A reinforcement structure and reinforcement method for lifting a cantilever plate on a bridge deck

Abstract

The present invention relates to a reinforcement structure and reinforcement method for improving a bridge deck cantilever plate, wherein the bridge deck cantilever plate includes an end portion of the bridge deck cantilever plate for fixing a newly built guardrail and a root portion of the bridge deck cantilever plate, and is characterized in that the reinforcement structure includes a composite steel member extending from the end portion of the bridge deck cantilever plate to the root portion of the bridge deck cantilever plate, and the composite steel member includes at least two transverse composite steel members connected to the bridge deck cantilever plate and the newly built guardrail and a longitudinal perforated steel plate connecting each transverse composite steel member. Compared with the prior art, the advantage of the present invention is that the reinforcement structure of the bridge deck cantilever plate based on improving the anti-collision level of the bridge guardrail, while improving the anti-collision capability of the guardrail, the composite steel member also enables the bridge deck cantilever plate to be reinforced to improve the bending bearing capacity of the bridge deck cantilever plate; from the perspective of construction performance, only partial or temporary traffic closure is required, which reduces the impact on traffic and reduces construction risks.

Description

Technical Field

[0001] The present invention relates to the technical field of reinforcement of bridge deck cantilever plates, and in particular to a reinforcement structure and a reinforcement method of a bridge deck cantilever plate based on improving the anti-collision level of bridge guardrails. Background Art

[0002] With the rapid development of the economy and society, and the increase in the number, load, and speed of vehicles, the public has placed higher demands on the collision prevention capabilities of bridge guardrails. At the same time, my country has a large number of bridges, with guardrails of varying types and collision prevention capabilities. Some guardrails no longer meet existing protection needs, impacting highway operational safety and urgently requiring renovation and improvement. Among these, some bridges have low existing guardrail crashworthiness ratings and insufficient load-bearing capacity for the bridge deck cantilever slabs. Furthermore, these bridges often cross highways, railways, or first-level protection zones for urban drinking water sources, necessitating a significant improvement in their safety and protection capabilities. In addition to the guardrail renovation and upgrade, the bridge deck cantilever slabs must also be reinforced to increase their load-bearing capacity. Conventional methods for improving the bearing capacity of cantilever plates on bridge decks, such as removing the cantilever plates and building new ones, often require long construction times, are difficult, and are expensive, or the height of the cantilever plates can be increased. Reference may be made to a Chinese utility model with patent number 201721675829.7 (authorization announcement number CN207597282U), entitled "A Steel Support Structure for Reinforced Flange Plates of Large Cantilever Bridges," which discloses a steel support structure for reinforced flange plates of large cantilever bridges, supported on the lower edge of the cantilever and the outer side of the web of the bridge, comprising a base plate, rib plates, and wing plates. The base plate has a special shape that fits the lower edge of the cantilever and the outer side of the web, one side of the rib plate has a special edge shape that fits the base plate, one side of the special edge rib plate is welded to the base plate, the other side of the rib plate is straight, and one side of the straight edge rib plate is welded to the wing plate, the base plate is fixed to the lower edge of the cantilever and the outer side of the web of the bridge by anchor bolts and poured steel glue, and a number of decorative holes are provided on the rib plate. The bridge's large cantilever flange plate reinforced steel supporting structure can reduce the impact on the original bridge structure and stress conditions during the bridge widening and reconstruction process. Although it can reduce the impact of traffic on the existing bridge deck and significantly improve the stiffness and stress reserve of the cantilever structure, the construction process and operation are all located at the lower edge of the cantilever. The construction is difficult and the quality is difficult to guarantee, and there are great safety hazards. Therefore, it is an urgent problem to adopt a scientific and reasonable method to improve the bearing capacity of the bridge deck cantilever plate during the guardrail reconstruction process to restore the normal operation of the bridge in a timely manner and reduce the impact on people's travel. Summary of the Invention

[0003] The first technical problem to be solved by the present invention is to provide a reinforcement structure for the cantilever plate of the lifting bridge deck, which is convenient to construct, safe and reliable, and has little hidden danger in construction safety, in view of the above-mentioned existing technical status.

[0004] The second technical problem to be solved by the present invention is to provide a reinforcement method using the above reinforcement structure in response to the above-mentioned existing technical status.

[0005] In order to solve the first technical problem, the technical solution adopted by the present invention is: the reinforcement structure of the bridge deck cantilever plate is lifted, and the bridge deck cantilever plate includes an end of the bridge deck cantilever plate for fixing the newly built guardrail and the root of the bridge deck cantilever plate, and is characterized in that: the reinforcement structure includes a composite steel member extending from the end of the bridge deck cantilever plate to the root of the bridge deck cantilever plate, and the composite steel member includes at least two transverse composite steel members for connecting with the bridge deck cantilever plate and the newly built guardrail and a longitudinal perforated steel plate connecting each transverse composite steel member, wherein each transverse composite steel member is arranged at intervals along the longitudinal bridge direction of the bridge deck cantilever plate.

[0006] Furthermore, each of the transverse composite steel members includes a bottom steel plate arranged in the transverse bridge direction from the end to the root of the bridge deck cantilever plate, and a transverse open-hole steel member vertically connected to the center position of the bottom steel plate.

[0007] In order to strengthen the bearing capacity of the bridge deck cantilever plate, preferably, the bottom steel plate continues to extend in the transverse direction of the bridge where the root of the bridge deck cantilever plate is located, and the extension cutoff point of the bottom steel plate must meet the following requirements: that is, the distance from the root of the bridge deck cantilever plate is not less than ( )mm, where is the design value of tensile strength of bottom steel plate, is the cross-sectional area of ​​the bottom steel plate, is the design value of the bond strength between the bottom steel plate and concrete, The total width of the bottom steel plate is pasted within the plate width of 1m.

[0008] In order to ensure that the bottom steel plate has the function of strengthening the bearing capacity of the bridge deck cantilever plate while also fixing the newly built guardrail, preferably, the bottom steel plate has a starting portion corresponding to the end of the bridge deck cantilever plate, and a welding portion for welding to the vertical main reinforcement of the newly built guardrail is left between the longitudinal perforated steel plate and the starting portion.

[0009] Furthermore, the distance d between the starting portion of the bottom steel plate and the end portion of the bridge deck cantilever plate is 5 mm.

[0010] Among them, the selection of transversely perforated steel components can be considered in combination with the thickness of the cast-in-place concrete layer of the bridge deck. Preferably, the transversely perforated steel components can be selected from any one of the following: transversely perforated steel plates, transversely perforated channel steels, transversely perforated I-beams and transversely perforated angle steels.

[0011] To solve the second technical problem, the present invention further provides a reinforcement method for a reinforcement structure using the above-mentioned lifting bridge deck cantilever plate, which is characterized by comprising the following steps:

[0012] a. Calculate the load-bearing capacity of the bridge deck cantilever slab based on the improved crashworthiness of the newly built guardrail, and then selectively reinforce the bridge deck cantilever slab;

[0013] b. Determine the increased bearing capacity of the cantilever slab of the bridge deck, and thereby determine the specifications, models, and spacing of the bottom steel plate, transverse perforated steel member, and longitudinal perforated steel plate in the composite steel member;

[0014] c. Milling and chiseling away the original asphalt pavement and the original concrete pavement within the reinforcement range of the cantilever slab of the bridge deck, while retaining the transverse reinforcement of the original concrete pavement;

[0015] d. Determine the location for chemical anchor bolts and drill holes. Use chemical anchor bolts and adhesive to fix the bottom steel plate and transversely perforated steel members of the specifications, models, and spacing determined in step b to the top surface of the bridge deck cantilever plate.

[0016] e. Welding the longitudinal perforated steel plate of the determined specifications and models in step b, the bottom steel plate and the transverse perforated steel member in step d into the integral composite steel member;

[0017] f. Laying a steel mesh for the concrete pavement of the cantilever slab of the bridge deck, the steel mesh being laid on the basis of the combined steel member described in step e, and being achieved with the aid of at least two longitudinal steel bars for passing through the reserved holes of the transverse perforated steel member and at least two transverse steel bars for passing through the reserved holes of the longitudinal perforated steel plate;

[0018] g. Based on step f, a new cast-in-place concrete layer of the bridge deck is poured to form a steel-concrete composite section with the bridge deck cantilever slab;

[0019] h. Welding the vertical main reinforcement of the newly constructed guardrail to the welded portion of the combined steel member in step e;

[0020] i. After the cast-in-place concrete layer of the new bridge deck in step g has been cured to the design strength, tie the remaining steel bars of the new guardrail and cast the concrete of the new guardrail in a formwork;

[0021] j. Newly paved asphalt concrete pavement within the cantilever slab reinforcement area of ​​the bridge deck;

[0022] k. Resume normal traffic.

[0023] In order to strengthen the connection between the bottom steel plate and the bridge deck cantilever plate, preferably, the chemical anchor bolts in step d are M12 chemical anchor bolts, the implantation depth of the chemical anchor bolts is ≥100 mm, and each bottom steel plate is provided with two groups of chemical anchor bolts, each group of chemical anchor bolts is separated by a transverse open steel member, wherein each group of chemical anchor bolts has two, and are anchored near the welding part of the bottom steel plate and near the extension position of the bottom steel plate respectively.

[0024] Furthermore, the bottom steel plate in step d has a thickness of 6 mm to 10 mm and a width of 160 mm to 220 mm, and the transversely perforated steel member has a thickness of 6 mm to 10 mm and a vertical height of 70 mm to 72 mm.

[0025] Furthermore, the thickness of the longitudinal perforated steel plate in step e is 6 mm to 10 mm, and the vertical height is the same as that of the transverse perforated steel member, that is, 70 mm to 72 mm.

[0026] Compared with the prior art, the advantages of the present invention are that the reinforcement structure of the bridge deck cantilever plate based on improving the anti-collision level of the bridge guardrail is, from the perspective of structural stress, after replacing the new guardrail, while improving the anti-collision ability of the guardrail, the combined steel components can reinforce the bridge deck cantilever plate to improve the bending bearing capacity of the bridge deck cantilever plate; and from the perspective of construction performance, only partial or temporary closure of traffic is required to complete the reinforcement process in a short time, which reduces the impact on traffic. In addition, the entire construction process is carried out on the bridge deck cantilever plate, which has the characteristics of convenient construction and small construction safety hazards. The present invention also provides a method of applying the above reinforcement structure A reinforcement method is provided, which fixes a composite steel member on the top of a bridge deck cantilever plate, and at the same time forms a whole with the composite steel member through longitudinal reinforcement passing through reserved holes of the transverse open steel member and transverse reinforcement passing through reserved holes of the longitudinal open steel plate, and welds the vertical main reinforcement of the newly built guardrail to the composite steel member or the newly installed transverse bridge deck reinforcement, and then pours a cast-in-place layer of bridge deck concrete to form a steel-concrete composite section, which is subjected to force together with the bridge deck cantilever plate, thereby improving the bending stiffness of the bridge deck cantilever plate, achieving the purpose of improving the bearing capacity of the bridge deck cantilever plate, and at the same time strengthening the connection between the newly built guardrail and the bridge deck cantilever plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of each transverse composite steel member fixed to the top of the bridge deck cantilever plate in Example 1 of the present invention;

[0028] Figure 2 This is a schematic structural diagram of the connection between the bottom steel plate and the transversely perforated steel plate in Example 1 of the present invention;

[0029] Figure 3 This is a schematic structural diagram of a longitudinally perforated steel plate in Example 1 of the present invention;

[0030] Figure 4 A top view of a composite steel member fixed to the top of a cantilever plate on a bridge deck in Example 1 of the present invention;

[0031] Figure 5 for Figure 4 Sectional view in the AA direction (connected with the newly built guardrail);

[0032] Figure 6 for Figure 4 Cross-section view along the middle BB direction (connected with the newly built guardrail);

[0033] Figure 7 This is a structural schematic diagram of the connection between the bottom steel plate and the transverse perforated channel steel in Example 2 of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments. Example

[0035] like Figures 1 to 6 The figure shows a preferred embodiment of the present invention. This embodiment provides a reinforcement structure for a bridge deck cantilever slab 1, designed to improve the crashworthiness of a bridge guardrail. The bridge deck cantilever slab 1 includes an end 1a for securing a newly built guardrail 120 and a base 1b. The reinforcement structure comprises a composite steel member extending from the end 1a to the base 1b of the bridge deck cantilever slab. The composite steel member comprises at least two transverse composite steel members for connecting the bridge deck cantilever slab 1 and the newly built guardrail 120, and a longitudinal perforated steel plate 20 connecting the transverse composite steel members. The transverse composite steel members are spaced apart along the longitudinal direction of the bridge deck cantilever slab 1. From a structural perspective, this reinforcement structure for a bridge deck cantilever slab, designed to improve the crashworthiness of a bridge guardrail, improves the guardrail's crashworthiness after replacing the newly built guardrail 120. Furthermore, the composite steel members reinforce the bridge deck cantilever slab 1, thereby increasing its bending bearing capacity. Among them, each transverse composite steel member includes a bottom steel plate 9 arranged along the transverse bridge direction from the end 1a to the root 1b of the bridge deck cantilever plate 1, and a transverse open-hole steel member vertically connected to the center position of the bottom steel plate 9. The transverse open-hole steel member in this embodiment is a transverse open-hole steel plate 30.

[0036] In order to reinforce the bridge deck cantilever plate 1, the bottom steel plate 9 continues to extend in the transverse direction of the bridge where the root 1b of the bridge deck cantilever plate 1 is located. The extension cutoff point of the bottom steel plate 9 must meet the following requirements: that is, the distance from the root 1b of the bridge deck cantilever plate 1 is not less than ( )mm, where is the design value of tensile strength of bottom steel plate, is the cross-sectional area of ​​the bottom steel plate, is the design value of the bond strength between the steel plate and concrete, The total width of the bottom steel plate 9 within the 1m slab width is defined. The bottom steel plate 9 also has a starting portion corresponding to the end 1a of the cantilever slab 1. A weld 93 is provided between the longitudinally perforated steel plate 20 and the starting portion 92 for welding to the vertical main reinforcement of the newly constructed guardrail 120. Furthermore, the distance d between the starting portion 92 of the bottom steel plate 9 and the end 1a of the cantilever slab 1 is 5mm.

[0037] The present invention also provides a reinforcement method for a bridge deck cantilever plate reinforcement structure based on improving the anti-collision level of a bridge guardrail, comprising the following steps:

[0038] a. Calculating the bearing capacity of the bridge deck cantilever plate 1 based on the improved anti-collision level of the newly built guardrail 120, and then selectively reinforcing the bridge deck cantilever plate 1;

[0039] b. Determine the increased bearing capacity of the cantilever slab 1 of the bridge deck, and then determine the specifications, models, and arrangement spacing of the bottom steel plate 9, the transverse perforated steel plate 30, and the longitudinal perforated steel plate 20 in the composite steel member;

[0040] c. Milling and chiseling away the original asphalt pavement layer 4 and the original concrete pavement layer 5 within the reinforcement range of the bridge deck cantilever slab 1, retaining the transverse reinforcement of the original concrete pavement layer;

[0041] d. Determine the implantation position of the chemical anchor bolts 12 and drill holes. Use the chemical anchor bolts 12 and the adhesive steel structure to fix the bottom steel plate 9 and the transverse open hole steel member of the specifications, models and arrangement spacing determined in step b to the top surface of the bridge deck cantilever plate 1; the chemical anchor bolts 12 in step d use M12 chemical anchor bolts, the implantation depth of the chemical anchor bolts 12 is ≥100 mm, and two groups are provided for each bottom steel plate 9, and each group of two are fixed by chemical anchor bolts, wherein each group has two chemical anchor bolts, and they are anchored near the welding part 93 of the bottom steel plate and near the extension position of the bottom steel plate 9, wherein the thickness of the bottom steel plate 9 in step d is 6 mm to 10 mm, the width is 160 mm to 220 mm, the thickness of the transverse open hole steel member is 6 mm to 10 mm, and the vertical height is 70 mm to 72 mm.

[0042] e. Weld the longitudinal perforated steel plate 20 of the determined specifications in step b with the bottom steel plate 9 and the transverse perforated steel member in step d into an integral composite steel member; the thickness of the longitudinal perforated steel plate 20 in step e is 6 mm to 10 mm, and the vertical height is the same as that of the transverse perforated steel member, that is, 70 mm to 72 mm.

[0043] f. Laying the steel mesh of the concrete pavement layer of the cantilever slab 1 of the bridge deck. The laying of the steel mesh is based on the assembly of the steel members in step e and is achieved by using at least two longitudinal steel bars 70 for passing through the reserved holes of the transverse perforated steel members and at least two transverse steel bars 80 for passing through the reserved holes of the longitudinal perforated steel plate 20;

[0044] g. Based on step f, a new bridge deck concrete cast-in-place layer 13 is poured to form a steel-concrete composite section with the bridge deck cantilever plate 1;

[0045] h. Weld the vertical main reinforcement of the newly constructed guardrail 120 to the welded portion 93 of the combined steel member in step e;

[0046] i. After the new bridge deck concrete cast-in-place layer 13 in step g is cured to the design strength, the remaining steel bars of the new guardrail 120 are tied and the concrete of the new guardrail 120 is poured;

[0047] j. Newly pave the asphalt concrete pavement layer 14 within the reinforcement area of ​​the cantilever slab 1 of the bridge deck;

[0048] k. Resume normal traffic.

[0049] In summary, the specific construction method of the reinforcement method of the bridge deck cantilever plate based on improving the anti-collision level of the bridge guardrail must first determine the increase in the bearing capacity of the bridge deck cantilever plate 1, and then determine the specifications and models of the combined steel components, the layout spacing and the requirements of the steel bars and chemical anchors 12. The bearing capacity of the bridge deck cantilever plate 1 is calculated: first, in accordance with the relevant provisions of the "Design Rules for Highway Traffic Safety Facilities" (JTG / T D81) and the "Technical Guidelines for the Special Action to Improve the Safety Protection Capacity of Highway Bridges" (March 2019), determine the anti-collision level 120 of the newly built guardrail of the old bridge, and verify whether the bearing capacity of the bridge deck cantilever plate after the anti-collision level of the guardrail is improved meets the requirements of the specification.

[0050] The specifications of the combined steel components are:

[0051] The bottom steel plate 9 of the composite steel member should be made of Q355 steel; weathering steel, carbon steel and low alloy high strength steel can also be used; the thickness of the bottom steel plate should be 6mm to 10mm, and the width should be 160mm to 220mm. The adhesive used to stick the bottom steel plate 9 should be Class A steel structure adhesive; the thickness of the longitudinal perforated steel plate 20 should be 6mm to 10mm, and the width should be the same as the width of the transverse perforated steel plate 30. The longitudinal segment length is generally 5 to 9m; the bottom steel plate 9, the transverse perforated steel plate 30 and the longitudinal perforated steel plate 20 should be selected well, and the bottom steel plate 9 should extend to the inside of the root of the bridge deck cantilever plate 1, and its cutoff point should be no less than ( ) mm, where is the design value of tensile strength of bottom steel plate, is the cross-sectional area of ​​the bottom steel plate, is the design value of the bond strength between the steel plate and concrete (refer to Table 6.2.5 of JTG / T J22-2008), The total width of the bottom steel plate within the 1m plate width;

[0052] Then determine the arrangement spacing of the transverse composite steel members: the longitudinal arrangement spacing of the transverse composite steel members along the bridge deck cantilever plate 1 is preferably 500mm to 1000mm;

[0053] Then, the requirements for the steel bars used in laying the steel mesh are determined: ribbed steel bars with a grade of no less than HRB400 and a diameter of 12mm are used; the steel bars are welded together, and the weld length meets the specification requirements; the newly added longitudinal steel bars 70 pass through the reserved holes of the transverse perforated steel plate 30; the newly added transverse steel bars 80 pass through the reserved holes of the longitudinal perforated steel plate 20;

[0054] Then determine the requirements for chemical anchor bolts: use M12 chemical anchor bolts 12 and Class A rebar embedding glue; the implantation depth of chemical anchor bolts is ≥100mm; and two groups are set for each bottom steel plate 9, and each group of two is fixed by chemical anchor bolts 12, among which, each group of chemical anchor bolts 2 has two, and are anchored near the welding part 93 of the bottom steel plate 9 and near the extension position of the bottom steel plate 9 respectively; when implanting the chemical anchor bolts 12, pay attention to avoid the steel bars in the original beam and slab 200, and the position can be adjusted appropriately according to actual conditions.

[0055] Finally, the requirements for the cast-in-place concrete layer of the new bridge deck were determined: Generally, ordinary C40 and above concrete is used; if there is a need for rapid construction due to limited construction period, new concrete materials can be used, such as fast-hardening ultra-high toughness concrete.

[0056] like Figure 1 As shown, taking three composite steel members as an example, such as the first transverse composite steel member 100, the second transverse composite steel member 101 and the third transverse composite steel member 102, the longitudinal arrangement spacing along the bridge deck cantilever plate 1 is 800 mm as an example for description, the first transverse composite steel member 100, the second transverse composite steel member 101 and the third transverse composite steel member 102 all have their own bottom steel plate 9 and transverse perforated steel plate 30, and the first transverse composite steel member 100, the second transverse composite steel member 101 and the third transverse composite steel member 102 are connected by implanting chemical anchor bolts 12 and adhesive. The bottom steel plate 9 and the transverse perforated steel plate 30 of the composite steel member 102 are fixed to the top of the bridge deck cantilever plate 1, and then the first transverse composite steel member 100, the second transverse composite steel member 101 and the third transverse composite steel member 102 are connected together through the longitudinal perforated steel plate 20. Next, the steel mesh is laid with the help of a plurality of longitudinal steel bars 70 for passing through the reserved holes of the transverse perforated steel plate 30 and a plurality of transverse steel bars 80 for passing through the reserved holes of the longitudinal perforated steel plate 20, and then the newly built guardrail 120 is welded to the welding portion 93 of each bottom steel plate 9, wherein, reference can be made to Figure 5 and 6The newly built guardrail 120 includes a first guardrail vertical main reinforcement 1201 corresponding to the starting part 92 of each bottom steel plate 9, a second guardrail vertical main reinforcement 1202 corresponding to the longitudinal perforated steel plate 20, and a third guardrail vertical main reinforcement 1203 corresponding to the bottom steel plate 9. During welding, the first guardrail vertical main reinforcement 1201 is directly welded to the welding part 93 of the bottom steel plate 9 or the transverse reinforcement 80 of the newly built bridge deck, and the transverse reinforcement 80 of the newly built bridge deck is welded and fixed to the transverse reinforcement of the original concrete pavement layer. The second guardrail vertical main reinforcement 1202 is directly welded to the longitudinal perforated steel plate 20, and the third guardrail vertical main reinforcement 1203 is directly welded to the bottom steel plate 9. Finally, the bridge deck concrete cast-in-place layer 13 is poured to form a steel-concrete composite section, which is subjected to force together with the bridge deck cantilever plate 1, thereby improving the bending stiffness of the bridge deck cantilever plate 1 and achieving the purpose of improving the bearing capacity of the bridge deck cantilever plate 1. Example

[0057] The structure is basically the same as that of Example 1, the only difference being that the transverse hole steel member is a transverse hole channel steel 40, and the channel steel is preferably selected from types 6.3, 6.5, 8 and 10. Figure 7 shown. Example

[0058] The structure is basically the same as that of Example 1, with the only difference being that the transversely perforated steel member is a transversely perforated I-beam. Example

[0059] The structure is basically the same as that of Example 1, with the only difference being that the transverse hole steel member is a transverse hole angle steel.

Claims

1. A reinforcement structure for lifting a bridge deck cantilever plate, the bridge deck cantilever plate comprising an end portion (1a) of the bridge deck cantilever plate (1) for fixing a newly built guardrail (120) and a root portion (1b) of the bridge deck cantilever plate (1), characterized in that: The reinforcement structure comprises a composite steel member extending from an end portion (1a) of the bridge deck cantilever plate (1) to a root portion (1b) of the bridge deck cantilever plate (1), the composite steel member comprising at least two transverse composite steel members for connecting to the bridge deck cantilever plate (1) and a newly constructed guardrail (120) and a longitudinal perforated steel plate (20) connecting the transverse composite steel members, wherein the transverse composite steel members are arranged at intervals along the longitudinal direction of the bridge deck cantilever plate (1); Each of the transverse composite steel members comprises a bottom steel plate (9) arranged in the transverse bridge direction from the end (1a) to the root (1b) of the bridge deck cantilever plate (1), and a transverse open-hole steel member vertically connected to the center of the bottom steel plate (9); The bottom steel plate (9) continues to extend in the transverse direction of the bridge where the root (1b) of the bridge deck cantilever plate (1) is located. The position of the extension cutoff point of the bottom steel plate (9) must meet the following requirements: that is, the distance from the root (1b) of the bridge deck cantilever plate (1) is not less than Among them, f sp is the design value of tensile strength of bottom steel plate, A sp is the cross-sectional area of ​​the bottom steel plate, τ p is the design value of the bond strength between the steel plate and concrete, b p The total width of the bottom steel plate (9) pasted within the 1m plate width; The bottom steel plate (9) has a starting portion (92) corresponding to the end portion (1a) of the bridge deck cantilever plate (1), and a welding portion (93) for welding to the vertical main reinforcement of the newly built guardrail (120) is reserved between the longitudinal perforated steel plate (20) and the starting portion (92).

2. The reinforcement structure of the cantilever plate of the lifting bridge deck according to claim 1 is characterized in that: The distance d between the starting portion (92) of the bottom steel plate (9) and the end portion (1a) of the bridge deck cantilever plate (1) is 5 mm.

3. The reinforcement structure of the cantilever plate of the lifting bridge deck according to any one of claims 1 to 2, characterized in that: The transversely perforated steel member can be selected from any one of the following: a transversely perforated steel plate (30), a transversely perforated channel steel (40), a transversely perforated I-beam, and a transversely perforated angle steel.

4. A reinforcement method for a reinforcement structure using a cantilever plate of a lifting bridge deck as claimed in any one of claims 1 to 3, characterized in that: The following steps are included: a. calculating the bearing capacity of the bridge deck cantilever plate (1) according to the improvement of the anti-collision level of the newly built guardrail (120), and then selectively reinforcing the bridge deck cantilever plate (1); b. Determine the value of the load-bearing capacity increase of the bridge deck cantilever plate (1), and then determine the specifications and arrangement spacing of the bottom steel plate (9), the transverse perforated steel member, and the longitudinal perforated steel plate (20) in the composite steel member; c. milling and chiseling away the original asphalt pavement layer (4) and the original concrete pavement layer (5) within the reinforcement range of the bridge deck cantilever plate (1), and retaining the transverse reinforcement of the original concrete pavement layer; d. Determine the implantation position of the chemical anchor bolt (12) and drill holes, and use the chemical anchor bolt (12) and adhesive to fix the bottom steel plate (9) and the transverse open hole steel member of the determined specifications and arrangement spacing in step b to the top surface of the bridge deck cantilever plate (1); e. Welding the longitudinal perforated steel plate (20) of the determined specifications and models in step b, the bottom steel plate (9) and the transverse perforated steel member in step d into the integral composite steel member; f. Laying a steel mesh for the concrete pavement layer of the cantilever slab (1) of the bridge deck, wherein the laying of the steel mesh is based on the combined steel member described in step e and is achieved by means of at least two longitudinal steel bars (70) for passing through the reserved holes of the transverse perforated steel member and at least two transverse steel bars for passing through the reserved holes of the longitudinal perforated steel plate (20); g. Based on step f, a new bridge deck concrete cast-in-place layer (13) is poured to form a steel-concrete composite section with the bridge deck cantilever plate (1); h. Welding the vertical main reinforcement of the newly constructed guardrail (120) to the welded portion (93) of the combined steel member in step e; i. After the new bridge deck concrete cast-in-place layer (13) in step g is cured to the design strength, the remaining steel bars of the new guardrail (120) are tied and the concrete of the new guardrail (120) is poured; j. newly paved asphalt concrete pavement layer (14) within the reinforcement area of ​​the cantilever slab (1) of the bridge deck; k. Resume normal traffic.

5. The reinforcement method according to claim 4, characterized in that: The chemical anchor bolts (12) in step d are M12 chemical anchor bolts, the implantation depth of the chemical anchor bolts (12) is ≥100 mm, and each bottom steel plate (9) is provided with two groups of chemical anchor bolts (12), each group of chemical anchor bolts (12) is separated by a transverse open-hole steel member, wherein each group of chemical anchor bolts (12) has two, and are anchored near the welding portion (93) of the bottom steel plate (9) and near the extension position of the bottom steel plate (9), respectively.

6. The reinforcement method according to claim 5, characterized in that: The bottom steel plate (9) in step d has a thickness of 6 mm to 10 mm and a width of 160 mm to 220 mm, and the transversely perforated steel member has a thickness of 6 mm to 10 mm and a vertical height of 70 mm to 72 mm.

7. The reinforcement method according to claim 6, characterized in that: The thickness of the longitudinal perforated steel plate (20) in step e is 6 mm to 10 mm, and the vertical height is the same as that of the transverse perforated steel member, that is, 70 mm to 72 mm.

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