A method for constructing a cross-river waterway steel box girder with inverted hole erection.

Abstract

The present application relates to the technical field of steel box girder construction across rivers. In view of the traditional need to repeatedly insert temporary supports on the river surface when erecting steel box girder segments at navigation holes, a pontoon is set at the navigation hole and a temporary support is set on the pontoon. The steel box girder segments can be temporarily supported by the temporary support when erecting the steel box girder segments. Water can be added to the pontoon to lower the steel box girder segments. After the subsequent steel box girder segments are lowered, water is continued to be injected into the pontoon to cause the pontoon to sink and drive the temporary support to detach from the steel box girder segments. The pontoon and the temporary support can then be quickly moved to the next navigation hole. The present application has the effect of avoiding the need to repeatedly insert temporary supports when constructing steel box girder segments at navigation holes.

Description

Technical Field

[0001] This application relates to the technical field of cross-river steel box girder construction, and in particular to a method for constructing cross-river waterway steel box girder with inverted hole erection. Background Technology

[0002] When the main span of a large municipal bridge crosses a navigable river channel, the steel box girder segments are typically erected segment by segment using a large floating crane and steel pipe support method. The construction steps are as follows: Several temporary supports are constructed between two adjacent concrete piers to form multiple navigation channels. Temporary supports (used for temporary support during the erection of steel box girder segments) are erected between adjacent temporary supports using the inverted hole method. Temporary supports are installed on one group of navigation channels at a time (the remaining navigation channels need to allow normal passage for ships on the river). The pre-welded steel box girder segments are hoisted onto the temporary supports using a large floating crane, and the two ends of the steel box girder segments are respectively abutted against the adjacent temporary supports. The erection of the steel box girder segments above the navigation channels is completed. Afterwards, the temporary supports on the navigation channels are removed, and normal navigation of the navigation channels is restored. The same steps are then used to continue to complete the erection of steel box girder segments at the remaining navigation channels.

[0003] Regarding the aforementioned technologies, when erecting the steel box girder segments above the navigation channel, it is necessary to repeatedly insert and remove the steel pipe piles of the temporary support using a vibratory hammer to achieve the installation and dismantling of the temporary support, which results in a long construction period and seriously affects the construction progress. Summary of the Invention

[0004] To reduce the need for repeated temporary supports to be installed on the river surface when erecting steel box girder segments at navigation channels, this application provides a method for constructing steel box girder cross-river channels by inverting the holes.

[0005] This application provides a method for constructing a cross-river channel steel box girder with inverted hole erection, which adopts the following technical solution:

[0006] A method for constructing a cross-river waterway steel box girder with inverted hole erection includes the following steps:

[0007] S1: Navigation channel construction: Construct several temporary supports in the river channel to form a navigation channel;

[0008] S2: Construct a floating pontoon as a construction platform on the navigation channel, and erect temporary supports on the deck of the pontoon, with the top elevation of the temporary supports being higher than the top elevation of the temporary supports.

[0009] S3: Assemble steel box girder segments on top of the temporary support;

[0010] S4: Lowering of steel box girder segments: Slowly fill the pontoon with water, and gradually lower the pontoon until the steel box girder segment at the top of the temporary support is lowered to the top of the temporary support.

[0011] S5: Continue filling the pontoon with water until the temporary support on the pontoon comes loose, then pull the pontoon out from between the two adjacent temporary supports.

[0012] S6: Adjust the position of the steel box girder segment to match the installed steel box girder segment and weld it in place;

[0013] S7: Move the pontoon to the next navigation hole;

[0014] S8: Repeat steps S3-S6 until the erection of all steel box girder segments above the navigation holes is completed.

[0015] By adopting the above technical solution, this application utilizes pontoons and supports erected on them to facilitate temporary support of steel box girder segments during construction. Simply adding water to the pontoons causes the temporary supports and steel box girder segments to move downwards, allowing them to be lowered to the top of the temporary supports. After subsequent steel box girder segments are completed, adding water to the pontoons again causes them to detach from the temporary supports, and then a tugboat tows the pontoons to the next navigation channel, enabling rapid assembly and disassembly of the temporary supports. Compared to traditional borehole construction, which requires repeated driving of steel pipe piles for temporary supports, this significantly reduces the construction time spent assembling and disassembling temporary supports on adjacent navigation channels, shortening the overall construction period. The pontoons and their temporary supports can be reused multiple times, greatly reducing the investment in steel structure materials.

[0016] Preferably, in S2, after the temporary support is erected, anti-pull piles are driven into the water around the pontoon and the temporary support is pulled taut onto several anti-pull supports by cables to limit the position of the temporary support.

[0017] In S3, before filling the pontoon with water, untie the cables and disconnect the temporary support from the pull-out piles.

[0018] By adopting the above technical solution, after the temporary support is erected, the temporary support is tightened to the anti-uplift pile by the cable, thereby limiting the position of the temporary support on the pontoon and reducing the possibility of the temporary support swaying and colliding with the temporary support due to water flow and other reasons.

[0019] Preferably, in S3, when assembling the steel box girder segments, the steel box girder units are hoisted to the top of the temporary support in multiple stages by a floating crane, and adjacent steel box girders are circumferentially welded to form steel box girder segments.

[0020] By adopting the above-mentioned scheme, compared with the traditional method of lifting steel box girder segments all at once using a large floating crane, this application lifts the steel box girder units onto the support in multiple stages using a floating crane and then splices them to form steel box girder segments. Compared with the traditional method of completing the welding of steel box girder segments on the ground and then lifting them onto the support using a large floating crane, this method helps to reduce the limitations of large floating crane operations due to factors such as river width and water depth. At the same time, it is safer than the traditional method of lifting large steel box girder segments.

[0021] Preferably, the temporary support is provided with several brackets on opposite sides of the top. The brackets are used to support the steel box girder unit at the cantilever end of the steel box girder segment. The brackets include horizontal and diagonal braces hinged to the side of the temporary support. The horizontal and diagonal braces are axially parallel. The end of the diagonal brace away from the temporary support is detachably connected to the end of the horizontal brace away from the temporary support through a connector to support the horizontal brace.

[0022] In S3, when hoisting the steel box girder unit at the cantilever end of the steel box girder segment, the horizontal brace is swung to a horizontal state and the diagonal brace is connected to the horizontal brace through the connector to realize the erection of the corbel bracket;

[0023] In S4, before the steel box girder segment is lowered, the connecting parts between the horizontal and diagonal braces are removed, and the horizontal and diagonal braces are swung downwards to accommodate the corbel bracket.

[0024] By adopting the above technical solution, when assembling the steel box girder unit at the cantilever end of the steel box girder segment on the top of the temporary support using the bracket, the horizontal brace is swung to a horizontal state, and the diagonal brace is connected to the horizontal brace through the connector to realize the erection of the bracket. The bracket provides temporary support for the steel box girder unit at the cantilever end of the steel box girder segment, which facilitates better welding of the steel box girder unit at the cantilever end. Before the subsequent steel box girder segment is disassembled, the connector is removed and the horizontal and diagonal braces are swung downward, so that the cantilever end of the steel box girder segment can extend outside the support, which facilitates the smooth lowering of the cantilever end of the subsequent steel box girder segment to the top of the corresponding temporary support. At the same time, when the pontoon is moved out of the navigation hole later, it helps to reduce the interference and collision between the bracket and the temporary support.

[0025] Preferably, the bottom of the cross brace is provided with an ear plate, and the connector includes a pin, which passes through the ear plate and the end of the diagonal brace away from the temporary support.

[0026] By adopting the above technical solution, when it is necessary to support the bracket, the bracket can be erected by connecting the ear plate and the diagonal brace with a pin. Before lowering the steel box girder segment, the pin between the ear plate and the diagonal brace is removed, and the horizontal brace and diagonal brace can be swung downward to store the bracket, making the support and storage of the bracket simpler and more convenient.

[0027] Preferably, in S4, before the steel box girder segment is lowered, a distribution beam is installed at the top of the adjacent temporary support, and multiple sets of three-way jacks are installed on the distribution beam.

[0028] By adopting the above technical solution, and by installing three-way jacks on the top of the temporary support, the steel box girder segments can be placed on the temporary support and then precisely adjusted using the three-way jacks, so that the steel box girder segments on the navigation channel can be matched with the already safe steel box girder segments.

[0029] Preferably, the pontoon is assembled from several standard boxes, and any adjacent standard boxes are connected by standard connectors.

[0030] By adopting the above technical solution, the pontoon does not need to be integrally formed, which facilitates the assembly of the pontoon according to the actual construction needs. In step S3, after each set of steel box girder units is hoisted to the top of the support, a standard box can be added appropriately according to the elevation of the top of the temporary support at this time to increase the contact area between the pontoon and the river surface, thereby improving the buoyancy of the pontoon and ensuring that the steel box girder segment is always higher than the top of the temporary support during the assembly process.

[0031] Preferably, in S2, after the pontoon is erected, a base frame is fixed on the deck surface of the pontoon. The fixed base frame includes several crisscrossing longitudinal beams and transverse beams, and several of the longitudinal beams and transverse beams are fixed on the deck surface of the pontoon.

[0032] By adopting the above technical solution and setting up a fixed base frame, on the one hand, it is convenient to further limit the adjacent standard containers through the fixed base frame, making the pontoon more stable and reliable. On the other hand, when setting up temporary supports later, the bottom end of the temporary supports can be welded and fixed to the longitudinal beam and the bottom beam, so that the temporary supports can be more stably supported on the pontoon.

[0033] In summary, this application includes at least one of the following beneficial technical effects:

[0034] 1. By setting up pontoons at navigation holes and installing temporary supports on the pontoons, the steel box girder segments can be temporarily supported by the temporary supports. Water can be added to the pontoons to lower the steel box girder segments. After the subsequent steel box girder segments are completed, water can be added to the pontoons to make them sink and move the temporary supports away from the steel box girder segments. The pontoons and temporary supports can then be quickly moved to the next navigation hole. Compared with the traditional method of installing temporary supports by inserting and pulling steel pipe piles with a vibratory hammer, this method can better shorten the overall construction period.

[0035] 2. Several corbel brackets are installed on the side of the temporary support facing the temporary pier. The corbel brackets include horizontal and diagonal braces that are hinged to the top side of the temporary support. The end of the diagonal brace away from the temporary support is connected to the horizontal brace through a connector to support the horizontal brace. The corbel brackets temporarily support the steel box girder unit at the cantilever end of the steel box girder segment, which facilitates better welding of the steel box girder unit at the cantilever end of the steel box girder segment on the support. After the steel box girder segment is assembled, the connector is removed and the horizontal and diagonal braces are swung downward to realize the storage of the corbel brackets. This allows the cantilever end of the steel box girder segment to extend outside the support, and at the same time reduces the possibility of collision between the corbel brackets of the temporary support and the temporary pier when the temporary support is moved out from between adjacent temporary piers.

[0036] 3. By installing three-way jacks on temporary supports before lowering the steel box girder segments, and then lowering the steel box girder segments onto the three-way jacks on top of the temporary supports, the position of the steel box girder segments can be finely adjusted using the three-way jacks, thereby facilitating the matching of the steel box girder segments on the navigation channel with the installed steel box girder segments. Attached Figure Description

[0037] Figure 1 This is a schematic diagram used in this application to illustrate the construction of navigation channels.

[0038] Figure 2 This is a schematic diagram used in this application to illustrate the assembly of steel box girder segments on temporary supports in S3.

[0039] Figure 3 This is a schematic diagram used in this application to illustrate the state of the steel box girder segment in S4.

[0040] Figure 4 This is a top view of the pontoon in this application.

[0041] Figure 5 This is a front view used in this application to illustrate the pontoon and temporary support structure.

[0042] Figure 6 This is a side view used in this application to illustrate the pontoon and temporary support.

[0043] Figure 7 This is a schematic diagram used in this application to illustrate the state of the bracket support during its installation.

[0044] Figure 8 This is a schematic diagram used in this application to illustrate the state of the bracket when it is stored.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1. Temporary support pier; 11. Navigation channel; 2. Floating box; 21. Standard box; 22. Fixed base frame; 3. Temporary support; 4. Steel box girder segment; 41. Steel box girder unit; 5. Horizontal brace; 50. Ear plate; 51. Diagonal brace; 52. Pin. Detailed Implementation

[0047] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0048] This application discloses a method for constructing a cross-river waterway steel box girder with inverted hole erection.

[0049] A method for constructing a cross-river waterway steel box girder with inverted hole erection includes the following steps:

[0050] Reference Figure 1 and Figure 2 S1: Construction of navigation channel 11: Several temporary supports 1 are constructed in the river channel to form a navigation channel 11.

[0051] Reference Figure 2 and Figure 3 A floating box 2 is erected on the navigation hole 11 as a construction platform on the water, and a temporary support 3 is erected on the deck of the floating box 2. The top elevation of the temporary support 3 is higher than the top elevation of the temporary support 1.

[0052] Reference Figure 2 and Figure 3 The pontoon 2 is configured according to the weight of the steel box girder segment 4 it supports. Due to the limited width of the navigation channel 11, sufficient clearance must be maintained between the pontoon 2 and adjacent temporary supports during its erection to prevent collisions with adjacent temporary supports 1 during movement. In this embodiment, the pontoon 2 is composed of several standard boxes 21 spliced ​​together, with adjacent standard boxes 21 connected by standard joints. This allows for the addition of more standard boxes 21 as needed during actual construction to increase the contact area between the pontoon 2 and the water surface, thereby improving the overall buoyancy of the pontoon 2.

[0053] Reference Figure 3 and Figure 4 After the pontoon 2 is erected, a fixed base frame 22 is erected on the pontoon 2. The fixed base frame 22 includes several crisscrossing longitudinal beams and transverse beams. Both the longitudinal beams and the main beams are made of double-section HN700X300 steel. The longitudinal beams and transverse beams form a mesh frame structure. Several longitudinal beams and transverse beams are welded and fixed to the deck surface of the pontoon 2. This is beneficial for further limiting the adjacent standard boxes 21 through the longitudinal beams and transverse beams of the fixed base frame 22, thereby making the pontoon 2 more stable and reliable as a whole.

[0054] Reference Figure 5 and Figure 6After the fixed base frame 22 is constructed, a temporary support 3 is erected. The temporary support 3 consists of several vertically installed steel pipe piles. During the erection of the temporary support 3, the bottom of the steel pipe piles is welded and fixed to the fixed base frame 22, thereby fixing the temporary support 3 to the pontoon 2. After the temporary support 3 is erected, anti-uplift piles are driven around the pontoon 2, and the temporary support 3 is pulled taut to the anti-uplift piles by steel cables, thereby limiting the movement of the temporary support 3 and the pontoon 2 and reducing the possibility of the pontoon 2 and the temporary support 3 swaying and colliding with the temporary supports 1 on both sides due to water flow and other reasons.

[0055] Reference Figure 7 and Figure 8 Several brackets are provided on both sides of the temporary support 3. The brackets are used to temporarily support the cantilevered end of the steel box girder unit 41 of the steel box girder segment 4. The brackets include horizontal bracing rods 5 and diagonal bracing rods 51. In this embodiment, both the horizontal bracing rods 5 and the diagonal bracing rods 51 are double-channel steel. The diagonal bracing rods 51 are located below the horizontal bracing rods 5. The ends of both the horizontal bracing rods 5 and the diagonal bracing rods 51 that are close to the temporary support 3 are hinged to the temporary support 3. The rotation axes of the diagonal bracing rods 51 and the horizontal bracing rods 5 are parallel. The end of the diagonal bracing rods 51 that is away from the temporary support 3 is connected to the end of the horizontal bracing rods 5 that is away from the support plate through a connector to support the horizontal bracing rods 5.

[0056] Reference Figure 7 and Figure 8 The end of the horizontal brace 5 furthest from the support plate is also provided with an ear plate 50. The connector includes a pin 52, which passes through the end of the diagonal brace 51 furthest from the steel pipe pile and the ear plate 50, so as to support the horizontal brace 5 through the diagonal brace 51. Both the ear plate 50 and the end of the diagonal brace 51 are provided with through holes for the pin 52 to pass through.

[0057] Reference Figure 7 and Figure 8 Remove the pin 52 from the ear plate 50 and the end of the cross brace 5, and the cross brace 5 and diagonal brace 51 can be swung downwards to accommodate the bracket. It is worth noting that when the temporary support 3 is erected, the diagonal brace 51 of the temporary support 3 should be staggered from the steel pipe piles on the temporary support 1 to avoid interference between the cross brace 5 and diagonal brace 51 of the bracket and the steel pipe piles on the temporary support 1 when they swing.

[0058] Reference Figure 2 and Figure 3 S3: Assemble steel box girder segment 4 on top of temporary support 3; the specific operation steps are as follows:

[0059] S3.1: Before hoisting the steel box girder unit 41 at the cantilever end of steel box girder segment 4, swing the horizontal bracing rods 5 on both sides of the temporary support 3 to a horizontal position, and swing the diagonal bracing rod 51 until the through hole of the diagonal bracing rod 51 aligns with the through hole on the ear plate 50. Insert the pin 52 into the through holes of both the diagonal bracing rod 51 and the ear plate 50 in sequence. The horizontal bracing rod 5 can then be supported by the diagonal bracing rod 51, thus achieving the erection of the corbel bracket. This facilitates the subsequent support of the steel box girder unit 41 located at the cantilever end of steel box girder segment 4 via the corbel bracket.

[0060] S3.2: The steel box girder unit 41 is hoisted to the top of the temporary support 3 in multiple stages by a floating crane, and then adjacent steel box girder units 41 are welded to form steel box girder segments 4.

[0061] When steel box girder segment 4 is assembled on the temporary support 3 on the pontoon 2, no water is added to the pontoon 2. The buoyancy of the pontoon 2 without water is ensured by increasing the number of standard boxes 21, that is, increasing the contact area between the pontoon 2 and the water surface, thus resisting the weight of the steel box girder segment 4. After the steel box girder segment 4 is assembled, the top elevation of the pontoon 2 support is at least 1m higher than the temporary supports 1 on both sides of the navigation channel 11.

[0062] S4: Construction of lowering steel box girder segment 4, refer to... Figure 2 and Figure 3 The specific operating steps are as follows:

[0063] S4.1: First, install the distribution beam on the top of the temporary support 1 and install several three-way jacks.

[0064] S4.2: Remove the pins 52 that pass through the ear plate 50 and the end of the diagonal brace 51, and swing the horizontal brace 5 and the diagonal brace 51 downward to realize the storage of the bracket.

[0065] S4.4: Untie the cable between the temporary support 3 and the pull-out pile.

[0066] S4.4: Slowly fill the pontoon 2 with water, and the pontoon 2 will gradually sink until the cantilever end of the steel box girder segment 4 at the top of the temporary support 3 abuts against the piston rod of the Z-axis hydraulic cylinder of the three-way jack at the top of the temporary support 1.

[0067] S5: Continue filling the pontoon 2 with water until the temporary support 3 on the pontoon 2 is detached, and then pull the pontoon 2 out from between the two adjacent temporary supports 1 using a tugboat.

[0068] S6: Fine-tune the position of the steel box girder segment 4 above the navigation hole 11 using the three-way jacks on the temporary support 1, so that it matches and positions with the installed steel box girder segment 4. After the position is adjusted, circumferential weld the steel box girder segment 4 above the navigation hole 11 with the installed steel box girder segment 4.

[0069] S7: Move the pontoon 2 to the next navigation hole 11 by tugboat;

[0070] S8: Repeat steps S3-S6 until the erection of all steel box girder segments 4 above navigation holes 11 is completed.

[0071] This application proposes to erect temporary supports 3 on the pontoon 2, which, compared to the traditional method of erecting temporary supports 3 on navigation holes 11, eliminates the need for repeated driving of steel pipe piles. After the steel box girder segment 4 at navigation hole 11 is erected, the pontoon 2 along with the temporary supports 3 can be moved by tugboat to the next navigation hole 11 to continue construction. This saves the construction time of inserting and removing steel pipe piles of temporary supports 3 at two navigation holes 11, greatly improving construction efficiency. At the same time, this method has a simple construction procedure and is both economical and safe.

[0072] On the other hand, the temporary support 3 on the pontoon 2 can be reused, and multiple navigation holes 11 can be achieved with only one set of structures, reducing the investment in turnover materials such as steel structures.

[0073] The steel box girder is assembled using a cantilevered bracket system. The bracket system temporarily supports the cantilevered end of the steel box girder unit 41 of the steel box girder segment 4. After the steel box girder segment 4 is assembled and connected as a whole, the connecting parts between the horizontal brace 5 and the diagonal brace 51 are removed to store the bracket system. This allows each section of the steel box girder segment 4 to be cantilevered, thus solving the problem of conflict between the steel box girder segment 4 and the temporary supports 1 on both sides of the navigation channel 11 when the girder is lowered.

[0074] Compared to the temporary supports 1 on both sides of the navigation channel 11, the temporary supports 3 on the pontoon 2 can move freely. In this method, neither the pontoon 2 nor the temporary supports 3 are connected to the temporary supports 1, and there is reserved space so that they do not come into contact with each other. Furthermore, the steel box girder segments 4 do not share the load during the erection and installation process. The two support systems are separate. This effectively avoids the disturbance caused by the swaying of the pontoon 2 and the temporary supports 3 due to water flow, floating cranes and other water facilities, which would cause the erected steel box girder segments 4 and the temporary supports 1 to move, thus greatly reducing the safety risk.

[0075] By installing a distribution beam and a three-way jack on the top of the temporary support 1, the position of the steel box girder segment 4 can be precisely adjusted by the three-way jack after the steel box girder segment 4 is lowered.

[0076] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A method for constructing a cross-river waterway steel box girder with inverted hole erection, characterized in that: Includes the following steps: S1: Navigation channel (11) construction: Several temporary supports (1) are constructed in the river channel, and several navigation channels (11) are formed by using the several temporary supports (1); S2: A floating box (2) is erected on the navigation hole (11) as a construction platform on the water, and a temporary support (3) is erected on the deck surface of the floating box (2). The top elevation of the temporary support (3) is higher than the top elevation of the temporary support (1). S3: Assemble the steel box girder segment (4) on top of the temporary support (3); S4: Lowering of steel box girder segment (4): Slowly fill the pontoon (2) with water, and gradually sink the pontoon (2) until the steel box girder segment (4) at the top of the temporary support (3) is lowered to the top of the temporary support (1); S5: Continue to fill the pontoon (2) with water until the temporary support (3) on the pontoon (2) is detached, and pull the pontoon (2) out from between the two adjacent temporary supports (1); S6: Adjust the position of the steel box girder segment (4) to match the installed steel box girder segment (4) and weld it in place; S7: Move the pontoon (2) to the next navigation hole (11); S8: Repeat steps S3-S6 until the erection of all steel box girder segments (4) above the navigation holes (11) is completed; In S3, when assembling the steel box girder segment (4), the steel box girder unit (41) is hoisted to the top of the temporary support (3) in multiple stages by a floating crane, and the adjacent steel box girders are circumferentially welded to form the steel box girder segment (4). The temporary support (3) has several brackets on opposite sides at the top. The brackets are used to support the steel box girder unit (41) at the cantilever end of the steel box girder segment (4). The brackets include a horizontal support rod (5) and a diagonal support rod (51) hinged to the side of the temporary support (3). The horizontal support rod (5) and the diagonal support rod (51) are axially parallel. The end of the diagonal support rod (51) away from the temporary support (3) is detachably connected to the end of the horizontal support rod (5) away from the temporary support (3) through a connector to support the horizontal support rod (5). In S3, when hoisting the steel box girder unit (41) at the cantilever end of the steel box girder segment (4), the horizontal brace (5) is swung to a horizontal state and the diagonal brace (51) is connected to the horizontal brace (5) through the connector to realize the erection of the corbel bracket; In S4, before the steel box girder segment (4) is lowered, the connecting parts between the horizontal brace (5) and the diagonal brace (51) are removed, and the horizontal brace (5) and the diagonal brace (51) are swung downward to realize the storage of the corbel bracket; When the temporary support (3) is erected, the horizontal support rod (5) and the diagonal support rod (51) of the temporary support (3) should be staggered from the steel pipe piles on the temporary support (1) to avoid interference between the horizontal support rod (5) and the diagonal support rod (51) of the bracket and the steel pipe piles on the temporary support (1) when the bracket swings.

2. The method for constructing a cross-river waterway steel box girder with inverted hole erection according to claim 1, characterized in that: In S2, after the temporary support (3) is erected, anti-pull piles are driven into the water around the pontoon (2) and the temporary support (3) is pulled tight to several anti-pull supports by cables to limit the position of the temporary support (3). In S3, before filling the pontoon (2) with water, untie the cable and disconnect the connection between the temporary support (3) and the pull-out pile.

3. The method for constructing a cross-river waterway steel box girder with inverted hole erection according to claim 1, characterized in that: The bottom of the cross brace (5) is provided with an ear plate (50), and the connector includes a pin (52). The pin (52) passes through the ear plate (50) and the end of the diagonal brace (51) away from the temporary support (3).

4. The method for constructing a cross-river waterway steel box girder with inverted hole erection according to claim 1, characterized in that: In S4, before the steel box girder segment (4) is lowered, a distribution beam is installed at the top of the adjacent temporary support (1) and multiple sets of three-way jacks are installed on the distribution beam.

5. The method for constructing a cross-river waterway steel box girder with inverted hole erection according to claim 1, characterized in that: The floating box (2) is assembled from several standard boxes (21), and any adjacent standard boxes (21) are connected by standard connectors.

6. The method for constructing a cross-river waterway steel box girder with inverted hole erection according to claim 5, characterized in that: In S2, after the pontoon (2) is erected, a base frame (22) is fixed on the deck surface of the pontoon (2). The fixed base frame (22) includes several longitudinal beams and transverse beams that are crisscrossed. Several of the longitudinal beams and transverse beams are fixed on the deck surface of the pontoon (2).

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