Construction method of large-span prefabricated erection steel-concrete composite beam

Abstract

The application discloses a construction method of a large-span prefabricated erecting steel-concrete composite beam, which comprises the following steps: S1, annular trestle construction, S2, assembling support construction, S3, lifting station construction, S4, pier top bracket construction, S5, steel slot beam jacking construction, S6, bridge deck slab erection, S7, bridge deck slab superposition construction, and system conversion of the steel-concrete composite beam is completed; the method comprises the following steps: firstly, a bidirectional synchronous jacking construction technology is adopted to complete the erection of the steel slot beam, then a bridge deck slab machine is used to lay prefabricated bridge deck slabs, finally, the superposition of the bridge deck slabs and the steel beam is completed through beam jacking and falling in a unit of a bridge deck slab, the system conversion is completed, and the combined construction method of jacking first, erecting slabs second and superpositioning last is realized; compared with the conventional whole-hole hoisting method, the method does not need to carry out a large amount of dredging, does not need to long-term invest in multiple super-large equipment, does not need to set connecting plates on the top of each pier, only needs to invest in certain jacking equipment and the slab machine, the process is more compact, and the construction efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bridge erection technology, in particular to a large-span prefabricated erection steel-concrete composite beam construction method. BACKGROUND

[0002] Niutianyang Expressway Project is an important part of the expressway network in the Shantou City Overall Planning and the Shantou City Comprehensive Transportation System Development Long-term Planning (2012-2030). The project is located in the west of Shantou City, connected with Shantou-Kunming Expressway in the north and Shantou-Zhanjiang Expressway in the south, crossing the Rongjiang River and connecting the Sanyuwei and Niutianyang.

[0003] The water approach bridge of Niutianyang Bridge is divided into the north shore water approach bridge and the south shore water approach bridge, with a total length of 1.746 km. The north shore water approach bridge is from 0# pier to 20# pier, with a total length of 1.396 km; the south shore water approach bridge is from 25# pier to 30# pier, with a total length of 0.35 km. The general method for the sea-crossing bridge is to prefabricate the steel-concrete composite beam in the rear field, transport it to the designed position by using large-scale transportation equipment, finally hoist the whole hole by using large-scale hoisting equipment, and drop it on the temporary pier top support, finally weld the pier top steel beam connecting section and pour the pier top wet joint to complete the system conversion from simple support to continuous beam.

[0004] The project is located in the shallow area of the gulf in Shantou City, where the high and low tides are frequent; the water approach bridge adopts the scheme of separate beams and shared piers, with the track beam below and the left and right highway beams above, and each single hole has 3 pieces of composite beam, and the whole bridge has a total of 75 pieces of composite beam. The general method needs to dredge a large amount of silt in the shallow area to open the transportation channel, and needs to invest in multiple large-scale equipment for a long time, which is high in construction cost and slow in construction period. SUMMARY

[0005] Therefore, the present application aims to provide a large-span prefabricated erection steel-concrete composite beam construction method.

[0006] In order to solve the above technical problems, the technical scheme of the present application is as follows: a large-span prefabricated erection steel-concrete composite beam construction method, comprising the following steps:

[0007] S1, ring-shaped trestle construction;

[0008] S2, assembly support construction; the north shore steel trough beam assembly support is located at 9#-11# pier, which is used as the operation platform for temporary storage, linear adjustment, welding, painting and jacking of the steel beam; the assembly support structure process is to insert and drive steel pipe piles, install the inter-pile connection system, install the pile top distribution beam, install the longitudinal Bailey beam, install the transverse distribution beam, install the operation platform, track, jack and cushion block; each steel trough beam assembly support is composed of a highway steel trough beam assembly support and a track steel trough beam assembly support, the inter-pile connection system is arranged between the steel pipe piles of each assembly support, and the same longitudinal slope as the steel beam is arranged on the top of the assembly support;

[0009] S3, lifting station construction; the lifting station and the overhead traveling crane form a portal type hoisting device, which is mainly used for hoisting steel trough girder, frame plate components and precast bridge deck; the lifting station is located at the 10# pier, adopts pipe pile + distribution beam structure, the overhead traveling crane beam is arranged transversely across the bridge, with a width of 52m and a height of 43m above the top surface of the pile cap, can move 25m along the longitudinal direction of the bridge, the rated lifting capacity is 120t, the track longitudinal slope should not be greater than 1%, the construction process of the lifting station is as follows: inserting and driving steel pipe pile, installing inter-pile connecting system, installing longitudinal and transverse distribution beams on the top of the pile, installing attached wall, installing transverse overhead traveling crane beam, installing overhead traveling crane, and finally conducting trial lifting;

[0010] S4, pier top bracket construction; the pier top bracket is a non-floor type truss support structure, the lower part is a triangular truss structure, and the upper part is a longitudinal and transverse distribution beam + panel, which is anchored and connected with the concrete pier body through pre-buried climbing cone; the pier top bracket needs to be installed on the top of most piers except the 10# pier in the middle.

[0011] S5, steel trough girder jacking construction; the steel beam hoisting, linear adjustment, welding construction, painting construction, jacking construction and linear adjustment of the whole after jacking are sequentially and circularly conducted for each steel beam segment, all steel beams are jacked to the designed pier position, then the last 3 segments of steel trough girder are assembled in situ, finally the steel beam is lowered to the designed elevation in a unit of one span, and the steel beam erection of the whole bridge is completed;

[0012] S6, bridge deck erection;

[0013] S7, bridge deck superposition construction; the jacking and lowering of the composite beam are realized by the jacks arranged on the pier top, the steel beam is jacked to the designed height according to the principle of jacking the middle pier first and then the two sides, then the wet joints in the central positive bending moment area and the wet joints in the negative bending moment area on the pier top are sequentially poured, after the curing and tensioning of the wet joints are completed, the composite beam is lowered to the designed elevation, and the system conversion of the steel and concrete composite beam is completed;

[0014] S8, completion of steel and concrete composite beam system conversion.

[0015] As preferred, the steel trough girder jacking construction of S5 includes the following steps:

[0016] S51, step jacking installation; the approach bridge in water adopts the form of layered and combined construction, including left and right highway beams and track beams, 2 step jacking devices are arranged for each single span, 6 step jacking devices are arranged for each single pier, the height and plane position of the step jacking device should be installed according to the design requirements, the axis of the step jacking device and the two side piers should be parallel to the design axis of the steel beam, and the installation process of the step jacking device is as follows: installing the surface for leveling, installing the step jacking device and the upper distribution beam, installing the two side piers and the upper distribution beam, and connecting all pipelines;

[0017] S52, steel guide beam installation; in order to reduce the length and deflection of the steel trough beam cantilever during the pushing process, and to guide the beam body, a steel guide beam with a length of 50 m is arranged at the front end of the steel trough beam, which is a truss structure, and makes full use of the main trestle and the ring-shaped trestle, and is hoisted to the designated position in sections by the crawler crane for assembly;

[0018] S53, first hole steel trough beam pushing; the steel beam first hole pushing strictly follows the calculation steps, assembles the corresponding sections, and pushes the corresponding distance until the guide beam upper pier;

[0019] S54, non-first hole steel beam pushing; the non-first hole steel beam pushing is carried out according to the standard mode of 3+3, which is divided into a welding operation area and a group assembly and pushing operation area, 3 beam sections are welded and 3 beam sections are assembled and pushed each time, and according to the different lengths of the steel beam sections, 2-3 times of pushing are required to complete the single hole pushing;

[0020] S55, steel guide beam upper pier; the steel guide beam upper pier is quickly completed through "one drop, one lift and one forward", that is, the N+0# pier is lowered, the N+1# pier is jacked up, and the front end of the N+2# steel guide beam pier is higher than the temporary pier, and then the steel guide beam is pushed forward, so that the steel guide beam upper pier is completed;

[0021] S56, inter-lane steel beam pushing; the 5-hole water approach bridge is 1 lane, 40 cm expansion joints are arranged between the lanes, the original temporary connection of the steel beam is cancelled, the steel beam is directly welded with the steel beam, after the 5-10# pier steel beam is pushed to the design pier position, the 5# pier steel beam is cut, and then the 0-5# pier steel beam is continuously pushed forward to the design pier position, so that the erection of each lane is completed;

[0022] S57, steel beam falling; the steel beam falling is carried out in units of lanes, the linear of the whole lane steel beam is adjusted, the linear meets the requirements, the walking jack and the pier are withdrawn, the vertical jacks and the temporary steel plates are reinstalled, 2 450t vertical jacks are arranged at the intermediate pier, 4 450t vertical jacks are arranged at the transition pier, which are arranged at the lower damping cushion stone, and the temporary steel plates are arranged at the support; by alternately withdrawing the steel plates on the jacks and installing the temporary steel plates, the steel beam is lowered to the design elevation position.

[0023] As preferred, the specific steps of the bridge deck erection process in S6 are as follows:

[0024] S61, assembly of the erecting machine; the advantages of the lifting station are fully utilized, 3 pieces of bridge deck at each 10# pier are hoisted by the lifting station in priority, and then the bridge deck is used as the erecting machine assembly platform; at the same time, the scattered parts are locally assembled under the trestle, and then hoisted to the steel beam for overall assembly by the lifting station;

[0025] S62, Precast bridge deck transportation and erection construction: The bridge deck is transported to the lifting station via the main trestle by a deck transport vehicle. The lifting station lifts the bridge deck onto the rail transport vehicle, which then transports it to the erection machine. The rails are fixed to the bridge deck in the longitudinal direction of the bridge by rail clamps.

[0026] S63, precast bridge deck erection; after the steel channel beam is lowered, rubber strips are used to seal both sides of the joint surface between the bridge deck and the upper flange of the steel beam. After the rubber strips are installed, 20mm thick epoxy mortar is applied to the area around the rubber strips before feeding and lowering the deck.

[0027] As a preferred option, the specific steps of the bridge panel lamination process in S7 are as follows:

[0028] S71. After the bridge deck is erected, install the permanent supports on the top of the N+0# and N+5# piers of the side spans first;

[0029] S72. Before the steel beams are lifted, pour concrete for the reserved grooves of the three bridge decks near the 0.15L of the intermediate piers of the highway bridge deck, and strengthen curing. The reserved grooves of the transverse wet joints and small longitudinal beams will not be poured for the time being. Other bridge decks will not be combined with the steel channel beams before the steel beams are lifted. The lower track beam bridge decks will not be combined with the steel channel beams before the steel beams are lifted.

[0030] S73. Lift the steel beam at the top of pier N+2#. First, pour shrinkage-compensating concrete for all wet joints and reserved grooves in the L2 length range of the N+2# span and the L3 length range of the N+3# span. Then, pour shrinkage-compensating concrete for all wet joints and reserved grooves at the top of pier N+2#. When the strength of the cast-in-place concrete reaches more than 90% and the curing period is not less than 7 days, tension the cast-in-place concrete bridge deck in this area and the transverse prestressed steel strands passing through the reserved grooves of the precast bridge deck. Lower the beam section at the top of pier N+2# and place it on the support.

[0031] S74. Lift the steel beam at the top of pier N+3#. First, pour the shrinkage-compensating concrete for the wet joints and reserved grooves in the L4 length range of the N+4# span. Then, pour the shrinkage-compensating concrete for all wet joints and reserved grooves at the top of pier N+3#. When the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, tension the cast-in-place concrete bridge deck in this area and the transverse prestressed steel strands passing through the reserved grooves of the precast bridge deck. Lower the beam segment at the top of pier N+3# and place it on the support.

[0032] S75. Meanwhile, the N+1# and N+4# pier top steel beams are jacked up, compensation shrinkage concrete for wet joints and reserved slots in the N+1# hole midspan and L1 length range of the transition pier top, the N+5# hole midspan and L5 length range of the transition pier top is poured; then, compensation shrinkage concrete for all wet joints and reserved slots of the N+1# and N+4# pier tops is poured; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, the cast-in-place concrete bridge deck in the region and the transverse prestressed steel strand at the reserved slot of the precast bridge deck are tensioned; the N+1# and N+4# pier top beam segments are lowered and placed on the bearings.

[0033] As preferred, the specific steps of the "one lowering, one lifting and one advancing" mode are as follows: the steel guide beam is placed on the pier; first, the N+0# pier rear steel beam is lowered to the lowest, then the N+1# pier steel beam is jacked up, the N+1# pier temporary steel plate is raised until the steel guide beam is higher than the temporary pier of the N+2# pier, then it is pushed forward, and finally it is lowered on the N+2# pier walking top, that is, the steel guide beam is placed on the N+2# pier, and the pier placement is completed.

[0034] The technical effect of the present application mainly embodies that: the method proposed by the present application first adopts the bidirectional synchronous pushing construction technology to complete the steel slot beam erection, then uses the bridge deck panel laying machine to lay the precast bridge deck panel, and finally completes the superposition of the bridge deck panel and the steel beam by the top and drop beam in a unit, that is, the combined construction method of first pushing, then panel laying and then superposition. Compared with the conventional whole hole hoisting method described above, the method does not need to carry out a large amount of dredging, does not need to invest in a plurality of large-scale equipment for a long time, does not need to set a connecting plate on each pier top, only needs to invest in certain walking top equipment and panel laying machines, the process is more compact, the construction efficiency is improved, the advantages of the bidirectional synchronous pushing construction technology, the bridge deck panel laying machine erection technology and the top and drop beam superposition technology are fully utilized, and the construction period and economic benefits are obvious. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The process flow chart of the present application is a large-span precast erection steel-concrete composite beam construction method;

[0036] Figure 2 The state structure diagram of "one lowering, one lifting and one advancing";

[0037] Figure 3 The state structure diagram of the 5-hole bridge hole of the water approach bridge is 1 unit;

[0038] Figure 4 The layout diagram of the highway beam middle pier drop beam;

[0039] Figure 5 The layout diagram of the highway beam transition pier drop beam;

[0040] Figure 6 The combined schematic diagram of the bridge deck panel before the highway beam jacking up;

[0041] Figure 7 State structure diagram for bridge deck panel lamination process S73;

[0042] Figure 8 State structure diagram for bridge deck panel lamination process S74;

[0043] Figure 9 State structure diagram for bridge deck panel lamination process S75;

[0044] Figure 10 State structure diagram for north shore water approach bridge steel channel beam jacking construction step one;

[0045] Figure 11 State structure diagram for north shore water approach bridge steel channel beam jacking construction step two;

[0046] Figure 12 State structure diagram for north shore water approach bridge steel channel beam jacking construction step three;

[0047] Figure 13 State structure diagram for north shore water approach bridge steel channel beam jacking construction step four;

[0048] Figure 14 State structure diagram for north shore water approach bridge steel channel beam jacking construction step five;

[0049] Figure 15 State structure diagram for north shore water approach bridge steel channel beam jacking construction step six;

[0050] Figure 16 State structure diagram for north shore water approach bridge steel channel beam jacking construction step seven. DETAILED DESCRIPTION

[0051] The specific embodiments of the present application are described in further detail below with reference to the accompanying drawings, so that the technical scheme of the present application is easier to understand and master.

[0052] In the present embodiment, it is to be understood that the terms "intermediate", "upper", "lower", "top", "right side", "left end", "upper", "back", "middle", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0053] In addition, in the present specific embodiment, if the connection or fixing manner between components is not specifically described, the connection or fixing manner can be through bolt fixing or pin fixing commonly used in the prior art, or pin shaft connection, etc. Therefore, in the present embodiment, it is not described in detail.

[0054] Example one:

[0055] A large-span prefabricated erection steel-concrete composite beam construction method, comprising the following steps:

[0056] S1, construction of a ring-shaped trestle; the bridge is located in a shallow area of an inner bay, where the high and low tides are frequent. If the steel beam is transported by water, a large amount of dredging is required to open the transportation channel, and the economic cost of this method is relatively high. Therefore, the method of main trestle transportation is adopted. Because the construction front of the water approach bridge on the north shore is as long as 1396 m, in order to alleviate the overall traffic on site and reduce the influence of steel beam construction on other constructions, a water ring-shaped trestle is arranged at the 9#-11# piers.

[0057] S2, construction of a splicing support; the steel trough beam splicing support on the north shore is located at the 9#-11# piers, which serves as an operation platform for temporary storage, linear adjustment, welding, painting and jacking of the steel beam. The structure process of the splicing support is as follows: steel pipe piles are inserted and driven, pile-to-pile connecting systems are installed, pile top distribution beams are installed, longitudinal Bailey beams are installed, transverse distribution beams are installed, operation platforms, tracks, jacks and pads are installed. Each steel trough beam splicing support is composed of a highway steel trough beam splicing support and a track steel trough beam splicing support, pile-to-pile connecting systems are arranged between the steel pipe piles of each splicing support, and a consistent longitudinal slope is arranged on the top of the splicing support.

[0058] S3, construction of a lifting station; the lifting station and the overhead traveling crane form a gantry hoisting device, which is mainly used for hoisting of steel trough beams, frame plate components and prefabricated bridge deck slabs. The lifting station is located at the 10# pier and adopts a pipe pile + distribution beam structure. The overhead traveling crane girder is arranged transversely across the bridge, with a width of 52 m and a height of 43 m above the top surface of the pile cap. The lifting station can move 25 m along the longitudinal direction of the bridge, with a rated lifting capacity of 120 t. The longitudinal slope of the track should not be greater than 1%. The construction process of the lifting station is as follows: steel pipe piles are inserted and driven, pile-to-pile connecting systems are installed, pile top longitudinal and transverse distribution beams are installed, side walls are installed, transverse overhead traveling crane girders are installed, overhead traveling cranes are installed, and finally trial hoisting is performed.

[0059] S4, construction of a pier top bracket; the pier top bracket is a non-floor type truss support structure, with a triangular truss structure at the lower part and a longitudinal and transverse distribution beam + panel at the upper part. It is anchored and connected with the concrete pier body through pre-buried climbing cones. Except for the 10# pier in the middle, pier top brackets need to be installed on the top of other piers. The position of the pier top bracket is accurately set to ensure smooth jacking of the steel beam.

[0060] S5, steel trough beam jacking construction; the steel beam hoisting, linear adjustment, welding construction, painting construction, jacking construction and linear adjustment of the whole after jacking are sequentially and circularly performed for each steel beam segment. All steel beams are jacked to the designed pier position, and then the last three segments of steel trough beams are assembled in situ. Finally, the steel beams are lowered to the designed elevation in units of one span, and the erection of the steel beams of the whole bridge is completed.

[0061] S6, bridge deck slab erection;

[0062] S7, Bridge deck composite construction; The composite bridge deck is lifted and lowered by jacks arranged on the pier top. The steel beams are lifted to the design height by first lifting the middle pier and then the two sides. Then, the wet joints in the positive bending moment area at the mid-span of both sides and the wet joints in the negative bending moment area at the pier top are poured in sequence. After the wet joints are cured and tensioned, the composite beams are lowered to the design elevation, thus completing the system conversion between the steel channel beam and the composite beam.

[0063] S8 completes the conversion of the steel-concrete composite beam system.

[0064] Example 2:

[0065] The specific steps involved in the jacking construction of the S5 steel channel beam are as follows:

[0066] S51, Walking Gear Installation; The approach bridge in the water adopts a combined road and rail system, with multiple layers, including left and right road beams and rail beams. Two walking gears are installed on each side, and a total of six walking gears are required on each pier. The height and plan position of the walking gears should be installed according to the design requirements. The axis of the walking gears and the piers on both sides should be parallel to the design axis of the steel beams. The installation process of the walking gears is as follows: level the installation surface, install the walking gears and the upper distribution beams, install the piers on both sides and the upper distribution beams, and connect all pipelines.

[0067] S52, Steel guide beam installation; In order to reduce the length and deflection of the steel channel beam cantilever during the jacking process, and at the same time to guide the beam, a 50m long steel guide beam is set at the front end of the steel channel beam. It is a truss structure. The main trestle bridge and the ring trestle bridge are fully utilized. The sections are hoisted to the designated position by crawler crane for assembly.

[0068] S53, First span of steel channel beam jacking; The first span of steel beam jacking is strictly jacked according to the calculation steps, assembling the corresponding segments, and jacking the corresponding distance until the guide beam is on the pier;

[0069] S54, Non-first span steel beam jacking; Non-first span steel beam jacking is carried out according to the 3+3 standard jacking construction, which is divided into a welding operation area and an assembly jacking operation area. Each time, 3 beam segments are welded and 3 beam segments are assembled and jacked. Depending on the length of the steel beam segments, it takes 2-3 jacking operations to complete a single span jacking.

[0070] like Figure 2 As shown in Figure S55, the steel guide beam is placed on the pier. The steel guide beam can be placed on the pier quickly by "lowering, raising and advancing". That is, lowering the N+0# pier, raising the N+1# pier, so that the front end of the steel guide beam of the N+2# pier is higher than the temporary pier, and then pushing it forward to complete the placement of the guide beam. Figure 2 Taking Pier 13, Pier 14, and Pier 15 as examples.

[0071] like Figure 3As shown in Figure S56, the steel beams of the connecting sections are pushed up; the five spans of the approach bridge in the water are connected in one section, and a 40cm expansion joint is set between the sections. The original temporary connection of the steel beams is cancelled, and the steel beams are directly welded to each other. After the steel beams of piers 5-10 are pushed up to the designed pier position, the steel beam of pier 5 is cut open, and then the steel beams of piers 0-5 are pushed forward to the designed pier position. The erection of each section is completed in this way.

[0072] like Figures 4-5 As shown in Figure S57, the steel beam is lowered. The steel beam is lowered in units of a series. The alignment of the entire series of steel beams is adjusted. After the alignment meets the requirements, the stepping stones and piers are removed, and the vertical jacks and temporary steel plates are reinstalled. Two 450t vertical jacks are set on the intermediate piers, and four 450t vertical jacks are set on the transition piers. All of them are placed at the lower damping pads. The temporary steel plates are placed at the supports. The steel beam is lowered to the design elevation position by alternately removing the steel plates on the jacks and the installed temporary steel plates.

[0073] The specific steps of the "one-lower-one-up-one-forward" mode are as follows: Steel guide beam onto the pier; First, lower the steel beam behind pier N+0 to the lowest point, then lift the steel beam of pier N+1, raise the temporary steel plate of pier N+1 until the steel guide beam is higher than the temporary support of pier N+2, then push it forward, and finally place it on top of pier N+2, that is, the steel guide beam is on pier N+2, and the pier mounting is completed.

[0074] Taking the jacking construction of the steel channel beam of the approach bridge in the water on the north bank as an example

[0075] The steel-concrete composite beams for the approach bridge on the north bank have two sets of work lines, erected from pier 10 towards the main bridge / north bank. Each work line includes two work surfaces: one for the highway beam and one for the track beam. The construction steps on the north bank are briefly explained using the work line from pier 10 to pier 20 as an example:

[0076] like Figure 10 As shown, step one: Use a transport vehicle to transfer the guide beam segment from the material wharf of pier #22 to the bridge site of pier #10 via the main trestle bridge; use the lifting station to hoist the guide beam segment and slide it to the front end of the support through the top sliding track of the assembly support, at which point the front cantilever of the guide beam is 4m; adjust the plane position and ground elevation of the guide beam and weld the guide beam into a whole; after the guide beam is welded, use the walking jacking device on the assembly support to push the guide beam forward 10m, at which point the maximum cantilever of the guide beam is 14m.

[0077] like Figure 11As shown, step two: hoist and assemble the steel channel beam segments in the order of "track beam segment first → upstream highway beam segment → downstream side highway beam segment"; hoist the "first steel channel beam segment (pre-connected with the last guide beam segment in the factory)" onto the assembly support; adjust its plane position and beam bottom elevation according to the monitoring instructions; connect the first steel channel beam segment with the steel guide beam into a whole; push the guide beam and steel channel beam forward by 10m, at which point the maximum cantilever of the guide beam is 24m.

[0078] like Figure 12 As shown, step three: hoist the second and third steel channel beam segments in sequence; adjust their planar position and beam bottom elevation according to the monitoring instructions; weld them to the first steel channel beam segment to form a whole; push the guide beam and the steel channel beam forward as a whole by pushing forward 15m, at which point the maximum cantilever of the guide beam is 39m.

[0079] like Figure 13 As shown, step four: hoist the 4th, 5th and 6th steel channel beam segments in sequence; adjust their planar position and beam bottom elevation according to the monitoring instructions; weld them to the 3rd steel channel beam segment to form a whole; push the guide beam and steel channel beam forward 20m, at which point the maximum cantilever of the guide beam is 59m.

[0080] like Figure 14 As shown, step five: hoist the 7th and 8th steel channel beam segments in sequence; adjust their plane position and beam bottom elevation according to the monitoring instructions; weld them with the 6th segment to form a whole; push the guide beam and steel channel beam forward 11m as a whole, at which point the 11th pier on the guide beam is located.

[0081] like Figure 15 As shown, step six: push the guide beam and steel channel beam forward by 5 segments; hoist 6 segments of channel beam, and then carry out the channel beam jacking and erection in the "3+3" mode, that is, divide it into a welding operation area and an assembly and jacking operation area, welding 3 beam segments and assembling and jacking 3 beam segments each time.

[0082] like Figure 16 As shown, step seven: repeat step six until the bracket next to pier #20 on the guide beam; use a crawler crane to dismantle the guide beam segments in sections; after the guide beam is dismantled, push the steel channel beam to the design position; lower the steel channel beam in stages to the design elevation and support it on the permanent support; remove the walking jacking device on the pier top to complete the jacking of the steel channel beam on the north bank (pier #2 to pier #20).

[0083] The specific layout of the jacking system is shown in "Table 1 Layout of the jacking system for the approach bridge in the water on the north bank (measured from the direction of the north bank)" and "Table 2 Layout of the jacking system for the approach bridge in the water on the north bank (measured from the direction of the main bridge on the north bank)".

[0084] Table 1. Layout of the approach bridge jacking system on the north bank (based on the direction of the north bank)

[0085]

[0086] Table 2 Layout of the Approach Bridge Jacking System on the North Bank (based on the direction of the main bridge on the north bank)

[0087]

[0088] Example 3:

[0089] The specific steps of the S6 bridge deck erection process are as follows:

[0090] S61, panel erection machine assembly; give full play to the advantages of the lifting station, use the lifting station to prioritize hoisting 3 bridge panels of different sizes and lengths for pier #10, and then use the bridge panels as the assembly platform for the panel erection machine; at the same time, assemble a number of loose parts under the trestle bridge, and then hoist them to the steel beams for overall assembly through the lifting station.

[0091] S62, Precast bridge deck transportation and erection construction: The bridge deck is transported to the lifting station via the main trestle by a deck transport vehicle. The lifting station lifts the bridge deck onto the rail transport vehicle, which then transports it to the erection machine. The rails are fixed to the bridge deck in the longitudinal direction of the bridge by rail clamps.

[0092] S63, precast bridge deck erection; after the steel channel beam is lowered, rubber strips are used to seal both sides of the joint surface between the bridge deck and the upper flange of the steel beam. After the rubber strips are installed, 20mm thick epoxy mortar is applied to the area around the rubber strips before feeding and lowering the deck.

[0093] Example 4:

[0094] The bridge deck is stacked by jacks arranged on the pier tops to lift and lower the composite beam. The principle of lifting the composite beam at the pier tops is adopted. First, the composite beam is lifted to a specified height. Then, the wet joints in the positive bending moment area at the mid-span of both sides are poured first. Finally, the wet joints in the negative bending moment area at the pier tops are poured. After the wet joints are cured and tensioned, the composite beam is lowered to the design elevation, thus completing the system conversion between the steel channel beam and the composite beam.

[0095] The specific steps of the bridge panel lamination process in S7 are as follows:

[0096] S71. After the bridge deck is erected, install the permanent supports on the top of the N+0# and N+5# piers of the side spans first;

[0097] like Figure 6 As shown in Figure S72, before the steel beams are lifted, the concrete of the reserved grooves of the three bridge decks near the 0.15L of the intermediate piers is poured and cured. The concrete of the reserved grooves at the transverse wet joints and small longitudinal beams is not poured for the time being. Other bridge decks are not connected to the steel channel beams before the steel beams are lifted. The lower track beam bridge decks are not connected to the steel channel beams before the steel beams are lifted. Specifically, L is the span. The precast bridge decks are numbered A1a, A3, A5, A6, A8, A9a, and A11.

[0098] like Figure 7 As shown in Figure S73, lift the steel beam at the top of pier N+2#. First, pour the shrinkage-compensating concrete for all wet joints and reserved grooves in the L2 length range of the N+2# span and the L3 length range of the N+3# span. Then, pour the shrinkage-compensating concrete for all wet joints and reserved grooves at the top of pier N+2#. When the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, tension the cast-in-place concrete bridge deck in this area and the transverse prestressed steel strands passing through the reserved grooves of the precast bridge deck. Lower the beam segment at the top of pier N+2# and place it on the support.

[0099] like Figure 8 As shown in S74, lift the steel beam at the top of pier N+3#, first pour the shrinkage-compensating concrete for the wet joints and reserved grooves in the L4 length range of the N+4# span, then pour the shrinkage-compensating concrete for all wet joints and reserved grooves at the top of pier N+3#; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, tension the cast-in-place concrete bridge deck in this area and the transverse prestressed steel strands (only for highway beams) passing through the reserved grooves of the precast bridge deck; lower the beam segment at the top of pier N+3# and place it on the support;

[0100] like Figure 9 As shown in S75, simultaneously lift the steel beams at the top of piers N+1# and N+4#, and pour compensating shrinkage concrete for the wet joints and reserved grooves in the L1 length range of the mid-span of N+1# and the top of the transition pier, and in the L5 length range of the mid-span of N+5# and the top of the transition pier; then pour compensating shrinkage concrete for all wet joints and reserved grooves at the top of piers N+1# and N+4#; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, tension the cast-in-place concrete bridge deck in this area and the transverse prestressed steel strands (only for highway beams) passing through the reserved grooves of the precast bridge deck; lower the beam segments at the top of piers N+1# and N+4# and place them on the supports.

[0101] Construction Process Principle: Due to the bridge's location in the shallow waters of the estuary, large vessels cannot access the site, and the dredging work is extensive. For the steel-concrete composite continuous beam in the shallow waters, the steel channel beams are first pushed into place. After the steel channel beams are pushed into position, a precast bridge deck is erected onto the steel channel beams using a scaffolding machine. Finally, the bridge deck and steel channel beams are joined by jacking down the steel channel beams. The steel channel beams are manufactured in the factory, transported to the site by water, and then transported via the main trestle bridge to the lifting station for hoisting. The elevation, horizontal alignment, and segment spacing of each segment are accurately adjusted, and then the joints between the steel channel beam segments are welded. Finally, the steel channel beams are jacked up using the scaffolding and the stepping jacks placed on each pier. After each round of jacking, the next round of steel beams is assembled, and this process is repeated until all the steel channel beams are jacked up. The bridge deck is prefabricated in sections at the precast beam yard and transported to the erection machine for installation. During the installation of the bridge deck, rubber strips and epoxy mortar are first applied to the steel channel beams to ensure a tight and secure connection between the precast concrete bridge deck and the steel beam surface. When the bridge deck is stacked, the steel beams are lifted up using vertical jacks on the pier tops, then wet joints and shear grooves are poured, and transverse prestressed steel strands are tensioned. Finally, the composite beam is lowered to the design elevation, achieving the stacking of the bridge deck and the steel channel beam. This process, through the prefabrication, erection, and stacking of bridge deck sections, enables lightweight and rapid construction of steel-concrete composite continuous beams in shallow water areas.

[0102] The main technical advantages of this invention are as follows: The proposed method involves first erecting the steel channel beam using a bidirectional synchronous jacking construction technique, then laying the precast bridge deck panels using a bridge deck panel erection machine, and finally, completing the system conversion by jacking down the beams in units of one span. This is a combined construction method of jacking, then erecting panels, and finally stacking. Compared to the conventional whole-span hoisting method described above, this method eliminates the need for extensive dredging, long-term investment in multiple extra-large equipment, and the need for connecting plates on each pier top. It only requires a certain amount of jacking equipment and a panel erection machine. The process is more streamlined, construction efficiency is improved, and the advantages of bidirectional synchronous jacking construction, bridge deck panel erection machine technology, and jacking down beam stacking technology are fully utilized, resulting in significant improvements in construction time and economic benefits.

[0103] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A construction method of a long-span prefabricated erection steel-concrete composite beam, characterized by, Comprising the following steps: S1, construction of ring-shaped trestle; S2, construction of assembling support; the assembling support of steel trough girder on the north bank is located at 9#-11# pier and serves as the operation platform for temporary storage of steel girder, linear adjustment, welding, painting and jacking; the structure process of assembling support is as follows: steel pipe pile is inserted and driven, pile-to-pile connecting system is installed, pile top distribution beam is installed, longitudinal bridge direction Bailey beam is installed, transverse distribution beam is installed, operation platform, track, jack, cushion block are installed, each steel trough girder assembling support is composed of highway steel trough girder assembling support and track steel trough girder assembling support, pile-to-pile connecting system is arranged between steel pipe piles of each assembling support, and the same longitudinal slope as steel girder is arranged on the top of assembling support; S3, construction of lifting station; the lifting station and the crown block form a gantry hoisting equipment and is mainly used for hoisting of steel trough girder, frame plate mechanism and precast bridge deck; the lifting station is located at 10# pier and adopts the structure of pipe pile superimposed distribution beam, the crown block beam is arranged in the transverse direction of bridge, the width is 52m, the height above the top surface of pile cap is 43m, the lifting station can move 25m in the longitudinal direction of bridge, the rated lifting weight is 120t, the track longitudinal slope should not be greater than 1%, and the construction process of lifting station is as follows: steel pipe pile is inserted and driven, pile-to-pile connecting system is installed, longitudinal and transverse distribution beams on the top of pile are installed, attached wall is installed, transverse crown block beam is installed, crown block is installed, and finally, trial lifting is carried out; S4, construction of pier top bracket; the pier top bracket is a non-floor type truss support structure, the lower part is a triangular truss structure, the upper part is longitudinal and transverse distribution beam+panel, the bracket is anchored and connected with the concrete pier body through pre-buried climbing cone, the pier top bracket needs to be installed on the top of each pier except 10# pier in the middle; S5, steel trough girder jacking construction; the steel girder hoisting, linear adjustment, welding construction, painting construction, jacking construction and linear adjustment of the whole after jacking are circularly carried out for each steel girder segment in turn, all steel girders are jacked to the design pier position, then the last 3 segments of steel trough girder are assembled in situ, finally, the steel girders are lowered to the design elevation in a unit of one span, and the steel girder erection of the whole bridge is completed; S6, bridge deck erection; S7, bridge deck superposition construction; the bridge deck superposition is realized by the jacks arranged on the top of pier, the principle of jacking the steel girders to the design height in turn from the middle pier to the two sides is adopted, then the wet joints in the central positive bending moment area of the two side spans and the wet joints in the negative bending moment area of the top of pier are poured in turn, after the wet joints are cured and tensioned, the composite girder is lowered to the design elevation, and the system conversion of steel trough girder and composite girder is completed; S8, completion of steel-concrete composite girder system conversion; S5 steel trough girder jacking construction Comprising the following steps: S51, installation of walking top; the whole approach bridge in water adopts the form of common rail collinear and layered combined construction, including left and right width highway beam and track beam, 2 walking tops are arranged in a single width, 6 walking tops are arranged in a single pier, the height and plane position of walking top should be installed according to the design requirements, the axis of walking top and the two side resting piers should be parallel to the design axis of steel girder, the installation process of walking top is as follows: the surface is leveled, walking top and the upper distribution beam are installed, the two side resting piers and the upper distribution beam are installed, and all pipelines are connected. S52, steel guide beam installation; to reduce the length and deflection of the steel trough beam cantilever during the pushing process, and to guide the beam body, a 50m long steel guide beam is set at the front end of the steel trough beam, which is a truss structure, fully utilizing the main trestle and ring trestle, and is hoisted to the designated position by the crawler crane in sections for assembly; S53, first hole steel trough beam pushing; the steel beam first hole pushing strictly follows the calculation steps, assembles the corresponding sections, and pushes the corresponding distance until the guide beam pier; S54, non-first hole steel beam pushing; the non-first hole steel beam pushing is carried out according to the standard mode of 3+3, which is divided into welding operation area and assembly pushing operation area, 3 beam sections are welded and 3 beam sections are assembled and pushed each time, according to the different lengths of the steel beam sections, the single hole pushing needs to be pushed 2-3 times; S55, steel guide beam pier; the steel guide beam pier is quickly completed through "one drop, one lift and one forward", that is, the N+0# pier is lowered, the N+1# pier is jacked up, and the front end of the N+2# steel guide beam pier is higher than the temporary pier, and then the steel guide beam is pushed forward, thereby completing the pier of the guide beam; S56, inter-lane steel beam pushing; the 5-hole bridge hole of the water approach bridge is 1 lane, 40cm expansion joints are set between the lanes, the original temporary connection of the steel beam is cancelled, the steel beam is directly welded with the steel beam, after the 5-10# pier steel beam is pushed to the designed pier position, the 5# pier steel beam is cut, and then the 0-5# pier steel beam is continuously pushed forward to the designed pier position, thereby completing the erection of each lane by this method; S57, steel beam landing; the steel beam landing is carried out in units of lanes, the linear of the whole lane steel beam is adjusted, the linear meets the requirements, the walking top and the pier are removed, the vertical jacks and the temporary steel plates are reinstalled; 2 450t vertical jacks are arranged at the intermediate pier, 4 450t vertical jacks are arranged at the transition pier, which are arranged at the lower damping cushion stone, and the temporary steel plates are arranged at the support; by alternately pulling out the steel plates on the jacks and installing the temporary steel plates, the steel beam is lowered to the designed elevation position.

2. The construction method of a long-span precast erection steel-concrete composite beam according to claim 1, characterized in that, The specific steps of the bridge deck panel erection process in S6 are as follows: S61, panel erector assembly; make full use of the advantages of the lifting station, use the lifting station to hoist 3 pieces of bridge deck panel at each 10# pier, then use the bridge deck panel as the panel erector assembly platform; at the same time, the local assembly of the panel erector is carried out under the trestle, and then the whole assembly is carried out on the steel beam through the lifting station; S62, precast bridge deck panel transportation and erection construction; the bridge deck panel is transported to the lifting station through the main trestle by the panel transport vehicle, lifted to the track panel transport vehicle by the lifting station, transported to the panel erector by the panel transport vehicle, and the steel rail is fixed on the bridge deck panel through the track clamp plate in the longitudinal bridge direction; S63, precast bridge deck panel erection; after the steel trough beam landing is completed, the rubber strip is sealed on both sides of the bridge deck panel and the steel beam flange joint surface, the 20mm thick epoxy mortar is applied in the area around the rubber strip after the installation of the rubber strip, and then the feeding and landing are carried out.

3. The construction method of long-span precast erection steel-concrete composite beam according to claim 1, characterized in that, The specific steps of the bridge deck panel stacking process in S7 are as follows: S71. After the bridge deck panel erection is completed, the N+0# and N+5# pier top permanent support of the side span is installed first; S72. Pour all the reserved slot concrete of three bridge deck panels near 0.15L of the intermediate pier before the steel beam jacking, L is the span, and strengthen the maintenance, the reserved slot concrete of the transverse wet joint and the small longitudinal beam is not poured, other bridge deck panels are not combined with the steel slot beam before the steel beam jacking, and the lower track beam bridge deck panel is not combined with the steel slot beam before the steel beam jacking; S73. Jack up the N+2# pier top steel beam, first pour the compensation shrinkage concrete of all wet joints and reserved slots in the L2 length range of the N+2# hole span and the L3 length range of the N+3# hole span, then pour the compensation shrinkage concrete of all wet joints and reserved slots of the N+2# pier top; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, the transverse prestressed steel bundle of the cast-in-place concrete bridge deck panel and the reserved slot of the precast bridge deck panel is tensioned; the N+2# pier top beam segment is lowered and placed on the support; S74. Jack up the N+3# pier top steel beam, first pour the compensation shrinkage concrete of the wet joint and the reserved slot in the L4 length range of the N+4# hole span, then pour the compensation shrinkage concrete of all wet joints and reserved slots of the N+3# pier top; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, the transverse prestressed steel bundle of the cast-in-place concrete bridge deck panel and the reserved slot of the precast bridge deck panel is tensioned; the N+3# pier top beam segment is lowered and placed on the support; S75. Jack up the N+1# and N+4# pier top steel beams at the same time, pour the compensation shrinkage concrete of the wet joint and the reserved slot in the L1 length range of the N+1# hole span and the transition pier top and the L5 length range of the N+5# hole span and the transition pier top; then pour the compensation shrinkage concrete of all wet joints and reserved slots of the N+1# and N+4# pier top; when the strength of the cast-in-place concrete reaches more than 90% and the age is not less than 7 days, the transverse prestressed steel bundle of the cast-in-place concrete bridge deck panel and the reserved slot of the precast bridge deck panel is tensioned; the N+1# and N+4# pier top beam segments are lowered and placed on the support.

4. The construction method of long-span precast erection steel-concrete composite beam according to claim 1, characterized in that, The specific steps of the "one down, one up, and one forward" mode are as follows: the steel guide beam is on the pier; first, the N+0# pier rear steel beam is lowered to the lowest, then the N+1# pier steel beam is jacked up, the N+1# pier temporary steel plate is lifted, until the steel guide beam is higher than the temporary pier of the N+2# pier, then it is pushed forward, and finally it falls on the N+2# pier step top, that is, the steel guide beam climbs on the N+2# pier, and the on-pier is completed.

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