel beam and a turning block to form an external prestress reinforcing member of a large-span bridge, wherein the anchoring block is a middle acting point of a bridge main body, one end of the external prestress steel beam passes through the bridge main body along the span direction (length direction) after being pulled out from the anchoring block, and turns through the turning block when passing through a bending moment change position, finally, the tail end of the external prestress steel beam reaching a design tensile force is fixed at the beam end of a reinforced concrete beam, the bridge main body is pulled along the span direction by the design tensile force, and the existing cracks of the bridge main body are stably and continuously closed by the pulling action; in the bridge passing process, external force is directly transferred to the middle cross beam, the bottom plate, the top plate and other parts of the bridge main body from the bridge surface, the acting force is transferred to the external prestress steel beam through the anchoring block, and the destructive effect is reduced along the span direction under the action of the designed tension force, so that the secondary expansion of cracks is effectively avoided. Through the bridging effect and the re-expansion avoiding effect of the existing cracks, the external prestress reinforcement of the large-span bridge is realized, and the bridge meets the requirements of usability and durability.

Further, as preferable:

The anchor block comprises an anchor head, a bearing plate, a spiral rib and a corrugated pipe, wherein one side of the bearing plate is connected with the corrugated pipe, the periphery of the connecting end of the bearing plate is provided with the spiral rib fixed with the middle cross beam, the anchor head is installed on the other side of the bearing plate, a limiting plate is installed on the outer side of the anchor head, one end of an outer prestress steel beam is located in the corrugated pipe, and the other end of the outer prestress steel beam penetrates through the bearing plate and the anchor head to be connected with the limiting plate through a wedge.

The external prestress steel strand comprises steel strands and clamping pieces, wherein a plurality of groups of steel strands are positioned by the clamping pieces, and the steel strands are connected with the wedge. More preferably, a spring is sleeved between the clamping piece and the wedge. The steel strand consists of a plurality of steel wires and a lantern ring sleeved on the periphery of the steel wires.

A template is arranged between the bearing plate and the corrugated plate, and slurry is filled in the template and the bearing plate.

The connection mode of the anchoring block and the external prestress steel beam is as follows: the method comprises the steps of steel strand penetration, anchor installation, jack installation, tensioning equipment, tensioning, anchoring, jack removal and tensioning equipment, grouting and beam storage.

The external prestress steel beam sleeve is sleeved with a shock absorber. More preferably, the shock absorber comprises an upright post, a rubber sleeve and a jacket, wherein the jacket is arranged on a bottom plate of the bridge main body through the upright post, the rubber sleeve is in a semicircular shape and is positioned in the jacket, and an external prestress steel beam penetrates through a through hole formed by the two rubber sleeves. The semicircular rubber sleeve is in direct contact with the external prestress steel beam, the elastic structure of the rubber sleeve buffers the vibration action of the bridge in operation, and the non-closed structure provides a larger buffer space for deformation of the rubber sleeve and has a good damping effect. The stand is telescopic structure, can adjust the installation height of external prestressing force steel bundle according to the installation environment of difference, better elimination vehicle resonance influence.

The steering block is of an annular structure fixed on the bottom plate and comprises a straight line section, an arc section and a straight line section which are sequentially arranged, and the external prestress steel beam and the steering block are eccentrically arranged. The external prestress steel beam eccentrically penetrates through the annular structure, torque can be well transmitted, the structure of the external prestress steel beam is endowed with good bearing capacity and high anti-seismic performance, vibration of the bridge can be reduced by the external prestress steel beam, influence of vehicle load on the bridge is reduced, the load is transmitted to a bridge pier or a foundation, and stability and safety of driving are improved. The steering block is used as a load transfer unit, the height of the steering block gradually increases from the arc section to the straight line section, the stress impact of the steering block is buffered, the three-section structure not only strengthens the outer wall strength of the straight line section, but also leads the traction path of the external prestress steel beam to be guided, and the structural stability of the whole steering block is improved.

The external prestress steel bundles are matched with the steering block, the shock absorber and the anchoring block to provide certain prestress for the deformation of the inside (hollow) of the bridge to prevent deformation and cracking, the external prestress steel bundles are also convenient to pull at different positions of the hollow structure in the bridge, the various fatigue cracking with unstable directions and unequal cracks is met, the reinforcing process is developed according to the mechanical performance of the bridge in the normal use process, by means of external prestress, the existing bridge is provided with certain reserved deformation quantity, passive reinforcement is converted into active reinforcement, and the cooperation of the structures also plays roles in recovering the use function of the original structure and improving the reliability and durability of the structure.

Drawings

FIG. 1 is a schematic structural view of a conventional large span bridge;

FIG. 2 is a schematic side view of the present application;

FIG. 3 is a schematic top view of the present application;

FIG. 4 is a cross-sectional view of an in vitro pre-stressed steel beam in accordance with the present application;

FIG. 5 is a schematic view of the connection structure of the anchor block and the external prestress steel beam according to the present application;

FIG. 6 is a schematic view of a steering gear according to the present application;

FIG. 7 is a cross-sectional view in the M-M direction of FIG. 6;

FIG. 8 is an enlarged view of part A of FIG. 6;

FIG. 9 is a schematic diagram of the front structure of a shock absorber according to the present application;

fig. 10 is a schematic side view of a shock absorber according to the present application.

Reference numerals in the drawings: 1. a bridge body; 11. a middle cross beam; 12. a bottom plate; 13. a top plate; 2. a damper; 21. a rubber sleeve; 22. a jacket; 23. a column; 231. a support rod; 232. a loop bar; 24. a first nut; 25. a gasket; 26. a second nut; 3. an external prestress steel beam; 31. steel strand; 311. a collar; 312. a steel wire; 32. a clamping piece; 33. a steel backing plate; 34. a spring; 35. a wedge; 4. a steering block; 41. a straight line segment; 42. a circular arc section; 5. an anchor block; 51. a limiting plate; 52. an anchor head; 521. a fastener; 53. a bearing plate; 54. a template; 55. spiral ribs; 56. a slurry; 57. a bellows; 5a, anchoring block I; 5b, anchoring a second block; 6. bridging; 7. midspan.

Detailed Description

In this embodiment, the bridge body 1 is a hollow bridge structure, and the bridge body shown in fig. 2 and 3 is used as a processing object, and the bridge body 1 includes a middle cross beam 11, a bottom plate 12 and a top plate 13. The reinforcement is mainly concentrated at two parts of the middle cross beam 11 and the bottom plate 12: the middle beam 11 is provided with an anchoring block 5 (generally, two sides of the middle beam 11 are respectively provided with an anchoring block, the first anchoring block 5a is the fixed position/pulling-out end of the initial end of the next external prestress steel beam, the second anchoring block 5b is the fixed position of the tail end of the previous external prestress steel beam), the bending moment change position of the bridge main body 1 is provided with a steering block 4, the external prestress steel beam 3 is pulled out from the anchoring block 5 along the span direction (length direction), the external prestress steel beam 3 passes through the steering block 4, the tail end is fixed at the beam end of the bridge main body 1, and the external prestress steel beam 3 is stretched to the designed tensile force.

The specific operation steps are as follows:

(1) Measuring the positions of original box girder steel bars and steel bundles of the contact surface of the bridge main body 1: according to the position of the newly-added anchoring cross beam, namely the anchoring block 5, marked in the reinforcing construction design drawing, the positions of the web plate at the anchoring block 5 and the original common steel bars of the top plate and the bottom plate are measured by a steel bar detector, and marked by red paint.

(2) Surface treatment of the original box Liang Dai bar planting position: the parts of the anchoring block 5 and the steering block 4 are required to be ground, scraps are removed, the surface of fresh concrete is exposed, and the fresh concrete is washed clean by high-pressure water.

(3) According to the design drawing, shear grooves are cut in the ranges of the anchoring block 5 and the steering block 4, the groove depth is 2cm, and the distance is 20cm.

(4) Drilling and in-hole treatment: drilling holes in the positions of the anchoring block 5 and the steering block 4, wherein the drilling depth is not less than the design depth, and cleaning floating dust in the holes by using compressed air. The cleaning of floating dust in the hole must be from the bottom of the hole to the hole opening.

(5) Reinforcing steel bars implanted with the anchoring blocks 5 and the turning blocks 4: and (3) starting from the bottom of the bar planting hole, removing paint and rust spots on the steel bars in the bar planting glue injection hole, slowly inserting the steel bars of the anchoring block 5 and the steering block 4 into the bar planting hole in a co-rotating manner, and enabling the length of the steel bars in the bar planting hole to be not smaller than the design length.

The process flow of the bar planting comprises the following steps: positioning, drilling, cleaning holes, rust removal of reinforcing steel bars, glue preparation, glue injection, bar planting, solidification, protection and inspection.

Table 1: the diameter of the planted bar and the corresponding diameter of the drilled hole

After the hole arrangement positioning is carried out on the reinforcement planting holes according to the design requirement, a reinforcement detector is arranged in a construction unit, the reinforcement detector is used for determining whether the stressed reinforcement exists at the hole position, and the position is changed properly when the reinforcement exists. The original steel bars are prevented from being damaged as much as possible, and the damage of the planted steel bars to the steel bars in the original structure is controlled to be lower than 15%. Before the bar is planted, whether a crack exists or not is checked, and the bar is not planted at the crack.

The positions and the diameters of the bar planting holes are required to meet the following basic requirements besides meeting the design requirements: the clearance is larger than the thickness of the reinforcement protection layer, and the inner side of the original structure stirrup must be implanted; the depth of the structure of the implanted steel bar is more than or equal to +40mm.

The reinforcing steel bars adopted by the reinforcing steel bar are HRB 400-grade ribbed reinforcing steel bars without special requirements, the national standard requirements of GB 1499.2-2018 are met, mechanical cutting is required, and oxygen cutting is not allowed to be adopted on the end face.

The embedded depth of the steel bar is used for deducting the peeling layer and the crack layer on the surface of the concrete.

According to the use instruction and the type requirement configuration of a bar planting adhesive manufacturer, the adhesive injection is completed at one time: firstly, the bar planting glue is directly put into a glue gun, a stirring head is screwed to the head of the glue, the glue gun is buckled until the glue flows out, the glue which is beaten out for the first time is not used, and the glue can be used when the glue flows out to form uniform gray. When injecting glue, the stirring head is inserted into the bottom of the hole to start injecting glue, and about 2/3 of the glue is injected into the hole. After each time the glue gun is buckled, the stop is carried out for 5-6 seconds, and then the next glue gun is buckled. When the next hole is injected, the tongue behind the glue gun is pressed down, and the glue gun is automatically pressurized, so that the glue is prevented from continuously flowing out, and waste is avoided. When new glue is replaced, the tongue at the back of the glue gun is pressed down, the pull rod is pulled out, and the glue gun is taken out.

(6) Binding reinforcing steel bars of the anchoring block 5 and the steering block 4: after the cement is solidified (generally 20-60 minutes), the steel strands 31, the clamping pieces 32, the steel gaskets 33, the limiting plates 51, the anchor heads 52, the bearing plates 53, the corrugated pipes 57 and the like of the newly added external prestress steel bundles 3 are arranged, and the rest of the steel bars of the anchor blocks 5 and the steering blocks 4 are bound to form a steel bar framework.

(7) Pouring concrete: after the framework is formed, the mould is erected according to the shapes of the anchoring block 5 and the steering block 4, the positions of the steel stranded wires 31 and the anchor heads 52 are noted, interface glue is sprayed between the contact surfaces of new and old concrete, and then concrete is poured.

(8) And (3) curing concrete: after the casting is finished, the maintenance is reinforced, and when the age is not less than 7 days and the design strength reaches more than 90%, the prestress can be stretched.

(9) Tensioning prestress: the left web plate and the right web plate of the box girder are simultaneously tensioned corresponding to the external prestress steel bundles 3, the tensioning force is tensioned in batches, the tensioning force is tensioned to 60% of the designed tensioning force, and then the tensioning force is tensioned to the designed tensioning force.

The reinforcement structure formed by the above process is shown in fig. 2 and 3: the anchoring block 5 is positioned at the upper part of the middle cross beam 11, the steering block 4 is fixed on the bottom plate 12, one end of the plurality of external prestress steel bundles 3 and the anchoring block 5 are constructed in a box girder prestress tensioning mode, the other end of the external prestress steel bundles passes through the hollow cavity of the bridge main body 1, steering is finished at the bridge bending moment change position by the hard steering block 4, steel wires at different positions are convenient to steer, the tail end of the external prestress steel bundles 3 reaching the design tension force is finally fixed at the beam end of the reinforced concrete beam, the bridge main body 1 is pulled along the span direction by the design tension force, and the existing cracks of the bridge main body are stably and continuously bridged by the pulling action; in the bridge passing process, external force is directly transferred to the middle cross beam 11, the bottom plate 12, the top plate 13 and other parts of the bridge main body from the bridge surface, the acting force is transferred to the external prestress steel beam 3 through the anchoring block 5, and the destructive effect is reduced along the span direction under the action of the designed tension force, so that the secondary expansion of cracks is effectively avoided. Through the bridging effect and the re-expansion avoiding effect of the existing cracks, the external prestress reinforcement of the large-span bridge is realized, and the bridge meets the requirements of usability and durability.

The connection relation between the external prestress steel beam 3 and the anchoring block 5 is shown in fig. 4 and 5. The external prestress steel strand 3 is connected with the middle beam 11 by adopting a mode of penetrating the steel strands 31 (comprising loading of the clamping pieces 32, the steel backing plates 33, the wedges 35 and the like), installing the anchors (comprising the anchor heads 52, the limiting plates 51, the bearing plates 53, the spiral ribs 55, the corrugated pipes 57 and the like), installing the jacks and the tensioning equipment, tensioning, anchoring, removing the jacks and the tensioning equipment, grouting and storing the beams.

The diameter D of the clip 32 is controlled during installation. The formed anchoring block 5 comprises an anchor head 52, a bearing plate 53, a spiral rib 55 and a corrugated pipe 57, wherein one side of the bearing plate 53 is connected with the corrugated pipe 57, the outer periphery of the connecting end of the bearing plate 53 is provided with the spiral rib 55 fixed with the middle cross beam 11, the other side of the bearing plate 53 is provided with the anchor head 52, the outer side of the anchor head 52 is provided with a limiting plate 51, one end of an outer prestress steel beam 3 is positioned in the corrugated pipe 57, and the other end of the outer prestress steel beam passes through the bearing plate 53 and the anchor head 52 to be connected with the limiting plate 51 through a wedge 35.

Referring to fig. 4, the external prestress steel strand 3 comprises steel strands 31, clamping pieces 32 and a steel backing plate 33, wherein a plurality of groups of steel strands 31 are positioned by the clamping pieces 32, the clamping pieces 32 are fixed on the steel backing plate 33, and the steel strands 31 are connected with wedges 35. The steel backing plate 33 is connected with the anchor head 52 through a fastener 521, and a spring 34 is sleeved on the steel stranded wire 31 between the clamping piece 32 and the wedge 35 between the steel backing plate 33 and the anchor head 52. Each group of steel strands 31 is composed of a plurality of steel wires 311 and a lantern ring 312 sleeved on the periphery of the steel wires 311, and the multi-layer structure of the external prestress steel bundle 3 gives possibility of reserving prestress.

A template 54 is also arranged between the bearing plate 53 and the corrugated plate 57, and after grouting, the template 54 and the bearing plate 53 are filled with sizing agent 56.

The steering block 4 is of an annular structure as shown in fig. 6, and comprises a straight line section 41, an arc section 42 and a straight line section which are sequentially arranged, and the external prestress steel beam 3 and the steering block 4 are eccentrically arranged as shown in fig. 7. The external prestress steel beam eccentrically penetrates through the annular structure, torque can be well transmitted, the structure of the external prestress steel beam is endowed with good bearing capacity and high anti-seismic performance, vibration of the bridge can be reduced by the external prestress steel beam 3, influence of vehicle load on the bridge is reduced, the load is transmitted to a bridge pier or a foundation, and stability and safety of driving are improved.

Referring to fig. 8, a bell mouth section is formed at the port of the straight line section 41, the height of the bell mouth section gradually increases from the circular arc section 42 to the straight line section 41, the inclination angle θ is 10 °, the self length D2 thereof is 20mm, and the distance D1 from the port is 50mm. The steering block 4 is used as a load transfer unit, the height of the steering block gradually increases from the circular arc section 42 to the straight line section 41, the stressed impact of the steering block is buffered, the three-section structure not only strengthens the outer wall strength of the straight line section, but also guides the traction path of the external prestress steel beam, and the structural stability of the whole steering block is improved.

The shock absorber 2 can be arranged on the external prestress steel beam 3 according to different in-service conditions of the bridge. In connection with fig. 9 and 10: the shock absorber 2 comprises a stand column 23, a rubber sleeve 21 and a jacket 22, wherein the jacket 22 is of a hollow cylinder structure and is arranged on the bottom plate 12 of the bridge main body through the stand column 23; the rubber sleeve 21 is of a two-piece structure, the rubber sleeve 21 is positioned in the jacket 22, two pieces of the rubber sleeve 21 are wrapped on the periphery of the external prestress steel beam 3, the jacket 22 is sleeved on the periphery of the rubber sleeve 21 and fastened by a second nut 26 and the like, the jacket 22 is fixed with the upright post 23 through a gasket 25, a first nut 24 and the like, and the upright post 23 is fixed on the bottom plate 12 through a fastener (the same can be adopted as the nut). The semicircular rubber sleeve 21 is in direct contact with the external prestress steel beam 3, the elastic structure of the rubber sleeve 21 buffers the vibration action in the bridge operation, and the non-closed structure provides a larger buffer space for deformation of the rubber sleeve, so that the damping effect is good.

The upright 23 in the above structure can adopt a telescopic structure, for example, a supporting rod 231 and at least one sleeve rod 232 are adopted, the supporting rod 231 is fixed with the bottom plate 12, and the sleeve rod 232 can stretch and retract relative to the supporting rod 231 so as to change the overall height of the upright 23; according to different installation environments, the installation height of the external prestress steel beam is adjusted, and the resonance influence of the vehicle is eliminated better.

For the crack that appears in roof 13 inboard, can also adopt the mode of pasting the billet to consolidate, consolidate the step and be: pouring a crack with high polymer resin, cleaning and leveling the surface of a sticking part, implanting a bolt for fixing a steel plate, polishing the surface layer of the steel plate on the bonding surface, providing a grouting hole, installing and fixing a reinforced steel plate, ensuring the gap between the steel plate and the concrete surface to be 2-3 mm, ensuring the thickness of a pouring adhesive layer to be 2-3 m, sealing edges around the steel plate, pressing a bonding adhesive through the grouting hole without gaps, solidifying, performing corrosion-resistant treatment on the steel plate, filling the gap of the steel plate on the outer surface with a repairing adhesive, and coating.

The specific construction process comprises the following steps:

Firstly, concrete surface treatment: according to the requirements of a design drawing and in combination with on-site measurement positioning, discharging a large sample of the position of a steel plate on the surface of the concrete to be reinforced by bonding steel, chiseling surface mortar with the thickness of 6-8 mm on the surface of the concrete in the area to be bonded by bonding steel, exposing solid concrete stones, forming a flat rough surface, lightly chiseling and leveling uneven surface parts by using a sharp chisel, removing surface floating pulp by using a steel wire wheel, removing surface loose matters, finally blowing oil-free compressed air to remove surface dust or cleaning with clear water, and wiping the surface by using absorbent cotton to be dipped with acetone after the surface is completely dried. For the concrete at the position of the box Liang Niantie, the concrete may be uneven, and measures should be taken to treat the concrete during construction so that the concrete meets the flatness required by adhering the steel plates.

Secondly, drilling and embedding bolts: and (3) according to the requirements of a design drawing, paying out the position to be drilled, detecting the position of the steel bar of the original bridge by using a reinforced concrete protection layer tester, adjusting and finally determining the drilling position, and then drilling. The original steel bar should be avoided being bumped during drilling. The distance between the embedded full-thread screw and the edge of the adhered steel plate is controlled to be about 5 cm. The aperture and the depth of the hole should be strictly constructed according to the design requirement, and the planted bolt hole should be cleaned. The adhesive for filling the bolt adopts a product which meets the requirements, and the construction process must meet the technical requirements of bolt implantation. After the adhesive is cured, the tensile resistance meets the following requirements, and the design value of the tensile resistance of M12 is 24kN.

Thirdly, punching and surface treatment are carried out on the steel plate to be bonded: and (3) blanking the adhered steel plate according to the actual lofting of the on-site concrete, punching the steel plate to be adhered according to the on-site embedded screw rod in a matched mode, and then derusting and roughening the adhered surface of the steel plate by using a polishing grinder or a steel wire brushing and grinding machine, wherein the larger the polishing roughness is, the better the polishing roughness is, and the polishing lines are perpendicular to the stress direction of the steel plate. And finally wiping the surface of the steel plate by using absorbent cotton to be dipped with acetone, attaching the steel plate to a preset position, and attaching and fixing the steel plate by using an embedded screw rod.

Fourth, steel plate installation and welding: and (3) blanking the steel plate according to actual lofting on the site concrete, and carrying out matched punching on the steel plate to be poured according to the screw embedded on the site. Placing a 3mm spacer between the concrete and the steel plate, sleeving the steel plate on a bolt, adjusting the level and fixing the steel plate, and ensuring that the gap between the steel plate and the surface of the concrete is near 2mm so as to ensure that the thickness of a pouring adhesive layer is near 2 mm; and welding the joints of the steel plates to finish the installation of the steel plates. Measures for avoiding burning the concrete with the original structure should be taken when the steel plates are welded.

Fifth step, edge sealing adhesive: the steel-bonding pouring adhesive is required to be subjected to edge sealing, and the steel plate edge sealing adhesive is prepared and used after being completely solidified and has enough strength.

Sixthly, glue injection construction (edge sealing of steel plate and pouring of structural glue): sealing edges, namely bonding an injection glue nozzle on an injection hole of a steel plate, inserting an exhaust pipe into the edge of the steel plate, covering a cover bowl on an expansion bolt head, and sealing the edge of the steel plate by using steel plate sealing glue to finish sealing edges. The glue injection nozzle and the air outlet holes are arranged at intervals of 1 m. After the edge sealing adhesive is completely solidified (about 12 hours) and has a certain strength, ventilation and pressure test are performed to check that the edge sealing of the steel plate is good, and then the subsequent construction of pouring the structural adhesive can be performed. The pressure pump is used for pouring the adhesive steel pouring glue in the pressure tank into the gap between the steel plate and the concrete through the plastic guide pipe from the pouring nozzle at the pressure of 0.2MPa, the pressure is kept stable, the pressurizing is stopped when the vent hole emits the slurry, the vent hole is blocked by the steel plate edge sealing glue, and the lower pressure is maintained for about 10 minutes, or the pouring work is continued until the glue solution flows out from all the vent holes. During the pouring process, the steel plate was tapped with a rubber hammer to confirm whether the pouring was dense.

Seventh, maintenance: after the glue injection construction is finished, standing and curing should be carried out for 72 hours. During this time, the reinforced part must not be affected by the impact and vibration.

Eighth step, the surface of the steel plate is subjected to corrosion prevention treatment.

In the scheme, the external prestress steel beam 3 is matched with the steering block 4, the shock absorber 2 and the anchoring block 5, a certain prestress storage is provided for deformation and cracking of the bridge, the external prestress steel beam 3 is pulled at different positions of the hollow structure in the bridge, the requirements of various fatigue and cracking reinforcement with uncertain directions and unequal cracks are met, the reinforcement process is unfolded according to the mechanical performance of the bridge in use, the existing bridge is given a certain storage deformation amount, passive reinforcement is converted into active reinforcement, and the cooperation of the structures also plays roles of recovering the use function of the original structure and improving the reliability and durability of the structure.

Claims (9)

1. Bridge external prestress reinforcement structure to the bridge main part is processing object, and the bridge main part includes well crossbeam and bottom plate, its characterized in that: the middle beam is provided with an anchoring block, the steering block is fixed at the bending moment change position of the bottom plate, the anchoring block is provided with external prestress steel bundles, the external prestress steel bundles are distributed above the bottom plate along the span direction and pass through the steering block, and the tail ends of the external prestress steel bundles are fixed at the bridge beam ends.

2. The bridge extracorporeal pre-stressed reinforcement structure of claim 1, wherein: the anchor block comprises an anchor head, a bearing plate, a spiral rib and a corrugated pipe, wherein one side of the bearing plate is connected with the corrugated pipe, the periphery of the connecting end of the bearing plate is provided with the spiral rib fixed with the middle cross beam, the anchor head is installed on the other side of the bearing plate, a limiting plate is installed on the outer side of the anchor head, one end of an outer prestress steel beam is located in the corrugated pipe, and the other end of the outer prestress steel beam penetrates through the bearing plate and the anchor head to be connected with the limiting plate through a wedge.

3. The bridge extracorporeal pre-stressed reinforcement structure of claim 2, wherein: the external prestress steel strand comprises steel strands and clamping pieces, wherein a plurality of groups of steel strands are positioned by the clamping pieces, and the steel strands are connected with the wedge.

4. A bridge extracorporeal pre-stressed reinforcement structure according to claim 3, wherein: a spring is sleeved between the clamping piece and the wedge.

5. A bridge extracorporeal pre-stressed reinforcement structure according to claim 3, wherein: the steel strand consists of a plurality of steel wires and a lantern ring sleeved on the periphery of the steel wires.

6. The bridge extracorporeal pre-stressed reinforcement structure of claim 2, wherein: a template is arranged between the bearing plate and the corrugated plate, and slurry is filled in the template and the bearing plate.

7. The bridge extracorporeal pre-stressed reinforcement structure of claim 1, wherein: and the external prestress steel beam is sleeved with a shock absorber.

8. The bridge extracorporeal pre-stressed reinforcement structure of claim 7, wherein: the shock absorber comprises a rubber sleeve and a jacket, the jacket is arranged on the bottom plate, the rubber sleeve is of a two-piece structure and is positioned in the jacket, and an external prestress steel beam penetrates through a through hole formed by the two rubber sleeves.

9. The bridge extracorporeal pre-stressed reinforcement structure of claim 1, wherein: the steering block is of an annular structure and comprises a straight line section, an arc section and a straight line section which are sequentially arranged, and the external prestress steel beam is eccentrically arranged relative to the steering block.