A method for bridge erection in shallow overburden hard rock geological conditions

Abstract

This application relates to the technical field of bridge construction and proposes a bridge construction method for shallow overburden hard rock geological conditions, including the following steps: S1: Construction of the steel-concrete composite section; S2: Construction of the leveling layer; S3: Assembly of temporary supports; S4: Hoisting of the initial section temporary supports; S5: Hoisting of the initial section steel box girder; S6: Connecting the steel-concrete composite section and the initial section steel box girder; S7: Hoisting of the standard section temporary supports; S8: Hoisting of the standard section steel box girder; S9: Connecting adjacent standard section steel box girders; S10: Repeating steps S7-S9 until the installation of the standard section steel box girder is completed; S12: Hoisting of the closure section steel box girder; S13: Connecting both ends of the closure section steel box girder to the standard section steel box girder and the steel-concrete composite section respectively; S14: Removing the temporary steel supports; S15: Removing the temporary supports. This application has the effect of facilitating bridge construction on river channels with shallow overburden hard rock geological conditions.

Description

Technical Field

[0001] This application relates to the field of bridge construction, and in particular to a method for bridge construction in shallow overburden hard rock geological conditions. Background Technology

[0002] In related technologies, conventional cross-river bridges are usually erected using the steel pipe pile support method. In specific construction, steel pipe pile supports are first driven into the river channel, and then steel box girders are erected between adjacent steel pipe pile supports to complete the erection of the cross-river bridge.

[0003] Currently, constructing bridges across rivers with shallow overburden hard rock geology using the steel pipe pile support method presents significant challenges. This is because the overall hardness of the shallow overburden hard rock strata is high, making it impossible to secure the steel pipe piles using conventional driving methods. It requires first drilling holes in the rock strata using a drilling machine before inserting the steel pipe piles and then pouring concrete to fix them in place. This process is quite complex, and before drilling holes in the rock strata, a drilling platform must be erected on the river using large engineering vessels, further complicating the process and increasing construction costs. Summary of the Invention

[0004] To facilitate bridge construction on rivers with shallow overburden hard rock geology, this application provides a bridge construction method for shallow overburden hard rock geological conditions.

[0005] This application provides a bridge erection method for shallow overburden hard rock geological conditions, which adopts the following technical solution:

[0006] A bridge erection method for shallow overburden hard rock geological conditions includes the following steps:

[0007] S1: Construction of steel-concrete composite section: Temporary steel supports are erected on the abutments at both ends of the bridge, and the steel-concrete composite section is installed on the temporary steel supports;

[0008] S2: Leveling layer construction: Stone rubble is dumped at the location of the temporary support in the river channel to form a leveling layer;

[0009] S3: Temporary scaffold assembly: Assemble temporary scaffolds used to support the steel box girder;

[0010] S4: Initial temporary support hoisting: The temporary support used to support the initial steel box girder is hoisted and placed onto the corresponding leveling layer on the riverbed;

[0011] S5: Initial steel box girder hoisting: Hoist the initial steel box girder and lap it on the temporary steel piers and temporary supports at both ends respectively;

[0012] S6: Connects the steel-concrete composite section and the initial steel box girder;

[0013] S7: Erection of temporary supports for standard sections: The temporary supports used to support the steel box girders of standard sections are hoisted and placed onto the corresponding leveling layer on the riverbed;

[0014] S8: Standard section steel box girder hoisting: Hoist the standard section steel box girder and lap it on the adjacent temporary supports at both ends;

[0015] S9: Connects adjacent standard steel box girders;

[0016] S10: Repeat steps S7-S9 until the installation of the standard section steel box girder is completed;

[0017] S11: Hoisting of the closure section steel box girder: Hoist the closure section steel box girder and lap it on the temporary support and temporary steel pier at both ends respectively;

[0018] S12: Connect both ends of the closure section steel box girder to the standard section steel box girder and the steel-concrete composite section respectively;

[0019] S13: Remove the temporary steel support piers;

[0020] S14: Remove the temporary support.

[0021] By adopting the above technical solution, temporary supports are used instead of traditional steel pipe pile supports to support the steel box girder. This eliminates the need to use drilling machines to drill steel pipe pile foundations in the river channel, reducing the impact on the river environment and mitigating the difficulties encountered in constructing steel pipe pile supports in rivers with shallow overburden hard rock geology. Furthermore, it eliminates the need to build a drilling platform in the river channel, simplifying the overall bridge erection process and facilitating bridge erection in rivers with shallow overburden hard rock geology. In addition, the temporary supports can be assembled on the ground and then hoisted into the river channel as a whole, eliminating the need for assembling temporary supports on the water surface, further reducing the overall construction difficulty of the bridge.

[0022] Preferably, in steps S4 and S7, after the temporary support is hoisted, a distribution beam is installed on the top of the temporary support and several support rods for supporting the steel box girder are welded and fixed on the distribution beam;

[0023] In steps S5 and S8, when the steel box girder is hoisted, the bottom side of the end of the steel box girder is overlapped with several support rods of the distribution beam.

[0024] By adopting the above technical solution, by having the bottom side of the steel box girder end overlap the support rod on the distribution beam, on the one hand, the distribution beam and several support rods can assist in supporting the steel box girder, which helps to distribute the gravity load of the steel box girder more evenly on the temporary support. On the other hand, several support rods can be used to push the steel box girder away from the top end of the temporary support, which facilitates the subsequent connection of adjacent steel box girders and the butt welding and fixing of the adjacent steel box girders at their closest ends.

[0025] Preferably, in steps S5 and S8, after the bottom side of the end of the steel box girder overlaps with several support rods of the distribution beam, the support rods are welded and fixed to the steel box girder.

[0026] By adopting the above technical solution, after the steel box girder is placed, the support rods are welded and fixed to the bottom side of the steel box girder. Several support rods are used to limit and fix the steel box girder, thereby restricting the subsequent displacement of the steel box girder due to external loads, and making it easier for the steel box girder to be erected more stably on the top of the temporary support.

[0027] Preferably, in step S3, after the temporary support is assembled, several sandbags are placed at the bottom of the temporary support.

[0028] By adopting the above technical solution, several sandbags are used to increase the self-weight of the bottom of the temporary support, which helps to improve the stability of the bottom of the temporary support and reduce the possibility of displacement of the temporary support due to external load or water flow impact after it is subsequently hoisted on the river. This helps to make the temporary support more stably supported on the river.

[0029] Preferably, in step S3, before placing sandbags at the bottom of the temporary support, a net bag is first stretched and tied at the bottom of the temporary support, and then the sandbags are placed into the net bag.

[0030] By adopting the above technical solution, a net bag is first tensioned and tied at the bottom of the support, and then sandbags are placed into the net bag. The net bag is used to limit the position of several sandbags, reducing the possibility of sandbags detaching from the bottom of the temporary support during the subsequent hoisting and placement of the temporary support. At the same time, when the temporary support is subsequently removed from the bottom of the steel box girder, the temporary support can bring several sandbags out together through the net bag, reducing the possibility of sandbags scattering on the bottom of the river and causing environmental pollution.

[0031] Preferably, in steps S4 and S7, after the temporary support is hoisted, before installing the distribution beam on top of the temporary support, concrete pre-compression blocks are hoisted onto the top of the temporary support for pre-compression treatment.

[0032] By adopting the above technical solution, concrete pre-stressing blocks are suspended on the top of the temporary support to pre-stress the concrete blocks, thereby testing the stability and load-bearing capacity of the support. At the same time, the pre-stressing treatment of the temporary support can eliminate the inelastic deformation of the temporary support, reduce the settlement that may occur during the subsequent use of the temporary support, improve the overall stability of the support, and facilitate the temporary support to better support the steel box girder.

[0033] Preferably, in step S15, when dismantling the temporary support, the connection between the support rod and the bottom of the steel box girder is first disconnected, then the distribution beam and the top part of the temporary support are dismantled, and finally the temporary support is pulled out from the bottom of the steel box girder by a tugboat.

[0034] By adopting the above technical solution, the overall height of the temporary support is reduced by removing the top part of the temporary support. This helps to reduce the interference between the temporary support and the bottom of the steel box girder when the tugboat drags the temporary support during the subsequent dismantling of the bottom support of the steel box girder, and makes it easier to pull the temporary support out smoothly from the bottom of the steel box girder.

[0035] Preferably, the temporary support is assembled from several universal rods.

[0036] By adopting the above technical solution, the temporary supports are assembled from universal rods, which facilitates the assembly and repeated use of the temporary supports. On the other hand, the temporary supports can be assembled into various specifications of frame-shaped expanded foundations according to actual construction needs, which helps to improve the overall adaptability of the temporary supports.

[0037] In summary, this application includes at least one of the following beneficial technical effects:

[0038] 1. Taking advantage of the geological characteristics of the shallow overburden hard rock in the riverbed, which has high hardness and is not easy to settle, a temporary support assembled from universal rods is hoisted and installed on the riverbed. The temporary support is used to temporarily support the steel box girder that is subsequently hoisted. There is no need to build a drilling platform on the riverbed and drill steel pipe piles for the foundation installation, which simplifies the overall construction steps, reduces the overall construction difficulty of bridge erection, and reduces the impact on the normal environment of the riverbed during construction.

[0039] 2. By placing concrete prestressing blocks on top of the temporary support after it has been positioned, the temporary support can be prestressed. This helps to eliminate the overall inelastic deformation of the temporary support, reduce subsequent settlement, and improve the overall stability of the temporary support.

[0040] 3. When hoisting the steel box girder, the bottom side of the end of the steel box girder should abut against several support rods of the distribution beam, and the support rods should be welded and fixed to the bottom side of the end of the steel box girder. On the one hand, the steel box girder can be supported by several distribution beams and several support rods, so that the self-weight load of the steel box girder is evenly distributed on the top of the temporary support. On the other hand, the support rods can limit and fix the steel box girder to restrict the displacement of the steel box girder under external load. At the same time, the support rods on the distribution beam can also push the end of the steel box girder away from the top of the temporary support, so as to facilitate the subsequent butt welding construction of adjacent steel box girders. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the state when a temporary support is hoisted and placed, as shown in the embodiments of this application.

[0042] Figure 2 This is a schematic diagram illustrating the use of concrete blocks to preload temporary supports, as described in the embodiments of this application.

[0043] Figure 3 This is a schematic diagram illustrating the application of a support on a temporary scaffold, as described in the embodiments of this application.

[0044] Figure 4 This is a schematic diagram illustrating the state of the initial steel box girder being hoisted in an embodiment of this application.

[0045] Figure 5 This is a schematic diagram illustrating the state of the connection between the support and the steel box girder in an embodiment of this application.

[0046] Figure 6 This is a schematic diagram illustrating the state of hoisting a standard section of steel box girder in an embodiment of this application.

[0047] Figure 7 This is a schematic diagram of the completed steel box girder hoisting state in an embodiment of this application.

[0048] Figure 8 This is a schematic diagram illustrating the state after the steel support and temporary support have been removed, as shown in the embodiments of this application.

[0049] Explanation of reference numerals in the attached figures:

[0050] 1. Foundation; 11. Temporary steel support; 12. Steel-concrete composite section; 2. Leveling layer; 3. Temporary support; 30. Sandbags; 31. Support; 311. Distribution beam; 312. Support rod; 4. Crawler crane; 5. Concrete prestressing block; 6. Steel box girder. Detailed Implementation

[0051] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0052] This application discloses a bridge erection method for shallow overburden hard rock geological conditions, including the following steps:

[0053] S1: Construction of steel-concrete composite section 12: Refer to Figure 1 and Figure 2 Temporary steel supports 11 are erected on the abutments 1 at both ends of the bridge, and the steel-concrete composite section 12 is hoisted onto the steel frame.

[0054] S2: Leveling layer 2 construction: Using a stone-throwing leveling boat, stones are thrown and filled to the design elevation at the locations of temporary supports 3 in various parts of the river channel to form leveling layer 2; after the leveling layer 2 is completed, buoys are used to mark the water surface in this area.

[0055] The setting of leveling layer 2 can, on the one hand, level the bottom of the riverbed, and on the other hand, the leveling layer 2 formed by dumping rubble can squeeze away the silt on the surface of the riverbed.

[0056] S3: Assembly of temporary support 3: Assemble temporary support 3 for supporting steel box girder 6; temporary support 3 is assembled from several universal rods. In other embodiments, temporary support 3 may also be manufactured by assembling steel components.

[0057] The specific steps of step S3 are as follows:

[0058] S3.1: Temporary support 3 is assembled with universal rods to connect with the ground;

[0059] S3.2: Tension and install a net bag at the bottom of the temporary support 3. In this embodiment, the net bag is a metal net bag. When tensioning and installing the net bag, make the bottom of the net bag higher than the bottom end of the temporary support 3.

[0060] S3.3: Fill the net bag with several sandbags 30, and seal the net bag after filling the sandbags 30.

[0061] S3.4: Repeat steps S3.1 to S3.4 until the remaining temporary support 3 is erected.

[0062] S4: Lifting of the initial temporary support 3: The temporary support 3, used to support the initial steel box girder 6, is lifted and placed onto the corresponding leveling layer 2 in the river channel; the specific steps are as follows:

[0063] S4.1: On the steel-concrete composite section 12, the temporary support 3 used to support the initial steel box girder 6 is lifted by the crawler crane 4 and moved to the upper part of the corresponding leveling layer 2;

[0064] S4.2: Lower the temporary support 3 using the crawler crane 4 until the temporary support 3 is placed on the corresponding leveling layer 2;

[0065] S4.3: Disconnect the crawler crane 4 from the temporary support 3;

[0066] S4.4: Pre-stressing of temporary support 3: Several concrete pre-stressing blocks 5 are lifted onto temporary support 3 by crawler crane 4 to pre-stress temporary support 3, which helps to eliminate the inelastic deformation of temporary support 3 and reduce settlement of temporary support 3 during temporary construction; after pre-stressing is completed, several concrete pre-stressing blocks 5 on the top of temporary support 3 are lifted off the top of temporary support 3 one by one by crawler crane 4.

[0067] S4.5: Reference Figure 3 and Figure 4 Support 31 installation: Weld distribution beam 311 to the bottom of the support and make distribution beam 311 extend to both sides of temporary support 3; weld several vertically upward support rods 312 on distribution beam 311, the support rods 312 are used to support steel box girder 6.

[0068] By tensioning and installing a net bag at the bottom of the temporary support 3 and filling the net bag with sandbags 30, the weight of the bottom of the temporary support 3 is increased by the sandbags 30. After the temporary support 3 is lowered into the river, this helps to improve the stability of the bottom of the temporary support 3, reduce displacement of the temporary support 3 due to water flow impact or external load, and help to support the temporary support 3 more stably in the river. The net bag also helps to limit the sandbags 30 at the bottom of the support, so as to reduce the possibility of the sandbags 30 detaching from the bottom of the temporary support 3 during the subsequent lowering process.

[0069] S5: Hoisting of the initial steel box girder 6: The initial steel box girder 6 is hoisted on the steel-concrete composite section 12 by crawler crane 4, and the two ends of the initial steel box girder 6 are respectively connected to the support rods 312 of the temporary steel support 11 and the temporary bracket 3.

[0070] After the initial steel box girder 6 is attached to the support rod 312, the top of the support rod 312 is welded and fixed to the bottom side of the initial steel box girder 6 so as to limit and fix the steel box girder 6 through the support rod 312, thereby reducing the displacement of the steel box girder 6 due to external loads.

[0071] S6: Connecting the steel-concrete composite section 12 and the initial steel box girder 6: Butt welding is performed on the closest ends of the initial steel box girder 6 and the steel-concrete composite section.

[0072] S7: Lifting of temporary support 3 for standard section: Lifting the temporary support 3 used to support the steel box girder 6 for standard section onto the corresponding leveling layer 2 on the river channel; The specific steps of step S7 are the same as those of step S4, so they will not be described again.

[0073] S8: Standard section steel box girder 6 hoisting, refer to... Figure 5 and Figure 6 The specific steps are as follows:

[0074] S8.1: The standard section of the steel box girder 6 is hoisted onto the installed steel box girder 6 by the crawler crane 4, and the bottom sides of both ends of the standard section of the steel box girder 6 are respectively attached to the support rods 312 at the top of the adjacent temporary supports 3;

[0075] S8.2: The top of the support rod 312 is welded to the bottom side of the standard section steel box girder 6 to limit and fix the steel box girder 6 through the support rod 312, thereby reducing the displacement of the steel box girder 6 due to external loads.

[0076] S9: Connect adjacent standard section steel box girders 6; butt weld the two adjacent steel box girders 6 at their closest ends.

[0077] S10: Repeat steps S7-S9 until the installation of standard section steel box girder 6 is completed.

[0078] S11: Lifting of the closure section steel box girder 6: The closure section steel box girder 6 is lifted onto the already installed steel box girder 6 using a crawler crane 4, with both ends of the girder 6 lapped onto the support rod 312 of the temporary support 3 and the temporary steel support pier 11, respectively. After the closure section steel box girder 6 is in place, the top of the support rod 312 is positioned on the bottom side of the closure section steel box girder 6.

[0079] S12: Weld the two ends of the closure section steel box girder 6 to the standard section steel box girder 6 and the steel-concrete composite section 12 respectively;

[0080] S13: Reference Figure 7 and Figure 8 Remove 11 temporary steel supports;

[0081] S14: Remove temporary support 3; refer to Figure 5 and Figure 7 The specific steps are as follows:

[0082] S14.1: Cut off the top of the support rod 312 using an angle grinder to disconnect the support rod 312 from the steel box girder 6.

[0083] S14.2: Remove the distribution beam 311 and support rod 312 from the top of the temporary support 3;

[0084] S14.3: Remove the top part of the universal rod of temporary support 3 to reduce the overall height of temporary support 3;

[0085] S14.4: Temporary stent 3 removed.

[0086] The specific steps of step S14.4 are as follows:

[0087] S14.4.1: Large tugboat positioning: After the large tugboat is moved to the designated waters, the large tugboat is anchored and positioned.

[0088] S14.4.2: At least two large winches shall be installed on large tugboats;

[0089] S14.4.3: Connect the cables of the large winch on the large tugboat to the top and bottom of the temporary support 3 respectively, and pull the temporary support 3 with the large winch until the temporary support 3 is removed from the bottom of the steel box girder 6;

[0090] S14.4.4: Disconnect the large winch from the temporary support 3;

[0091] S14.4.5 The temporary support 3 is lifted off using a floating crane.

[0092] This application utilizes the geological characteristics of river channels with shallow overburden hard rock geology. It replaces the traditional steel pipe pile support with a temporary support 3 formed by assembling universal rods to support the steel box girder 6. This eliminates the need for drilling the steel pipe pile foundation in the river channel using a drilling machine, and also eliminates the need to build a drilling platform in the river channel. This simplifies the overall construction process and reduces the impact on the normal environment of the river channel during construction. It also helps to reduce the construction difficulty of bridge erection in river channels with shallow overburden hard rock geology.

[0093] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bridge erection method for shallow overburden hard rock geological conditions, characterized in that: Includes the following steps: S1: Construction of steel-concrete composite section (12): Temporary steel supports (11) are erected on the abutments (1) at both ends of the bridge, and the steel-concrete composite section (12) is installed on the temporary steel supports (11); S2: Leveling layer (2) construction: Fill the temporary support (3) on the river channel with rubble to form leveling layer (2); S3: Temporary support (3) assembly: Assemble the temporary support (3) used to support the steel box girder (6); S4: Lifting of the temporary support (3) for the initial section: Lift the temporary support (3) used to support the steel box girder (6) of the initial section onto the corresponding leveling layer (2) on the river channel; S5: Hoisting of the initial steel box girder (6): Hoist the initial steel box girder (6) and lap it on the temporary steel support (11) and the temporary support (3) at both ends respectively; S6: Connects the steel-concrete composite section (12) and the initial steel box girder (6); S7: Standard section temporary support (3) hoisting: hoist the temporary support (3) used to support the standard section steel box girder (6) onto the corresponding leveling layer (2) on the river channel; S8: Standard section steel box girder (6) hoisting: hoist the standard section steel box girder (6) and make its two ends overlap on the adjacent temporary support (3); S9: Connects adjacent standard section steel box girders (6); S10: Repeat steps S7-S9 until the installation of the standard section steel box girder (6) is completed; S11: Hoisting of the closure section steel box girder (6): Hoist the closure section steel box girder (6) and connect its two ends to the temporary support (3) and the temporary steel support (11) respectively; S12: Connect the two ends of the closure section steel box girder (6) to the standard section steel box girder (6) and the steel-concrete composite section (12) respectively; S13: Remove the temporary steel support pier (11); S14: Remove the temporary support (3), the specific steps are as follows: In steps S4 and S7, after the temporary support (3) is hoisted, a distribution beam (311) is installed on the top of the temporary support (3) and several support rods (312) for supporting the steel box girder (6) are welded and fixed on the distribution beam (311); In steps S5 and S8, when the steel box girder (6) is hoisted, the bottom side of the end of the steel box girder (6) is overlapped on several support rods (312) of the distribution beam (311); In steps S5 and S8, after the bottom side of the end of the steel box girder (6) is lapped on several support rods (312) of the distribution beam (311), the support rods (312) and the steel box girder (6) are welded and fixed. The specific steps of step S14 are as follows: S14.1: Cut off the top of the support rod (312) with an angle grinder to disconnect the support rod (312) from the steel box girder (6); S14.2: Remove the distribution beam (311) and support rod (312) from the top of the temporary support (3); S14.3: Remove the top part of the universal rod of the temporary support (3) to reduce the overall height of the temporary support (3); S14.4: Temporary stent (3) removed; The specific steps of step S14.4 are as follows: S14.4.1: Large tugboat positioning: After the large tugboat is moved to the designated waters, the large tugboat is anchored and positioned. S14.4.2: At least two large winches shall be installed on large tugboats; S14.4.3: Connect the cables of the large winch on the large tugboat to the top and bottom of the temporary support (3) respectively, and drag the temporary support (3) with the large winch until the temporary support (3) is removed from the bottom of the steel box girder (6); S14.4.4: Disconnect the large winch from the temporary support (3); S14.4.5 The temporary support (3) is lifted off using a floating crane; In step S3, after the temporary support (3) is assembled, several sandbags (30) are placed at the bottom of the temporary support (3); In step S3, before placing sandbags (30) at the bottom of the temporary support (3), first stretch and tie a net bag at the bottom of the temporary support (3), and then put the sandbags (30) into the net bag.

2. The bridge erection method for shallow overburden hard rock geological conditions according to claim 1, characterized in that: In steps S4 and S7, after the temporary support (3) is hoisted, before installing the distribution beam (311) on the top of the temporary support (3), concrete pre-compression blocks (5) are hoisted onto the top of the temporary support (3) for pre-compression treatment.

3. The bridge erection method for shallow overburden hard rock geological conditions according to claim 1, characterized in that: The temporary support (3) is assembled from several universal rods.

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