Vertical rotation construction method for arch rib of arch bridge

Abstract

According to the vertical rotation construction method of the arch bridge arch rib, in the vertical rotation stage, the new bridge bearing platform is used as a buckle cable ground anchor for vertical rotation of the arch rib, a temporary ground anchor is omitted, and the problem that under the condition of limitation of channels and sites, ground anchor arrangement in the vertical rotation stage is limited by the sites is solved.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and in particular to a method for vertical rotation construction of the arch rib of an arch bridge. Background Technology

[0002] In modern bridge engineering, steel pipe basket arch bridges have become an important choice for constructing bridges in complex terrain and for long spans due to their superior spanning capacity and unique aesthetic value. As the core load-bearing component, the safety, efficiency, and precision of the main arch's installation and construction directly determine the quality of the project; therefore, the research and optimization of related technologies remain a key issue in the industry.

[0003] In existing technologies, the main arch construction methods for steel pipe basket arch bridges in water-related environments typically include cable-stayed crane + cable-stayed suspension method, full-span scaffolding method, off-site assembly followed by overall floating installation method, and vertical rotation method. The cable-stayed crane + cable-stayed suspension method relies on heavy-duty equipment and tall towers, which is not only costly but also has stringent terrain requirements, limiting its application scenarios. The full-span scaffolding method consumes a large amount of materials, occupies space under the bridge for a long period, and obstructs traffic when crossing waterways, thus extending the construction period and causing economic losses. The off-site assembly followed by overall floating installation method is significantly affected by wind and waves, and large-span arch ribs require two vessels working together, further increasing the risk. In contrast, the traditional vertical rotation construction method, which involves setting up anchor towers and hinges on both banks, assembling two semi-arches on a low-level assembly scaffold, and then completing the installation through vertical rotation and closure, has advantages such as low cost, high efficiency, low risk, and low material consumption. Meanwhile, compared to the cable-stayed construction system commonly used in traditional arch bridge construction, the vertical rotation method only requires the erection of low towers and construction anchors, which is less constrained by the site and has relatively relaxed requirements for terrain. However, in urban environments with extremely limited terrain, the cable anchors relied upon during the vertical rotation stage usually still require separate temporary foundations, which not only occupy more space but also face greater construction difficulties and poor stability in soft soil foundations or areas with limited space, directly threatening construction safety and leading to a significant increase in risks and costs. In addition, existing conventional vertical rotation methods have significant limitations in water-related environments: the low-level assembly stage is constrained by waterways and water systems, land transportation cannot directly reach the bridge site, and water transportation places high demands on hoisting equipment and is very costly, thus limiting the application of vertical rotation construction.

[0004] In summary, existing arch rib installation technologies all have significant bottlenecks in water-related environments where construction sites are limited, and innovative methods are urgently needed to achieve safe, efficient, and low-cost installation of arch ribs for steel pipe basket arch bridges. Summary of the Invention

[0005] The present invention aims to at least solve the technical problems mentioned in the background art above, and provide a method for vertical rotation construction of arch ribs of arch bridges, which solves the technical problem of the ground anchor setting being limited by the site under the constraints of waterway and site.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for vertically rotating an arch rib of an arch bridge, wherein the arch rib comprises two semi-arch structures, each semi-arch structure being assembled sequentially from several arch rib segments. One end of each semi-arch structure is connected to a hinge on a corresponding arch seat, and the other end of each semi-arch structure is provided with a closure joint for connection to the other semi-arch structure. The method for vertically rotating the arch rib of the arch bridge includes the following steps: S1, Construction preparation: First anchors are pre-embedded on the piers on both sides of the arch bridge to form cable anchors. Low-position assembly supports and rotating towers are erected. Two sets of low-position assembly supports are set up corresponding to the support positions of the two semi-arch structures. Two rotating towers are set up corresponding to the two semi-arch structures. The two rotating towers are respectively set between the first anchors and the low-position assembly supports on both sides of the arch bridge. S2, Low-position assembled arch rib: The prefabricated arch rib segments are transported to the corresponding low-position assembly brackets for assembly to form two semi-arch structures, and the lower ends of the two semi-arch structures are connected to the hinges on the corresponding arch seats. S3, Arch Rib Rotation Construction: One end of the sling is connected to the corresponding first anchor through a hydraulic lifting device. The other end of the sling is threaded through the cable saddle pulley at the top of the corresponding rotating tower and then connected to the free end of the corresponding semi-arch structure. The sling is driven by the hydraulic lifting device to perform vertical rotation of the corresponding semi-arch structure until the design position is reached. Then the closure joint of the two semi-arch structures is connected together to achieve closure.

[0007] Furthermore, in step S1, second anchors are pre-embedded on the piers on both sides of the arch bridge to form guy ropes. The second anchors are located on the side of the corresponding rotating tower facing away from the low-position assembly support. When the rotating tower is erected, longitudinal guy ropes are pulled on the two rotating towers. The longitudinal guy ropes include two rear guy ropes and one front guy rope. One end of each of the two rear guy ropes is connected to the two second anchors, and the other end of each rear guy rope is connected to the top of the two rotating towers. The two ends of the front guy rope are connected to the top of the two rotating towers.

[0008] Furthermore, the bearing platform with the first anchor and the bearing platform with the second anchor are connected to adjacent bearing platforms by reinforcing beams.

[0009] Furthermore, the closure joint provided on one half of the arch structure is the first closure joint, and the closure joint provided on the other half of the arch structure is the second closure joint. Both the first closure joint and the second closure joint include a first extension arm and a second extension arm extending from the free end of the corresponding half of the arch structure toward the other half of the arch structure. The first extension arm is located above the second extension arm. The extension length of the first extension arm of the first closure joint is greater than that of the second extension arm, and the extension length of the first extension arm of the second closure joint is less than that of the second extension arm. The first extension arm of the first closure joint is connected to the first extension arm of the second closure joint, and the second extension arm of the first closure joint is connected to the second extension arm of the second closure joint.

[0010] Furthermore, in step S3, driving the buckle to vertically rotate the corresponding semi-arch structure via the hydraulic lifting device includes the following steps: Install the fastening cable corresponding to the semi-arch structure equipped with the first closure joint; The semi-arch structure with the first closure joint is rotated vertically. After the rotation is in place, the part of the low-level assembly bracket corresponding to the semi-arch structure with the first closure joint that obstructs the vertical rotation of the other semi-arch structure is removed. Install the fastening cable corresponding to the semi-arch structure equipped with the second closure joint; The semi-arch structure equipped with the second closure joint is vertically rotated. After the rotation is in place, the first extension arm of the first closure joint is connected to the first extension arm of the second closure joint, and the second extension arm of the first closure joint is connected to the second extension arm of the second closure joint. Then, the arch top web member is installed between the first extension arm of the first closure joint and the first extension arm of the second closure joint to complete the vertical rotation installation of the arch rib.

[0011] Furthermore, the arch bridge is constructed at the site of the old bridge. In step S2, the old bridge is used as a transportation channel during the process of transporting the prefabricated arch rib segments to the corresponding low-level assembly supports. The prefabricated arch rib segments are transferred to one end of the old bridge by land or water transportation. Using the transportation equipment set on the old bridge, the arch rib segments are transported longitudinally along the old bridge to the low-level assembly position of the new bridge arch rib. Then, using the hoisting equipment, the arch rib segments transported to the low-level assembly position are hoisted sequentially onto the corresponding low-level assembly supports for assembly according to the design sequence.

[0012] Furthermore, the top of the low-position assembly bracket is provided with an arch rib support member. The arch rib support member includes a support frame fixed to the top of the low-position assembly bracket and a positioning groove fixed to the support frame for placing the arch rib segment. The positioning groove can position the arch rib segment in a preset inclined posture.

[0013] Furthermore, the positioning groove is formed by a base plate and a backing plate, both of which are fixedly connected to the support frame. The base plate is inclined relative to the horizontal plane, and the backing plate is vertically connected to the base plate.

[0014] Furthermore, the bottom end of the rotating tower is fixed to the pier platform of the transition pier on both sides of the river channel of the arch bridge, and the arch seat is provided on the pier platform of the transition pier.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects: The present invention provides a method for vertical rotation construction of arch bridge ribs. In the vertical rotation stage, it overcomes the limitations of the construction site by using the new bridge abutment as the anchor for the vertical rotation of the arch ribs, eliminating the need for temporary anchors and solving the problem of limited anchor placement during the vertical rotation stage due to waterway and site constraints.

[0016] The vertical rotation construction method for the arch rib of the arch bridge of the present invention optimizes the closure joint of the semi-arch structure closure joint. The first extension arm and the second extension arm of the closure joint of the two semi-arch structures are of different lengths, which significantly enhances the controllability of the vertical rotation process.

[0017] The vertical rotation construction method for arch ribs of arch bridges in this invention innovatively transforms existing old bridges into longitudinal transportation channels for new bridge arch rib segments during the low-position assembly stage. This reduces the cost of constructing temporary transportation channels and minimizes the risks associated with complex transportation and equipment operation in confined spaces. Furthermore, the low-position assembly support system precisely matches the structural inclination characteristics of the basket arch bridge using customized arch rib support components, ensuring the stability and positioning accuracy of the arch rib segments during assembly. Attached Figure Description

[0018] Figures 1-3 This is a schematic diagram of the construction process of a preferred embodiment of the vertical rotation construction method for the arch rib of an arch bridge according to the present invention.

[0019] Figure 4 for Figure 1 Enlarged view of the structure at point A.

[0020] Figure 5 for Figure 2 Enlarged view of the structure at point B.

[0021] Figure 6 for Figure 3 Enlarged view of the structure at point C.

[0022] Figure 7 for Figure 6 A schematic diagram of the structure after the installation of the arch web members.

[0023] Figure 8 This is a schematic diagram of the arch rib support structure used in the vertical rotation construction method of the arch rib of the arch bridge, which is a preferred embodiment of the present invention.

[0024] Explanation of main component symbols 110. Arch rib; 112. Semi-arch structure; 113. Arch rib segment; 114. Arch seat; 130. Closure joint; 131. First closure joint; 132. Second closure joint; 133. First extension arm; 134. Second extension arm; 135. Arch crown web member; 140. Pier; 150. Old bridge; 200. Rotating tower; 210. Cable saddle pulley; 300. First anchor; 400. Low-position assembly support; 410. Arch rib support; 411. Support frame; 412. Positioning groove; 413. Base plate; 415. Backing plate; 500. Second anchor; 600. Longitudinal guy rope; 610. Rear guy rope of tower; 620. Front guy rope of tower; 700. Reinforcing beam; 800. Buckle cable; 900. Hydraulic lifting equipment. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0027] 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Please also see Figure 1 and Figure 3This invention provides a preferred embodiment of a method for vertically rotating the arch rib of an arch bridge. This method applies the vertical rotation method to water-related environments with limited terrain, expanding its applicability while reducing construction costs, improving efficiency, ensuring safety, and achieving efficient and high-quality installation of the arch rib of a steel pipe basket arch bridge in complex environments. In this embodiment, the constructed arch bridge is a basket arch bridge, with its arch rib 110 having a designed inclination angle in the vertical plane; and the arch bridge is a reconstruction of the old bridge 150 at its location. The arch rib 110 of the arch bridge includes two semi-arch structures 112, which are sequentially spliced ​​together by several arch rib segments 113. One end of each semi-arch structure 112 is connected to a hinge (not shown) on a corresponding arch seat 114, and the other end of each semi-arch structure 112 is provided with a closure joint 130 connecting to the other semi-arch structure 112. The method for vertically rotating the arch rib of the arch bridge includes the following steps: S1, Construction Preparation: First anchors 300 are pre-embedded on the abutments 140 on both sides of the arch bridge to form cable anchors. Low-position assembly supports 400 and rotating towers 200 are erected. Two sets of low-position assembly supports 400 are set for each of the two semi-arch structures 112. The two sets of low-position assembly supports 400 are respectively set at the support positions of the two semi-arch structures 112. Two rotating towers 200 are set for each of the two semi-arch structures 112. The two rotating towers 200 are respectively set between the first anchors 300 and the low-position assembly supports 400 on both sides of the arch bridge.

[0029] Specifically, please refer to the following: Figure 5 The first anchor 300 is an anchor seat welded from steel plates, etc. The support pile positions of the low-level assembly support 400 are determined according to the support position of the arch rib segment 113 of the arch bridge, and the low-level assembly supports 400 of the two half-arch structures 112 are constructed respectively. During the erection of the rotating tower 200, the bottom end of the rotating tower 200 is fixed to the pier cap 140 of the transition piers on both sides of the river channel of the arch bridge. The pier cap 140 of the transition piers is equipped with an arch seat 114. In addition, according to design requirements, the arch rib segment 113 of the steel pipe basket arch bridge is prefabricated in the factory.

[0030] Please see also Figure 8In this embodiment, considering the design inclination angle of the arch rib 110 in the vertical plane, an arch rib support 410 is provided at the top of the low-position assembly bracket 400. The arch rib support 410 includes a support frame 411 fixed to the top of the low-position assembly bracket 400 and a positioning groove 412 fixed to the support frame 411 for placing the arch rib segment 113. The positioning groove 412 can position the arch rib segment 113 in a preset inclined posture, ensuring the stability and positioning accuracy of the arch rib segment 113 during the assembly process. Specifically, the positioning groove 412 is formed by a base plate 413 and a backing plate 415. Both the base plate 413 and the backing plate 415 are fixedly connected to the support frame 411. The base plate 413 is inclined relative to the horizontal plane, and the backing plate 415 is vertically connected to the base plate 413.

[0031] In this embodiment, in step S1, second anchors 500 are pre-embedded on the abutments 140 on both sides of the arch bridge to form cable anchors. The second anchor 500 is an anchor seat welded from steel plates or the like. The second anchor 500 is located on the side of the corresponding rotating tower 200 facing away from the lower assembly support 400. In this embodiment, the second anchor 500 and the first anchor 300 are respectively located on two adjacent abutments 140, and the second anchor 500 is closer to the rotating tower 200 than the first anchor 300. When constructing the rotating tower 200, longitudinal guy ropes 600 are strung on the two rotating towers 200. The longitudinal guy ropes 600 include two rear guy ropes 610 and one front guy rope 620. One end of the two rear guy ropes 610 is connected to two second anchors 500 respectively, and the other end of the two rear guy ropes 610 is connected to the top of the two rotating towers 200 respectively. The two ends of the front guy rope 620 are connected to the top of the two rotating towers 200 respectively.

[0032] The foundation 140 with the first anchor 300 and the foundation 140 with the second anchor 500 are connected to the adjacent foundation 140 through the reinforcing beam 700 to improve stability and form a reliable cable anchor system.

[0033] S2, Low-level assembly of arch rib 110: The prefabricated arch rib segment 113 is transported to the corresponding low-level assembly bracket 400 for assembly to form two half-arch structures 112, and the lower ends of the two half-arch structures 112 are connected to the hinges on the corresponding arch seats 114.

[0034] In this embodiment, the old bridge 150 is used as a transport channel during the transportation of the prefabricated arch rib segment 113 to the corresponding low-level assembly support 400. The prefabricated arch rib segment 113 is transferred to one end of the old bridge 150 by land or water transport. Using transport equipment set on the old bridge 150, such as rail flatcars or beam transport vehicles, the arch rib segment 113 is transported longitudinally along the old bridge 150 to the low-level assembly position of the new bridge arch rib. This avoids rearranging the transport channel in the limited space and reduces the difficulty of equipment selection and the investment in temporary measures. Then, using hoisting equipment, the arch rib segment 113 transported to the low-level assembly position is hoisted sequentially onto the corresponding low-level assembly support 400 for assembly according to the design sequence.

[0035] Specifically, if the structure of the old bridge 150 meets the transportation load requirements, necessary structural reinforcement and protection treatment will be carried out on the old bridge 150. During transportation, the arch rib segment 113 is first transported to the construction site by water transport ship, and a self-propelled modular transport vehicle is placed on the bridge deck of the old bridge 150; then, a crawler crane is used to transfer the arch rib segment 113 from the transport ship to the transport vehicle of the old bridge 150. The transport vehicle travels along the longitudinal direction of the old bridge 150 to transport the arch rib segment 113 to the preset low-position assembly position.

[0036] When using hoisting equipment to sequentially hoist the arch rib segments 113 transported to the low-level assembly position onto the corresponding low-level assembly supports 400 for assembly, the crawler crane is first driven to a position near the arch rib 110 on the old bridge 150. The crawler crane's hook is then connected to the arch rib segments 113 on the old bridge 150 transport vehicle via steel wire rope. Subsequently, the crawler crane's hook slowly rises, lifting the arch rib segments 113 to gradually detach them from the transport vehicle. The crawler crane then transports the arch rib segments 113 on land to the arch rib support 410, ensuring they fall into the positioning grooves 412 of the arch rib support 410. After each arch rib segment 113 of the semi-arch structure 112 is hoisted into position, precise alignment and welding are performed to form the complete semi-arch structure 112. During this process, the assembly accuracy and alignment of the arch ribs 110 are monitored in real time using measurement and monitoring equipment to ensure assembly quality. When the lifting capacity and lifting radius of some arch rib segments 113 are limited by the crawler crane, they can be installed by lifting.

[0037] S3, Arch Rib 110 Rotation Construction: Please refer to [link / reference] as well. Figure 4 One end of the sling 800 is connected to the corresponding first anchor 300 via a hydraulic lifting device 900. The other end of the sling 800 is threaded through the cable saddle pulley 210 at the top of the rotating tower 200 and then connected to the free end of the corresponding semi-arch structure 112. The sling 800 is driven by the hydraulic lifting device 900 to rotate the corresponding semi-arch structure 112 vertically until it reaches the designed position. Then, the closure joint 130 of the two semi-arch structures 112 is connected together to achieve closure.

[0038] Please see also Figure 6 and Figure 7 In this embodiment, the closure joint 130 provided on one half-arch structure 112 is the first closure joint 131, and the closure joint 130 provided on the other half-arch structure 112 is the second closure joint 132. Both the first closure joint 131 and the second closure joint 132 include a first extension arm 133 and a second extension arm 134 extending from the free end of the corresponding half-arch structure 112 toward the other half-arch structure 112. The first extension arm 133 is located above the second extension arm 134. The extension length of the first extension arm 133 of the first closure joint 131 is greater than that of the second extension arm 134, and the extension length of the first extension arm 133 of the second closure joint 132 is less than that of the second extension arm 134. The first extension arm 133 of the first closure joint 131 is connected to the first extension arm 133 of the second closure joint 132, and the second extension arm 134 of the first closure joint 131 is connected to the second extension arm 134 of the second closure joint 132. When the arch rib 110 is assembled at a low position in step S2, the free end of the semi-arch structure 112 with the first closure joint 131 is positioned above the free end of the other semi-arch structure 112; in step S3, the vertical rotation of the corresponding semi-arch structure 112 by driving the buckle 800 through the hydraulic lifting device 900 includes the following steps: S31, the fastener 800 corresponding to the semi-arch structure 112 with the first closure joint 131 is installed; S32, perform vertical rotation of the semi-arch structure 112 with the first closure joint 131. After the rotation is in place, remove the part of the low-position assembly bracket 400 that obstructs the vertical rotation of the other semi-arch structure 112 corresponding to the semi-arch structure 112 with the first closure joint 131. S33, the fastener 800 corresponding to the semi-arch structure 112 with the second closure joint 132 is installed; S34, the semi-arch structure 112 equipped with the second closure joint 132 is vertically rotated. After the rotation is in place, the first extension arm 133 of the first closure joint 131 is connected to the first extension arm 133 of the second closure joint 132, and the second extension arm 134 of the first closure joint 131 is connected to the second extension arm 134 of the second closure joint 132. Subsequently, the arch top web member 135 is installed between the first extension arm 133 of the first closure joint 131 and the first extension arm 133 of the second closure joint 132, completing the vertical rotation installation of the arch rib 110. The hydraulic lifting equipment 900 can use a hydraulic lifting jack.

[0039] In the prior art, the closure joint 130 of the semi-arch structure 112 is usually designed with equal length, that is, the first extension arm 133 and the second extension arm 134 of the closure joint 130 of each semi-arch structure 112 have the same extension length. This structure causes the closure joint 130 of the semi-arch structure 112 that completes the vertical rotation first to obstruct the vertical rotation of the other semi-arch structure 112 during the installation of the arch rib 110, so that the semi-arch structure 112 cannot be vertically rotated into place in one go. When closing, the position of the closure joint 130 of the two semi-arch structures 112 needs to be adjusted at the same time to ensure that the closure joint 130 of the two semi-arch structures 112 can be smoothly connected. The vertical rotation construction method for the arch rib of the arch bridge of the present invention optimizes the closure joint 130 of the closure opening of the semi-arch structure 112. The first extension arm 133 and the second extension arm 134 of the closure joint 130 of the two semi-arch structures 112 have a differentiated structure of different lengths. During the installation of the arch rib 110, the vertical rotation of the semi-arch structure 112 corresponding to the first closure joint 131 with the longer first extension arm 133 is completed first, and then the vertical rotation of the semi-arch structure 112 corresponding to the second closure joint 132 with the shorter first extension arm 133 is carried out. In this process, due to the structural design of the first closure joint 131 with the longer first extension arm 133 and the shorter second extension arm 134, it will not obstruct the vertical rotation of the other semi-arch structure 112. Therefore, the semi-arch structure 112 can be vertically rotated into place in one go, improving construction efficiency. Furthermore, during the vertical rotation of the semi-arched structure 112 corresponding to the second closure joint 132, where the first extension arm 133 is shorter, the first extension arm 133 of the first closure joint 131 can also abut against the second extension arm 134 of the second closure joint 132, preventing the semi-arched structure 112 corresponding to the second closure joint 132 from rotating too much during the vertical rotation, thus effectively avoiding the risk of excessive tension on the rear vertical rotation side.

[0040] The vertical rotation construction method for arch ribs of arch bridges has the following advantages for vertical rotation construction of arch rib 110: (1) Reduce construction costs: By using the old bridge utilization technology, the existing bridge is transformed into an arch rib transportation channel, which reduces the construction cost of temporary transportation channels, while also reducing the difficulty of equipment selection and the demand for large transportation equipment, and reducing equipment rental and maintenance costs; by using the 140 pier of the new bridge as the anchor for the vertical rotation of the arch rib 110, the temporary anchor is eliminated, avoiding the cost of setting up a separate temporary anchor foundation, which effectively reduces construction costs.

[0041] (2) Improve construction efficiency: By transforming the existing bridge into an arch rib transportation channel, there is no need to replan and build the transportation channel in the restricted area, saving construction preparation time; by using the old bridge 150 to transport the arch rib segment 113, continuous transportation can be achieved, improving transportation efficiency; by using the new bridge pier 140 as a ground anchor, the preparation work for vertical rotation construction is simplified, the construction cycle is shortened, and the overall installation efficiency of the main arch of the steel pipe basket arch bridge is improved.

[0042] (3) Reduced investment in temporary measures: The construction of a large number of temporary transportation channels and temporary ground anchor foundations was reduced, which reduced the material consumption and manpower input of temporary measures, conformed to the concept of green construction, and reduced the follow-up work caused by the demolition of temporary measures.

[0043] (4) Precise control of the vertical rotation process: The differentiated design of the extension lengths of the first extension arm 133 and the second extension arm 134 of the closure joint 130 forms a tensioning limit mechanism, which can effectively avoid the risk of excessive tensioning on the vertical rotation side: Due to the differentiated design of the extension lengths of the first extension arm 133 and the second extension arm 134 of the closure joint 130, during the vertical rotation of the arch rib 110, the first extension arm 133 of the first closure joint 131 can serve as a natural limit for the tensioning stroke of the other half-arch structure 112, so that the operators can intuitively judge the tensioning progress and avoid tensioning overtravel due to operational errors or misjudgments, thereby reducing the cable retraction operation in the closure stage, reducing the risk of structural stress mutation and linear deviation caused by cable retraction, and ensuring the precise controllability of the vertical rotation process and construction safety.

[0044] (5) Enhanced structural stress performance: The asymmetrical arrangement of the first closure joint 131 and the second closure joint 132 can optimize the stress distribution of the closure section to a certain extent. Compared with the traditional equal-length joint design, the closure joint 130 of the present invention can more rationally distribute stress when subjected to closure stress, avoid local stress concentration, enhance the overall stress performance and durability of the closure structure, and thus improve the long-term safety and reliability of the bridge structure.

[0045] (6) Ensuring construction safety: It reduces the risk of complex transportation and equipment operation in a narrow space. At the same time, it utilizes the existing old bridge 150 and new bridge abutment 140 structures, which have higher structural reliability. Compared with temporary structures, it reduces the safety hazards caused by structural instability during construction and ensures the safety of construction personnel and equipment.

[0046] (7) Enhanced construction adaptability: In response to the complex construction environment restricted by waterway construction and site, this invention provides an effective solution, broadens the application scope of the "low-position assembly and vertical rotation into arch" process, and can ensure the smooth installation of the arch rib of the steel pipe basket arch bridge under various restricted conditions.

[0047] It is understood that the vertical rotation construction method for the arch ribs of the arch bridge of the present invention is not limited to the construction of the arch ribs of the basket arch bridge, but can also be used for the vertical rotation construction of the arch ribs of other types of arch bridges.

[0048] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for vertically rotating an arch rib of an arch bridge, wherein the arch rib comprises two semi-arch structures, the semi-arch structures being assembled sequentially from several arch rib segments, one end of each of the two semi-arch structures being connected to a hinge on a corresponding arch seat, and the other end of each semi-arch structure being provided with a closure joint for connection to the other semi-arch structure, characterized in that... The method for vertical rotation of the arch ribs of the arch bridge Includes the following steps: S1, Construction preparation: First anchors are pre-embedded on the piers on both sides of the arch bridge to form cable anchors. Low-position assembly supports and rotating towers are erected. Two sets of low-position assembly supports are set up corresponding to the support positions of the two semi-arch structures. Two rotating towers are set up corresponding to the two semi-arch structures. The two rotating towers are respectively set between the first anchors and the low-position assembly supports on both sides of the arch bridge. S2, Low-position assembled arch rib: The prefabricated arch rib segments are transported to the corresponding low-position assembly brackets for assembly to form two semi-arch structures, and the lower ends of the two semi-arch structures are connected to the hinges on the corresponding arch seats. S3, Arch Rib Rotation Construction: One end of the sling is connected to the corresponding first anchor through a hydraulic lifting device. The other end of the sling is threaded through the cable saddle pulley at the top of the corresponding rotating tower and then connected to the free end of the corresponding semi-arch structure. The sling is driven by the hydraulic lifting device to perform vertical rotation of the corresponding semi-arch structure until the design position is reached. Then the closure joint of the two semi-arch structures is connected together to achieve closure.

2. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 1, characterized in that, In step S1, second anchors are pre-embedded on the piers on both sides of the arch bridge to form guy ropes. The second anchors are located on the side of the corresponding rotating tower facing away from the low-position assembly support. When the rotating tower is erected, longitudinal guy ropes are pulled on the two rotating towers. The longitudinal guy ropes include two tower rear guy ropes and one tower front guy rope. One end of the two tower rear guy ropes is connected to the two second anchors, and the other end of the two tower rear guy ropes is connected to the top of the two rotating towers. The two ends of the tower front guy rope are connected to the top of the two rotating towers.

3. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 2, characterized in that, The bearing platform with the first anchor and the bearing platform with the second anchor are connected to adjacent bearing platforms by a reinforcing beam.

4. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 1, characterized in that, The closure joint provided on one half of the arch structure is the first closure joint, and the closure joint provided on the other half of the arch structure is the second closure joint. Both the first closure joint and the second closure joint include a first extension arm and a second extension arm extending from the free end of the corresponding half of the arch structure toward the other half of the arch structure. The first extension arm is located above the second extension arm. The extension length of the first extension arm of the first closure joint is greater than that of the second extension arm, and the extension length of the first extension arm of the second closure joint is less than that of the second extension arm. The first extension arm of the first closure joint is connected to the first extension arm of the second closure joint, and the second extension arm of the first closure joint is connected to the second extension arm of the second closure joint.

5. The vertical rotation construction method for the arch rib of an arch bridge as described in claim 4, characterized in that, In step S3, driving the buckle to vertically rotate the corresponding semi-arch structure using the hydraulic lifting device includes the following steps: Install the fastening cable corresponding to the semi-arch structure equipped with the first closure joint; The semi-arch structure with the first closure joint is rotated vertically. After the rotation is in place, the part of the low-level assembly bracket corresponding to the semi-arch structure with the first closure joint that obstructs the vertical rotation of the other semi-arch structure is removed. Install the fastening cable corresponding to the semi-arch structure equipped with the second closure joint; The semi-arch structure equipped with the second closure joint is vertically rotated. After the rotation is in place, the first extension arm of the first closure joint is connected to the first extension arm of the second closure joint, and the second extension arm of the first closure joint is connected to the second extension arm of the second closure joint. Then, the arch top web member is installed between the first extension arm of the first closure joint and the first extension arm of the second closure joint to complete the vertical rotation installation of the arch rib.

6. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 1, characterized in that, The arch bridge is constructed at the site of the old bridge. In step S2, the old bridge is used as a transport channel to transport the prefabricated arch rib segments to the corresponding low-level assembly supports. The prefabricated arch rib segments are transferred to one end of the old bridge by land or water transport. Using the transport equipment set on the old bridge, the arch rib segments are transported longitudinally along the old bridge to the low-level assembly position of the new bridge arch rib. Then, using hoisting equipment, the arch rib segments transported to the low-level assembly position are hoisted sequentially onto the corresponding low-level assembly supports for assembly according to the design sequence.

7. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 1, characterized in that, The top of the low-position assembly bracket is provided with an arch rib support member. The arch rib support member includes a support frame fixed to the top of the low-position assembly bracket and a positioning groove fixed to the support frame for placing the arch rib segment. The positioning groove can position the arch rib segment in a preset tilt posture.

8. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 7, characterized in that, The positioning groove is formed by a base plate and a backing plate. The base plate and the backing plate are both fixedly connected to the support frame. The base plate is inclined relative to the horizontal plane, and the backing plate is vertically connected to the base plate.

9. The method for vertical rotation construction of the arch rib of an arch bridge as described in claim 1, characterized in that, The bottom end of the rotating tower is fixed to the pier platform of the transition pier on both sides of the river of the arch bridge, and the arch seat is provided on the pier platform of the transition pier.

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