Suspended printing reinforced concrete bridge, construction device and printing method

Abstract

The invention relates to a suspended printing reinforced concrete bridge, a construction device and a printing method. The bridge comprises a pier, a variable cross-section beam, a bridge deck slab and longitudinal and transverse steel bars. The bridge pier is firstly printed, and then the variable cross-section beam and the bridge deck are printed. The variable cross-section beam is printed layer by layer from bottom to top, the upper layer is suspended and lengthened layer by layer compared with the lower layer, and longitudinal and transverse reinforcements are laid between layers. The construction device comprises a rail system, a frame system, a formwork system and a printing system, the frame system provides a working platform for the formwork system and the printing system, the formwork system adopts a suspended formwork to provide support for suspended printing of the variable cross-section beam, the printing system adopts a manipulator to install steel bars, and an extrusion head is adopted to extrude and stack and print concrete. According to the variable cross-section beam bridge, direct layered printing can be achieved, suspended printing of reinforced concrete is achieved through the suspended formwork system, the working procedure is simple, and the variable cross-section beam bridge is suitable for site construction.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing construction in civil engineering, and in particular to a suspended printed reinforced concrete bridge, a construction device and a printing method. Background Art

[0002] The existing 3D printed bridge technology is developing rapidly. The existing 3D printed bridges mainly include prefabricated concrete arch bridges, prefabricated prestressed beam bridges and all-steel structure bridges. Most of the above bridges are printed in the factory and then assembled on site. Reinforced concrete bridges that can be printed on site are very rare. There are two main reasons:

[0003] 1. The existing printed bridge structures are limited to arch bridges and prestressed beam bridges. The cross sections of both are subject to large compressive stress, and the lateral bearing capacity of layered printed concrete is small. Therefore, it is necessary to first print the cross section of the bridge on a plane, and then flip it 90 degrees and assemble it. It cannot be printed directly on site.

[0004] 2 Concrete cannot be printed in the air like steel. On-site bridge construction requires the use of formwork and supports. Once the supports and formwork are set up, concrete can be poured to construct the bridge, which cannot reflect the effectiveness of 3D printing.

[0005] In summary, a concrete bridge structure suitable for 3D printing needs to be proposed, and the corresponding construction method with few or no supports needs to be developed. Summary of the invention

[0006] The present invention aims to solve the deficiencies of the prior art and provides a suspended printed reinforced concrete bridge, a construction device and a printing method.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A suspended printed reinforced concrete bridge, comprising two piers arranged along the length direction of the bridge, each pier comprising a plurality of layers of pier monomers connected in sequence from top to bottom, each layer of pier monomers being composed of a plurality of 3D printed concrete single layers, longitudinal steel bars and transverse steel bars being embedded on the top of each layer of pier monomers, and vertical steel bars being inserted inside the piers;

[0009] A variable-section beam is provided on the top of the pier. The variable-section beam includes several layers of supporting beam monomers arranged sequentially from top to bottom. The lengths of the several layers of supporting beam monomers from bottom to top are sequentially extended to both sides. Each layer of supporting beam monomers is composed of several 3D printed concrete single layers. A steel mesh is laid on the top of each layer of supporting beam monomers. The steel mesh is welded and fixed by the transverse steel bars and the longitudinal steel bars of the supporting beam.

[0010] The top of the two variable-section beams jointly supports the bridge deck, which is composed of several single layers of 3D printed concrete. The bridge deck is equipped with several longitudinal steel bars along the length of the bridge.

[0011] Vertical steel bars are inserted inside the variable-section beam.

[0012] The length of the pier is 1m, the width is 7m, and the height is 2m; the height of the pier unit is 10cm, and the pier consists of 20 layers of pier units; the thickness of the 3D printed concrete single layer is 1cm, and the pier unit consists of 10 3D printed concrete single layers.

[0013] The width of the variable-section beam is 7m and the height is 3m; the height of the supporting beam unit is 10cm. The variable-section beam consists of 30 layers of supporting beam units. The length of the top layer of supporting beam units is 6m, and the length of the bottom layer of supporting beam units is 20cm. The suspended length of each upper layer of supporting beam units is 20cm longer than that of the lower layer of supporting beam units, and 10cm more on one side.

[0014] The above-mentioned construction device for suspended printing reinforced concrete bridges includes a track system, a frame system, a template system and a printing system;

[0015] The track system includes two parallel tracks, which are arranged on both sides of the length direction of the bridge;

[0016] The frame system is a support frame welded by two frame longitudinal beams and two frame cross beams. Four frame columns are arranged at the four corners of the bottom of the support frame. Moving wheels are installed at the bottom of the frame columns, and the moving wheels are rollingly installed on the track.

[0017] The formwork system includes four positioning beams installed between two frame longitudinal beams. The bottom of the positioning beam is rolled and installed on the frame longitudinal beam through a driving wheel driven by a motor. Two suspension rods are provided on each positioning beam. The suspension rods are connected to a winch. A hanging formwork is hung between the four suspension rods of every two positioning beams. The hanging formwork includes a step hanging formwork and a flat hanging formwork. The step hanging formwork includes three layers of formwork and the three layers of formwork are sequentially extended outward from bottom to top. The width of each layer of formwork is consistent with the width of the supporting beam monomer, and the height of each layer of formwork is consistent with the height of the supporting beam monomer.

[0018] The printing system includes a roller arranged on a frame crossbeam, the roller is driven by a motor, the roller is connected to a vertical rod, a guide beam that moves up and down is installed between the two vertical rods through a motor, gears and chains, a mobile mechanical arm with a concrete extrusion head and a mobile mechanical arm with a steel bar gripper are installed on the guide beam, and the mobile mechanical arm with the concrete extrusion head and the mobile mechanical arm with the steel bar gripper are both moved by a motor-driven rotating wheel.

[0019] The width of each layer of the hanging formwork is 7m, the height is 10cm and the length is 20cm.

[0020] The printing method of the above-mentioned suspended printing reinforced concrete bridge construction device comprises the following specific steps:

[0021] S1. The frame system is fixed in position, and the bridge piers are printed. The mobile robot arm with a concrete extruder prints the bridge pier monomers in layers. The bridge pier monomers are printed by 10 1cm thick 3D printed concrete layers. Each time a layer of bridge pier monomer is printed, the mobile robot arm with a steel bar gripper grabs the longitudinal and transverse steel bars and embeds them on the top of the bridge pier monomer for toughening. After printing five layers of bridge pier monomers, the mobile robot arm with a steel bar gripper grabs the vertical steel bars and inserts them into the five layers of bridge pier monomers to enhance the bending resistance of the bridge pier.

[0022] S2. Move the positioning beam to fix the position of the step hanging formwork, lift the lifting rod to fix the height of the step hanging formwork, and adjust the height of the four lifting rods to ensure the level of the step hanging formwork;

[0023] S3. The mobile mechanical arm with a steel bar gripper grabs the connected steel bar mesh and lays it on the already built bridge piers and ladder hanging formwork. The mobile mechanical arm with a concrete extruder moves longitudinally on the guide beam and the guide beam moves transversely on the frame beam to print the single concrete of the support beam. When the height is not met, the guide beam slides upward along the vertical rod to change the operating height.

[0024] S4. The three-layer support beam is a single section. After each section is printed, the ladder formwork moves 30cm to both sides along the longitudinal direction of the bridge. At the same time, the ladder formwork is raised 30cm upwards to print the next section of concrete.

[0025] S5. After the variable-section beam is printed, replace the flat plate hanging mold and print the concrete of the bridge deck, thus completing the printing of the entire bridge.

[0026] The beneficial effects of the present invention are as follows: the present invention provides a variable-section beam bridge that can be directly printed in layers, and adopts a hanging formwork system to realize suspended printing of reinforced concrete, with a simple process and suitable for on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the suspended printed reinforced concrete bridge in the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of two bridge piers in the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of two bridge piers and two variable-section beams in the present invention;

[0030] Figure 4 It is a schematic diagram of laying longitudinal reinforcements of a bridge deck on two variable-section beams in the present invention;

[0031] Figure 5 It is a structural schematic diagram of the suspended printing reinforced concrete bridge construction device of the present invention;

[0032] Figure 6 It is a schematic diagram of printing the first bridge pier and the variable-section beam using the construction device for printing reinforced concrete bridges in mid-air in the present invention;

[0033] Figure 7 It is a schematic diagram of printing the second bridge pier and the variable-section beam using the construction device for printing reinforced concrete bridge in mid-air in the present invention;

[0034] Figure 8 It is a schematic diagram of printing the bridge deck after replacing the plane hanging mold in the present invention;

[0035] In the figure: 1-bridge pier; 2-variable cross-section beam; 3-bridge deck; 4-track system; 5-frame system; 6-formwork system; 7-printing system;

[0036] 11-bridge pier monomer;

[0037] 21-support beam monomer;

[0038] 41-track;

[0039] 51-frame longitudinal beam; 52-frame cross beam; 53-frame column; 54-moving wheel;

[0040] 61-positioning beam; 62-suspender rod; 63-suspending formwork;

[0041] 71-roller; 72-vertical rod; 73-guide beam; 74-mobile mechanical arm with concrete extrusion head; 75-mobile mechanical arm with steel bar gripper;

[0042] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0043] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described in more detail by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0044] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0046] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0047] A suspended printed reinforced concrete bridge, such as Figures 1 to 4 As shown, it includes two piers 1 arranged along the length direction of the bridge, each pier 1 includes a plurality of layers of pier monomers 11 connected in sequence from top to bottom, each layer of pier monomers 11 is composed of a plurality of 3D printed concrete single layers, longitudinal steel bars and transverse steel bars are embedded on the top of each layer of pier monomers 11, and vertical steel bars are inserted inside the pier 1;

[0048] A variable-section beam 2 is provided on the top of the pier 1. The variable-section beam 2 includes a plurality of layers of supporting beam monomers 21 arranged sequentially from top to bottom. The lengths of the plurality of layers of supporting beam monomers 21 from bottom to top are sequentially extended to both sides. Each layer of supporting beam monomers 21 is composed of a plurality of 3D printed concrete single layers. A steel mesh is laid on the top of each layer of supporting beam monomers 21. The steel mesh is welded and fixed by the transverse steel bars and the longitudinal steel bars of the supporting beam. Vertical steel bars are inserted inside the variable-section beam 2.

[0049] The tops of the two variable-section beams 2 jointly support a bridge deck 3 , which is composed of a number of 3D printed concrete single layers. The bridge deck 3 is provided with a number of longitudinal steel bars arranged along the length direction of the bridge.

[0050] The number of piers 1 of a 3D bridge is two, and the number of corresponding variable-section beams 2 is also two.

[0051] The bridge first prints the bridge pier 1, and then prints the variable-section beam 2 and the bridge deck 3.

[0052] The width of pier 1 is 7m and the length is 1m. It is built with 3D printed concrete. The thickness of a single layer of 3D printed concrete is 1cm. Ten single layers of 3D printed concrete are absorbed to form a layer of pier monomer 11 with a thickness of 10cm. Each printed layer of pier monomer 11 can be provided with longitudinal and transverse reinforcements for toughening. The height of pier 1 is 2m. After printing five layers of pier monomer 11, the vertical reinforcement of the pier can be increased to enhance the bending resistance of pier 1.

[0053] The variable cross-section beam 2 is printed horizontally from bottom to top. The width of the layer of the supporting beam monomer 21 from bottom to top is 7m, the layer height is 10cm, and the upper layer is suspended 20cm higher than the lower layer, for a total of 30 layers. That is, the maximum length of the variable cross-section beam 2 is 6m, the height is 3m, and the span of the bridge composed of two variable cross-section beams 2 is 12m. Steel mesh is laid between the supporting beam monomers 21 to improve the strength. The steel mesh is composed of longitudinal steel bars and transverse steel bars.

[0054] A layer of bridge deck 3 is printed on the top of the variable-section beam 2. The longitudinal reinforcement of the bridge deck 3 is arranged along the entire length of the two variable-section beams 2. The concrete of the bridge deck 3 needs to have a higher flatness requirement.

[0055] At the same time, the present invention provides a construction device for suspended printing reinforced concrete bridges, such as Figure 5 , Figure 6 As shown, the construction device includes a track system 4, a frame system 5, a template system 6 and a printing system 7.

[0056] The track system 4 includes two parallel tracks 41, which are arranged on both sides of the bridge in the length direction and have an I-beam cross section. For a waterless environment, the track 41 can directly level the site to build a track foundation. For a water environment, the track 41 can be provided with steel pipe piles and Bailey beams to provide a track foundation.

[0057] The frame system 5 provides a working platform for the template system 6 and the printing system 7, and is welded from section steel. The frame system 5 is a support frame welded from two frame longitudinal beams 51 and two frame cross beams 52. Four frame columns 53 are provided at the four corners of the bottom of the support frame. The bottom of the frame columns 53 is equipped with moving wheels 54, which are rollingly installed on the track 41 and can freely move along the longitudinal direction of the bridge on the track 41.

[0058] The formwork system 6 includes a positioning beam 61 , a hanging rod 62 , and a hanging formwork 63 .

[0059] A positioning beam 61 is mounted on the frame longitudinal beam 51, and a driving wheel is provided at the bottom of the positioning beam 61. The driving wheel is driven by a motor and can move freely on the frame longitudinal beam 51. There are four positioning beams 61 on the frame longitudinal beam 51, and two suspension rods 62 are connected to the middle of each positioning beam 61. The four suspension rods 62 on the two positioning beams 61 jointly suspend a hanging mold 63. The suspension rods 62 control the height and levelness of the hanging mold 63 through a winch.

[0060] The hanging formwork 63 includes a ladder hanging formwork and a flat hanging formwork. The ladder hanging formwork has three layers, a layer width of 7m, a layer length of 20cm, and a layer height of 10cm, that is, the height of a supporting beam monomer 21. After the concrete printing of each three layers of supporting beam monomers 21 is completed, the ladder hanging formwork moves 30cm to both sides along the longitudinal bridge direction, and the height is raised by 30cm to provide support for the concrete of the next three layers of supporting beam monomers 21.

[0061] The printing system 7 includes a roller 71 , a vertical rod 72 , a guide beam 73 , a mobile mechanical arm 74 with a concrete extrusion head, and a mobile mechanical arm 75 with a steel bar gripper.

[0062] The frame crossbeam 52 is provided with a movable roller 71, which is driven by a motor. The roller 71 is connected to the vertical rod 72, which is connected to the guide beam 73. The guide beam 73 can slide up and down on the vertical rod 72 and is driven by a motor, a gear and a chain. A mobile mechanical arm 74 with a concrete extrusion head and a mobile mechanical arm 75 with a steel bar gripper are installed on the guide beam 73 to realize concrete printing and steel bar loading and installation respectively. A slidable track is set between the mobile mechanical arm 74 with a concrete extrusion head, the mobile mechanical arm 75 with a steel bar gripper and the guide beam 73, which can move upward on the longitudinal bridge, and the motor drives the rotating wheel to move. The mobile mechanical arm 74 with a concrete extrusion head and the mobile mechanical arm 75 with a steel bar gripper realize the movement in the transverse direction of the bridge through the roller 71 of the guide beam 73, and realize the movement in height through the vertical rod 72.

[0063] In summary, the printing process using the construction device is as follows: Figures 6 to 8 As shown:

[0064] S1, the frame system 5 is fixed in position, the bridge pier 1 is printed, the mobile mechanical arm 74 with a concrete extruder prints the bridge pier monomer 11 in layers, the bridge pier monomer 11 is printed by 10 1 cm thick 3D printed concrete single layers, each time a layer of the bridge pier monomer 11 is printed, the mobile mechanical arm 75 with a steel bar gripper grabs the longitudinal steel bars and the transverse steel bars and embeds them on the top of the bridge pier monomer 11 for toughening, after printing five layers of the bridge pier monomer 11, the mobile mechanical arm 75 with a steel bar gripper grabs the vertical steel bars and inserts them into the five layers of the bridge pier monomer 11 to enhance the bending resistance of the bridge pier 1;

[0065] S2, move the positioning beam 61 to fix the position of the step hanging formwork, the lifting rod 62 to fix the height of the step hanging formwork, and adjust the heights of the four lifting rods 62 to ensure the level of the step hanging formwork;

[0066] S3, the mobile mechanical arm 75 with a steel bar gripper grabs the connected steel bar mesh and lays it on the already built bridge pier 1 and the ladder hanging formwork, the mobile mechanical arm 74 with a concrete extruder moves longitudinally on the guide beam 73, and the guide beam 73 moves transversely on the frame cross beam 52 to print the concrete of the support beam monomer 21. When the height is not satisfied, the guide beam 73 slides upward along the vertical rod 72 to change the operating height;

[0067] S4, the three-layer support beam monomer 21 is a section. After each section is printed, the ladder formwork moves 30 cm to both sides along the longitudinal direction of the bridge, and at the same time, the height of the ladder formwork is raised by 30 cm to print the next section of concrete;

[0068] S5. After the printing of the variable-section beam 2 is completed, the flat plate hanging formwork is replaced and the concrete of the bridge deck 3 is printed, thus completing the printing of the entire bridge.

[0069] In another optional embodiment of the present invention, bridge deck structures such as bridge deck guardrails may continue to be printed.

[0070] In another optional embodiment of the present invention, the number of piers 1 and variable-section beams 2 can be increased.

[0071] In another optional embodiment of the present invention, the cross section of the bridge pier 1 may be circular.

[0072] In another optional embodiment of the present invention, vertical steel bars may be inserted into the variable-section beams 2 constructed in layers, so as to enhance the shear resistance of the cross section and improve the shear resistance between layers.

[0073] In another optional embodiment of the present invention, the longitudinal length of the hanging mold 63 may not be uniform, that is, it may vary within a safe range, so that the lower edge of the printed bridge is an arc.

[0074] In another optional embodiment of the present invention, the longitudinal steel bars and the transverse steel bars may be fixed by welding, and the welding method may be a welding robot arm, that is, adding a welding robot arm.

[0075] The reinforced concrete bridge suitable for 3D printing and the construction device for suspended printing of the present application have the following advantages:

[0076] (1) The structure is novel. It is no longer a common arch bridge or prestressed beam bridge. It does not need to be printed in cross section and then flipped, but is directly 3D printed.

[0077] (2) The new structure is no longer a masonry structure without steel bars, nor a prestressed structure, but a composite additive made of steel bars and concrete directly 3D printed without the need for flipping construction.

[0078] (3) It can be printed in mid-air on site, and the 3D printed bridge can be printed in mid-air by using a bracket-less method.

[0079] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A suspended printed reinforced concrete bridge, characterized in that: The invention comprises two piers (1) arranged along the length direction of the bridge, each pier (1) comprises a plurality of layers of pier monomers (11) connected in sequence from top to bottom, each layer of pier monomers (11) is composed of a plurality of 3D printed concrete single layers, a longitudinal steel bar and a transverse steel bar are embedded on the top of each layer of pier monomers (11), and a vertical steel bar is inserted inside the pier (1); A variable-section beam (2) is provided on the top of the pier (1), and the variable-section beam (2) includes a plurality of layers of support beam monomers (21) arranged sequentially from top to bottom, and the lengths of the plurality of layers of support beam monomers (21) from bottom to top are sequentially extended toward both sides, and each layer of support beam monomers (21) is composed of a plurality of 3D printed concrete single layers, and a steel mesh is laid on the top of each layer of support beam monomers (21), and the steel mesh is welded and fixed by the support beam transverse steel bars and the support beam longitudinal steel bars; The tops of the two variable-section beams (2) jointly support a bridge deck (3), the bridge deck (3) being composed of a plurality of 3D-printed concrete single layers, and a plurality of longitudinal steel bars arranged along the length direction of the bridge being arranged in the bridge deck (3).

2. The suspended printed reinforced concrete bridge according to claim 1, characterized in that: Vertical steel bars are inserted inside the variable-section beam (2).

3. The suspended printed reinforced concrete bridge according to claim 2, characterized in that: The length of the pier (1) is 1m, the width is 7m, and the height is 2m; the height of the pier monomer (11) is 10cm, and the pier (1) is composed of 20 layers of pier monomers (11); the thickness of the 3D printed concrete single layer is 1cm, and the pier monomer (11) is composed of 10 3D printed concrete single layers.

4. The suspended printed reinforced concrete bridge according to claim 3 is characterized in that: The variable-section beam (2) has a width of 7m and a height of 3m; the height of the supporting beam monomer (21) is 10cm; the variable-section beam (2) is composed of 30 layers of supporting beam monomers (21); the length of the top layer of supporting beam monomers (21) is 6m, and the length of the bottom layer of supporting beam monomers (21) is 20cm; the suspended length of each upper layer of supporting beam monomers (21) is 20cm longer than that of the lower layer of supporting beam monomers (21), and the single side increases by 10cm.

5. A construction device for suspended printing reinforced concrete bridges as claimed in claim 4, characterized in that: It includes a track system (4), a frame system (5), a template system (6) and a printing system (7); The track system (4) comprises two parallel tracks (41), and the two tracks (41) are arranged on both sides of the bridge in the length direction; The frame system (5) is a support frame formed by welding two frame longitudinal beams (51) and two frame cross beams (52). Four frame columns (53) are arranged at the four corners of the bottom of the support frame. Moving wheels (54) are installed at the bottom of the frame columns (53). The moving wheels (54) are rollingly installed on the track (41). The template system (6) comprises four positioning beams (61) installed between two frame longitudinal beams (51), the bottom of the positioning beam (61) is rollingly installed on the frame longitudinal beam (51) through a driving wheel, the driving wheel is driven by a motor, each positioning beam (61) is provided with two suspension rods (62), the suspension rods (62) are connected to a winch, a hanging form (63) is hung between the four suspension rods (62) of every two positioning beams (61), the hanging form (63) comprises a step hanging form and a flat hanging form, the step hanging form comprises three layers of templates, and the three layers of templates are sequentially extended outward from bottom to top, the width of each layer of template is consistent with the width of the supporting beam monomer (21), and the height of each layer of template is consistent with the height of the supporting beam monomer (21); The printing system (7) comprises a roller (71) arranged on a frame crossbeam (52), the roller (71) being driven by a motor, the roller (71) being connected to a vertical rod (72), a guide beam (73) being installed between the two vertical rods (72) via a motor, a gear and a chain, a mobile mechanical arm (74) with a concrete extrusion head and a mobile mechanical arm (75) with a steel bar gripper being installed on the guide beam (73), and the mobile mechanical arm (74) with a concrete extrusion head and the mobile mechanical arm (75) with a steel bar gripper being moved by a rotating wheel driven by the motor.

6. The construction device for suspended printing reinforced concrete bridge according to claim 5 is characterized in that: The width of each layer of template of hanging formwork (63) is 7m, and height is 10cm, and length is 20cm.

7. A printing method for a construction device for suspended printing reinforced concrete bridges as claimed in claim 6, characterized in that: The specific steps are: S1, the frame system (5) is fixed in position, the bridge pier (1) is printed, and a mobile mechanical arm (74) with a concrete extruder prints the bridge pier monomer (11) in layers. The bridge pier monomer (11) is printed with 10 1 cm thick 3D printed concrete single layers. Each time a layer of the bridge pier monomer (11) is printed, a mobile mechanical arm (75) with a steel bar gripper grabs the longitudinal steel bars and the transverse steel bars and embeds them on the top of the bridge pier monomer (11) for toughening. After printing five layers of the bridge pier monomer (11), the mobile mechanical arm (75) with a steel bar gripper grabs the vertical steel bars and inserts them into the five layers of the bridge pier monomer (11) to enhance the bending resistance of the bridge pier (1); S2, moving the positioning beam (61) to fix the position of the step hanging formwork, the lifting and lowering rods (62) to fix the height of the step hanging formwork, and adjusting the heights of the four lifting and lowering rods (62) to ensure the level of the step hanging formwork; S3, a mobile mechanical arm (75) with a steel bar gripper grabs the connected steel bar mesh and lays it on the already built bridge pier (1) and the ladder hanging formwork, and a mobile mechanical arm (74) with a concrete extruder moves longitudinally on the guide beam (73), and the guide beam (73) moves transversely on the frame cross beam (52) to print the concrete of the support beam monomer (21). When the height is not satisfied, the guide beam (73) slides upward along the vertical rod (72) to change the operating height; S4, the three-layer support beam monomer (21) is a section. After each section is printed, the ladder formwork moves 30 cm to both sides along the longitudinal direction of the bridge, and at the same time, the height of the ladder formwork is raised by 30 cm to print the next section of concrete; S5. After the variable cross-section beam (2) is printed, the flat plate hanging mold is replaced and the concrete of the bridge deck (3) is printed, thus completing the printing of the entire bridge.

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