High-performance UHPC-ECCT type hybrid beam structure

Abstract

The utility model discloses a high-performance UHPC-ECCT type hybrid beam structure. The high-performance UHPC-ECCT type hybrid beam structure comprises an ECC section and a UHPC section located above the ECC section. Steel bar frameworks are poured in the ECC sections and the UHPC sections. The ECC section and the UHPC section are connected through a steel reinforcement framework and are poured into an integrated structure; the ECC section and the UHPC section are combined to form a T-shaped structure; according to the composite beam structure, the ultrahigh compressive property and the excellent durability of the UHPC material and the ultrahigh ductility, the crack resistance, the corrosion resistance and the like of the ECC material are fully exerted, the defects that a traditional concrete beam is large in dead weight, prone to cracking and poor in durability and corrosion resistance are overcome, the structural design is reasonable, and the composite beam structure is light and suitable for large-scale popularization and application. The bridge has the advantages of being good in durability, high in corrosion resistance, excellent in stress performance, high in bearing capacity, convenient and fast to construct and the like, and is particularly suitable for corrosion-resistant medium-and-small-span bridges in a coastal complex environment.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge structures, in particular to a high-performance UHPC-ECCT hybrid beam structure. Background Art

[0002] Currently, most bridge projects still rely on reinforced concrete beam structures. Such structures are subjected to various loads during service, such as self-weight, vehicle loads, and possible impact from falling rocks, and there is a risk of brittle failure. In severe cases, it may lead to the overall collapse of the superstructure of the bridge, causing casualties and economic losses. Compared with ordinary concrete, ultra-high performance concrete (UHPC) and engineered cementitious composite (ECC) exhibit significant advantages.

[0003] UHPC materials are known for their ultra-high compressive strength, good toughness, crack resistance, and durability, while ECC materials are attracting attention for their excellent ductility, high toughness, durability, corrosion resistance, and the characteristics of fine and dense crack development. Applying UHPC and ECC materials to the beam structures of bridge projects is expected to overcome problems such as brittle failure, easy cracking in the tension zone, and insufficient durability of ordinary reinforced concrete beams, significantly improving the bearing capacity, durability, and crack resistance of the beam structure, making them high-performance materials with broad application prospects.

[0004] Currently, the application of ECC materials in the beam structures of bridge projects is still in its infancy, and many researchers have begun to apply them to steel-concrete composite beams to enhance the strength and ductility of the structure. The application of UHPC materials in bridge projects is becoming increasingly widespread, covering key structures such as bridge decks and main girders. Especially in the application of bridge decks in steel-concrete composite structures, UHPC materials can effectively solve the problems of excessive self-weight of the bridge deck and cracking in the negative moment zone.

[0005] Compared with traditional steel-concrete composite beams, the structure using UHPC materials is not only superior in performance but also more reasonable in structural form, effectively solving the problem of cracking in the negative moment zone and improving the bearing capacity of the composite beam. In ordinary reinforced concrete T-beams, due to the relatively low compressive and tensile strengths of ordinary concrete, under the action of external loads, the upper edge of the T-beam bears compression and the lower edge bears tension. To better resist external loads, it is usually necessary to increase the upper edge section to enhance the bearing capacity, while the lower edge section is prone to cracking under service conditions, which not only affects the durability of the T-beam but also may lead to serious corrosion of the steel bars, reducing the structural safety. Therefore, optimizing bridge projects using UHPC and ECC materials is an inevitable choice to improve structural performance and ensure safety. Summary of the Utility Model

[0006] The purpose of the present utility model is to provide a high-performance UHPC-ECCT type hybrid beam structure to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above purpose, the present utility model provides the following solution:

[0008] A high-performance UHPC-ECCT type hybrid beam structure includes an ECC segment and a UHPC segment located above it;

[0009] The interior of the ECC segment and the UHPC segment is poured with a steel bar skeleton;

[0010] The ECC segment and the UHPC segment are connected through the steel bar skeleton and poured into an integral structure;

[0011] The ECC segment and the UHPC segment are combined to form a "T" shaped structure.

[0012] Further, the UHPC segment is a "T" shaped structure, and the ECC segment is a columnar structure with a narrower upper part and a wider lower part;

[0013] The upper half body and the lower half body of the steel bar skeleton are respectively adapted to the structural shapes of the UHPC segment and the ECC segment.

[0014] Further, the reinforcement ratio of the high-performance UHPC-ECCT type hybrid beam structure is 0.5% - 2.0%.

[0015] Further, the height of the ECC segment is 1 / 3 - 1 / 2 of the overall height of the high-performance UHPC-ECCT type hybrid beam structure.

[0016] Further, the connection surface between the ECC segment and the UHPC segment is a rough surface.

[0017] Further, the UHPC segment adopts modified reactive powder concrete, and the modified reactive powder concrete is reactive powder concrete doped with high-strength steel fibers of different sizes and / or shapes.

[0018] Further, the ECC segment adopts fiber-reinforced cementitious composite material, and the fiber-reinforced cementitious composite material is a cementitious composite material doped with polyethylene fibers of different diameters and / or lengths.

[0019] Further, the compressive strength of the UHPC segment > 150 MPa, and the tensile strength > 15 MPa.

[0020] Further, the ultimate tensile strain of the ECC segment > 3%, and the ultimate crack width < 100 μm.

[0021] As can be seen from the above technical solutions, compared with the prior art, the beneficial effects of the present utility model are as follows:

[0022] (1) The hybrid beam structure of the present utility model makes full use of the excellent properties of UHPC and ECC materials, demonstrates the advantages of material combination, and has excellent durability and corrosion resistance, excellent mechanical properties, extremely high load-bearing capacity, convenient construction and other advantages.

[0023] (2) The hybrid beam structure of the present utility model can solve the problems of heavy self-weight, poor durability, easy corrosion and easy cracking of traditional concrete beams.

[0024] (3) The hybrid beam structure of the present utility model fully combines the ultra-high compressive performance and excellent durability of UHPC, as well as the ultra-high ductility performance, crack resistance and corrosion resistance of ECC materials. When applied to the upper structure of a bridge, it can not only maximize the superior mechanical properties of the materials, but also achieve a lightweight design of the structure.

[0025] (4) The steel bar skeleton of the hybrid beam structure of the present utility model can be completed in a prefabrication yard set up in a factory or on site, and the hybrid beam can also be cast in a formwork in the prefabrication yard, so as to realize the standardized, factory-based and large-scale production of components, effectively shortening the construction period.

[0026] (5) The hybrid beam structure of the present utility model has the characteristics of reasonable and lightweight structure design, clear force-bearing, obvious advantages, etc., with significant comprehensive social benefits, and is particularly suitable for small and medium-span bridges with corrosion resistance in complex coastal environments. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure simulation effect of the high-performance UHPC-ECCT type hybrid beam structure in the embodiment of the present utility model;

[0029] Figure 2 It is a schematic diagram of the standard section simulation effect of the high-performance UHPC-ECCT type hybrid beam structure in the embodiment of the present utility model;

[0030] Figure 3 It is a schematic diagram of the structure simulation effect of the steel bar skeleton in the embodiment of the present utility model.

[0031] Description of the reference numerals:

[0032] 1. Steel reinforcement cage; 2. UHPC segment; 3. ECC segment; 4. Connection interface. Specific embodiments

[0033] The following will further describe in detail the specific embodiments of the present utility model in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present utility model, but not to limit the scope of the present utility model.

[0034] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application 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 application.

[0035] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "plurality" is two or more.

[0036] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0037] In order to better understand the purpose, structure and function of the present utility model, the following will further describe the present utility model in detail in conjunction with the drawings.

[0038] Embodiment

[0039] Refer to Figures 1-3 As shown, a high-performance UHPC-ECC type hybrid beam structure provided in this embodiment includes an ECC segment 3 and a UHPC segment 2 located above it;

[0040] The ECC segment 3 and the UHPC segment 2 are internally cast with a steel reinforcement cage 1;

[0041] The ECC segment 3 and the UHPC segment 2 are connected by the steel reinforcement cage 1 and cast into an integral structure.

[0042] The ECC segment 3 and the UHPC segment 2 are combined to form a "T" - shaped structure.

[0043] It should be noted that the UHPC segment 2 is a "T" - shaped structure, and the ECC segment 3 is a columnar structure with a narrower upper part and a wider lower part.

[0044] The upper part and the lower part of the steel reinforcement cage 1 are respectively adapted to the structural shapes of the UHPC segment 2 and the ECC segment 3. The upper part of the steel reinforcement cage 1 is cast inside the UHPC segment 2, and the lower part of the steel reinforcement cage 1 is cast inside the ECC segment 3.

[0045] Specifically, the T - shaped hybrid beam of the present utility model overcomes the problems of heavy self - weight, poor durability and easy cracking of traditional reinforced concrete beams. It efficiently integrates the ultra - high compressive strength and excellent durability of UHPC, as well as the ultra - high ductility, crack resistance and corrosion resistance of ECC. 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 lightweight design of the structure. In addition, the steel reinforcement cage 1 of the hybrid beam of the present utility model can be completed in a prefabrication yard set up in a factory or on - site, and the hybrid beam can also be cast by formwork in the prefabrication yard, which can realize the standardized, factory - based and large - scale production of components, effectively shortening the construction period. Moreover, the T - shaped hybrid beam of the present utility model and its construction method have the characteristics of reasonable structural design, light weight, clear force - bearing and obvious advantages, and are especially suitable for small and medium - span bridges with corrosion resistance in coastal complex environments.

[0046] It should be noted that in this embodiment, the UHPC segment 2 and the steel reinforcement cage 1 are cast to form the upper part of the hybrid beam, and the reinforcement ratio of the high - performance UHPC - ECC T - shaped hybrid beam structure is 0.5% - 2.0%.

[0047] The UHPC segment 2 uses modified reactive powder concrete, in which the mixture is doped with high - strength steel fibers of different sizes and / or shapes. The modified reactive powder concrete is mainly composed of graded quartz fine sand, cement, quartz powder, silica fume, high - range water - reducing agent and steel fibers, and the maximum aggregate size is 600μm. By improving the fineness and activity of the mixture, the best strength and durability can be achieved. The addition of steel fibers effectively improves the mechanical properties and durability of the concrete, thus realizing fiber concrete with high strength, high toughness and high durability, and at the same time effectively inhibiting the expansion of micro - cracks inside the concrete, showing good plastic properties. The compressive strength of the UHPC material is above 150MPa, and the tensile strength is above 15MPa.

[0048] In this embodiment, the joint surface between the UHPC segment 2 and the ECC segment 3 is defined as the connection interface 4. The connection interface 4 is a rough surface, that is, the joint surface between the ECC segment 3 and the UHPC segment 2 is a rough surface to enhance the connectivity.

[0049] The ECC segment 3 and the steel reinforcement cage 1 are cast to form the lower part of the hybrid beam. The height of the ECC segment 3 is 1 / 3 to 1 / 2 of the overall height of the high-performance UHPC-ECCT type hybrid beam structure, that is, the connection interface 4 is located at 1 / 3 to 1 / 2 of the beam height.

[0050] ECC is a new type of randomly distributed short fiber reinforced cement-based composite material with super toughness. Its main components include cement, fly ash, quartz sand, silica fume, water, water reducing agent and polyethylene fiber. This fiber reinforced cement-based composite material incorporates polyethylene fibers of different diameters and / or lengths, effectively improving the ductility, energy absorption capacity, corrosion resistance and impact resistance of concrete structures. The ultimate tensile strain of ECC can reach more than 3%, and the ultimate crack width is less than 100μm.

[0051] The T-shaped hybrid beam in this embodiment fully utilizes the utilization efficiency of UHPC materials and ECC materials, fully reflects the beneficial effects of material combination, and has the advantages of good durability, strong corrosion resistance, good mechanical properties, high load-bearing capacity and convenient construction.

[0052] Specifically, the construction method of the above-mentioned high-performance UHPC-ECCT type hybrid beam structure includes the following steps:

[0053] The first step: The steel reinforcement cage 1 is completed by binding in a prefabrication yard set up in the factory or on site;

[0054] The second step: The formwork is erected in the prefabrication yard, and the ECC segment 3 is poured to the connection interface 4, and the connection interface 4 is set as a rough surface;

[0055] The third step: After the ECC segment 3 solidifies, continue to pour the UHPC segment 2;

[0056] The fourth step: Steam curing for 28 days can complete the prefabrication construction of the UHPC-ECCT shaped hybrid beam and transport it to the construction site.

[0057] The steel reinforcement cage 1 of the T-shaped hybrid beam can be completed in a prefabrication yard set up in the factory or on site, and the hybrid beam can also be formwork-poured in the prefabrication yard, realizing the standardization, industrialization and scale of components, and significantly shortening the construction period.

[0058] In this text, specific examples are used to elaborate on the principle and implementation mode of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model; at the same time, for those of ordinary skill in the art, according to the idea of the present utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation on the present utility model.

Claims

1. A high-performance UHPC-ECCT hybrid beam structure, characterized in that, It includes an ECC section and a UHPC section located above it; A steel reinforcement cage is cast inside the ECC section and the UHPC section; The ECC section and the UHPC section are connected by the steel reinforcement cage and cast into an integral structure; The ECC section and the UHPC section are combined to form a "T" - shaped structure.

2. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The UHPC section is a "T" - shaped structure, and the ECC section is a columnar structure that is narrower at the top and wider at the bottom; The upper - half body and the lower - half body of the steel reinforcement cage are respectively adapted to the structural shapes of the UHPC section and the ECC section.

3. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The reinforcement ratio of the high - performance UHPC - ECC T - shaped hybrid beam structure is 0.5% - 2.0%.

4. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The height of the ECC section is 1 / 3 - 1 / 2 of the overall height of the high - performance UHPC - ECC T - shaped hybrid beam structure.

5. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The connection surface between the ECC section and the UHPC section is a rough surface.

6. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The UHPC section uses modified reactive powder concrete, and the modified reactive powder concrete is reactive powder concrete doped with high - strength steel fibers of different sizes and / or shapes.

7. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The ECC section uses fiber - reinforced cement - based composite material, and the fiber - reinforced cement - based composite material is a cement - based composite material doped with polyethylene fibers of different diameters and / or lengths.

8. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The compressive strength of the UHPC section > 150 MPa, and the tensile strength > 15 MPa.

9. The high-performance UHPC-ECCT hybrid beam structure according to claim 1, characterized in that, The ultimate tensile strain of the ECC section > 3%, and the ultimate crack width < 100 μm.

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