A steel box girder splicing structure for expressway reconstruction and expansion

Abstract

This utility model discloses a steel box girder splicing structure for highway reconstruction and expansion, including a newly widened steel box girder bridge, an old widened steel box girder bridge, a top plate connection assembly, and a transverse diaphragm connection assembly. The top plates of the newly widened and old widened steel box girder bridges are fixedly connected by welding, and a top plate connection assembly is provided on the top surface of both top plates. No connection structure is provided between the bottom plates. Transverse diaphragm connection assemblies are provided at the transverse diaphragms of the newly widened and old widened steel box girder bridges. This invention effectively improves the connection strength and integrity of the tops of the new and old widened steel box girder bridges through the top plate connection assembly, enhances the load-bearing capacity of the structure under vehicle loads, and ensures driving safety. The transverse diaphragm connection assembly optimizes the lateral force transmission performance between the new and old steel box girder bridges, making the structure more uniformly stressed and reducing local stress concentration.

Description

Technical Field

[0001] This utility model belongs to the field of bridge construction technology, and more specifically, relates to a steel box girder splicing structure for highway reconstruction and expansion. Background Technology

[0002] With the continuous development of my country's expressways, the country's highway network has been constantly improved. However, it is undeniable that some of the existing expressways are no longer able to meet the demands of the ever-increasing traffic volume in terms of operating conditions and service quality. Therefore, the upgrading and expansion of expressways is imperative.

[0003] With economic development and increased traffic flow, many highways need to be upgraded and expanded to improve their capacity. Steel box girders, as an important bridge structure, are widely used in upgrade and expansion projects due to their advantages such as light weight, high strength, and fast construction speed. In highway upgrades and expansions, the most common bridge widening methods are widening on both sides and separate construction. However, when upgrading existing highways, it is inevitable to encounter situations where they cross navigable rivers. With the continuous development of water transport, many existing bridges were built relatively early and have small spans, which can no longer meet the current navigation clearance requirements for inland waterways. In this case, if the upgrade is done by widening on both sides, the expanded bridge will have the same span as the original bridge, and the upgraded bridge will not meet navigation requirements. If separate construction is carried out, the route will deviate from the original alignment, reducing the utilization rate of the original highway and causing some waste. In this situation, if demolition and reconstruction are adopted, a phased construction scheme is usually used when building new steel box girder bridges to meet traffic flow requirements. Specifically, the project first involves constructing a section of the old bridge on its outer side as a temporary access road to ensure normal traffic flow. Subsequently, the old bridge is demolished, and another section of the steel box girder bridge is built on the same site. This phased construction process presents a challenge: the connection between the earlier and later sections must be carefully designed. A reliable splicing structure is needed to ensure the precision and overall stability of the connection between the old and new bridge sections, while also guaranteeing safety and efficiency during construction. Utility Model Content

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this utility model provides a steel box girder splicing structure for highway reconstruction and expansion. In the connection structure, the top plates of the new and old widened steel box girder bridges are welded together to ensure the continuity and integrity of the top plates. The transverse diaphragms are connected to the bridge top plates with high-strength bolts via connecting plates, strengthening the overall transverse connection and promoting the formation of a synergistic force-bearing whole after the widening of the steel box girder, achieving uniform force transmission and significantly improving structural stability and load-bearing capacity. Through the PBL shear key penetrating the reinforcing bars, the new and old steel box girder bridge top plates are tightly connected, forming a strong mechanical embedding force to ensure... Under complex conditions such as vehicle loads and temperature changes, the new and old steel box girders share the load and deform together, avoiding localized damage caused by uneven stress. The PBL shear keys work synergistically with the top plate welding, stirrups, and other structures to fully utilize the bending and shear mechanical properties, distribute and transfer the load, reduce stress concentration, further enhance the overall load-bearing capacity and stability of the bridge, and extend its service life. The UHPC concrete installed at the splicing location enhances the local stiffness of the steel bridge deck splicing area, reduces deformation under repeated vehicle loads, reduces fatigue stress amplitude, eliminates the risk of cracking, and improves fatigue resistance.

[0005] To achieve the above objectives, this utility model proposes a steel box girder splicing structure for highway reconstruction and expansion, including a newly widened steel box girder bridge, an old widened steel box girder bridge, a top plate connection assembly, and a transverse diaphragm connection assembly. The top plates of the newly widened steel box girder bridge and the old widened steel box girder bridge are fixedly connected by welding, and a top plate connection assembly is provided on the top surface of the two top plates. No connection structure is provided between the bottom plates, which can effectively improve the connection strength and integrity of the top of the new and old widened steel box girder bridges, enhance the load-bearing capacity of the structure under vehicle loads, and ensure driving safety. The new and old widened steel box girder bridges are equipped with diaphragm connection components at their transverse diaphragms to optimize the lateral force transmission performance between the new and old steel box girder bridges, making the structure more uniformly stressed and reducing local stress concentration.

[0006] Furthermore, the top plate connection assembly includes a plurality of first PBL shear keys and a plurality of second PBL shear keys. The plurality of first PBL shear keys are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the newly widened steel box girder bridge near the splice joint, and the second PBL shear keys are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the old widened steel box girder bridge near the splice joint.

[0007] Furthermore, both the first PBL shear key and the second PBL shear key are made of steel plate, which is 98cm long, 9cm high and 2cm thick, and both the first PBL shear key and the second PBL shear key have multiple through holes on their surfaces.

[0008] Furthermore, the newly widened steel box girder bridge is provided with a first PBL shear key every 2cm along the longitudinal extension direction of the bridge, and the old widened steel box girder bridge is provided with a second PBL shear key every 2cm along the longitudinal extension direction of the bridge.

[0009] Furthermore, the top plate connection assembly also includes through reinforcing bars, first stirrups, and second stirrups. The through reinforcing bars pass through corresponding through holes on the first PBL shear key and the second PBL shear key, and are fixedly connected to the through holes by welding. A first stirrup is provided on the outer side of all through reinforcing bars on each first PBL shear key. The first stirrup is located on the left side of the first PBL shear key and is fixedly connected to the through reinforcing bars by welding. A second stirrup is provided on the outer side of all through reinforcing bars on each second PBL shear key. The second stirrup is located on the right side of the second PBL shear key and is fixedly connected to the through reinforcing bars by welding.

[0010] Furthermore, within a 30cm radius on both sides of the joint between the newly widened steel box girder bridge and the old widened steel box girder bridge, a 12cm thick layer of UHPC concrete is laid, and an 8cm thick layer of asphalt concrete is laid on the top surface of the UHPC concrete.

[0011] Furthermore, the diaphragm connecting assembly includes connecting plates and high-strength bolts. The connecting plates are provided on the front and rear sides of the diaphragm at the splice joint between the new widened steel box girder bridge and the old widened steel box girder bridge, and the connecting plates are fixedly connected to the corresponding diaphragms by high-strength bolts.

[0012] Furthermore, a stiffening rib is provided at the bottom of the diaphragm splice joint. This stiffening rib is welded after the diaphragm connection assembly of the new widened steel box girder bridge and the old widened steel box girder bridge is spliced.

[0013] In summary, compared with the prior art, the above-described technical solution conceived by this utility model can achieve the following beneficial effects: (1) In the steel box girder splicing structure of this utility model, the top plates of the newly widened steel box girder bridge and the old widened steel box girder bridge are welded to ensure the continuity and integrity of the top plate. The transverse diaphragm is connected by connecting plates and high-strength bolts, which strengthens the overall transverse connection and makes the widened steel box girder form a closely coordinated force-bearing whole. The force transmission is more uniform and smooth, which improves the structural stability and load-bearing capacity.

[0014] (2) The steel box girder splicing structure of this utility model, through the PBL shear key and the through-bar reinforcement, is tightly connected to the top plate of the new and old steel box girder bridge, forming a strong mechanical embedding force. This can effectively ensure that the new and old steel box girders can jointly bear the load under complex working conditions such as vehicle load and temperature changes, so that the two deform together and avoid local damage caused by uneven stress. The PBL shear key can effectively strengthen the area and improve the structural strength and stiffness of the splicing part. In addition, the PBL shear key, together with the top plate welding, stirrups and other structures, can give full play to the dual mechanical properties of bending and shear resistance, effectively disperse and transfer loads, reduce the phenomenon of structural stress concentration, thereby improving the overall load-bearing capacity and stability of the bridge and extending the service life of the bridge.

[0015] (3) The steel box girder splicing structure of this utility model, by setting UHPC concrete at the splicing position, UHPC concrete has ultra-high strength, excellent durability and good toughness. Laying UHPC pavement at the splicing position can effectively enhance the local stiffness of the steel bridge deck in the splicing area, so that the structure can reduce the amount of deformation when subjected to repeated vehicle loads. By increasing the local stiffness, the fatigue stress amplitude of the steel bridge deck can be significantly reduced, effectively weakening or even eliminating the risk of cracking caused by fatigue load, greatly improving the fatigue resistance of the steel bridge deck. The good durability of UHPC pavement can effectively resist the damage to the steel bridge deck caused by environmental factors such as rainwater erosion and chemical corrosion, reduce the cost of later maintenance and repair, and ensure the long-term stable operation of the highway reconstruction and expansion project. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a steel box girder splicing structure used in the reconstruction and expansion of a highway, according to an embodiment of the present utility model. Figure 2 This is a cross-sectional view of a diaphragm connection assembly for a steel box girder splicing structure used in highway reconstruction and expansion, according to an embodiment of the present invention. Figure 3 This is a side view of a transverse diaphragm connection assembly for a steel box girder splicing structure used in highway reconstruction and expansion, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the top plate connection component of a steel box girder splicing structure used in highway reconstruction and expansion, according to an embodiment of the present invention. Figure 5 This is a schematic diagram of a PBL shear key connection structure for a steel box girder splicing structure used in highway reconstruction and expansion, according to an embodiment of this utility model. Figure 6 The following is a structural diagram of an old bridge, illustrating a construction method for a steel box girder splicing structure used in the reconstruction and expansion of a highway, as described in this utility model embodiment. Figure 7Location diagram of an old widened steel box girder bridge, illustrating a construction method for a steel box girder splicing structure used in the reconstruction and expansion of a highway, as described in this utility model embodiment; Figure 8 This is a location diagram of a newly constructed 20.5m steel box girder bridge on the right side of a highway reconstruction and expansion project, according to an embodiment of this utility model. Figure 9 This is a splicing diagram of a newly widened steel box girder bridge and an old widened steel box girder bridge, which is used for the reconstruction and expansion of highways according to an embodiment of this utility model.

[0017] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-New widened steel box girder bridge, 2-Old widened steel box girder bridge, 3-Connecting plate, 4-High-strength bolt, 5-First PBL shear key, 6-Second PBL shear key, 7-Through reinforcement, 8-First stirrup, 9-Second stirrup, 10-UHPC concrete, 11-Diaphragm stiffening rib. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1 like Figure 1-5 As shown in the figure, this embodiment provides a steel box girder splicing structure for highway reconstruction and expansion, including a newly widened steel box girder bridge 1, an old widened steel box girder bridge 2, a top plate connecting assembly, and a diaphragm connecting assembly; the top plates of the newly widened steel box girder bridge 1 and the old widened steel box girder bridge 2 are fixedly connected by welding, and a top plate connecting assembly is provided on the top surface of the top plates of the two; a diaphragm connecting assembly is provided at the diaphragms of the two; no connecting structure is provided between the bottom plates of the newly widened steel box girder bridge and the old widened steel box girder bridge. The top plates of the new widened steel box girder bridge 1 and the old widened steel box girder bridge 2 of this invention are welded and fixedly connected, and in conjunction with the top plate connecting components, which can effectively improve the connection strength and integrity of the top of the new and old widened steel box girder bridges, enhance the load-bearing capacity of the structure under vehicle loads, and ensure driving safety. The connection at the transverse diaphragm is achieved through the transverse diaphragm connecting components, which can optimize the lateral force transmission performance between the new and old steel box girder bridges, make the structure more uniformly stressed, reduce local stress concentration, and extend the service life of the bridge. The bottom plate does not have a connecting structure, which can significantly reduce the construction difficulty and cost while ensuring the stability of the bridge structure, and accelerate the construction progress of the highway reconstruction and expansion project.

[0023] Furthermore, the top plate connection assembly includes a plurality of first PBL shear keys 5 and a plurality of second PBL shear keys 6; the plurality of first PBL shear keys 5 are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the newly widened steel box girder bridge 1 near the splice joint, and the second PBL shear keys 6 are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the old widened steel box girder bridge 2 near the splice joint.

[0024] Furthermore, both the first PBL shear key 5 and the second PBL shear key 6 are made of steel plate, which is 98cm long, 9cm high and 2cm thick, and both the first PBL shear key 5 and the second PBL shear key 6 have multiple through holes on their surfaces.

[0025] Furthermore, the newly widened steel box girder bridge 1 is provided with a first PBL shear key 5 every 2cm along the longitudinal extension direction of the bridge, and the old widened steel box girder bridge 2 is provided with a second PBL shear key 6 every 2cm along the longitudinal extension direction of the bridge.

[0026] Furthermore, the top plate connection assembly also includes through-bars 7, first stirrups 8, and second stirrups 9; wherein, the through-bars 7 are inserted into corresponding through holes on the first PBL shear key 5 and the second PBL shear key 6, and are fixedly connected to the through holes by welding; a first stirrup 8 is provided on the outer side of all through-bars 7 on each first PBL shear key 5, the first stirrup 8 is located on the left side of the first PBL shear key 5, and is fixedly connected to the through-bars 7 by welding; a second stirrup 9 is provided on the outer side of all through-bars 7 on each second PBL shear key 6, the second stirrup 9 is located on the right side of the second PBL shear key 6, and is fixedly connected to the through-bars 7 by welding.

[0027] Furthermore, a 12cm thick UHPC concrete layer is laid within 30cm on both sides of the joint between the newly widened steel box girder bridge 1 and the old widened steel box girder bridge 2. The top surface of the UHPC concrete is covered with an 8cm thick asphalt concrete layer. UHPC concrete possesses extremely high strength, excellent durability, and good toughness. Laying a UHPC pavement layer at the joint effectively enhances the local stiffness of the steel bridge deck in the joint area, reducing deformation when the structure is subjected to repeated vehicle loads. By increasing local stiffness, the fatigue stress amplitude of the steel bridge deck can be significantly reduced, effectively weakening or even eliminating the risk of cracking caused by fatigue loads, and greatly improving the fatigue resistance of the steel bridge deck. The good durability of the UHPC pavement can effectively resist damage to the steel bridge deck from environmental factors such as rainwater erosion and chemical corrosion, reducing later maintenance and repair costs and ensuring the long-term stable operation of the highway reconstruction and expansion project.

[0028] Furthermore, the diaphragm connection assembly includes a connecting plate 3 and high-strength bolts 4. The connecting plate is provided on both the front and rear sides of the diaphragm at the joint between the new widened steel box girder bridge 1 and the old widened steel box girder bridge 2. The connecting plate is fixedly connected to the corresponding diaphragm via high-strength bolts, providing reliable connection strength, effectively transferring the lateral load between the new and old widened steel box girder bridges, enhancing the overall shear resistance and stability of the structure, and ensuring the safe operation of the bridge under complex traffic loads. The high-strength bolt connection construction process does not require complex welding processes or large equipment, and installation and disassembly are convenient, significantly shortening the construction cycle, reducing construction difficulty, and improving the construction efficiency of highway reconstruction and expansion projects. The symmetrical structure of the connecting plate on both sides of the diaphragm allows for more uniform stress distribution, avoiding localized stress concentration that could damage the diaphragm, effectively extending the service life of the bridge structure and reducing subsequent maintenance costs.

[0029] Furthermore, a stiffening rib 11 is provided at the bottom of the diaphragm splice joint. The stiffening rib 11 is welded after the diaphragm connection components of the newly widened steel box girder bridge 1 and the old widened steel box girder bridge 2 are spliced, which effectively enhances the overall stability and load-bearing capacity of the steel box girder structure and ensures its performance under complex load conditions.

[0030] Example 2 like Figure 6-9 As shown in this embodiment, a construction method for a steel box girder splicing structure used in the reconstruction and expansion of a highway is provided. During construction, a 9.5m wide right-side maintenance bridge 2, constructed from the old spliced ​​steel box girder, is first built in the right-side construction area. During construction, the pre-camber is precisely set according to design parameters, and M24 high-strength bolt holes are reserved in the transverse diaphragms on the splicing side. This bridge remains unconnected to the old bridge. Subsequently, the right-side is adjusted to a temporary two-way four-lane maintenance, the left-side is closed, and the old bridge is demolished. Then, a 20.5m wide steel box girder bridge is built in the area where the old bridge on the left-side was demolished. After completion, the left-side is converted to a temporary two-way four-lane maintenance, creating conditions for subsequent construction on the right-side. Once the left-side maintenance is stable, the old right-side bridge is demolished, and a new 13.5m wide right-side spliced ​​steel box girder bridge 1 is built. Afterward, the asphalt pavement, steel fiber reinforced concrete layer, and guardrails of the spliced ​​section of the old spliced ​​steel box girder bridge 2 are removed, and then welded together. The top slabs of the newly widened steel box girder bridge 1 and the old widened steel box girder bridge 2 on the right side are connected. The transverse diaphragms are assembled and connected by splicing plates 3 and high-strength bolts 4, and stiffening ribs 11 are welded to the bottom of the transverse diaphragms. The first PBL shear key 5 and the second PBL shear key 6, made of steel plates with a length of 98cm, a height of 9cm, and a thickness of 2cm, are welded to the new and old widened steel box girder bridges respectively at a distance of 15cm from the splice joint. The 50cm long and 20mm diameter through steel bar 7 is inserted into the hole of the shear key and welded and fixed. The first stirrup 8 and the second stirrup 9 with a diameter of 12mm are welded and fixed to the through steel bar 7 on the outside of the shear key. Finally, 12cm high and 60cm wide UHPC ultra-high performance concrete is poured. After the concrete has cured to the design strength, asphalt paving is carried out. The paving thickness, flatness and compaction are controlled to meet the standards. The guardrail is reconstructed according to the specifications and standards to complete all construction procedures.

[0031] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements 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 steel box girder splicing structure for highway reconstruction and expansion, characterized in that, The bridge includes a new widened steel box girder bridge (1), an old widened steel box girder bridge (2), a top plate connection assembly, and a transverse diaphragm connection assembly. The top plates of the new widened steel box girder bridge (1) and the old widened steel box girder bridge (2) are fixedly connected by welding, and a top plate connection assembly is provided on the top surface of the top plates of the two bridges. No connection structure is provided between the bottom plates. This can effectively improve the connection strength and integrity of the top of the new and old widened steel box girder bridges, enhance the load-bearing capacity of the structure under vehicle load, and ensure driving safety. The new widened steel box girder bridge (1) and the old widened steel box girder bridge (2) are equipped with transverse diaphragm connecting components to optimize the lateral force transmission performance between the new and old steel box girder bridges, making the structure more uniformly stressed and reducing local stress concentration.

2. The steel box girder splicing structure for highway reconstruction and expansion according to claim 1, characterized in that, The top plate connection assembly includes multiple first PBL shear keys (5) and multiple second PBL shear keys (6). The multiple first PBL shear keys (5) are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the newly widened steel box girder bridge (1) near the splice joint. The second PBL shear keys (6) are fixedly installed at intervals along the longitudinal extension direction of the bridge on the top plate of the old widened steel box girder bridge (2) near the splice joint.

3. The steel box girder splicing structure for highway reconstruction and expansion according to claim 2, characterized in that, The first PBL shear key (5) and the second PBL shear key (6) are both made of steel plate. The steel plate is 98cm long, 9cm high and 2cm thick. The first PBL shear key (5) and the second PBL shear key (6) are both provided with multiple through holes on their surfaces.

4. A steel box girder splicing structure for highway reconstruction and expansion according to claim 3, characterized in that, The newly widened steel box girder bridge (1) has a first PBL shear key (5) every 2cm along the longitudinal extension direction of the bridge, and the old widened steel box girder bridge (2) has a second PBL shear key (6) every 2cm along the longitudinal extension direction of the bridge.

5. A steel box girder splicing structure for highway reconstruction and expansion according to any one of claims 1-4, characterized in that, The top plate connection assembly also includes through steel bars (7), first stirrups (8) and second stirrups (9). The through steel bars (7) are inserted into the corresponding through holes on the first PBL shear key (5) and the second PBL shear key (6) and are fixedly connected to the through holes by welding. A first stirrup (8) is provided on the outside of all through steel bars (7) on each first PBL shear key (5). The first stirrup (8) is located on the left side of the first PBL shear key (5) and is fixedly connected to the through steel bars (7) by welding. A second stirrup (9) is provided on the outside of all through steel bars (7) on each second PBL shear key (6). The second stirrup (9) is located on the right side of the second PBL shear key (6) and is fixedly connected to the through steel bars (7) by welding.

6. A steel box girder splicing structure for highway reconstruction and expansion according to any one of claims 1-4, characterized in that, The new widened steel box girder bridge (1) and the old widened steel box girder bridge (2) are paved with 12cm thick UHPC concrete within 30cm on both sides of the splice joint. The top surface of the UHPC concrete is paved with 8cm thick asphalt concrete.

7. A steel box girder splicing structure for highway reconstruction and expansion according to claim 1, characterized in that, The diaphragm connection assembly includes a connecting plate (3) and high-strength bolts (4). The connecting plate is provided on the front and rear sides of the diaphragm at the splice joint between the new widened steel box girder bridge (1) and the old widened steel box girder bridge (2), and the connecting plate (3) is fixedly connected to the corresponding diaphragm by high-strength bolts (4).

8. A steel box girder splicing structure for highway reconstruction and expansion according to claim 7, characterized in that, The bottom of the diaphragm splice joint is provided with a diaphragm stiffening rib (11), which is welded after the diaphragm connection assembly of the new widened steel box girder bridge (1) and the old widened steel box girder bridge (2) is spliced.

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