Spatial hyperboloid continuous bridge structure based on non-uniform layering process and construction method

Abstract

The application relates to a spatial double-curved continuous bridge structure based on a non-uniform layering process and a construction method, and the concrete 3D printing bridge body comprises a plurality of longitudinally closely arranged arch span units, the middle part of the arch span unit is downwardly bent in the transverse direction, the middle part of the arch span unit is upwardly bent in the longitudinal direction, the whole is a double-curved structure, and the top part is provided with a longitudinal groove; each arch span unit comprises a plurality of longitudinally closely arranged U-shaped segmented printing components, and the segmentation lines between the U-shaped segmented printing components are distributed in a radial manner in the longitudinal direction. The application designs and constructs a spatial double-curved continuous bridge, combines the free forming capacity of the concrete 3D printing technology and the stress advantage of the arch structure, introduces non-uniform layering slicing, path optimization and multi-degree-of-freedom printing and other technologies, and can ensure the stability of the printing process and the quality of the components; meanwhile, the non-uniform layering control technology is adopted, accurate printing of variable layer thickness can be realized, and the effective connection of the printing components and the foundation and the steel structure and the positioning and installation precision of the whole bridge are ensured.

Description

Technical Field

[0001] This invention relates to the field of 3D printing construction technology for irregular bridges, specifically to a spatial hyperboloid continuous bridge structure and construction method based on non-uniform layering technology. Background Technology

[0002] The application of 3D printing (additive manufacturing) technology in construction engineering is increasing, with 3D printing of municipal pedestrian bridges becoming a significant area of ​​research and development. Building bridges using 3D printing not only allows for complex and free-form structural designs, integrating artistic elements into functional facilities, transforming bridges from mere transportation structures into urban landscapes and landmarks, thus enhancing the overall image of the city; it also saves on the costs of traditional formwork construction and accelerates construction speed. For example, several demonstration projects of 3D-printed bridges have emerged both domestically and internationally, including Europe's first 3D-printed concrete pedestrian bridge and the 20-meter span 3D-printed unreinforced arch bridge in the Shaanxi Archaeological Park in my country, all showcasing the advantages of 3D printing in terms of the freedom of bridge design.

[0003] However, current 3D printing technology still faces many challenges in its practical application to irregularly shaped bridges. First, existing printing processes mostly employ a planar layer-by-layer stacking method, resulting in significant anisotropy in the structural direction, weak interlayer bonding, and significantly lower vertical tensile strength compared to in-plane performance, making it difficult to meet the overall load-bearing capacity and durability requirements of bridge structures. Second, in the printing of complex curved surfaces, the fixed-layer-thickness planar slicing method easily produces a noticeable step effect, resulting in rough component surfaces and stress concentration in areas of curvature change, affecting structural stability and appearance quality. Simultaneously, limited by the freedom of motion of traditional printing equipment, the printing path often cannot accurately conform to the complex geometry of three-dimensional space, leading to significant deviations between the actual structure and the design. Furthermore, most 3D-printed bridges currently are simple curved surfaces or single-span arch structures, lacking systematic solutions for structural continuity, spatial morphology, and bridge assembly processes. In particular, there is a lack of mature integrated methods for controlling the connection accuracy and error adjustment between printed components and the steel reinforcement frame and foundation structure, severely restricting the in-depth application and engineering promotion of 3D printing technology in complex irregularly shaped bridges.

[0004] Therefore, it is necessary to propose new measures to overcome the above-mentioned shortcomings. Summary of the Invention

[0005] The purpose of this invention is to provide a spatial hyperboloid continuous bridge structure and construction method based on non-uniform layering technology, so as to at least solve the problems of weak interlayer bonding, strong anisotropy, difficulty in forming complex curved surfaces, and inconvenience in on-site installation and connection of existing 3D printed concrete bridge technology.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A spatial hyperboloid continuous bridge structure based on non-uniform layering technology is provided. The spatial hyperboloid continuous bridge structure includes a concrete 3D printed bridge body. The concrete 3D printed bridge body includes multiple longitudinally closely arranged arch span units. The arch span units are bent downward in the middle of the transverse direction and bent upward in the middle of the longitudinal direction. The whole structure is a hyperboloid structure with a longitudinal groove at the top.

[0008] Each arch span unit includes multiple longitudinally closely arranged U-shaped segmented printed components, and the dividing lines between the U-shaped segmented printed components are distributed radially in the longitudinal direction.

[0009] Furthermore, multiple arch span units are longitudinally combined to form an arch-shaped whole, and the bottom of the joint between two longitudinally adjacent arch span units protrudes downward, serving as a support point for the lower bridge foundation.

[0010] Furthermore, the longitudinal width of the U-shaped segmented printed component gradually increases from the transverse center to both sides, and the thickness of the U-shaped segmented printed component gradually decreases from the transverse center to both sides.

[0011] Furthermore, the U-shaped segmented printed component has longitudinally arranged through holes inside;

[0012] The length of the through hole along the transverse structural direction of the U-shaped segmented printed component gradually decreases from the transverse center to both sides.

[0013] Furthermore, the spatial hyperboloid continuous bridge structure also includes concrete 3D-printed sidewalk slabs and a steel structure sidewalk support system;

[0014] The steel structure pedestrian walkway support system is located within the groove of the arched whole, and the concrete 3D printed pedestrian walkway slab is laid on top of the steel structure pedestrian walkway support system;

[0015] The lateral sides of the arch span unit are higher than the concrete 3D printed sidewalk slab, and the higher part serves as the handrails on both sides of the lateral sides of the spatial hyperboloid continuous bridge structure.

[0016] Furthermore, the steel structure pedestrian walkway support system includes columns, longitudinal main beams, and cross braces;

[0017] The bottom of the column passes through the 3D-printed concrete bridge body and is supported by the top of the bridge foundation. The longitudinal main beam and the cross brace are connected in a crisscross pattern.

[0018] Furthermore, the concrete 3D printed sidewalk slab includes multiple multi-layer printed irregular planar components, which are laid on top of the longitudinal main beam and the cross brace;

[0019] The lateral side edge shapes of the irregularly shaped planar printed component match the inner wall edge shapes of the handrail.

[0020] On the other hand, a method for constructing a spatial hyperboloid continuous bridge structure based on a non-uniform lamination process as described above is provided, the method comprising:

[0021] Establish a three-dimensional design model of a spatial hyperboloid continuous bridge structure;

[0022] The 3D-printed concrete bridge body is longitudinally divided into multiple arch span units;

[0023] An adaptive slicing method was used to longitudinally divide the arch span unit into multiple U-shaped segmented printed components;

[0024] Based on the longitudinal width difference of the U-shaped segmented printed components, non-uniform lamination process control calculations are performed to print U-shaped segmented printed components.

[0025] The U-shaped segmented printed components were transported to the site and assembled into an arch. Longitudinal steel bars were placed in the longitudinal through holes, and the U-shaped segmented printed components were connected by high-strength polymer mortar. Cement grout was then poured into the through holes.

[0026] A steel structure pedestrian walkway support system was installed inside the 3D-printed concrete bridge body, and 3D-printed concrete pedestrian walkway slabs were laid on top of the steel structure pedestrian walkway support system.

[0027] Furthermore, an adaptive slicing method is used to longitudinally divide the arch span unit into multiple U-shaped segmented printed components, including:

[0028] Extract the arch axis of each arch span element and establish multiple normal surfaces on the arch axis;

[0029] Cut along the normal plane of the arch span unit to form a printable U-shaped segmented printed component;

[0030] Extract the starting and ending surfaces of the U-shaped segmented printed component. Both surfaces are normal tangents to the arch axis and are not parallel.

[0031] Non-uniform layer thickness slicing is performed on the U-shaped segmented printed component from the starting face to the ending face.

[0032] Furthermore, based on the longitudinal width difference of the U-shaped segmented printed components, non-uniform lamination process control calculations are performed to print the U-shaped segmented printed components, including:

[0033] Extracting key curved points from the surface of a 3D-printed concrete bridge;

[0034] Discretize the curve path between each pair of adjacent key points at equal distances, and insert uniform path points between each segment to form a path point sequence;

[0035] Obtain the geometric curvature data of the 3D design model of the concrete 3D printed bridge body, and set the reference layer thickness and reference printing speed;

[0036] The layer thickness at each path point sequence is determined based on the local radius of curvature of the concrete 3D printed bridge body surface.

[0037] Calculate the speed of the printing equipment at each position based on the layer thickness;

[0038] The movement speed of the device is adjusted according to the movement speed to ensure that the amount of extruded material matches the movement speed in real time and to maintain uniform material accumulation.

[0039] The motion speed data is interpolated to the corresponding path point to form a code that the path execution device can recognize. The moving speed of the path execution device is adjusted according to the motion speed to ensure that the amount of extruded material matches the motion speed in real time and to keep the material piled up evenly.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] This invention provides a spatial hyperboloid continuous bridge structure and construction method based on a non-uniform layering process. It designs and constructs a spatial hyperboloid continuous bridge, combining the free-form capabilities of concrete 3D printing technology with the structural advantages of arch structures. By introducing technologies such as non-uniform layering slicing, path optimization, and multi-degree-of-freedom printing, the stability of the printing process and the quality of the components can be ensured. Simultaneously, this invention employs non-uniform layering control technology, enabling precise printing with varying layer thicknesses, guaranteeing effective connections between printed components and the foundation and steel structure, and ensuring the overall positioning and installation accuracy of the bridge. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of a spatial hyperboloid continuous bridge structure provided in an embodiment of the present invention.

[0044] Figure 2 This is a block diagram of a spatial hyperboloid continuous bridge structure provided in an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the segmented printing components of a spatial hyperboloid continuous bridge structure provided in an embodiment of the present invention.

[0046] Figure 4A schematic diagram of the segmented printing components of a spatial hyperboloid continuous bridge structure provided in an embodiment of the present invention.

[0047] Figure 5 This is a schematic diagram of the steel structure pedestrian support system for a spatial hyperboloid continuous bridge structure provided in an embodiment of the present invention.

[0048] The diagram is labeled as follows:

[0049] 1- Concrete 3D printed bridge body, 2- Concrete 3D printed sidewalk slab, 3- Steel structure sidewalk support system. Detailed Implementation

[0050] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0051] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "left", "right", "longitudinal", "lateral", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0054] In a specific implementation, the length direction of the bridge is... Figure 1 The direction from left to right is defined as the vertical direction, and the direction perpendicular to it is defined as the horizontal direction.

[0055] This invention provides a spatial hyperboloid continuous bridge structure based on a non-uniform layering process. According to the characteristics of concrete 3D printing and the stress requirements of the spatial hyperboloid continuous bridge structure, the bridge structure is creatively divided into components. Non-uniform layering control ensures the stability of the printing process and the quality of the components, and achieves precise printing with variable layer thickness.

[0056] Specifically, the spatial hyperboloid continuous bridge structure involved in this invention includes a 3D-printed concrete bridge body 1, a 3D-printed concrete pedestrian walkway slab 2, and a steel structure pedestrian walkway support system 3, which are assembled into an integral continuous bridge structure.

[0057] 1. 3D-printed concrete bridge body 1:

[0058] The 3D-printed concrete bridge body 1 comprises multiple longitudinally closely arranged arch span units. Each arch span unit curves downwards at its transverse midpoint and upwards at its longitudinal midpoint, forming a hyperboloid structure with a longitudinal groove at the top. Each arch span unit further comprises multiple longitudinally closely arranged U-shaped segmented printed components, with the dividing lines between these U-shaped segments radially distributed longitudinally. Multiple arch span units are longitudinally combined to form an arch-shaped whole. The bottom of the joint between two longitudinally adjacent arch span units protrudes downwards, serving as a support point for the lower bridge foundation.

[0059] The U-shaped segmented printed component has a longitudinal width that gradually increases from the transverse center to both sides, and a thickness that gradually decreases from the transverse center to both sides. The U-shaped segmented printed component has longitudinally arranged through holes inside, and the length of these through holes along the transverse structural direction of the U-shaped segmented printed component gradually decreases from the transverse center to both sides.

[0060] In some embodiments, the strip thickness of the U-shaped segmented printed component is non-uniform, with the thickness of the upper handrail area being twice the thickness of the lower pressure-bearing area. The outer shell of the U-shaped segmented printed component is a non-uniform laminated structure formed by layer-by-layer printing, and an adaptive slicing strategy is used to control the printing layer thickness in different areas. The single-layer thickness at the handrail position is twice the single-layer thickness at the bottom of the bridge deck.

[0061] During the printing process, U-shaped segmented printed components are intermittently placed with U-shaped steel mesh. When the components are assembled into bridge segments, longitudinal steel bars are placed through the longitudinal through holes and joined with high-strength polymer mortar. After the splicing is completed, high-flowability cement slurry is injected into the internal cavity for overall connection and reinforcement.

[0062] 2. Steel structure pedestrian walkway support system 3:

[0063] The steel structure pedestrian walkway support system 3 includes columns, longitudinal main beams, and cross braces. The bottom of the columns passes through the concrete 3D-printed bridge body 1 and is supported by the top of the bridge foundation. The longitudinal main beams are located at the top of the columns, and the cross braces are located at the top of the longitudinal main beams. The longitudinal main beams and cross braces are connected in a crisscross pattern.

[0064] Specifically, such as Figure 5 The bridge foundation has a mountain-shaped top, with the arch span units on both sides contacting the two sides of the mountain-shaped structure. The bottom of the columns is supported by the top of the mountain-shaped structure. The ends of the longitudinal main beams are supported to the top of the columns. The longitudinal main beams near the bridge centerline are straight, while the longitudinal main beams on both sides are curved, matching the shape of the inner walls of the arch span units on both sides.

[0065] 3. Concrete 3D printed sidewalk slab 2:

[0066] The 3D-printed concrete sidewalk slab 2 comprises multiple multi-layered, irregularly shaped planar printed components, laid on top of the longitudinal main beams and cross braces. Gaps are left between the irregularly shaped planar printed components and the bridge body on the cross braces.

[0067] The lateral edge shapes of the irregularly shaped planar printed components match the inner wall edge shapes of the handrail.

[0068] The steel structure pedestrian support system 3 is located within the recess of the arched structure, and the 3D-printed concrete pedestrian slab 2 is laid on top of the steel structure pedestrian support system 3. The lateral sides of the arch span unit are higher than the 3D-printed concrete pedestrian slab 2, and the higher parts serve as handrails on the lateral sides of the spatial hyperboloid continuous bridge structure.

[0069] The construction method of the above structure specifically includes the following steps:

[0070] S1: Establish a three-dimensional design model of the spatial hyperboloid continuous bridge structure.

[0071] S2: The 3D-printed concrete bridge body 1 is longitudinally divided into multiple arch span units.

[0072] S3: An adaptive slicing method is used to longitudinally divide the arch span unit into multiple U-shaped segmented printing components, determine the printing layer thickness of each U-shaped segmented printing component at different positions, and dynamically adjust the layer thickness according to the local curvature of the surface.

[0073] Specifically:

[0074] S31: Extract the arch axis of each arch span element and establish multiple normal surfaces on the arch axis;

[0075] S32: Cut along the normal plane of the arch span unit to form a printable U-shaped segmented printed component;

[0076] S33: Extract the starting and ending surfaces of the U-shaped segmented printed component. Both surfaces are normal tangents to the arch axis and are not parallel.

[0077] S34: Perform non-uniform layer thickness slicing on the U-shaped segmented printed component from the starting face to the ending face.

[0078] S4: Based on the longitudinal width difference of the U-shaped segmented printed components, non-uniform lamination process control calculations are performed. A multi-degree-of-freedom printing device is used to print the U-shaped segmented printed components layer by layer. During the printing process, U-shaped steel mesh is placed at predetermined positions.

[0079] Specifically:

[0080] S41: Extract key curved points from the surface of the 3D printed concrete bridge body 1;

[0081] S42: Discretize the curve path between each pair of adjacent key points at equal distances, and insert uniform path points between each segment to form a path point sequence;

[0082] S43: Obtain the geometric curvature data of the 3D design model of the concrete 3D printed bridge body 1, and set the reference layer thickness and reference printing speed;

[0083] S44: Determine the layer thickness at each path point sequence based on the local radius of curvature of the surface of the 3D-printed concrete bridge body 1;

[0084] S45: Calculate the speed of the printing equipment at each position based on the layer thickness;

[0085] S46: Adjust the moving speed of the path execution device according to the movement speed to ensure that the amount of extruded material matches the movement speed in real time and maintain uniform material accumulation;

[0086] S47: Interpolate the motion speed data to the corresponding path point to form a code that the path execution device can recognize. Adjust the moving speed of the path execution device according to the motion speed to ensure that the amount of extruded material matches the motion speed in real time and maintain uniform material accumulation.

[0087] S5: Transport the U-shaped segmented printed components to the site and assemble them into an arch. Arrange height-adjustable supports on the top surface of the bridge foundation. Adjust the height of the supports according to the designed arch curve. When assembling the U-shaped segmented printed components into an arch section, place longitudinal steel bars in the longitudinal through holes. Connect the U-shaped segmented printed components with high-strength polymer mortar, and then inject cement grout into the through holes.

[0088] S6: Install a steel structure pedestrian walkway support system 3 inside the concrete 3D printed bridge body 1, and lay a concrete 3D printed pedestrian walkway slab 2 on top of the steel structure pedestrian walkway support system 3.

[0089] Specifically, steel structure column anchors are pre-embedded in the bridge foundation, steel structure columns are installed and steel structure longitudinal beams and cross braces are welded, and rubber pads are placed between the sides of the cross braces and the printed components for cushioning; pedestrian walkways are placed on the steel structure cross braces of the pedestrian walkway support system, and a certain structural gap is left between the pedestrian walkways and the bridge body to prevent mutual constraint and deformation.

[0090] The spatial hyperboloid continuous bridge structure constructed by this invention utilizes an arch-shaped load-bearing system, allowing the 3D-printed concrete to primarily bear compressive stress, avoiding tensile stress on weak interlayer bonding surfaces, and significantly improving structural safety redundancy. The continuous bridge structure design interconnects multiple arch spans, enabling them to share loads collaboratively, resulting in better overall bridge stiffness and stability. Furthermore, the non-uniform layer slicing and path optimization techniques of this invention effectively reduce the step effect and texture defects in curved surface printing, improving surface smoothness; simultaneously, multi-degree-of-freedom motion control improves the interlayer bonding quality of materials and reduces anisotropy. This invention considers the entire process from printing to installation, offering strong operability. On-site installation uses adjustable supports to position and adjust the arches, eliminating manufacturing and installation errors, ensuring precise positioning of the bridge body and guaranteeing the quality of the completed bridge.

[0091] The structure and method provided by the present invention are further illustrated below through specific embodiments:

[0092] Example 1:

[0093] This embodiment provides a spatial hyperboloid continuous bridge structure, including a 3D-printed concrete bridge body 1, a 3D-printed concrete sidewalk slab 2, and a steel structure sidewalk support system 3.

[0094] The spatial hyperboloid continuous bridge structure has a total length of 30m and a mid-span height of 2.5m. The outer surface of the 3D-printed concrete bridge body 1 is arc-shaped and consists of 7 arch span unit structures, as shown below. Figure 2 As shown, the five central arch span units are each composed of five segmented printed components, while the two arch span units on both sides are each composed of three segmented printed components. The entire 3D printed concrete bridge body is composed of 31 U-shaped segmented printed components that are sequentially spliced ​​together along the longitudinal direction of the bridge span.

[0095] The U-shaped segmented printed component consists of a 3D-printed hollow concrete structure, a U-shaped steel mesh, and post-cast cement grout. A schematic diagram of the No. 15 3D-printed hollow concrete structure (the 15th U-shaped segmented printed component along the longitudinal length of the bridge) is shown below. Figure 4 As shown, each 3D-printed hollow concrete structure has 14 internal cavities to reduce its weight and facilitate the placement of longitudinal reinforcing bars. Preferably, the wall thickness and cavity width of the 3D-printed hollow concrete structure can vary along the height or length of the component to adapt to the stress requirements of different parts. For example, near the lower part of the bridge deck, due to stress concentration, the wall thickness of the arch block can be increased and the length of the internal cavities can be gradually reduced; in the upper handrail area of ​​the bridge deck, where the stress is relatively small, the wall thickness of the arch block can be relatively reduced and the internal cavities can be lengthened to reduce weight.

[0096] In this embodiment, the 3D printed hollow structure of concrete No. 15 has a printing height of approximately 1.5m, a width (distance between the outer edges of the two side walls) of approximately 3m, a wall thickness of 15cm in the upper handrail area with closed inner cavities at the edges (i.e., solid), and a wall thickness of approximately 30cm gradually transitions downwards along the arch block to the mid-span. Figure 3 As shown, the 3D-printed hollow concrete structure is a non-uniform layer-by-layer printing construction. The single-layer printing thickness of the handrail is 20mm, and that of the bottom of the bridge deck is 10mm. This non-uniform cross-section design ensures that the arch blocks have sufficient strength at critical stress points, while reducing weight in other parts, thus ensuring that the entire bridge is both safe and reliable and makes efficient use of materials.

[0097] In this embodiment, as Figure 1 As shown, the steel structure pedestrian walkway support system 3 consists of steel structure columns and steel structure longitudinal main beams and cross braces connected to the columns. The steel structure columns are made of seamless round tubing with a diameter of Φ133×6mm, the longitudinal main beams are made of square steel with a diameter of 100×100×6mm, and the cross braces are made of square steel with a diameter of 80×80×4mm.

[0098] The concrete 3D printed sidewalk slab 2 includes multiple irregularly shaped planar printed components. The concrete 3D printed sidewalk slab 2 is set on the steel structure beam with a gap between it and the bridge body. The concrete 3D printed sidewalk slab 2 is printed in a total of 5 layers. The layer height is 10mm near the centerline of the bridge and 20mm near the concrete 3D printed bridge body. This non-uniform printing design achieves the architectural texture design of the sidewalk slab, forming a wave-like shape.

[0099] Example 2:

[0100] This embodiment provides a construction method for the spatial hyperboloid continuous bridge structure in Embodiment 1, specifically including the following steps:

[0101] S1: Use computer-aided design software to create a 3D design model of the spatial hyperboloid continuous bridge structure. Computer-aided design software includes, but is not limited to, Autodesk Inventor, SolidWorks, CATIA, Pro / E, AutoCAD, UGNX, SolidEdge, and Rhino.

[0102] S2: Based on the length and foundation distribution of the spatial hyperboloid continuous bridge structure, the concrete 3D printed bridge body 1 is vertically divided into 7 arch span units along the longitudinal direction of the bridge (arch axis direction).

[0103] S3: An adaptive slicing method is used to divide each arch span unit into printable U-shaped arch segment components along the span direction. The five middle arch span units are each divided into five printable segments, and the two arch span units on both sides are divided into three printable segments. The single-layer printing thickness of the handrail part of the segmented printable component is set to 20mm, the bottom of the bridge deck is 10mm, and the layer thickness of other areas is a linear interpolation value.

[0104] This step specifically includes:

[0105] ① Extract the arch axis of each arch span unit, and establish 6 normal surfaces on the arch axis of the middle 5 arch span units according to the printing capability of the concrete 3D printing equipment, and establish 2 normal surfaces on the arch axis of the two arch span units on both sides.

[0106] ② Cut the reference normal plane of the arch span unit to form a printable arch segmented printing component. The five middle arch span units are divided into five segmented printing components, and the two arch span units on both sides are divided into three segmented printing components.

[0107] ③ Extract the starting surface (bottom surface) and ending surface (top surface) of the arched segmented printed component. Both surfaces are normal tangents of the axis and are not parallel.

[0108] ④ Based on the aforementioned non-parallel area between the bottom and top surfaces, perform non-uniform layer thickness slicing. Starting from the bottom surface, gradually slice along the axial direction to the top surface. Set the maximum slice thickness to 20mm and the minimum slice thickness to 10mm. The number of layers is adaptively adjusted according to the printing height of the segmented printed component and the slice thickness limitations. Figure 3 As shown, the total number of layers for segmented printing component No. 15 is 70.

[0109] S4: Based on the difference in layer thickness of the components, non-uniform lamination process control calculation is performed. The reference layer thickness H = 15mm and the reference printing speed V = 0.2m / s are set. The printing strip width is 35mm. A multi-degree-of-freedom printing device is used to print concrete 3D printing material layer by layer. During the printing process, a U-shaped steel mesh is placed every 9 layers.

[0110] This step specifically includes:

[0111] ① Extract the key points of the curved surface of the bridge body and mark them as K. i (i = 1, 2, 3, ..., n), for example, 95 key points of the curved surface were marked on the printing plane of the 15th segment printing component;

[0112] ② For each pair of adjacent key points K i and K i+1 The curved paths between them are discretized at equal intervals, and the length of each segment D is set to 3cm. Path points are inserted evenly between each segment to form a path point sequence.

[0113] ③ Obtain the geometric curvature data of the three-dimensional model of the bridge body, and set the reference layer thickness H = 15mm and the reference printing speed V = 0.2m / s;

[0114] ④ Determine the layer thickness h at each path point sequence based on the local radius of curvature R of the bridge surface. i ;

[0115] ⑤ Based on the determined layer thickness h i Calculate the speed v of the printing equipment at various positions. i The calculation formula is:

[0116] v i =h i ×(V / H)

[0117] ⑥ Based on the velocity v i Adjust the moving speed of the path execution device to ensure that the amount of extruded material matches the moving speed in real time, and keep the material piled up evenly.

[0118] ⑦ The speed of motion v i Data is interpolated to the corresponding path points to form code recognizable by the path execution device, based on the movement speed v. i Adjust the moving speed of the path execution device to ensure that the amount of extruded material matches the moving speed in real time, and keep the material piled up evenly.

[0119] S5: After the printed components have been cured to 90%, they are transported to the site. Height-adjustable supports are placed on the top surface of the bridge foundation. The height of the supports is adjusted according to the designed arch curve. When the components are assembled into arch segments, longitudinal steel bars with a diameter of 14mm are placed through the internal cavity. The segmented printed components are joined together with high-strength polymer mortar. After the components are assembled, cement grout is injected into the inner cavity of the arch component for connection.

[0120] S6: 12 steel structure column anchors are pre-embedded in the bridge foundation. The steel structure columns are installed and the steel structure longitudinal beams and cross braces are welded. A 2cm thick rubber pad is placed between the side of the cross brace and the printed component for cushioning. 2 concrete 3D printed sidewalk slabs, a total of 42 pieces, are placed on the steel structure cross braces of the sidewalk support system. They are installed in sequence according to their numbers. A certain structural gap is left between the sidewalk slabs and the bridge body to prevent mutual constraint and deformation.

[0121] This invention provides a spatial hyperboloid continuous bridge structure and its construction method based on a non-uniform lamination process. By innovatively employing an arched structural design, the 3D-printed concrete primarily bears compressive stress, avoiding tensile stress on weak interlayer interfaces and significantly improving structural safety margin. Simultaneously, the non-uniform lamination printing technology solves the common problems of weak interlayer interfaces and anisotropy in traditional concrete 3D-printed structures. The proposed non-uniform adaptive slicing method and path planning technology dynamically adjust layer thickness and printing speed according to the curvature of the components, effectively mitigating the step effect and improving surface smoothness and structural uniformity. Furthermore, the placement of U-shaped steel mesh at intervals during printing, followed by longitudinal steel reinforcement and grouting connections after component splicing, significantly enhances the overall tensile and compressive strength of the bridge. Meanwhile, the use of adjustable supports for precise on-site positioning effectively eliminates construction errors, simplifies the installation process of irregularly shaped bridges, and improves construction efficiency and accuracy. This technical solution breaks through the bottleneck of 3D printing construction of irregularly shaped bridges, promotes the application of complex spatial structure bridges in urban landscapes, and has significant engineering value and broad prospects for promotion.

[0122] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the ideas of this invention.

Claims

1. A spatial hyperboloid continuous bridge structure based on a non-uniform lamination process, characterized in that: The spatial hyperboloid continuous bridge structure includes a concrete 3D printed bridge body (1), which includes multiple longitudinally closely arranged arch span units. The arch span units are bent downward in the middle of the transverse direction and bent upward in the middle of the longitudinal direction. The whole structure is a hyperboloid structure with a longitudinal groove at the top. Each arch span unit includes multiple longitudinally closely arranged U-shaped segmented printed components, and the dividing lines between the U-shaped segmented printed components are radially distributed longitudinally. Multiple arch span units are longitudinally combined to form an arch-shaped whole. The bottom of the joint between two longitudinally adjacent arch span units protrudes downward, serving as a support point for the lower bridge foundation. The longitudinal width of the U-shaped segmented printed component gradually increases from the transverse center to both sides, and the thickness of the U-shaped segmented printed component gradually decreases from the transverse center to both sides. The U-shaped segmented printed component has longitudinally arranged through holes inside; The length of the through hole along the transverse structural direction of the U-shaped segmented printed component gradually decreases from the transverse center to both sides. The spatial hyperboloid continuous bridge structure also includes concrete 3D printed sidewalk slabs (2) and a steel structure sidewalk support system (3). The steel structure sidewalk support system (3) is located in the groove of the arched whole, and the concrete 3D printed sidewalk slab (2) is laid on top of the steel structure sidewalk support system (3); The two sides of the arch span unit are higher than the concrete 3D printed sidewalk slab (2), and the higher part serves as the handrails on both sides of the spatial hyperboloid continuous bridge structure. The steel structure pedestrian walkway support system (3) includes columns, longitudinal main beams and cross braces; The bottom of the column passes through the concrete 3D printed bridge body (1) and is supported by the top of the bridge foundation. The longitudinal main beam and the cross brace are connected in a crisscross pattern.

2. The spatial hyperboloid continuous bridge structure based on non-uniform lamination technology according to claim 1, characterized in that: The concrete 3D printed sidewalk slab (2) includes multiple multi-layer printed irregular planar printed components, which are laid on top of the longitudinal main beam and the cross brace; The lateral side edge shapes of the irregularly shaped planar printed component match the inner wall edge shapes of the handrail.

3. The construction method of a spatial hyperboloid continuous bridge structure based on non-uniform lamination technology as described in claim 2, characterized in that: The method includes: Establish a three-dimensional design model of a spatial hyperboloid continuous bridge structure; The concrete 3D printed bridge body (1) is longitudinally divided into multiple arch span units; An adaptive slicing method was used to longitudinally divide the arch span unit into multiple U-shaped segmented printed components; Based on the longitudinal width difference of the U-shaped segmented printed components, non-uniform lamination process control calculations are performed to print U-shaped segmented printed components. The U-shaped segmented printed components were transported to the site and assembled into an arch. Longitudinal steel bars were placed in the longitudinal through holes, and the U-shaped segmented printed components were connected by high-strength polymer mortar. Cement grout was then poured into the through holes. A steel structure pedestrian support system (3) is installed inside the concrete 3D printed bridge body (1), and a concrete 3D printed pedestrian slab (2) is laid on top of the steel structure pedestrian support system (3).

4. The construction method of the spatial hyperboloid continuous bridge structure based on non-uniform lamination process according to claim 3, characterized in that: An adaptive slicing method is used to longitudinally divide the arch span unit into multiple U-shaped segmented printed components, including: Extract the arch axis of each arch span element and establish multiple normal surfaces on the arch axis; Cut along the normal plane of the arch span unit to form a printable U-shaped segmented printed component; Extract the starting and ending surfaces of the U-shaped segmented printed component. Both surfaces are normal tangents to the arch axis and are not parallel. Non-uniform layer thickness slicing is performed on the U-shaped segmented printed component from the starting face to the ending face.

5. The construction method of the spatial hyperboloid continuous bridge structure based on non-uniform lamination process according to claim 4, characterized in that: Based on the longitudinal width difference of the U-shaped segmented printed components, non-uniform lamination process control calculations are performed to print the U-shaped segmented printed components, including: Extract the key points of the curved surface of the 3D printed concrete bridge body (1); Discretize the curve path between each pair of adjacent key points at equal distances, and insert uniform path points between each segment to form a path point sequence; Obtain the geometric curvature data of the three-dimensional design model of the concrete 3D printed bridge body (1), and set the reference layer thickness and reference printing speed; The layer thickness at each path point sequence is determined based on the local radius of curvature of the surface of the 3D-printed concrete bridge body (1). Calculate the speed of the printing equipment at each position based on the layer thickness; The motion speed data is interpolated to the corresponding path point to form a code that the path execution device can recognize. The moving speed of the path execution device is adjusted according to the motion speed to ensure that the amount of extruded material matches the motion speed in real time and to keep the material piled up evenly.

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