A semi-open grid rear plate steel-concrete composite section

Abstract

This invention discloses a semi-open grid-type steel-concrete composite section, comprising a steel-concrete composite zone, an outer steel plate of the composite section, a longitudinally aligned steel grid force-transmitting partition plate on the inner side of the outer steel plate, and a transversely aligned rear bearing steel plate on the inner side of the outer steel plate. Inner grid plates are located at the ends of the force-transmitting partition plate and the rear bearing steel plate. The outer steel plate, the force-transmitting partition plate, the rear bearing steel plate, and the inner grid plates enclose a steel grid, which is filled with concrete. This invention significantly shortens the length of the enclosed grid section of the composite section, resulting in a simpler overall layout. The increased open space and the inclined arrangement of the inner grid plates facilitate construction operations. The significantly reduced length of the composite section compared to the front and rear plate types avoids excessive local rigidity in the main beam, resulting in more uniform stress and deformation of the main beam. The inclined arrangement of the inner grid plates promotes dense concrete pouring, ensuring project quality.

Description

Technical Field

[0001] This invention belongs to the technical field of bridge joint sections, specifically relating to a semi-open grid rear plate type steel-concrete joint section. Background Technology

[0002] Currently, the commonly used joint section forms for hybrid main beams of highway and railway bridges are prestressed post-slab or prestressed front and rear slabs.

[0003] The prestressed slab joint section typically uses a rear bearing plate and a steel grating with a single-sided opening along the direction of the concrete beam to transfer force. The bottom plate of the grating at the upper edge of the main beam or the top plate of the grating at the lower edge is set horizontally. When pouring concrete, corner gaps are likely to exist, which increases the amount of construction inspection and grouting work. Moreover, the horizontally set plate is inconvenient for workers to carry out construction welding and reinforcement placement operations. The transverse diaphragm in the joint zone is set at the side end of the concrete beam, which cannot fully play the role of circumferential support for the joint section.

[0004] The prestressed slab section typically uses front and rear bearing plates and front and rear steel gratings to transfer force. The front grating is usually open, but the grating between the front and rear bearing plates relies on the structural holes on the top plate of the grating and the front bearing plate for concrete pouring. This type of section is long, complex in structure, and has high local rigidity of the main beam. In addition, the steel grating is narrow, making on-site construction difficult and the quality of the project hard to guarantee. Summary of the Invention

[0005] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a semi-open grid rear plate steel-concrete composite section.

[0006] The technical solution of the present invention is: a semi-open grid-type steel-concrete composite section, comprising a steel-concrete composite area anchored to a concrete box girder, wherein the steel-concrete composite area comprises a composite section outer steel plate anchored to each plate of the outer contour of the concrete box girder, wherein a steel grid force transmission partition plate is provided on the inner side of the composite section outer steel plate in the longitudinal direction and located in the middle, and a rear bearing steel plate in the transverse direction is also provided on the inner side of the composite section outer steel plate, wherein inner side plates of the grid are provided at the ends of the steel grid force transmission partition plate and the rear bearing steel plate, and the composite section outer steel plate, the steel grid force transmission partition plate, the rear bearing steel plate, and the inner side plates of the grid are arranged to form a plurality of steel grids distributed along the periphery of the box girder, wherein high rheological self-compacting steel fiber concrete is poured in the steel grids.

[0007] Furthermore, a concrete diaphragm is provided on the inner side of the outer steel plate of the connecting section.

[0008] Furthermore, the outer steel plate of the connecting section is also equipped with web plate force transmission components and side web plate force transmission components, both of which are arranged along the bridge direction.

[0009] Furthermore, the web force transmission component includes a steel grid chamber force transmission partition plate fixed to the outer steel plate of the connecting section. There are two steel grid chamber force transmission partition plates, and a middle web force transmission steel plate is arranged between the two steel grid chamber force transmission partition plates. The middle web force transmission steel plate and the steel grid chamber force transmission partition plate are an integral structure.

[0010] Furthermore, the side web plate force transmission component includes a steel grid chamber force transmission partition plate fixed to the outer steel plate of the connecting section. There are two steel grid chamber force transmission partition plates, and a side web plate force transmission steel plate is arranged between the two steel grid chamber force transmission partition plates. The side web plate force transmission steel plate and the steel grid chamber force transmission partition plate are an integral structure.

[0011] Furthermore, the top mounting end of the steel grating force transmission partition is inclined, the inner side plate of the grating is set on the top mounting end, and the horizontal angle between the inner side plate of the grating and the horizontal plane is 5~10° downward.

[0012] Furthermore, the steel grating includes an upper edge steel grating located on the lower side of the outer steel plate at the top of the connecting section and a lower edge steel grating located on the upper side of the outer steel plate at the bottom of the connecting section, and each steel grating includes an inclined surface composed of inner side plates of the grating.

[0013] Furthermore, the rear bearing steel plate forms a steel strand anchorage node on the side facing the steel box girder, and the prestressed steel strands in the concrete beam pass through the rear bearing steel plate and are anchored in the steel strand anchorage node.

[0014] Furthermore, the upper edge steel grating chamber is provided with grouting holes and venting holes. The grouting holes are located in the outer steel plate of the joint section, and the venting holes are located at the joint between the outer steel plate of the joint section and the rear bearing steel plate.

[0015] Furthermore, the lower edge steel grating chamber is provided with grouting holes and venting holes. The grouting holes are located in the inner side plate of the grating chamber, and the venting holes are located at the junction of the inner side plate of the grating chamber and the rear bearing steel plate.

[0016] This invention significantly shortens the length of the enclosed section of the combined compartment, resulting in a simpler overall layout, increased open space, and an inclined arrangement of the inner side panels of the compartment, which is beneficial for workers' construction operations. The length of the combined section is significantly reduced compared to the front and rear panel types, avoiding excessive local rigidity of the main beam and making the stress and deformation of the main beam more uniform. The inclined arrangement of the inner side panels of the compartment is conducive to the compaction of concrete pouring and ensures the quality of the project. The transverse diaphragm in the middle of the combined section provides ring support, which is beneficial to the overall lateral stability of the combined section.

[0017] This invention shortens the joint length and simplifies the construction of the steel-concrete joint section while ensuring structural safety and smooth force transmission, thus saving steel. At the same time, it facilitates rapid on-site construction and saves construction time. Attached Figure Description

[0018] Figure 1Elevation layout along the bridge at the center of this invention;

[0019] Figure 2 Elevation view of the web plate along the bridge direction in this invention;

[0020] Figure 3 Elevation view of the side web plate of this invention along the bridge direction;

[0021] Figure 4 The present invention provides a plan view of the bridge's 1 / 2 plan layout at the 1 / 2 beam height along the bridge direction.

[0022] Figure 5 Figure 1 Cross-sectional view of surface 1-1;

[0023] Figure 6 Figure 1 Cross-sectional view of surface 2-2;

[0024] Figure 7 Figure 1 Cross-sectional view of surface 3-3;

[0025] Figure 8 Figure 1 Cross-sectional view of plane 4-4;

[0026] in:

[0027] 1. Steel beam stiffness transition zone; 2. Steel-concrete composite zone

[0028] 1-1 Steel plate surrounding the steel beam 1-2 Stiffening ribs on the steel plate surrounding the steel beam

[0029] 1-3 Middle web of steel beam 1-4 Side web of steel beam

[0030] 1-5 Variable height section T-steel; 1-6 Intermediate transverse diaphragm.

[0031] 1-7 Annular diaphragm

[0032] 2-1 Steel plate around the joint section

[0033] 2-2 Rear bearing steel plate 2-3 Middle web force transmission steel plate

[0034] 2-4 Side web plate for force transmission; 2-5 Steel grating partition for force transmission.

[0035] 2-6 Air nozzle steel grating force transmission plate; 2-7 Inner side plate of grating.

[0036] 2-8 Side steel plate of web joint area 2-9 Inner steel plate of nozzle joint area

[0037] 2-10 Steel baffle on the outer side of the diaphragm 2-11 Cylindrical head stud

[0038] 2-12 PBL key insertion reinforcement 2-13 Concrete diaphragm

[0039] 2-14 Vent hole 2-15 Prestressed steel strand. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0041] like Figures 1-8 As shown, a semi-open grid-type steel-concrete composite section includes a steel-concrete composite area 2 fixed to a concrete box girder. The steel-concrete composite area 2 includes a composite section outer steel plate 2-1 anchored to each plate of the outer contour of the concrete box girder. A steel grid force transmission partition 2-5 is provided on the inner side of the composite section outer steel plate 2-1 in the longitudinal direction and located in the middle. A rear bearing steel plate 2-2 in the transverse direction is also provided on the inner side of the composite section outer steel plate 2-1. The ends of the steel grid force transmission partition 2-5 and the rear bearing steel plate 2-2 are provided with grid inner side plates 2-7. The composite section outer steel plate 2-1, steel grid force transmission partition 2-5, rear bearing steel plate 2-2, and grid inner side plates 2-7 enclose and form multiple steel grids distributed along the periphery of the box girder. High rheological self-compacting steel fiber concrete is poured into the steel grids.

[0042] A concrete diaphragm 2-13 is provided on the inner side of the outer steel plate 2-1 of the connecting section.

[0043] The outer steel plate 2-1 of the connecting section is also provided with web plate force transmission components and side web plate force transmission components, both of which are arranged along the bridge direction.

[0044] The web force transmission component includes a steel grid chamber force transmission partition 2-5 fixed to the outer steel plate 2-1 of the connecting section. There are two steel grid chamber force transmission partitions 2-5, and a middle web force transmission steel plate 2-3 is arranged between the two steel grid chamber force transmission partitions 2-5. The middle web force transmission steel plate 2-3 and the steel grid chamber force transmission partition 2-5 are an integral structure.

[0045] The side web plate force transmission component includes a steel grid chamber force transmission partition 2-5 fixed to the outer steel plate 2-1 of the connecting section. There are two steel grid chamber force transmission partitions 2-5, and a side web plate force transmission steel plate 2-4 is arranged between the two steel grid chamber force transmission partitions 2-5. The side web plate force transmission steel plate 2-4 and the steel grid chamber force transmission partition 2-5 are an integral structure.

[0046] The top mounting end of the steel grating force transmission partition 2-5 is inclined, and the inner side plate 2-7 of the grating is set on the top mounting end. The horizontal angle between the inner side plate 2-7 of the grating and the horizontal plane is 5~10° downward.

[0047] The steel grating includes an upper edge steel grating located below the outer steel plate 2-1 at the top of the connecting section and a lower edge steel grating located above the outer steel plate 2-1 at the bottom of the connecting section. Each steel grating includes an inclined surface composed of inner side plates 2-7.

[0048] The rear bearing steel plate 2-2 forms a steel strand anchorage node on the side facing the steel box girder, and the prestressed steel strands 2-15 in the concrete beam pass through the rear bearing steel plate 2-2 and are anchored in the steel strand anchorage node.

[0049] The upper edge steel grating chamber is provided with grouting holes and venting holes 2-14. The grouting holes are located in the outer steel plate 2-1 of the joint section, and the venting holes are located at the joint of the outer steel plate 2-1 of the joint section and the rear bearing steel plate 2-2.

[0050] The lower edge steel grating is provided with grouting holes and venting holes 2-14. The grouting holes are located in the inner side plate 2-7 of the grating, and the venting holes are located at the junction of the inner side plate 2-7 of the grating and the rear bearing steel plate 2-2.

[0051] Two trapezoidal holes are formed in the steel grating force transmission partition 2-5, and the hypotenuse of the trapezoidal holes corresponds to the inclined surface of the steel grating force transmission partition 2-5.

[0052] The steel grating force transmission partitions 2-5 also have reinforcing bar holes. This allows the transverse bridge to become a unified whole through the reinforcing bars.

[0053] like Figure 7 As shown, the outer steel plate 2-1 at the top of the connecting section and the outer steel plate 2-1 at the bottom of the connecting section are connected and bent at their ends. The outer steel plate 2-1 of the connecting section is closed with the force transmission partition plate 2-5 of the steel grid chamber. In its closed space, there is a wind nozzle steel grid chamber force transmission plate 2-6 connected to the outer steel plate 2-1 of the connecting section. The free end of the wind nozzle steel grid chamber force transmission plate 2-6 is provided with a wind nozzle connecting area inner steel plate 2-9.

[0054] The outer steel plate 2-1 of the connecting section, the force-transmitting steel plate 2-4 of the side web of the steel grid chamber, and the inner steel plate 2-9 of the air nozzle connecting area are used to form the air nozzle steel grid chamber.

[0055] Parallel side steel plates 2-8 for web joint area are provided on both sides of the web force transmission steel plate 2-3, and the side steel plates 2-8 for web joint area are surrounded by the inner side plate 2-7 of the compartment.

[0056] Parallel side plates 2-8 are provided on both sides of the side web force transmission steel plate 2-4, and the side plates 2-8 of the web joint area are surrounded by the inner side plate 2-7 of the compartment.

[0057] Accordingly, a steel strand passage hole is provided between the side steel plate 2-8 of the web joint area and the middle web force transmission steel plate 2-3 or the side web force transmission steel plate 2-4, and the prestressed steel strand 2-15 passes through the above passage hole and is anchored to the rear bearing steel plate 2-2.

[0058] One side of the steel-concrete composite zone 2 is anchored to the concrete box girder, and the other side of the steel-concrete composite zone 2 is connected to the steel beam stiffness transition zone 1, which is connected to the steel box girder.

[0059] The outer steel plate 2-1 and the inner side plate 2-7 of the steel-concrete composite zone 2 are extended outward along the bridge and then welded and fixed to the components in the steel beam stiffness transition zone 1.

[0060] The steel beam stiffness transition zone 1 includes a steel plate 1-1 on the outer perimeter of the steel beam. The steel plate 1-1 on the outer perimeter of the steel beam is arranged in the same manner as the steel plate 2-1 on the outer perimeter of the connecting section. The steel plate 1-1 on the outer perimeter of the steel beam and the steel plate 2-1 on the outer perimeter of the connecting section are fixed by welding.

[0061] A variable height section T-steel 1-5 is provided on the inner side of the outer steel plate 1-1 of the steel beam. The inclination angle of the flange plate of the variable height section T-steel 1-5 is consistent with the inclination angle of the inner side plate 2-7 of the grid. The variable height section T-steel 1-5 and the inner side plate 2-7 of the grid are welded to both sides of the rear bearing steel plate 2-2.

[0062] Correspondingly, a central web plate 1-3 and a side web plate 1-4 are also provided in the outer steel plate 1-1 of the steel beam. The central web plate 1-3 and the side web plate 1-4 of the steel beam are both steel structural plates.

[0063] Correspondingly, the position of the web plate 1-3 in the steel beam corresponds to the position of the load-bearing steel plate 2-3 in the web plate of the steel-concrete composite zone 2. Similarly, the position of the side web plate 1-4 in the steel beam corresponds to the position of the load-bearing steel plate 2-4 in the side web plate of the steel-concrete composite zone 2.

[0064] The steel beam stiffness transition zone 1 is also provided with intermediate transverse diaphragms 1-6 and annular transverse diaphragms 1-7. The intermediate transverse diaphragms 1-6 and annular transverse diaphragms 1-7 are parallel to each other, and the intermediate transverse diaphragms 1-6 are close to the steel-concrete composite zone 2.

[0065] Preferably, the force transmission member of the middle web plate protrudes from the concrete diaphragm 2-13, and the middle web plate 1-3 of the steel beam and the force transmission steel plate 2-3 of the middle web plate are respectively welded to both sides of the rear bearing steel plate 2-2. The force transmission steel plate 2-3 of the middle web plate is provided with PBL key inserting steel bar 2-12, thereby realizing a firm connection between the middle web plate 1-3 of the steel beam and the middle web plate of the concrete box girder.

[0066] Preferably, the side web force transmission member protrudes from the concrete diaphragm 2-13, and the steel beam side web 1-4 and the side web force transmission steel plate 2-4 are respectively welded to both sides of the rear bearing steel plate 2-2. The side web force transmission steel plate 2-4 is provided with PBL key inserting steel bar 2-12, thereby realizing a firm connection between the steel beam side web 1-4 and the concrete box girder side web.

[0067] Furthermore, an outer steel baffle 2-10 is provided on the outer wall of the concrete diaphragm 2-13. The outer steel baffle 2-10 connects to the steel components perpendicular to it. For example, the outer steel baffle 2-10 connects the two side steel plates 2-8 of the web joint area into a whole, or the outer steel baffle 2-10 connects the side steel plates 2-8 of the web joint area and the inner steel plate 2-9 of the air nozzle joint area into a whole.

[0068] Correspondingly, in the grouting process of the steel-concrete composite zone 2, steel fiber high-rheological self-compacting concrete is grouted.

[0069] The inner surfaces of the outer steel plate 2-1 of the main beam, the rear bearing steel plate 2-2, the inner side plate of the compartment 2-7, the side steel plate of the web joint area 2-8, the inner side steel plate of the air nozzle joint area 2-9, and the outer steel baffle of the transverse diaphragm 2-10 are all provided with cylindrical head weld studs 2-11 for connection and anchoring.

[0070] The middle web force-transmitting steel plate 2-3, the side web force-transmitting steel plate 2-4, the steel grid chamber force-transmitting partition 2-5, and the air nozzle steel grid chamber force-transmitting plate 2-6 are provided with openings, and the PBL key is formed after the reinforcing bar 2-12 passes through.

[0071] The construction process of this invention is as follows:

[0072] Step 1: Install each component in the following order: outer steel plate 1-1 of the steel beam, outer steel plate 2-1 of the joint section, rear bearing steel plate 2-2, middle web plate and stiffening ribs 1-3 of the steel beam, side web plate and stiffening ribs 1-4 of the steel beam, outer steel plate stiffening ribs 1-2 of the steel beam, variable height section T-steel 1-5, middle web plate force transmission steel plate 2-3, side web plate force transmission steel plate 2-4, steel grating force transmission partition 2-5, air nozzle steel grating force transmission plate 2-6, inner side plate of the grating 2-7, side steel plate of the web joint area 2-8, inner side steel plate of the air nozzle joint area 2-9, and outer steel baffle of the transverse diaphragm 2-10.

[0073] Among them, before installing the outer steel plate 2-1 of the connecting section, the rear bearing steel plate 2-2, the inner side plate of the grid 2-7, the side steel plate of the web plate connecting area 2-8, the inner side steel plate of the air nozzle connecting area 2-9, and the outer steel baffle of the transverse diaphragm 2-10, the cylindrical head welding studs 2-11 should be welded to the corresponding positions of the steel plates.

[0074] Step 2: Transport and hoist the above-mentioned installation components to the designed location.

[0075] Step 3: Install and position the PBL key, insert the reinforcing bars 2-12, and the ordinary reinforcing bars and prestressed steel strands in the steel-concrete composite section;

[0076] Step 4: Set up the template and pour the large rheological steel fiber self-compacting concrete in the order of bottom plate, web plate, diaphragm plate and top plate, and then cure it.

[0077] Step 5: After the concrete strength of the bonding section reaches the design requirements, complete the longitudinal prestressed steel strand tensioning of the top plate, bottom plate, and web of the main beam by 2-15.

[0078] This invention significantly shortens the length of the enclosed section of the combined compartment, resulting in a simpler overall layout, increased open space, and an inclined arrangement of the inner side panels of the compartment, which is beneficial for workers' construction operations. The length of the combined section is significantly reduced compared to the front and rear panel types, avoiding excessive local rigidity of the main beam and making the stress and deformation of the main beam more uniform. The inclined arrangement of the inner side panels of the compartment is conducive to the compaction of concrete pouring and ensures the quality of the project. The transverse diaphragm in the middle of the combined section provides ring support, which is beneficial to the overall lateral stability of the combined section.

[0079] This invention shortens the joint length and simplifies the construction of the steel-concrete joint section while ensuring structural safety and smooth force transmission, thus saving steel. At the same time, it facilitates rapid on-site construction and saves construction time.

Claims

1. A semi-open grid-type steel-concrete composite section, comprising a steel-concrete composite zone (2) anchored to a concrete box girder, characterized in that: The steel-concrete composite zone (2) includes a composite section outer steel plate (2-1) anchored to each plate of the outer contour of the concrete box girder. A steel grid cell force transmission partition (2-5) is provided on the inner side of the composite section outer steel plate (2-1) in the longitudinal direction and located in the middle. A transverse rear bearing steel plate (2-2) is also provided on the inner side of the composite section outer steel plate (2-1). The ends of the steel grid cell force transmission partition (2-5) and the rear bearing steel plate (2-2) are provided with grid inner side plates (2-7). The composite section outer steel plate (2-1), the steel grid cell force transmission partition (2-5), the rear bearing steel plate (2-2), and the grid inner side plates (2-7) enclose and form multiple steel grid cells distributed along the periphery of the box girder. Large rheological self-compacting steel fiber concrete is poured in the steel grid cells. The top mounting end of the steel grating force transmission partition (2-5) is inclined, and the inner side plate (2-7) of the grating is set on the top mounting end. The horizontal angle between the inner side plate (2-7) of the grating and the horizontal plane is 5~10°. The outer steel plate (2-1) of the connecting section is also provided with web plate force transmission components and side web plate force transmission components, both of which are arranged along the bridge direction; The force transmission member of the middle web plate protrudes from the concrete diaphragm (2-13). The middle web plate (1-3) of the steel beam and the force transmission steel plate (2-3) of the middle web plate are respectively welded to both sides of the rear bearing steel plate (2-2). The force transmission steel plate (2-3) of the middle web plate is provided with PBL key inserted steel bar (2-12), thereby realizing a firm connection between the middle web plate (1-3) of the steel beam and the middle web plate of the concrete box girder. The side web force transmission member protrudes from the concrete diaphragm (2-13). The steel beam side web (1-4) and the side web force transmission steel plate (2-4) are respectively welded to both sides of the rear bearing steel plate (2-2). The side web force transmission steel plate (2-4) is provided with PBL key inserted steel bar (2-12), thereby realizing a firm connection between the steel beam side web (1-4) and the concrete box girder side web. The outer wall of the concrete diaphragm (2-13) is provided with an outer steel baffle (2-10), which is connected to a steel component perpendicular to it. The outer steel plate (2-1) at the top of the connecting section and the outer steel plate (2-1) at the bottom of the connecting section are bent and connected at their ends. The outer steel plate (2-1) of the connecting section is closed with the force transmission partition plate (2-5) of the steel grid chamber. In its closed space, a wind nozzle steel grid chamber force transmission plate (2-6) connected to the outer steel plate (2-1) of the connecting section is provided. The free end of the wind nozzle steel grid chamber force transmission plate (2-6) is provided with a steel plate (2-9) inside the wind nozzle connecting area. The outer steel plate (2-1) of the connecting section, the force-transmitting steel plate (2-4) of the side web plate of the steel grid chamber, and the inner steel plate (2-9) of the air nozzle connecting area are used to enclose and form the air nozzle steel grid chamber; The steel beam stiffness transition zone (1) includes a steel beam outer steel plate (1-1), which is arranged in the same manner as the outer steel plate (2-1) of the connecting section. A variable height section T-steel (1-5) is provided on the inner side of the steel beam outer steel plate (1-1). The inclination angle of the flange plate of the variable height section T-steel (1-5) is consistent with the inclination angle of the inner side plate (2-7) of the grid. The variable height section T-steel (1-5) and the inner side plate (2-7) of the grid are welded to both sides of the rear bearing steel plate (2-2).

2. The semi-open grid rear plate steel-concrete composite section according to claim 1, characterized in that: A concrete diaphragm (2-13) is provided on the inner side of the outer steel plate (2-1) of the connecting section.

3. The semi-open grid rear plate steel-concrete composite section according to claim 2, characterized in that: The web force transmission component includes a steel grid chamber force transmission partition (2-5) fixed to the outer steel plate (2-1) of the connecting section. There are two steel grid chamber force transmission partitions (2-5), and a middle web force transmission steel plate (2-3) is provided between the two steel grid chamber force transmission partitions (2-5). The middle web force transmission steel plate (2-3) and the steel grid chamber force transmission partition (2-5) are an integral structure.

4. The semi-open grid rear plate steel-concrete composite section according to claim 1, characterized in that: The side web plate force transmission component includes a steel grid chamber force transmission partition (2-5) fixed to the outer steel plate (2-1) of the connecting section. There are two steel grid chamber force transmission partitions (2-5), and a side web plate force transmission steel plate (2-4) is provided between the two steel grid chamber force transmission partitions (2-5). The side web plate force transmission steel plate (2-4) and the steel grid chamber force transmission partition (2-5) are an integral structure.

5. The semi-open grid rear plate steel-concrete composite section according to claim 1, characterized in that: The steel grating includes an upper edge steel grating located below the top outer steel plate (2-1) of the connecting section and a lower edge steel grating located above the bottom outer steel plate (2-1) of the connecting section. Each steel grating includes an inclined surface composed of an inner side plate (2-7).

6. The semi-open grid rear plate steel-concrete composite section according to claim 5, characterized in that: The rear bearing steel plate (2-2) forms a steel strand anchorage node on the side facing the steel box girder, and the prestressed steel strands (2-15) in the concrete beam pass through the rear bearing steel plate (2-2) and are anchored in the steel strand anchorage node.

7. A semi-open grid rear plate steel-concrete composite section according to claim 5, characterized in that: The upper edge steel grating chamber is provided with grouting holes and venting holes (2-14). The grouting holes are located in the outer steel plate (2-1) of the joint section, and the venting holes are located at the joint of the outer steel plate (2-1) of the joint section and the rear bearing steel plate (2-2).

8. The semi-open grid rear plate steel-concrete composite section according to claim 5, characterized in that: The lower edge steel grating is provided with grouting holes and venting holes (2-14). The grouting holes are located in the inner side plate (2-7) of the grating, and the venting holes are located at the junction of the inner side plate (2-7) of the grating and the rear bearing steel plate (2-2).

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