Pi-shaped high-strength steel-UHPC (Ultra High Performance Concrete) combined unit and combined beam

Abstract

The utility model provides a pi-shaped high-strength steel-UHPC (Ultra High Performance Concrete) combined unit, and belongs to the technical field of bridge structures. The middle part of the pi-shaped high-strength steel is provided with a steel inner support, and the outer side of the pi-shaped high-strength steel is provided with a steel inclined support; the UHPC bridge deck slab is laid on the two webs of the pi-shaped high-strength steel and the steel inner support; the waterproof bonding layer is laid on the UHPC bridge deck slab; and the asphalt concrete pavement layer is paved on the waterproof bonding layer. The UHPC bridge deck slab and the pi-shaped high-strength steel are combined for use, the working condition of the wearing layer is effectively improved through the UHPC bridge deck slab, the risk of rutting, cracking and other diseases of the wearing layer can be reduced, the overall rigidity of the combined structure is greatly improved, the stress state of the UHPC bridge deck slab and the asphalt concrete pavement layer is remarkably improved, and the service life of the pavement layer is prolonged. And the possibility of fatigue damage of the pi-shaped high-strength steel structure is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge structures, in particular to a π-shaped high-strength steel-UHPC composite unit and a π-shaped high-strength steel-UHPC composite beam comprising the π-shaped high-strength steel-UHPC composite unit. Background Art

[0002] With the rapid development of the processing and application of steel box girders, the number of steel-concrete composite beam bridges is increasing continuously. Especially in long-span highway bridges, steel-concrete composite beams are favored and concerned by more and more bridge engineers due to their good torsional resistance, fast construction speed, and the ability to avoid traffic impact during construction. Currently, prefabricated construction is an innovation in construction methods. The prefabricated components processed modularly in the factory are transported to the construction site and assembled integrally by hoisting. Prefabricated construction has the characteristics of standardized design, modular products, factory production, mechanized assembly, and refined management, and has great advantages in energy conservation, emission reduction, environmental protection, etc. Therefore, the application of prefabricated technology in bridge construction has received extensive attention from domestic and foreign scholars. The traditional fully prefabricated ordinary concrete beam has a large hoisting weight, which brings great difficulties to transportation and installation. Although the all-steel structure beam is lighter in weight, its cost is expensive. In the existing steel-concrete composite beams, the material stiffness of the steel beam and ordinary concrete varies greatly. The concrete section is usually made relatively large, making it difficult to achieve structural lightness. In addition, the brittle failure characteristics of concrete itself and its performance degradation problems in specific environments, such as the spalling of the protective layer caused by steel bar corrosion, structural damage under low damage tolerance, and cracking in the negative moment area of continuous beams, greatly affect the overall durability, safety, and economy of the bridge and are prone to become the weak points of the composite structure bridge system. In view of the above bottlenecks, it is particularly important to develop a new type of steel-concrete composite structure with light hoisting weight, good economy, and fast prefabricated construction.

[0003] Ultra-high performance concrete (UHPC), as a new type of high-performance civil engineering material, has ultra-high compressive strength and good durability, and its compressive strength can reach more than 150 MPa. High-strength steel (generally referring to steel with a yield strength greater than 460 MPa) has the characteristics of high strength, good toughness, excellent mechanical and welding processing performance, etc. Making full use of its super tensile performance can greatly reduce the self-weight of the structure. Combining the excellent properties of UHPC and high-strength steel, the utility model proposes a design scheme for a prefabricated π-shaped high-strength steel-UHPC composite beam structure, which makes full use of the ultra-high compressive performance of UHPC and the super tensile performance of high-strength steel to achieve the light weight of the steel-concrete composite beam and the convenience and speed of construction.

[0004] Steel bridges have advantages such as light weight, high strength, and recyclability. However, orthotropic steel bridge decks are commonly used in large and medium-span steel bridges. There are two major problems in the actual use of this type of steel bridge deck: First, orthotropic steel bridge decks are prone to fatigue cracks under heavy traffic; second, the steel bridge deck pavement is extremely vulnerable to damage, such as diseases like pavement cracking, pushing, potholes, and ruts, which seriously affect the normal use of the bridge. Summary of the Invention

[0005] In view of this, to solve the technical problems of the existing steel bridge deck being prone to fatigue cracks and its pavement being vulnerable to damage, on the one hand, the present utility model provides a π-shaped high-strength steel-UHPC composite unit. By using the combination of UHPC bridge deck and π-shaped high-strength steel, the working conditions of the wearing course can be effectively improved by the UHPC bridge deck, the risk of diseases such as rutting and cracking in the wearing course can be reduced, the overall stiffness of the composite structure is greatly improved, the stress states of the UHPC bridge deck and the asphalt concrete pavement are significantly improved, and the possibility of fatigue failure of the π-shaped high-strength steel structure is greatly reduced.

[0006] To achieve the above object, the present utility model provides the following technical solutions:

[0007] A π-shaped high-strength steel-UHPC composite unit, comprising:

[0008] π-shaped high-strength steel, with a steel inner brace provided in the middle and steel diagonal braces provided on the outside;

[0009] UHPC bridge deck, which is laid on the two webs of the π-shaped high-strength steel and the steel inner brace;

[0010] Waterproof bonding layer, which is laid on the UHPC bridge deck;

[0011] Asphalt concrete pavement, which is laid on the waterproof bonding layer.

[0012] Preferably, it further includes:

[0013] Shear keys, which are arranged in the longitudinal and transverse wet joints of the UHPC bridge deck, the steel inner brace, and the flange transverse connection grooves of the UHPC bridge deck.

[0014] Preferably, the steel mesh of the UHPC bridge deck is arranged between the shear keys.

[0015] Preferably, the width of the longitudinal and transverse wet joints is between 50 and 100 cm.

[0016] Preferably, the steel diagonal braces and the steel inner brace are located at the same cross-section.

[0017] Preferably, the steel diagonal braces and the steel internal braces are arranged within the range of 1 / 3 to 1 / 2 of the web height of the π-shaped high-strength steel, with a thickness of more than 20 cm and a longitudinal bridge spacing of 5 to 7 m.

[0018] Preferably, the shear keys provided on the longitudinal and transverse wet-cast joints and the steel internal braces are stud shear keys.

[0019] Preferably, the steel diagonal braces have a rectangular solid cross-section, and the steel internal braces adopt a Γ-shaped cross-section at the ends and a T-shaped cross-section at the mid-span.

[0020] On the other hand, the present utility model also provides a π-shaped high-strength steel-UHPC composite beam, which is formed by connecting a plurality of the above-mentioned π-shaped high-strength steel-UHPC composite units in series and in parallel.

[0021] Preferably, a plurality of the π-shaped high-strength steels are fixedly connected at the transverse connection grooves of the flanges of the π-shaped high-strength steel.

[0022] The present utility model has the following beneficial effects compared with the prior art:

[0023] The π-shaped high-strength steel-UHPC composite unit provided by the present utility model, by using the combination of the UHPC bridge deck and the π-shaped high-strength steel, can effectively improve the working conditions of the wearing course by using the UHPC bridge deck, reduce the risk of diseases such as rutting and cracking in the wearing course, greatly improve the overall stiffness of the composite structure, significantly improve the stress state of the UHPC bridge deck and the asphalt concrete paving layer, and greatly reduce the possibility of fatigue failure of the π-shaped high-strength steel structure. It has the following beneficial effects compared with the prior art:

[0024] (1) The composite unit and the composite beam of the present utility model give full play to the use efficiency of high-strength steel and UHPC materials, fully embody the beneficial effects of the material combination, and have the advantages of good durability, light structure, excellent mechanical properties, high load-bearing capacity, and convenient construction. It is particularly suitable for the prefabricated π-shaped high-strength steel-UHPC composite beam structure with steel diagonal and internal braces for large and medium-span bridges.

[0025] (2) The π-shaped high-strength steel-UHPC composite beam of the present utility model can solve the problems of fatigue cracks in the steel bridge deck and the easy damage of its paving layer, as well as the problems of the large self-weight of ordinary concrete in the existing steel-concrete composite beam, the brittle failure characteristics of the concrete itself, and its performance degradation under specific environments.

[0026] (3) The π-shaped high-strength steel-UHPC composite beam of the present utility model fully realizes the efficient integration of the ultra-high compressive performance of UHPC and the ultra-high tensile performance of high-strength steel. When applied to the upper structure of a bridge, it can not only maximize the excellent mechanical properties of the materials, but also achieve the lightening of the structure.

[0027] (4) The π-shaped high-strength steel, steel diagonal braces, steel internal braces, and shear keys of the present utility model can all be prefabricated and welded in the factory, and the UHPC bridge deck can be precast and poured on-site, which can achieve the standardization, factoryization, and large-scale production of components, and shorten the construction period.

[0028] (5) The π-shaped high-strength steel-UHPC composite beam of the present utility model has the advantages of "green, environmental protection, light weight, high strength, and economy", with high comprehensive social benefits, and is particularly suitable for large-scale applications in large and medium-span bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a three-dimensional schematic diagram of the composite beam of the present utility model;

[0030] Figure 2 is a standard cross-sectional view of the composite beam of the present utility model;

[0031] Figure 3 is a three-dimensional schematic diagram of the composite beam of the present utility model after the longitudinal and transverse wet joints of the UHPC bridge deck are poured;

[0032] Figure 4 is a three-dimensional schematic diagram of the composite beam of the present utility model after the UHPC bridge deck is erected;

[0033] Figure 5 is a three-dimensional schematic diagram of the composite beam of the present utility model after the π-shaped high-strength steel and its shear keys are welded;

[0034] Figure 6 is a partial enlarged view of the UHPC bridge deck of the composite beam of the present utility model;

[0035] Figure 7 is a partial enlarged view of the steel internal brace of the composite beam of the present utility model;

[0036] Figure 8 is a partial enlarged view of the transverse connection groove and its shear key of the composite beam of the present utility model;

[0037] In the figure, 1. π-shaped high-strength steel; 2. steel diagonal brace; 3. steel internal brace; 4. asphalt concrete paving layer; 5. waterproof bonding layer; 6. UHPC bridge deck; 7. shear key; 8. longitudinal and transverse wet joints; 9. transverse connection groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model; obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0039] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0040] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "provided with", "sheathed / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0041] As Figure 1-8 shown, the present utility model provides a π-shaped high-strength steel 1-UHPC composite unit, including:

[0042] A π-shaped high-strength steel 1, with a steel inner brace provided in the middle and a steel diagonal brace 2 provided on the outside. Among them, the steel diagonal brace 2 and the steel inner brace 3 are preferably located at the same cross-section, and the steel diagonal brace 2 and the steel inner brace 3 are preferably connected by welding.

[0043] The yield strength of the π-shaped high-strength steel 1 is preferably greater than 460 MPa, and it has the characteristics of high strength, good toughness, excellent mechanical and welding processing performance, etc.

[0044] The π-shaped high-strength steel 1 gets its name because its cross-section resembles the letter "π". Its structure consists of a surface and two legs. Preferably, there are serrated lace on both sides of the surface; the cross-sectional shape of the π-shaped high-strength steel 1 gives it a relatively high load-bearing capacity. Since the horizontal wing plate of the π-shaped high-strength steel 1 is relatively wide, it can withstand a large horizontal force. The vertical web can withstand vertical forces, making the π-shaped high-strength steel 1 have a relatively high overall load-bearing capacity. This enables the π-shaped high-strength steel 1 to fully meet the load-bearing requirements of building structures and provides a safe and reliable structural foundation.

[0045] The structural form of the π-shaped high-strength steel 1 gives it good seismic performance. The horizontal wing plate of the π-shaped high-strength steel 1 can effectively absorb seismic forces, disperse them to various parts of the structure, reduce the impact of earthquakes on the structure, and improve the overall seismic performance.

[0046] The π-shaped high-strength steel 1 has good plasticity and weldability. In architectural design, it is often necessary to cut and weld steel according to specific structural requirements. The π-shaped high-strength steel 1 has good plasticity, can withstand a certain degree of stretching and impact, and is not easily broken. At the same time, due to the relatively simple structural form of the π-shaped high-strength steel 1, it is also convenient for welding operations. This makes the processing and installation of the π-shaped high-strength steel 1 in architectural design more convenient and improves the construction efficiency.

[0047] The π-shaped high-strength steel 1 also has good sustainability. With the continuous improvement of global environmental protection awareness, the construction industry has also put forward higher requirements for environmental protection. The π-shaped high-strength steel 1 is a recyclable building material, and the reuse of materials can be realized in design and construction, reducing waste of resources and having good sustainability.

[0048] The UHPC bridge deck 6 is laid on the two webs of the π-shaped high-strength steel 1 and the steel internal bracing 3. Each UHPC bridge deck 6 forms an integral whole by casting UHPC at the longitudinal and transverse wet joints, and the reinforcement ratio therein is preferably 1.5% - 3.0%; among them, the UHPC bridge deck 6 is a bridge deck made of ultra-high performance concrete (Ultra-High Performance Concrete, abbreviated as UHPC). UHPC is a concrete material with extremely high strength and durability, and its strength and durability far exceed those of traditional concrete. The characteristics of the UHPC bridge deck 6 include:

[0049] High strength: The strength of the UHPC bridge deck far exceeds that of the traditional concrete bridge deck, and it can bear greater loads and resist fatigue.

[0050] Thin and light design: Adopting a thin and light structural design, it is thinner than the traditional concrete bridge deck, saving material use and effectively reducing the impact of self-weight on the bridge structure.

[0051] Corrosion resistance: High-performance powder materials and special admixtures are used in UHPC, making the UHPC bridge deck have strong corrosion resistance, and it can effectively resist erosion factors such as acid-base attacks and chloride ion intrusion, extending the service life of the bridge.

[0052] Durability and aesthetics: Due to its excellent durability and aesthetics, the UHPC board has become a popular choice in the modern construction industry and is widely used in various building structures.

[0053] Cracking resistance and wear resistance: UHPC panels are renowned for their excellent cracking resistance and outstanding wear resistance. Additionally, the application of UHPC bridge deck 6 not only enhances the load-bearing capacity and durability of bridges but also shows potential in repairing in-service bridges, especially in situations where rapid traffic restoration is required.

[0054] UHPC uses modified reactive powder concrete doped with high-strength steel fibers of different sizes and / or shapes. As a cement-based composite material with ultra-high strength, ultra-high toughness, and high durability, UHPC is one of the most innovative engineering materials in the past three decades, achieving a huge leap in the performance of engineering materials. Modified reactive powder concrete is a major material of UHPC, mainly including graded quartz fine sand, cement, quartz powder, silica fume, high-range water reducer, and steel fibers, with a maximum aggregate size of 600μm. By increasing the fineness and activity of the mixture, the best strength and durability are expected to be obtained. The addition of steel fibers can effectively improve the mechanical properties and durability of concrete, thus obtaining fiber concrete with high strength, high toughness, and high durability. At the same time, it can also effectively hinder the expansion of microcracks inside the concrete, making it exhibit good plastic characteristics. Compared with ordinary concrete, UHPC has ultra-high tensile and compressive strengths, ultra-high toughness, high durability, low shrinkage creep, and excellent workability. By increasing the fineness and activity of the mixture, the best strength and durability are expected to be obtained. The steel fibers inside it can effectively improve the mechanical properties and durability of concrete, thus obtaining fiber concrete with high strength, high toughness, and high durability. At the same time, it can also effectively hinder the expansion of microcracks inside the concrete, making it exhibit good plastic characteristics.

[0055] A waterproof bonding layer 5, which is laid on the UHPC bridge deck 6;

[0056] An asphalt concrete paving layer 4, which is laid on the waterproof bonding layer 5.

[0057] In the present utility model, it further includes:

[0058] Shear keys 7, which are arranged in the longitudinal and transverse wet joints 8, steel internal braces 3, and flange transverse connection grooves 9 of the UHPC bridge deck 6. Among them, the shear keys 7 are preferably welded into the above-mentioned components. The shear keys 7 arranged on the longitudinal and transverse wet joints 8 and the steel internal braces 3 are preferably stud shear keys 7. The inner side walls of the transverse connection grooves 9 are preferably welded with stud shear keys 7 and channel steel shear keys 7 with alternately arranged notches in the middle.

[0059] In the present utility model, the steel mesh of the UHPC bridge deck 6 is arranged between the shear keys 7.

[0060] In the present utility model, the width of the longitudinal and transverse wet joints is between 50 and 100 cm.

[0061] In the present utility model, the steel diagonal bracing 2 and the steel internal bracing 3 are arranged within the range of 1 / 3 to 1 / 2 of the web height of the π-shaped high-strength steel 1, with a thickness of more than 20 cm and a longitudinal bridge spacing of 5 to 7 m.

[0062] In the present utility model, the steel diagonal bracing 2 has a rectangular solid cross-section, and the steel internal bracing 3 adopts a Γ-shaped cross-section at the end and a T-shaped cross-section at the mid-span.

[0063] On the other hand, the present utility model also provides a π-shaped high-strength steel 1-UHPC composite beam, which is formed by connecting a plurality of the above-mentioned π-shaped high-strength steel 1-UHPC composite units in series and in parallel.

[0064] In the present utility model, a plurality of the π-shaped high-strength steels 1 are fixedly connected at the transverse connection grooves 9 on the flanges of the π-shaped high-strength steel 1. Specifically, it can be:

[0065] Adjacent π-shaped high-strength steels 1 are welded within the transverse connection grooves 9 on their flanges, stud shear keys 7 are arranged on the inner walls, and channel steel shear keys 7 are arranged alternately in the middle of the transverse connection grooves 9, and consolidation is formed by cast-in-place UHPC material.

[0066] The above-mentioned π-shaped high-strength steel 1-UHPC composite beam structure provided by the present utility model can not only overcome the problems of fatigue cracking of the orthotropic steel bridge deck and damage of the paving layer of long-span bridges, but also give full play to the super compressive performance of UHPC material and the ultra-high tensile performance of high-strength steel. This composite beam structure gives full play to the mechanical properties of high-strength steel and UHPC material, and has the advantages of good durability, light structure, excellent mechanical properties, high bearing capacity, convenient construction, etc., and is especially suitable for bridge projects with large and medium spans.

[0067] The composite beam provided by the present utility model can solve the problems of fatigue cracks in the steel bridge deck and easy damage of its paving layer, as well as the problems of large self-weight of ordinary concrete in existing steel-concrete composite beams, brittle failure characteristics of concrete itself and its performance degradation under specific environments. It fully realizes the ultra-high compressive performance of UHPC and the ultra-high tensile performance of high-strength steel. When applied to the upper structure of a bridge, it can not only maximize the excellent mechanical properties of the materials, but also realize the lightening of the structure; in addition, the π-shaped high-strength steel 1, steel cross bracing, steel internal bracing 3 and shear keys 7 of the composite beam of the present utility model can all be prefabricated and welded in the factory, and the UHPC bridge deck 6 can be precast and poured on the construction site, which can realize the standardization, factoryization and scale of components and shorten the construction period; furthermore, the composite beam and its construction method of the present utility model have the advantages of "green, environmental protection, light, high strength, economical", with high comprehensive social benefits, and are especially suitable for large-scale applications of large and medium-span bridges.

[0068] The present utility model also provides a construction method for a π-shaped high-strength steel 1-UHPC composite beam, which includes the following steps:

[0069] First step: Prefabricate the π-shaped high-strength steel 1 in the factory, complete the welding of the steel diagonal brace 2 and the steel internal brace 3, and the welding of the shear keys 7 at the longitudinal and transverse wet joints and on the steel internal brace 3, and transport them to the construction site;

[0070] Second step: Erection the π-shaped high-strength steel 1 on site, weld the transverse connection grooves 9 and their shear keys 7 at the flanges of adjacent π-shaped high-strength steels 1, hoist and place the UHPC bridge deck 6 on the two webs of the π-shaped high-strength steel 1 and the steel internal brace 3, and arrange the steel mesh of the UHPC bridge deck 6 between the shear keys 7;

[0071] Third step: Make good sealing treatment to prevent slurry leakage, and use UHPC material to cast the longitudinal and transverse wet joints 8 and the transverse connection grooves 9 on site;

[0072] Fourth step: Lay the waterproof bonding layer 5 and the asphalt concrete pavement layer 4, and thus complete the construction of the π-shaped high-strength steel 1-UHPC composite beam structure.

[0073] The π-shaped high-strength steel 1, the steel cross brace, the steel internal brace 3 and the shear key 7 can all be prefabricated and welded in the factory, and the UHPC bridge deck 6 can be precast and cast on site, which can realize the standardization, industrialization and scale of components, and shorten the construction period.

[0074] The above is only the preferred specific implementation mode of the present utility model; however, the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution of the present utility model and its improved concept, makes equivalent substitution or change, and should be covered by the protection scope of the present utility model.

Claims

1. A π-shaped high-strength steel-UHPC composite unit, characterized in that, Including: A π-shaped high-strength steel with a steel internal brace provided in the middle and steel diagonal braces provided on the outside; A UHPC bridge deck laid on the two webs of the π-shaped high-strength steel and the steel internal brace; A waterproof bonding layer laid on the UHPC bridge deck; An asphalt concrete paving layer laid on the waterproof bonding layer.

2. The π-shaped high-strength steel-UHPC composite unit according to claim 1, characterized in that Also including: Shear keys provided in the longitudinal and transverse wet joints of the UHPC bridge deck, the steel internal brace, and the flange transverse connection grooves of the UHPC bridge deck.

3. The π-shaped high-strength steel-UHPC composite unit according to claim 2, wherein The steel mesh of the UHPC bridge deck is arranged between the shear keys.

4. A π-shaped high-strength steel-UHPC composite unit according to claim 2, characterized in that The width of the longitudinal and transverse wet joints is between 50 and 100 cm.

5. A π-shaped high-strength steel-UHPC composite unit according to claim 1, characterized in that The steel diagonal braces and the steel internal braces are located at the same cross-section.

6. The π-shaped high-strength steel-UHPC composite unit according to claim 5, characterized in that, The steel diagonal braces and the steel internal braces are arranged within the range of 1 / 3 to 1 / 2 of the web height of the π-shaped high-strength steel, with a thickness of more than 20 cm and a longitudinal bridge spacing of 5 to 7 m.

7. A π-type high-strength steel-UHPC composite unit according to claim 2, characterized in that, The shear keys provided on the longitudinal and transverse wet joints and the steel internal braces are stud shear keys.

8. A π-shaped high-strength steel-UHPC composite unit according to any one of claims 1-7, characterized in that, The steel diagonal braces are of rectangular solid cross-section, and the steel internal braces adopt a Γ-shaped cross-section at the ends and a T-shaped cross-section at the mid-span.

9. A π-shaped high-strength steel-UHPC composite beam, characterized in that, It is formed by connecting in series and parallel a number of π-shaped high-strength steel-UHPC composite units described in any one of claims 1-8.

10. A π-shaped high-strength steel-UHPC composite beam according to claim 9, characterized in that, A number of the π-shaped high-strength steels are fixedly connected at the transverse connection grooves of the flanges of the π-shaped high-strength steel.

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