A central buckle structure of a self-anchored suspension bridge

Abstract

This invention provides a self-anchored suspension bridge central buckle structure, characterized by multiple pairs of rigid central buckles installed in the mid-span. Each pair of rigid central buckles includes a central buckle clamp and a central buckle rod. The central buckle clamp is installed on the main cable, and the central buckle rod is formed by welding or bolting two I-beams in a herringbone pattern. The upper end of the central buckle rod connects to the central buckle clamp, and the lower end connects to the main beam. By adjusting the slope and cross-sectional dimensions of each central buckle, the stiffness of the multiple pairs of rigid central buckles is coordinated, forming multiple pairs of combined central buckles with different slopes and cross-sections. This allows the multiple pairs of central buckles to work together, evenly distributing the unbalanced force between the main cable and the main beam. This self-anchored suspension bridge central buckle structure effectively solves the problems of unfavorable bending at the base of the main tower and slippage of the main cable at the top of the tower in large-span self-anchored suspension bridges.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, in particular to a central buckle structure of a self-anchored suspension bridge. Background Art

[0002] A suspension bridge is a flexible structure. For a long-span suspension bridge with multiple towers and multiple spans, the structural system is more flexible. Under the action of live loads such as cars, especially under the most unfavorable live load conditions, that is, one span is fully loaded and the other span is unloaded, the structural deformation is large, and the main cable will generate a large unbalanced force at the top of the tower, and then generate a large bending moment at the bottom of the tower. In order to resist the bending moment at the bottom of the tower, the main tower section is usually adjusted to increase the bending bearing capacity of the main tower, but this method will aggravate the slip tendency of the main cable at the top of the tower. In response to the above problems, the common solution is to achieve the coordination of the structural system by adjusting the main tower section and the anti-slip measures of the main cable at the top of the tower. However, as the span of the suspension bridge increases, the main tower section will continue to increase, and the slip tendency of the main cable at the top of the tower will intensify. There will eventually be an incoordination between the two, which will restrict the development of the span of multi-tower suspension bridges.

[0003] In order to better solve the problem of bending of the main tower of a multi-tower and multi-span long-span suspension bridge, the patent of this invention proposes a central buckle structure of a self-anchored suspension bridge from another perspective, which connects the main cable and the main beam together in the middle of the span. Under the most unfavorable live load conditions, the central buckle structure can reduce the deformation of the main cable and the unbalanced force on the top of the main cable tower, thereby greatly reducing the bending moment at the bottom of the main tower.

[0004] Common central buckles are mainly divided into rigid central buckles and flexible central buckles. In use, flexible central buckles are usually set in multiple pairs, while rigid central buckles are often set in only one pair. The central buckles are subjected to less force, which is also the reason why the common central buckles are relatively small in size and relatively few in number. The central buckles are mainly used to improve the dynamic characteristics of the structure such as wind resistance and earthquake resistance, and are also used to reduce the longitudinal relative displacement of cables and beams, thereby improving the bending of short hangers in the span. However, there is no central buckle to solve the static problem of bending of the main tower under the most unfavorable live load conditions. Using the central buckle to solve the force problem of the main tower in the structural system, the central buckle will bear a large internal force. In order to reasonably design the central buckle structure, setting up multiple pairs of central buckles has become an inevitable choice. When the internal force is large, it will be very difficult to anchor the flexible central buckle. At this time, only multiple pairs of rigid central buckles can be set. The coordination of the stiffness of multiple pairs of rigid central buckles and the even distribution of the unbalanced force generated by the main cable at this point are the key to whether the central buckle setting is reasonable and the success or failure of the entire suspension bridge system.

[0005] The central buckle structure of a self-anchored suspension bridge of the present invention has a simple structure and greatly reduces the amount of material used compared to the amount of material used when the cross section of the main tower is increased; the method not only does not increase the unbalanced force of the main cable at the top of the tower, but reduces the unbalanced force; the method can achieve the stiffness coordination of multiple pairs of rigid central buckles and evenly distribute the unbalanced force of the main cable. The central buckle structure of a self-anchored suspension bridge of the present invention has high economy, rationality and effectiveness, and is of great significance to the design of the main tower of the suspension bridge and the development of the span. Summary of the invention

[0006] The purpose of the present invention is to provide a central buckle structure of a self-anchored suspension bridge, which can effectively solve the problems of bending of the main tower of a large-span suspension bridge and slippage of the main cable on the tower top. By adjusting the slope and cross-sectional size of the central buckle, the stiffness coordination of multiple pairs of rigid central buckles is achieved to form a combined central buckle, so that multiple pairs of central buckles can work together to evenly share the unbalanced force between the main cable and the main beam.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a central buckle structure of a self-anchored suspension bridge, characterized in that a plurality of pairs of rigid central buckles are arranged in the middle span, the plurality of pairs of rigid central buckles include a central buckle cable clamp and a central buckle rod body, the central buckle cable clamp is installed on the main cable, the central buckle rod body is formed by welding or bolting two I-shaped steel rods, the two I-shaped steel rods are distributed in a herringbone shape, the upper end of the central buckle rod body is connected to the central buckle cable clamp, and the lower end of the central buckle rod body is connected to the main beam, the plurality of pairs of rigid central buckles include an inner central buckle, and an outer central buckle located on both sides of the inner central buckle, the slope of the I-shaped steel rod of the inner central buckle is smaller than the slope of the I-shaped steel rod of the outer central buckle, the cross-sectional flange width of the I-shaped steel rod of the inner central buckle is larger than the cross-sectional flange width of the I-shaped steel rod of the outer central buckle, and the cross-sectional heights of the I-shaped steel rod of the inner central buckle and the I-shaped steel rod of the outer central buckle are the same.

[0008] Furthermore, the lower end of the central buckle cable clamp is welded to the central buckle rod body or connected with bolts.

[0009] Furthermore, for the steel main beam, the lower end of the central buckle rod body is welded to the main beam.

[0010] Furthermore, for the concrete main beam, the concrete main beam is provided with an embedded steel component, and then the lower end of the central buckle rod body is welded and connected to the embedded component.

[0011] The slope of the I-beam mentioned here refers to the ratio of the height of the I-beam to its projected length on the main beam.

[0012] The central buckle structure of a self-anchored suspension bridge of the present invention is used to solve the problems of bending of the main tower of a long-span suspension bridge and slippage of the main cable on the top of the tower. By setting a central buckle in the middle of the span as the anchor point of the main cable in the middle of the span, the rigidity of the structural system is increased, the unbalanced force between the main cable and the main beam is shared, and the bending moment at the bottom of the main tower is reduced; multiple pairs of rigid central buckles are used, and the distribution of the unbalanced force between the main cable and the main beam between the central buckles is achieved by adjusting their longitudinal slopes and cross-sectional dimensions, thereby reducing the unbalanced force on the top of the main cable tower under the most unfavorable live load conditions. The upper end of the rigid central buckle is connected to the main cable through a cable clamp to bear the unbalanced horizontal force of the main cable, and the lower end is connected to the main beam through welding or other structures suitable for the main beam structure. The middle is welded or bolted with an I-shaped steel rod to transfer the unbalanced force between the main cable and the main beam to the main beam for bearing. The present invention reduces its longitudinal stiffness by increasing the slope of the outer central buckle and reducing its cross-sectional size, and appropriately reduces the slope of the inner central buckle and appropriately increases its cross-sectional size, thereby ensuring that its longitudinal stiffness is coordinated with the longitudinal stiffness of the outer central buckle, so that the unbalanced force of the main cable can bear part of the horizontal force through the outer central buckle, and the remaining horizontal force can be distributed to the inner and rear central buckles, so that multiple pairs of central buckles evenly share the unbalanced force between the main cable and the main beam. The present invention achieves stiffness coordination of multiple pairs of central buckles by adjusting the longitudinal inclination slopes and cross-sectional sizes of multiple pairs of central buckles, ensuring that multiple pairs of rigid central buckles can jointly bear the unbalanced force between the main cable and the main beam, and has high economy, rationality and effectiveness, and is of great significance to the design of the main tower of the suspension bridge and the span development. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing the arrangement of multiple pairs of rigid central buckles of the present invention.

[0014] Figure 2 for Figure 1 The "I" shaped cross section of the center buckle shaft on the outside.

[0015] Figure 3 for Figure 1 The "I" shaped cross section of the center buckle shaft on the inner side.

[0016] Figure 4 for Figure 1 Cross-section of the mediolateral central cable clamp and the medial central cable clamp.

[0017] Figure 5 Layout diagram of multiple pairs of rigid central buckles in a self-anchored suspension bridge.

[0018] The figure includes: an outer central cable clamp 1, an inner central cable clamp 2, an outer central cable rod body 3, an inner central cable rod body 4, a main cable 5, and a main beam top surface 6. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and embodiments. In this embodiment, three pairs of central buckles are provided, which can be adjusted according to design requirements in actual applications.

[0020] Figure 1 The central buckle structure of a self-anchored suspension bridge of the present invention mainly comprises two pairs of outer central buckles and one pair of inner central buckles.

[0021] The outer central buckle is composed of an outer central buckle cable clamp 1 and an outer central buckle rod body 3. The outer central buckle cable clamp 1 is a conventional cable clamp for suspension bridges, and its cross section is as follows: Figure 4 The outer central buckle rod body 3 is a welded I-shaped cross section, which is welded by two I-shaped steel rods distributed in a herringbone shape. Its cross section is as shown in FIG. Figure 2 As shown. The outer central buckle cable clamp 1 is installed on the main cable, and the lower end is welded to the outer central buckle rod body 3 or connected with bolts. The upper end of the outer central buckle rod body 3 is connected to the outer central buckle cable clamp 1, and the lower end is connected to the main beam. For steel main beams, the lower end of the outer central buckle rod body 3 is welded to the main beam. For concrete main beams, embedded steel components can be used and then welded to the embedded parts. The longitudinal slope of the outer central buckle rod body k1=a1 / 1b1, k3=a3 / b3, a1, a3 are the heights of the central buckle, and the values ​​of a1, a3 are determined according to the design. In order to ensure the reasonable force of the central buckle, the values ​​of a1, a3 should not be too large during design. b1, b3 are the projected lengths of the outer central buckle rod body 3 on the main beam. Figure 2 It is the cross section of the outer central buckle rod body 3, which is a welded I-section. The transverse dimension c is the height of the I-section, and the longitudinal dimension d1 is the flange width of the I-section.

[0022] The inner central buckle is composed of an inner central buckle cable clamp 2 and an inner central buckle rod body 4. The inner central buckle cable clamp 2 is a conventional cable clamp for a suspension bridge, and its cross section is as follows: Figure 4 The inner central buckle rod body 4 is a welded I-shaped cross section, and its cross section is as shown in FIG. Figure 3 As shown. The inner central buckle cable clamp 2 is installed on the main cable, and the lower end is welded to the inner central buckle rod body 4 or connected with bolts. The upper end of the inner central buckle rod body 4 is connected to the inner central buckle cable clamp 2, and the lower end is connected to the main beam. For steel main beams, the lower end of the inner central buckle rod body 4 is welded to the main beam. For concrete main beams, embedded steel components can be used and then welded to the embedded parts. The longitudinal slope of the inner central buckle k2=a2 / b2, a2 ​​is the height of the central buckle, and the value of a2 is determined according to the design. In order to ensure the reasonable force of the central buckle, the value of a2 should not be too large during design. b2 is the projection length of the inner central buckle rod body 4 on the main beam. Figure 3It is the cross section of the inner center buckle rod body 4, which is a welded I-section. The transverse dimension c is the height of the I-section, and the longitudinal dimension d2 is the width of the I-section flange.

[0023] In order to achieve the average distribution of the horizontal unbalanced force of the main cable by multiple pairs of central buckles, it is necessary to continuously adjust the slopes k1 and k3 of the outer central buckles and the slope k2 of the inner central buckle. Generally, k1 and k3 are ≥ k2, and the sizes of k1 and k3 are generally close. The specific values ​​are determined according to the calculation needs. Preferably, the ratio of k1, k3 and k2 is preferably 1.5~2:1. The size of the outer central buckle shaft 3 and the size of the inner central buckle shaft 4 have the same value c in the cross-sectional height. The respective flange sizes have a greater influence on the longitudinal stiffness. To adjust their stiffness, it can also be achieved by changing the values ​​of the cross-sectional flange widths d1 and d2. Generally, d1≤d2. Simultaneously adjusting the values ​​of k1, k2, k3, d1, and d2 can more quickly achieve the coordination of the longitudinal stiffness of multiple pairs of rigid central buckles, so that the longitudinal stiffness of the outer central buckle is smaller than that of the inner central buckle.

[0024] The present invention provides a central buckle structure for a self-anchored suspension bridge. By arranging a plurality of pairs of rigid central buckles with different longitudinal slopes, the stiffness coordination of the central buckles is achieved, and combined central buckles with different slopes and different cross-sections are formed. The structure can significantly reduce the bending moment at the bottom of the main tower of the suspension bridge, significantly improve the anti-slippage of the main cable at the top of the tower, and solve important problems in the design of multi-tower, multi-span and large-span suspension bridges, which is of great significance.

[0025] Although the above-mentioned illustrations and descriptions provide a detailed example of the central buckle structure of a self-anchored suspension bridge of the present invention, it is not intended to limit the present invention to the specific structure and applicable scope shown and described. Therefore, all corresponding modifications and equivalents that may be used are within the scope of the patent applied for by the present invention.

Claims

1. A central buckle structure of a self-anchored suspension bridge, characterized in that A plurality of pairs of rigid central buckles are arranged in the middle span, the plurality of pairs of rigid central buckles include a central buckle cable clamp and a central buckle rod body, the central buckle cable clamp is installed on the main cable, the central buckle rod body is formed by welding or bolting two I-shaped steel rods, the two I-shaped steel rods are distributed in a herringbone shape, the upper end of the central buckle rod body is connected to the central buckle cable clamp, and the lower end of the central buckle rod body is connected to the main beam, the plurality of pairs of rigid central buckles include an inner central buckle and an outer central buckle located on both sides of the inner central buckle, the slope of the I-shaped steel rod of the inner central buckle is smaller than that of the outer central buckle The slope of the I-shaped steel bar with the buckle, the flange width of the cross-section of the I-shaped steel bar with the inner central buckle is greater than the flange width of the cross-section of the I-shaped steel bar with the outer central buckle, and the cross-sections of the I-shaped steel bar with the inner central buckle and the I-shaped steel bar with the outer central buckle have the same height; the lower end of the central buckle cable clamp is welded to the central buckle rod body or connected with bolts; for the steel main beam, the lower end of the central buckle rod body is welded to the main beam; for the concrete main beam, the concrete main beam is provided with embedded steel components, and then the lower end of the central buckle rod body is welded to the embedded parts.

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