Prefabricated cast-in-place laminated integral beam

Abstract

The embodiment of the utility model discloses a prefabricated cast-in-place laminated integral beam, in the specific implementation mode, the prefabricated cast-in-place laminated integral beam is composed of two prefabricated concrete beams and a cast-in-place laminated part, each prefabricated concrete beam is composed of an upper web and a lower flange, and the lower flanges of the two prefabricated concrete beams are in direct contact. The two prefabricated concrete beams are spliced and enclosed to form a construction formwork for concrete pouring of the cast-in-place laminated part, stirrups of the prefabricated concrete beams extend out of the top face of the web and the top face of the lower flange close to the cast-in-place laminated part and then extend upwards to the position below the top face of the prefabricated cast-in-place laminated integral beam, and waist drag hooks of the prefabricated concrete beams are completely located in the web. According to the implementation mode, the self weight of the prefabricated beam of a common frame beam in a building can be controlled to be below 6 tons, the hoisting efficiency is high, the connection integrity of the prefabricated part and the cast-in-place part is good, meanwhile, when the prefabricated beam is manufactured, a mold and an exposed rib do not interfere with each other, mold removal is easy, the mold turnover frequency can be greatly increased, and the mold amortization cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of construction, relates to prefabricated concrete, and particularly relates to a prefabricated cast-in-place laminated integral beam. Background Art

[0002] Concrete frame structures often use precast concrete beams to achieve industrialized construction. The self-weight of precast concrete beams has a great impact on the hoisting organization at the construction site, especially for buildings with large floor loads. In order to meet the requirements of load-bearing and earthquake resistance, the cross-sectional size of the frame beam is large. The existing technology controls the self-weight of a single precast beam by using U-shaped cross-section precast beams or precast beams in pairs. However, the above method usually has the following technical problems:

[0003] First, the U-shaped prefabricated beam has a significant weight reduction effect, but a placeholder mold is required to form the U-shaped section. The mold for making the prefabricated beam is relatively complex and difficult to remove.

[0004] Second, the frame beams formed by the double precast beams are only connected by cast-in-place concrete within the height range of the floor slab, and the integrity of the frame beams is poor, which is not conducive to the stress of the torsion frame beams;

[0005] Third, in order to improve the integrity of the precast beam and the cast-in-place part, the precast beam extends out many and complex stirrups. The precast beam manufacturing mold needs to have reinforcement grooves to match the extended stirrups, which weakens the rigidity of the manufacturing mold. The mold has a small turnover number, high amortization cost, and is easily damaged when dismantling the mold. Utility Model Content

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the utility model proposes a prefabricated cast-in-place laminated integral beam, which can control the deadweight of the prefabricated beam of the common frame beam in the building to less than 6 tons, and the connection integrity of the prefabricated and cast-in-place parts is good. At the same time, it avoids one or more problems of the prior art such as complex prefabricated beam molds, ribs affecting mold stiffness and disassembly, high mold amortization costs, poor beam integrity and torsional resistance, etc.

[0007] Some embodiments of the utility model provide a prefabricated cast-in-place laminated integral beam, which is composed of two prefabricated concrete beams and a cast-in-place laminated part. The prefabricated concrete beam is prefabricated with concrete and steel bars or prestressed steel strands. The two prefabricated concrete beams are assembled and enclosed at the lower part of the prefabricated cast-in-place laminated integral beam to form a construction template for pouring concrete of the cast-in-place laminated part. The concrete part of the prefabricated concrete beam is composed of an upper web and a lower flange, the lower flange is connected to the bottom of the web, and the lower flange extends out of the web toward the prefabricated cast-in-place The width of the vertical centerline of the cross section of the laminated integral beam is 7 to 40 cm. The lower flanges of the two precast concrete beams are in direct contact at the vertical centerline of the cross section of the precast cast-in-place laminated integral beam. The cast-in-place overlapping parts are continuously distributed on the web enclosed area and the top surface of the web of the two precast concrete beams. The stirrups of the precast concrete beam extend through the top surface of the web and the top surface of the lower flange close to the cast-in-place overlapping part, and then extend upward to under the top surface of the precast cast-in-place laminated integral beam. The waist hook of the precast concrete beam is completely located in the web.

[0008] Specifically, the width of the web of the precast concrete beam is 15 to 30 cm, the gap between the top surface of the web and the bottom surface of the floor slab is 0 to 1 cm after being installed in place in the overall building, and the height of the lower flange is 7 to 20 cm.

[0009] In particular, the stirrups of the precast concrete beam extending from the top surface of the lower flange near the cast-in-place overlapped portion are independent limbs, which are not connected to the remaining stirrups of the precast concrete beam within the cast-in-place overlapped portion, and a hook is provided at the upper end of the independent limb.

[0010] In some embodiments, the stirrups of the precast concrete beam are continuous closed stirrups, the starting section of the continuous closed stirrups is an independent limb, and the end section is bent and anchored in the web of the precast concrete beam.

[0011] In some embodiments, the stirrups of the precast concrete beam are composed of ordinary closed stirrups and L-shaped hooks. The ordinary closed stirrups are arranged along the periphery of the web, the vertical edge of the L-shaped hook is an independent limb, and the horizontal edge of the L-shaped hook extends along the bottom edge of the lower flange and is bent upward and anchored.

[0012] Optionally, the top surface of the web of the precast concrete beam and the top surface of the lower flange close to the cast-in-place overlapping part are natural casting surfaces.

[0013] In some embodiments, a groove group is provided on the vertical side of the web of the precast concrete beam in contact with the cast-in-place overlapping part, and the groove group consists of a series of grooves orthogonal to each other, wherein a part of the grooves are arranged along the length direction of the precast concrete beam.

[0014] Specifically, the orthogonal grooves are arranged in groups and spaced apart along the length direction of the precast concrete beam, the groove opening width is 10 to 15 cm, the net spacing between adjacent grooves is 10 to 15 cm, the length of the grooves parallel to the length direction of the precast concrete beam is 80 to 150 cm, and the grooves perpendicular to the length direction of the precast concrete beam are continuous along the web height direction.

[0015] In some embodiments, a beam iron is provided in the corner and hook of the stirrups of the precast concrete beam extending into the cast-in-place overlapping part, and an upper hook is provided on the top surface of the cast-in-place overlapping part and at a position corresponding to the stirrups extending from the precast concrete beam. The upper hook intersects with the stirrups of the two precast concrete beams to form the outer stirrups of the precast cast-in-place laminated integral beam.

[0016] In some embodiments, the beam bottom iron of the prefabricated cast-in-situ laminated integral beam is arranged at the lower part of the prefabricated concrete beam, and the beam bottom iron is a steel bar or a prestressed steel strand.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] (1) The utility model can control the deadweight of precast concrete beams, which are common frame beams in buildings, to less than 6 tons, making it easy to use a large tower crane for on-site hoisting, with high hoisting efficiency and low cost.

[0019] (2) The prefabricated and cast-in-place parts of the prefabricated cast-in-place laminated integral beam of the utility model are connected by stirrups and the cast-in-place part is almost distributed within the height range of the cross section of the prefabricated cast-in-place laminated integral beam. The prefabricated cast-in-place laminated integral beam has good integrity and its torsional performance is close to that of the traditional integral cast-in-place beam.

[0020] (3) Under the premise of ensuring the connection strength between the prefabricated and cast-in-place parts, the utility model can achieve the goal of preventing the mold and the reinforcement from interfering with each other during the production of prefabricated concrete beams, making it easy to dismantle the mold, greatly improving the mold turnover rate and reducing the mold amortization cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 It is a schematic diagram of the cross-sectional structure of some embodiments of the prefabricated cast-in-situ laminated integral beam in the utility model.

[0023] Figure 2 for Figure 1 Schematic diagram of the 3D structure of the precast concrete beam, with one end shown in perspective.

[0024] Figure 3 yes Figure 2 Cross-sectional view of section AA.

[0025] Figure 4 for Figure 3 Schematic diagram of the structure of stirrups in precast concrete beams.

[0026] Figure 5 It is a schematic diagram of the exploded structure of the stirrups of the precast concrete beams of other embodiments of the precast cast-in-situ laminated integral beams in the utility model.

[0027] In the figure: 1-precast concrete beam; 11-stirrup; 111-independent limb; 112-ordinary closed stirrup; 113-L-shaped hook; 12-beam lower iron; 13-beam waist reinforcement; 14-beam upper iron; 15-waist hook; 2-web; 21-groove; 3-lower flange; 4-cast-in-place overlapping part; 41-upper hook; 5-floor slab. DETAILED DESCRIPTION

[0028] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. On the contrary, the embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0030] The utility model provides a prefabricated cast-in-place laminated integral beam, which has the advantages of light weight of prefabricated concrete beams, tower crane lifting without the need for car cranes to lift them up to the building, and high lifting efficiency. At the same time, it can realize support-free construction of building beams and floor slabs, avoiding the shortcomings of the prior art prefabricated concrete beams such as poor weight reduction effect, complex molds, poor torsional performance, and difficulty in matching the prefabricated beam reinforcement with the mold.

[0031] refer to Figure 1 to Figure 3The utility model prefabricated cast-in-place laminated integral beam is composed of two prefabricated concrete beams 1 and a cast-in-place superimposed part 4. The prefabricated concrete beam 1 is prefabricated with concrete and steel bars or prestressed steel strands. The two prefabricated concrete beams 1 are assembled and enclosed at the lower part of the prefabricated cast-in-place laminated integral beam to form a construction template for pouring concrete of the cast-in-place superimposed part 4. Among them, the concrete part of the prefabricated concrete beam 1 is composed of an upper web 2 and a lower flange 3. The lower flange 3 is connected to the bottom of the web 2, and the lower flange 3 extends out of the web 2 toward the horizontal direction of the prefabricated cast-in-place laminated integral beam. The width of the vertical centerline extension of the cross-section is 7 to 40 cm. The lower flanges 3 of the two precast concrete beams 1 are directly in contact at the vertical centerline of the cross-section of the precast cast-in-place laminated integral beam. The cast-in-place overlapping part 4 is continuously distributed on the web 2 enclosed area and the top surface of the web 2 of the two precast concrete beams 1. The stirrups 11 of the precast concrete beam 1 extend through the top surface of the web 2 and the top surface of the lower flange 3 close to the cast-in-place overlapping part 4, and then extend upward to below the top surface of the precast cast-in-place laminated integral beam. The waist hook 15 of the precast concrete beam 1 is completely located in the web 2. By enclosing the lower flanges 3 of the two precast concrete beams 1, the range of the cast-in-place overlapping part 4 connecting the two precast concrete beams 1 is greatly expanded under the premise of reducing the self-weight of the precast concrete beams 1, and the stirrups connecting the precast concrete beams 1 and the cast-in-place overlapping part 4 are extended from the web 2 and the top surface of the lower flange 3 of the precast concrete beam 1, avoiding the vertical side of the web 2 of the precast concrete beam 1. It is ensured that the precast concrete beam 1 can be manufactured by pouring concrete in stages within the range of the lower flange 3 and the web 2, avoiding the situation where the extended stirrups interfere with the precast concrete beam mold and the need to open a reinforcement groove for coordination, thereby improving the manufacturing efficiency of the precast concrete beam and reducing the mold amortization cost.

[0032] In the description of the present invention, it should be noted that the terms "upper part", "lower part", "top surface", "bottom surface", "length direction" and "height direction" are based on the orientation or position relationship in which the prefabricated cast-in-place laminated integral beam of the present invention is usually placed when in use. The above terms restrict the orientation and structure of the prefabricated cast-in-place laminated integral beam of the present invention.

[0033] refer to Figure 1 to Figure 4 , showing the structural schematic diagram of some embodiments of the prefabricated cast-in-situ laminated integral beam of the utility model. Figure 1 to Figure 3As shown, the precast cast-in-place laminated integral beam is composed of two precast concrete beams 1 and a cast-in-place laminated part 4. The precast concrete beam 1 is prefabricated with concrete and steel bars or prestressed steel strands. The concrete part of the precast concrete beam 1 is composed of an upper web 2 and a lower flange 3. The lower flange 3 is connected to the bottom of the web 2. The lower flange 3 extends out of the web 2 toward the vertical center line of the cross section of the precast cast-in-place laminated integral beam by a width of 7 to 40 cm. The width of the web 2 is 15 to 30 cm. After being installed in place in the integral building, the top surface of the web 2 is aligned with the floor slab. The gap between the bottom surfaces of 5 is 0-1 cm, the height of the lower flange 3 is 7-20 cm, the lower flanges 3 of the two precast concrete beams 1 are in direct contact at the vertical center line of the cross section of the precast cast-in-place laminated integral beam, and the two precast concrete beams 1 and the upper floor slab 5 enclose a construction template for pouring concrete of the cast-in-place overlapping part 4, thereby realizing the support-free and formwork-free construction of the cast-in-place overlapping part 4 of the precast cast-in-place laminated integral beam, and the cast-in-place overlapping part 4 is continuously distributed on the enclosed area of ​​the web 2 of the two precast concrete beams 1 and the top surface of the web 2.

[0034] See also Figure 3 The beam underrail 12 of the precast cast-in-place laminated integral beam is arranged at the lower part of the precast concrete beam 1. When the span and load of the precast cast-in-place laminated integral beam are within the normal range, the beam underrail 12 is made of steel bars; when the span and load of the precast cast-in-place laminated integral beam are large, the beam underrail 12 is made of prestressed steel strands, or a combination of prestressed steel strands and steel bars. Figure 1 to Figure 4 , each vertical limb of the stirrup 11 extends through the top surface of the web 2 and the top surface of the lower flange 3 close to the cast-in-place overlapping part 4, and extends upward to below the top surface of the precast cast-in-place laminated integral beam, wherein the stirrup 11 of the precast concrete beam 1 extending from the top surface of the lower flange 3 close to the cast-in-place overlapping part 4 is an independent limb 111, and the independent limb 111 is not connected with the remaining limbs of the stirrup 11 of the precast concrete beam 1 within the range of the cast-in-place overlapping part 4, and a hook is arranged at the upper end of the independent limb 111. As an example, a 180° hook is adopted for the hook; within the range of the web 2 of the precast concrete beam 1, a beam waist reinforcement 13 and a waist hook 15 are arranged in accordance with the requirements of the current structural design specifications, wherein the waist hook 15 is completely located in the web 2 and does not extend from the vertical side of the web 2. By controlling the extension position and form of the stirrups 11 of the precast concrete beam 1, it is ensured that during the production process of the precast concrete beam 1, the side mold of the mold does not have a reinforcement groove, and the concrete of the precast concrete beam 1 is cast in batches by pouring concrete in the split mold, the lower flange 3 and the web 2. At the same time, an unclosed space is formed between the independent limb 111 and the web 2. The width of the lower flange 3 extending from the web 2 to the vertical center line of the cross section of the precast cast-in-place laminated integral beam is not less than 7 cm, which can ensure sufficient operating space for hoisting, installing and removing the side mold in the vertical direction, thereby improving efficiency. In particular, referring to Figure 3 , Figure 4The stirrups 11 of the precast concrete beam 1 are continuous closed stirrups, and the starting section of the continuous closed stirrups is an independent limb 111. The continuous closed stirrups are continuously formed by multiple bendings using a stirrup bending machine from the starting section, and the end is bent and anchored in the web 2 of the precast concrete beam 1, wherein the end hook is arranged upward and does not cross the vertical limb of the stirrup 11 on the side of the web 2 close to the cast-in-place overlapping part 4, so as to facilitate the insertion of the beam bottom iron 12 through the opening position.

[0035] refer to Figure 1 The beam iron 14 is arranged on the top of the cast-in-place overlapped part 4, wherein a beam iron 14 is arranged in the corner and the hook of the stirrup 11 of the precast concrete beam 1 extending into the cast-in-place overlapped part 4, so as to form a truss mechanism during the shearing process of the precast cast-in-place laminated integral beam, ensuring that the stirrup 11 passes through the precast concrete beam 1 and each vertical limb of the cast-in-place overlapped part 4 to efficiently participate in the shearing work, thereby improving the overall force performance of the precast cast-in-place laminated integral beam; on the top surface of the cast-in-place overlapped part 4 An upper hook 41 is set at a position corresponding to the stirrup 11 extending out of the precast concrete beam 1. The upper hook 41 intersects with the stirrups 11 of the two precast concrete beams 1 to form the outer stirrups of the precast cast-in-place laminated integral beam. As an example, a 135° bend hook is set at the beam end of the upper hook 41. The upper hook 41 and the stirrup 11 are combined to form an integral stirrup, which helps to simplify on-site construction. During the actual construction process, the upper hook 41 can be tied and positioned and then the iron 14 on the beam at the corners on both sides can be passed through.

[0036] In addition to the stirrups 11 that penetrate the precast concrete beam 1 and the cast-in-place overlapped part 4, which directly affect the mechanical integrity of the precast cast-in-place laminated integral beam, the shear resistance of the precast concrete of the precast concrete beam 1 and the cast-in-place concrete of the cast-in-place overlapped part 4 also has a significant impact on the mechanical integrity of the precast cast-in-place laminated integral beam. Considering both mechanical performance and construction technology, see Figure 2During the production process of the precast concrete beam 1, the top surfaces of the web 2 and the lower flange 3 are open to facilitate the pouring of concrete. The top surface of the web 2 of the precast concrete beam and the top surface of the lower flange 3 close to the cast-in-place overlapping part 4 are designed as natural casting surfaces. The natural casting surface has a certain roughness and surface unevenness. After the cast-in-place overlapping part 4 is formed, a new and old concrete bonding surface with a certain shear strength is formed at the position of the natural casting surface. The stirrups 11 of the precast concrete beam 1 extending out of the natural casting surface can control the shear slip of the natural casting surface during the stress of the precast cast-in-place laminated integral beam; for the vertical side surface where the web 2 of the precast concrete beam 1 contacts the cast-in-place overlapping part 4, in order to improve the processing efficiency of the precast concrete beam 1, no steel bars extend out of the vertical side surface, and a groove group is arranged on the vertical side surface, which is composed of a series of grooves 21 orthogonal to each other, wherein a part of the grooves 21 are arranged along the length direction of the precast concrete beam 1, and another part of the grooves 21 are arranged along the web 2 The grooves 21 are arranged in the height direction, and the grooves 21 in different directions and orthogonal are arranged in groups and spaced apart along the length direction of the precast concrete beam 1. The opening width of the grooves 21 is 10-15 cm, and the net spacing between adjacent grooves 21 is 10-15 cm. The length of the grooves 21 parallel to the length direction of the precast concrete beam 1 is 80-150 cm. The grooves 21 perpendicular to the length direction of the precast concrete beam 1 pass through the height direction of the web 2. After pouring the cast-in-place concrete of the cast-in-place overlapping part 4, a series of shear keys in two orthogonal directions will be formed on the vertical side surface where the web 2 of the precast concrete beam 1 contacts the cast-in-place overlapping part 4, which can improve the shear slip resistance in two directions of the vertical side surface where the web 2 of the precast concrete beam 1 contacts the cast-in-place overlapping part 4 during the stress process of the precast cast-in-place laminated integral beam, and improve the collaborative working performance of the precast concrete beam 1 and the cast-in-place overlapping part 4 of the precast cast-in-place laminated integral beam. At the same time, the grooves 21 can be directly formed by mold placement, which is easy to manufacture.

[0037] See next Figure 5 . Figure 5 Schematic diagram of the exploded structure of the stirrups of precast concrete beams of other embodiments of precast cast-in-place laminated integral beams. Figure 5 As shown, the stirrups 11 of the precast concrete beam 1 are composed of ordinary closed stirrups 112 and L-shaped hooks 113. The arrangement in the precast concrete beam 1 is similar to that in FIG. Figure 3The continuous closed stirrups in are basically the same, wherein the ordinary closed stirrups 112 are arranged along the periphery of the web 2, the vertical side of the L-shaped hook 113 is an independent limb 111, and a 180° hook is arranged at the upper end, and the horizontal side of the L-shaped hook 113 is extended along the bottom edge of the lower flange 3 and then bent upward and anchored, and the L-shaped hook 113 forms an enclosure constraint on the beam bottom iron 12 within the range of the lower flange 3. Compared with the continuous closed stirrups, the combination of ordinary closed stirrups 112 and L-shaped hooks 113 has lower requirements on stirrup processing equipment on the basis of ensuring the force performance, but the amount of steel used is increased. At the same time, the 135° hook at the corner of the ordinary closed stirrup 112 will cause certain interference to the installation of the beam bottom iron 12. In actual engineering, the stirrup form can be determined according to the performance of the stirrup processing equipment.

[0038] In summary, in the present invention, the proportion of cast-in-place concrete connecting the precast concrete beams is expanded by optimizing the cross-sectional form of the precast concrete beams, the reinforcement method and the structure of the interface between the new and old concrete. On the basis of reducing the self-weight of the precast concrete beams, the coordinated force-bearing performance of the precast concrete beams and the cast-in-place overlapping parts in the precast cast-in-place laminated integral beams is improved. The precast cast-in-place laminated integral beams have good integrity, especially the torsional performance is significantly better than the existing technology. At the same time, it avoids the shortcomings of the existing technology such as complex precast beam molds, reinforcement affecting mold stiffness and disassembly, and high mold amortization costs.

[0039] The above description is only some preferred embodiments of the utility model and an explanation of the technical principles used. Those skilled in the art should understand that the disclosure scope involved in the embodiments of the utility model is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in the embodiments of the utility model (but not limited to) to form a technical solution.

Claims

1. Prefabricated cast-in-place laminated integral beam, consisting of two prefabricated concrete beams and a cast-in-place superimposed part, the prefabricated concrete beam is prefabricated with concrete and steel bars or prestressed steel strands, the two prefabricated concrete beams are assembled and enclosed at the bottom of the prefabricated cast-in-place laminated integral beam to form a construction template for pouring concrete of the cast-in-place superimposed part, characterized in that: The concrete part of the precast concrete beam is composed of an upper web and a lower flange, the lower flange is connected to the bottom of the web, the width of the lower flange extending from the web to the vertical center line of the cross section of the precast cast-in-place laminated integral beam is 7 to 40 cm, the lower flanges of the two precast concrete beams are directly in contact at the vertical center line of the cross section of the precast cast-in-place laminated integral beam, and the cast-in-place overlapped parts are continuously distributed on the web enclosed area and the top surface of the web of the two precast concrete beams; The stirrups of the precast concrete beam extend through the top surface of the web and the top surface of the lower flange close to the cast-in-place overlapping part and then extend upward to below the top surface of the precast cast-in-place laminated integral beam. The waist hook of the precast concrete beam is completely located in the web.

2. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: The width of the web of the precast concrete beam is 15 to 30 cm. After installation in the overall building, the gap between the top surface of the web and the bottom surface of the floor slab is 0 to 1 cm, and the height of the lower flange is 7 to 20 cm.

3. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: The stirrups of the precast concrete beam extending from the top surface of the lower flange near the cast-in-place overlapping part are independent limbs. The independent limbs are not connected with the remaining limbs of the stirrups of the precast concrete beam within the cast-in-place overlapping part, and a hook is provided at the upper end of the independent limb.

4. The prefabricated cast-in-situ laminated integral beam according to claim 3, characterized in that: The stirrups of the precast concrete beam are continuous closed stirrups. The starting section of the continuous closed stirrups is an independent limb, and the end is bent and anchored in the web of the precast concrete beam.

5. The prefabricated cast-in-situ laminated integral beam according to claim 3, characterized in that: The stirrups of the precast concrete beam are composed of ordinary closed stirrups and L-shaped hooks. The ordinary closed stirrups are arranged along the periphery of the web. The vertical edge of the L-shaped hook is the independent limb. The horizontal edge of the L-shaped hook extends along the bottom edge of the lower flange and is bent upward and anchored.

6. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: The top surface of the web of the precast concrete beam and the top surface of the lower flange close to the cast-in-place overlapping part are natural casting surfaces.

7. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: A groove group is arranged on the vertical side surface where the web of the precast concrete beam contacts the cast-in-place overlapping part. The groove group consists of a series of grooves orthogonal to each other, and a part of the grooves are arranged along the length direction of the precast concrete beam.

8. The prefabricated cast-in-situ laminated integral beam according to claim 7, characterized in that: The orthogonal grooves are arranged in groups and spaced apart along the length direction of the precast concrete beam. The groove opening width is 10 to 15 cm, the net spacing between adjacent grooves is 10 to 15 cm, the length of the grooves parallel to the length direction of the precast concrete beam is 80 to 150 cm, and the grooves perpendicular to the length direction of the precast concrete beam are continuous along the web height direction.

9. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: The stirrups of the precast concrete beam extend into the corners and hooks of the cast-in-place overlapping part, and an upper hook is arranged on the top surface of the cast-in-place overlapping part and at a position corresponding to the stirrups extending from the precast concrete beam. The upper hook intersects with the stirrups of the two precast concrete beams to form the outer stirrups of the precast cast-in-place laminated integral beam.

10. The prefabricated cast-in-situ laminated integral beam according to claim 1, characterized in that: The beam underpinnings of the prefabricated cast-in-place laminated integral beam are arranged at the lower part of the prefabricated concrete beam, and the beam underpinnings are steel bars or prestressed steel strands.

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