Erecting equipment for large-span half-through arch bridge crossing levee and construction method

Abstract

The invention discloses erecting equipment for a large-span half-through arch bridge stretching across a levee and a construction method. The erecting equipment comprises the steps that a gantry crane anti-sliding foundation containing pre-embedded uplift piles and saddle weights is constructed, a 120 t gantry crane with hydraulic drive liftable supporting legs is adopted to be arranged across the levee, and steel truss girders stretching to cover 16 sections of the Yifen side and 17 sections of the Chaohu side are erected; the included angle between the buckling tower wind cable and the horizontal direction is optimized to be 60-65 degrees, and a PT100 temperature sensor is additionally arranged at an arch rib closure opening to achieve precise closure; the matched erecting equipment comprises the gantry crane, a 100t arch climbing crane, a 400t. M tower crane, a position adjusting system and the like. By means of the structure and the method, the settlement amount of the levee is controlled within 0.5 mm, the channel passing rate is 100%, the construction period is shortened by 32 days or above compared with an existing scheme, the cable buckling force is reduced by 20%, meanwhile, the construction method adapts to the wide water level variable amplitude, is suitable for construction of the large-span half-through steel truss arch bridge which crosses the river levee and needs to guarantee channel navigation, and has ecological protection and engineering benefits.

Description

Technical Field

[0001] This invention relates to the field of arch bridge construction technology, specifically to an erection device and construction method for a long-span, mid-span arch bridge spanning a dike. Background Technology

[0002] As transportation infrastructure extends into complex geographical environments, long-span, mid-span arch bridges are widely used in engineering scenarios such as crossing rivers and dikes due to their strong spanning capacity and reasonable structural stress distribution. Taking the Nanfei River Bridge as an example, this bridge adopts a (108+312+108)m mid-span three-span continuous steel truss arch bridge, which needs to cross the Nanfei River dike. At the same time, the waterway at the bridge site is currently classified as Class II and planned to be Class I, so it is necessary to ensure the smooth flow of waterway during construction. In addition, the surrounding area is a wetland protection zone, and the requirements for dike structural stability and ecological protection are extremely high.

[0003] The existing construction technology for long-span, mid-span arch bridges across embankments has the following core problems: 1. Conflict between dike protection and construction coverage: Traditional solutions often adopt the "gantry crane inside the dike + cantilever assembly in the middle span" mode. The gantry crane is only placed on the inside of the dike and can only cover the 1st to 12th sections of the side span. The remaining sections of the middle span need to be assembled by cantilever cranes on the arch. The length of the cantilever section is more than 150m. This not only has a long construction period, but also requires the setting of temporary supports or increasing the tension of the cable during the cantilever assembly process. Temporary supports are prone to encroaching on the waterway, and excessive tension of the cable increases the structural safety risk. Another solution is to use heavy crawler cranes, but crawler cranes need to set up a working site on the outside of the dike. The dike has limited bearing capacity, and the rolling of heavy equipment can easily lead to dike settlement, which is difficult and costly to repair later. In addition, the operating radius of crawler cranes is limited and cannot cover all sections of the 312m main span in the middle span.

[0004] 2. Conflict between navigation and construction efficiency: Some existing technologies use temporary supports in the waterway to reduce the length of the cantilever section. However, with a daily traffic volume of over 300 vessels, these temporary supports reduce the clear width of the waterway (for example, the original Class II waterway required a clear width of ≥80m, but after the temporary supports are used, the clear width is only 60m), resulting in a decrease in navigation efficiency of over 30%. Furthermore, the temporary supports must withstand the impact of water flow, making them prone to displacement and affecting construction safety. Another option is to use "phased closure of navigation for construction," but this requires approval from the maritime authorities, and the closure period will cause economic losses to shipping companies and have a significant social impact.

[0005] 3. Poor adaptability to hydrological conditions: Some rivers have large water level fluctuations (normal water level 8.5-9.0m, 100-year flood level 13.36m, water level difference up to 4.86m). The existing gantry crane outriggers are mostly designed with a fixed height. When the water level rises, the outrigger foundation is easily submerged, causing equipment shutdown. When the water level drops, the outriggers do not make proper contact with the foundation, which easily leads to the risk of gantry crane overturning. Frequent adjustment of outrigger height is required, increasing construction costs and the risk of project delays.

[0006] In summary, existing technologies cannot achieve a balance between the four major requirements of "dike protection, navigation, hydrological adaptation, and construction efficiency." There is an urgent need for a construction technology that can cover dikes, not encroach on waterways, adapt to water level changes, and not damage dikes. Summary of the Invention

[0007] This application proposes an erection equipment and construction method for a large-span, mid-span arch bridge spanning a dike, aiming to solve the technical problem in the existing erection of large-span, mid-span arch bridges spanning dikes that makes it difficult to balance dike protection, navigation, and construction efficiency. Specifically, existing solutions either only deploy equipment inside the dike, resulting in long cantilever sections, long construction periods, and impact on navigation; or use heavy equipment to compact the dike, leading to dike damage; or cannot adapt to water level changes, resulting in a high risk of equipment downtime.

[0008] To achieve the above objectives, this application adopts the following technical solution: a method for erecting a long-span, mid-span arch bridge spanning a dike, comprising the following steps: S1: Construction of temporary access road, construction of bored piles, pile caps and pier bodies for piers 1-4, and construction of the foundation for a 120t gantry crane. The gantry crane foundation includes pre-embedded anti-uplift piles and counterweight blocks. The anti-uplift piles are inserted into the bearing layer of the dike foundation, and the counterweight blocks are cast integrally with the track foundation. Erect temporary supports for the side spans, install a 120t mast crane and the adjustment system for piers 1 and 4, and precast concrete bridge decks. S2: Install the 120t gantry crane, which includes liftable outriggers. Adjust the height of the liftable outriggers so that the elevation of the main beam of the gantry crane is more than 1.5m higher than the highest navigable water level. Use the gantry crane to install 1-2 sections of steel truss beam members and corresponding bridge decks. S3: Use the gantry crane to install and debug a 100t arch climbing crane, and simultaneously use the gantry crane to install 3-section steel truss members and corresponding bridge decks; S4: Use the gantry crane to erect the steel truss beam to the 8th section, use the arch climbing crane to install the side span concrete bridge deck and arch rib members to the 7th section, and install the permanent supports of the 2nd and 3rd main piers; S5: Use the gantry crane to install G10 member, adjust the posture of G10 member through the adjustment system to achieve side span pier, use the gantry crane to install the remaining steel truss members of the 9th section, and use the arch climbing crane to simultaneously install the arch rib members of the 7th section; S6: Use the gantry crane to erect the steel truss beam to the 12th section, and use the climbing arch crane to install the remaining members of the corresponding section; S7: Adjust the posture of the side span steel truss beam through the adjustment system, accurately adjust and grout the supports of the No. 2 and No. 3 main piers, temporarily lock the main pier supports, release the longitudinal constraint of the temporary support of the side pier, lift the side pier steel beam to free the temporary support, lower the steel beam and apply side span ballast, and dismantle the side span temporary support. S8: Use the gantry crane to erect the steel truss beam on side A to the 16th section and on side B to the 17th section. Use the climbing arch crane to simultaneously install the arch rib members and corresponding slings in the 14th section of the middle span. Install 400t.m tower cranes upstream and downstream of main piers #2 and #3. Use the tower cranes to install and tension the tower clamping system and wind cables. S9: Cantilever erection of arch rib segments, side span ballast, hook back cables and tensioning; S10: Use a 300t floating crane to dismantle the 120t gantry crane and its foundation; S11: Monitor the temperature of the arch rib closure joint, adjust the posture of the closure joint, complete the arch rib closure, and release the temporary limit of the main pier; S12: Adjust the posture of the steel truss girder closure joint, complete the steel truss girder closure, and install the bridge deck at the closure joint. S13: Unload the side span ballast in stages, lift the side pier support to the design elevation, construct the side pier support pad stone, adjust and grout the side pier support, lift the tower crane and dismantle the tower buckle system, retract the climbing arch crane and install auxiliary works, and dismantle the climbing arch crane. S14: Construction of the second phase of the permanent load and bridge deck ancillary facilities, and completion of the entire bridge erection.

[0009] Furthermore, in step S1, the anti-uplift piles have a diameter of 1.2-1.3m, a length of 15-16m, and a spacing of 3-3.2m along the gantry crane track direction. The counterweight blocks are made of C30-C35 concrete, with a single block weighing 5-6t.

[0010] Furthermore, in step S2, the liftable outrigger is hydraulically driven with a stroke of 1.5-1.8m and a maximum load capacity of 300-320t. The span of the gantry crane is 42-45m and the height is 40-42m.

[0011] Furthermore, in step S8, the angle between the wind cable of the tower-locking system and the horizontal direction is 60-65°, and the tension control force of the wind cable is 500-550kN.

[0012] Furthermore, in step S11, the temperature monitoring of the closure joint adopts a PT100 temperature sensor with a monitoring accuracy of ±0.1℃. During closure, the ambient temperature is controlled at 15-25℃, and the gap at the closure joint is controlled at 2-3mm.

[0013] Furthermore, in step S7, the side span ballast is made of precast concrete blocks with a ballast density of 55t / m and the ballast range is within 24m of the side spans of both large and small mileages. In step S10, the side span ballast is carried out in two stages: the second ballast is 100t and the third ballast is 150t, and the ballast location is between segments 2# and 3#.

[0014] Furthermore, in step S9, the cantilever arch rib segments include segments C15-G15-A16E16, C16-G16-A17E17, C17-C18G18-C19G19-G17-A18E18-A19E19 and C20G20-C21G21-C22G22-A20E20-A21E21-A22E22. When the back-clipping cables are tensioned, back-clipping cable #1 is tensioned to 60% of the design force, back-clipping cable #2 is tensioned to 70%, and back-clipping cable #3 is tensioned to 80%.

[0015] Furthermore, the equipment used for erecting the large-span, mid-span arch bridge spanning the dike includes a 120t gantry crane, a 100t climbing arch crane, a 400t.m tower crane, a tower clamping system, a 120t mast crane, and a positioning system. The 120t gantry crane includes a track, liftable outriggers, and a lifting beam mechanism. The track extends to the outside of the dike, and a foundation is provided below the track. The foundation includes pre-embedded anti-uplift piles and counterweights. The liftable outriggers are located below the main beam of the gantry crane, are hydraulically driven, and have a stroke of 1.5-1.8m. The tower clamping system includes the tower clamping body and wind cables, with the wind cables forming an angle of 60-65° with the horizontal direction. The positioning system is located at the No. 1 and No. 4 side piers and the No. 2 and No. 3 main piers, and includes vertical jacks and lateral correction devices.

[0016] Furthermore, the anti-tension pile has a diameter of 1.2-1.3m and a length of 15-16m; the counterweight is a C30-C35 concrete block, with a single block weighing 5-6t; the gantry crane has a span of 42-45m, a height of 40-42m, and a maximum lifting capacity of 120t. Furthermore, the wind cable of the tower clamping system is made of Φ28mm steel wire rope with a breaking strength ≥580kN, and the vertical jack of the positioning system is 320t class, and the horizontal correction device is 100t class.

[0017] The present invention has the following beneficial effects: 1. This application provides an erection equipment and construction method for a large-span, mid-span arch bridge spanning a dike. Through an anti-slip foundation structure of anti-tension piles and counterweight blocks, it achieves the function of preventing foundation slippage when the gantry crane operates across the dike and eliminating the need to excavate the main body of the dike. This solves the problems of dike settlement and high repair costs caused by heavy equipment rolling over the dike in the prior art. It achieves the technical effect of controlling the dike settlement within 0.5mm (meeting the requirements of SL 260-2014) and protecting the dike structure and the surrounding ecological environment of wetlands.

[0018] 2. This application provides an erection equipment and construction method for a large-span, mid-span arch bridge spanning a dike. By using a gantry crane (including liftable outriggers) structure arranged across the dike, it can cover multi-segment construction outside the dike and adapt to water level changes. This solves the problems of temporary piers encroaching on the waterway and interrupting navigation in existing solutions, and achieves the technical effect of 100% waterway traffic capacity, no impact on ship navigation, and avoidance of economic losses for shipping companies.

[0019] 3. This application provides an erection equipment and construction method for a large-span mid-span arch bridge spanning a dike. By extending the gantry crane across the dike to cover the 16 sections on the Hefei side and the 17 sections on the Chaohu side, the length of the mid-span cantilever section is shortened. This solves the problems of long construction period and high risk of high-altitude operation caused by excessively long cantilever sections in the existing technology. The technical effect is to shorten the mid-span cantilever section to 90m, shorten the construction period by more than 32 days compared with the existing scheme, and improve the continuity of construction by 25%.

[0020] 4. This application provides an erection equipment and construction method for a large-span, mid-span arch bridge spanning a dike. Through structural design optimization of the 60-65° angle of the anchor cable and monitoring by a PT100 temperature sensor at the closure joint, it achieves the functions of reducing the anchor cable tension and accurately controlling the closure posture. This solves the problem of high structural safety risks caused by excessive anchor cable tension and insufficient closure accuracy in the prior art. It achieves the technical effects of reducing the maximum anchor cable tension by 20%, controlling the closure accuracy to 2-3mm (complying with the requirements of JTG / T 3650-2020 standard), and increasing the structural safety factor by 15%. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, illustrate embodiments disclosed in this application and, together with the specification, serve to explain the principles disclosed in this application.

[0022] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 This is a schematic diagram of step one of this application; Figure 2 This is a schematic diagram of step two of this application; Figure 3This is a schematic diagram of step three of this application; Figure 4 This is a schematic diagram of step four of this application; Figure 5 This is a schematic diagram of step five of this application; Figure 6 This is a schematic diagram of step six of this application; Figure 7 This is a schematic diagram of step seven of this application; Figure 8 This is a schematic diagram of step eight of this application; Figure 9 This is a schematic diagram of step nine of this application; Figure 10 This is a schematic diagram of step ten of this application; Figure 11 This is a schematic diagram of step eleven of this application; Figure 12 This is a schematic diagram of step twelf of this application; Figure 13 This is a schematic diagram of step thirteen of this application; Figure 14 This is a schematic diagram of step fourteen of this application; Figure 15 This is a schematic diagram of step fifteen of this application; Figure 16 This is a schematic diagram of step sixteen of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] The side span steel truss girders were assembled and erected using scaffolding. The 120t gantry crane track extended to the outside of the embankment, with a 95m waterway reserved in the river. The gantry crane was 42m wide and about 40m high. It was used to assemble the steel truss girders of sections 1-16 on side A and install the corresponding upper and lower bridge decks. On side B, the gantry crane completed the assembly of steel truss girders of sections 1-17 and the installation of the corresponding upper and lower bridge decks. The gantry crane was dismantled using a 300t floating crane. After section 2 was installed, the gantry crane was used to install the arch crane. The steel truss arches of sections 6-17 were installed using a 100t arch crane. The remaining mid-span steel truss girders and steel truss arches were erected using cantilever assembly and inclined cable-stayed method. After the steel truss girders and steel truss arches were joined, the slings were installed. The steel truss arches were joined first, followed by the steel truss girders.

[0025] Step 1: Construction preparation, foundation construction, and installation of auxiliary facilities for the side spans: 1. Construct temporary access roads downstream of sides A and B (access roads are 6m wide, hardened with C20 concrete, and 20cm thick), extending the access roads 3m inside the embankment to avoid encroaching on the main body of the embankment.

[0026] 2. Construction of bored piles for piers 1-4 (8 Φ1.5m bored piles for side piers 1 and 4, and 12 Φ2.0m bored piles for main piers 2 and 3, with a pile length of 60m and concrete strength of C35), pile caps (side pier pile caps 10.1m×9.1m×3m, main pier pile caps 18.2m×13.2m×4m), and pier bodies (side pier columns 4.5m×4m, main pier columns 7.0m×5.0m, all with 0.5m rounded corners); the bearing pads for each pier will not be poured yet.

[0027] 3. Erect temporary supports for the side spans (using Φ609×16mm steel pipe piles, with a horizontal spacing of 3m and a longitudinal spacing of 6m, and an I40b I-beam distribution beam at the top); erect the construction platform and mast crane foundation; construct the foundation for the 120t gantry crane—arrange the gantry crane track (using P50 steel rails, with a sleeper every 2m) along the outer side of the embankment parallel to the bridge axis, and install anti-slip foundations under the track: ① Pre-embed anti-tension piles (Φ1.2-1.3m, length 15-16m, spacing 3-3.2m, concrete strength C35, single pile anti-tension bearing capacity ≥500kN), penetrating into the bearing layer of the embankment foundation (silty clay layer, bearing capacity characteristic value fak=200kPa); ② Pour counterweight blocks (C30-C35 concrete, size 2m×2m×1.5m, single block weight 5-6t) on top of the anti-tension piles, with the counterweight blocks and track foundations poured as a whole to prevent the gantry crane from sliding laterally. The anti-slip structure using anti-tension piles and counterweight blocks prevents foundation slippage caused by horizontal forces (such as wind force and horizontal loads during gantry crane operation across the dike. At the same time, it eliminates the need to excavate the main dike structure, protecting the dike structure, and the settlement can be controlled within 0.5mm. A 120t mast crane (maximum lifting capacity 120t, working radius 15-30m) and a positioning system for No. 1 and No. 4 side piers are installed (including vertical jacks: 320t class, and horizontal correction devices: 100t class).

[0028] 4. Install the adjustment system for side piers #1 and #4.

[0029] 5. Precast and store concrete bridge deck panels (the side span composite bridge deck uses C50 steel fiber reinforced concrete, 25cm thick, with a single panel size of 6m×3m, and a precast curing time of ≥28 days). This provides support for the installation of the initial segment of the side span, and the positioning system is used for subsequent steel truss girder attitude adjustment to ensure installation accuracy.

[0030] Step Two: Gantry Crane Installation and Initial Segment Erection: 1. Install a 120t gantry crane (span 42-45m, height 40-42m, maximum lifting capacity 120t, lifting height 30m). The gantry crane's main beam is equipped with liftable outriggers—the outriggers are hydraulically driven (model SY-320, working pressure 31.5MPa), with a stroke of 1.5-1.8m. The bottom of the outriggers is equipped with anti-slip pads (rubber material, friction coefficient ≥0.6). Adjust the outrigger height according to the construction water level (e.g., the normal water level of the Nanfei River is 8.5m) to ensure the gantry crane's main beam elevation is at least 1.5m higher than the highest navigable water level (12.64m) to avoid affecting navigation.

[0031] 2. Use a 120t gantry crane to install the steel truss members in sections 1 and 2 (such as sections A1E1-A2E2, weighing 102.15t).

[0032] 3. Use a 120t gantry crane to install the bridge deck panels of sections 1 and 2 (side span combined bridge deck, single panel weight 30t).

[0033] The adjustable outriggers can adapt to different water level changes (e.g., when the flood level is 13.36m, the outriggers can be raised to the maximum travel of 1.8m to ensure that the main beam is not submerged), eliminating the need for frequent disassembly and assembly of equipment and improving the continuity of construction; the gantry crane is arranged across the dike, directly covering the segments outside the dike, reducing the length of subsequent cantilever assembly.

[0034] Step 3: Installation of the arch-climbing crane and erection of the 3-section structure 1. A 120t gantry crane was used to install a 100t arch-climbing crane (maximum lifting capacity 100t, traveling speed 0.5m / min). The arch-climbing crane was tested under no-load conditions (lifting, luffing, and traveling motion tests) and test lifting (using a 50t test weight to test braking performance).

[0035] 2. A 120t gantry crane was used to simultaneously install the steel truss members of the third section (such as section A3E3, weighing 65.07t) and the corresponding bridge deck.

[0036] The arch-climbing crane is used for subsequent arch rib installation. Trial lifting ensures equipment safety, while the gantry crane simultaneously erects segments to improve construction efficiency.

[0037] Step 4: Collaborative Erection of Middle and Side Segments 1. Use a 120t gantry crane to erect the steel truss to the 8th section (e.g., section A8, weighing 86.4t). During the erection process, the elevation is re-measured every 3 sections (using a total station: accuracy ±2mm, and a level: accuracy ±1mm).

[0038] 2. A 100t arch-climbing crane was used to install the concrete bridge deck of the side span and the arch rib members up to the 7th section (e.g., the C7 arch rib section, weighing 24.71t).

[0039] 3. A 120t gantry crane was used to install the permanent supports (model GPZ(Ⅱ)5000DX, design bearing capacity 5000kN, support pad stone made of C50 concrete, thickness 30cm) and the adjustment system for the No. 2 and No. 3 main piers.

[0040] Because the gantry crane covers up to the 8th section, the starting point for the mid-span cantilever assembly is reduced, and the arch ribs are installed simultaneously by the climbing arch crane, thus achieving coordinated construction of the beam and arch.

[0041] Step 5: Complete the side span upper pier and 9 segments: 1. A 120t gantry crane was used to install the G10 rod (weighing 97.78t).

[0042] 2. Use the No. 1 and No. 2 pier adjustment systems to adjust the posture of G10 members (vertical elevation error ≤ 3mm, lateral deviation ≤ 2mm) to complete the A side span upper pier.

[0043] 3. The orientation of the G10 member was adjusted using the positioning system of pier #4 and pier #3 to complete the pier on side span B.

[0044] 4. Use a 120t gantry crane to install the remaining members of the 9th steel truss girder (such as segment A9E9, weighing 65.68t).

[0045] 5. Use a 100t arch-climbing crane to synchronously install the 7th arch rib member (such as the G7 arch rib segment, weighing 68.08t).

[0046] The completion of the main structure of the side span on the upper pier marks the completion of the side span, laying the foundation for the subsequent construction of the middle span. The simultaneous installation of the arch ribs reduces the interval between processes.

[0047] Step Six: Erection of 12-Segment and Installation of Additional Members: 1. Use a 120t gantry crane to erect the steel truss beam up to the 12th section (e.g., section A12, weighing 97.62t).

[0048] 2. A 100t arch crane was used to simultaneously install it to the 10th section of the arch rib.

[0049] 3. Use the arch-climbing crane to install the remaining members of the corresponding section (such as web members and horizontal bracing, weighing 15-20t / piece).

[0050] The gantry crane covers 12 sections, and the mid-span cantilever section is further shortened to within 180m, reducing the difficulty of subsequent cantilever assembly.

[0051] Step 7: Main pier support fixing and temporary scaffolding removal: 1. A 100t arch crane was used to install the 12th section of the member.

[0052] 2. The posture of the steel truss beam on side span A is adjusted using the positioning system of piers #1 and #2 (vertical pre-camber setting: side span L / 5000, middle span L / 4000, where L is the span); the supports of main piers #2 and #3 are precisely positioned (elevation error ≤1mm, plane position error ≤2mm) and grouted (using CGM-4 type non-shrink grout, compressive strength ≥60MPa / 28d); the support at main pier #2 (using Φ32mm precision rolled threaded steel, tension control force 100kN) is temporarily locked, the temporary support at side pier #1 is longitudinally released, and the temporary support on the downstream side is laterally limited.

[0053] 3. The B-side span steel truss beam posture was adjusted using the No. 4 and No. 3 pier adjustment systems; the No. 3 main pier support was precisely adjusted and grouted; the No. 4 main pier support was temporarily locked, the No. 1 side pier temporary support was longitudinally released, and the downstream side temporary support was laterally limited.

[0054] The steel beam at side pier #4.1 was jacked up (using 320t jacks, jacking in stages, with each stage lifting ≤5mm) to detach the temporary pier on side A (to detach the temporary support). The steel beam at side pier #4 was jacked up to detach the temporary support on side B.

[0055] 5. The steel beams are lowered, and the side spans are then loaded with precast concrete blocks (with a loading density of 55t / m³, and the loading range is within 24m of the side spans of both the large and small mileages).

[0056] 6. Dismantle the temporary support system for the side span (dismantle in sections, first dismantle the distribution beams, then dismantle the steel pipe piles to avoid concentrated unloading).

[0057] The main pier supports provide stable support for the mid-span cantilever construction, the side spans balance the overturning moment generated by the mid-span cantilever construction, and the temporary supports are removed to reduce structural interference.

[0058] Step 8: Erection and installation of the mid-span large segment: 1. Use a 120t gantry crane to install the steel truss girder on side A up to the 16th main girder section (e.g., A16E16 section, weighing 50.13t), and install the main girder on side B up to the 17th main girder section (e.g., A17E17 section, weighing 50.13t). At this time, the gantry crane's coverage area spans the dike, and the remaining cantilever section in the middle span is only 90m (the reserved channel width is 95m, which meets the Class I waterway's 150m clear width requirement), so there is no need to set up temporary supports.

[0059] 2. Using a 100t arch crane, continue to install the 14th section of the mid-span and the arch rib members (such as the C14 arch rib segment, weighing 31.62t) synchronously. The slings at the corresponding nodes (using Φ15.24mm steel strand with a breaking strength ≥260kN) are hoisted together with the arch rib members. The slings are pre-tensioned to 30% of the design cable force during installation.

[0060] 3. Install one 400t.m tower crane (model QTZ800, working radius 50m, maximum lifting capacity 80t) upstream and downstream of the No. 2 and No. 3 main piers respectively.

[0061] 4. A 400t.m tower crane is used to install the tower clamping system (the tower clamping system uses Φ800×20mm steel pipe and is 50m high), and the first wind cable (using Φ28mm steel wire rope with a breaking strength ≥580kN) is installed and tensioned simultaneously; the wind cable tensioning control force is 500-550kN (using a 500t-class tensioning jack with an accuracy of ±1%).

[0062] The gantry crane covers 16-17 segments, and the mid-span cantilever section is shortened to 90m, eliminating the need for temporary supports and ensuring 100% navigation of the waterway; the optimized angle of the tower-mounted wind cable (traditional angle 50-55°) can reduce the cable tension by 20%, reducing the risk of structural stress.

[0063] Step Nine: Cantilever Erection 1 1. Cantilever erection of C15, G15, A16E16 arch rib sections (C15 weighs 28.63t, G15 weighs 57.60t).

[0064] 2. The tower crane is simultaneously lifted and the tower is installed. The corresponding second and third wind cables are simultaneously installed and tensioned.

[0065] 3. After the tower crane is installed, lower the tower crane section to its free height.

[0066] 4. Use a 300t floating crane (model QY300V, maximum lifting capacity 300t, working radius 18m) to dismantle a 120t gantry crane: first dismantle the main beam (divided into 3 sections, each weighing 50t), then dismantle the outriggers (each outrigger weighs 30t), and finally dismantle the rails and foundation.

[0067] The gantry crane should be dismantled promptly after its erection is completed to avoid occupying waterway space. The floating crane can be dismantled without the need for land sites, thus adapting to the river environment.

[0068] Step 10: Cantilever erection two: 1. The C16 and G16 arch rib sections are cantilevered on side A, and the C17 and G17 arch rib sections are cantilevered on side B.

[0069] 2. Perform a second round of compaction between segments #2 and #3 (second round of compaction: 100t).

[0070] 3. Attach the No. 1 back cable and complete the tensioning. Tension the No. 1 back cable to 60% of the design force.

[0071] 4. Remove the foundation of the gantry crane support.

[0072] Step 11: Cantilever erection three: 1. Cantilever erection of sections C17, C18G18, C19G19, G17, A18E18A, and 19E19.

[0073] 2. A third loading is carried out between segments #, with a loading weight of 150t.

[0074] 3. Attach the No. 2 back cable and complete the tensioning. Tension the No. 2 back cable to 70%.

[0075] Step Twelve: Cantilever Erection Four 1. Cantilever erection of sections C20G20, C21G21, C22G22, A20E20, A21E21, and A22E22.

[0076] 2. Attach the No. 3 back cable and complete the tensioning. Tension the No. 3 back cable to 80%.

[0077] Step Thirteen: Arch Rib Closure I: 1. Install PT100 temperature sensors (accuracy ±0.1℃) on both sides of the arch rib closure joint to monitor the temperature of the closure joint in real time. When the ambient temperature is stable at 15-25℃ (daily average temperature difference ≤5℃), the closure will be carried out.

[0078] 2. The arch-climbing crane on side B travels to section 22 and sequentially lifts the lower chord (weighing 56.45t), diagonal web member (weighing 20t), and upper chord (weighing 25t) of the arch rib closure section to connect with node 22 on side B.

[0079] 3. Using the side support points to lower the beam (320t jacks, graded lowering amount ≤2mm) and the longitudinal adjustment of the main pier (100t transverse correction device), the arch rib closure position is precisely adjusted to control the closure gap to 2-3mm. The closure section is then welded (using CO2 gas shielded welding, welding wire type ER50-6, welding current 200-250A, voltage 25-30V) to complete the arch rib closure.

[0080] 4. Release the temporary restraints on the No. 2 main pier.

[0081] Temperature monitoring ensures stable structural deformation during closure, preventing temperature stress from causing cracks in the closure joint. The closure accuracy is controlled within 2-3mm, meeting the requirements of the specifications (JTG / T 3650-2020 "Technical Specifications for Highway Bridge and Culvert Construction").

[0082] Step Fourteen: Arch Rib Closure II 1. The arch-climbing crane on side B moves to section 22# and sequentially lifts and installs the arch rib closure section members C23G23 to connect with node 22# on side B. The upper and lower horizontal connections of the main arch are not installed.

[0083] 2. By adopting measures such as side support point jacking and main pier longitudinal adjustment, the posture of the arch rib closure opening was precisely adjusted to complete the arch rib closure.

[0084] 3. Release the temporary longitudinal bridge restriction on the No. 2 main pier.

[0085] Step 15: Installation of ancillary facilities and removal of equipment: 1. Gradual unloading of side spans (unloading amount ≤ 50t per day to avoid sudden changes in structural stress).

[0086] 2.1# and 3# side pier support points are jacked up to the design elevation (using 320t jacks, jacked up to the design elevation and then locked), and the side pier support pad stones (C50 concrete, 20cm thick) are constructed.

[0087] 3. Precise positioning and grouting of the side pier supports (CGM-4 type grouting material).

[0088] 4. Lift the upstream and downstream tower cranes (fix them every 5m), and dismantle the tower clamping system (dismantle in sections, first remove the wind cables, then dismantle the main body of the tower clamping system).

[0089] 5. The arch-climbing crane retracts (traveling speed 0.3m / min), and ancillary works are installed simultaneously during the process (such as guardrails: Φ114×4.5mm steel pipes, electrical lighting brackets: I14 I-beams).

[0090] 6. Dismantling of the arch-climbing crane.

[0091] Unloading the counterweights and adjusting the supports brought the structural stress back to the design state, and the installation of auxiliary works laid the foundation for subsequent bridge deck construction.

[0092] Step Sixteen: The entire bridge is completed. The second phase of construction includes the permanent load (including bridge deck paving: asphalt concrete, 10cm thick; crash barriers: C30 concrete, 1.2m high) and bridge deck ancillary facilities (traffic signs and markings: hot-melt paint, 1.5mm thick; signal monitoring equipment: cameras, radar speedometers; electrical lighting and illumination: LED streetlights, 150W power), full bridge inspection (load test: static load test using a 55t truck, deflection test accuracy ±0.1mm; visual inspection: crack width ≤0.15mm), completing the entire bridge construction.

Claims

1. A method for erecting a long-span, mid-span arch bridge spanning a dike, characterized in that, Includes the following steps: S1: Construction of temporary access road, construction of bored piles, pile caps and pier bodies for piers 1-4, and construction of the foundation for a 120t gantry crane. The gantry crane foundation includes pre-embedded anti-uplift piles and counterweight blocks. The anti-uplift piles are inserted into the bearing layer of the dike foundation, and the counterweight blocks are cast integrally with the track foundation. Erect temporary supports for the side spans, install a 120t mast crane and the adjustment system for piers 1 and 4, and precast concrete bridge decks. S2: Install the 120t gantry crane, which includes liftable outriggers. Adjust the height of the liftable outriggers so that the elevation of the main beam of the gantry crane is more than 1.5m higher than the highest navigable water level. Use the gantry crane to install 1-2 sections of steel truss beam members and corresponding bridge decks. S3: Use the gantry crane to install and debug a 100t arch climbing crane, and simultaneously use the gantry crane to install 3-section steel truss members and corresponding bridge decks; S4: Use the gantry crane to erect the steel truss beam to the 8th section, use the arch climbing crane to install the side span concrete bridge deck and arch rib members to the 7th section, and install the permanent supports of the 2nd and 3rd main piers; S5: Use the gantry crane to install G10 member, adjust the posture of G10 member through the adjustment system to achieve side span pier, use the gantry crane to install the remaining steel truss members of the 9th section, and use the arch climbing crane to simultaneously install the arch rib members of the 7th section; S6: Use the gantry crane to erect the steel truss beam to the 12th section, and use the climbing arch crane to install the remaining members of the corresponding section; S7: Adjust the posture of the side span steel truss beam through the adjustment system, accurately adjust and grout the supports of the No. 2 and No. 3 main piers, temporarily lock the main pier supports, release the longitudinal constraint of the temporary support of the side pier, lift the side pier steel beam to free the temporary support, lower the steel beam and apply side span ballast, and dismantle the side span temporary support. S8: Use the gantry crane to erect the steel truss beam on side A to the 16th section and on side B to the 17th section. Use the climbing arch crane to simultaneously install the arch rib members and corresponding slings in the 14th section of the middle span. Install 400t.m tower cranes upstream and downstream of main piers #2 and #3. Use the tower cranes to install and tension the tower clamping system and wind cables. S9: Cantilever erection of arch rib segments, side span ballast, hook back cables and tensioning; S10: Use a 300t floating crane to dismantle the 120t gantry crane and its foundation; S11: Monitor the temperature of the arch rib closure joint, adjust the posture of the closure joint, complete the arch rib closure, and release the temporary limit of the main pier; S12: Adjust the posture of the steel truss girder closure joint, complete the steel truss girder closure, and install the bridge deck at the closure joint. S13: Unload the side span ballast in stages, lift the side pier support to the design elevation, construct the side pier support pad stone, adjust and grout the side pier support, lift the tower crane and dismantle the tower buckle system, retract the climbing arch crane and install auxiliary works, and dismantle the climbing arch crane. S14: Construction of the second phase of the permanent load and bridge deck ancillary facilities, and completion of the entire bridge erection.

2. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S1, the anti-uplift piles have a diameter of 1.2-1.3m, a length of 15-16m, and a spacing of 3-3.2m along the gantry crane track. The counterweight blocks are made of C30-C35 concrete, with a single block weighing 5-6t.

3. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S2, the liftable outrigger is hydraulically driven with a stroke of 1.5-1.8m and a maximum load capacity of 300-320t. The span of the gantry crane is 42-45m and the height is 40-42m.

4. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S8, the angle between the wind cable of the tower-locking system and the horizontal direction is 60-65°, and the tension control force of the wind cable is 500-550kN.

5. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S11, the temperature monitoring of the closure joint uses a PT100 temperature sensor with a monitoring accuracy of ±0.1℃. During closure, the ambient temperature is controlled at 15-25℃, and the gap at the closure joint is controlled at 2-3mm.

6. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S7, the side span ballast is made of precast concrete blocks with a ballast density of 55t / m and the ballast range is within 24m of the side spans of both large and small mileage. In step S10, the side span ballast is carried out in two stages: the second ballast is 100t and the third ballast is 150t. The ballast location is between segments #2 and #3.

7. The method for erecting a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, In step S9, the cantilever arch rib segments include segments C15-G15-A16E16, C16-G16-A17E17, C17-C18G18-C19G19-G17-A18E18-A19E19 and C20G20-C21G21-C22G22-A20E20-A21E21-A22E22. When the back-clipping cables are tensioned, back-clipping cable #1 is tensioned to 60% of the design force, back-clipping cable #2 is tensioned to 70%, and back-clipping cable #3 is tensioned to 80%.

8. The erection equipment for a long-span, mid-span arch bridge spanning a dike according to claim 1, characterized in that, The system includes a 120t gantry crane, a 100t arch-climbing crane, a 400t.m tower crane, a tower clamping system, a 120t mast crane, and a positioning system. The 120t gantry crane includes a track, liftable outriggers, and a lifting beam mechanism. The track extends to the outside of the embankment, and a foundation is located beneath the track, including pre-embedded anti-uplift piles and counterweights. The liftable outriggers are located below the main beam of the gantry crane, are hydraulically driven, and have a stroke of 1.5-1.8m. The tower clamping system includes the tower clamping body and wind cables, with the wind cables forming an angle of 60-65° with the horizontal direction. The positioning system is located at side piers #1 and #4, and main piers #2 and #3, and includes vertical jacks and lateral correction devices.

9. The erection equipment for a long-span, mid-span arch bridge spanning a dike according to claim 8, characterized in that, The anti-uplift pile has a diameter of 1.2-1.3m and a length of 15-16m. The counterweight is a C30-C35 concrete block with a single block weight of 5-6t. The gantry crane has a span of 42-45m, a height of 40-42m, and a maximum lifting capacity of 120t.

10. The erection equipment for a long-span, mid-span arch bridge spanning a dike according to claim 8, characterized in that, The wind cable of the tower clamping system is made of Φ28mm steel wire rope with a breaking strength ≥580kN. The vertical jack of the positioning system is 320t class, and the horizontal correction device is 100t class.

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