Preparation method of prefabricated composite beam based on different joint surfaces

Abstract

The present invention discloses a method for preparing prefabricated composite beams based on different bonding surfaces, including the following steps: S1: according to the construction drawings or detailed drawings, check whether the parameters of the stirrups meet the predetermined requirements. If they meet the predetermined requirements, implement step S2; if they do not meet the predetermined requirements, implement step S2'; S2: select a component mold to directly prepare the prefabricated part of the composite beam without roughening the bonding surface; S2': select a component mold equipped with a rough surface prefabricated structure to simultaneously prepare the prefabricated part of the composite beam and roughen its bonding surface. This method can flexibly select whether to implement the roughening process according to the relationship between the stirrup parameters in the beam and the various parameters of the prefabricated composite beam, and fully considers the interface shear effect of the original stirrups in the beam, thereby improving the preparation efficiency and reducing the preparation cost. In addition, for the prefabricated composite beams that need to increase the roughness of the bonding surface, the roughening of the bonding surface can be achieved at the component prefabrication stage.

Description

Technical Field

[0001] The invention relates to the technical field of reinforced concrete prefabricated components, and in particular to a method for preparing prefabricated composite beams based on different bonding surfaces. Background Art

[0002] In the prefabricated construction projects at home and abroad, composite beams are the main prefabrication and assembly method of structural beams. Composite beams with reinforced concrete as the main material are most widely used in construction, municipal engineering, and bridge engineering. They are mainly composed of the prefabricated part at the bottom of the beam and the post-cast part at the top of the beam. Therefore, unlike pure cast-in-place beams and pure prefabricated beams, their mechanical properties will be affected by the performance of the prefabrication and cast-in-place interface.

[0003] At present, the preparation method of reinforced concrete composite beams is derived from the pure cast-in-place preparation concept, and its mainstream joint surface treatment methods mainly include the following:

[0004] 1. Artificial or mechanical roughening: For formed concrete components, artificial or mechanical roughening is usually used. This method can effectively remove the slurry and loose layer on the concrete surface to form a rough bonding surface.

[0005] 2. Surface roughening: Before the concrete reaches the initial setting state, use special tools to roughen the concrete surface to form a concave and convex texture of a certain depth. The roughening operation time should be comprehensively controlled according to factors such as concrete mix ratio, temperature and air humidity to ensure that the difference in roughness of the rough surface should not be less than 4mm.

[0006] 3. Chemical water washing exposed stone: Use chemical retarder to brush the surface of the formwork or the surface of the newly poured concrete. After the component is cured, use high-pressure water to wash the concrete surface to expose the aggregate to form a rough surface. This method can select the appropriate retarder type according to the design requirements to achieve the ideal rough surface effect.

[0007] However, on the one hand, the above three methods of joint surface treatment do not consider the interface shearing effect of the original stirrups in the beam. In actual production, simple rough surface treatment is used, which wastes materials, affects preparation efficiency, increases preparation costs and process risks, and has quality risks caused by improper joint surface treatment. On the other hand, the above three methods of joint surface treatment are only for formed concrete components or basically formed concrete components (initial setting state), and require additional processes, and cannot be flexibly adjusted according to the actual needs of different joint surfaces. Summary of the invention

[0008] The purpose of the present invention is to provide a method for preparing prefabricated composite beams based on different joint surfaces. The method can flexibly select whether to implement a roughening process according to the relationship between the stirrup parameters in the beam and the various parameters of the prefabricated composite beam, and fully consider the interface shearing effect of the original stirrups in the beam, thereby improving the preparation efficiency, reducing the preparation cost, and reducing the quality risk caused by improper treatment of the composite beam joint surface. In addition, for the prefabricated composite beams that need to increase the roughness of the joint surface, the roughening of the joint surface can be achieved at the same time in the prefabrication stage of the component, which greatly improves the production efficiency, thereby solving the technical problems described in the background technology.

[0009] To achieve the above purpose, the specific technical solutions adopted by the present invention are as follows:

[0010] A method for preparing a prefabricated composite beam based on different bonding surfaces, the key of which is to include the following steps:

[0011] S1: According to the construction drawings or detailed drawings, check whether the parameters of the stirrups meet the predetermined requirements. If they meet the predetermined requirements, implement step S2; if they do not meet the predetermined requirements, implement step S2';

[0012] S2: Select the component mold to directly prepare the prefabricated part of the composite beam, and the joint surface is not roughened;

[0013] S2': Select a component mold with a rough surface prefabricated structure and simultaneously prepare the prefabricated part of the composite beam and roughen its joint surface;

[0014] S3: The prefabricated part is transported to the site for installation, and the cast-in-place part is constructed;

[0015] S4: Complete maintenance work;

[0016] S5: Repeat steps S1, S2 or S2', S3, S4.

[0017] Optionally, in step S1, the number of stirrups n is checked according to the structural construction drawing or the detailed drawing. sv , Area of ​​single stirrup A sv , stirrup spacing s sv The beam length L and stirrup yield strength f sv , cast-in-place layer thickness a, beam height h, longitudinal reinforcement tensile yield strength f y , longitudinal reinforcement area A s , effective height of beam section h0, adjustment coefficient of concrete compressive strength α1, width of precast beam b, concrete compressive strength f c Does the relationship between satisfy formula (I):

[0018]

[0019] Optionally, in step S2, according to the design size and shape of the prefabricated part of the composite beam, a component mold that meets the requirements is assembled and closed; wherein: the component mold includes two bottom frames arranged opposite to each other in the beam width direction, and a fixed-size bottom plate is selectively provided on the bottom frame, and a rotatable side mold is hinged on the outer side of each of the bottom frames through a hinge seat, and the two are connected by a pull rod, and a concrete pouring mold cavity is formed on the fixed-size bottom plate between the two rotatable side molds through two end mold plates, and reinforcement holes for the longitudinal reinforcement of the beam to pass through are also reserved on the end mold plates.

[0020] Optionally, the distance between the two bottom frames is adjusted by a telescopic structure.

[0021] Optionally, in step S2', when the rough surface is processed by the rough surface prefabricated structure, it should be ensured that the concave-convex depth of the rough surface is not less than 6 mm, and the area of ​​the rough surface is not less than 80% of the area of ​​the bonding surface.

[0022] Optionally, the rough surface prefabricated structure includes a mounting plate arranged according to the length of the beam, the mounting plate is installed above the concrete casting mold cavity of the component mold and can be moved in the direction of the beam width, and a strip-shaped through groove that adapts to the length of the beam is opened on the mounting plate, and a plurality of lifting components that can adjust the position in the direction of the beam length are arranged in the strip-shaped through groove, and the lower end of the lifting component extends into the concrete casting mold cavity and is detachably installed with a roughening strip.

[0023] Optionally, slides adapting to the beam width are respectively provided on the first and last pull rods of the component mold, and the first and last plate ends of the mounting plate are respectively restricted in the corresponding slides by bolts.

[0024] Optionally, the lifting assembly includes a lifting screw rod arranged on the roughening strip in the direction of the beam height, an adjusting nut is sleeved on the lifting screw rod, and the adjusting nut is placed on the strip-shaped through groove.

[0025] Optionally, a limit groove arranged in parallel with the strip-shaped through groove is also provided on the mounting plate, and a limit rod is connected to each of the roughening strips and passes through the limit groove in the direction of the beam height. The limit rod is used to cooperate with the lifting assembly to always limit the roughening strip in the direction adapting to the beam width.

[0026] Optionally, a first scale for indicating the lifting height of the roughening strip in the beam height direction is provided on the limiting rod, and a second scale for indicating the adjustment position of the roughening strip in the beam length direction is also provided near the limiting groove.

[0027] The remarkable effects of the present invention are:

[0028] (1) By studying the relationship between the parameters of the stirrups in the beam and the parameters of the prefabricated composite beam, it is determined whether the joint surface needs to be roughened, so as to effectively utilize the interface shear resistance of the original stirrups in the beam and delete the roughening process of some qualified components to improve the preparation efficiency of the composite beam, reduce material waste, and reduce labor and material costs. At the same time, it can also effectively avoid potential quality risks caused by improper roughening process. In addition, for the prefabricated composite beams that need to increase the roughness of the joint surface, the joint surface can be roughened at the same time during the prefabrication stage of the components, which greatly improves production efficiency and is more flexible;

[0029] (2) The present invention optimizes the design of the component mold, adopts a bottom frame with adjustable spacing, a rotatable side mold and a linkage structure of a pull rod, which greatly improves the adaptability and flexibility of the mold, so that the mold can meet the preparation requirements of prefabricated parts of composite beams of different sizes, and is convenient for rapid demoulding, further improving the preparation efficiency;

[0030] (3) The design of the rough surface prefabricated structure is particularly ingenious. Through the strip-shaped through grooves and lifting components on the mounting plate, the position of the roughening strip on the beam length and the depth on the beam height can be flexibly adjusted to ensure the accuracy and consistency of the rough surface treatment and meet the requirements of the bonding surface treatment (that is, the concave and convex depth is not less than 6mm, and the rough surface area is not less than 80% of the bonding surface area). At the same time, the setting of the slide and the limit groove ensures that the roughening strip is always calibrated in the direction of adapting to the beam width, avoiding errors and deviations in operation;

[0031] (4) The present invention is repeatable and extensible. Before the preparation of the prefabricated composite beam, it can be determined whether the rough surface prefabricated structure is suitable based on the relationship between various parameters. When the prefabricated composite beam is prepared, the mold size can be adjusted according to the size, shape and other adaptability of the composite beam. At the same time, the style, quantity and distribution of the roughened strips can be selectively adjusted to meet the construction requirements of the joint surface. This flexibility and adaptability make the present invention have high practical value and market promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0033] Figure 1 This is a schematic diagram of the process of preparing a prefabricated composite beam in Example 1;

[0034] Figure 2 FIG. 1 is a derivation diagram of the relationship between various parameters of the composite beam in Example 1 (I);

[0035] Figure 3 FIG2 is a derivation diagram of the relationship between various parameters of the composite beam in Example 1;

[0036] Figure 4 FIG3 is a derivation diagram of the relationship between various parameters of the composite beam in Example 1;

[0037] Figure 5 is an end view of the component mold in Example 2;

[0038] Figure 6 is an end view of the component mold in Example 3;

[0039] Figure 7 It is a three-dimensional diagram (I) of the rough surface prefabricated structure in Example 4;

[0040] Figure 8 This is an end view of the rough surface prefabricated structure in Example 4;

[0041] Fig. 9 A top view of the rough surface prefabricated structure in Example 4;

[0042] Fig.10 It is a right side view of the rough surface prefabricated structure in the fourth embodiment;

[0043] Fig.11 It is a left view of the rough surface prefabricated structure in the fourth embodiment;

[0044] Fig.12 It is a three-dimensional diagram (II) of the rough surface prefabricated structure in Example 4;

[0045] Fig.13 for Fig.12 A partial enlarged view of the middle A part;

[0046] Note in the figure:

[0047] 100-component mold, 101-bottom frame, 102-fixed-size bottom plate, 103-rotatable side mold, 104-pull rod, 105-telescopic structure, 106-locking nut, 107-card seat;

[0048] 200-rough surface prefabricated structure, 201-mounting plate, 202-strip through groove, 203-lifting assembly, 204-roughened strip, 205-slide, 206-bolt, 2031-lifting screw, 2032-adjusting nut, 207-limiting groove, 208-limiting rod, 209-first scale, 210-second scale. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0051] Embodiment 1:

[0052] See also Figure 1 This embodiment provides a method for preparing a prefabricated composite beam based on different bonding surfaces, comprising the following steps:

[0053] S1: According to the construction drawings or detailed drawings, check whether the parameters of the stirrups meet the predetermined requirements. If they meet the predetermined requirements, implement step S2; if they do not meet the predetermined requirements, implement step S2';

[0054] S2: Select component mold 100 to directly prepare the prefabricated part of the composite beam, and the joint surface is not roughened.

[0055] deal with;

[0056] S2': Select the component mold 100 equipped with the rough surface prefabricated structure 200 to simultaneously prepare the prefabricated part of the composite beam and roughen its joint surface;

[0057] S3: The prefabricated part is transported to the site for installation, and the cast-in-place part is constructed;

[0058] S4: Complete maintenance work;

[0059] S5: Repeat steps S1, S2 or S2', S3, S4.

[0060] In the specific implementation, in step S1, the number of stirrups n is checked according to the structural construction drawing or the detailed drawing. sv , Area of ​​single stirrup A sv , stirrup spacing s sv The beam length L and stirrup yield strength f sv , cast-in-place layer thickness a, beam height h, longitudinal reinforcement tensile yield strength f y , longitudinal reinforcement area A s , effective height of beam section h0, adjustment coefficient of concrete compressive strength α1, width of precast beam b, concrete compressive strength f c Does the relationship between satisfy formula (I):

[0061]

[0062] The derivation process of formula (I) in this embodiment is as follows:

[0063] Formula symbol definition:

[0064] σ c : concrete stress;

[0065] b=b′ f : beam width;

[0066] x: height of the compression zone of the concrete section;

[0067] σ′ s A′ s : Compression steel bar stress and compression steel bar area;

[0068] σ s A s : tensile reinforcement stress and tensile reinforcement area;

[0069] τ c A c : Shear stress and area of ​​concrete at the bonding surface;

[0070] nτ sv A sv : Number, shear stress and area of ​​stirrups passing through the joint surface;

[0071] h0: effective height of beam section

[0072] L: beam length;

[0073] M, V: beam bending moment and shear force;

[0074] S, I: area moment corresponding to the cast-in-place part of the beam section and moment of inertia of the entire beam section;

[0075] Figure 2 The equilibrium equation is:

[0076] σ c b′ f x+σ′ s A′ s =τ c A c +nτ sv A sv

[0077] τ c A c +nτ sv A sv =σ s A s

[0078] Figure 3 The equilibrium equation is:

[0079] σ c b′ f x+σ′ s A′ s =σ s A s

[0080]

[0081] From the knowledge of structural mechanics, we can get:

[0082]

[0083]

[0084] Consider conservatively and ignore the effect of steel bars in the compression zone, that is, σ′ s A′ s = 0, and only the effect of the stirrups on the bonding surface is considered, that is, τ c A c =0, from the above equilibrium equation we can get:

[0085] Interface shear force:

[0086]

[0087] Interface shear bearing capacity:

[0088] (The symbol Indicates rounding down)

[0089] According to the requirement that the bearing capacity is not less than the action, we can get:

[0090] V R ≥V s

[0091] See also Figure 4 After derivation and simplification, the number of stirrup legs n can be obtained sv , Area of ​​single stirrup A sv , stirrup spacing s sv With beam length L, f sv , cast-in-place layer thickness a, beam height h, steel bar tensile yield strength f y , longitudinal reinforcement area A s , effective height of beam section h0, α1, width of precast beam b, compressive strength of concrete f c The relationship between:

[0092]

[0093] Embodiment 2:

[0094] See also Figure 5 In this embodiment, in step S2, a component mold 100 that meets the requirements is assembled and closed according to the design size and shape of the prefabricated part of the composite beam; wherein: the component mold 100 includes two bottom frames 101 arranged opposite to each other in the beam width direction, and a fixed-size bottom plate 102 is selectively arranged on the bottom frame 101, and a rotatable side mold 103 is hinged on the outer side of each of the bottom frames 101 through a hinge seat, and the two are connected by a tie rod 104, and a concrete pouring mold cavity is formed on the fixed-size bottom plate 102 through two end molds (not shown in the figure) between the two rotatable side molds 103, and reinforcement holes for the longitudinal reinforcement of the beam to pass through are reserved on the end mold.

[0095] In this embodiment, one end of the tie rod 104 is hinged on one of the rotatable side molds 103, and the other end of the tie rod 104 is provided with a locking nut 106. A clamping seat 107 is provided on the other rotatable side mold 103, and the tie rod 104 can be locked on the clamping seat 107 by the locking nut 106. After the composite beam is prepared, it only needs to loosen the locking nut 106 and rotate the rotatable side mold 103 to quickly demould.

[0096] Embodiment three:

[0097] like Figure 6 As shown, the distance between the two bottom frames 101 is adjusted by a telescopic structure 105. The telescopic structure 105 is designed by a telescopic screw and a threaded sleeve, and a hand-adjustable nut is arranged on the threaded sleeve. In some other embodiments, in order to realize the automatic adjustment of the distance between the bottom frames 101, the telescopic structure 105 can also be in the form of a cylinder, a hydraulic cylinder, a servo electric cylinder, etc.

[0098] Embodiment 4:

[0099] In this embodiment, when the rough surface is processed by the rough surface prefabricated structure 200 in step S2', it should be ensured that the concave-convex depth of the rough surface is not less than 6 mm, and the rough surface area is not less than 80% of the bonding surface area. Figures 7 to 13 As shown, specifically, the rough surface prefabricated structure 200 includes a mounting plate 201 set according to the beam length, the mounting plate 201 is installed above the concrete casting mold cavity of the component mold 100, and can move in the beam width direction, and a strip-shaped through groove 202 adapted to the beam length is opened on the mounting plate 201, and a plurality of lifting components 203 that can adjust the position in the beam length direction are arranged in the strip-shaped through groove 202, and the lower end of the lifting component 203 extends into the concrete casting mold cavity, and a roughening strip 204 is detachably installed. Preferably, the bottom of the roughening strip 204 is set to be an arc surface to facilitate later demoulding.

[0100] In specific implementation, slides 205 adapted to the beam width are respectively arranged on the first and last pull rods 104 of the component mold 100, and the first and last plate ends of the mounting plate 201 are respectively restricted in the corresponding slides 205 by bolts 206. The lifting assembly 203 includes a lifting screw 2031 arranged on the roughening strip 204 in the direction of the beam height, and an adjusting nut 2032 is sleeved on the lifting screw 2031, and the adjusting nut 2032 is placed on the strip-shaped through groove 202.

[0101] In order to ensure that the roughening strip 204 is always calibrated in the direction of adapting to the beam width, a limiting groove 207 arranged in parallel with the strip-shaped through groove 202 is also opened on the mounting plate 201, and a limiting rod 208 is also connected to each of the roughening strips 204, which passes through the limiting groove 207 in the direction of the beam height. The limiting rod 208 is used to cooperate with the lifting assembly 203 to always limit the roughening strip 204 in the direction of adapting to the beam width. In order to improve the calibration accuracy of the roughening strip 204 in the direction of the beam length and beam height, a first scale 209 for indicating the lifting height of the roughening strip 204 in the direction of the beam height is set on the limiting rod 208, and a second scale 210 for indicating the adjustment position of the roughening strip 204 in the direction of the beam length is also set near the limiting groove 207.

[0102] Embodiment five:

[0103] In the previous embodiments, we have explored how to construct and manufacture various components and molds of composite beams. However, in order to ensure the overall performance of the composite beam, in addition to the reasonable design of the mold and the rough surface treatment, the concrete pouring process of the prefabricated part of the composite beam is also crucial. In this embodiment, we will introduce in detail how to control the concrete pouring process of the prefabricated part of the composite beam.

[0104] First, ensure that the quality of concrete materials meets the design requirements. This includes the strength, workability, durability and other properties of concrete. During the concrete production process, the mix ratio should be strictly followed to control the proportion of cement, aggregate, water and additives.

[0105] Secondly, before pouring, the mold should be thoroughly cleaned and inspected to ensure that there is no debris or water inside the mold, and that all templates are tightly connected without gaps. At the same time, the position and size of the steel skeleton should be accurate without offset or deformation.

[0106] During the pouring process, the method of pouring in layers and vibrating layer by layer should be adopted. The height of each pouring layer should not be too large, generally controlled at about 30cm, to ensure that the concrete can be fully compacted. When vibrating, appropriate vibrating equipment should be used, such as an inserted vibrator or a flat vibrator, to fully vibrate the concrete and eliminate bubbles and voids.

[0107] After pouring, the concrete should be fully cured. This includes keeping the concrete surface moist, controlling the ambient temperature and humidity, etc. The curing time is generally not less than 14 days to ensure that the concrete can reach the strength required by the design.

[0108] Finally, before demoulding, the prefabricated part of the composite beam should be fully inspected to ensure that there are no defects such as cracks and voids. At the same time, the rough surface should be inspected to ensure that it meets the design requirements. If there are any problems, they should be handled and repaired in time.

[0109] By implementing the concrete pouring and curing measures in this embodiment, it can be ensured that the quality of the prefabricated part of the composite beam meets the design requirements, laying a solid foundation for subsequent construction and use.

[0110] In summary, by studying the relationship between the parameters of the stirrups in the beam and the parameters of the prefabricated composite beam, it is determined whether the joint surface needs to be roughened, so as to effectively utilize the interface shearing effect of the original stirrups in the beam, delete the rough surface treatment process of some qualified components, so as to improve the preparation efficiency of the composite beam, reduce material waste, reduce labor and material costs, and effectively avoid potential quality risks caused by improper rough surface process processing. In addition, for the prefabricated composite beams that need to increase the roughness of the joint surface, the rough treatment of the joint surface can be achieved at the component prefabrication stage, which greatly improves the production efficiency and flexibility; the present invention optimizes the design of the component mold 100, adopts the bottom frame 101 with adjustable spacing, the rotatable side mold 103 and the linkage structure of the pull rod 104, which greatly improves the adaptability and flexibility of the mold, so that the mold can adapt to the preparation requirements of the prefabricated parts of composite beams of different sizes, and is convenient for rapid demoulding, further improving the preparation efficiency; the design of the rough surface prefabricated structure 200 is particularly ingenious. Through the strip-shaped through groove 202 and the lifting assembly 203 on the mounting plate 201, the position of the roughening strip 204 on the beam length and the depth on the beam height can be flexibly adjusted to ensure the accuracy and consistency of the rough surface treatment and meet the requirements of the bonding surface treatment (i.e., the concave-convex depth is not less than 6mm, and the rough surface area is not less than 80% of the bonding surface area). At the same time, the setting of the slide 205 and the limit groove 207 ensures that the roughening strip 204 is always calibrated in the direction of adapting to the beam width, avoiding errors and deviations in operation; the present invention has repeatability and extensibility. Before the preparation of the prefabricated composite beam, it can be judged whether the rough surface prefabricated structure 200 is suitable according to the connection between various parameters. When the prefabricated composite beam is prepared, the mold size can be adjusted according to the size, shape and other adaptability of the composite beam. At the same time, the selective adjustment of the style, quantity and distribution of the roughening strip 204 can also meet the construction requirements of the bonding surface. This flexibility and adaptability make the present invention have high practical value and market promotion prospects.

[0111] Finally, it should be noted that the technical solution disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above-mentioned embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for preparing prefabricated composite beams based on different bonding surfaces, characterized in that The following steps are involved: S1: According to the construction drawings or detailed drawings, check whether the parameters of the stirrups meet the predetermined requirements. If they meet the predetermined requirements, implement step S2; if they do not meet the predetermined requirements, implement step S2'; S2: Select the component mold to directly prepare the prefabricated part of the composite beam, and the joint surface is not roughened; S2': Select a component mold with a rough surface prefabricated structure and simultaneously prepare the prefabricated part of the composite beam and roughen its joint surface; S3: The prefabricated part is transported to the site for installation, and the cast-in-place part is constructed; S4: Complete maintenance work; S5: repeat steps S1, S2 or S2', S3, S4; Wherein: In step S1, the number of stirrups n is checked according to the structural construction drawing or detailed drawing sv , Area of ​​single stirrup A sv , stirrup spacing s sv The beam length L and stirrup yield strength f sv , cast-in-place layer thickness a, beam height h, longitudinal reinforcement tensile yield strength f y , longitudinal reinforcement area A s , effective height of beam section h0, adjustment coefficient of concrete compressive strength α1, width of precast beam b, concrete compressive strength f c Does the relationship between satisfy formula (I): In step S2, according to the designed size and shape of the prefabricated part of the composite beam, a component mold that meets the requirements is assembled and closed; wherein: the component mold includes two bottom frames arranged opposite to each other in the beam width direction, and a fixed-size bottom plate is selectively arranged on the bottom frame, and a rotatable side mold is hinged on the outer side of each of the bottom frames through a hinge seat, and the two are connected by a pull rod, and a concrete pouring mold cavity is formed on the fixed-size bottom plate between the two rotatable side molds through two end mold plates, and reinforcement holes for the longitudinal reinforcement of the beam to pass through are also reserved on the end mold plates.

2. The method for preparing prefabricated composite beams based on different bonding surfaces according to claim 1, characterized in that: The distance between the two bottom frames is adjusted by a telescopic structure.

3. The method for preparing prefabricated composite beams based on different bonding surfaces according to claim 1 or 2, characterized in that: In step S2', when the rough surface is processed by the rough surface prefabricated structure, it should be ensured that the concave-convex depth of the rough surface is not less than 6 mm, and the area of ​​the rough surface is not less than 80% of the area of ​​the bonding surface.

4. The method for preparing prefabricated composite beams based on different joint surfaces according to claim 3, characterized in that: The rough surface prefabricated structure includes a mounting plate arranged according to the length of the beam. The mounting plate is installed above the concrete casting mold cavity of the component mold and can be moved in the direction of the beam width. A strip-shaped through groove that adapts to the length of the beam is opened on the mounting plate. A plurality of lifting components that can adjust the position in the direction of the beam length are arranged in the strip-shaped through groove. The lower end of the lifting component extends into the concrete casting mold cavity and is detachably installed with a roughening strip.

5. The method for preparing prefabricated composite beams based on different joint surfaces according to claim 4, characterized in that: Slideways adapted to the beam width are respectively arranged on the first and last pull rods of the component mold, and the first and last plate ends of the mounting plate are respectively restricted in the corresponding slideways by bolts.

6. The method for preparing prefabricated composite beams based on different joint surfaces according to claim 5, characterized in that: The lifting assembly comprises a lifting screw rod arranged on the roughening strip in the direction of beam height, an adjusting nut is sleeved on the lifting screw rod, and the adjusting nut is placed on the strip-shaped through groove.

7. The method for preparing prefabricated composite beams based on different joint surfaces according to any one of claims 4 to 6, characterized in that: A limiting groove is also provided on the mounting plate and is arranged in parallel with the strip-shaped through groove. A limiting rod is also connected to each of the roughening strips and passes through the limiting groove in the direction of the beam height. The limiting rod is used to cooperate with the lifting assembly to always limit the roughening strip in the direction that adapts to the beam width.

8. The method for preparing prefabricated composite beams based on different joint surfaces according to claim 7, characterized in that: A first scale for indicating the lifting height of the roughening strip in the beam height direction is arranged on the limiting rod, and a second scale for indicating the adjusting position of the roughening strip in the beam length direction is also arranged near the limiting groove.

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