A reinforcement structure for fatigue cracked steel bridge deck

Abstract

A reinforcement structure for a fatigue-cracked steel bridge deck, the main points of its technical solution are: it includes a cracked steel bridge deck, carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh, an ultra-high performance concrete layer and a wear layer, carbon fiber reinforced slats are arranged on the cracked steel deck, shear connectors are welded to the metal reinforced slats, the metal reinforced slats with shear connectors are arranged above the carbon fiber reinforced slats, the steel mesh is placed on the cracked steel bridge deck, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with carbon fiber reinforced slats, metal reinforced slats, shear connectors, and steel mesh and connected to the cracked steel bridge deck, and the wear layer covers the top surface of the ultra-high performance concrete layer.

Description

Technical Field

[0001] The invention relates to a bridge structure for reinforcing orthotropic steel bridge decks, in particular to a reinforcement structure for fatigue cracked steel bridge decks. Background Art

[0002] Since its introduction, orthotropic steel bridge decks have been favored by bridge designers for their light weight, high ultimate bearing capacity, fast construction, and elegant design, making them particularly suitable for long-span bridges. However, the low local stiffness of steel bridge decks makes them susceptible to fatigue cracking during long-term operation. Existing bridges in China, such as the Humen Bridge in Guangdong, utilize orthotropic steel decks, which have experienced fatigue cracking during operation. Various reinforcement schemes have been proposed to address these issues. Among them, the patent "A Lightweight Composite Reinforcement Structure for Fatigue-Cracked Steel Bridge Deck Requiring No Repair (Patent No.: ZL201721470446.6)" proposes a composite reinforcement structure technology that involves spot welding steel plates with short studs to the cracked bridge deck. The short studs are then welded to the deck, and finally poured with ultra-high-performance concrete. This creates a composite reinforcement structure, intended to reinforce cracked steel bridge decks.

[0003] However, this patented technology still has the following problems: 1. The steel strips are spot-welded to the cracked bridge deck and cannot be tightly combined with the cracked bridge deck. There is a gap between the two, which poses a risk of corrosion, and the steel strips are difficult to bear the force together with the cracked bridge deck; 2. The density of the steel strips is relatively high. Using too many steel strips will increase the deadweight of the bridge and reduce the safety reserve of the bridge; 3. Welding a large number of bolts on the cracked steel bridge deck will introduce welding residual stress, which poses a risk of forming new cracks and further weakens the bearing capacity of the steel bridge deck. Summary of the Invention

[0004] Unlike applying UHPC directly to intact orthotropic steel bridge decks (or repairing them to intact condition), the presence of fatigue cracks in fatigue-cracked steel bridge decks significantly reduces the steel's reinforcing effect on the UHPC. Without effective reinforcement measures on the cracked steel deck's top surface, the UHPC's underside will have extremely low tensile strength, leading to cracking. Therefore, when applying UHPC to cracked orthotropic steel bridge decks, it's crucial to fully consider the adverse effects of steel deck cracks on the stresses in the UHPC layer and implement appropriate reinforcement measures. The key is strengthening the underside of the UHPC layer to prevent cracking.

[0005] The purpose of the present invention is to provide a reinforcement structure for fatigue-cracked steel bridge decks; on the basis of the existing lightweight composite reinforcement structure, by adding carbon fiber reinforced strips and / or metal strips and improving the layout of the steel mesh, the crack resistance of the ultra-high performance concrete thin layer above the cracked steel bridge deck is enhanced; a variety of shear connector forms are used to strengthen the direct shear connection between the lightweight composite structure and the original cracked steel bridge deck; a new construction process is used to simplify the construction process and at the same time reduce damage to the cracked steel bridge deck. This structure completely eliminates the fatigue cracking disease of orthotropic steel bridge decks.

[0006] The technical solution adopted by the present invention to solve its technical problems is: it includes a cracked steel bridge deck, carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh, ultra-high performance concrete layer and wear layer, carbon fiber reinforced slats are arranged on the cracked steel deck, shear connectors are welded on the metal reinforced slats, the metal reinforced slats with shear connectors are arranged above the carbon fiber reinforced slats, the steel mesh is placed on the cracked steel bridge deck, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh and connected to the cracked steel bridge deck, and the wear layer covers the top surface of the ultra-high performance concrete layer.

[0007] The present invention also provides another reinforcement structure for fatigue cracked steel bridge decks, and its technical solution is: it includes a cracked steel bridge deck, carbon fiber reinforced strips, metal reinforced strips, shear connectors, steel mesh, ultra-high performance concrete layer and wear layer, carbon fiber reinforced strips are arranged on the cracked steel deck, shear connectors are welded on the metal reinforced strips, the metal reinforced strips with shear connectors are directly welded or glued to the cracked steel bridge deck, and are parallel to and alternately arranged with the carbon fiber reinforced strips, the steel mesh is placed on the cracked steel bridge deck, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with carbon fiber reinforced strips, metal reinforced strips, shear connectors, steel mesh and connected to the cracked steel bridge deck, and the wear layer covers the top surface of the ultra-high performance concrete layer.

[0008] The shear connector of the present invention comprises a bolt, a T-shaped steel, an L-shaped steel, a channel steel, a PBL perforated steel plate, and a bent steel bar connector.

[0009] The carbon fiber strips of the present invention are bonded to the top surface of the cracked steel bridge deck by organic structural adhesive and arranged along the transverse direction of the bridge.

[0010] The metal reinforcement strips with shear connectors of the present invention can be directly welded or glued to the cracked steel bridge deck and arranged in parallel and alternately with the carbon fiber reinforcement strips.

[0011] The steel mesh of the present invention is composed of longitudinal steel bars and transverse steel bars that are crisscrossed, and the longitudinal steel bars and transverse steel bars are evenly and equidistantly arranged between the shear connectors on the cracked steel bridge deck.

[0012] The connection method of the shear connector and the cracked steel bridge deck of the present invention includes bonding with an organic adhesive and heating fusion welding.

[0013] The carbon fiber strips of the present invention are bonded to the top surface of the cracked steel bridge deck by organic structural adhesive and arranged along the transverse direction of the bridge.

[0014] The steel mesh of the present invention includes two layers of longitudinal and transverse bridge directions, wherein the transverse bridge direction steel bars are arranged in the upper layer and the longitudinal bridge direction steel bars are arranged in the lower layer. The intersection of the longitudinal and transverse bridge direction steel bars can be tied with fine steel wires. The steel mesh is located above the carbon fiber reinforced plate and the metal reinforced plate. The diameter of the steel bar is preferably 6-16 mm, and the spacing between the steel meshes is preferably 25-100 mm.

[0015] The steel mesh of the present invention can also be three-layered. The transverse reinforcement of the three-layer steel mesh is located in the upper and lower layers of the steel mesh, and the longitudinal reinforcement is located in the middle layer of the steel mesh. The transverse reinforcement of the upper and lower layers can be on the same vertical line to increase tensile strength. The transverse reinforcement of the upper and lower layers are not on the same vertical line to facilitate the binding of the cross-section of the steel mesh.

[0016] The transverse steel bars located in the upper layer of the present invention enhance the tensile strength of the top surface of the lightweight composite structure concrete layer, and the transverse steel bars located in the lower layer enhance the tensile strength of the bottom surface of the lightweight composite structure concrete layer; the upper transverse steel bars can meet the structural requirement of excessive tensile stress in the negative bending moment area of the concrete top surface, and the lower transverse steel bars can meet the requirement of protecting the original steel bridge deck with cracks on the concrete bottom surface; if the cracks in the original steel bridge deck are not serious, only the upper transverse steel bars can be arranged; if the tensile stress in the negative bending moment area of the entire bridge is relatively small, only the lower transverse steel bars can be arranged.

[0017] The layers of the steel mesh of the present invention can be bound and fixed with fine steel wires.

[0018] The ultra-high performance concrete layer of the present invention is cast by ultra-high performance concrete, which refers to a cement-based composite material containing steel fiber, no coarse aggregate, a water-cement ratio not greater than 0.25, a compressive strength ≥100MPa, and an axial tensile strength ≥5MPa.

[0019] The ultra-high performance concrete layer of the present invention is provided with a wearing layer, and the wearing layer comprises two types: asphalt and resin.

[0020] The present invention is characterized in that it includes a cracked steel bridge deck, a shear connector, a steel mesh and an ultra-high performance concrete layer, the shear connector is fixed on the cracked steel bridge deck, the steel mesh is arranged on the cracked steel bridge deck in a criss-cross manner, and the ultra-high performance concrete layer is cast on the cracked steel bridge deck and covers the shear connector, the steel mesh and the steel bridge deck, forming a lightweight composite bridge deck reinforcement structure that solves the problem of continued cracking of the cracked steel bridge deck and eliminates the risk of continued development of cracks in the cracked steel bridge deck.

[0021] The cracks on the steel bridge deck of the present invention can be repaired according to actual conditions. It is only necessary to adjust the arrangement of the steel mesh and the form of the shear connector. It can be a three-layer steel mesh or a double-layer steel mesh, and can be studs, T-shaped steel, angle steel, L-shaped steel, or PBL (perforated steel plate connector); the shear connector is pre-fixed to the cracked steel bridge deck, and then the steel mesh is laid and tied, and the ultra-high performance concrete layer is cast in place. There is no need to adopt complex construction technology and high-investment construction equipment. The equipment investment is small, the operation is simple, and the construction is easy. The quality of the construction personnel and the construction technology requirements are relatively low.

[0022] By changing the arrangement of steel bars, including the number of steel mesh layers, the arrangement order of transverse and longitudinal steel bars, and the thickness of the steel bar protective layer, the transverse tensile stress on the bottom surface of the ultra-high performance concrete layer will not be reduced due to cracks in the steel bridge deck, thus avoiding cracking of the concrete layer and further improving the stress condition of the composite bridge deck reinforcement structure. The improved lightweight composite reinforcement structure is adopted, which significantly reduces the fatigue stress amplitude of the steel bridge deck, thereby eliminating the risk of further cracking of the steel bridge deck, and at the same time, the existing cracks will no longer continue to expand and develop.

[0023] By adopting a lightweight composite reinforcement structure to solve the problem of continued cracking of cracked steel bridge decks, the possibility of cracked steel bridge decks cracking again is basically eliminated. The cracked steel bridge deck can still continue to serve as a permanent component throughout the entire design cycle, extending its fatigue life and improving the durability of the bridge deck system.

[0024] The present invention uses both carbon fiber slats and metal slats to reinforce and strengthen cracked steel bridge decks. Compared to existing technologies, the present invention has the following advantages: 1) Carbon fiber slats have the advantages of low density and high tensile strength. Compared with pure metal slat reinforcement technology, the present invention helps reduce the weight of the bridge deck; 2) The carbon fiber slats have good bonding properties with the steel plate, tightly bonding to the cracked steel bridge deck to avoid gaps between the two, thereby improving the combined effect of the reinforcement scheme; 3) Whether the metal slats and carbon fiber slats are arranged in a stacked or parallel intermittent arrangement, they can strengthen the cracked steel bridge deck, thereby compensating for the structural defects of the cracked steel bridge deck and synergizing with the tension on the bottom surface of the ultra-high performance concrete layer to effectively prevent cracking of the bottom surface of the ultra-high performance concrete layer.

[0025] The shear keys of the present invention come in various forms, and different types can be used according to design requirements. Compared with conventional studs, shear keys such as T-shaped steel, L-shaped steel, channel steel, PBL perforated plate, and bent steel bars offer advantages such as high shear strength, high rigidity, and high efficiency, and are therefore preferred. Their use can reduce the density of shear keys, thereby minimizing on-site welding workload and effectively ensuring interlayer stress between steel and ultra-high performance concrete. Therefore, compared with existing technologies, the present invention reduces on-site welding workload, facilitating the rapid construction of old bridge reinforcement.

[0026] Cracks on the steel bridge deck of the present invention can be repaired based on practical considerations. The present invention utilizes both carbon fiber slats and metal slats with welded shear members to reinforce the cracked steel deck. Both slats overcome the structural defects caused by fatigue cracking in the steel bridge deck, significantly increasing the tensile strength of the bottom surface of the ultra-high performance concrete layer, thereby preventing cracking. Furthermore, longitudinal and transverse steel mesh is arranged on the top surface of the ultra-high performance concrete layer to increase the tensile strength of the top surface, thereby preventing cracking.

[0027] The metal strips of the present invention are welded with shear connectors, and the metal strips are connected to the cracked steel bridge deck by welding or bonding, which can ensure the effective combination of the ultra-high performance concrete layer and the steel plate, thereby greatly improving the local bending stiffness of the cracked steel bridge deck, significantly reducing the stress of the steel bridge deck caused by vehicle loads, and eliminating the risk of fatigue cracking of the steel bridge deck from the root, thereby extending the life of the steel bridge deck.

[0028] The beneficial effects of the present invention are as follows: the present invention basically eliminates the possibility of cracked steel bridge decks cracking again, and cracked steel bridge decks can still continue to serve as permanent components throughout the entire design cycle, extending their fatigue life and improving the durability of the bridge deck system. The present invention utilizes two materials, carbon fiber slats and metal slats, to reinforce cracked steel bridge decks, making full use of the advantages of the two building materials. It can not only reinforce the cracks in the steel bridge deck, but also form a combined effect with ultra-high performance concrete to effectively prevent the bottom surface of the ultra-high performance concrete layer from cracking. Therefore, the present invention has the advantages of reliable interlayer connection, good fatigue resistance, simple construction, etc., has great use value and good economic benefits, and has broad application prospects in the field of steel bridge construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention (1);

[0030] Figure 2 yes Figure 1 A side sectional view of

[0031] Figure 3 It is a structural schematic diagram of the present invention (II);

[0032] Figure 4 yes Figure 3 A side sectional view of (a);

[0033] Figure 5 yes Figure 3 Side sectional view (b).

[0034] In the figure: 1-cracked steel bridge deck, 2-carbon fiber reinforced slats, 3-metal reinforced slats, 4-shear connectors, 5-steel mesh, 6-ultra-high performance concrete layer, 7-wearing layer. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0036] Example 1, the present invention includes a cracked steel bridge deck, a carbon fiber reinforced slat, a metal reinforced slat, a shear connector, a steel mesh, an ultra-high performance concrete layer and a wear layer, wherein the carbon fiber reinforced slat is bonded to the cracked steel deck by an organic structural adhesive, the metal reinforced slat is welded with a shear connector, the metal reinforced slat with a shear connector is bonded to the top of the carbon fiber reinforced slat by an organic structural adhesive, the steel mesh is placed on the cracked steel bridge deck, the steel mesh is composed of crisscrossed longitudinal steel bars and transverse steel bars, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with the carbon fiber reinforced slat, the metal reinforced slat, the shear connector, the steel mesh and the cracked steel bridge deck, the wear layer is covered on the top surface of the ultra-high performance concrete layer, refer to Figures 1 to 5 .

[0037] Example 2: The present invention includes a cracked steel bridge deck, carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh, an ultra-high performance concrete layer, and a wear layer. Carbon fiber reinforced slats are provided on the cracked steel bridge deck, and shear connectors are welded to the metal reinforced slats. The metal reinforced slats with shear connectors are directly welded or glued to the cracked steel bridge deck and arranged parallel to and alternately with the carbon fiber reinforced slats. The steel mesh is placed on the cracked steel bridge deck. The ultra-high performance concrete layer is poured onto the cracked steel bridge deck and covered with the carbon fiber reinforced slats, metal reinforced slats, shear connectors, and steel mesh and connected to the cracked steel bridge deck. The wear layer covers the top surface of the ultra-high performance concrete layer. Figures 1 to 5 .

[0038] Example 3, the shear connector of the present invention includes a bolt, a T-shaped steel, an L-shaped steel, a channel steel, and a PBL perforated steel plate connector, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0039] Example 4, the steel bar connector of the present invention includes a bent steel bar connector, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0040] Example 5: The carbon fiber strips of the present invention are bonded to the top surface of the cracked steel bridge deck by organic structural adhesive and arranged along the transverse direction of the bridge. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0041] Example 6: The steel bars in the steel mesh of the present invention are evenly and equidistantly placed between the shear connectors on the cracked steel bridge deck. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0042] Example 7, the connection method of the shear connector of the present invention to the cracked steel bridge deck includes bonding with an organic adhesive, heating and welding, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0043] Example 8: The carbon fiber strips of the present invention are bonded to the top surface of the cracked steel bridge deck by organic structural adhesive and arranged along the transverse direction of the bridge. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0044] Example 9: The steel mesh of the present invention comprises two layers, longitudinal and transverse, wherein the transverse reinforcement is arranged in the upper layer and the longitudinal reinforcement is arranged in the lower layer. The intersection of the longitudinal and transverse reinforcements can be tied with fine steel wire. The steel mesh is located above the carbon fiber reinforced plate and the metal reinforced plate. The diameter of the steel bar is preferably 6-16 mm, and the spacing between the steel meshes is preferably 25-100 mm. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0045] Example 10: The transverse reinforcement of the three-layer steel mesh structure of the present invention is located in the upper and lower layers of the steel mesh, and the longitudinal reinforcement is located in the middle layer of the steel mesh. The transverse reinforcement of the upper and lower layers can be on the same vertical line to increase the tensile strength. The transverse reinforcement of the upper and lower layers are not on the same vertical line to increase the tensile stress in the bending moment zone. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0046] Example 11, the transverse steel bars located in the upper layer of the present invention enhance the tensile strength of the top surface of the lightweight composite concrete layer, and the transverse steel bars located in the lower layer enhance the tensile strength of the bottom surface of the lightweight composite concrete layer; the upper transverse steel bars can meet the structural requirements of excessive tensile stress in the negative bending moment area of the concrete top surface, and the lower transverse steel bars can meet the requirements of protecting the original steel bridge deck with cracks on the concrete bottom surface; if the cracks in the original steel bridge deck are not serious, only the upper transverse steel bars can be arranged; if the tensile stress in the negative bending moment area of the entire bridge is small, only the lower transverse steel bars can be arranged, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0047] Example 12: The interlayers of the steel mesh of the present invention can be tied and fixed with fine steel wires, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0048] Example 13: The ultra-high performance concrete layer of the present invention is cast by ultra-high performance concrete, wherein the ultra-high performance concrete refers to a cement-based composite material containing steel fiber, no coarse aggregate, a water-binder ratio not greater than 0.25, a compressive strength ≥ 100 MPa, and an axial tensile strength ≥ 5 MPa, see Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0049] Example 14: The ultra-high performance concrete layer of the present invention is provided with a wear-resistant layer, which includes two types of wear-resistant layers: asphalt and resin. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0050] Example 15. The present invention is characterized in that it includes a cracked steel bridge deck, a shear connector, a steel mesh and an ultra-high performance concrete layer, the shear connector is fixed on the cracked steel bridge deck, the steel mesh is crisscrossed on the cracked steel bridge deck, the ultra-high performance concrete layer is cast on the cracked steel bridge deck and covers the shear connector, the steel mesh and the steel bridge deck, forming a lightweight composite bridge deck reinforcement structure that solves the problem of continued cracking of the cracked steel bridge deck and eliminates the risk of continued development of cracks in the cracked steel bridge deck.

[0051] The cracks on the steel bridge deck of the present invention can be considered whether to repair them according to actual conditions. It is only necessary to adjust the arrangement of the steel mesh and the form of the shear connector. It can be a three-layer steel mesh or a double-layer steel mesh, and can be bolts or T-shaped steel or angle steel or L-shaped steel or PBL perforated steel plate or bent steel bar connector; the shear connector is pre-fixed on the cracked steel bridge deck, and then the steel mesh is laid and tied, and the ultra-high performance concrete layer is cast in place. There is no need to adopt complex construction technology and high-investment construction equipment. The equipment investment is small, the operation is simple, and the construction is easy. The quality of the construction personnel and the construction technology requirements are relatively low.

[0052] By changing the arrangement of steel bars, including the number of steel mesh layers, the arrangement order of transverse and longitudinal steel bars, and the thickness of the steel bar protective layer, the transverse tensile stress on the bottom surface of the ultra-high performance concrete layer will not be reduced due to cracks in the steel bridge deck, thus avoiding cracking of the concrete layer and further improving the stress condition of the composite bridge deck reinforcement structure. The improved lightweight composite reinforcement structure is adopted, which significantly reduces the fatigue stress amplitude of the steel bridge deck, thereby eliminating the risk of further cracking of the steel bridge deck, and at the same time, the existing cracks will no longer continue to expand and develop.

[0053] By adopting a lightweight composite reinforcement structure that solves the problem of continued cracking of cracked steel bridge decks, the possibility of cracking of cracked steel bridge decks again is basically eliminated. The cracked steel bridge deck can still continue to serve as a permanent component throughout the entire design cycle, extending its fatigue life and improving the durability of the bridge deck system. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0054] Example 16. The present invention uses both carbon fiber slats and metal slats to reinforce and strengthen cracked steel bridge decks. Compared with the existing technology, the present invention has the following advantages: 1) Carbon fiber slats have the advantages of low density and high tensile strength. Compared with pure metal slat reinforcement technology, the technology of the present invention helps to reduce the deadweight of the bridge deck; 2) Carbon fiber slats have good bonding performance with steel plates and can be tightly bonded to the cracked steel bridge deck to avoid gaps between the two, thereby improving the combined effect of the reinforcement scheme; 3) Regardless of whether the arrangement relationship of the metal slats and carbon fiber slats is a superimposed arrangement or a parallel intermittent arrangement, they can strengthen the cracked steel bridge deck, thereby compensating for the structural defects of the cracked steel bridge deck, coordinating the tension on the bottom surface of the ultra-high performance concrete layer, and effectively preventing the bottom surface of the ultra-high performance concrete layer from cracking, refer to Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0055] Example 17: The shear keys of the present invention come in various forms and can be used according to design requirements. Shear keys such as T-shaped steel, L-shaped steel, channel steel, PBL perforated plate, and bent steel bars offer advantages such as high shear strength, high rigidity, and high efficiency. Their use can reduce the density of shear keys, thereby minimizing on-site welding workload and effectively ensuring interlayer stress between steel and ultra-high performance concrete. Therefore, compared to existing technologies, the present invention reduces on-site welding workload, facilitating the rapid construction of old bridge reinforcement.

[0056] Cracks on the steel bridge deck of the present invention can be repaired based on practical considerations. The present invention utilizes both carbon fiber slats and metal slats with welded shear members to reinforce the cracked steel deck. Both slats overcome the structural defects caused by fatigue cracking in the steel bridge deck, significantly increasing the tensile strength of the bottom surface of the ultra-high performance concrete layer, thereby preventing cracking. Furthermore, longitudinal and transverse steel mesh is arranged on the top surface of the ultra-high performance concrete layer to increase the tensile strength of the top surface, thereby preventing cracking.

[0057] The metal strips of the present invention are welded with shear connectors, and the metal strips are connected to the cracked steel bridge deck by welding or bonding, which can ensure the effective combination of the ultra-high performance concrete layer and the steel plate, thereby greatly improving the local bending stiffness of the cracked steel bridge deck, significantly reducing the stress of the steel bridge deck caused by vehicle loads, and eliminating the risk of fatigue cracking of the steel bridge deck from the root, thereby extending the life of the steel bridge deck. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0058] Example 18: In this example, a metal strip with welded shear keys is bonded to the top surface of the carbon fiber strip. The specific implementation steps are as follows:

[0059] 1) Prepare carbon fiber slats and metal slats in the factory, weld studs to the metal slats, and then bond the metal slats with studs to the top surface of the carbon fiber slats using organic structural adhesive to form a composite slat;

[0060] 2) Bond the composite reinforcement strips to the top surface of the cracked steel bridge deck, with the reinforcement strips extending in the transverse direction of the bridge;

[0061] 3) Lay out longitudinal and transverse reinforcements in sequence. Use fine steel wire to tie the cross-sections of the reinforcement mesh.

[0062] 4) Casting the ultra-high performance concrete layer and carrying out maintenance;

[0063] Roughen the top surface of the ultra-high performance concrete layer and pour the wearing course. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

[0064] Example 19: In this example, metal strips with welded shear keys are directly bonded to the top surface of the cracked steel bridge deck, and are arranged parallel to and alternately with carbon fiber strips bonded to the top surface of the cracked steel bridge deck. The specific implementation steps are as follows:

[0065] 1) Prepare carbon fiber slats and metal slats in the factory, and weld studs to the metal slats. First, bond the carbon fiber slats to the top surface of the cracked steel bridge deck using an organic structural adhesive. Then, bond the metal slats with studs to the top surface of the cracked steel bridge deck using an organic structural adhesive, parallel to and alternating with the carbon fiber slats. Both slats extend transversely to the bridge.

[0066] 2) Lay out longitudinal and transverse reinforcements in sequence. Use fine steel wire to tie the cross-sections of the reinforcement mesh.

[0067] 3) Casting the ultra-high performance concrete layer and carrying out maintenance;

[0068] Roughen the top surface of the ultra-high performance concrete layer and pour the wearing course. Figures 1 to 5 , and the rest are the same as any one of the above embodiments or a combination of two or more embodiments.

Claims

1. A reinforcement structure for fatigue cracked steel bridge deck, characterized by: It includes a cracked steel bridge deck, carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh, ultra-high performance concrete layer and a wearing layer. Carbon fiber reinforced slats are arranged on the cracked steel deck, shear connectors are welded on the metal reinforced slats, the metal reinforced slats with shear connectors are arranged above the carbon fiber reinforced slats, the steel mesh is placed on the cracked steel bridge deck, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh and connected to the cracked steel bridge deck, and the wearing layer covers the top surface of the ultra-high performance concrete layer.

2. A reinforcement structure for fatigue cracked steel bridge decks, characterized by: It includes a cracked steel bridge deck, carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh, ultra-high performance concrete layer and a wearing layer. Carbon fiber reinforced slats are arranged on the cracked steel deck, shear connectors are welded on the metal reinforced slats, the metal reinforced slats with shear connectors are directly welded or glued to the cracked steel bridge deck, and are parallel to and alternately arranged with the carbon fiber reinforced slats, the steel mesh is placed on the cracked steel bridge deck, the ultra-high performance concrete layer is poured onto the cracked steel bridge deck, and is covered with carbon fiber reinforced slats, metal reinforced slats, shear connectors, steel mesh and connected to the cracked steel bridge deck, and the wearing layer covers the top surface of the ultra-high performance concrete layer.

3. The fatigue cracked steel bridge deck reinforcement structure according to claim 1 or 2 is characterized in that: The steel mesh is composed of longitudinal steel bars and transverse steel bars that are crisscrossed, and the longitudinal steel bars and transverse steel bars are evenly and equidistantly placed between the shear connectors on the cracked steel bridge deck.

4. The fatigue cracked steel bridge deck reinforcement structure according to claim 1 or 2 is characterized in that: The carbon fiber reinforced strips are bonded to the top surface of the cracked steel bridge deck by organic structural adhesive and arranged along the transverse direction of the bridge.

5. The fatigue cracked steel bridge deck reinforcement structure according to claim 1 or 2 is characterized in that: The steel mesh includes two layers, longitudinal and transverse bridge directions, wherein the transverse bridge direction steel bars are arranged in the upper layer and the longitudinal bridge direction steel bars are arranged in the lower layer. The intersection of the longitudinal and transverse bridge direction steel bars can be tied with fine steel wire. The steel mesh is located above the carbon fiber reinforced plate and the metal reinforced plate. The diameter of the steel bar is 6-16 mm and the spacing between the steel mesh is 25-100 mm.

6. The fatigue cracked steel bridge deck reinforcement structure according to claim 1 or 2, characterized in that: The ultra-high performance concrete layer is cast by ultra-high performance concrete, which refers to a cement-based composite material containing steel fiber, no coarse aggregate, a water-cement ratio not exceeding 0.25, a compressive strength ≥100 MPa, and an axial tensile strength ≥5 MPa.

7. The reinforcement structure for fatigue cracked steel bridge deck according to claim 1 or 2, characterized in that: A wearing layer is provided on the ultra-high performance concrete layer, and the wearing layer comprises two types: asphalt and resin.

8. The fatigue cracked steel bridge deck reinforcement structure according to claim 1 or 2, characterized in that: The shear connectors include studs, T-shaped steel, L-shaped steel, channel steel, PBL perforated steel plates, and bent steel bar connectors.

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