Composite beam construction method ignoring standard segment wet joint equal time

Abstract

The present application relates to a kind of ignore standard segment wet joint equal time superposed beam construction method, belong to bridge construction technical field.Wet joint of pouring bridge deck slab is poured in even section, for i≤N-1 Even section, the pouring process of the wet joint corresponding to the i th main beam section is carried out after the crane corresponding to the i+1 th main beam section moves forward procedure;Wherein, N is the total number of main beam section, the present application is by the method of carrying out subarea pouring bridge deck slab wet joint in even section and bridge tower inner cable anchorage zone hydraulic device cooperation, reach the effect of significantly shorten construction period, and while facilitating the construction of site, can reduce the tensile stress of bridge deck slab at cable anchorage position to avoid the cracking of bridge deck slab, solve the problem that the existing steel-mix superposed beam cable-stayed bridge cannot shorten construction time under the premise of guaranteeing bridge structure safety.

Description

A construction method for composite beams that ignores the equal strength time of wet joints in standard segments Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically relating to a method for constructing composite beams that ignores the equal strength time of wet joints in standard segments. Background Technology

[0002] In engineering construction, steel-concrete composite beams fully utilize the compressive properties of concrete and the tensile properties of steel through shear studs and wet joints. Compared with concrete beam structures, steel-concrete composite beams have advantages such as low cost, convenient construction, high span, and good durability.

[0003] In steel-concrete composite cable-stayed bridges, the steel beams are installed and connected in segments, and the concrete bridge decks are prefabricated in sections. After being laid on the steel beams, wet joint concrete is poured between adjacent bridge decks, and the stay cables are installed and tensioned. According to the timing of the wet joint pouring of the bridge deck, the common construction methods for the superstructure of existing large-span composite cable-stayed bridges are: (1) After each steel beam segment is installed, the bridge deck on that segment is laid, wet joint concrete is poured and allowed to strengthen; (2) After all steel beam segments are installed, the wet joints of the bridge decks on the steel beams are poured and allowed to strengthen at the same time, and the stay cables are installed and tensioned in sequence from the direction of the adjacent tower to the direction away from the tower according to the cable number.

[0004] The above methods (1) require waiting for the concrete of the wet joint to reach the design strength segment by segment, which consumes a lot of time and cost; methods (2) are prone to cracking of the bridge deck and wet joint on the front steel beam segment. Moreover, the construction cycle of the above two construction methods is relatively long, the on-site construction is inconvenient, and it is not conducive to the control of structural alignment and stress. At the same time, after summarizing and analyzing many years of engineering practice, it was found that the timing and location of the wet joint pouring of the steel-concrete composite beam cable-stayed bridge, as well as the timing of the cable tensioning, have a great influence on the stress state of the structure.

[0005] Therefore, optimizing the construction process is necessary to address the issue of steel beam stress reaching critical limits, ensuring the safety of the bridge structure. At the same time, shortening the construction time has become an urgent problem for those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a composite beam construction method that ignores the equal strength time of wet joints in standard segments, thus solving the problem of shortening the construction time of existing steel-concrete composite beam cable-stayed bridges while ensuring the structural safety of the bridge.

[0007] The objective of this invention can be achieved through the following technical solution: a composite beam construction method that ignores the equal strength time of wet joints in standard segments, wherein the wet joints of the bridge deck are poured in even-numbered segments, and for even-numbered segments i≤N-1, the pouring process of the wet joint corresponding to the i-th main beam segment is carried out after the crane forward movement process corresponding to the i+1-th main beam segment.

[0008] For i = N (N is an even number), the pouring process of the wet joint of the bridge deck of the entire segment corresponding to the i-th main beam segment, the pouring process of the wet joint of the bridge deck of the entire segment corresponding to the i-1-th main beam segment, and the pouring process of the wet joint of the bridge deck of the main longitudinal beam area corresponding to the i-2-th main beam segment are carried out simultaneously.

[0009] For i = N (N is an odd number), the pouring process of the wet joint of the bridge deck of the entire segment corresponding to the i-th main beam segment is carried out simultaneously with the pouring process of the wet joint of the bridge deck of the main longitudinal beam area corresponding to the (i-1)-th main beam segment.

[0010] N represents the total number of main beam segments.

[0011] As a preferred technical solution of the present invention, for even-numbered segments i≤N-2, the second cable tensioning process corresponding to the i-th main beam segment is carried out after the bridge deck hoisting process corresponding to the i+1-th main beam segment;

[0012] For odd-numbered segments with i ≤ N-2, the second cable tensioning operation corresponding to the i-th main beam segment is performed after the crane forward movement operation corresponding to the (i+1)-th main beam segment;

[0013] The second cable-stayed connection process for the cables corresponding to the last two main girder segments is carried out after all the wet joints of the bridge deck have been poured.

[0014] As a preferred technical solution of the present invention, the main longitudinal beams corresponding to each main beam segment can all be box-shaped or I-shaped cross-sections, and the segments can be connected by welding or bolting.

[0015] As a preferred technical solution of the present invention, in the first cable tensioning process corresponding to each main beam segment, the internal force value of the tensioned cable is controlled to a preset value, and in the second cable tensioning process corresponding to each main beam segment, the anchor head pull-out amount of the tensioned cable is controlled to a preset value. The two tensioning processes are coordinated with the segment elevation as auxiliary control.

[0016] As a preferred technical solution of the present invention, after the wet joint pouring process of the even-numbered construction segments, the cyclic construction of the next segment can begin.

[0017] As a preferred technical solution of the present invention, the first and second tensioning of each cable are performed by two different hydraulic devices, and the two hydraulic devices move upward alternately.

[0018] As a preferred technical solution of the present invention, there are multiple parallel constructions. When constructing an even number of segments, the corresponding bridge deck crane is moved forward to the construction segment and the second cable of the previous segment is constructed in parallel. The second cable is completed before the bridge deck crane is moved forward to the position. After the bridge deck is hoisted, the steel bars at the wet joint of the bridge deck can be tied and completed before the wet joint is poured.

[0019] When constructing odd-numbered segments, the second cable laying of the previous segment, the binding of the steel reinforcement at the wet joint of the bridge deck, and the hydraulic equipment moving up two segments can be carried out simultaneously with the hoisting and welding of the main steel beam when the bridge deck crane moves forward to the current segment. All three processes are completed before the installation of the crossbeams and small longitudinal beams.

[0020] As a preferred embodiment of the present invention, the second cable-stayed connection process for the last two main beam segments is carried out after all the wet joints of the bridge deck have been poured.

[0021] As a preferred technical solution of the present invention, the alignment of the completed segment is fine-tuned by using the second cable lag of one segment.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The method of pouring wet joints of bridge deck in even-numbered segments in combination with the hydraulic device in the anchorage area of ​​the cable in the bridge tower can significantly shorten the construction period. While facilitating on-site construction, it can also reduce the tensile stress of the bridge deck at the cable anchorage location, thereby avoiding cracking of the bridge deck.

[0024] 2. Multiple construction processes are carried out simultaneously, further shortening the construction period;

[0025] 3. During the construction of even-numbered segments, the wet joint of the anchorage point of the stay cable on the main longitudinal beam of this segment was not poured. During the construction of subsequent segments, the influence of excessive stress in the wet joint of the bridge deck can be eliminated. Therefore, after the wet joint process of even-numbered segments is completed, the hoisting and welding process of the main longitudinal beam of the next segment can be carried out directly.

[0026] 4. The second cable of the stay cable is delayed by one segment. By controlling the pull-out amount of the stay cable anchor head and the elevation of the bridge deck segment, the internal force of the cable can be accurately controlled, and the alignment of the bridge can also be well controlled. Attached Figure Description

[0027] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0028] Figure 1 is a construction flowchart of the present invention at the last standard segment;

[0029] Figure 2 is a schematic diagram of the cross-sectional structure of the main longitudinal beam of the present invention;

[0030] Figure 3 is a schematic diagram of the hoisting of the n-1 segment main longitudinal beam of the present invention;

[0031] Figure 4 is a schematic diagram of the hoisting of the n-1 segment crossbeam and small longitudinal beam of the present invention;

[0032] Figure 5 is a schematic diagram of the first cable tensioning of segment n-1 of the present invention;

[0033] Figure 6 is a schematic diagram of the hoisting of the n-1 segment bridge deck of the present invention;

[0034] Figure 7 is a schematic diagram of the bridge deck crane of the present invention moving forward to segment n-1;

[0035] Figure 8 is a schematic diagram of two cable-stayed cables of segment n-2 of the present invention;

[0036] Figure 9 is a schematic diagram of the hoisting of the n-segment main longitudinal beam according to the present invention;

[0037] Figure 10 is a schematic diagram of the hoisting of the n-segment crossbeam and small longitudinal beam of the present invention;

[0038] Figure 11 is a schematic diagram of the first cable tensioning of the n-segment according to the present invention;

[0039] Figure 12 is a schematic diagram of the hoisting of n-segment bridge deck panels according to the present invention;

[0040] Figure 13 is a schematic diagram of the bridge deck crane of the present invention moving forward to segment n;

[0041] Figure 14 is a schematic diagram of two cable-stayed cables of segment n-1 of the present invention;

[0042] Figure 15 is a schematic diagram of the wet joint casting of the three segments of the present invention;

[0043] Explanation of main component symbols

[0044] In the diagram: 1. Main longitudinal beam; 2. Cross beam; 3. Secondary longitudinal beam; 4. Bridge deck; 5. First cable; 6. Wet joint; 7. Crane; 8. Second cable. Detailed Implementation

[0045] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0046] Please refer to Figure 1-15. This embodiment provides a composite beam construction method that ignores the equal strength time of wet joints in standard segments. The wet joints 6 of the bridge deck 4 are poured in even-numbered segments. For even-numbered segments i≤N-1, the pouring process of the wet joint 6 corresponding to the i-th main beam segment is carried out after the crane 7 moving forward process corresponding to the i+1-th main beam segment.

[0047] For i = N (N is an even number), the pouring process of the wet joint 6 of the bridge deck 4 of the entire segment corresponding to the i-th main beam segment, the pouring process of the wet joint 6 of the bridge deck 4 of the entire segment corresponding to the i-1-th main beam segment, and the pouring process of the wet joint 6 of the bridge deck 4 of the main longitudinal beam 1 area corresponding to the i-2-th main beam segment are carried out simultaneously.

[0048] For i = N (N is an odd number), the pouring process of the wet joint 6 of the bridge deck 4 of the entire segment corresponding to the i-th main beam segment is carried out simultaneously with the pouring process of the wet joint 6 of the bridge deck 4 of the main longitudinal beam 1 area corresponding to the (i-1)-th main beam segment.

[0049] N represents the total number of main beam segments.

[0050] The construction of a steel-concrete composite cable-stayed bridge generally includes the following steps: hoisting of the side main beams → hoisting of the crossbeams 2 → hoisting of the small longitudinal beams 3 and the stabilizer plate → installation of one cable stay → installation of the bridge deck 4 → forward movement of the full-rotation crane 7 → pouring of the wet joint 6 and tensioning of the transverse prestressing of the previous segment → tensioning of the second cable stay → cycle to the next segment. During this process, the closure time and temperature have a significant impact on key closure parameters such as the closure joint width, the elevation of the two side main beams, the offset, and the mileage. Therefore, determining the specific closure time and temperature in advance is fundamental to the closure construction. To minimize the impact of temperature, and given that temperature fluctuations are generally smaller at night, closure is usually carried out at night. Closure refers to connecting two or more independently constructed beam segments (also called beam pieces) together to form a complete beam structure. In the above steps, the wet joint 6 pouring is the construction step for this connection. Therefore, wet joint 6 pouring is usually carried out at night. For safety reasons, the hoisting work of the next segment's main longitudinal beam 1 is not performed at night. Performing the preliminary work for wet joint 6 on only the same segment does not require a whole day. Therefore, the normal construction process takes a long time. Furthermore, after wet joint 6 pouring, a second set of cables 8 is needed to adjust the beam's horizontal and vertical directions to achieve the design requirements. After waiting overnight, wet joint 6 has already gained a certain strength, meaning the position of the previous beam segment is basically complete, and further adjustments are unlikely. Therefore, this construction method is not conducive to controlling the bridge structure's alignment and stress.

[0051] This application, by performing wet joint pouring only on the preceding segments in even-numbered stages, can not only shorten the construction time but also better control the bridge structure alignment and stress.

[0052] In order to better control the bridge structure alignment and stress, in this embodiment, for even-numbered segments i≤N-2, the second tensioning process of cable 8 corresponding to the i-th main beam segment is carried out after the bridge deck 4 hoisting process corresponding to the i+1-th main beam segment.

[0053] For odd-numbered segments i≤N-2, the second tensioning operation of cable 8 corresponding to the i-th main beam segment is carried out after the crane 7 forward movement operation corresponding to the (i+1)-th main beam segment;

[0054] The second cable-stayed section 8 for the cables corresponding to the last two main beam segments is carried out after all the wet joints 6 of the bridge deck 4 are poured.

[0055] Therefore, in this application, the wet joint 6 is poured only in even-numbered segments. After the second cable tensioning process in even-numbered segments, the wet joint 6, having gained sufficient strength overnight, is tensioned again after all structural components of the subsequent process are assembled. This allows for better control of the bridge's alignment and stress, as the wet joint 6 is not yet fully solidified and can still be adjusted. Furthermore, the second cable tensioning process in even-numbered segments is carried out after the bridge deck 4 hoisting process in odd-numbered segments, while the odd-numbered segments... Since the wet joint 6 will not be poured, the second cable tensioning process for even-numbered segments is carried out after the bridge deck 4 hoisting process corresponding to the (i+1)th main beam segment, which allows for better control of the bridge's structural alignment and stress. Similarly, the second cable tensioning process for odd-numbered segments is carried out after the crane 7 forward movement process corresponding to the (i+1)th main beam segment, that is, before the wet joint 6 is poured for even-numbered segments, thus controlling the bridge's structural alignment and stress. This is because the wet joint 6 is not poured for odd-numbered segments, and the pouring of the wet joint 6 for even-numbered segments ensures the structural alignment and stress of the odd-numbered segments.

[0056] In order to effectively resist positive and negative bending moments and meet the reinforcement requirements, in one embodiment, the main longitudinal beams 1 corresponding to each main beam segment can be box-shaped or I-shaped sections. The segments can be connected by welding or high-strength bolts. When the bridge span is large, the box beam is the best structural form. Its closed thin-walled section has a large torsional stiffness, which is especially advantageous for curved bridges and bridges constructed using cantilever construction. Moreover, the main longitudinal beam 1 with box section has good dynamic characteristics and small shrinkage deformation value.

[0057] To ensure a reasonable distribution of stress on the beam, in one embodiment, during the first cable tensioning step (step 5) for each main beam segment, the internal force of the tensioned cable is controlled to a preset value. During the second cable tensioning step (step 8) for each main beam segment, the anchor pull-out amount of the tensioned cable is controlled to a preset value. The two tensioning steps, combined with the segment elevation, serve as auxiliary controls. The preset value is first used to control the second cable tensioning step (step 8), and then the segment elevation is used for further control. This ensures that the geometry and structural stability of the beam meet the design requirements, while avoiding excessive stress on some cable stays, thereby improving the overall stress balance and stability of the beam.

[0058] To further shorten construction time, in one embodiment, after the wet joint 6 pouring process of the even-numbered construction segments, the next segment can be started in a cyclical construction. This process can be repeated to reduce construction time and improve construction efficiency.

[0059] To reduce the time spent on each cable pulling operation, in one embodiment, the first cable pulling 5 and the second cable pulling 8 of each cable are performed by two different hydraulic devices, and the two hydraulic devices move upward alternately. By having the two hydraulic devices move upward alternately, one hydraulic device can move to the position of the next cable pulling while the other device is performing cable pulling, thereby reducing the time required for cable pulling and improving construction efficiency.

[0060] To improve construction efficiency and reduce construction time, in one embodiment, multiple parallel constructions are carried out. When constructing even-numbered segments, the corresponding bridge deck crane 7 is moved forward to the construction segment and constructed in parallel with the second cable 8 of the previous segment. The second cable 8 is completed before the bridge deck crane 7 is moved forward to its position. After hoisting the bridge deck 4, the reinforcing bars at the wet joint 6 of the bridge deck 4 can be tied and completed before pouring the wet joint 6.

[0061] For construction of odd-numbered segments, when the bridge deck crane 7 moves forward to the current segment, the second cable 8 of the previous segment, the reinforcement at the wet joint 6 of the bridge deck 4, and the hydraulic equipment moving up two segments can be carried out simultaneously with the hoisting and welding of the main steel beam. These three processes are completed before the installation of the crossbeam 2 and the small longitudinal beam 3. This parallel construction of multiple processes greatly improves construction efficiency and reduces construction time, from the original 10-day construction cycle for each segment. By adopting the dual-stage cyclic method described in this invention, the wet joint 6 is poured once for two segments without the need for equal strength. Since the wet joint 6 is usually poured at night, but the hoisting of the next segment's main longitudinal beam 1 is not carried out at night for safety reasons, the wet joint 6 effectively achieves equal strength overnight. Combined with the alternating tensioning of the hydraulic system and the parallel construction of multiple processes, the average construction cycle for each segment is shortened to 5 days, effectively solving the problem of tight on-site construction schedules. Furthermore, after adopting the method of this invention, no adverse situations such as cracking of the bridge deck 44 or excessive stress in the steel beam occurred during on-site construction, thus ensuring the safe construction of the structure.

[0062] To ensure the stability and safety of the cable prestressing, in one embodiment, the second cable-stayed section 8 for the last two main girder segments is performed after the wet joints 6 of all bridge deck 4 have been poured. During the pouring of the wet joints 6, factors such as concrete shrinkage and temperature changes may cause deformation and stress concentration in the bridge deck 4. If the second cable-stayed section 8 is performed at this time, it may cause uneven stress distribution. After all the wet joints 6 of the bridge deck 4 have been poured, the concrete forms an integrated structure on the entire bridge deck 4 with a relatively stable stress distribution. Performing the second cable-stayed section 8 at this time can better control the tension of the cables, allowing it to be evenly transmitted to the main girder segments, thereby ensuring the stability and safety of the entire bridge structure.

[0063] To enable fine-tuning of the bridge alignment and ensure it meets design standards, in one embodiment, the alignment of the completed segments is fine-tuned by delaying the second cable 8 by one segment. This delay is performed after the bridge structure is essentially fixed and the load has been applied. At this stage, the prestress of the cables can be appropriately increased or decreased as needed, thereby fine-tuning the alignment of the completed segments. By adjusting the prestress, the deformation and deviation of the segments can be changed, ensuring the overall bridge alignment meets design requirements.

[0064] Taking the main girder segment of the intermediate standard section as an example, the two-stage cyclic construction method for steel-concrete composite cable-stayed bridges includes the following steps:

[0065] Step 1: Hoist the main longitudinal beam 1 corresponding to the (n-1)th main beam segment, as shown in Figure 3. The cross-section of the main longitudinal beam 1 can be a box-shaped or I-shaped section, as shown in Figure 2.

[0066] Step 2: Hoist the crossbeam 2 and the small longitudinal beam 3 corresponding to the (n-1)th main beam segment, as shown in Figure 4.

[0067] Step 3: The first tensioning of the cable is performed on the cable corresponding to the (n-1)th segment of the main beam. The initial tensioning of the cable is controlled by the internal force value of the cable, and the actual measured elevation of the main longitudinal beam 1 after each tensioning is used as the auxiliary control. At this time, the initial tensioning of the cable is completed under the first set of hydraulic equipment in the main tower. The cable after the initial tensioning is shown in Figure 5.

[0068] Step 4: Hoist the bridge deck 4 corresponding to the (n-1)th main beam segment, as shown in Figure 6.

[0069] Step 5: The bridge deck crane 7 is moved to segment n-1, as shown in Figure 7.

[0070] Step 6: The n-2 segment of the stay cable is pulled a second time, as shown in Figure 8. The amount of cable anchor head pull-out is used as the control for the two sections.

[0071] Step 7: Hoist the nth segment of the main longitudinal beam 1, as shown in Figure 8.

[0072] Step 8: Hoist the crossbeam 2 and small longitudinal beam 3 corresponding to the nth segment, as shown in Figure 10; Steps 6 and 7 can be carried out simultaneously after Step 5, and the construction is completed before the crossbeam 2 and small longitudinal beam 3 are bolted together in Step 8. During this period, the binding of the reinforcing bars at the wet joint 6 of the n-1th segment is also completed simultaneously, and the second set of hydraulic equipment moves two segments up to the nth segment inside the main tower column, waiting for the initial tensioning of the cable stays of the nth segment.

[0073] Step 9: Tension the cable corresponding to the nth segment of the main beam for the first time. The initial tensioning of the cable is controlled by the internal force value of the cable, and the actual measured elevation of the main longitudinal beam 1 after each tensioning is used as the auxiliary control. At this time, the initial tensioning of the cable is completed under the second set of hydraulic equipment in the main tower. The cable after the initial tensioning is shown in Figure 11.

[0074] Step 10: Hoist the bridge deck 4 corresponding to the nth main beam segment, as shown in Figure 12.

[0075] Step 11, the n-2 segment of the stay cable is tensioned a second time, as shown in Figure 13. The amount of cable anchor head pull-out is used as the control for the second tension.

[0076] Step 12: The bridge deck crane 7 moves forward onto segment n, as shown in Figure 14. Steps 11 and 12 can be carried out simultaneously after step 10, but step 11 must be completed before step 12 is completed. During this time period, the binding of the reinforcing bars at the wet joint 6 of segment n bridge deck 4 can also be carried out at the same time, but it must be completed before step 13.

[0077] Step 13: Pour the concrete in the wet joint area of ​​the three bridge deck segments 4 in the even-numbered segments, as shown in Figure 15.

[0078] For the last standard segment N being an even number of segments, the pouring process of the bridge deck 4 wet joint 6 for the entire segment corresponding to the Nth and N-1th main beam segments, as well as the pouring process of the bridge deck 4 wet joint 6 for the area of ​​the main longitudinal beam 1 corresponding to the N-2th main beam segment, are carried out simultaneously; for the last standard segment N being an odd number of segments, the pouring process of the bridge deck 4 wet joint 6 for the entire segment corresponding to the Nth main beam segment, as well as the pouring process of the bridge deck 4 wet joint 6 for the area of ​​the main longitudinal beam 1 corresponding to the N-1th main beam segment, are carried out simultaneously.

[0079] Because the second cable tensioning was delayed by one segment, the first main beam segment did not have a second cable tensioning process during construction. Furthermore, the second cable tensioning process for the last two main beam segments was carried out after all the bridge deck wet joints 6 were poured.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A construction method for composite beams that ignores the equal strength time of wet joints in standard segments, characterized in that: The pouring of wet joints in the bridge deck is carried out on even-numbered segments. For even-numbered segments i ≤ N-1, the pouring process for the wet joint corresponding to the i-th main girder segment is carried out after the crane forward movement process corresponding to the (i+1)-th main girder segment. For i = N (N is an even number), the pouring process for the wet joints of the bridge deck of the entire segment corresponding to the i-th main girder segment, the wet joints of the bridge deck of the entire segment corresponding to the (i-1)-th main girder segment, and the wet joints of the bridge deck in the main longitudinal beam area corresponding to the (i-2)-th main girder segment are all carried out separately. The construction processes are carried out simultaneously; for i=N (N is an odd number), the pouring process of the wet joint of the bridge deck for the entire segment corresponding to the i-th main girder segment is carried out simultaneously with the pouring process of the wet joint of the bridge deck for the main longitudinal beam area corresponding to the (i-1)-th main girder segment; where N is the total number of main girder segments; for even-numbered segments i≤N-2, the second cable tensioning process corresponding to the i-th main girder segment is carried out after the bridge deck hoisting process corresponding to the (i+1)-th main girder segment; for odd-numbered segments i≤N-2, The second cable tensioning process for the i-th main girder segment is carried out after the crane forward movement process for the (i+1)-th main girder segment. For the last two main girder segments, the second cable tensioning process is carried out after all bridge deck wet joints are poured. The first and second cable tensioning of each cable is performed using two different hydraulic devices, which alternately move upwards. Multiple parallel construction operations exist. For even-numbered segments, the corresponding bridge deck crane moves forward to the construction segment and performs the second cable tensioning in parallel with the segment preceding it. The second cable tensioning is completed before the bridge deck crane reaches its position. After hoisting the bridge deck, the reinforcement at the bridge deck wet joints can be tied, and this is completed before pouring the wet joints. For odd-numbered segments, when the bridge deck crane moves forward to the current segment, the second cable tensioning of the previous segment, the tying of the reinforcement at the bridge deck wet joints, and the hydraulic device moving up two segments are performed. These three processes are carried out in parallel with the steel main girder hoisting and welding, and are completed before the installation of the crossbeams and small longitudinal beams.

2. The method for constructing composite beams that ignores the equal strength time of wet joints in standard segments according to claim 1, characterized in that: The main longitudinal beams corresponding to each main beam segment are all box-shaped or I-shaped cross sections, and the segments are connected by welding or bolts.

3. The method for constructing composite beams that ignores the equal strength time of wet joints in standard segments according to claim 1, characterized in that: In the first cable tensioning process corresponding to each main beam segment, the internal force of the tensioned cable is controlled to a preset value. In the second cable tensioning process corresponding to each main beam segment, the anchor head pull-out amount of the tensioned cable is controlled to a preset value. The two tensioning processes are coordinated with the segment elevation as auxiliary control.

4. The method for constructing composite beams that ignores the equal strength time of wet joints in standard segments according to claim 1, characterized in that: After the wet joint pouring process of the even-numbered construction segments, the next segment's construction cycle begins.

5. The method for constructing composite beams that ignores the equal strength time of wet joints in standard segments according to claim 1, characterized in that: The second cable-stayed connection process for the last two main girder segments is carried out after all the wet joints of the bridge deck have been poured.

6. The method for constructing composite beams that ignores the equal strength time of wet joints in standard segments according to claim 1, characterized in that: The alignment of the completed segments is fine-tuned by using the second cable lag of one segment.

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