Box-shaped bridge structure adopting tough concrete-corrugated steel composite webs

Abstract

The invention provides a box-shaped bridge structure adopting tough concrete-corrugated steel composite webs, which consists of the corrugated steel composite webs, shear connectors and ultrahigh-toughness concrete, and is characterized in that corrugated steel is longitudinally arranged along a bridge deck and partially extends into an upper concrete flange and a lower concrete flange, and a round hole is formed in an extending section for transverse steel bars to penetrate through; a shear connector is formed; the outer side of the corrugated steel web and the outer sides of the upper flange and the lower flange of the bridge are each thinly coated with a layer of ultrahigh-toughness concrete. The ultrahigh-toughness concrete disclosed by the invention can be used for improving the crack resistance, seepage resistance, corrosion resistance and durability of a structure; the corrugated steel webs do not need dense stiffening ribs, the steel consumption and welding operation are reduced, and the corrugated steel webs are suitable for large-span soft foundations and earthquake high-intensity areas; the shearing force connecting piece replaces a traditional stud, stud cost and welding fatigue influences are avoided, the construction period is shortened, and material cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of structural engineering technology, specifically to a box bridge structure using a tough concrete-corrugated steel composite web. Background Technology

[0002] With the continuous development of my country's transportation infrastructure, people have realized that the convenience of urban and intercity transportation greatly affects national economic development and social progress. Therefore, bridge engineering has placed higher demands on construction efficiency, material economy, and structural durability. Bridge structures are widely used not only in urban overpasses, subways, light rail, and high-speed railways, but also in cross-river and cross-sea structures. In recent years, with the construction of mega-bridge projects such as the Hong Kong-Zhuhai-Macau Bridge and the Hangzhou Bay Bridge, bridge structures both domestically and internationally are facing unprecedented development opportunities. Currently, traditional concrete box girder bridges, widely used in bridge structures, employ reinforced concrete or prestressed concrete as the core material. They form a closed box section enclosed by top and bottom slabs, webs, and diaphragms. The top and bottom flanges serve as the main load-bearing components, bearing the bending moments and axial forces generated during bridge operation; the webs are vertical load-bearing components, connecting the top and bottom flanges and transmitting shear forces. The closed section of traditional concrete box girder bridge structures gives the structure excellent bending, shear and torsional resistance. Under load, the internal forces are evenly distributed, which can effectively disperse the impact of concentrated loads on local sections.

[0003] However, traditional concrete box girder bridges suffer from excessive self-weight, with the concrete web accounting for a high proportion of the structural load-bearing capacity. Simultaneously, the shrinkage, creep, and temperature variations in concrete lead to stress concentration at the junction of the web and the top and bottom slabs, causing cracks and severely impacting structural durability and safety. Traditional concrete-corrugated steel composite web box girder bridges utilize corrugated steel composite webs instead of concrete webs, solving these problems. First, they avoid cracking caused by shrinkage, creep, and temperature variations in the concrete web, improving structural durability and safety and mitigating the risk of cracking under complex stress conditions. Second, they significantly reduce the weight of the web, decreasing the amount of substructure and foundation work and improving material utilization. Third, compared to traditional concrete-flat steel composite web box girder bridges, the use of corrugated steel plates as the web enhances structural load-bearing capacity.

[0004] Despite the significant advantages of traditional concrete-corrugated steel composite web box girder bridges, several issues remain to be addressed. First, the transverse bending stiffness of the corrugated steel web is much lower than that of the concrete web, leading to a decrease in the transverse stiffness of the box girder section. This makes it prone to lateral deformation and warping, and under eccentric loads, the distortion effect of the box girder section is significant, affecting driving comfort and safety. Second, in long-span bridges, the high height-to-thickness ratio of the corrugated steel web makes it susceptible to local buckling under compressive stress, affecting structural safety. The corrugated steel web also reduces the longitudinal stiffness of the bridge, exacerbating stability issues under axial pressure. Third, the stress distribution at the connection between the corrugated steel web and the concrete top and bottom slabs is complex, making it prone to fatigue cracks under repeated vehicle loads. The long-term performance of the shear connection requires further verification. Summary of the Invention

[0005] To address the problems of traditional concrete-corrugated steel composite web box girder bridges, this invention proposes a box girder bridge structure using a tough concrete-corrugated steel composite web. This aims to solve the problems of excessive self-weight and easy cracking of the web in traditional concrete box girder bridges, as well as insufficient lateral stiffness, easy local buckling of the corrugated steel web, and easy fatigue cracking at the steel-concrete connection points in existing concrete-corrugated steel composite web bridges.

[0006] The box girder bridge structure employing a tough concrete-corrugated steel composite web includes: an upper composite flange plate comprising a regular concrete flange plate and an upper ultra-high toughness concrete flange plate; a lower composite flange plate comprising a regular concrete flange plate and a lower ultra-high toughness concrete flange plate; and a composite web plate for bearing the shear force of the bridge structure, wherein the composite web plate is disposed between the upper composite flange plate and the lower composite flange plate, and the composite web plate comprises a corrugated steel web plate, a regular concrete web plate, and an ultra-high toughness concrete web plate.

[0007] The ultra-high toughness concrete described in this invention can be used to improve the crack resistance, impermeability, corrosion resistance and durability of structures; the corrugated steel web does not require dense stiffening ribs, reducing steel consumption and welding operations, and is suitable for large spans, soft foundations and high-intensity earthquake zones; shear connectors replace traditional studs, avoiding stud costs and welding fatigue effects, shortening the construction period and reducing material costs.

[0008] The box girder bridge structure with tough concrete-corrugated steel composite web is described above. The ordinary concrete is the ordinary concrete specified in the "Specification for Mix Proportion Design of Ordinary Concrete (JGJ55-2011)".

[0009] The box girder bridge structure using a tough concrete-corrugated steel composite web is wherein ordinary concrete is poured into the troughs of the corrugated steel web to form the ordinary concrete web.

[0010] The box girder bridge structure using tough concrete-corrugated steel composite web has an ultra-high toughness concrete web formed by uniformly pouring a layer of ultra-high toughness concrete on the outside of the ordinary concrete at the trough of the corrugated steel web and on the surface of the crest of the corrugated steel web.

[0011] The box girder bridge structure using a tough concrete-corrugated steel composite web has an upper edge of the corrugated steel web extending into the concrete flange of the upper composite flange of the bridge. Transverse steel bars are horizontally inserted and pass through the corrugated steel web via circular holes to form an integrated shear connector.

[0012] The box girder bridge structure using a tough concrete-corrugated steel composite web is characterized in that the lower edge of the corrugated steel web extends into the concrete flange of the lower composite flange of the bridge, and transverse steel bars are horizontally inserted and pass through the corrugated steel web through round holes to form an integrated shear connector.

[0013] The ultra-high toughness concrete used in this invention comprises cement, active mineral admixtures, aggregates, reinforcing fibers, and water, wherein the cement and active mineral admixtures are made from the following raw materials in weight percentages: Cement: 12%~55%; Fly ash: 45%~85%; Silica fume: 0~15%; Granulated blast furnace slag: 0~10%; Metakaolin: 0~20%.

[0014] The preferred raw materials are those with the following weight percentages: Cement: 30%; Fly ash: 50%; Silica fume: 7%; Granulated blast furnace slag: 5%; Metakaolin: 8%.

[0015] The ultra-high toughness concrete layer is used to protect the concrete flanges of the bridge deck from external damage and extend the service life of the bridge deck.

[0016] The ultra-high toughness concrete layer and the ordinary concrete flange plate work together to bear the bending moment and local load during bridge operation, improve the crack resistance and load-bearing capacity of the bridge deck structure, and ensure traffic safety and structural stability.

[0017] The box girder bridge structure with a tough concrete-corrugated steel composite web proposed in this invention is composed of corrugated steel composite web, shear connectors, and ultra-high toughness concrete, and has the following advantages: (1) The ultra-high toughness concrete used has high compressive bearing capacity, exhibits strain hardening characteristics under tension, and can stably reach more than 3% ultimate tensile strain. Under ultimate tensile strain, only densely distributed fine cracks appear, which can effectively isolate steel from the external environment, prevent steel corrosion, and improve the toughness, corrosion resistance and durability of the bridge deck structure.

[0018] (2) The invented bridge structure adopts corrugated steel web, fundamentally breaking through the inherent limitations of traditional concrete web in bridge engineering through innovation in materials and structural form. This structure significantly reduces the load on the substructure and the scale of foundation engineering, especially providing better adaptability for the construction of bridges with long spans, soft foundations, and high seismic intensity zones. Its unique folded structure significantly improves the durability and service life of the structure, while allowing the prestressing tendons to be fully concentrated on the top and bottom plates, giving full play to the mechanical properties of the materials. In addition, the folded structure of the corrugated steel web fundamentally solves the key problem of insufficient buckling resistance of flat steel web.

[0019] (3) The bridge structure invented uses corrugated steel web, which avoids the problems of dense stiffening ribs, extensive welding operations during factory processing, and complex node handling during on-site assembly when using flat steel web; while the corrugated steel web structure is simple and can be continuously formed using an automated production line during factory prefabrication; at the same time, its characteristic of not needing dense stiffening ribs reduces the amount of steel used, combined with the savings in foundation engineering brought about by lightweighting.

[0020] (4) The corrugated steel of the bridge structure is arranged longitudinally along the bridge deck and partially extends into the upper and lower concrete flanges. The corrugated steel extends into the concrete in a short length and has a row of round holes. The transverse steel bars pass through the round holes and thus act as the reinforcing steel bars of the bridge deck. The connection between the corrugated steel web and the concrete flange reduces relative slippage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the bridge structure.

[0022] Figure 2 This is a schematic diagram of a corrugated steel web structure.

[0023] Figure 3 This is a horizontal cross-sectional view of a corrugated steel web structure.

[0024] Figure 4 This is a schematic diagram of a shear connection where the corrugated steel web extends into the concrete flange. Detailed Implementation

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] like Figure 1 , Figure 2 and Figure 4 As shown, a box girder bridge structure using a tough concrete-corrugated steel composite web includes the following components: a thin layer of ultra-high toughness concrete 1 on the upper flange, a layer of ordinary concrete 2 on the upper flange, a corrugated steel web 3, a thin layer of ultra-high toughness concrete 4 on the outer side of the corrugated steel web 3, an ordinary concrete layer 5 on the lower flange, a thin layer of ultra-high toughness concrete 6 on the lower flange, ordinary concrete 7 filling the troughs on the outer side of the corrugated steel web 3, and transverse reinforcing bars 8.

[0027] like Figure 1 and Figure 4 As shown, corrugated steel is arranged longitudinally along the bridge deck and partially extends into the upper and lower concrete flanges. The portion of the corrugated steel extending into the concrete is relatively short and has a row of round holes. The transverse reinforcing bars 8 pass through the round holes to form shear connectors that connect to the flanges.

[0028] like Figure 2 and Figure 3 As shown, the outer side of the corrugated steel web of the box section is filled with ordinary concrete 7 in the troughs, and a thin layer of ultra-high toughness concrete 3 is applied to the outer side.

[0029] like Figure 1 As shown, ultra-high toughness concrete is poured on the outer sides of the upper and lower flanges of the box girder bridge to protect the bridge deck and bear the load.

[0030] The ultra-high toughness concrete used in this invention comprises cement, active mineral admixtures, aggregates, fibers, and water. The active mineral admixtures include fly ash, silica fume, granulated blast furnace slag, and metakaolin. The maximum particle size of the aggregates does not exceed 0.5 mm. The fibers are polyvinyl alcohol fibers with a length of 12 mm, a diameter of 0.04 mm, an elastic modulus of 40 GPa, a tensile strength of 1600 MPa, and an ultimate elongation of 6%. The weight ratio of each component of cement and active mineral admixtures is as follows: Cement: 30%; Fly ash: 50%; Silica fume: 7%; Granulated blast furnace slag: 5%; Metakaolin: 8%.

[0031] Performance tests on the ultra-high toughness concrete obtained under the above mix proportions show that its uniaxial tensile strength can reach 5.7 MPa (1.3 times that of concrete of equivalent strength), its ultimate tensile strain can reach 3.2% (approximately 320 times that of concrete), and the crack width corresponding to the ultimate tensile strain is 0.049 mm; its flexural strength is 12.8 MPa (approximately twice that of concrete), its uniaxial compressive strength is 48 MPa, and the compressive strain corresponding to the peak load is 0.55% (approximately twice that of concrete).

[0032] This invention belongs to the field of structural engineering technology. It addresses the problems of insufficient lateral stiffness, easy local buckling of corrugated steel web, and easy fatigue cracking at the steel-concrete connection of traditional concrete-corrugated steel composite web box girder bridges. It proposes a box girder bridge structure with tough concrete-corrugated steel composite web. The core is composed of corrugated steel composite web, shear connectors and ultra-high toughness concrete, which significantly improves the overall performance of the structure and reduces the engineering cost. The key technical structure of this invention includes three aspects: First, corrugated steel is arranged longitudinally along the bridge deck, with some extending into the upper and lower concrete flanges. The extended sections have openings for transverse reinforcing bars to pass through, forming shear connectors and effectively reducing relative slippage at the steel-concrete interface. Second, the outer troughs of the corrugated steel web are filled with ordinary concrete, and a thin layer of ultra-high toughness concrete is applied to the outer side and the outer sides of the upper and lower flanges of the bridge, taking into account both load-bearing and protective functions. Third, the ultra-high toughness concrete is composed of cement, fly ash, silica fume and other active mineral admixtures, aggregates, reinforcing fibers and water, with a clear weight ratio of each component. Its uniaxial tensile strength can reach 5.7%, and its ultimate tensile strain can reach 3.2%, with bending and compressive properties far exceeding those of ordinary concrete. In this invention, ultra-high toughness concrete generates dense fine cracks that effectively block external environmental erosion of the steel, significantly improving the structure's crack resistance, impermeability, corrosion resistance, and durability. Simultaneously, the corrugated steel web, through its unique pleated structure, solves the problem of requiring dense stiffening ribs in flat steel webs, reducing welding operations and steel consumption while improving buckling resistance. Furthermore, the shear connection structure combining transverse reinforcement with perforated corrugated steel avoids the material and construction costs of traditional studs and the negative impact of welding on fatigue performance. Through material innovation and structural optimization, this invention systematically solves the core technical pain points of traditional composite web bridges, improving structural toughness, durability, and safety while optimizing engineering costs and construction efficiency, possessing broad potential for widespread application in bridge structures.

Claims

1. A box girder bridge structure employing a tough concrete-corrugated steel composite web, characterized in that, include: The bridge superstructure composite flange plate includes a concrete flange plate and an upper ultra-high toughness concrete flange plate; The bridge substructure composite flange includes a concrete flange and a lower ultra-high toughness concrete flange. A composite web for bearing the shear force of a bridge structure, wherein the composite web is disposed between the upper composite flange plate and the lower composite flange plate of the bridge, and the composite web includes corrugated steel web, ordinary concrete web and ultra-high toughness concrete web.

2. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 1, characterized in that, The ordinary concrete referred to is the ordinary concrete specified in the "Specification for Mix Proportion Design of Ordinary Concrete (JGJ55-2011)".

3. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 2, characterized in that, Ordinary concrete is poured into the troughs of the corrugated steel web to form the ordinary concrete web.

4. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 1, characterized in that, On the outside of the ordinary concrete at the trough of the corrugated steel web and on the surface of the crest of the corrugated steel web, a layer of ultra-high toughness concrete is uniformly poured to form the ultra-high toughness concrete web.

5. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 1, characterized in that, The upper edge of the corrugated steel web extends into the concrete flange of the upper composite flange of the bridge, and transverse steel bars are horizontally inserted and pass through the corrugated steel web through round holes to form an integrated shear connector.

6. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 1, characterized in that, The lower edge of the corrugated steel web extends into the concrete flange of the lower composite flange of the bridge, and transverse steel bars are horizontally inserted and pass through the corrugated steel web through round holes to form an integrated shear connector.

7. The box girder bridge structure with a tough concrete-corrugated steel composite web as described in claim 1, characterized in that, The concrete flanges of the upper composite flange plate, the lower composite flange plate, and the ultra-high toughness concrete web of the bridge are all made of ultra-high toughness concrete, including cement, active mineral admixtures, aggregates, reinforcing fibers, and water. The cement and active mineral admixtures are made from the following raw materials by weight percentage: Cement: 12%~55%; Fly ash: 45%~85%; Silica fume: 0~15%; Granulated blast furnace slag: 0~10%; Metakaolin: 0~20%.

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