One-step forming structure of main and secondary beams of PC composite beam and construction method thereof

Abstract

The present invention discloses a one-time forming structure of a main and secondary beam of a PC composite beam, comprising a precast concrete composite beam main beam, a special end mold for a notch, and a special mold for a "cross-shaped" notch. The precast concrete composite beam main beam has a "cross-shaped" notch reserved at the intersection and overlap position of the secondary beams, a horizontal steel bar is arranged in the "cross-shaped" notch, and a protective layer is provided below the "cross-shaped" notch. The special end mold for the notch and the special mold for the "cross-shaped" notch are arranged in the "cross-shaped" notch. The composite beam main beam of the present invention is provided with a one-time pouring of uninterrupted stressed steel bars and concrete, thereby ensuring the integrity of the structural performance of the composite beam main beam, improving construction efficiency, and reducing labor costs. The special mold for the "cross-shaped" notch is adopted, which has flexible installation and adjustable error, reduces the difficulty of the notch manufacturing process, and saves template construction consumption through the template effect of the "cross-shaped" notch, which is conducive to the popularization and application of assembled concrete structures.

Description

Technical Field

[0001] The invention belongs to the field of construction engineering, and particularly relates to a one-step forming structure of a primary and secondary beam of a PC composite beam and a construction method thereof. Background Art

[0002] Prefabricated buildings have developed rapidly with their good economic, environmental and social benefits. Compared with the prefabricated integral shear wall structure system, the prefabricated integral structural frame system has more difficulties in the design and prefabrication stages, especially in the intersection and overlap of the main beam of the prefabricated composite beam and the secondary beam of the composite beam.

[0003] Composite main beams often have a middle notch to facilitate the intersection and overlap with the secondary beams, so as to improve the connection performance and integrity of the overall structure. However, because the notch is located in the middle of the component and is small in size, it is extremely inconvenient to demould and finish the surface. As a result, the notch quality of the prefabricated composite beam is poor, and the installation of the main and secondary beams on site is difficult.

[0004] The existing conventional practice is to separate the main beam and the secondary beam into two parts, and then cast the main and secondary beam overlap section concrete after installation; the other is to use pre-buried threaded sleeves, prefabricate 120mm thick concrete at the bottom of the composite beam main beam, and then install the bolts with anchor plates and tighten them after installation, and cast the concrete in place. Both of these processes require disconnecting the stress reinforcement and horizontal longitudinal reinforcement of the composite beam main beam, which affects the safety performance of the structure. These processes either increase the specifications of the stress reinforcement or use grouting sleeves to anchor the steel bars, which will also increase the construction cost and extend the construction period during the installation process.

[0005] The assembled PC composite beam main and secondary beams combine the structural characteristics of the prefabricated composite beam main beam itself and the advantage of not damaging the stressed steel bars. The two are combined through a special mold to maximize the advantages of the two and avoid related disadvantages. The demand for improving construction efficiency can be effectively solved by the "cross-shaped" notch of the composite beam main and secondary beams. The present invention is proposed based on this demand. Summary of the invention

[0006] In order to solve the above problems, the present invention discloses a one-time forming structure of the main and secondary beams of a PC composite beam and a construction method thereof. At the "cross" intersection and overlap position of the prefabricated composite beam main beam and the secondary beam, a platform for placing the secondary beam of the composite beam is reserved, and the horizontal reinforcement of the main beam is retained. Through the combination of a special mold and an end mold, the side mold is installed on the platform mold, and the concrete is poured in one time to form. The problem that the overall performance of the prefabricated composite beam main beam segmented prefabrication is difficult to guarantee is solved. After the prefabricated composite beam is hoisted, the node concrete is cast at the intersection with the secondary beam, which avoids the secondary formwork after the prefabricated installation of the composite beam main beam segmented, eliminates node leakage, and avoids the problem of affecting the installation efficiency. At the same time, the connection strength after the installation is completed and the advantages of prefabrication technology are brought into play, reducing the impact of manufacturing costs.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A one-step forming structure of a main and secondary beam of a PC composite beam comprises a precast concrete composite beam main beam, a special end mold for a notch, and a special mold for a "cross-shaped" notch. The precast concrete composite beam main beam has a "cross-shaped" notch reserved at the intersection and overlap position of the secondary beams, a horizontal steel bar is arranged in the "cross-shaped" notch, a protective layer is provided under the "cross-shaped" notch, and the special end mold for the notch and the special mold for the "cross-shaped" notch are arranged in the "cross-shaped" notch.

[0009] Preferably, the number of the special end molds for the notch is two, which are symmetrically arranged in the "cross-shaped" notch. A single special end mold for the notch comprises a patterned steel plate, a convex keyway steel block, a side steel plate, and a top steel plate. The patterned steel plate is assembled and welded with the side steel plate and the top steel plate to form a rectangle. The patterned steel plate is flush with the top of the side steel plate, and the bottom is 20 mm longer than the side steel plate. The patterned steel plate is provided with a long slot hole for the horizontal steel bar to pass through. The side steel plate is provided with two positioning holes and one screw hole. The convex keyway steel block is provided with a convex keyway steel block. The number of channel steel blocks is one each, and two convex keyway steel blocks are vertically arranged. The size of the convex keyway steel block is 100*100mm, the thickness is 30mm, and it is chamfered inward at 45°. The convex keyway steel block is tightened and fixed on the inner surface of the patterned steel plate one through screw hole two. The special end mold for the notch is welded and assembled into one. After the main beam steel bar skeleton is put into the mold, the long slot hole is used to pass through the horizontal steel bars of the main beam from top to bottom, and it is positioned and fixed on the side of the main beam through positioning hole two and screw hole one, which is used for the "cross-shaped" notch forming.

[0010] Preferably, the "cross-shaped" slot special mold includes two patterned steel plates, angle steels, and demolding rods. The two patterned steel plates are arranged above the bottom concrete position of the "cross-shaped" slot, and the width of the two patterned steel plates is consistent with the width of the "cross-shaped" slot. The two ends of the angle steel are chamfered 45° and fixed on both sides of the two patterned steel plates, and the side surfaces are flush with the two patterned steel plates. A gap of 1-2 cm is left between the 45° inclined surfaces at both ends of the angle steel and the 45° inclined surfaces of the bottom surface of the special end mold for the slot, and a positioning hole is opened on the side of the angle steel; the bottom of the demolding rod is connected to the two patterned steel plates by threads for demolding the special mold.

[0011] The set of special end molds for the notches described in the present invention are mirror images, each of which is placed in the "cross-shaped" notch with a special mold for the "cross-shaped" notch, and can limit the length, width and height of the "cross-shaped" notch of the column during pouring. The main beam and the secondary beam can be poured at one time when intersecting and overlapping, thereby ensuring the integrity of the structural performance of the main beam of the composite beam, avoiding the problem of poor concrete adhesion caused by segmented prefabrication and segmented installation during construction and the interference between operations between different types of work, thereby improving construction efficiency. In addition, this set of devices is flexible to install and has adjustable errors, thereby reducing the difficulty of the notch manufacturing process and further reducing production costs.

[0012] The precast concrete composite beam main beam refers to a composite component in the assembled frame structure system, which is supported at both ends on columns or walls and receives the force of the secondary beam. It serves as a template for the post-cast concrete composite layer to bear the load during the construction phase and forms an integral composite concrete component with the post-cast concrete layer. The precast concrete composite beam main beam is provided with a "cross-shaped" notch of the secondary beam, and the composite main beam is more convenient for hoisting. At the same time, due to the presence of post-cast concrete, the integrity of the structure is relatively good.

[0013] Preferably, the slot-specific end mold has sufficient rigidity and straightness, and its rough surface is made to meet the design requirement of more than 6mm. The convex keyway steel block on the back of the base steel plate can optimize the concave and convex depth of the end, and the material size meets the drawing requirements of the prefabricated composite beam.

[0014] Preferably, the special mold for the "cross-shaped" slot is "T"-shaped; the special mold for the "cross-shaped" slot is installed in combination with the special end mold for the slot before the side mold of the composite beam is installed, and is fastened to the side mold by bolts at a positioning hole to prevent the concrete at the lower end of the special mold for the "cross-shaped" slot from floating up and leaking, thereby further improving the shape and appearance of the "cross-shaped" slot of the main beam of the precast concrete composite beam.

[0015] Preferably, after the "cross-shaped" notch of the main beam of the precast concrete composite beam is formed and demoulded, a 50*5mm angle steel is provided and connected to one side thereof to improve durability; according to the on-site construction plan, the installation can also be carried out after the precast concrete base plate is hoisted in the building structure.

[0016] Preferably, the flatness of the bottom formwork of the prefabricated truss reinforced concrete composite slab shall not be greater than 2 mm, and the thickness of the MF insulation board is reserved around the side formwork to ensure sufficient supporting strength between the layers during stacking and transportation.

[0017] A method for manufacturing a one-step forming structure of a primary and secondary PC composite beam comprises the following steps:

[0018] (1) First, configure the side formwork of the main beam according to the external dimensions of the prefabricated composite beam main beam in the design drawing, and use a conventional fixed table formwork for the bottom formwork;

[0019] (2) According to the design dimensions of the composite beam main beam, a special end mold for the notch is made; the width dimension of the special end mold for the notch is the same as the width dimension of the main beam, and the height dimension is the main beam height minus the thickness dimension of the notch concrete. A convex keyway steel block of 100*100*30mm is set on the back of the patterned steel plate to increase the depth of the rough surface of the notch, which is convenient for better bonding of new and old concrete.

[0020] (3) Making the special mold for the "cross-shaped" notch. After the steel cage of the composite beam main beam is hoisted to the bottom mold, first install the side mold on one side of the precast concrete composite beam main beam, and install the special end mold for the notch through the horizontal steel bars and the side mold at the notch position. Affix the stop strip to fit the side mold to avoid leakage.

[0021] (4) After the special end mold for the notch is in place, the special mold for the "cross-shaped" notch is installed. The special mold for the "cross-shaped" notch is fixed by bolts through the positioning holes reserved on the installed side mold of the composite beam;

[0022] (5) Install the side formwork on the other side of the main beam of the prefabricated composite beam, adjust the spacing of the extended reinforcement, use a grout stopper to plug the horizontal reinforcement reserved groove on the special end formwork for the notch, and pour concrete;

[0023] (6) After final setting, steam curing is carried out.

[0024] (1) The present invention adds a process for prefabricating the overlapping notches between the main beam and the secondary beam of the composite beam in the assembled frame structure system. The composite beam main beam is poured at one time without disconnecting the stress-bearing steel bars and concrete, thereby ensuring the integrity of the structural performance of the composite beam main beam, avoiding the problem of poor concrete adhesion caused by segmented prefabrication and segmented installation during the construction process and the interference between the operations of different types of work, improving the construction efficiency, reducing the labor cost, and facilitating the popularization and application of assembled concrete structures.

[0025] (2) The present invention adopts a special "cross-shaped" slot mold, which is flexible to install and has adjustable errors, thus reducing the difficulty of the slot manufacturing process, further reducing production costs and improving construction efficiency.

[0026] (3) The present invention eliminates the problems of poor concrete bonding and grout leakage at the joints of the main and secondary beams through the template function of the "cross-shaped" notch. The secondary template matching process after installation in the conventional segmented prefabrication process is eliminated, which saves template construction consumption and is conducive to the promotion and application of prefabricated concrete structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a cross-sectional view of the secondary beam of the present invention;

[0028] Figure 2A three-dimensional view of the "cross-shaped" notch of the present invention;

[0029] Figure 3 It is a three-dimensional view of the assembly of the main and secondary beams of the "cross-shaped" notch of the present invention;

[0030] Figure 4 This is a front view of the special end mold and the special mold in the "cross-shaped" notch of the present invention;

[0031] Figure 5 It is a top view of the special mold for the "cross-shaped" notch of the present invention;

[0032] Figure 6 This is a schematic diagram of installing the special end mold for the notch of the present invention;

[0033] Figure 7 It is a top view of the cooperation between the special end mold and the special mold in the "cross-shaped" notch of the present invention;

[0034] Figure 8 This is a front view of the convex keyway steel block of the present invention;

[0035] Fig. 9 A three-dimensional view of the side mold assembly of the present invention;

[0036] Fig.10 A three-dimensional view of the special mold for the "cross-shaped" notch of the present invention;

[0037] Fig.11 It is a physical diagram of the component construction application of the present invention.

[0038] List of Figure Symbols:

[0039] 1. Main reinforcement, 2. Stirrups, 3. Concrete, 4. Horizontal reinforcement, 5. Special end mold for notch, 6. Special mold for "cross-shaped" notch, 7. "Cross-shaped" notch, 8. Secondary beam of composite beam, 9. Main beam of composite beam, 10. Protective layer, 11. Two patterned steel plates, 12. Angle steel, 13. Demoulding rod, 14. One positioning hole, 15. One patterned steel plate, 16. Side steel plate of special end mold, 17. Two positioning holes, 18. Convex keyway steel block, 19. One screw hole, 20. Long slot hole, 21. Two screw holes, 22. Top steel plate of special end mold, 23. Side mold of main beam. DETAILED DESCRIPTION

[0040] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0041] As shown in the figure, a construction method for a one-step forming structure of a PC composite beam primary and secondary beams of the present invention is firstly to make two special end molds 5, and a horizontal steel bar slot 20 is reserved on the patterned steel plate 15 of the end mold 5 for entering and exiting the two ends of the "cross-shaped" slot 7 after the steel cage is in place, and a positioning hole 17 and a screw hole 19 on the side steel plate 16 of the end mold are used for positioning and fixing with the composite beam side mold 23, and a convex keyway steel block 18 is installed on the patterned steel plate 15 by a bolt 21 on the inner side, such as Figure 1 , 4 As shown; the size of the special end formwork is consistent with the size of the main beam and secondary beam of the composite beam, the side formwork is flat and the stop mortar strip is attached before the formwork to stop the mortar, such as Fig. 9 shown.

[0042] The special mold 6 for making the "cross-shaped" notch is made, the size of the bottom patterned steel plate 11 is consistent with the size of the "cross-shaped" notch 7, and the angle steel 12 is spot welded on both sides to protect the edges. Figure 4 , Figure 5 A positioning hole 14 is opened on the side of the angle steel and fastened to the composite beam side mold 23 through bolts. The side mold is affixed with a stop strip, a mold release agent is applied, and assembled with the side mold. Fig. 9 shown.

[0043] After all the molds are assembled, pour the concrete.

[0044] When the component is cured and reaches the age, the mold is removed. First, the side mold is removed, and then the two special end molds 5 and the "cross-shaped" notch special mold 6 are removed one by one. The mold removal operation is completed. Fig.11 As shown, the horizontal steel bars between the entire "cross-shaped" notch 7 do not need to be disconnected or anchored, and are kept in full-length arrangement. The length, width and height of the notch meet the design standards. The protective layer 10 below has a complete and stable structure. Square grooves (groove marks left by the convex keyway steel block 18) are left at both ends of the "cross-shaped" notch 7 to increase the depth of the rough surface of the notch, which facilitates better bonding of new and old concrete.

[0045] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features.

Claims

1. A one-step forming structure of primary and secondary beams of a PC composite beam, characterized in that: It includes a precast concrete composite beam main beam, a special end mold for notches, and a special mold for "cross-shaped" notches. The precast concrete composite beam main beam has a "cross-shaped" notch reserved at the intersection and overlap of the secondary beams. A horizontal steel bar is arranged in the "cross-shaped" notch. A protective layer is provided under the "cross-shaped" notch. The special end mold for the notch and the special mold for the "cross-shaped" notch are arranged in the "cross-shaped" notch. There are two special end molds for the slot, which are symmetrically arranged in the "cross-shaped" slot. A single special end mold for the slot includes a patterned steel plate, a convex keyway steel block, a side steel plate, and a top steel plate. The patterned steel plate is assembled and welded with the side steel plate and the top steel plate to form a rectangle. The patterned steel plate is flush with the top of the side steel plate, and the bottom is 20mm longer than the side steel plate. The patterned steel plate is provided with a long slot hole for horizontal steel bars to pass through. The side steel plate is provided with two positioning holes and one screw hole. The convex keyway steel block The number is one piece each at the top and bottom. Two convex keyway steel blocks are vertically arranged. The size of the convex keyway steel block is 100*100mm, the thickness is 30mm, and the inward chamfer is 45°. The convex keyway steel block is tightened and fixed on the inner surface of the patterned steel plate one through the screw hole two. The special end mold for the notch is welded and assembled into one. After the main beam steel bar skeleton is put into the mold, the long slot hole is used to pass through the horizontal steel bar of the main beam from top to bottom, and it is positioned and fixed on the side of the main beam through the positioning hole two and the screw hole one, which is used for the "cross-shaped" notch forming; The "cross-shaped" slot special mold includes two patterned steel plates, angle steels, and demoulding rods. The two patterned steel plates are arranged above the bottom concrete position of the "cross-shaped" slot. The width of the two patterned steel plates is consistent with the width of the "cross-shaped" slot. The two ends of the angle steel are chamfered 45° and fixed on both sides of the two patterned steel plates. The side surfaces are flush with the two patterned steel plates. A gap of 1-2 cm is left between the 45° inclined surfaces at both ends of the angle steel and the 45° inclined surfaces of the bottom surface of the special end mold for the slot. A positioning hole is opened on the side of the angle steel. The bottom of the demoulding rod is connected to the two patterned steel plates by threads for demoulding of the special mold.

2. The one-step forming structure of the primary and secondary beams of a PC composite beam according to claim 1 is characterized in that: After the "cross-shaped" notch of the main beam of the precast concrete composite beam is formed and demoulded, a 50*5mm angle steel is set and connected to one side thereof.

3. The method for manufacturing a one-step forming structure of a primary and secondary beam of a PC composite beam according to claim 1, characterized in that: The following steps are involved: (1) First, configure the side formwork of the main beam according to the external dimensions of the prefabricated composite beam main beam in the design drawing, and use a conventional fixed table formwork for the bottom formwork; (2) According to the design dimensions of the composite beam main beam, a special end mold for the notch is made; the width dimension of the special end mold for the notch is the same as the width dimension of the main beam, and the height dimension is the height of the main beam minus the thickness dimension of the notch concrete. A convex keyway steel block with a size of 100*100*30mm is set on the back of the patterned steel plate to increase the depth of the rough surface of the notch, so as to facilitate better bonding of the new and old concrete. (3) Making the special mold for the "cross-shaped" notch. After the reinforcement cage of the composite beam main beam is hoisted to the bottom mold, first install the side mold on one side of the precast concrete composite beam main beam, and install the special end mold for the notch through the horizontal reinforcement and the side mold at the notch position. Affix the stop strip to fit the side mold to avoid leakage. (4) After the special end mold for the notch is in place, the special mold for the "cross-shaped" notch is installed. The special mold for the "cross-shaped" notch is fixed by bolts through the positioning holes reserved on the installed side mold of the composite beam; (5) Install the side formwork on the other side of the main beam of the prefabricated composite beam, adjust the spacing of the extended reinforcement, use a grout stopper to plug the horizontal reinforcement reserved groove on the special end formwork for the notch, and pour concrete; (6) After final setting, steam curing is carried out.

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