A tensioning groove structure at the top of a web beam

Abstract

This utility model relates to a tensioning slot structure at the top of a web beam. Multiple tensioning slots are located at the connection between the upper edge of a prestressed concrete box girder and the top of the web. Multiple longitudinal and transverse truncated steel bars are installed within the top slab of the prestressed concrete box girder. Longitudinal reinforcing bars are placed between the longitudinal truncated steel bars on both sides, and transverse reinforcing bars are placed between the transverse truncated steel bars on both sides. Multiple open stirrups are installed within the web, extending upwards from the top surface of the prestressed concrete box girder. The open stirrups on both sides of the transverse tensioning slots at the top of the web beam are bent in opposite directions to form closed stirrups. This utility model effectively avoids the problem of insufficient tensioning space at the beam ends, has high construction feasibility, and uses a pre-opening and then closing method for the stirrups to compensate for the insufficient shear strength of the cross-section caused by the truncated steel bars due to the tensioning slots at the top of the beam. The structure is simple and construction is highly convenient.

Description

Technical Field

[0001] This utility model relates to the field of bridge construction technology, and in particular to a tensioning groove structure on the top of a web beam. Background Technology

[0002] Prestressed concrete box girders are widely used in modern bridge engineering due to their excellent crack resistance and long span load-bearing capacity.

[0003] For prestressed concrete box girders, when the entire structure is constructed from both sides to the middle, insufficient tensioning space for the prestressed steel strands at the beam ends is likely to occur at the connecting pier locations.

[0004] In the prestressed concrete box girder structure with tensioned beam ends, the transverse steel strands of the beam and the longitudinal steel strands of the web are spatially intersected at the end beam position, which easily leads to collisions and complex local structural stresses, greatly increasing the design difficulty. At the same time, the end beam position bears a large vertical shear force, and combined with the effect of longitudinal and transverse prestressed steel strands, a large number of reinforcing steel bars are required. The dense steel bars and narrow operating space severely restrict the feasibility of construction.

[0005] While using top-tensioning construction can effectively avoid the limitation of insufficient tensioning space at the beam ends, it also presents problems such as severe weakening of the cross-section at the slot location and the severing of a large number of reinforcing bars, which can easily lead to cracks due to insufficient shear strength of the cross-section. Summary of the Invention

[0006] The technical problem to be solved by this utility model is to provide a tensioning groove structure at the top of the web beam, which addresses the shortcomings of the prior art.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A tensioning slot structure at the top of a web beam, applied to a prestressed concrete box girder set at the top of the web, includes multiple tensioning slots at the top of the web beam, which are set at the connection between the upper edge of the prestressed concrete box girder and the top of the web. Within the top plate of the prestressed concrete box girder, corresponding to the web position and located on the outer periphery of the tensioning slots at the top of the web beam, multiple longitudinal cut-off reinforcing bars and multiple transverse cut-off reinforcing bars are respectively arranged longitudinally and transversely. Longitudinal reinforcing bars are arranged between the multiple longitudinal cut-off reinforcing bars on both longitudinal sides, and transverse reinforcing bars are arranged between the multiple transverse cut-off reinforcing bars on both transverse sides. Multiple open stirrups are arranged within the web, extending upwards from the top surface of the prestressed concrete box girder, and distributed on both transverse sides of the tensioning slots at the top of the web beam. The open stirrups on both transverse sides of the tensioning slots at the top of the web beam are bent in opposite directions to form closed stirrups.

[0008] The beneficial effects of this utility model are as follows: The tensioning slot structure at the top of the web beam of this utility model, by setting the tensioning slot at the top of the web beam at the connection between the upper edge of the prestressed concrete box girder and the top of the web, effectively avoids the problem of insufficient tensioning space at the beam end, and has high construction feasibility. At the same time, reinforcing bars are set between the longitudinal and transverse cut-off bars at the upper edge of the prestressed concrete top slab, and the stirrups adopt the construction method of opening first and then closing, which makes up for the problem of insufficient shear strength of the section caused by the cut-off of the reinforcing bars due to the tensioning slot at the top of the beam. The structure is simple and the construction is convenient. While effectively ensuring the structural strength, it can achieve a precise match between the design parameters and the construction results.

[0009] Based on the above technical solution, the present invention can be further improved as follows:

[0010] Furthermore, a sinking groove is provided on the top surface of the prestressed concrete box girder, and the upper edges of the tensioning slots on the top of the web beams are all located within the bottom surface of the sinking groove. Multiple longitudinal cut-off steel bars and multiple transverse cut-off steel bars extend into the sinking groove along the longitudinal and transverse directions, respectively, and the open stirrups extend upward from the bottom surface of the sinking groove.

[0011] The beneficial effect of the above-mentioned further solution is that by setting a sinking groove on the top surface of the prestressed concrete box girder, the longitudinal cut-off steel bars and the transverse cut-off steel bars can be exposed from the top surface of the prestressed concrete box girder, thereby facilitating the connection and reinforcement of the longitudinal cut-off steel bars and the transverse cut-off steel bars on both sides by longitudinal reinforcing steel bars and transverse reinforcing steel bars respectively, ensuring the strength of the overall structure.

[0012] Further: The depth of the sinking trough is 100-140mm.

[0013] Further: Multiple longitudinal cut-off reinforcing bars and multiple transverse cut-off reinforcing bars extend into the sinking trough by 200-400mm along the longitudinal and transverse directions, respectively.

[0014] Furthermore: the tensioning slot at the top of the web beam is a slot with an inverted trapezoidal cross-section, located at the connection between the upper edge of the prestressed concrete box girder and the top of the web.

[0015] The beneficial effects of the above-mentioned further scheme are: by setting a slot with an inverted trapezoidal cross section, on the one hand, it is convenient for the web steel strands to extend into the tensioning slot at the top of the web beam, and on the other hand, it can better avoid the problem of insufficient tensioning space at the beam end.

[0016] Furthermore: the tensioning anchoring end face of the steel strand at the top tensioning slot of the web beam is perpendicular to the center line of the web steel strand, and the side of the slot at the top tensioning slot of the web beam is set parallel to the plane where the web of the prestressed concrete box girder is located.

[0017] The beneficial effects of the above-mentioned further scheme are: by setting the tensioning anchor end face of the steel strand perpendicular to the center line of the web steel strand, a better tensioning effect can be achieved; by setting the side of the slot parallel to the plane where the prestressed concrete box girder web is located, sufficient space can be left to facilitate construction.

[0018] Further: The vertical distance between the inclined surface of the slot on the side away from the tensioning anchor end face of the web beam top tensioning slot and the center line of the web steel strand is 200-400mm, and the vertical distance between the side of the slot and the center line of the web steel strand is 200-400mm.

[0019] Furthermore, the thickness of the web is 0.8-1.2m. Attached Figure Description

[0020] Figure 1 This is a three-dimensional cross-sectional schematic diagram of the tensioning slot at the top of the web beam before tensioning the steel strands, according to an embodiment of the present invention.

[0021] Figure 2 This is a three-dimensional cross-sectional schematic diagram of the tensioning slot at the top of the web beam after tensioning the steel strands, according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the longitudinal section structure of the tensioning groove at the top of the web beam according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of the tensioning groove at the top of the web beam according to an embodiment of the present invention;

[0024] Figure 5 This is a partially enlarged structural diagram of the tensioning groove at the top of the web beam according to an embodiment of the present invention.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] 1. Tensioning slot at the top of the web beam; 2. Web steel strands; 3. Longitudinal cut-off reinforcement; 4. Longitudinal reinforcing reinforcement; 5. Transverse cut-off reinforcement; 6. Transverse reinforcing reinforcement; 7. Open stirrups; 8. Closed stirrups.

[0027] 1-1. Steel strand tensioning and anchoring end face; 1-2. Sloping surface of the groove; 1-3. Side of the groove; 1-4. Top surface of the groove. Detailed Implementation

[0028] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0029] like Figures 1 to 5As shown, a tensioning slot structure at the top of a web beam is applied to a prestressed concrete box girder located at the top of the web. It includes multiple tensioning slots 1 at the top of the web beam, which are located at the connection between the upper edge of the prestressed concrete box girder and the top of the web. Within the top slab of the prestressed concrete box girder, corresponding to the web position and located on the outer periphery of the tensioning slots 1, multiple longitudinal cut-off reinforcing bars 3 and multiple transverse cut-off reinforcing bars 5 are respectively arranged longitudinally and transversely. Longitudinal reinforcing bars 4 are arranged between the longitudinal cut-off reinforcing bars 3 on both sides, and transverse reinforcing bars 6 are arranged between the transverse cut-off reinforcing bars 5 on both sides. Multiple open stirrups 7 are arranged within the web, extending upwards from the top surface of the prestressed concrete box girder. The open stirrups 7 are distributed on both transverse sides of the tensioning slots 1 at the top of the web beam. The open stirrups 7 on both transverse sides of the tensioning slots 1 at the top of the web beam are bent in opposite directions to form closed stirrups 8.

[0030] The tensioning slot structure at the top of the web beam of this utility model effectively avoids the problem of insufficient tensioning space at the beam end by setting the tensioning slot 1 at the connection between the upper edge of the prestressed concrete box girder and the top of the web. It has high construction feasibility. At the same time, reinforcing bars are set between the longitudinal and transverse cut-off bars at the upper edge of the prestressed concrete top slab, and the stirrups adopt the construction method of opening first and then closing. This makes up for the problem of insufficient shear strength of the section caused by the cut-off of the reinforcing bars due to the tensioning slot at the top of the beam. The structure is simple and the construction is convenient. While effectively ensuring the structural strength, it can achieve a precise match between design parameters and construction results.

[0031] In one or more embodiments of this utility model, a sinking groove is provided on the top surface of the prestressed concrete box girder. The upper edges of multiple tensioning slots 1 on the top of the web beams are located within the bottom surface of the sinking groove. Multiple longitudinal cut-off reinforcing bars 3 and multiple transverse cut-off reinforcing bars 5 extend into the sinking groove along the longitudinal and transverse directions, respectively. The open stirrups 7 extend upward from the bottom surface of the sinking groove. By providing a sinking groove on the top surface of the prestressed concrete box girder, the longitudinal cut-off reinforcing bars 3 and transverse cut-off reinforcing bars 5 can be exposed from the top surface of the prestressed concrete box girder. This facilitates the connection and reinforcement of the longitudinal cut-off reinforcing bars 3 and transverse cut-off reinforcing bars 5 on both sides through longitudinal reinforcing bars 4 and transverse reinforcing bars 6, respectively, ensuring the strength of the overall structure.

[0032] In practice, multiple longitudinal cut-off reinforcing bars 3 are welded together on one side by longitudinal reinforcing bars 4, and multiple transverse cut-off reinforcing bars 5 are welded together on one side by transverse reinforcing bars 6.

[0033] In one or more embodiments of this utility model, the depth of the plurality of sinking grooves is 100-140mm. Preferably, in an embodiment of this utility model, the depth of the sinking groove is 120mm.

[0034] In one or more embodiments of this utility model, the plurality of longitudinally cut-off reinforcing bars 3 and the plurality of transversely cut-off reinforcing bars 5 extend into the sinking trough by 200-400mm along the longitudinal and transverse directions, respectively. Preferably, in an embodiment of this utility model, the plurality of longitudinally cut-off reinforcing bars 3 and the plurality of transversely cut-off reinforcing bars 5 extend into the sinking trough by 300mm along the longitudinal and transverse directions, respectively.

[0035] In one or more embodiments of this utility model, the tensioning slot 1 at the top of the web beam is a slot with an inverted trapezoidal cross-section, located at the connection between the upper edge of the prestressed concrete box girder and the top of the web. By setting the slot with an inverted trapezoidal cross-section, on the one hand, it is convenient for the web steel strands 2 to extend into the tensioning slot 1 at the top of the web beam, and on the other hand, it can better avoid the problem of insufficient tensioning space at the beam end.

[0036] In one or more embodiments of this utility model, the tensioning anchorage end face 1-1 of the steel strand at the top tensioning slot 1 of the web beam is perpendicular to the centerline of the web steel strand 2, and the side surface 1-3 of the slot 1 is parallel to the plane of the prestressed concrete box girder web. By setting the tensioning anchorage end face 1-1 of the steel strand perpendicular to the centerline of the web steel strand 2, a better tensioning effect can be achieved. By setting the side surface 1-3 of the slot parallel to the plane of the prestressed concrete box girder web, sufficient space can be left to facilitate construction.

[0037] In one or more embodiments of this utility model, the vertical distance between the inclined surface 1-2 of the slot on the side away from the tensioning anchor face 1-1 of the web beam top tensioning slot 1 and the centerline of the web steel strand 2 is 200-400mm, and the vertical distance between the side surface 1-3 of the slot and the centerline of the web steel strand 2 is 200-400mm. Preferably, in an embodiment of this utility model, the vertical distance between the inclined surface 1-2 of the slot and the centerline of the web steel strand 2 is 300mm, and the vertical distance between the side surface 1-3 of the slot and the centerline of the web steel strand 2 is 300mm.

[0038] Here, the depth of the sinking groove is the height difference between the top surface of the prestressed concrete box girder and the top surface 1-4 of the tensioning groove 1 on the top of the web beam, which is preferably 120mm in this invention.

[0039] In one or more embodiments of this utility model, the thickness of the web is 0.8-1.2 μm. Preferably, in an embodiment of this utility model, the thickness of the web is increased to 1.0 μm.

[0040] The construction process of the tensioning groove structure at the top of the web beam of this utility model is as follows:

[0041] Step a: The "inverted trapezoidal" groove uses ordinary wooden formwork. The upper edge of the groove and the outer recessed groove (widened area) use rigid polyethylene foam board as the concrete top surface formwork. When installing the formwork, the longitudinal cut-off steel bar 3 and the transverse cut-off steel bar 5 should pass through the rigid polyethylene foam board. The groove is formed by pouring concrete.

[0042] Step b: Remove the formwork;

[0043] Step c: Insert the web steel strand 2 into the corrugated pipe of the web and tension the longitudinal prestressed steel strand of the web. After the web steel strand is tensioned, insert the transverse steel strand into the corrugated pipe of the top plate of the prestressed concrete box girder and tension the transverse prestressed steel strand of the top plate.

[0044] Step d: Use single-sided welding to connect the longitudinal cut-off steel bars 3 and the longitudinal reinforcing steel bars 4 within the sinkhole area;

[0045] Here, the longitudinal steel bars at the top edge of the prestressed concrete box girder are first cut off, and then longitudinal reinforcing steel bars 4 are welded between the cut longitudinal steel bars 3 to restore and strengthen the steel bars.

[0046] Step e: Bend the open stirrup 7 to form the closed stirrup 8;

[0047] Step f: Use single-sided welding to connect the transverse cut-off steel bars 5 and transverse reinforcing steel bars 6 within the sinkhole area;

[0048] Here, the transverse steel bars at the top edge of the prestressed concrete box girder are first cut off, and then transverse reinforcing steel bars 6 are welded between the cut transverse steel bars 5 to restore and strengthen the steel bars.

[0049] Step g: Pour the anchoring concrete at the top tensioning slot of the web beam.

[0050] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A tensioning slot structure at the top of a web beam, applied to a prestressed concrete box girder set at the top of the web, characterized in that: The prestressed concrete box girder includes multiple tensioning slots (1) on the top of the web beam. These slots (1) are located at the connection between the upper edge of the prestressed concrete box girder and the top of the web. The top of the prestressed concrete box girder has multiple longitudinal cut-off steel bars (3) and multiple transverse cut-off steel bars (5) arranged longitudinally and transversely on the outer periphery of the tensioning slots (1) on the top of the web beam, corresponding to the web position. Longitudinal reinforcing bars (4) are arranged between the longitudinal cut-off steel bars (3) on both sides, and transverse reinforcing bars (6) are arranged between the transverse cut-off steel bars (5) on both sides. Multiple open stirrups (7) are arranged in the web. The open stirrups (7) extend upwards from the top surface of the prestressed concrete box girder and are distributed on both transverse sides of the tensioning slots (1) on the top of the web beam. The open stirrups (7) on both transverse sides of the tensioning slots (1) on the top of the web beam are bent in opposite directions to form closed stirrups (8).

2. The tensioning slot structure at the top of the web beam according to claim 1, characterized in that: The top surface of the prestressed concrete box girder is provided with a sinking groove. The upper edges of the multiple tensioning slots (1) on the top of the web beam are located inside the bottom surface of the sinking groove. Multiple longitudinal cut-off steel bars (3) and multiple transverse cut-off steel bars (5) extend into the sinking groove along the longitudinal and transverse directions, respectively. The open stirrups (7) extend upward from the bottom surface of the sinking groove.

3. The tensioning groove structure at the top of the web beam according to claim 2, characterized in that: The depth of the sinking trough is 100-140mm.

4. The tensioning slot structure at the top of the web beam according to claim 2, characterized in that: Multiple longitudinal cut-off reinforcing bars (3) and multiple transverse cut-off reinforcing bars (5) extend into the sinking trough 200-400mm along the longitudinal and transverse directions, respectively.

5. The tensioning slot structure at the top of the web beam according to claim 1, characterized in that: The tensioning slot (1) on the top of the web beam is a slot with an inverted trapezoidal cross section, which is set at the connection between the upper edge of the prestressed concrete box girder and the top of the web.

6. The tensioning slot structure at the top of the web beam according to claim 5, characterized in that: The tensioning anchoring end face (1-1) of the steel strand of the tensioning slot (1) at the top of the web beam is perpendicular to the center line of the web steel strand (2), and the side of the slot (1-3) of the tensioning slot (1) at the top of the web beam is set parallel to the plane of the prestressed concrete box girder web.

7. The tensioning slot structure at the top of the web beam according to claim 6, characterized in that: The vertical distance between the inclined surface (1-2) of the slot (1) on the side away from the tension anchor end face (1-1) of the web beam and the center line of the web steel strand (2) is 200-400mm, and the vertical distance between the side surface (1-3) of the slot and the center line of the web steel strand (2) is 200-400mm.

8. The tensioning slot structure at the top of the web beam according to any one of claims 1-7, characterized in that: The thickness of the web is 0.8-1.2m.

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