Front upper and lower cross beam system suitable for rear fulcrum hanging basket of PC cable-stayed bridge with ultra-wide variable-width Pi-shaped beam

Abstract

The utility model discloses a front upper and lower cross beam system suitable for a rear fulcrum hanging basket of a PC cable-stayed bridge with an ultra-wide variable-width Pi-shaped beam. Characterized in that; the system comprises a main truss, a front upper cross beam, a suspender and a front lower cross beam, the main truss is of a double-truss triangular truss structure and is transversely arranged to be tightly matched with the position of a pi-shaped beam main longitudinal rib, and a stable rigid supporting framework is formed. The front upper cross beam is erected between the two main trusses, a low-section steel beam is adopted to replace a traditional truss form, the suspenders are intensively arranged in corresponding areas of the main longitudinal ribs under the main trusses, a linear force transmission path of the main trusses, the suspenders and the main longitudinal ribs is formed, and the front lower cross beam is connected through the suspenders. According to the rear fulcrum hanging basket, the problems that due to the fact that the span of a front upper cross beam is too large, a traditional rear fulcrum hanging basket (1) is forced to adopt an ultrahigh-section profile steel or truss structure, the overall gravity center of the hanging basket moves upwards, and the stability is poor when the hanging basket walks in a widening section and loads are unbalanced are solved; and (2) the problems of non-uniform force transmission of the upper cross beam, fuzzy load force transmission path, poor overall rigidity performance and incapability of meeting the construction requirements of the ultra-wide and variable-width Pi-shaped main beam due to excessive suspenders are solved.

Description

Technical Field

[0001] This utility model relates to the field of cable-stayed bridge construction, specifically a system for the upper and lower crossbeams in front of the hanging basket at the rear support of an ultra-wide variable-width π-shaped PC cable-stayed bridge. Background Technology

[0002] In the construction of ultra-wide and variable-width π-shaped PC cable-stayed bridges, due to the unique double-longitudinal rib external structure and ultra-wide and variable-width characteristics of the π-shaped main girder, traditional hanging baskets need to adopt a large-spacing main truss layout to match the main girder size, resulting in a sharp increase in the span of the front upper and lower crossbeams. To meet the stiffness requirements, the upper crossbeam needs to adopt an ultra-high section or even a truss structure to meet the stiffness requirements, causing the overall center of gravity of the hanging basket to shift upward, resulting in poor construction stability and a risk of overturning, especially when the stress is uneven in the variable-width section.

[0003] Furthermore, traditional rear-support hanging baskets typically employ a dense suspension rod system to distribute loads, but the excessive number of rods leads to complex and unclear force transmission paths. Loads cannot be effectively transferred to high-load-bearing areas such as the main longitudinal ribs of the π-shaped beam, instead concentrating in the middle section where lateral stiffness is weaker, causing stress concentration and even cracking of the diaphragms. In summary, the existing rigid structural design of rear-support hanging baskets lacks targeted optimization for the unique stress characteristics of the π-shaped beam (strong double main longitudinal ribs, weak middle section), resulting in poor stability and inefficient force transmission under ultra-wide and variable-width conditions, failing to meet the stringent requirements for construction accuracy and safety of ultra-wide and variable-width π-shaped main beams. Utility Model Content

[0004] Therefore, in order to solve the above-mentioned shortcomings, this utility model provides a front upper and lower crossbeam system for the rear support hanging basket of an ultra-wide and variable-width π-shaped PC cable-stayed bridge; it solves the problems of the traditional rear support hanging basket (1) being forced to adopt ultra-high cross-section steel or truss structure due to the large span of the front upper crossbeam, which causes the overall center of gravity of the hanging basket to shift upward, resulting in instability when traveling in the variable-width section and under load eccentricity; (2) the excessive number of hangers causing uneven force transmission of the upper crossbeam, unclear load transmission path and poor overall stiffness performance, which cannot meet the construction requirements of ultra-wide and variable-width π-shaped main beams.

[0005] This utility model is implemented by constructing a front upper and lower crossbeam system for the rear support hanging basket of an ultra-wide variable-width π-shaped beam PC cable-stayed bridge, characterized in that:

[0006] The aforementioned front upper and lower crossbeam system comprises a main truss, a front upper crossbeam, a hanger, and a front lower crossbeam; the main truss adopts a double triangular truss structure, and its transverse arrangement closely matches the position of the main longitudinal ribs of the π-shaped beam, forming a stable rigid support frame;

[0007] The front upper crossbeam is erected between the two main trusses. It uses a low-section steel beam instead of the traditional truss form, which greatly reduces the overall center of gravity of the hanging basket and improves its anti-overturning stability.

[0008] The hangers are concentrated in the area corresponding to the main longitudinal rib directly below the main truss, forming a straight force transmission path of "main truss → hanger → main longitudinal rib". The hangers are connected to the front lower crossbeam, which adopts a truss structure to meet the deflection control requirements of ultra-wide span.

[0009] This utility model has the following advantages: This patent, through optimized structural design and structural system reconstruction, possesses the following advantages:

[0010] (1) Using steel profiles as the upper front crossbeam and a truss structure with a high center of gravity as the lower front crossbeam, the center of gravity of the hanging basket is lowered as a whole. This layout greatly enhances the structural stability of the hanging basket while meeting the same load-bearing requirements, and fundamentally solves the risks of high center of gravity and poor construction stability caused by high cross-section and truss upper crossbeam.

[0011] (2) The length of the front upper crossbeam is significantly shorter than that of the traditional rear support hanging basket, and it only needs to span two main trusses. This design breakthrough allows the upper crossbeam to directly use standardized steel components, which not only reduces the processing difficulty, but also directly reduces the amount of steel used and saves material costs;

[0012] (3) By simplifying and optimizing the position of the suspender system, the intermediate redundant suspenders are completely eliminated, and only the key force transmission suspenders in the corresponding area of ​​the main longitudinal rib are retained, so that the load is transmitted in a straight line along the path of "main truss → suspender → main longitudinal rib", thus completely eliminating the force transmission ambiguity problem caused by traditional multiple suspenders;

[0013] (4) The significant reduction in the number of hangers simultaneously reduces steel consumption and installation complexity, while the optimization of the force transmission path further reduces the local stress of the front upper crossbeam and extends the service life of the structure. Attached Figure Description

[0014] Figure 1 This is a front view of the front upper and lower crossbeam system structure;

[0015] Figure 2 This is a side view of the front upper and lower crossbeam system structure. Detailed Implementation

[0016] The following will be combined with the appendix Figures 1-2 This utility model will be described in detail, and the technical solutions in the embodiments of this utility model will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0017] This utility model provides a system for the upper and lower crossbeams in front of the hanging basket at the rear support of an ultra-wide variable-width π-type beam PC cable-stayed bridge, such as... Figures 1-2As shown, it can be implemented in the following manner;

[0018] The front upper and lower crossbeam system described in this application comprises a main truss 1, a front upper crossbeam 2, a hanger 3, and a front lower crossbeam 4. The main truss 1 adopts a double-triangular truss structure, and its transverse arrangement closely matches the position of the main longitudinal ribs of the π-shaped beam, forming a stable rigid support frame.

[0019] The design of the front upper crossbeam 2 breaks through the traditional long span constraint, significantly shortening its length. It only needs to be erected between two main trusses, so low-section steel beams can be used to replace the traditional truss form, greatly reducing the overall center of gravity of the hanging basket and improving its anti-overturning stability.

[0020] The suspension system has been optimized and simplified, and is now concentrated only in the area corresponding to the main longitudinal rib directly below the main truss. The intermediate redundant suspensions have been completely eliminated, forming a straight force transmission path of "main truss → suspension → main longitudinal rib", which completely solves the problem of force transmission ambiguity caused by load dispersion.

[0021] To address the deflection control requirements of ultra-wide spans, the lower front crossbeam 4 innovatively adopts a truss structure. When all components work together, the concrete load is transferred to the lower front crossbeam truss structure via the base basket, and then vertically transferred to the upper front crossbeam steel section through a simplified suspension system. Finally, the main truss guides the force flow into the already cast main beam, avoiding the low-stiffness area in the middle throughout the entire process.

[0022] This patent has the following advantages and beneficial effects:

[0023] This patent, through optimized structural design and structural system reconstruction, possesses the following advantages:

[0024] (1) Using steel profiles as the upper front crossbeam and a truss structure with a high center of gravity as the lower front crossbeam, the center of gravity of the hanging basket is lowered as a whole. This layout greatly enhances the structural stability of the hanging basket while meeting the same load-bearing requirements, and fundamentally solves the risks of high center of gravity and poor construction stability caused by high cross-section and truss upper crossbeam.

[0025] (2) The length of the front upper crossbeam is significantly shorter than that of the traditional rear support hanging basket, and it only needs to span two main trusses. This design breakthrough allows the upper crossbeam to directly use standardized steel components, which not only reduces the processing difficulty, but also directly reduces the amount of steel used and saves material costs;

[0026] (3) By simplifying and optimizing the position of the suspender system, the intermediate redundant suspenders are completely eliminated, and only the key force transmission suspenders in the corresponding area of ​​the main longitudinal rib are retained, so that the load is transmitted in a straight line along the path of "main truss → suspender → main longitudinal rib", thus completely eliminating the force transmission ambiguity problem caused by traditional multiple suspenders;

[0027] (4) The significant reduction in the number of hangers simultaneously reduces steel consumption and installation complexity, while the optimization of the force transmission path further reduces the local stress of the front upper crossbeam and extends the service life of the structure.

[0028] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system of upper and lower crossbeams in front of the hanging basket at the rear support of an ultra-wide variable-width π-shaped PC cable-stayed bridge, characterized in that... ； The aforementioned front upper and lower crossbeam system comprises a main truss (1), a front upper crossbeam (2), a hanger (3), and a front lower crossbeam (4); the main truss (1) adopts a double triangular truss structure, and its transverse arrangement closely matches the position of the main longitudinal rib of the π-shaped beam to form a stable rigid support frame. The front upper crossbeam (2) is erected between the two main trusses (1). It uses a low-section steel beam instead of the traditional truss form, which greatly reduces the overall center of gravity of the hanging basket and improves its anti-overturning stability. The hangers (3) are concentrated in the area corresponding to the main longitudinal rib directly below the main truss (1), and are connected to the front lower crossbeam (4) through the hangers (3). The front lower crossbeam (4) adopts a truss structure to meet the deflection control requirements of ultra-wide span.

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