Large double-layer UHPC-iron-based SMA thin-walled box type floating body structure and process

Abstract

This application relates to a large-scale double-layer UHPC-iron-based SMA thin-walled box-type floating structure and its process, belonging to the field of marine thin-walled floating structure design technology. It includes a bottom plate and side plates, with the side plates arranged around the bottom plate. Both the bottom plate and side plates include an outer thin shell, an iron-based SMA grid, lightweight blocks, and an inner thin shell. Both the outer and inner thin shells are cast from UHPC. The iron-based SMA grid is laid inside the outer thin shell, and connection areas are formed between the outer and inner thin shells. Several lightweight blocks are provided and distributed within the connection areas. Bottom ribs are cast from UHPC within the connection areas of the bottom plate, and interlayer ribs are cast from UHPC within the connection areas of the side plates. This floating structure has advantages such as simple process, convenient prestressing, and no friction loss. While improving the compressive, tensile, and impermeability resistance of the floating structure, it can also support the design of complex curved thin-walled floating structures.

Description

Technical Field

[0001] This invention relates to the field of marine thin-walled floating structure design technology, specifically to a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure. Background Technology

[0002] The continued advancement of global industrialization has led to a scarcity and even depletion of land resources, drawing attention to the oceans, which cover approximately 71% of the Earth's surface. As times have progressed, environmental protection has gained increasing importance worldwide, slowing down the traditional land reclamation and development of the ocean. Some countries have even implemented policies to restore the ecological environment by returning beaches to their original state. Amidst this conflict between marine development and environmental protection, large / very large floating structures (LFS / VLFS) have gained increasing attention from engineers. Compared to traditional land reclamation, LFS / VLFS offer advantages such as simplicity, ease of dismantling, minimal environmental impact, and full utilization of internal space.

[0003] However, as a load-bearing structure on water, its requirements for crack resistance, load-bearing capacity, and corrosion resistance are far higher than those for land structures. Traditional reinforced concrete structures cannot meet the large-size, high-performance requirements of box-type LFS / VLFS. While floating structures made of steel are lightweight and high-strength, they have poor corrosion resistance and high maintenance costs.

[0004] As a material that has experienced rapid development in the field of civil engineering in recent decades, ultra-high performance concrete (UHPC) possesses far superior compressive and tensile strength and corrosion resistance compared to traditional concrete. It is commonly used in structures such as long-span highway and railway bridges, thin-walled silos, and nuclear waste containers. The superior performance of UHPC aligns perfectly with the requirements of thin-walled structures, high impermeability and crack resistance, and high load-bearing capacity for low-lying solids (LFS) / vessel-low-lying solids (VLFS). Furthermore, its crack resistance and impermeability can be further improved through internal tensioning. However, traditional prestressed tensioning technology, when applied to thin-walled structures, presents significant construction challenges due to the large anchorages and tensioning machinery required. Additionally, its application in often polygonal floating structures results in substantial frictional losses. Summary of the Invention

[0005] This invention provides a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure, including a bottom plate and side plates, wherein the side plates are arranged around the bottom plate;

[0007] The base plate and side plate each include an outer thin shell, an iron-based SMA grid, lightweight blocks, and an inner thin shell. The outer thin shell and the inner thin shell are both cast from UHPC. The iron-based SMA grid is laid inside the outer thin shell. A connection area is formed between the outer thin shell and the inner thin shell. Several lightweight blocks are provided and distributed in the connection area.

[0008] The bottom plate has bottom ribs cast in the connection area by UHPC, and the side plate has interlayer ribs cast in the connection area by UHPC.

[0009] The lightweight block divides the connecting area into several interconnected channels, and the bottom rib beams and the interlayer rib beams extend and are distributed along their respective channels.

[0010] Both the bottom ribs and the interlayer ribs are grid-like.

[0011] The inner thin shell is thicker than the outer thin shell.

[0012] The lightweight block material is aluminum foam, gypsum, or foam.

[0013] A humidity sensor and a crack detection sensor are installed on the inner wall of the outer thin shell.

[0014] Both the humidity sensor and the crack detection sensor are located inside the lightweight block.

[0015] A process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure includes the following steps:

[0016] S1. Pre-stretch the iron-based SMA reinforcement and weave it into an iron-based SMA mesh.

[0017] S2. Place the iron-based SMA grid in the casting template and fix it in the predetermined position. Then, use UHPC grout to cast the outer thin shell. After the outer thin shell has initially set, attach several humidity sensors and crack detection sensors to its surface. Place and initially fix the lightweight block with colloid.

[0018] S3. UHPC grout is used to cast the bottom rib beams within the channel enclosed by lightweight blocks, and UHPC grout is used to cast the inner bottom plate at the same time to complete the casting of the bottom plate of the box-type floating structure.

[0019] S4. After the base plate has initially set, the formwork is erected and the side plates are poured. A pre-stretched iron-based SMA grid is placed in the formwork and fixed. Lightweight blocks are placed in the formwork to locate the interlayer ribs and the dimensions of the outer and inner thin shells. At the same time, several humidity sensors and crack detection sensors are placed in the formwork space. UHPC grout is injected into the formwork.

[0020] S5. After the side panels are poured, use a movable drying and curing chamber to cover the entire box-shaped floating structure and carry out dry heat curing at 200-250℃ for 2-3 days. After the dry heat curing is completed, carry out room temperature curing.

[0021] In step S4, the side plates are cast in layers using the slipform method.

[0022] During the layered casting process of the side panels, after the first layer is cast, the surface of the layer needs to be roughened.

[0023] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0024] 1. The UHPC-iron-based SMA mesh combination structure is adopted. The internal iron-based SMA mesh is heated and excited during the dry heat curing process. After cooling, permanent prestress can be applied to the UHPC matrix without tensioning or anchoring.

[0025] 2. The prestress of the iron-based SMA mesh is generated by the metallographic transformation of the iron-based SMA. The prestress is uniform along the length of the iron-based SMA, which solves the problem that traditional prestressing tendons will generate radial compressive force on the structure after bending at a large angle, resulting in prestress friction loss.

[0026] 3. The structure adopts a combination of outer and inner thin shells. When subjected to external water pressure, the outer thin shell, which is the first to be stressed, transfers the load to the inner shell through ribs. The internal stress is clear and the inner and outer layers work together to increase the overall load-bearing capacity of the structure.

[0027] 4. The lightweight floats within the inner cavity further increase the structure's buoyancy and reduce draft, while the multi-layered structure is more conducive to seepage prevention. Internally installed sensors can monitor the structure's health status at any time. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a schematic diagram illustrating that the outer contour of the floating structure is a regular shape according to the present invention;

[0031] Figure 3 This is a schematic diagram illustrating that the outer contour of the floating structure is a free-form surface, as described in this invention.

[0032] Figure 4 This is a schematic diagram illustrating the side plate sliding membrane construction method of the present invention.

[0033] In the diagram: 1. Outer thin shell; 2. Iron-based SMA mesh; 3. Inner thin shell; 4. Interlayer ribs; 5. Bottom ribs; 6. Lightweight block; 7. Humidity sensor; 8. Crack detection sensor; 9. Steel formwork; 101. Base plate; 102. Side plate. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of the present invention.

[0035] like Figure 1 and Figure 2 As shown, a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure of the present invention includes a bottom plate 101 and a side plate 102, with the side plate 102 arranged around the bottom plate 101.

[0036] Both the base plate 101 and the side plate 102 include an outer thin shell 1, an iron-based SMA grid 2, a lightweight block 6, and an inner thin shell 3. The outer thin shell 1 and the inner thin shell 3 are both cast from UHPC, and the thickness of the inner thin shell 3 is greater than that of the outer thin shell 1.

[0037] The iron-based SMA mesh 2 is laid inside the outer thin shell 1. The iron-based SMA mesh 2 is constructed using iron-based shape memory alloy (Fe-SMA) as reinforcement. Fe-SMA has excellent shape memory effect. The iron-based SMA mesh 2 is coupled with the outer thin shell 1 cast by UHPC. After the Fe-SMA material is heated and excited, it can be cooled to introduce the recovery stress generated into the structure. This recovery stress is also called self-prestress.

[0038] like Figure 1 and Figure 2 As shown, a connecting area is formed between the outer thin shell 1 and the inner thin shell 3. Several lightweight blocks 6 are provided and distributed within the connecting area. The two ends of each lightweight block 6 are connected to the outer thin shell 1 and the inner thin shell 3, respectively. Each lightweight block 6 divides the connecting area into several interconnected channels in a grid pattern. The lightweight blocks 6 are made of lightweight, porous materials with good water absorption, such as aluminum foam, foam, or gypsum, which increases the buoyancy of the floating structure while reducing the draft.

[0039] Bottom ribs 5 are cast in the channel of the base plate 101 through UHPC, and interlayer ribs 4 are cast in the channel of the side plate 102 through UHPC. Both bottom ribs 5 and interlayer ribs 4 extend along their respective channels, that is, both are in a grid pattern.

[0040] Both the base plate 101 and the side plate 102 adopt a double-layer structure consisting of an outer thin shell 1 and an inner thin shell 3. When the outer thin shell 1 of the side plate 102 is subjected to external water pressure, the load can be further transferred to the inner thin shell 3 through the interlayer rib beam 4, ensuring that the outer thin shell 1 and the inner thin shell 3 share the load together. The force transmission method of the base plate 101 under water pressure is the same as that of the side plate 102.

[0041] like Figure 1 and Figure 2 As shown, several humidity sensors 7 and crack detection sensors 8 are attached inside the outer thin shell 1 to monitor whether water seepage occurs inside the floating structure. The humidity sensors 7 and crack detection sensors 8 are both located inside the lightweight block 6, which can protect the sensors.

[0042] like Figure 1 and Figure 3 As shown, the overall outer contour of the floating structure can be a regular shape or a free-form surface.

[0043] The implementation principle of a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure: using UHPC material and iron-based SMA mesh 2, the iron-based SMA mesh 2 generates prestress without the need for tensioning through anchors, and the prestress is generated by metallographic transformation, so there is no prestress friction loss, which can overcome the shortcomings of traditional prestressing technology in LFS / VLFS.

[0044] In actual production and processing, the entire floating structure requires dry heat curing after casting. The high ambient temperature during dry heat curing of UHPC activates the shape memory effect of the iron-based SMA mesh 2 within the outer thin shell 1, causing prestress in the iron-based SMA mesh 2 without further processing. Besides dry heat curing, electrical excitation points can be pre-reserved on the floating structure to excite the iron-based SMA mesh 2 with electricity, or infrared equipment can be used to heat the surface of the UHPC, thus raising the temperature of the internal iron-based SMA mesh 2.

[0045] Furthermore, all iron-based SMA used undergoes pre-stretching treatment before being fabricated into a mesh. This pre-stretching process involves stretching the iron-based SMA during factory production to the required dimensions, followed by cutting as needed for ease of use. After dry heat curing and cooling, the iron-based SMA mesh 2 shrinks back, but this shrinkage is limited by the UHPC, thus providing circumferential stress to the outer thin shell 1. Under the action of this circumferential stress, the crack resistance of the outer thin shell 1 is significantly improved.

[0046] Compared to traditional prestressed tensioning technology, which suffers from frictional loss at any corner, the structure of UHPC material and iron-based SMA mesh 2 fully utilizes the high compressive, tensile, and impermeability properties of UHPC and the advantages of iron-based SMA, which has no prestressed frictional loss and requires no additional anchors or tensioning equipment. This satisfies the design requirements of free-form thin-walled floating structures and can improve the impermeability, crack resistance, and durability of box-type floating structures in marine environments.

[0047] like Figure 4 As shown, a process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure includes the following steps: S1, pre-stretching the iron-based SMA ribs and weaving them into an iron-based SMA mesh 2, wherein the pre-stretching process involves stretching the iron-based SMA to a specified size and then cutting it.

[0048] S2. Place the iron-based SMA grid 2 in the casting template and fix it in the predetermined position. Then, use UHPC grout to cast the outer thin shell 1. After the outer thin shell 1 has initially set, attach several humidity sensors 7 and crack detection sensors 8 to its surface. Place and preliminarily fix the lightweight block 6 with colloid.

[0049] S3. UHPC grout is used to cast the bottom rib beam 5 within the channel formed by the lightweight block 6, and UHPC grout is used to cast the inner bottom plate 101 at the same time, thus completing the casting of the bottom plate 101 of the box-type floating structure.

[0050] S4. After the base slab 101 has initially set, the side slab 102 is poured using the slipform method. Simultaneously, the outer thin shell 1, inner thin shell 3, and interlayer ribs 4 are poured in layers. A pre-stretched iron-based SMA mesh 2 is placed and fixed within the steel formwork 9. Lightweight blocks 6 are placed within the formwork to position the interlayer ribs 4 and the dimensions of the outer and inner thin shells 1 and 3. Several humidity sensors 7 and crack detection sensors 8 are placed within the formwork space. UHPC grout is injected into the formwork. After the first layer of side slab 102 has initially set, its surface is roughened. The formwork is then raised, and the lightweight blocks 6 are fixed to begin pouring the next layer of side slab 102.

[0051] S5. After the side plate 102 is poured, use a movable drying and curing room to cover the entire box-shaped floating structure and carry out dry heat curing at 200-250℃ for 2-3 days. After the dry heat curing is completed, carry out room temperature curing.

[0052] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0053] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0054] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0055] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A process for a large-scale double-layer UHPC-iron-based SMA thin-walled box-type floating structure, characterized in that: A large double-layer UHPC-iron-based SMA thin-walled box-type floating structure includes a bottom plate (101) and a side plate (102), wherein the side plate (102) is arranged around the bottom plate (101); The base plate (101) and the side plate (102) each include an outer thin shell (1), an iron-based SMA grid (2), a lightweight block (6) and an inner thin shell (3). The outer thin shell (1) and the inner thin shell (3) are both cast by UHPC. The iron-based SMA grid (2) is laid inside the outer thin shell (1). A connection area is formed between the outer thin shell (1) and the inner thin shell (3). Several lightweight blocks (6) are provided and distributed in the connection area. The bottom rib beam (5) is cast using UHPC in the connection area of ​​the bottom plate (101), and the connection area of ​​the side plate (102) Interlayer ribs are cast within the domain using UHPC (4); The process for a large-scale double-layer UHPC-iron-based SMA thin-walled box-type floating structure includes the following steps: S1. Pre-stretch the iron-based SMA reinforcement and weave it into an iron-based SMA mesh. S2. Place the iron-based SMA grid in the casting template and fix it in the predetermined position. Then, use UHPC grout to cast the outer thin shell. After the outer thin shell has initially set, attach several humidity sensors and crack detection sensors to its surface. Place and initially fix the lightweight block with colloid. S3. UHPC grout is used to cast the bottom rib beams within the channel enclosed by lightweight blocks, and UHPC grout is used to cast the inner thin shell to complete the casting of the bottom plate of the box-type floating structure. S4. After the base plate has initially set, the formwork is erected and the side plates are poured. A pre-stretched iron-based SMA grid is placed in the formwork and fixed. Lightweight blocks are placed in the formwork to locate the interlayer ribs and the dimensions of the outer and inner thin shells. At the same time, several humidity sensors and crack detection sensors are placed in the formwork space. UHPC grout is injected into the formwork. S5. After the side panels are poured, use a movable drying and curing chamber to cover the entire box-shaped floating structure and carry out dry heat curing at 200-250℃ for 2-3 days. After the dry heat curing is completed, carry out room temperature curing.

2. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, In step S4, the side plates are cast in layers using the slipform method.

3. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 2, characterized in that, During the layered casting process of the side panels, after the first layer is cast, the surface of the layer needs to be roughened.

4. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, The lightweight block (6) divides the connecting area into several interconnected channels, and the bottom rib beam (5) and the interlayer rib beam (4) extend along their respective channels.

5. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, Both the bottom rib (5) and the interlayer rib (4) are grid-like.

6. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, The inner thin shell (3) is thicker than the outer thin shell (1).

7. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, The lightweight block (6) is made of aluminum foam, gypsum or foam.

8. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 1, characterized in that, A humidity sensor (7) and a crack detection sensor (8) are installed on the inner wall of the outer thin shell (1).

9. The process for a large double-layer UHPC-iron-based SMA thin-walled box-type floating structure according to claim 8, characterized in that, The humidity sensor (7) and the crack detection sensor (8) are both located inside the lightweight block (6).

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