Composite bridge deck slab structure with built-in folded edges

Abstract

The invention discloses a composite bridge deck structure with built-in folded edges, and belongs to the technical field of bridge engineering. The structure is mainly composed of cold-bending U-shaped steel, transverse penetrating steel bars and a concrete layer. According to the invention, a traditional welding stud connection mode is abandoned, and hook and groove occlusion type mechanical interlocking is formed between the adjacent section steels by utilizing specially-made folding edge structures on the two sides of the cold-bending U-shaped steels, so that the steel skeleton platform without the formwork is quickly assembled. The through holes are preset in the side walls of the section steel, and the transverse steel bars are inserted into the through holes, so that a deep shear mechanism of the steel-concrete interface is constructed. By means of the structure, factory prefabrication and on-site one-key type assembly of the steel members are achieved, the construction efficiency is greatly improved, and the problems of fatigue cracking and corrosion prevention caused by welding are effectively solved. The section steel folded edges and the side walls have the function of longitudinal stress ribs at the same time, unification of light weight and high durability of the structure is achieved, and the structure is suitable for assembly type bridge construction.

Description

Technical Field

[0001] This invention relates to the field of structural engineering technology, specifically to a composite bridge deck structure with folded edges and embedded fastening. Background Technology

[0002] With the rapid development of modern transportation infrastructure, bridge engineering is facing the dual challenges of "large span, lightweight, and high durability" as well as "rapid construction and industrialized building." As the component of a bridge structure that directly bears the repeated loads of vehicle wheels and environmental erosion, the bridge deck has the most complex stress state, determining not only the comfort of driving but also directly affecting the structural safety and service life of the entire bridge. In current bridge construction, steel-concrete composite decks are widely used in long-span suspension bridges, cable-stayed bridges, and urban viaducts because they effectively combine the compressive strength of concrete with the tensile strength of steel, significantly improving the structural load-bearing capacity and reducing the structural self-weight.

[0003] Although steel-concrete composite structures are widely used, the design and construction of their core components—the shear connectors—have long relied on the traditional "welded studs" method. While this method is theoretically sound, it has revealed numerous insurmountable systemic defects in practical engineering applications and long-term operation and maintenance.

[0004] Traditional composite bridge decks rely on densely welded studs to the steel plates to resist interlaminar shear forces. However, the welding process is essentially a thermodynamic process of localized high-temperature heating and rapid cooling. This process inevitably introduces complex residual stress fields into the steel plate base and the stud roots, forming a heat-affected zone that embrittles the material. Under the cyclical action of vehicle loads day after day, these residual stress zones are highly susceptible to becoming initiation sites for fatigue cracks. Once microcracks form, they propagate rapidly under alternating tensile and compressive stresses, leading to fatigue shear failure of the studs or cracking of the steel plate base. This fatigue failure is often insidious and sudden, seriously threatening bridge safety. Furthermore, stud connections are point connections, resulting in significant stress concentration. Local concrete is easily crushed under long-term high stress, leading to degradation of connection stiffness and causing slippage and delamination at the steel-concrete interface.

[0005] To meet shear resistance requirements, traditional bridge deck designs typically require dozens or even hundreds of studs per square meter. Such high-density welding not only results in a lengthy construction period due to the enormous workload, but also demands extremely high levels of skill from welders and stability from welding equipment. In outdoor construction environments, climatic factors such as wind speed and humidity significantly affect welding quality, leading to frequent defects such as incomplete welds and porosity, making it difficult to guarantee consistent quality. Furthermore, in addition to welding studs, traditional bridge decks also require the insertion and binding of complex longitudinal and transverse reinforcing meshes between the studs. This process is not only time-consuming and labor-intensive, but also prone to positional conflicts between the reinforcing mesh and studs, resulting in insufficient concrete cover thickness or inadequate compaction of the poured concrete, further creating potential quality risks.

[0006] To address these issues, the engineering community has experimented with precast concrete deck technology. While this has improved construction speed to some extent, existing precast solutions often employ wet joints or post-cast strips. The interface between the new and old concrete at these joints has poor crack resistance, making it highly susceptible to cracking and water seepage in the early stages of use, leading to steel reinforcement corrosion. Furthermore, some attempts at bolted connections or epoxy resin bonding technologies have failed due to either loose bolts or insufficient durability caused by adhesive aging, failing to perfectly resolve the contradiction between "rapid connection" and "long-term reliability."

[0007] In recent years, cold-formed steel sections have begun to gain attention in bridge engineering due to their advantages such as large cross-section, large radius of gyration, and flexible forming. However, current bridge deck designs based on cold-formed steel sections mostly still use them merely as permanent formwork, or rely on self-tapping screws and spot welding for connections, failing to fully utilize the "geometric interlocking" potential brought by the cold-forming process. Existing technical solutions lack an integrated structural system that can directly form high-strength mechanical interlocking between adjacent components through the folding deformation of the steel sections themselves, while simultaneously serving the function of longitudinal reinforcing bars.

[0008] In summary, against the backdrop of promoting industrialized construction and green construction, there is an urgent need to develop a new type of composite bridge deck system. This system should completely eliminate on-site welding processes, removing residual welding stress and fatigue risks; it should possess the characteristics of high-precision prefabrication in factories, enabling "foolproof" rapid interlocking assembly on-site via mechanical means; and it should, through structural innovation, make the steel sections themselves both formwork and load-bearing skeleton, thereby reducing or even eliminating the use of longitudinal reinforcement. This invention proposes a folded-edge embedded composite bridge deck structure, developed precisely based on the aforementioned industry pain points and technological gaps. It aims to provide a bridge deck solution that combines high load-bearing capacity, high fatigue resistance, and excellent construction efficiency through the unique folded-edge interlocking mechanism of cold-formed U-shaped steel. Summary of the Invention

[0009] The purpose of this invention is to overcome the defects of low construction efficiency and poor fatigue performance of welding connections in the prior art. This invention proposes a composite bridge deck structure with folded edges and embedded fastening. This structure achieves connection through the geometric interlocking of the steel sections themselves, without the need for welding and additional connecting parts, which significantly improves the level of assembly and structural durability.

[0010] A composite bridge deck structure with folded edges and embedded fastening, comprising a composite bridge deck made of cold-formed U-shaped steel, including cold-formed U-shaped steel, transverse through-bar reinforcement, and concrete.

[0011] A further preferred embodiment is a composite bridge deck structure with folded and embedded edges, comprising: An edge U-shaped steel, the edge U-shaped steel including a base plate and side walls provided on both sides of the base plate, the two side walls of the edge U-shaped steel being provided with an inner folded edge structure; Multiple rolled-edge U-shaped steels, each rolled-edge U-shaped steel including a base plate and side walls on both sides of the base plate, each rolled-edge U-shaped steel having an outer edge structure that cooperates with the inner folded edge structure on one side wall, and an inner folded edge structure on the other side wall; The edge U-shaped steel and multiple rolled edge U-shaped steel are arranged continuously side by side along the transverse direction of the bridge deck; Transverse reinforcing bars are inserted through the side walls of the edge U-shaped steel and the side walls of the multiple rolled-edge U-shaped steels; And the concrete poured on the edge U-shaped steel, multiple rolled edge U-shaped steel and transverse reinforcing steel.

[0012] The edge U-shaped steel and the adjacent rolled edge U-shaped steel are fixed to the outer edge structure of the rolled edge U-shaped steel through the inner folded edge structure of the edge U-shaped steel.

[0013] The two adjacent rolled edge U-shaped steels are fixed to the outer edge structure of the next rolled edge U-shaped steel through the inner folded edge structure of the previous rolled edge U-shaped steel.

[0014] The free end of the side wall of the edge U-shaped steel is rotated at a right angle toward the base plate to form a transition plate, and then rotated at a right angle toward the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

[0015] The free end of one side wall of the rolled U-shaped steel is rotated at a right angle away from the base plate to form a cover plate, and then rotated at a right angle towards the side wall to form a folded edge. An L-shaped fixing groove is fixed on the folded edge, and the L-shaped fixing groove cooperates with the protrusion of the inner folded edge structure. The cover plate, the folded edge and the L-shaped fixing groove form the outer edge structure. The free end of the other side wall of the rolled U-shaped steel is rotated at a right angle toward the base plate to form a transition plate, and then rotated at a right angle toward the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

[0016] The sidewalls of the edge U-shaped steel and the sidewalls of the multiple rolled edge U-shaped steels are provided with through holes for the transverse reinforcing bars to pass through, and the transverse reinforcing bars are inserted into the through holes.

[0017] The thickness of the concrete pouring covers the apex of the edge U-shaped steel and the multiple rolled edge U-shaped steel.

[0018] In the composite bridge deck composed of cold-formed U-shaped steel, the cold-formed U-shaped steel is laid continuously in the transverse direction of the bridge deck. Unlike the traditional flat ribbed form, the steel units of this invention are cold-formed on both sides, possessing specific hook-shaped or channel-shaped folded edges. Adjacent steel sections utilize the complementarity of this geometric shape to directly interlock and reinforce each other, thereby forming a continuous and rigidly stable steel frame chassis in the transverse direction.

[0019] In terms of the connection mechanism, the web (sidewall) of the cold-formed U-shaped steel has a row of precisely positioned circular through holes. Transverse through-bars pass directly through these holes, traversing the entire width of the bridge deck. This structure forms a multi-dimensional shear force transfer system: on the one hand, the through-bars act as pins, restricting the relative slippage between the concrete and the steel section, as well as between the steel sections themselves; on the other hand, the folded edge embedment zone at the top of the steel section forms a mechanical anchorage in the concrete. These two elements work together to completely replace traditional welded studs.

[0020] In the composite bridge deck composed of cold-formed U-shaped steel, concrete is poured on the bridge deck steel frame; the thickness of the concrete layer is slightly higher than the height of the folded edges on both sides of the cold-formed U-shaped steel, which plays a role in protecting the bridge deck steel frame, preventing corrosion and improving load-bearing capacity.

[0021] The composite bridge deck structure with folded edges and embedded fastening proposed in this invention is composed of a steel frame formed by cold-formed U-shaped steel, transverse through-bar reinforcement, and concrete, and has the following advantages: (1) Concrete has high compressive bearing capacity, which can effectively isolate steel from the external environment, act as a protective layer, prevent steel from rusting, and thus greatly improve the durability of bridge deck structure.

[0022] (2) Pure mechanical connection, eliminating fatigue risks: By using folded edge interlocking to replace welding, the problem of residual welding stress and thermal damage is completely eliminated, and the fatigue resistance of the structure under dynamic load is greatly improved.

[0023] (3) Reusable components and material savings: Cold-formed U-shaped steel is not only a load-bearing formwork during the construction stage, but also a longitudinal main reinforcement during the service stage. Its folded edge structure provides a huge moment of inertia, eliminating the need for additional longitudinal steel mesh binding and significantly reducing steel consumption.

[0024] (4) Strong shear resistance and strong integrity: The design of transverse steel bars penetrating the web of the steel structure makes the concrete and the steel skeleton form a double interlocking of "pin + wrapping", which has high shear connection stiffness and excellent pull-out performance.

[0025] (5) Rapid construction and green environmental protection: All components can be prefabricated in the factory, and only assembly and reinforcement are required on site, which meets the highest standards of prefabricated buildings and green construction. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the folded-edge embedded composite bridge deck system.

[0027] Figure 2 This is a schematic diagram of the three-dimensional steel frame structure of the bridge deck.

[0028] Figure 3 This is a schematic diagram of a single cold-formed U-shaped steel structure. Detailed Implementation

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] like Figure 1 and Figure 2 As shown, a composite bridge deck structure with folded edges and embedded fastening includes the following components: cold-formed U-shaped steel 1-1 and 1-2, transverse steel bars 2, and concrete 3.

[0031] A composite bridge deck structure with folded edges and embedded fasteners includes several cold-formed U-shaped steels 1-1 and 1-2 arranged continuously side by side along the transverse direction of the bridge deck, transverse through-bars (i.e., transverse bars 2), and three layers of concrete filling the top of the cold-formed U-shaped steels. The top of the two side walls of the cold-formed U-shaped steels 1-1 and 1-2 are provided with folded edge structures formed by the cold bending process. The adjacent cold-formed U-shaped steels are interlocked and interlocked through the geometric matching of the folded edge structures, thereby forming a mechanically interlocked steel frame bottom formwork system in the transverse direction of the bridge.

[0032] The folded structure includes a hook-shaped fold formed on one side of the steel profile and a channel-shaped fold formed on the other side; adjacent cold-formed U-shaped steel profiles are embedded in the channel-shaped fold through the hook-shaped fold, forming a continuous tensile and shear-resistant embedded joint. The embedded joint establishes the overall stability of the steel frame before the concrete is poured.

[0033] The sidewall of the cold-formed U-shaped steel has a pre-set through hole corresponding to the axis position. The transverse through bar passes through the through hole and spans multiple cold-formed U-shaped steels 1-1 and 1-2. The transverse through bar and the through hole cooperate to form a shear key, which together with the embedded area formed by the folded edge structure constitutes a shear-resistant connection and anti-slip system between the steel skeleton and the concrete layer.

[0034] The concrete is poured in three layers and covers the steel frame. The thickness of the concrete covers the folded apex of the cold-formed U-shaped steel 1-1 and 1-2, so that the steel frame is in a protective environment of concrete. The alkaline environment of the concrete inhibits the corrosion of the steel.

[0035] The edge U-shaped steel 1-1 includes a base plate and side walls on both sides of the base plate. The two side walls of the edge U-shaped steel are provided with an inner folded edge structure. The free end of the side wall of the edge U-shaped steel 1-1 is rotated at a right angle toward the base plate to form a transition plate, and then rotated at a right angle toward the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

[0036] The rolled-edge U-shaped steel 1-2 includes a base plate and side walls on both sides of the base plate. One side wall of the rolled-edge U-shaped steel has an outer edge structure that cooperates with the inner folded edge structure, and the other side wall of the rolled-edge U-shaped steel has an inner folded edge structure. The free end of one side wall of the rolled-edge U-shaped steel 1-2 rotates at a right angle away from the base plate to form a cover plate, and then rotates at a right angle towards the side wall to form a folded edge. An L-shaped fixing groove is fixed on the folded edge, and the L-shaped fixing groove cooperates with the protrusion of the inner folded edge structure. The cover plate, the folded edge, and the L-shaped fixing groove form the outer edge structure. The free end of the other side wall of the rolled-edge U-shaped steel 1-2 rotates at a right angle towards the base plate to form a transition plate, and then rotates at a right angle towards the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

[0037] Edge U-shaped steel 1-1 and multiple rolled edge U-shaped steel 1-2 are arranged continuously side by side along the transverse direction of the bridge deck; the edge U-shaped steel 1-1 and the adjacent rolled edge U-shaped steel 1-2 are fixed to the outer edge structure of the rolled edge U-shaped steel 1-2 through the inner folded edge structure of the edge U-shaped steel 1-1.

[0038] The two adjacent rolled edge U-shaped steels 1-2 are fixed to the outer edge structure of the next rolled edge U-shaped steel 1-2 through the inner folded edge structure of the previous rolled edge U-shaped steel 1-2.

[0039] During implementation, the steel frame is assembled first. For example... Figure 2 As shown, multiple cold-formed U-shaped steel sections 1-1 are arranged side-by-side transversely on the bridge deck, while cold-formed U-shaped steel sections 1-2 are arranged at the bridge edge to form a complete structure. For example... Figure 3 As shown, components 1-1 and 1-2 have geometrically complementary folded edge areas at their top edges. During installation, a simple pressing operation causes the folded edge areas of adjacent steel sections to mechanically interlock. This "interlocking" connection method allows multiple steel sections to instantly form a rigid steel frame platform without any temporary support or welding fixation, greatly simplifying the on-site operation process.

[0040] like Figure 3 As shown, coaxial circular through holes are pre-stamped on the sidewall webs of steel sections 1-1 and 1-2 at the factory. After assembly, transverse through reinforcing bars 2 are sequentially passed through these through holes. The presence of reinforcing bars 2 not only locks the relative positions of the steel sections and prevents lateral deformation during casting, but also serves as a core shear key in the later stages, bearing the shear force transfer between the steel and concrete.

[0041] Finally, as Figure 1As shown, concrete 3 is poured on top of the steel frame. The concrete fills the interior of the U-shaped channel and the gaps between the channels, covering a certain thickness above the top of the folded edge. The hardened concrete, together with the embedded steel sections and the transverse reinforcing bars, forms this tightly integrated load-bearing structure. The folded edges of the steel sections not only serve a connecting function but also act as "stiffening ribs" penetrating deep into the concrete, providing additional pull-out resistance and longitudinal bending stiffness, thus achieving a comprehensive leap in structural performance.

[0042] This embodiment constructs a multi-dimensional composite shear-resistant system. Traditional composite structures rely solely on the "point-to-point" shear resistance of studs, which carries the risk of stress concentration and localized crushing. In this invention, the interlocking structure of the folded edges at the top of the cold-formed U-shaped steel forms a continuous longitudinal "mechanical interlocking band" within the concrete, providing strong linear shear and pull-out restraint. Simultaneously, the transverse through-bar reinforcement acts like "pins," connecting the concrete and multiple steel webs laterally, forming a deep shear force transfer mechanism. This dual mechanism of "continuous surface interlocking + deep transverse pinning" not only significantly improves the interface's anti-slip stiffness but also effectively suppresses local buckling of the steel by utilizing the concrete's encapsulation effect, achieving perfect synergistic stress distribution between steel and concrete. Furthermore, in traditional solutions, the welding of dozens of studs per square meter inevitably introduces dense heat-affected zones and residual stress fields into the steel plate base material. These areas are highly susceptible to becoming sources of fatigue crack initiation under long-term dynamic loads on bridges. The fully cold-bending mechanical connection employed in this invention completely eliminates the metallographic changes and thermal damage caused by welding, preserving the original toughness and strength of the steel, thereby fundamentally extending the fatigue life of the bridge deck. Furthermore, the complete protective coverage of the steel frame by the concrete layer creates a stable alkaline environment, blocking the intrusion of corrosive media from both physical and chemical perspectives.

[0043] This invention completely abandons traditional welding connections and adopts a highly efficient mechanical embedding mechanism, effectively avoiding problems such as welding residual stress, construction errors, and fatigue damage. Simultaneously, the steel plates on both sides of the cold-formed U-shaped steel possess excellent load-bearing performance, allowing them to replace the function of longitudinal reinforcing bars in the structural design. This eliminates the need for additional longitudinal reinforcing bars in the bridge deck, further reducing the construction steps of reinforcing bar binding and meshing, significantly reducing structural material consumption, and greatly improving overall construction efficiency and on-site assembly speed.

[0044] In summary, the composite bridge deck structure with folded and embedded joints proposed in this invention successfully establishes a novel "seamless, self-locking" steel-concrete composite system through geometric innovation at the component level and mechanistic reconstruction at the connection level. It replaces the uncertainties of on-site welding with the precision of industrial prefabrication, and replaces the fragility of chemical bonding or welding connections with the reliability of mechanical interlocking. This structure not only meets the stringent requirements of modern bridge engineering for high load-bearing capacity and long service life, but also aligns with the technological orientation of the construction industry towards prefabrication, greening, and rapid development, possessing extremely high engineering practical value and promising prospects for widespread application.

Claims

1. A composite bridge deck structure with folded and embedded edges, characterized in that, include: An edge U-shaped steel, the edge U-shaped steel including a base plate and side walls provided on both sides of the base plate, the two side walls of the edge U-shaped steel being provided with an inner folded edge structure; Multiple rolled-edge U-shaped steels, each rolled-edge U-shaped steel including a base plate and side walls on both sides of the base plate, each rolled-edge U-shaped steel having an outer edge structure that cooperates with the inner folded edge structure on one side wall, and an inner folded edge structure on the other side wall; The edge U-shaped steel and multiple rolled edge U-shaped steel are arranged continuously side by side along the transverse direction of the bridge deck; Transverse reinforcing bars are inserted through the side walls of the edge U-shaped steel and the side walls of the multiple rolled-edge U-shaped steels; And the concrete poured on the edge U-shaped steel, multiple rolled edge U-shaped steel and transverse reinforcing steel.

2. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The edge U-shaped steel and the adjacent rolled edge U-shaped steel are fixed to the outer edge structure of the rolled edge U-shaped steel through the inner folded edge structure of the edge U-shaped steel.

3. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The two adjacent rolled edge U-shaped steels are fixed to the outer edge structure of the next rolled edge U-shaped steel through the inner folded edge structure of the previous rolled edge U-shaped steel.

4. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The free end of the side wall of the edge U-shaped steel is rotated at a right angle toward the base plate to form a transition plate, and then rotated at a right angle toward the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

5. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The free end of one side wall of the rolled U-shaped steel is rotated at a right angle away from the base plate to form a cover plate, and then rotated at a right angle towards the side wall to form a folded edge. An L-shaped fixing groove is fixed on the folded edge, and the L-shaped fixing groove cooperates with the protrusion of the inner folded edge structure. The cover plate, the folded edge and the L-shaped fixing groove form the outer edge structure. The free end of the other side wall of the rolled U-shaped steel is rotated at a right angle toward the base plate to form a transition plate, and then rotated at a right angle toward the base plate to form a protrusion. The transition plate and the protrusion form the inner folded edge structure.

6. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The sidewalls of the edge U-shaped steel and the sidewalls of the multiple rolled edge U-shaped steels are provided with through holes for the transverse reinforcing bars to pass through, and the transverse reinforcing bars are inserted into the through holes.

7. The composite bridge deck structure with folded edges and embedded fastening according to claim 1, characterized in that, The thickness of the concrete pouring covers the apex of the edge U-shaped steel and the multiple rolled edge U-shaped steel.

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