Prefabricated steel reinforced concrete beam reinforced by UHPC (Ultra High Performance Concrete)

Abstract

The utility model belongs to the technical field of constructional engineering, and particularly relates to a prefabricated steel reinforced concrete beam reinforced by UHPC (Ultra High Performance Concrete). The concrete beam comprises a beam body, the beam body comprises body concrete, profile steel and a reinforcement cage, the profile steel and the reinforcement cage are solidified in the body concrete, the concrete beam further comprises a UHPC restoration body arranged in a concrete emptying notch in the damaged position of the beam body, and a restoration welding seam is arranged at the fracture position, corresponding to the UHPC restoration body, of the profile steel. Repairing steel bars are fixed to the fracture, corresponding to the UHPC repairing body, of the steel reinforcement cage. The fractures of the reinforcement cage and the section steel are reinforced or repaired, and the UHPC repairing body is arranged at the damaged part of the beam body, so that the structural performance of the concrete beam is recovered under the combined action of the UHPC repairing body, the reinforcement cage and the section steel, and the service life of the concrete beam is further prolonged; in the operation process, construction processes such as punching and steel bar planting do not need to be carried out in an original concrete beam structure, structural damage to the original concrete beam is avoided, and the construction process is simplified.

Description

Technical Field

[0001] The utility model belongs to the technical field of building engineering, and specifically relates to a prefabricated assembled steel concrete beam reinforced by UHPC. Background Art

[0002] Prefabricated Steel Reinforced Concrete (PSRC) structure is a concrete structure that combines a prefabricated concrete structure with a steel concrete structure. Compared with the traditional cast-in-place method, the prefabricated concrete structure has the advantages of high production efficiency, fast construction speed, good construction quality, low consumption, and environmental protection. Figure 1 As shown, it is a common PSRC structure, which generally includes a steel cage formed by a plurality of lower longitudinal bars 2, upper longitudinal bars 5 and a plurality of closed stirrups 4. A steel section 3 is arranged in the accommodation space formed by the steel cage. The steel section 3 and a part of the steel cage are buried in the precast concrete 1 in a U-shaped groove.

[0003] When PSRC structures are used in high-speed railway station track layers and heavy-load railway bridges, they are mainly subjected to high-cycle fatigue loads. PSRC structures are prone to fatigue failure after bearing a large amount of fatigue loads, which causes fractures in the longitudinal reinforcement and steel sections of PSRC beams, resulting in a shallow "V" shape in the overall morphology of fatigue-damaged PSRC beams. The concrete in the mid-span tension zone cracks and the cracks are fully developed, and the concrete in the mid-span compression zone is crushed; at this time, the lower flange of the steel section in the PSRC beam is completely cracked and extends upward to the web, and the lower longitudinal reinforcements are fatigue-fractured and have at least one fracture. In order to restore the bearing capacity of the PSRC beam as soon as possible and continue to use it, it is necessary to reinforce the fatigue-damaged parts of the PSRC structure. Ultra-high performance concrete (UHPC) is a new type of cement-based composite material based on the principle of maximum packing density. It has the characteristics of ultra-high mechanical properties, toughness, durability and good construction performance. Using UHPC to reinforce PSRC structures is a better choice among the commonly used reinforcement methods. For example, a Chinese invention patent application with application publication number CN110630030A discloses a P-UHPC reinforcement device for reinforced concrete structures, including a UHPC reinforcement layer and connecting steel bars fixed to the bottom of the reinforced concrete structure, one end of the connecting steel bar is fixed in the concrete structure, and the other end is fixed in the UHPC reinforcement layer.

[0004] After analysis, it was found that the above-mentioned reinforcement structure is only applicable to the situation where the bearing surface of the original concrete structure has not been broken and there is no fracture in the steel cage. At the same time, when using this reinforcement structure, it is necessary to perform construction processes such as drilling and planting steel bars in the original concrete structure, which will cause greater damage to the original structure. At the same time, the concrete cross-section of the reinforced section is larger than that of the original concrete structure, which also leads to a certain loss of clearance. Utility Model Content

[0005] The purpose of the utility model is to provide a prefabricated assembled steel concrete beam reinforced with UHPC to solve the problem that the existing concrete reinforcement structure is not suitable for the concrete beam bearing surface to be broken and the steel cage has a fracture, and at the same time solve the problem that the construction processes such as drilling and planting steel bars during reinforcement are easy to cause damage to the original concrete structure, and the problem that the concrete cross-section after reinforcement is increased and a certain amount of clearance is lost.

[0006] In order to achieve the above purpose, the prefabricated steel concrete beam reinforced with UHPC in the utility model adopts the following technical solutions:

[0007] A prefabricated steel-concrete beam reinforced with UHPC, the concrete beam comprising a beam body, the beam body comprising body concrete and steel and a steel cage cured in the body concrete, the concrete beam further comprising a UHPC repair body arranged in a concrete hollowing gap at a damaged portion of the beam body, a repair weld being arranged at a fracture of the steel corresponding to a position of the UHPC repair body, and a repair steel bar being fixed at a fracture of the steel cage corresponding to a position of the UHPC repair body.

[0008] The beneficial effect of the above technical solution is that: the utility model is based on the improvement of the prior art, by welding and repairing the fracture of the steel section corresponding to the position of the UHPC repair body, fixing and repairing the steel bars at the fracture of the steel cage corresponding to the position of the UHPC repair body, and setting the UHPC repair body in the concrete clearance gap at the damaged part of the beam body of the concrete beam to reinforce and repair the damaged part of the beam body. The utility model reinforces or repairs the fracture of the steel cage and the steel section, and sets the UHPC repair body at the damaged part of the beam body. Under the combined effect of the UHPC repair body, the steel cage and the steel section, as well as the excellent crack control ability and ultra-high durability of UHPC, the durability of the UHPC repair body at the damaged part can be greatly improved, thereby extending the service life of the steel section and the steel cage, and restoring the existing structural performance of the concrete beam, thereby improving the service life of the concrete beam. At the same time, during the reinforcement and repair operation, there is no need to perform construction techniques such as drilling and planting steel bars in the original concrete beam structure, which will not cause structural damage to the original concrete beam, simplifying the construction process and making the construction simple. UHPC has the advantages of light weight and good durability, and will not cause overload to the original concrete structure.

[0009] Furthermore, two ends of the repair steel bar are overlapped and fixed at the fracture of the steel cage.

[0010] The beneficial effect of the above technical solution is that: such an arrangement completes the reinforcement of the fracture of the steel cage by overlapping the repair steel bars at the fracture of the steel cage.

[0011] Furthermore, the diameter of the steel bar at the fracture of the steel cage is d, and the lap lengths at both ends of the repair steel bar are 7d to 13d respectively.

[0012] The beneficial effect of the above technical solution is that such a setting effectively reduces the overlap length at both ends of the repair steel bars, and meets the connection strength requirement by minimizing the overlap section length.

[0013] Furthermore, the repair steel bars are overlapped and fixed on the inner side of the steel cage and close to the steel section.

[0014] The beneficial effect of the above technical solution is that such a setting can effectively ensure the pouring thickness of the UHPC at the repair steel bar cage, thereby improving the structural strength of the UHPC repair body, and further ensuring the UHPC reinforcement effect.

[0015] Furthermore, the diameter of the repaired steel bar is equal to the diameter of the steel bar at the fracture of the steel cage.

[0016] The beneficial effect of the above technical solution is that such a setting ensures that the repair steel bars and the steel bars at the fracture of the steel cage have the same connection strength, which can effectively improve the service life of the two after the UHPC is poured.

[0017] Furthermore, the interface between the beam body and the UHPC restoration is a non-planar structure with a stepped shape or a concave-convex variation.

[0018] The beneficial effect of the above technical solution is that such a setting can enhance the bonding force between the beam body and the UHPC restoration at the concrete interface, thereby preventing the beam body and the UHPC restoration from failing due to adhesion and detachment.

[0019] Furthermore, the cross-sectional dimensions of the UHPC restoration are the same as the cross-sectional dimensions of the beam body.

[0020] The beneficial effect of the above technical solution is that such a setting is convenient for construction, and after the construction is completed, the deadweight of the original prefabricated assembled steel concrete structural beam is less affected, and the clearance of the concrete beam will not be reduced.

[0021] Furthermore, the steel section is an H-shaped steel section, which includes an upper flange, a lower flange, and a web connected between the upper flange and the lower flange, and the repair weld is located on the web and the lower flange.

[0022] The beneficial effect of the above technical solution is that with such a configuration, the H-shaped steel has higher structural stability and structural strength, and the repair welds located on the web and the lower flange can restore the structural stability and structural strength of the steel after repair, thereby enhancing the service life of the prefabricated assembled steel concrete beam with damaged parts after pouring UHPC.

[0023] Furthermore, the repair weld extends from the lower flange to the intersection of the web and the upper flange.

[0024] The beneficial effect of the above technical solution is that the repair weld extends from the lower flange to the junction of the web and the upper flange, which is convenient for ensuring that the steel section remains straight and free of warping after welding repair, and can basically be restored to the shape before fatigue damage, thereby effectively ensuring that the steel section restores structural stability and structural strength.

[0025] Furthermore, the steel cage includes at least four longitudinal steel bars arranged in a polygonal shape and a plurality of stirrups fixed outside each longitudinal steel bar and arranged at intervals, and the fracture of the steel cage is located on the longitudinal steel bars.

[0026] The beneficial effects of the above technical solution are: with such a setting, the structure of the steel cage is simple and easy to process, and the concrete beam formed after solidification into concrete has good compressive, shear and tensile properties; when the fracture is formed on the longitudinal steel bars, it is easy to reinforce the steel cage, and after the fracture is reinforced, it is easy to restore its tensile and shear properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the prefabricated steel concrete beam in the utility model;

[0028] Figure 2 This is a schematic diagram of the structure of the prefabricated steel concrete beam reinforced with UHPC in the utility model;

[0029] Figure 3 for Figure 2 Sectional view at AA;

[0030] Figure 4 for Figure 2 Cross-sectional view at BB in the middle.

[0031] In the figure: 1. Precast concrete; 2. Lower longitudinal reinforcement; 3. Steel section; 4. Stirrups; 5. Upper longitudinal reinforcement; 6. Repair steel bars; 7. Longitudinal reinforcement fracture; 8. Repair weld; 9. Ultra-high performance concrete; 10. Concrete interface; 11. Overlay surface; 12. Cast-in-place concrete; 31. Upper flange; 32. Web; 33. Lower flange; 100. UHPC repair body. DETAILED DESCRIPTION

[0032] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0033] Embodiment 1 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0034] The reinforcement structure of the existing concrete structure is only applicable to the situation where the bearing surface of the original concrete structure is not broken and there is no fracture in the steel cage. At the same time, the reinforcement structure needs to perform construction processes such as drilling and planting steel bars in the original concrete structure when applied, which will cause greater damage to the original structure. At the same time, the concrete cross-section of the reinforced section is larger than that of the original concrete structure, which also leads to a certain loss of clearance.

[0035] In order to solve the above problems, the utility model provides a prefabricated assembled steel-concrete beam reinforced with UHPC, the concrete beam comprising a beam body, the beam body comprising body concrete and steel and a steel cage solidified in the body concrete, the concrete beam also comprising a UHPC repair body arranged in a concrete hollowing gap at a damaged part of the beam body, a repair weld is arranged at the fracture of the steel corresponding to the position of the UHPC repair body, and a repair steel bar is fixed at the fracture of the steel cage corresponding to the position of the UHPC repair body.

[0036] The utility model is an improvement based on the prior art. The fracture of the steel section corresponding to the position of the UHPC repair body is welded and repaired, the steel bar is fixed and repaired at the fracture of the steel cage corresponding to the position of the UHPC repair body, and the UHPC repair body is set in the concrete clearance gap at the damaged part of the concrete beam to reinforce and repair the damaged part of the beam body. The utility model reinforces or repairs the fracture of the steel cage and the steel section, and sets the UHPC repair body at the damaged part of the beam body. Under the comprehensive effect of the UHPC repair body, the steel cage and the steel section, and the excellent crack control ability and ultra-high durability of UHPC, the durability of the UHPC repair body at the damaged part can be greatly improved, thereby extending the service life of the steel section and the steel cage, and restoring the existing structural performance of the concrete beam, thereby improving the service life of the concrete beam. At the same time, during the reinforcement and repair operation, it is not necessary to perform construction processes such as drilling and planting steel bars in the original concrete beam structure, so that the original concrete beam will not be damaged in structure, the construction process is simplified, and the construction is simple; UHPC has the advantages of light weight and good durability, and will not cause overload to the original concrete structure.

[0037] like Figures 1 to 4 As shown, the prefabricated assembled steel concrete beam comprises a beam body and a UHPC repair body 100 disposed in a concrete hollowing notch at a location where the beam body is damaged.

[0038] The beam body includes body concrete and steel 3 and a steel cage solidified in the body concrete. The body concrete includes precast concrete 1 and cast-in-place concrete 12. The steel cage is formed by a plurality of lower longitudinal bars 2 arranged in a polygonal shape, upper longitudinal bars 5 parallel to the lower longitudinal bars 2, and a plurality of closed stirrups 4 fixed to the lower longitudinal bars 2 and arranged outside the lower longitudinal bars 2 at intervals. The steel 3 is arranged in the accommodation space formed by the steel cage. The steel 3 includes an upper flange 31, a lower flange 33, and a web 32 connected between the upper flange 31 and the lower flange 33. The precast concrete 1 is in a U-shaped groove shape, and a portion of the steel 3 and the steel cage is solidified in the precast concrete 1. The precast concrete 1 is connected to the cast-in-place concrete 12, and the other portion of the steel cage and the steel 3 is solidified in the cast-in-place concrete 12.

[0039] In this embodiment, the lower flange 33 and a part of the web 32 of the steel section 3 are solidified in the groove bottom of the precast concrete 1 and are parallel to the groove length direction of the precast concrete 1. The top of the steel section 3 is located below the top of the stirrup 4, and the lower part of the stirrup 4 is located in the groove wall and groove bottom of the precast concrete 1. The lower longitudinal reinforcement 2 is welded to the bottom of the stirrup 4, and the upper longitudinal reinforcement 5 parallel to the lower longitudinal reinforcement 2 is welded to the top of the stirrup 4. The precast concrete 1, stirrup 4, lower longitudinal reinforcement 2, upper longitudinal reinforcement 5 and the steel section 3 are all precast parts of the precast assembled steel concrete beam; after the concrete is poured on site, the upper flange 31 and another part of the web 32 of the steel section 3, the upper part of the stirrup 4 and the upper longitudinal reinforcement 5 are all located in the cast-in-place part of the precast assembled steel concrete beam; after the casting is completed, the overlap surface 11 is formed between the precast concrete 1 and the cast-in-place concrete 12.

[0040] In this embodiment, the steel section 3 is an H-shaped steel, an I-shaped steel or a honeycomb steel; the lower longitudinal reinforcement 2, the upper longitudinal reinforcement 5 and the stirrups 4 are all high-strength steel bars.

[0041] A repair weld 8 is provided at the fracture of the steel section 3 corresponding to the position of the UHPC repair body 100. Specifically, the fatigue-damaged steel section 3 cracks from the lower flange 33 and extends to the web 32. The repair weld 8 extends from the lower flange 33 of the steel section to the junction of the web 32 and the upper flange 31 to restore the structural performance of the steel section 3.

[0042] A repair steel bar 6 is provided at the fracture of the steel cage corresponding to the position of the UHPC repair body 100. Specifically, a longitudinal reinforcement fracture 7 occurs at the lower longitudinal reinforcement 2 damaged by fatigue, and the two ends of the repair steel bar 6 are overlapped and fixed at the longitudinal reinforcement fracture 7 of the lower longitudinal reinforcement 2. In this embodiment, the two ends of the repair steel bar 6 are connected to the lower longitudinal reinforcement 2 by binding and overlapping.

[0043] In order to ensure the reinforcement effect, the length of the UHPC repair body 100 needs to be greater than the lap distance between the repair steel bar 6 and the lower longitudinal bar 2. Specifically, the repair steel bar 6 uses a steel bar with the same diameter as the lower longitudinal bar 2, and the lap lengths between the two ends of the repair steel bar 6 and the lower longitudinal bar 2 are 10d respectively. The lap distance is the sum of the lap lengths between the two ends of the repair steel bar 6 and the lower longitudinal bar 2 and the fracture length of the lower longitudinal bar 2, that is, the sum of 20d and the fracture length of the lower longitudinal bar 2, where d is the diameter of the lower longitudinal bar; in this way, the overlapping parts of the repair steel bar 6 and the lower longitudinal bar 2 are all located in the UHPC repair body 100, and UHPC can greatly improve the bonding strength between it and the steel bars of the steel cage, which can ensure the structural strength of the reinforced steel concrete beam and effectively reduce the lap length of the repair steel bar 6.

[0044] In this embodiment, in order to ensure the pouring thickness of the UHPC of the lower longitudinal reinforcement 2, the repair steel bar 6 is arranged on the inner side of the stirrup 4 and close to the lower flange 33 of the steel section 3. Specifically, the repair steel bar 6 is arranged on the inner side of the stirrup 4 and close to the lower flange 33 of the steel section 3 along the height direction of the stirrup 4. In this way, the structural strength of the UHPC repair body 100 can be effectively improved, thereby ensuring the effect of UHPC reinforcement.

[0045] The UHPC restoration 100 is disposed in the concrete hollowing gap at the damaged portion of the beam body. Specifically, ultra-high performance concrete 9 is poured in the concrete hollowing gap to form the UHPC restoration 100 and form a concrete interface 10 between the UHPC restoration 100 and the main concrete of the beam body.

[0046] In this embodiment, the concrete interface 10 is a non-planar structure with stepped or concave-convex changes. In this way, after pouring the ultra-high performance concrete 9, the bonding force between the beam body and the UHPC restoration 100 at the concrete interface 10 can be enhanced to prevent the beam body and the UHPC restoration 100 from failing due to adhesion and detachment.

[0047] In this embodiment, the cross-sectional dimensions of the cast UHPC restoration 100 are consistent with the cross-sectional dimensions of the prefabricated assembled steel concrete beam. Specifically, the cross-sectional dimensions of the UHPC restoration 100 are consistent with the cross-sectional dimensions of the beam body, so that the self-weight of the prefabricated assembled steel concrete beam is less affected.

[0048] After the concrete gap is cleared and the ultra-high performance concrete 9 is poured, the repair steel bar 6, part of the steel 3, and part of the steel cage are all wrapped by the ultra-high performance concrete 9. Specifically, the repair weld 8 formed by welding is located inside the UHPC repair body 100, and the repair steel bar 6 and the longitudinal reinforcement fracture 7 are both located inside the UHPC repair body 100. In this way, since ultra-high performance concrete has the advantages of light weight and good durability, it will not cause overload to the original prefabricated steel concrete structure; at the same time, the excellent compression and tensile properties of ultra-high performance concrete can be fully utilized to enhance the connection strength of the UHPC repair body; the new type of reinforcement structure is simple, and there is no need to construct the original prefabricated steel concrete structure, the construction is also simple, and the reinforcement effect is good.

[0049] It should be noted that UHPC does not contain coarse aggregate, has excellent flowability and vibration-free characteristics, and can ensure the density of concrete pouring; UHPC's dense matrix can improve the interfacial bonding strength between steel sections, steel bars and UHPC, and can reduce the thickness of the steel section's protective layer, thereby increasing the distance between the steel section's flange and the neutral axis of the cross section, which is beneficial to the full play of the steel section's tensile strength; in addition, since the steel cage and steel sections are built into the UHPC during reinforcement, UHPC's excellent crack control ability and ultra-high durability can greatly improve the durability of the UHPC repair body at the damaged site, extend the service life of the steel cage and steel sections, and reduce the later maintenance costs of the steel cage and steel sections.

[0050] Based on the structure of the prefabricated steel concrete beam reinforced with UHPC, the specific processing and construction includes the following steps:

[0051] S1: Removal of damaged concrete. After fatigue failure, the concrete in the mid-span of the PSRC beam is damaged. The slope-damaged area is excavated to remove the concrete that is detached from the surface of the steel 3 in the mid-span. In order to avoid affecting the bearing capacity of the repaired PSRC beam, the area where the precast concrete 1 and the cast-in-place concrete 12 are completely bonded to the H-shaped steel 3 must be processed. After the damaged concrete in this area is removed, a concrete clearance gap is formed on the PSRC beam.

[0052] During the excavation, the end surface of the PSRC beam opposite to the concrete notch is roughened. In this embodiment, the concrete interface 10 between the cast-in-place concrete 12 and the precast concrete 1 and the UHPC restoration 100 is made to have a non-planar structure with steps or concave-convex changes, so as to enhance the bonding force between the main concrete and the UHPC restoration 100 at the concrete interface 10.

[0053] S2: Deformation correction of PSRC beam. First, use a spray gun to remove the uneven instantaneous break area at the fracture of H-beam 3 and the unbroken part of web 32, so that a flat crack is formed between the lower flange 33 of H-beam 3 and web 32, and the crack is opened to the upper flange 31 of H-beam 3 to remove the plastic deformation area at the fracture section of H-beam 3, so as to facilitate the correction of deformation; then, turn the PSRC beam over to make it opposite to the original fatigue loading direction, and slowly close the crack of steel 3 through fatigue testing machine and distribution beam. After correction, ensure that the lower flange 33 and web 32 of the broken H-beam 3 can be straightly connected without distortion, overlapping and warping, and the surface of flange and web 32 is flat.

[0054] It should be noted that during the correction process, the load applied by the fatigue testing machine should be determined by the deformation recovery of the PSRC beam. During the correction process, the deformation of the PSRC beam should be closely observed to avoid over-correction or under-correction. Safety ropes are tied at both ends of the PSRC beam to prevent the PSRC beam from sliding during correction. After the load is removed, the PSRC beam remains basically straight to meet the correction requirements. Otherwise, the correction operation should be repeated until the requirements are met. After the deformation correction is completed, the PSRC beam is fixed to ensure the safety of subsequent processing.

[0055] S3: Welding repair of cracked steel. The treated H-beam 3 fracture is welded with a butt weld to weld the lower flange 33 and web 32 of the cracked H-beam 3. The welding starting point of the repair weld 8 of the steel 3 is the intersection of the upper flange 31 and web 32 of the H-beam 3, and it is welded from the web 32 to the lower flange 33 of the H-beam 3. The strength of the welding rod should match the strength of the parent material. After the deformation correction and the welding of the cracked H-beam 3 are completed, the PSRC beam should remain basically straight without warping, and basically return to the shape before fatigue damage.

[0056] S4: Repair of broken longitudinal reinforcement. The lower longitudinal reinforcement 2 of the PSRC beam is fatigue fractured under fatigue load. There is at least one longitudinal reinforcement fracture 7 in the lower longitudinal reinforcement 2. The two ends of the repair steel bar 6 are overlapped and fixed at the longitudinal reinforcement fracture 7. In this embodiment, the repair steel bar 6 uses steel bars with the same diameter as the lower longitudinal reinforcement 2. The two ends of the repair steel bar 6 are connected to the lower longitudinal reinforcement 2 by binding and overlapping. The overlap lengths of the two ends of the repair steel bar 6 and the longitudinal reinforcement fracture 7 of the lower longitudinal reinforcement 2 are 10d, that is, the length of the repair steel bar 6 is at least 20d and the sum of the fracture length. In order to ensure the thickness of the protective layer of the lower longitudinal reinforcement 2, the repair steel bar 6 is arranged on the inner side of the stirrup 4 and close to the lower flange of the H-shaped steel 3.

[0057] S5: Casting of UHPC. The excavated surface in the concrete hollowing gap is moistened, and the concrete of the PSRC beam is cast with ultra-high performance concrete 9 (UHPC) after steel formwork is used to cast the missing concrete in the hollowing gap to form a UHPC repair body 100. After curing at room temperature, the actual size of the repaired PSRC beam is measured.

[0058] Embodiment 2 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0059] In Example 1, the fracture of the steel cage is located on the longitudinal steel bars. In this embodiment, the fracture of the steel cage is located on the stirrups.

[0060] Embodiment 3 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0061] In Example 1, the repair weld extends from the lower flange to the intersection of the web and the upper flange. In this embodiment, the repair weld is only located on the lower flange; in other embodiments, the repair weld extends from the lower flange to the middle of the web.

[0062] Embodiment 4 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0063] In Example 1, the cross-sectional size of the UHPC restoration is the same as the cross-sectional size of the beam body. In this embodiment, the cross-sectional size of the UHPC restoration is smaller than or larger than the cross-sectional size of the beam body; in other embodiments, the cross-sectional size of the connection between the UHPC restoration and the beam body is the same as the beam body, while the cross-sectional size of the middle part of the UHPC is smaller than or larger than the cross-sectional size of the beam body.

[0064] Embodiment 5 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0065] In Example 1, the interface between the beam body and the UHPC restoration is a stepped or non-planar structure with concave and convex changes. In this embodiment, the interface between the beam body and the UHPC restoration is a planar structure or a regular curved surface structure, wherein the curved surface structure can be a roughened curved surface or a smooth curved surface.

[0066] Embodiment 6 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0067] In Example 1, the diameter of the repaired steel bar is equal to the diameter of the steel bar at the fracture of the steel cage. In this embodiment, the diameter of the repaired steel bar is larger or smaller than the diameter of the steel bar at the fracture of the steel cage.

[0068] Embodiment 7 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0069] In Example 1, the repair steel bar is overlapped and fixed on the inner side of the steel cage and close to the steel section. In this embodiment, the repair steel bar is overlapped and fixed on the outer side of the steel cage and away from the steel section; in other embodiments, the repair steel bar is overlapped and fixed on the inner side of the steel cage, specifically on the inner side along the width direction of the stirrup.

[0070] Embodiment 8 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0071] In Example 1, the overlap lengths of the two ends of the repaired steel bars are 10 d. In this embodiment, the overlap lengths of the two ends of the repaired steel bars are 5 d, 7 d, 9 d, 11 d or other suitable lengths to ensure that the structural performance of the UHPC repair body meets the requirements.

[0072] Embodiment 9 of the prefabricated steel concrete beam reinforced with UHPC in the present invention:

[0073] In Example 1, the two ends of the repaired steel bar are overlapped and fixed at the fracture of the lower longitudinal bar. In this embodiment, the two ends of the repaired steel bar are welded flush with the fracture of the lower longitudinal bar.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the description and drawings of the present invention shall be included in the protection scope of the present invention.

Claims

1. A prefabricated steel-concrete beam reinforced with UHPC, the concrete beam comprising a beam body, the beam body comprising body concrete and profiled steel and a reinforcement cage cured in the body concrete, characterized in that: The concrete beam also includes a UHPC repair body arranged in the concrete hollowing gap at the damaged part of the beam body, a repair weld is arranged at the fracture of the steel section corresponding to the position of the UHPC repair body, and a repair steel bar is fixed at the fracture of the steel cage corresponding to the position of the UHPC repair body, the length of the repair steel bar is greater than the length of the fracture, and the repair steel bar is arranged on the inner side of the stirrup of the steel cage and close to the position of the steel section.

2. The prefabricated steel concrete beam reinforced with UHPC according to claim 1, characterized in that: The two ends of the repair steel bar are overlapped and fixed at the fracture of the steel cage.

3. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The diameter of the steel bar at the fracture of the steel cage is d, and the lap lengths at both ends of the repair steel bar are 7d~13d respectively.

4. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The repair steel bar is arranged on the inner side of the stirrup and along the height direction of the stirrup.

5. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The interface between the beam body and the UHPC restoration is a non-planar structure with stepped or concave-convex changes.

6. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The cross-sectional dimensions of the UHPC restoration are the same as those of the beam body.

7. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The steel section is an H-shaped steel section, which includes an upper flange, a lower flange, and a web connected between the upper flange and the lower flange, and the repair weld is located on the web and the lower flange.

8. The prefabricated steel concrete beam reinforced with UHPC according to claim 7, characterized in that: The repair weld extends from the lower flange to the intersection of the web and the upper flange.

9. The prefabricated steel concrete beam reinforced with UHPC according to claim 1 or 2, characterized in that: The steel cage comprises at least four longitudinal steel bars arranged in a polygonal shape and a plurality of stirrups fixed outside each longitudinal steel bar and arranged at intervals. The fracture of the steel cage is located on the longitudinal steel bars.

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