Main cable system suitable for small and medium span suspension bridge, suspension bridge and method

Abstract

The invention discloses a main cable system suitable for a medium-and-small-span suspension bridge, the suspension bridge and a method, and solves the problems that in the prior art, a catwalk needs to be erected on a medium-and-small-span suspension bridge structure, the process cost is high, an anchorage is large, and the dehumidification difficulty is large. The main cable system has the beneficial effects that construction is convenient, quality and durability are better guaranteed, and the size of an anchorage is reduced, and the specific scheme is as follows: the main cable system suitable for the small and medium span suspension bridge comprises a main cable, the main cable is a factory prefabricated part and comprises a cable body, the cable body comprises a plurality of steel strands or a plurality of steel wires, and the steel strands or the steel wires in the cable body are coated with anticorrosive coatings in the circumferential direction; the cable body is wrapped with a protective structure layer, the length of the cable body exceeds the protective structure layer, the steel strands or the steel wires, exceeding the protective structure layer, of the cable body are dispersed into a plurality of cable strands, and the end of the dispersed part of the steel strands or the steel wires is provided with an anchor head used for anchoring with an anchor body.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of main cable of suspension bridge, and particularly relates to a main cable system suitable for small and medium span suspension bridge, a suspension bridge and a method. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] The suspension bridge is favored due to its unique landscape effect, but the high cost and the later maintenance cost are the primary factors restricting the application of the small and medium span suspension bridge, and the reason is that the erection cost of the main cable is too high, the forming process of the main cable is too much, and the later maintenance cost is high.

[0004] In the construction of the main cable, the more mature main cable erection scheme at home and abroad, whether it is the PPWS (precast parallel wire strand) method or the AS spinning method (air spinning method), needs to erect a catwalk to provide a construction platform for the traction and forming of the main cable. For the small and medium span suspension bridge (the suspension bridge with a span of less than 500 m), the use of the process method will obviously lead to high cost, thereby restricting the selection of the bridge type.

[0005] In the durability of the main cable, the main cable as the main load-bearing component of the suspension bridge is almost not replaceable in the later period, and the durability of the main cable is directly related to the service life of the bridge. The composition material of the conventional main cable of the suspension bridge is galvanized or galvanized-aluminum alloy high-strength steel wire. When the main cable steel wire is in a humid and easily-corrosive environment for a long time, with the increase of the service life of the suspension bridge, the main cable may be corroded and broken, thereby affecting the carrying capacity of the main cable. In recent years, the main cable opening detection of the suspension bridge found that the main cable steel wire of some suspension bridges was corroded to different degrees, thereby affecting the operation safety of the suspension bridge. For the small and medium span suspension bridge, if the surface sealing wrapping protection of the on-site construction and the main cable dehumidification system are used, the construction difficulty and the construction period will be increased, and the operation cost in the later period will also be increased.

[0006] In the anchoring of the main cable, the commonly used anchoring system of the main cable includes a steel system and a prestressed system, and the volume of the anchoring system is large, the construction is complicated, and the structure is complex. For the small and medium span suspension bridge, the cable force is usually small, and the use of the above system will lead to the increase of the scale of the anchorage, thereby increasing the engineering cost and the construction period.

[0007] In summary, the small and medium span suspension bridge has the problems of high process cost, large anchorage and large dehumidification difficulty due to the small cable force and the small cross-sectional area of the main cable. SUMMARY

[0008] In view of the problems in the prior art, the present application aims to provide a main cable system suitable for small and medium span suspension bridge, which is rapid and convenient in construction, low in operation cost, and good in corrosion resistance.

[0009] To achieve the above object, the present application is realized by the following technical solutions: A main cable system suitable for small and medium span suspension bridges, comprising a main cable, the main cable being a factory prefabricated part, the main cable comprising a cable body, the cable body comprising a plurality of steel strands or a plurality of steel wires, the steel strands or the steel wires in the cable body being coated with anticorrosive layer in a ring shape, the cable body being wrapped with a protective structure layer, the length of the cable body exceeding the protective structure layer, the steel strands or the steel wires of the cable body exceeding the protective structure layer being dispersed into a plurality of strands, the ends of the steel strand or steel wire strands being provided with anchor heads for anchoring with anchor bodies.

[0010] The main cable system suitable for small and medium span suspension bridges as described above, when the cable body comprises a plurality of steel strands, the inner side of the protective structure layer is arc-shaped to ensure that the steel strands are closely attached to the inner side of the protective structure layer and that the cable body is closely contacted with the protective structure layer.

[0011] The main cable system suitable for small and medium span suspension bridges as described above, when the cable body comprises a plurality of steel wires, the inner side of the protective structure layer is polygonal to ensure that the steel wires are closely attached to the inner side of the protective structure layer and that the cable body is closely contacted with the protective structure layer.

[0012] The main cable system suitable for small and medium span suspension bridges as described above, the ends of the protective structure layer can be provided with a strand dispersing sleeve, the strand dispersing sleeve comprising two halves, the two halves of the strand dispersing sleeve being wrapped around the part of the cable body exceeding the protective structure layer, the strand dispersing sleeve being trumpet-shaped. The length of the strand dispersing sleeve is determined according to the diameter of the main cable, and the length of the strand dispersing sleeve is 0.5m-2m.

[0013] The main cable system suitable for small and medium span suspension bridges as described above, the protective structure layer is made of plastic material, and the protective structure layer is fixed to the ring of the cable body by thermoplastic method.

[0014] The main cable system suitable for small and medium span suspension bridges as described above, the anchor heads provided at the ends of the adjacent two steel strands or steel wires are arranged in a staggered manner, and the anchor heads can cooperate with the cable anchor.

[0015] The main cable system suitable for small and medium span suspension bridges as described above, when the steel strands or the steel wires exposed to the protective structure layer are dispersed into an odd number of strands, one of the strands is arranged at the center anchoring point of the anchor body, and the other strands are symmetrically arranged about the center anchoring point.

[0016] The main cable system suitable for small and medium span suspension bridges as described above, when the steel strands or the steel wires exposed to the protective structure layer are dispersed into an even number of strands, all the strands are symmetrically arranged about the center anchoring point.

[0017] In a second aspect, the present application further provides a small and medium span suspension bridge adopting the main cable system.

[0018] In a third aspect, the present application further provides a construction method of the main cable system for the small and medium span suspension bridge, comprising the following contents: The steel strands or steel wires are processed in a factory, and the anticorrosive layer is coated in the circumferential direction of the steel strands or steel wires; The cable body is made of a plurality of steel strands or a plurality of steel wires; The protective structure layer is wrapped outside the cable body, the length of the cable body exceeds the protective structure layer, the end of the steel strand or steel wire strand is provided with an anchor head for anchoring with the anchor body, and the factory prefabrication of the main cable is completed; The prefabricated main cable is transported to the construction site, transported to the bridge site, the end of the protective structure layer is provided with a cable dispersion sleeve, the strand in the cable body exceeds the cable dispersion sleeve, the anchor head at the end of the strand is anchored to the anchor body after the main cable is pulled by the traction device.

[0019] The beneficial effects of the present application are as follows: 1) The main cable system provided by the present application has a reasonable structure, the main cable is a factory prefabricated part, that is, the cable body is manufactured in the factory, and the anticorrosive layer is coated outside the cable body. After the anticorrosive layer is coated, the main cable is formed by wrapping the protective structure layer, the on-site cable winding process is cancelled, and the catwalk construction platform is cancelled, so that the on-site construction of the main cable is not required. The prefabricated main cable can realize rapid installation of the main cable, and facilitate rapid construction.

[0020] 2) In the present application, the protective structure layer is wrapped in the circumferential direction of the cable body, the protective structure layer serves as permanent protection, has the functions of sealing and protecting the cable body, cancels the on-site wire winding protection and dehumidification device, and optimizes the anticorrosion mode. The prefabricated main cable has the characteristics of excellent anticorrosion performance, and the quality and durability are more guaranteed.

[0021] 3) The main cable of the present application optimizes the anchor head structure, cancels the complex anchoring system, and provides the anchor head at the end of the steel strand or steel wire strand for anchoring with the anchor body. The anchor head is convenient to cooperate with the smaller volume stay cable anchor and facilitates construction. A large-scale anchor is not required, the maintenance workload is reduced, and the engineering cost is reduced.

[0022] 4) In the present application, the anchoring positions of the strands at the anchor body are reasonably arranged according to the odd and even number of the strands, so as to ensure the anchoring effect and quality of the main cable, and facilitate construction.

[0023] 5) The construction method provided by the present application utilizes the factory prefabricated main cable as the main cable structure, so as to facilitate the construction speed of the main cable, so that only the traction device is used to pull the main cable, and the construction of the main cable can be rapidly realized on site. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, and are incorporated into and constitute a part of this specification. The embodiments of the application, and their

[0025] Figure 1 is a schematic view of a main cable system for a small and medium span suspension bridge according to one or more embodiments of the present application.

[0026] Figure 2 is a schematic view of the end of a main cable system for a small and medium span suspension bridge according to one or more embodiments of the present application.

[0027] Figure 3 is a schematic view of a longitudinal section of a main cable system for a small and medium span suspension bridge according to one or more embodiments of the present application, in which the cable body is a steel strand.

[0028] Figure 4 is a schematic view of a longitudinal section of a main cable system for a small and medium span suspension bridge according to one or more embodiments of the present application, in which the cable body is a steel wire.

[0029] Figure 5 is a schematic view of the anchoring point arrangement of a main cable system for a small and medium span suspension bridge according to one or more embodiments of the present application.

[0030] In the drawings: the mutual spacing or dimensions are exaggerated for showing the positions of the parts, and the schematic views are merely schematic.

[0031] In the drawings: 1. main cable, 2. cable dispersion sleeve, 3. anchor head, 4. anchor head front anchoring surface, 5. steel strand, 6. steel wire, 7. protective structural layer. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed description is merely exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0033] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the terms "comprises", "comprising", "includes", "including", "contains", "containing" or variations thereof do not specify an exhaustive inclusion or list, and that the terms are not intended to exclude other possible components or methods; As introduced in the background, the small and medium span suspension bridge structure in the prior art needs to set up catwalk, and has problems of high process cost, large anchorage, and large difficulty in dehumidification. In order to solve the above technical problems, the present application provides a main cable system suitable for small and medium span suspension bridge.

[0034] Embodiment one In a typical embodiment of the present application, referring to Figure 1 Fig. 1, a main cable system suitable for small and medium span suspension bridge includes a main cable 1, which is a factory prefabricated part. The main cable 1 includes a cable body, which includes a plurality of steel strands 5 or a plurality of steel wires 6. The steel strands 5 or steel wires in the cable body are coated with anticorrosive layer in a ring shape. The cable body is wrapped with a protective structure layer 7. The length of the cable body exceeds the protective structure layer 7. The steel strands 5 or steel wires of the cable body exceeding the protective structure layer 7 are dispersed into a plurality of cable strands (one steel strand is one cable strand, and a plurality of steel wires form one cable strand). The end of the cable strand is provided with an anchor head 3 for anchoring with an anchor body. The main cable 1 is completed with manufacturing and processing and construction of the protective structure layer in the factory. Compared with the conventional main cable of suspension bridge, the main cable 1 is once pulled into place in the construction process, and there is no operation step of preparing steel wire bundle, so that the catwalk does not need to be erected. The linear control accuracy of the main cable 1 is also higher. Moreover, the construction process and period are greatly optimized, the durability of the main cable 1 is improved, the temporary works are reduced, and the cost and construction difficulty are reduced.

[0035] In the embodiment, the protective structure layer 7 is made of plastic material such as high-density polyethylene (HDPE). The protective structure layer 7 has a set thickness. The thickness of the protective structure layer 7 is within 5-15 mm, so as to ensure the strength of the protective structure layer 7. The protective structure layer 7 is fixed to the ring of the cable body by hot plastic method. The integrated protective structure layer 7 cancels the on-site winding wire protection process and the main cable dehumidification device, so as to ensure the sealing performance. In some examples, the protective structure layer 7 can be provided with multiple layers, so as to ensure the service life of the protective structure layer 7.

[0036] Referring to Figure 2 Fig. 2, the main cable 1 is dispersed into a plurality of cable strands in the anchor chamber, so as to facilitate dispersed anchoring. The main cable 1 is converted into dispersed anchoring by setting the anchor head at the end of the cable strand, so as to reduce the stress level at the anchoring position and ensure the safety of the anchoring structure. The anchor heads 3 at the ends of the adjacent two steel strands or steel wires are set in staggered manner. The anchor head 3 can cooperate with the cable-stayed cable anchor, and the connection is reliable. The anchor head 3 is the existing anchoring head cooperating with the cable-stayed cable anchor. In this way, a large anchor is not needed, and the space of the anchoring system and the volume of the anchor are reduced. The cable-stayed cable anchor is fixed in the anchor chamber. The anchor head 3 is set with a spacing distance between the anchor head 3 and the front anchor surface 4 of the anchor. The number of the anchor head 3 can be adjusted in combination with the size of the front anchor surface 4 of the anchor (that is, the anchor body) and the internal force of the main cable 1, and the anchor head 3 is symmetrically arranged.

[0037] In some examples, a dehumidification mechanism such as a dehumidifier is arranged in the anchor chamber of the anchorage, which is conducive to removing the moisture in the anchor chamber.

[0038] Referring to Figure 3 As shown, when the cable body includes a plurality of steel strands 5, the inner side of the protective structural layer 7 is arc-shaped, and the protective structural layer 7 is effectively attached to the steel strands 5 in the cable body during the forming process, so as to avoid the moisture in the external air from entering the internal part of the main cable 1. Referring to Figure 4 As shown, when the cable body includes a plurality of steel wires 6, the inner side of the protective structural layer 7 is polygonal to ensure that the steel wires 6 are closely attached to the inner side of the protective structural layer, and the polygonal shape can be regular or irregular. The steel wires 6 fill the internal part of the protective structural layer 7, so as to ensure the close contact between the cable body and the protective structural layer 7 and effectively avoid the moisture in the external air from entering the internal part of the main cable.

[0039] Referring to Figure 5 As shown, a coordinate system is established with the width direction of the suspension bridge as the Y axis and the height direction as the Z axis. When the steel strands 5 or steel wires 6 exposed to the protective structural layer 7 are dispersed into an odd number of cable strands, one of the cable strands is arranged at the center anchoring point of the anchorage (the center anchoring point is arranged along the center line of the main cable), and the other cable strands are symmetrically arranged about the center anchoring point. For example, when there is only one cable strand, the anchoring point of the cable strand is the center anchoring point of the anchorage; when there are three cable strands, the other two anchoring points are arranged on the two sides of the center anchoring point; when there are five cable strands, four anchoring points are arranged in four quadrants; when there are seven cable strands, four anchoring points are arranged in four quadrants, and the other two anchoring points are arranged along the Z direction; and when there are nine cable strands, four anchoring points are arranged in four quadrants, two anchoring points are arranged along the Z direction, and two anchoring points are arranged along the Y direction.

[0040] When the steel strands 5 or steel wires 6 arranged in the cable body are dispersed into an even number of cable strands, all the cable strands are symmetrically arranged about the center anchoring point. When there are two cable strands, the two anchoring points are arranged along the Z direction; when there are four cable strands, the four anchoring points are arranged in four quadrants; when there are six cable strands, the four anchoring points are arranged in four quadrants, and the other two anchoring points are arranged along the Z direction; when there are eight cable strands, the four anchoring points are arranged in four quadrants; two anchoring points are arranged along the Y direction, and two anchoring points are arranged along the Z direction (i.e., the height direction); and when there are ten cable strands, the four anchoring points are arranged in four quadrants, two anchoring points are arranged along the Y direction, and four anchoring points are arranged along the Z direction (i.e., the height direction).

[0041] In addition, the end of the protective structure layer 7 can be provided with a fairlead 2, the fairlead 2 including two half-symmetrical structures which are locked by bolts and nuts, the two half fairleads being arranged around the cable body beyond the protective structure layer, the fairlead 2 being trumpet-shaped, the fairlead 2 guiding the steel strands 5 or steel wires 6 beyond the protective structure layer to avoid the steel strands 5 or steel wires 6 being too scattered, the length of the fairlead 2 being determined according to the diameter of the main cable 1, the length of the fairlead 2 being 0.5m-2m.

[0042] The main cable provided by the embodiment adopts a whole-bundle finished product structure, the cable body processing and cable body protection are completed in a factory, the quality and durability are more guaranteed, the main cable 1 is dispersed into a plurality of cable strands at an anchoring position, the anchor head is processed in the factory, after the whole-bundle main cable 1 is processed in the factory, the main cable 1 is transported to a bridge position, is anchored after being erected by a pilot cable, and the main cable does not need to be erected by a catwalk, so that the construction is fast and convenient, a main cable dehumidifying device is not needed in the operation period, the operation period cost is low, the corrosion resistance is good, the conventional main cable system cannot solve the above problems, and the main cable general system for the medium and small span suspension bridges is realized.

[0043] Embodiment two The embodiment provides a medium and small span suspension bridge, and a main cable system suitable for the medium and small span suspension bridge is used, the medium and small span suspension bridge being less than or equal to 500m in span.

[0044] The main cable system is safe and reliable, simple in structure, good in protection performance, and good in durability, the anchoring of the main cable and the anchor is safe and reliable, force transmission is smooth, the main cable can be conveniently erected, fast construction can be realized, the operation period maintenance cost is reduced, temporary measures are reduced, and the cost is reduced, the durability of the main cable of the medium and small span suspension bridge is guaranteed, the rationality of the anchoring structure of the main cable and the anchor is guaranteed, the problem of high construction cost of the main cable of the medium and small span suspension bridge is solved, and the construction is convenient and feasible.

[0045] Embodiment three A construction method of a main cable system suitable for a medium and small span suspension bridge, including the following contents: The steel strands 5 or steel wires 6 are processed in a factory, and a corrosion-resistant layer is brushed in the circumferential direction of the steel strands 5 or steel wires 6; The cable body is made of a plurality of steel strands 5 or a plurality of steel wires 6; The protective structure layer 7 is arranged outside the cable body, the length of the cable body is arranged beyond the protective structure layer 7, the end of the cable strand composed of the steel strands 5 or steel wires is provided with the anchor head 3 for anchoring with the anchor body, and the factory prefabrication of the main cable 1 is completed; The prefabricated main cable 1 is transported to the construction site, transported to the bridge site, the cable head 2 is arranged at the end of the protective structure layer 7, the cable strand in the cable body is arranged beyond the cable head 2, the anchor head 3 at the end of the cable strand is anchored to the anchor body after the main cable 1 is pulled once through the traction device (the pilot cable is used as the traction device for the main cable to cross the river).

[0046] The construction method of the main cable system provided in the embodiment is that the main cable is prefabricated and produced in a factory, then the main cable is transported to the site, the end of the main cable is anchored after being pulled by the pilot cable, and the main cable does not need to be constructed by erecting a catwalk, so that the construction is rapid and convenient.

[0047] The above merely describes the preferred embodiments of the present application, but is not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A main cable system suitable for small and medium span suspension bridges, characterized in that: It includes a main cable, which is a prefabricated part in the factory. The main cable includes a cable body, which includes several steel strands or several steel wires. The steel strands or steel wires in the cable body are circumferentially coated with an anti-corrosion layer. The cable body is wrapped with a protective structural layer. The length of the cable body exceeds the protective structural layer. The steel strands or steel wires of the cable body exceeding the protective structural layer are dispersed into several cable strands. The ends of the steel strands or steel wire strands are provided with anchor heads for anchoring with the anchor body.

2. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: When the cable body includes a plurality of steel strands, the inner side of the protective structure layer is an arc-shaped surface.

3. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: When the cable body includes a plurality of steel wires, the inner side of the protective structure layer is polygonal to ensure that the steel wires are closely fitted to the inner side of the protective structure layer.

4. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: A loose cable sleeve may be provided at the end of the protective structure layer. The loose cable sleeve comprises two halves. The two halves of the loose cable sleeve are provided around the portion of the cable body that extends beyond the protective structure layer. The loose cable sleeve is in a trumpet shape. The length of the loose cable sleeve is determined according to the diameter of the main cable, and the length of the loose cable sleeve is 0.5m-2m.

5. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: The protective structure layer is made of plastic material and is fixed to the circumferential direction of the cable body by thermoplastic means.

6. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: The anchor heads arranged at the ends of two adjacent steel strands or steel wires are staggered, and the anchor heads can cooperate with the inclined cable anchors.

7. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: When the steel strands or steel wires exposed outside the protective structure layer are dispersed into an odd number of strands, one of the strands is placed at the central anchoring point of the anchor body, and the other strands are arranged symmetrically about the central anchoring point.

8. The main cable system suitable for small and medium span suspension bridges according to claim 1, characterized in that: When the steel strands or steel wires exposed outside the protective structure layer are dispersed into an even number of strands, all the strands are arranged symmetrically about a central anchoring point.

9. A small to medium span suspension bridge, characterized in that: A main cable system suitable for small and medium span suspension bridges according to any one of claims 1 to 8 is adopted.

10. The construction method of a main cable system for a small to medium span suspension bridge according to claim 4, characterized in that: Includes the following: Process the steel strands or steel wires in the factory and apply an anti-corrosion coating on the circumferential direction of the steel strands or steel wires; The cable body is made of a plurality of steel strands or a plurality of steel wires; A protective structure layer is provided on the outside of the cable body, the length of the cable body exceeds the protective structure layer, and an anchor head is provided at the end of the steel strand or steel wire rope strand for anchoring with the anchor body, thus completing the factory prefabrication of the main cable; The prefabricated main cable is transported to the construction site and then to the bridge location. A loose cable sleeve is set at the end of the protective structure layer. The cable strands in the cable body extend beyond the loose cable sleeve. A guide cable is set at the end of the main cable. After the guide cable is pulled by a traction device, the anchor head at the end of the cable strand is anchored to the anchor body.

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