Design method for transverse unbonded prestressed steel bar anchorage device structure of bridge deck slab

Abstract

The invention provides a method for designing a transverse unbonded prestressed steel bar anchorage device structure of a bridge deck slab, and relates to the technical field of bridge steel bar construction. The design method of the transverse unbonded prestressed steel bar anchorage device structure for the bridge deck slab comprises the following steps that S1, the unbonded prestressed steel bar anchorage device structure suitable for the transverse prestressed steel bar distribution requirement of the bridge deck slab is designed and completed by combining the steel bar distribution space of the bridge deck slab and referring to the size parameters of transverse prestressed flat anchors. According to the method, the occupied space of rib arrangement is small, the requirement for rib arrangement of narrow sections of bridge decks and the like is met, an unbonded structure is adopted, construction is easy, pipeline reservation and later grouting are not needed, the risk that prestressed ribs are corroded and fractured in a high-stress state due to the fact that pipeline grouting is not solid, hole channel slurry leakage or slurry separation is eradicated, and the service life of the prestressed ribs is prolonged. The unbonded prestressed steel bar is anchored in a supporting type threaded mode, the anchoring precision is high, and the tensioning control requirement can be met through one-time precise tensioning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge steel bar construction, in particular to a bridge deck slab transverse unbonded prestressed steel bar anchorage structure design method. BACKGROUND

[0002] Prestressed concrete continuous box girder bridge has the advantages of good overall performance, large structural stiffness, small deformation and good seismic performance. In addition, the design and construction of prestressed continuous girder bridge are relatively mature, the construction quality and construction period can be controlled, and the maintenance workload after the bridge is completed is small, so this type of bridge is widely used in highway and railway bridge engineering.

[0003] In traditional design, the bridge deck slab transverse prestressed system mostly uses bonded and unbonded prestressed steel bar flat anchors. Through investigation, it is found that the transverse prestress is difficult to grout horizontally, and the prestressed pipe grouting is not real, which cannot meet the design requirements, resulting in corrosion of prestressed tendons in high stress state, causing certain safety hazards.

[0004] At present, the transverse bending moment of the top and bottom plate of the box girder and continuous girder is too large, which causes cracks in the top and bottom plate of the bridge. Other cracks include longitudinal cracks at the web of the top and bottom plate of the box girder, oblique cracks and horizontal cracks on the web, etc. The causes of these cracks are various, but they are all related to transverse prestress. The appearance of cracks will affect the integrity and carrying capacity of the structure and reduce the service life of the bridge.

[0005] The existing bridge transverse prestress mainly uses steel strand clip anchor, and the construction adopts bonded method. The defects of the prior art are: low extension rate of steel strand clip anchor, poor seismic energy absorption, large stress loss of retraction anchoring method, and large construction stress deviation. The construction adopts bonded method, the hole grouting has disadvantages, the grouting is not real, and the shrinkage of concrete after grouting produces gaps, which will cause corrosion of steel bars. When the steel bars rust, the effective cross-sectional area decreases, the structural carrying capacity decreases, and then cracks and deformation problems may occur. At the same time, steel bar corrosion will accelerate the aging and destruction process of the structure and shorten the service life of the bridge.

[0006] Therefore, the bridge deck slab transverse unbonded prestressed steel bar anchorage structure design method is provided by the person skilled in the art to solve the problems in the background art. SUMMARY

[0007] (I) Technical problems solved In view of the deficiencies of the prior art, the bridge deck transverse unbonded prestressed steel rod anchor structure design method is provided, based on the deficiencies of the unbonded prestressed steel rod anchor nut anchor and the finished rolled threaded steel anchor, the unbonded prestressed steel rod anchor structure is designed, the problems of large prestress loss in short distance and unreal grouting of embedded pipes with adhesive are solved, the bridge deck cracking problem is solved, and the service life of the bridge is prolonged.

[0008] (II) Technical scheme To achieve the above object, the following technical scheme is adopted: The bridge deck transverse unbonded prestressed steel rod anchor structure design method comprises the following processes: Step S1. In combination with the bridge deck reinforcement space, referring to the transverse prestressed flat anchor size parameters, the unbonded prestressed steel rod anchor structure suitable for the bridge deck transverse prestressed reinforcement requirement is designed; Step S2. The unbonded prestressed steel rod anchoring structure of multiple groups is respectively calculated for the concrete crack resistance and local bearing strength under the anchor; Step S3. The anchoring assembly and spherical angle design selection are performed; Step S4. Through analysis of the design drawings, the bridge longitudinal prestressed pipe and its position, the transverse prestressed pipe and its position, and the arrangement position of the top plate longitudinal and transverse ordinary steel reinforcement are analyzed; Step S5. The static load anchoring performance test of the new unbonded prestressed steel rod anchor assembly is performed, including: static load anchoring efficiency, ultimate total strain and ultimate failure form; Step S6. Curve reinforcement feasibility and single-end tension test ① Curve reinforcement feasibility: two forms of curve reinforcement and multiple curve reinforcement in the bridge transverse prestress are selected, the representative reinforcement curvature in the design drawings is simulated and verified to determine the curve reinforcement feasibility of the prestressed steel rod; ② Prestressed tension test: a concrete proportional model is made according to the reinforcement form of the previous curve reinforcement simulation test, two reinforcement forms of reinforcement curvature radius R400x4 bends and curvature radius R600x2 bends are taken, and each prestressed steel rod in different states is numbered and marked, the vibrating string anchor cable meter is calibrated before the test to meet the accuracy requirement, ensure the accuracy and effectiveness of the experimental data, and the tensioning force is preferably set to 190kN; Step S7. Unbonded prestressed steel rod concrete model without fracture and crack out test; Step S8. Safety test of unbonded prestressed steel rod protection device, open prestressed steel rod tensioning and breaking out test without concrete wrapping.

[0009] Further, in the step S2, for the anchoring assembly of 2 in a group, the crack resistance and local bearing strength of the concrete under the anchor are calculated as follows: 1) The crack resistance calculation of the concrete under the anchor refers to JTG 3362-2018 "Highway Reinforced Concrete and Prestressed Concrete Bridge Design Specification" 5.7.1 The crack resistance of the concrete under the anchor of φ16-2 steel bar is calculated, 2) The local bearing strength calculation of the concrete under the anchor refers to JTG 3362-2018 "Highway Reinforced Concrete and Prestressed Concrete Bridge Design Specification" 5.7.2 Requirements.

[0010] Further, in the step S2, for the anchoring assembly of 3 in a group, the crack resistance and local bearing strength of the concrete under the anchor are calculated as follows: 1) The crack resistance calculation of the concrete under the anchor refers to JTG 3362-2018 "Highway Reinforced Concrete and Prestressed Concrete Bridge Design Specification" 5.7.1 The crack resistance of the concrete under the anchor of φ16-3 steel bar is calculated, 2) The local bearing strength calculation of the concrete under the anchor refers to JTG 3362-2018 "Highway Reinforced Concrete and Prestressed Concrete Bridge Design Specification" 5.7.2 Requirements.

[0011] Further, in the step S3, in order to achieve the best effect of the spherical angle design of the anchoring assembly, the research and development group members in the design process determine the best design angle by means of finite element analysis combined with actual test verification, and consider the safety redundancy: when the finite element analysis is carried out, the limit breaking force of the un-bonded prestressed steel bar is selected for analysis, and there is no abnormality.

[0012] Further, in the step S6, the test process of the prestressed tension test includes: ①. Steel bar binding and prestressed steel bar layout; ②. Concrete model pouring; ③. Measurement sensor calibration; ④. Simulation of tension test.

[0013] Further, in the step S8, the test steps of the open prestressed steel bar tension breaking out test without concrete wrapping are as follows: 1) On the static load test bench, install 3 groups of prestressed steel rod anchoring assemblies according to the design reinforcement form and install the anchor pad plate and anchor nut in turn; 2) Preferably, the prestressed steel rod is tensioned by a through-type tensioning jack at a design tensioning force value of 189.4 kN, and the anchor nut is locked for anchoring. After tensioning is completed, the protective plate and protective nut are installed; 3) On the static load test bench, protective covers are arranged at both ends, and a plasma cutting machine is used to perform instantaneous cutting of the prestressed steel rod; 4) The first and second steel rods are cut in turn, and the protection state of the protective plate and protective nut is observed.

[0014] Further, the bridge deck transverse unbonded prestressed steel rod anchorage structure comprises an anchor nut, a protective baffle, an anchor pad plate, a sheath, an unbonded prestressed steel rod, a protective nut and a spiral rib. The protective baffle is arranged at the front end of the anchorage structure, and a plurality of anchor holes are formed in the interior of the protective baffle. The anchor nut is arranged at the anchor hole end of the anchorage structure and clamped on the outer wall of the unbonded prestressed steel rod. The unbonded prestressed steel rod penetrates the interior of the anchor nut and extends into the interior of the sheath. The interior of the anchorage structure is provided with the anchor pad plate. The sheath is arranged at the rear end of the anchorage structure. The protective nut is arranged at the front end of the protective baffle and is threadedly connected with the unbonded prestressed steel rod. The spiral rib is connected to the rear end of the anchor pad plate and is sleeved on the outside of the unbonded prestressed steel rod.

[0015] Further, in the bridge deck transverse unbonded prestressed steel rod anchorage structure, the anchor nut is matched with the spherical countersunk pilot hole arranged in the anchor pad plate.

[0016] Further, the unbonded prestressed steel rod is formed by an online oiling hot extrusion plastic continuous forming process. The sheath is made of high-density polyethylene (PE) resin. The unbonded prestressed rib is used for anticorrosive lubricating grease between the steel rod and the sheath.

[0017] (Three) Beneficial effects The present application provides a bridge deck transverse unbonded prestressed steel rod anchorage structure design method. The following beneficial effects are achieved: 1) The present application provides a bridge deck transverse unbonded prestressed steel rod anchorage structure design method. By matching the spherical end face of the anchor nut with the spherical countersunk pilot hole arranged in the anchor pad plate, self-adaptive adjustment can be achieved during the prestressing process, especially during the curve reinforcement tensioning, thereby ensuring uniform stress, verticality and concentricity of the anchor nut, anchor pad plate and prestressed steel rod, avoiding the generation of an included angle between the anchor nut and the anchor pad plate to cause shear stress damage, and ensuring the contact of the spherical surface even when the steel rod and the anchor pad plate are arranged at a certain angle, which is beneficial to the engineering quality and precision during the prestressing process.

[0018] 2. The present invention provides a design method for a non-bonded prestressed steel rod anchor structure for the transverse direction of bridge panels. The reinforcement takes up little space and is suitable for the reinforcement needs of narrow cross-sections such as bridge panels. The non-bonded structure is simple to construct and does not require pipeline reservation and subsequent grouting. The risk of corrosion and fracture of prestressed tendons under high stress conditions caused by inaccurate pipeline grouting, duct leakage or slurry segregation is eliminated. The non-bonded prestressed steel rods are anchored with supporting threads, with high anchoring accuracy. Precise tensioning once can meet the tensioning control requirements, and the problem of large prestressing loss in medium and short distances is solved.

[0019] 3. The present invention provides a structural design method for non-bonded prestressed steel rod anchors for transverse bridge decks. The non-bonded prestressed steel rods are tensioned by front-end extension rods, without the need to reserve a working length. The tensioning results can be verified, thus realizing the tensioning acceptance of the prestressed tendons and safeguarding the project. The non-bonded prestressed steel rod anchors are equipped with safety protection devices, and there is no risk of accidental breakage and ejection of the prestressed tendons. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the connection of the unbonded prestressed steel rod anchor structure for the transverse side of the bridge deck according to the present invention; Figure 2 This is a schematic diagram of the longitudinal prestressed pipes on the bridge deck and their position layout according to the present invention; Figure 3 This is a schematic diagram of the transverse prestressed pipes on the bridge deck and their position layout according to the present invention; Figure 4 This is a schematic diagram of the layout of the longitudinal and transverse common steel bars of the top plate of the present invention; Figure 5 The transverse prestressed beam arrangement of the bridge deck of the present invention Figure 1 ; Figure 6 The transverse prestressed beam arrangement of the bridge deck of the present invention Figure 2 .

[0021] Among them, 1. Anchor nut; 2. Protective baffle; 3. Anchor plate; 4. Sheath; 5. Unbonded prestressed steel rod; 6. Protective nut; 7. Spiral reinforcement. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the specific embodiments of the present invention to clearly and completely describe the technical solutions in the specific embodiments of the present invention. Obviously, the specific embodiments described are only part of the specific embodiments of the present invention, rather than all the specific embodiments. Based on the specific embodiments of the present invention, all other specific embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Specific implementation method: likeFigures 1-6 As shown, the embodiment of the present application provides a bridge deck transverse unbonded prestressed steel bar anchorage structure design method, comprising the following processes: Step S1. In combination with the wire spacing of the bridge deck, referring to the size parameters of the transverse prestressed flat anchor, the unbonded prestressed steel bar anchorage structure suitable for the transverse prestressed wire arrangement requirements of the bridge deck is designed; Step S2. The concrete crack resistance and local bearing strength of the anchorage structure of the multiple-branch unbonded prestressed steel bar are calculated respectively; In actual application scenarios, the anchorage structure of the multiple-branch unbonded prestressed steel bar can also be set to single-branch or multiple-branch specifications, and is not limited to 2-branch or 3-branch groups; According to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification”, the concrete crack resistance and local bearing strength of the anchorage assembly of the 2-branch group are calculated as follows: 1) The concrete crack resistance calculation under the anchor refers to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification” 5.7.1 The concrete crack resistance under the anchor of φ16-2 steel bar is calculated, 2) The concrete local bearing strength calculation under the anchor refers to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification” 5.7.2 The requirements.

[0024] According to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification”, the concrete crack resistance and local bearing strength of the anchorage assembly of the 3-branch group are calculated as follows: 1) The concrete crack resistance calculation under the anchor refers to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification” 5.7.1 The concrete crack resistance under the anchor of φ16-3 steel bar is calculated, 2) The concrete local bearing strength calculation under the anchor refers to JTG 3362-2018 “Highway Reinforced Concrete and Prestressed Concrete Bridge and Culvert Design Specification” 5.7.2 The requirements.

[0025] Step S3. The anchorage assembly is designed and selected for the spherical angle; In order to achieve the best effect of the spherical angle design of the anchoring assembly, the research and development team members in the design process use finite element analysis, combined with actual test verification, to determine the optimal design angle, and consider the safety redundancy: in the finite element analysis, the limit breaking force of the un-bonded prestressed steel bar is selected for analysis, and there is no abnormality.

[0026] Step S4. Through the analysis of the design drawings, the data of the bridge deck longitudinal prestressed pipe and its position, the transverse prestressed pipe and its position, and the arrangement position of the longitudinal and transverse ordinary steel bars of the top plate are analyzed; The analysis results are shown in Table 1 as follows: Table 1 Data analysis table Step S5. Static load anchoring performance test of the new un-bonded prestressed steel bar anchorage assembly, including: static load anchoring efficiency, limit total strain and limit failure form; According to the requirements of GB / T 14370-2015 "Anchorage, clamp and connector for prestressed tendon", the static load anchoring performance test results are shown in Table 2 as follows: Table 2 Static load anchoring performance test results Test conclusion: the static load anchoring performance meets the requirements of GB / T 14370. Under the test conditions of the limit breaking force of the prestressed steel bar, the failure form is the fracture of the prestressed steel bar, not the failure of the anchorage assembly. The safety of the new anchorage assembly meets the use requirements.

[0027] Step S6. Curve reinforcement feasibility and single-end tension test ① Curve reinforcement feasibility: select two forms of curve reinforcement in the bridge transverse prestress, i.e. curve reinforcement and multi-curve reinforcement, and refer to the representative reinforcement curvature in the design drawings for simulation verification to determine the feasibility of the prestressed steel bar curve reinforcement; ② Prestressed tension test: according to the reinforcement form of the curve reinforcement simulation test in the early stage, the un-bonded prestressed steel bar is laid out to make a concrete model with the same proportion, two reinforcement forms of curvature radius R400x4 bending and curvature radius R600x2 bending are selected, and the prestressed steel bars in different states are numbered and marked. Before the test, the vibrating string anchor cable meter is calibrated to meet the accuracy requirements, ensure the accuracy and effectiveness of the experimental data, and the tension force is preferably set to 190kN, the tension force is generally not more than 70% of the breaking force, and the preferred value is 65%-66%; The test process of the prestressed tension test includes: ①. Steel bar binding and prestressed steel bar layout; ②. Concrete model pouring; ③. Measurement sensor calibration; IV. Simulated tension test.

[0028] The tension test data and conclusions of the curved tendon are shown in Table 3 below: Table 3 Tension test data and conclusions of the curved tendon Step S7. Perform the un-bonded prestressed steel bar concrete model un-protected fracture and channeling test; Step S8. Perform the un-bonded prestressed steel bar protection device safety test, using an open prestressed steel bar tension breaking and channeling test without concrete wrapping; The test steps are as follows: 1) On the static load test bench, install a 3-branch prestressed steel bar anchoring assembly according to the designed tendon arrangement, and sequentially install the anchor pad and anchor nut; 2) Using a through-tensioning jack, select a design tension force value of 189.4 kN to tension the prestressed steel bar, and lock the anchor nut for anchoring. After tensioning is completed, install the protection plate and protection nut; 3) Set protection covers at both ends on the static load test bench. Use a plasma cutting machine to perform instantaneous breaking cutting on the prestressed steel bar; 4) Sequentially cut off the first and second steel bars and observe the protection state of the protection plate and protection nut.

[0029] Test conclusion: The protection device can effectively prevent the risk of accidental fracture and channeling of the prestressed steel bar, and is safe and reliable.

[0030] The bridge deck transverse un-bonded prestressed steel bar anchorage structure includes an anchor nut 1, a protection baffle 2, an anchor pad 3, a sheath 4, an un-bonded prestressed steel bar 5, a protection nut 6, and a spiral tendon 7. The protection baffle 2 is arranged at the front end of the anchorage structure, and a plurality of anchor holes are formed in the interior of the protection baffle 2. The anchor nut 1 is arranged inside the anchor hole of the anchorage structure and clamped on the outer wall of the un-bonded prestressed steel bar 5. The un-bonded prestressed steel bar 5 penetrates the interior of the anchor nut 1 and extends into the interior of the sheath 4. The anchor pad 3 is arranged in the interior of the anchorage structure, and the sheath 4 is arranged at the rear end of the anchorage structure. The protection nut 6 is arranged at the front end of the protection baffle 2 and threadedly connected with the un-bonded prestressed steel bar 5. The spiral tendon 7 is connected to the rear end of the anchor pad 3 and sleeved on the outside of the un-bonded prestressed steel bar 5.

[0031] In the bridge deck slab transverse unbonded prestressed steel bar anchorage structure, the anchor nut adopts spherical end face and spherical countersunk guide through hole matched with the anchor pad 3. In the prestress application process, especially in the curve tendon tensioning, self-adaptive adjustment can be completed, the uniform stress, vertical and concentricity indexes of the anchor nut, anchor pad and prestressed steel bar are ensured, so that the shear stress damage caused by the included angle between the anchor nut and the anchor pad is avoided, even if the steel bar and the anchor pad are arranged at a certain angle, the spherical surface contact can be ensured, which is beneficial to the engineering quality and precision in the prestress application process.

[0032] The unbonded prestressed steel bar adopts online oil coating hot extrusion continuous forming process, the sheath adopts high density polyethylene PE resin, and the unbonded prestressed tendon is used between the steel bar and the sheath. Corrosion-resistant lubricating grease is used. The unbonded prestressed steel bar has double corrosion resistance, can avoid the corrosion of concrete chloride ions on the steel bar, and can avoid the possible problems of insufficient grouting and slurry segregation of prestressed pipe grouting, which can cause corrosion of prestressed tendons under high stress state, and can cause safety accidents such as rupture and collapse of components.

[0033] In the application, the tendon occupies small space, is suitable for narrow section tendon demand such as bridge deck slab, adopts unbonded structure, and is simple to construct, does not need pipe reservation and later grouting, avoids the risk of corrosion and rupture of prestressed tendons under high stress state caused by insufficient grouting and slurry segregation of pipe grouting, and adopts supporting type thread anchoring, high anchoring precision, and one-time accurate tensioning can meet the tensioning control requirements.

[0034] In the application, the unbonded prestressed steel bar adopts front end extension rod tensioning, does not need to reserve working length, the tensioning result can be verified, realizes tensioning acceptance of prestressed tendons, and provides safety protection for engineering safety, the unbonded prestressed steel bar anchorage device is provided with a safety protection device, and there is no risk of accidental rupture and outflow of prestressed tendons.

[0035] Although the specific embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the specific embodiments without departing from the principles and spirits of the present application, the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. Design method for the transverse unbonded prestressed steel rod anchor structure of the bridge deck, characterized by: The following processes are included: Step S1. Based on the reinforcement space of the bridge deck and the dimension parameters of the transverse prestressed flat anchor, a non-bonded prestressed steel rod anchor structure suitable for the transverse prestressed reinforcement requirements of the bridge deck is designed. Step S2. Checking and calculating the crack resistance and local compressive strength of the concrete under the anchor for each of the multiple groups of unbonded prestressed steel rod anchor structures; Step S3. Anchoring assembly and spherical angle design selection; Step S4. By analyzing the design drawings, analyze the data of the longitudinal prestressed pipes and their locations on the bridge deck, the transverse prestressed pipes and their locations, and the longitudinal and transverse ordinary steel reinforcement layout positions on the top slab; Step S5. Conducting static load anchoring performance testing on the novel unbonded prestressed steel rod anchor assembly, including static load anchoring efficiency, ultimate total strain, and ultimate failure mode; Step S6. Conduct curve reinforcement feasibility and single-end tensioning tests ① Feasibility of curved reinforcement: Two types of reinforcement layout, curved reinforcement layout and multi-curved reinforcement layout, were selected for the transverse prestressing of the bridge deck. The feasibility of curved reinforcement layout of prestressed steel bars was determined through simulation verification with reference to representative reinforcement curvatures in the design drawings. ② Prestressed tension test: Unbonded prestressed steel bars were laid out according to the reinforcement pattern of the previous curved reinforcement simulation test to make a concrete scale model. Two reinforcement patterns were adopted: a curvature radius of R400×4 bends and a curvature radius of R600×2 bends. The prestressed steel bars in different states were numbered and identified. The vibrating wire anchor meter was calibrated before the test to meet the accuracy requirements and ensure the accuracy and validity of the experimental data. The tension force was preferably set to 190kN. Step S7. Conducting an unprotected fracture and ejection test on an unbonded prestressed steel bar concrete model; Step S8. Conduct a safety test on the unbonded prestressed steel bar protective device, using an open prestressed steel bar tensioning and breaking test without concrete wrapping.

2. The method for designing a non-bonded prestressed steel rod anchor structure for a bridge deck according to claim 1, characterized in that: In step S2, the crack resistance and local compressive strength of the concrete under the anchor of a group of two anchor assemblies are checked and calculated as follows: 1) The crack resistance of concrete under anchor is checked in accordance with Article 5.7.1 of JTG 3362-2018 "Design Specifications for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts" Take the concrete crack resistance under the φ16-2 steel rod anchor for inspection and calculation. Meet regulatory requirements; 2) The local compressive strength of the concrete under the anchor is calculated in accordance with Article 5.7.2 of JTG 3362-2018 "Design Specifications for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts" Meet the specification requirements.

3. The method for designing a non-bonded prestressed steel rod anchor structure for a transverse bridge deck according to claim 1, characterized in that: In step S2, the crack resistance and local compressive strength of the concrete under the anchor of each group of three anchor assemblies are checked and calculated as follows: 1) The crack resistance of concrete under the anchor is checked in accordance with Article 5.7.1 of JTG 3362-2018, Specification for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts: Take the concrete crack resistance under the φ16-3 steel rod anchor for inspection and calculation. Meet regulatory requirements; 2) The local compressive strength of the concrete under the anchor is calculated in accordance with Article 5.7.2 of JTG 3362-2018 "Design Specifications for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts" Meet the specification requirements.

4. The method for designing a non-bonded prestressed steel rod anchor structure for a transverse bridge deck according to claim 1, characterized in that: In step S3, in order to achieve the best effect in the spherical angle design of the anchor component, the R&D team members used finite element analysis and combined it with actual test verification to determine the optimal design angle during the design process, and took into account safety redundancy: during the finite element analysis, the force value applied under the simulated working condition was selected to analyze the ultimate breaking force of the unbonded prestressed steel rod, and no abnormalities were found.

5. The method for designing a transverse unbonded prestressed steel rod anchor structure for a bridge deck according to claim 1, characterized in that: In step S6, the prestressed tension test process includes: ①.Reinforcement binding and prestressed steel bar layout; ②. Concrete model pouring; ③. Calibration of measuring sensors; ④.Simulated tension test.

6. The method for designing a non-bonded prestressed steel rod anchor structure for a bridge deck according to claim 1, characterized in that: In step S8, the test steps for the tension fracture and burst test of an open prestressed steel bar without concrete encapsulation are as follows: 1) On the static load test bench, install three prestressed steel rod anchor assemblies in a group according to the designed reinforcement layout and install the anchor plate and anchor nut in sequence; 2) Use a through-type tensioning jack, preferably according to the designed tensioning force of 189.4kN, to tension the prestressed steel rods, and tighten the anchor nuts for anchoring. After tensioning is completed, install the protective plates and protective nuts; 3) Install protective covers at both ends of the static load test bench; Use plasma cutting machine to perform instantaneous cutting of prestressed steel bars; 4) Cut off the first and second steel rods in turn and observe the protective status of the protective plate and protective nut.

7. The method for designing a transverse unbonded prestressed steel bar anchor structure for a bridge deck according to claim 1, comprising a transverse unbonded prestressed steel bar anchor structure for a bridge deck, characterized in that: The anchor structure comprises an anchor nut (1), a protective baffle (2), an anchor plate (3), a sheath (4), an unbonded prestressed steel rod (5), a protective nut (6) and a spiral rib (7); the protective baffle (2) is arranged at the front end of the anchor structure, and a plurality of anchor holes are opened inside the protective baffle (2); the anchor nut (1) is arranged at the end of the anchor hole of the anchor structure and is clamped on the outer wall of the unbonded prestressed steel rod (5); the unbonded prestressed steel rod (5) passes through the inside of the anchor nut (1) and extends into the inside of the sheath (4); an anchor plate (3) is arranged inside the anchor structure; the sheath (4) is arranged at the rear end of the anchor structure; the protective nut (6) is arranged at the front end of the protective baffle (2) and is threadedly sleeved with the unbonded prestressed steel rod (5); the spiral rib (7) is connected to the rear end of the anchor plate (3) and sleeved on the outside of the unbonded prestressed steel rod (5).

8. The method for designing a transverse unbonded prestressed steel rod anchor structure for a bridge deck according to claim 7, characterized in that: In the bridge deck transverse unbonded prestressed steel rod anchor structure, the anchor nut adopts a spherical end surface and cooperates with a spherical countersunk guide through hole provided in the anchor pad (3).

9. The method for designing a transverse unbonded prestressed steel rod anchor structure for a bridge deck according to claim 7, characterized in that: The unbonded prestressed steel rod is formed by an online oil-coated hot extrusion continuous molding process, the sheath is made of high-density polyethylene PE resin, and anti-corrosion grease for unbonded prestressed tendons is used between the steel rod and the sheath.

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