阅读说明：本技术 一种斜拉桥正交异性板钢箱梁整体维修加固施工方法 (Cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method ) 是由 王希岗 郭之起 徐淑亮 李伟 张奉春 张永江 李超 章晋旺 张常轩 吴战平 张立 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种斜拉桥正交异性板钢箱梁整体维修加固施工方法,整体施工顺序包括：先进行喷砂除锈,喷完一定节段后清理磨料及锈渣,再对裂缝、焊缝开焊、严重锈蚀位置进行标记,下一步进行油漆喷涂,防止钢箱内表面再度锈蚀,待油漆实干后对缺陷位置进行修补。本发明结合现有钢箱梁的常规结构,根据钢箱梁不同的缺陷提出不同的维修改造施工工艺,为钢箱梁的加固提出一套完整的施工方法,为类似工程提供借鉴,具有极高的推广价值。(The invention discloses a construction method for integrally maintaining and reinforcing an orthotropic plate steel box girder of a cable-stayed bridge, which comprises the following steps: carrying out sand blasting and rust removal, cleaning abrasive and rust slag after spraying a certain section, marking cracks, welding seams and severe corrosion positions, carrying out paint spraying on the next step to prevent the inner surface of the steel box from being corroded again, and repairing the defect position after the paint is dried completely. The invention combines the conventional structure of the existing steel box girder, provides different maintenance and reconstruction construction processes according to different defects of the steel box girder, provides a set of complete construction method for reinforcing the steel box girder, provides reference for similar projects, and has extremely high popularization value.)

1. The integral maintenance and reinforcement construction method for the orthotropic plate steel box girder of the cable-stayed bridge is characterized by comprising the following steps of:

selecting whether to carry out sand blasting derusting and/or recoating according to the peeling and rusting conditions of paint on the surface of the steel box girder structure;

selecting whether to replace the bolts and/or the connecting plates according to the corrosion conditions of the connecting plates and the connecting bolts connected with the orthotropic bridge deck;

selecting whether to perform weld joint removal and re-welding according to the cracking condition of the weld joints of the transverse ribs and the U ribs, additionally arranging a folded plate for reinforcement, selecting whether to perform weld joint re-welding according to the corrosion condition of the weld joints of the bottom plate and the outer web of the steel box girder, and if so, sealing the fillet weld joints by using polysulfide anticorrosive sealant;

the U-rib cover plate is selected to be cut off according to the welding and falling conditions of the U-rib cover plate, and if the U-rib cover plate is cut off, a new U-rib cover plate is bolted by adopting a high-strength bolt;

selecting whether to remove rust again according to the corrosion condition of the bottom plate of the steel box girder, and if the rust is removed again, adopting a steel plate bolt for reinforcement;

and selecting whether to carry out crack stop hole drilling according to the crack condition of the steel box girder, and adding two clamping plates for bolting and reinforcing if the crack stop hole drilling is carried out.

2. The cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method according to claim 1, wherein the integral construction sequence comprises the following steps: carrying out sand blasting and rust removal, cleaning abrasive and rust slag after spraying a certain section, marking cracks, welding seams and severe corrosion positions, carrying out paint spraying on the next step to prevent the inner surface of the steel box from being corroded again, and repairing the defect position after the paint is dried completely.

3. The method for integrally maintaining, reinforcing and constructing the orthotropic plate steel box girder of the cable-stayed bridge according to claim 1, wherein the method for maintaining the U rib comprises the following steps: replacement of the U-rib cover plate, reinforcement of the U-rib butt joint transverse seam, and reinforcement of the weld joint of the U-rib and the box girder connecting part.

4. The cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method according to claim 3, wherein the method for replacing the U-rib cover plate comprises the following steps:

s1: cutting an original U-shaped rib cover plate: cutting along the connecting position of the U-rib cover plate and the U rib by using a plasma cutting machine, then cutting along the connecting welding seam of the U-rib cover plate and the top bottom plate, and cleaning and polishing the cutting residual height and the cutting surface by using an air gouging and a grinding wheel after the U-rib cover plate is cut off;

s2, cleaning the connecting surface to construct an anti-skid coating layer: cleaning edges and corners of the drilled holes and the cut edges, polishing, after a row of U rib cover plates are completely disassembled, intensively adopting a sand blasting machine to perform sand blasting and rust removal on the friction surfaces of the original U ribs, and then spraying anti-skid paint;

s3, temporarily positioning and fixing the U-rib cover plate mother board: two bolt holes are formed in two sides below the U rib, holes are drilled in the U rib in advance according to the distance, and a U rib cover plate is directly bolted to the U rib;

s4, connecting bolt hole sleeve drilling and construction hand hole drilling: after the U-rib cover plate is temporarily fixed, construction of a connecting bolt hole and a construction hand hole is carried out, the U-rib connecting bolt adopts a large hexagonal high-strength bolt, and then construction is carried out through a magnetic drill;

s5, high-strength bolt screwing and U-rib cover plate welding: utilize interim connecting bolt and towards the counterpoint of nail carrying out the hole site during the construction of U rib apron, ensure that every bolt hole bolt can both smoothly penetrate the back, carry out the construction that penetrates of high-strength bolt, the construction of high-strength bolt is according to the order construction of twisting first and twisting last, adopt the electric spanner through the check-up to twist the bolt to twist 50% of the moment of torsion of twisting last, the order of twisting of exerting of bolt is around the center earlier, carry out welding construction, adopt carbon dioxide gas shielded welding to the connecting weld of U rib apron top and girder steel after the bolt construction is accomplished.

5. The method for integrally maintaining, reinforcing and constructing the orthotropic plate steel box girder of the cable-stayed bridge according to claim 3, wherein the method for reinforcing the butt joint transverse seam of the U rib comprises the following steps: polishing original welding seams, covering by a U-rib cover plate with proper length after removing rust slag, and connecting and fixing the U-rib cover plate with the original U-ribs by bolts, wherein the construction flow is as follows:

s11: drilling a bolt hole and a hand hole in the master plate;

s12: polishing and repairing welding seams: after the drilling construction is finished, cleaning corners of bolt holes and hand holes, polishing the welding seams by using an angle grinder or an air gouging machine, removing rust slag and polishing smoothly, re-welding the welding seams after polishing is finished, welding by using carbon dioxide gas shielded welding, performing ultrasonic flaw detection on the welding seams according to the standard requirement after the welding seams are welded, and performing secondary treatment on the welding seams with problems;

s13: connecting surface treatment: after welding, performing sand blasting and rust removal on the connecting surface and anti-skid coating construction;

s14: and (5) cover plate construction.

6. The method for integrally maintaining, reinforcing and constructing the orthotropic plate steel box girder of the cable-stayed bridge according to claim 3, wherein the method for reinforcing the welding seam of the connecting part of the U rib and the box girder comprises the following steps: the fracture welding seam of polishing and repair welding need utilize L shape steel sheet to carry out the reinforcement to the welding seam that welding seam fracture length is greater than 10cm, and reinforcement length is decided according to the length of welding seam fracture to cover the full length of welding seam, consolidate the steel sheet and adopt high-strength bolted connection with the U rib, the construction process is:

s21: checking and accepting repair welding seams;

s22: pre-mounting a bevel steel plate;

s23: punching bolt holes and opening hand holes;

s24: spraying inorganic zinc-rich anti-skid paint;

s25: and bolting the reinforced bevel steel plate.

7. The method for integrally maintaining, reinforcing and constructing the orthotropic plate steel box girder of the cable-stayed bridge according to claim 1, wherein the method for maintaining and reinforcing the gusset plate comprises the following steps:

the bolt and the connecting batten plate are in good condition and slightly rusted, and are subjected to sand blasting removal and anticorrosive coating treatment together with the steel box girder;

if the single bolt and the connecting batten plate are rusted heavily, the connecting batten plate and the corresponding bolt are replaced together;

if the bolts and the connecting batten plates are corroded at multiple positions or the whole body, all the exposed connecting batten plates and the corresponding bolts are replaced together;

after rust removal, the damage thickness of the long connecting plate on the outer side of the steel box girder exceeds 25%, replacement is needed, corresponding U ribs in the steel box girder are cut off, and meanwhile, the long connecting steel plate is replaced in a blocking and sectional manner;

the connecting bolts of all gusset plates are replaced on the top plate of the steel box girder, and the side of the bolt and the nut face downwards;

when gaps exist at the splicing positions of the original bridge deck plates, all the gaps are sealed by welding.

8. The cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method according to claim 7, wherein the gusset plate replacement construction process flow comprises the following steps:

s31: dismantling the high-strength bolts and the gusset plates: removing the materials one by one from the periphery to the middle;

s32: performing sand blasting treatment on the base material: after the gusset plate is removed, firstly, checking the hole diameter and the hole pitch size of a bolt hole, and then, carrying out local sand blasting treatment on a friction surface of a base metal;

s33: spraying inorganic zinc-rich anti-skid coating on parent metal: dedusting the painted part by using high-pressure air of an air compressor, and coating the inorganic zinc-rich anti-skid paint;

s34: installing a gusset plate: after the anti-skid paint is dried, the hole sites at the four corners of the connecting plate are aligned by using the punching nails;

s35: installing a node bolt: carrying out initial screwing on the high-strength bolt by using a torque wrench, wherein the initial screwing torque is 50% of the final screwing torque in construction, carrying out initial screwing from inside to outside of a bolt group, and marking colors on a nut diagram after the initial screwing to prevent the missing screwing;

s36: and (3) final screwing of the high-strength bolt: and after the initial screwing is finished, final screwing is carried out according to the initial screwing, and color marking is carried out after the final screwing, so that the bolts are completely screwed.

9. The cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method according to claim 1, wherein the bottom plate corrosion maintenance and reinforcement method comprises the following steps: a drainage hole is formed in the bottom plate by a magnetic drill, a plastic pipe is additionally arranged to extend out of the bottom plate of the box girder, the bottom plate is prevented from being corroded by flowing water along the hole, then a defective welding seam is subjected to repair welding, then MF860F polysulfide anticorrosion sealant is used for sealing treatment, and a layer of epoxy zinc-rich primer is coated on the surface of the steel plate before the sealant is embedded.

10. The cable-stayed bridge orthotropic plate steel box girder integral maintenance and reinforcement construction method according to claim 1, wherein the transverse rib crack maintenance and reinforcement method comprises the following steps:

treating the disease with crack length less than 10 mm;

the crack length is more than 10mm, but the length is less than 50mm, and the crack stop hole is additionally arranged at the tip of the crack to prevent the crack from further developing;

the length of the crack is more than 50mm, and the steel plate is additionally arranged after the crack stopping hole is additionally arranged at the tip of the crack for reinforcement.

Technical Field

The invention relates to the technical field of building construction, in particular to an integral maintenance and reinforcement construction method for an orthotropic plate steel box girder of a cable-stayed bridge.

Background

The steel box girder structure is composed of a series of components such as a top plate, a bottom plate, a web plate, a longitudinal stiffening rib, a transverse stiffening rib, a vertical stiffening rib and the like, and all the components can be connected by using a welding process. Because the steel box girder has a plurality of welding parts and complex stress, the steel box girder always bears the repeated action of wheel load, and the uncertainty factors of the welding process are numerous, the welding seam can have a series of influences such as welding residual stress and the like, and the welding seam of the steel box girder often becomes the part of the structure which is most easy to crack and has faster crack development. On the other hand, the generation and development of the fatigue cracking of the steel box girder are also aggravated by large-flow and heavy-load traffic, and particularly the heavy traffic which plays a leading role in fatigue damage is greatly increased, so that the bridge adopting the section form of the steel box girder becomes a serious disaster area of the fatigue cracking of steel.

However, a systematic maintenance and reconstruction construction process does not exist for the maintenance and reconstruction of the steel box girder bridge, most of the maintenance and reinforcement of the stayed-cable steel box girder bridge mainly repairs the welding seams and the beam cracks, and a set of universal maintenance and reconstruction construction process is urgently needed for the reference of similar engineering in the future.

Disclosure of Invention

In order to solve the problems in the prior art, the method for integrally maintaining and reinforcing the orthotropic plate steel box girder of the cable-stayed bridge is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the invention provides an integral maintenance and reinforcement construction method for orthotropic plate steel box girders of a cable-stayed bridge, which comprises the following steps:

selecting whether to carry out sand blasting derusting and/or recoating according to the peeling and rusting conditions of paint on the surface of the steel box girder structure;

selecting whether to replace the bolts and/or the connecting plates according to the corrosion conditions of the connecting plates and the connecting bolts connected with the orthotropic bridge deck;

selecting whether to perform weld joint removal and re-welding according to the cracking condition of the weld joints of the transverse ribs and the U ribs, additionally arranging a folded plate for reinforcement, selecting whether to perform weld joint re-welding according to the corrosion condition of the weld joints of the bottom plate and the outer web of the steel box girder, and if so, sealing the fillet weld joints by using polysulfide anticorrosive sealant;

the U-rib cover plate is selected to be cut off according to the welding and falling conditions of the U-rib cover plate, and if the U-rib cover plate is cut off, a new U-rib cover plate is bolted by adopting a high-strength bolt;

selecting whether to remove rust again according to the corrosion condition of the bottom plate of the steel box girder, and if the rust is removed again, adopting a steel plate bolt for reinforcement;

and selecting whether to carry out crack stop hole drilling according to the crack condition of the steel box girder, and adding two clamping plates for bolting and reinforcing if the crack stop hole drilling is carried out.

Preferably, the overall construction sequence comprises: carrying out sand blasting and rust removal, cleaning abrasive and rust slag after spraying a certain section, marking cracks, welding seams and severe corrosion positions, carrying out paint spraying on the next step to prevent the inner surface of the steel box from being corroded again, and repairing the defect position after the paint is dried completely.

Preferably, the method for repairing the U-rib includes: replacement of the U-rib cover plate, reinforcement of the U-rib butt joint transverse seam, and reinforcement of the weld joint of the U-rib and the box girder connecting part.

Preferably, the method for replacing the U-rib cover plate includes:

s1: cutting an original U-shaped rib cover plate: cutting along the connecting position of the U-rib cover plate and the U rib by using a plasma cutting machine, then cutting along the connecting welding seam of the U-rib cover plate and the top bottom plate, and cleaning and polishing the cutting residual height and the cutting surface by using an air gouging and a grinding wheel after the U-rib cover plate is cut off;

s2, cleaning the connecting surface to construct an anti-skid coating layer: cleaning edges and corners of the drilled holes and the cut edges, polishing, after a row of U rib cover plates are completely disassembled, intensively adopting a sand blasting machine to perform sand blasting and rust removal on the friction surfaces of the original U ribs, and then spraying anti-skid paint;

s3, temporarily positioning and fixing the U-rib cover plate mother board: two bolt holes are formed in two sides below the U rib, holes are drilled in the U rib in advance according to the distance, and a U rib cover plate is directly bolted to the U rib;

s4, connecting bolt hole sleeve drilling and construction hand hole drilling: after the U-rib cover plate is temporarily fixed, construction of a connecting bolt hole and a construction hand hole is carried out, the U-rib connecting bolt adopts a large hexagonal high-strength bolt, and then construction is carried out through a magnetic drill;

s5, high-strength bolt screwing and U-rib cover plate welding: utilize interim connecting bolt and towards the counterpoint of nail carrying out the hole site during the construction of U rib apron, ensure that every bolt hole bolt can both smoothly penetrate the back, carry out the construction that penetrates of high-strength bolt, the construction of high-strength bolt is according to the order construction of twisting first and twisting last, adopt the electric spanner through the check-up to twist the bolt to twist 50% of the moment of torsion of twisting last, the order of twisting of exerting of bolt is around the center earlier, carry out welding construction, adopt carbon dioxide gas shielded welding to the connecting weld of U rib apron top and girder steel after the bolt construction is accomplished.

Preferably, the method for reinforcing the butt-joint transverse seam of the U rib comprises the following steps: polishing original welding seams, covering by a U-rib cover plate with proper length after removing rust slag, and connecting and fixing the U-rib cover plate with the original U-ribs by bolts, wherein the construction flow is as follows:

s11: drilling a bolt hole and a hand hole in the master plate;

s12: polishing and repairing welding seams: after the drilling construction is finished, cleaning corners of bolt holes and hand holes, polishing the welding seams by using an angle grinder or an air gouging machine, removing rust slag and polishing smoothly, re-welding the welding seams after polishing is finished, welding by using carbon dioxide gas shielded welding, performing ultrasonic flaw detection on the welding seams according to the standard requirement after the welding seams are welded, and performing secondary treatment on the welding seams with problems;

s13: connecting surface treatment: after welding, performing sand blasting and rust removal on the connecting surface and anti-skid coating construction;

s14: and (5) cover plate construction.

Preferably, the method for reinforcing the weld of the joint of the U rib and the box girder comprises the following steps: the fracture welding seam of polishing and repair welding need utilize L shape steel sheet to carry out the reinforcement to the welding seam that welding seam fracture length is greater than 10cm, and reinforcement length is decided according to the length of welding seam fracture to cover the full length of welding seam, consolidate the steel sheet and adopt high-strength bolted connection with the U rib, the construction process is:

s21: checking and accepting repair welding seams;

s22: pre-mounting a bevel steel plate;

s23: punching bolt holes and opening hand holes;

s24: spraying inorganic zinc-rich anti-skid paint;

s25: and bolting the reinforced bevel steel plate.

Preferably, the repair reinforcement method for the gusset plate includes:

the bolt and the connecting batten plate are in good condition and slightly rusted, and are subjected to sand blasting removal and anticorrosive coating treatment together with the steel box girder;

if the single bolt and the connecting batten plate are rusted heavily, the connecting batten plate and the corresponding bolt are replaced together;

if the bolts and the connecting batten plates are corroded at multiple positions or the whole body, all the exposed connecting batten plates and the corresponding bolts are replaced together;

after rust removal, the damage thickness of the long connecting plate on the outer side of the steel box girder exceeds 25%, replacement is needed, corresponding U ribs in the steel box girder are cut off, and meanwhile, the long connecting steel plate is replaced in a blocking and sectional manner;

the connecting bolts of all gusset plates are replaced on the top plate of the steel box girder, and the side of the bolt and the nut face downwards;

when gaps exist at the splicing positions of the original bridge deck plates, all the gaps are sealed by welding.

Preferably, the gusset plate replacement construction process flow comprises:

s31: dismantling the high-strength bolts and the gusset plates: removing the materials one by one from the periphery to the middle;

s32: performing sand blasting treatment on the base material: after the gusset plate is removed, firstly, checking the hole diameter and the hole pitch size of a bolt hole, and then, carrying out local sand blasting treatment on a friction surface of a base metal;

s33: spraying inorganic zinc-rich anti-skid coating on parent metal: dedusting the painted part by using high-pressure air of an air compressor, and coating the inorganic zinc-rich anti-skid paint;

s34: installing a gusset plate: after the anti-skid paint is dried, the hole sites at the four corners of the connecting plate are aligned by using the punching nails;

s35: installing a node bolt: carrying out initial screwing on the high-strength bolt by using a torque wrench, wherein the initial screwing torque is 50% of the final screwing torque in construction, carrying out initial screwing from inside to outside of a bolt group, and marking colors on a nut diagram after the initial screwing to prevent the missing screwing;

s36: and (3) final screwing of the high-strength bolt: and after the initial screwing is finished, final screwing is carried out according to the initial screwing, and color marking is carried out after the final screwing, so that the bolts are completely screwed.

Preferably, the method for repairing and reinforcing the corrosion of the bottom plate comprises the following steps: a drainage hole is formed in the bottom plate by a magnetic drill, a plastic pipe is additionally arranged to extend out of the bottom plate of the box girder, the bottom plate is prevented from being corroded by flowing water along the hole, then a defective welding seam is subjected to repair welding, then MF860F polysulfide anticorrosion sealant is used for sealing treatment, and a layer of epoxy zinc-rich primer is coated on the surface of the steel plate before the sealant is embedded.

Preferably, the transverse rib crack repair and reinforcement method comprises the following steps:

treating the disease with crack length less than 10 mm;

and a crack stop hole is additionally arranged at the tip of the crack to prevent the crack from further developing, wherein the length of the crack is more than 10mm, but the length of the crack is less than 50 mm.

The length of the crack is more than 50mm, and the steel plate is additionally arranged after the crack stopping hole is additionally arranged at the tip of the crack for reinforcement.

Compared with the prior art, the invention has the beneficial effects that:

the invention combines the conventional structure of the existing steel box girder, provides different maintenance and reconstruction construction processes according to different defects of the steel box girder, provides a set of complete construction method for reinforcing the steel box girder, provides reference for similar projects, greatly improves the integral fatigue resistance of the steel box girder, effectively prolongs the service life of the steel box girder and has extremely high popularization value.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural view of a steel box girder according to the present invention;

FIG. 2 is a layout view of ventilation and illumination for work in a steel box according to the present invention;

FIG. 3 is a design view of the U-ribbed cover plate of the present invention;

FIG. 4 is a schematic view of the U-ribbed cover plate of the present invention;

FIG. 5 is a schematic view of the U-rib weld reinforcement of the present invention;

FIG. 6 is a schematic elevation view of the reinforcement of the bottom plate of the steel box girder in the present invention;

FIG. 7 is a schematic plan view of the reinforcement of the bottom plate of the steel box girder in the present invention;

FIG. 8 is a schematic view of the weld joint processing between the bottom plate and the outer web of the steel box girder according to the present invention.

Description of reference numerals:

1 an orthotropic deck plate; 2U ribs; a 21U rib cover plate; 3, connecting a plate; 4, a steel box girder bottom plate; 5, in a steel box; 6 outer web.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As shown in fig. 1-8, the embodiment proposes an integral maintenance and reinforcement construction method for orthotropic steel plate box girder of cable-stayed bridge,

selecting whether to carry out sand blasting derusting and/or recoating according to the peeling and rusting conditions of paint on the surface of the steel box girder structure;

selecting whether to replace the bolts and/or the connecting plates according to the corrosion conditions of the connecting plates and the connecting bolts connected with the orthotropic bridge deck;

selecting whether to perform weld joint removal and re-welding according to the cracking condition of the weld joints of the transverse ribs and the U ribs, additionally arranging a folded plate for reinforcement, selecting whether to perform weld joint re-welding according to the corrosion condition of the weld joints of the bottom plate and the outer web of the steel box girder, and if so, sealing the fillet weld joints by using polysulfide anticorrosive sealant;

the U-rib cover plate is selected to be cut off according to the welding and falling conditions of the U-rib cover plate, and if the U-rib cover plate is cut off, a new U-rib cover plate is bolted by adopting a high-strength bolt;

selecting whether to remove rust again according to the corrosion condition of the bottom plate of the steel box girder, and if the rust is removed again, adopting a steel plate bolt for reinforcement;

and selecting whether to carry out crack stop hole drilling according to the crack condition of the steel box girder, and adding two clamping plates for bolting and reinforcing if the crack stop hole drilling is carried out.

The integral sand blasting rust removal and recoating are adopted for large-area corrosion aiming at the paint peeling of the surface of the steel box girder structure;

aiming at the connection plate 3 and a large amount of connecting bolts connected with the orthotropic bridge deck 1, the bolts are completely replaced, and the connection plate 3 is completely replaced when being seriously corroded;

aiming at the weld joint cracking of the transverse rib and the U rib 2, adopting weld joint planing and re-welding, additionally arranging a folded angle plate for reinforcement, aiming at the weld joint corrosion of the steel box girder bottom plate and the outer web 6, adopting weld joint re-welding, and sealing the angle weld joint by polysulfide anticorrosion sealant, wherein the U rib 2 also comprises a U rib cover plate 21;

aiming at the welding and falling of the U-rib cover plate 21, the U-rib cover plate 21 in all welding forms of full bridge is cut off, and a new U-rib cover plate 21 is bolted by adopting a high-strength bolt;

aiming at the serious corrosion of the bottom plate 4 of the steel box girder, the steel plate is added for bolting reinforcement after rust removal is carried out again;

and aiming at all the beam cracks of the steel box beam, crack stop holes are drilled, and two clamping plates are additionally arranged for bolting and reinforcing.

The maintenance and transformation of the orthogonal special-shaped plate steel box girder of the cable-stayed bridge is integrally constructed by three parts:

the inside of the steel box on two sides is partially unfolded firstly, the outside of the steel box girder and the lower part of the bridge deck are unfolded simultaneously, and finally the bridge deck is partially constructed.

As shown in figure 2, the steel box inner 5 belongs to closed space operation, lighting and ventilation measures are needed, 100W lighting explosion-proof running lights are hung on two sides of a construction part to provide lighting during actual operation, axial fans are arranged on a man hole and the left side and the right side of an operation surface to form air circulation, and the air circulation is propelled along with the operation surface.

The external part of the steel box girder and the lower part of the bridge deck slab belong to aerial work, and the maintenance trolleys can be erected by using the construction platform under the bridge, two maintenance trolleys are erected below each span, and four maintenance trolleys are erected on the main span. The maintenance trolley can move longitudinally along with the operation surface, and is fixed and provided with a disc buckle support when being constructed at a specific position.

The whole construction sequence is as follows: carrying out sand blasting and rust removing, cleaning abrasive and rust slag after spraying a certain section, marking cracks, welding seams and severe corrosion positions, carrying out paint spraying on the next step, preventing the inner surface of the steel box from being corroded again, and avoiding simultaneous paint operation and sand blasting operation to prevent the influence of sand blasting on the paint spraying quality. And repairing the defect position after the paint is dried, and aiming at different types of diseases, the reinforcing mode and the process are as follows.

The maintenance method of the U rib 2 comprises the following steps: replacement of the U-rib cover plate 21, reinforcement of a butt joint transverse seam of the U rib 2, and reinforcement of a welding seam at a connecting part of the U rib 2 and the box girder. Corresponding reinforcement measures are carried out according to different diseases

When carrying out the bridge floor design usually, for at case roof beam butt joint connecting plate bolt position, adopt U rib apron 21 welded connection, along with the long-time application of bridge floor, current U rib apron 21 has the phenomenon that the corrosion ftractures, drops. This maintenance is consolidated and is demolishd the U rib apron 21 of renewal to the U rib apron 21 of welding form, uses the high-strength bolt to connect fixedly simultaneously in order to guarantee that U rib apron 21 and former U rib 2 are connected reliably.

The method for replacing the U-rib cover plate 21 comprises the following steps:

s1: cutting an original U-shaped rib cover plate: cutting along the connecting position of the U-rib cover plate 21 and the U rib 2 by adopting a plasma cutting machine, then cutting along the connecting welding seam of the U-rib cover plate 21 and the top bottom plate, and cleaning and polishing the cutting surplus height and the cutting surface by utilizing an air plane and a grinding wheel after the U-rib cover plate 21 is cut off, so as to ensure that the section surface is smooth and has no sharp-angled convex edge;

s2, cleaning the connecting surface to construct an anti-skid coating layer: and (4) cleaning edges and corners of the drilled holes and the cut edges and polishing to ensure good adhesion of anticorrosive coating. After the row of U-rib cover plates 21 are completely disassembled, sand blasting and rust removing are carried out on the original U-rib friction surfaces by intensively adopting a sand blasting machine, then anti-skid paint is sprayed, the friction force of the U-rib cover plates 21 is enhanced, and the shearing resistance of the high-strength bolt is optimal;

s3: temporarily positioning and fixing a U-rib cover plate mother plate: the length of the U rib processed in the example is 1.37m, in order to ensure that a U rib cover plate can be temporarily fixed at the central position of the U rib connection, two bolt holes are formed in two sides below the U rib, holes are drilled on the U rib in advance according to the distance, and the U rib cover plate is directly bolted on the U rib, so that the positioning accuracy is ensured, and the construction efficiency is also ensured;

s4: drilling and opening construction hand holes in the connecting bolt holes: and after the U-rib cover plate is temporarily fixed, the construction of a connecting bolt hole and a construction hand hole is carried out, the U-rib connecting bolt is a large hexagonal high-strength bolt with the diameter of 22mm, the diameter of the bolt hole is 24mm, and the construction is carried out by adopting magnetic drilling. In consideration of the problem of the construction space of the U-shaped rib, a horizontal magnetic drill is adopted, the height of the magnetic drill is 20cm, the length of the magnetic drill is 23cm, and the width of the magnetic drill is 10cm in the example so as to meet the construction requirements. Cutting the construction hand hole by using a plasma cutting machine according to the size of the construction hand hole on the master plate;

s5: screwing high-strength bolts and welding U-rib cover plates: utilize interim connecting bolt and punching pin to carry out the counterpoint of hole site during the construction of U rib apron, ensure that every bolt hole bolt can both smoothly penetrate the back, carry out the construction that penetrates of high-strength bolt. The construction of the high-strength bolt is carried out according to the sequence of initial screwing and final screwing, the bolt is screwed to 50% of the final screwing torque by adopting a verified electric wrench, the screwing sequence of the bolt is firstly central and then peripheral, and for the high-strength bolt after initial screwing, a straight line is drawn on a nut, a gasket and a plate surface by using a white board pen immediately so as to prevent repeated screwing, omission and convenience in inspection. And after the bolt construction is finished, welding construction is carried out on the connecting welding line of the top of the U-shaped rib cover plate and the steel beam, carbon dioxide gas is adopted for protection welding, and the height of the welding line is 6 mm.

The U-rib butt joint transverse seam reinforcing method comprises the following steps: and grinding the original welding line, removing rust slag, covering by using a U-rib cover plate 21 with proper length, and connecting and fixing with the original U-rib connecting plate 2 by using bolts. In general, the U-rib butt welds adopt butt welds except for nodes, and the problem of weld cracking often occurs. The treatment mode for the diseases is as follows: and polishing the original welding line, removing rust slag, covering by using a U-rib cover plate with the length of 340cm, and connecting and fixing the U-rib cover plate with the original U-rib through bolts.

The construction process comprises the following steps:

s11: drilling a bolt hole and a hand hole in the master plate;

s12: polishing and repairing welding seams: after the drilling construction is finished, cleaning corners of bolt holes and hand holes, polishing the welding seams by using an angle grinder or an air gouging machine, removing rust slag and polishing smoothly, re-welding the welding seams after polishing is finished, welding by using carbon dioxide gas shielded welding, performing ultrasonic flaw detection on the welding seams according to the standard requirement after the welding seams are welded, and performing secondary treatment on the welding seams with problems;

s13: connecting surface treatment: after welding, performing sand blasting and rust removal on the connecting surface and anti-skid coating construction;

s14: and (5) cover plate construction.

Usually, the connection of the original U-shaped rib and the top (bottom) plate and the transverse rib of the steel beam is welded, and the problem of weld cracking exists. The method for reinforcing the welding seam of the connecting part of the U rib 2 and the box girder comprises the following steps: the fracture welding seam of polishing and repair welding need utilize L shape steel sheet to carry out the reinforcement to the welding seam that welding seam fracture length is greater than 10cm, and reinforcement length is decided according to the length of welding seam fracture to cover the full length of welding seam, consolidate the steel sheet and adopt high-strength bolted connection with the U rib, the construction process is:

s21: checking and accepting repair welding seams;

s22: pre-mounting a bevel steel plate;

s23: punching bolt holes and opening hand holes;

s24: spraying inorganic zinc-rich anti-skid paint;

s25: and bolting the reinforced bevel steel plate.

The U-shaped ribs of the top and bottom plates are the same in size and similar reinforcing methods are adopted, and the top plate is taken as an example here to describe the reinforcing method of the steel plate.

The reinforced steel plate is processed according to the size scale measured in advance on site, the length is the crack length +150mm, the repair welding seam can be covered by the reinforced steel plate, so that the cross section of the position can be effectively enhanced, and the follow-up cracking risk is reduced.

The maintenance and reinforcement method of the gusset plate comprises the following steps:

the maintenance of case roof beam connecting plate is consolidated and is adopted different processing scheme according to the corrosion degree:

(1) the bolt and the connecting batten plate are in good condition and slightly rusted, and are subjected to sand blasting removal and anticorrosive coating treatment together with the box girder;

(2) if the single bolt and the connecting batten plate are rusted heavily, the connecting batten plate and the corresponding bolt are replaced together;

(3) if the bolts and the connecting batten plates are corroded at multiple positions or the whole body, all the exposed connecting batten plates and the corresponding bolts are replaced together;

(4) the long connecting plate on the outer side of the steel beam is not replaced in principle, the long connecting plate still has serious damage after rust removal under special conditions, the damage thickness exceeds 25%, and when the long connecting plate needs to be replaced, corresponding U ribs in the box beam need to be cut off. Meanwhile, the long connecting steel plate is required to be replaced in blocks and sections, and the replacement implementation scheme and steps are determined after field detection;

(5) specially, the connecting bolts of all the batten plates are replaced on the steel beam top plate, and the side of the bolt and the nut face downwards;

(6) the intersection of the transverse joint and the longitudinal joint of the bridge is not replaced unless the corrosion is serious;

(7) gaps exist in the splicing positions of the original bridge panels locally, so that water easily enters the box chamber, and all the gaps need to be sealed by welding.

The gusset plate replacement construction process flow comprises the following steps:

and (3) aiming at the parts of the top and bottom plate gusset plates and the bolts which are all required to be replaced, replacing and constructing according to the construction process of high-strength bolts and connecting plates dismantling → local sand blasting of parent metal → spraying of inorganic zinc-rich anti-skid coating → installation of steel plates and high-strength bolts. Because the gusset plates at the lower part of the top plate need to be completely replaced and cannot be completely removed at one time, the gusset plates at the positions of the U-rib-free cover plates are replaced firstly, and the gusset plates at the positions of the U-rib-free cover plates are integrally replaced after all the gusset plates are completely twisted.

S31: dismantling the high-strength bolts and the gusset plates: and removing the materials one by one from the periphery to the middle. Arranging personnel to drag the steel plate before the last four bolts are removed to prevent falling and smashing injuries;

s32: performing sand blasting treatment on the base material: after the gusset plate is removed, firstly, checking the aperture and pitch size of a bolt hole, wherein the hole edge is smooth and has no burr, then, carrying out local sand blasting treatment on the friction surface of the base material, and checking and accepting the finish and roughness of the base material after the sand blasting is finished;

s33: spraying inorganic zinc-rich anti-skid coating on parent metal: the base material smoothness and the roughness of the installation position of the gusset plate meet the requirements after inspection, the dust of a paint spraying part is removed by using high-pressure air of an air compressor, and the inorganic zinc-rich anti-skid paint is coated;

s34: installing a gusset plate: after the anti-skid paint is dried, firstly, the punching nails are used for aligning the hole sites at the four corners of the connecting plate to ensure the mounting precision, and temporary bolts and punching nails are used for ensuring the mounting precision and safety;

s35: installing a node bolt: and (3) primarily screwing the high-strength bolt by using a torque wrench, wherein the initial screwing torque is 50% of the final screwing torque of construction. In order to enable the bolt group to be stressed uniformly, the bolt group is initially screwed from inside to outside, and the color of the nut graph is marked after the initial screwing to prevent the screw from being missed;

s36: and (3) final screwing of the high-strength bolt: and after the initial screwing is finished, final screwing is carried out according to the initial screwing, and color marking is carried out after the final screwing, so that the bolts are completely screwed.

The final torque value is calculated as: tc ═ kPcd ═ 0.130 ═ 210 ═ 22 ═ 600.6N · m, the average torque coefficient was taken as 0.130, and the data was corrected accordingly based on the measured torque coefficient average for each batch of bolts.

The bottom plate corrosion maintenance and reinforcement method comprises the following steps:

because the incasement often can have into water the condition, case roof beam bottom plate department ponding is serious, under the long-term ponding soaking effect, roof beam bottom plate department corrosion is more serious, to the bottom plate section loss rate over 20% and above position, carries out the bottom plate reinforcement.

The box girder bottom plate reinforcement is similar to the construction process of gusset plate installation, and the difference lies in that the bottom plate needs to be perforated and subjected to rust removal before the reinforcing steel plate is installed. Sand blasting and rust removing → bolt hole opening → spraying inorganic zinc-rich anti-skid coating → bolting and reinforcing steel plates.

The bottom plate is provided with a drainage hole: aiming at the phenomenon of water accumulation of the bottom plate, the bottom plate at the position covered by the full-bridge U-shaped rib is designed to be punched.

The water drainage hole is drilled on the bottom plate by the magnetic drill, the length of the segment is smaller than or equal to 1100mm, holes are drilled in two sides and the middle of the bottom plate respectively, the length of the segment is larger than 1100mm, the diameter of the single hole is 15mm, the hole edge is smooth and smooth, and the plastic pipe is additionally arranged to extend out of the bottom plate of the box beam to prevent flowing water from corroding the bottom plate along the hole.

The joint of the outer web plate of the box girder and the bottom plate is processed: besides the need of repair welding of the welding seam with defects, the sealing treatment is also carried out by using MF860F polysulfide anticorrosion sealant. Before embedding and filling the sealant, coating a layer of epoxy zinc-rich primer on the surface of the steel plate, embedding and filling by using a glue injection gun and a scraper, firstly filling by using the glue injection gun, taking the sealant as the standard for completely covering the welding seam and the exposed part of the bottom plate, upwards covering by 3cm along the outer web 6, wherein the maximum thickness is not more than 3cm, and then shaping by using the scraper to improve the finish degree of the glue surface and the compactness of the glue. And finally, curing, namely, after the sealing glue is completely filled, covering the sealing glue with tarpaulin to prevent the sealing glue from being polluted by insolation, rain and other substances, wherein the curing time is 2-3 days.

The transverse rib crack repairing and reinforcing method comprises the following steps:

(1) treating the disease with crack length less than 10 mm;

(2) and a crack stop hole is additionally arranged at the tip of the crack to prevent the crack from further developing, wherein the length of the crack is more than 10mm, but the length of the crack is less than 50 mm.

(3) The length of the crack is more than 50mm, and the steel plate is additionally arranged after the crack stopping hole is additionally arranged at the tip of the crack for reinforcement.

Drilling a crack-stopping hole: and (3) drilling a crack stopping hole with the aperture of 10mm and the center distance of 20mm from the crack tip in the front of the crack tip development direction by adopting a magnetic drill, and marking the hole opening point according to the crack condition and the development trend after the sand blasting is finished.

Adding a reinforcing steel plate: and at the position where the length of the crack is more than 50mm, not only the crack-stopping hole needs to be drilled according to the requirements, but also a reinforced steel plate with a corresponding size is configured according to the crack condition, and the steel plate is required to completely cover the crack and the crack-stopping hole.

The invention relates to treatment of all common diseases on a steel box girder, and the method can treat the common diseases in maintenance engineering of the orthogonal special-shaped plate steel box girder of a cable-stayed bridge, and comprehensively considers various factors such as construction feasibility, efficiency, cost and the like from an actual project to obtain an actual treatment scheme and a construction process through comprehensive arrangement.

In addition, the gusset plate and the U-rib cover plate 21 under the bridge deck plate need to be completely replaced, but in order to prevent the spliced position from deforming, the U-rib cover plate 21 needs to be removed at intervals, the position gusset plate of the U-rib cover plate 21 is replaced and finally twisted, then the U-rib cover plate 21 is removed, the gusset plate at the position of the U-rib cover plate 21 is replaced, and finally a new U-rib cover plate 21 is installed.

Meanwhile, for the position of the connecting plate 3 needing to be replaced with a new connecting plate or the position of the reinforcing steel plate needing to be added, the friction force and the anti-sliding performance between the new steel plate and the original bridge steel plate need to be enhanced, firstly, sand blasting is carried out to remove rust and old coatings, then, anti-sliding coatings are sprayed, and finally, the new connecting plate 3 is installed.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.