A complex double-layer concrete shell system with indirect prestressing

Abstract

This utility model relates to an indirect prestressed complex double-layer concrete shell system. The upper and lower shells of this complex shell are vertically oriented upwards at their bottoms, with the cantilevered ends approaching horizontal. A concrete rib is installed between the two shell layers. The middle of the shell connects to a horizontal prestressed concrete closed beam, forming a spatial structure. The horizontal closed prestressed beam supports the complex shell, and the application of prestress within the closed beam creates indirect prestress, altering the constraint boundary conditions of the complex shell and changing the distribution and magnitude of internal forces. The prestressing tendons within the closed beam can be arranged in straight lines, broken lines, or curves, and the bonding method of the prestressing tendons can be bonded, unbonded, or loosely bonded. This indirect prestressed double-layer concrete complex shell with a horizontal closed prestressed beam improves both the crack and bending resistance of the component and its deformation performance. Therefore, it is particularly suitable for large-span, large-cantilever shell structures with high deformation and load-bearing capacity.

Description

Technical Field

[0001] This utility model relates to an indirect prestressed complex double-layer concrete shell system. Background Technology

[0002] In recent years, with the improvement of construction technology in my country, the corresponding construction standards have also become increasingly higher. Double-layered concrete shells have also become more diverse. Distinguishing them by stress characteristics: some concrete shells exhibit both the compressive stress characteristics of concrete columns and the tensile stress characteristics of cantilever beams; distinguishing them by form: the centerline of the shell is neither a traditional oblique line nor a quadratic parabola, but rather appears as a complex curve. Furthermore, with excessive cantilever, it is difficult to guarantee the crack resistance and deformation resistance of the components. Summary of the Invention

[0003] This invention aims to provide an indirect prestressed complex double-layer concrete shell, introducing the innovative concept of an indirect prestressed structure. The horizontal closed prestressed beam supports the complex shell, altering the constraint boundary conditions and the distribution and magnitude of internal forces, thereby improving the shell's stress performance and ultimate bearing capacity. This effect of the horizontal closed prestressed beam is called indirect prestressing.

[0004] The closed beam can be a circular ring or a closed beam of arbitrary curve. There can be multiple closed beams. By optimizing the position and number of prestressed closed beams, their stiffness, and the number of prestressing tendons, the distribution and constraint distribution of complex shells can be adjusted and improved, thereby reducing stress distribution and controlling the deformation of complex shells. Using a combination of bonded and unbonded tendons allows for the control of prestress and the adjustment and replacement of unbonded tendons in later stages. Combining loosely bonded and unbonded tendons allows for adjustable, controllable, and replaceable prestressing throughout its entire lifespan, including the construction and service stages, while maintaining higher durability.

[0005] In this invention, the upper and lower shells of the complex shell are vertically oriented upwards, with the cantilevered ends nearly horizontal. Concrete ribs are installed between the two shell layers. The middle of the shell connects to a horizontal prestressed concrete closed beam to form a spatial structure. This complex shell with a horizontal closed prestressed beam improves both the crack and bending resistance of the component and its deformation performance. Therefore, it is particularly suitable for large cantilever structures with high deformation and load-bearing capacity.

[0006] To achieve the above objectives, the present invention adopts the following solution:

[0007] A complex double-layer concrete shell with indirect prestressing consists of an upper shell (1), a lower shell (2), ribs (3), and a closed beam (4). The upper shell (1) and the lower shell (2) are fixed at the bottom, nearly vertical near the fixed end, and nearly horizontal at the end. They are connected to the horizontal prestressed concrete closed beam in the middle.

[0008] The design method for further complex shells is achieved through the following steps:

[0009] 1. An indirect prestressed complex double-layer concrete shell, comprising an upper shell (1), a lower shell (2), ribs (3), and a closed beam (4), wherein the prestressed closed beam (4) has: upper prestressing tendons (5), lower prestressing tendons (6), stirrups (7), upper longitudinal main reinforcement (8), and lower longitudinal main reinforcement (9).

[0010] 2. Furthermore, the centerlines of the upper shell (1) and the lower shell (2) include straight lines, broken lines, and curves;

[0011] 3. Furthermore, the upper prestressing tendon (5) is tensioned only within the closed beam (4), and the lower prestressing tendon (6) is tensioned only within the closed beam (4);

[0012] 4. Furthermore, the arrangement of the upper prestressing tendons (5) within the closed beam (4) includes straight, broken, and curved prestressing tendons;

[0013] 5. Furthermore, the arrangement of the lower prestressing tendons (6) within the closed beam (4) includes straight, broken, and curved prestressing tendons;

[0014] 6. Furthermore, the bonding method of the upper prestressing tendon (5) and the lower prestressing tendon (6) in the closed beam (4) is a bonded, unbonded and loosely bonded prestressing tendon;

[0015] 7. Furthermore, the upper prestressing tendon (5) and the lower prestressing tendon (6) are calculated according to the actual bonding condition of the prestressing tendons as bonded, unbonded and loosely bonded, respectively, during the construction stage, normal use or ultimate bearing calculation.

[0016] By adopting this system, the amount of material used in the structure is reduced by about 15%, making it more economical. Attached Figure Description

[0017] Figure 1 This is an elevation view of the complex shell (1);

[0018] Figure 2 This is a top view of the complex shell (1);

[0019] Figure 3 This is a cross-sectional view of the prestressed closed beam (2); Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings.

[0021] The present invention includes an upper shell (1), a lower shell (2), a rib plate (3), and a closed beam (4). The prestressed closed concrete beam (4) has upper prestressing tendons (5), lower prestressing tendons (6), stirrups (7), upper longitudinal main reinforcement (8), and lower longitudinal main reinforcement (9).

[0022] The centerlines of the upper shell (1) and the lower shell (2) include straight lines, broken lines, and curves.

[0023] The upper prestressing tendon (5) is tensioned only within the closed beam (4), and the lower prestressing tendon (6) is tensioned only within the closed beam (4);

[0024] The arrangement of the upper prestressing tendons (5) within the closed beam (4) includes straight, broken, and curved prestressing tendons;

[0025] The lower prestressing tendons (6) are arranged in the closed beam (4) in the form of straight lines, broken lines, and curved prestressing tendons;

[0026] The bonding method of the upper prestressing tendon (5) and the lower prestressing tendon (6) in the closed beam (4) is unbonded, loosely bonded or bonded prestressing tendons;

[0027] The upper prestressing tendon (5) and the lower prestressing tendon (6) are calculated according to the actual bonding condition of the prestressing tendons during construction, normal use or ultimate bearing calculation, respectively, as bonded, unbonded and loosely bonded.

[0028] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A complex double-layer concrete shell system with indirect prestressing, comprising an upper shell (1), a lower shell (2), ribs (3), and a closed beam (4), wherein the prestressed closed beam (4) has: upper prestressing tendons (5), lower prestressing tendons (6), stirrups (7), upper longitudinal main reinforcement (8), and lower longitudinal main reinforcement (9); characterized in that, The upper and lower shells are vertically upward at the bottom, with the overhanging ends nearly horizontal. A concrete rib is set between the two shells, and the middle of the shell connects with a horizontal prestressed concrete closed beam to form a spatial structure.

2. The indirect prestressed complex double-layer concrete shell system according to claim 1, characterized in that, The centerlines of the upper shell (1) and the lower shell (2) include straight lines, broken lines, and curves.

3. The indirect prestressed complex double-layer concrete shell system according to claim 2, characterized in that, The upper prestressing tendon (5) is tensioned only within the closed beam (4), and the lower prestressing tendon (6) is tensioned only within the closed beam (4).

4. The indirect prestressed complex double-layer concrete shell system according to claim 3, characterized in that, The arrangement of the upper prestressing tendons (5) and the lower prestressing tendons (6) within the closed beam (4) includes straight, broken, and curved prestressing tendons.

5. The indirect prestressed complex double-layer concrete shell system according to claim 4, characterized in that, The bonding methods of the upper prestressing tendon (5) and the lower prestressing tendon (6) in the closed beam (4) are bonded, unbonded and loosely bonded prestressing tendons.

6. The indirect prestressed complex double-layer concrete shell system according to claim 5, characterized in that, The upper prestressing tendon (5) and the lower prestressing tendon (6) are calculated according to the actual bonding condition of the prestressing tendons as bonded, unbonded, and loosely bonded, respectively, during the construction stage, normal use, or ultimate bearing calculation.

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