A splicing construction method for deep-water bridge pier

Abstract

The present invention relates to the field of underwater engineering technology, and discloses a method for splicing and constructing a deep-water bridge pier, which realizes water stopping by providing an opening in a casing so that the casing can be connected to the side wall of an existing pier, and tightening the opening through a tensioning system so that the water stop is pressed against the side wall of the existing pier; then, a bottom seal is formed by pouring concrete in the cofferdam, and a water-proof cofferdam is formed by the bottom seal, the casing, and the side wall of the existing pier; finally, a new pier is formed by constructing steel bars and pouring concrete in the water-proof cofferdam. Since the water-proof cofferdam is formed by the bottom seal, the casing, and the side wall of the existing pier, the poured new pier is connected to the existing pier as a whole, that is, the new pier and the existing pier are spliced ​​together. Thus, a standardized and feasible new cofferdam erection method and a new pier and an existing pier splicing method are provided, which realize the splicing of the new pier and the existing pier, so as to reinforce the existing pier and thereby achieve the purpose of improving the bearing capacity of the bridge.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater engineering, and in particular to a splicing construction method for a deep-water bridge pier. Background Art

[0002] A pile foundation is a deep foundation that connects the tops of several piles together through a cap, allowing them to jointly bear dynamic and static loads. A pile foundation is a vertical or inclined foundation structure set into the soil. Its function is to penetrate soft, highly compressible soil or water layers and transfer the load borne by the piles to a harder, denser, or less compressible bearing layer of the foundation. A cap is a reinforced concrete platform installed on top of the piles, connecting the tops of the piles. Columns or piers are then built on the cap to form a complete bridge load transmission system.

[0003] During the construction of bridge foundations, when the design elevation of the bridge pier is below the surface water level, in order to ensure the smooth progress of the construction, the cofferdam method is usually used to isolate the water within the range of the bridge pier, so that the bridge pier can be constructed under waterless conditions. When constructing piers in deep water areas, the steel cofferdam casing process is usually used for water isolation. The design of the steel cofferdam casing is not affected by other structures. It only needs to consider the structural dimensions of the bridge pier. It is often designed to be fully enclosed with four sides, a bottom plate surface and bottom concrete. The construction steps are to set a lowering device on the completed pile casing. The bottom of the lowering device is connected to the casing bottom plate. The bottom plate size is larger than the pier plane size. The steel casing is installed on the bottom plate and sealed. After the casing is lowered to the design elevation using the lowering device, the bottom concrete is poured. After the concrete strength reaches the design requirements, the water in the steel casing is drained. After the water is pumped out, the pier reinforcement installation, concrete pouring and other construction are carried out. Finally, the steel casing is removed.

[0004] However, with the improvement of bridge construction standards and the continuous maturity of construction technology, the bearing capacity and anti-ship collision capability of some bridge structures built in the early days can no longer meet actual needs, posing a major safety hazard to the normal use of bridges. Some bridge structures need to be strengthened to ensure the safety of normal use of bridge structures. Strengthening measures such as increasing the number of piles and increasing the cross-sectional size of the pedestals are usually adopted. In order to enable the newly built pedestals to share the load borne by the existing pedestals, the newly built pedestals and the existing pedestals need to be spliced. However, for bridges built in deep water areas, the splicing between the newly built pedestals and the existing pedestals will be restricted by the deep water conditions and the existing pedestals, resulting in the cofferdam erection for the construction of the new pedestals being limited, and the cofferdam casing cannot be designed as a closed structure on four sides, that is, the existing deep-water bridge pedestal construction process cannot be directly applied, resulting in the difficulty of splicing bridge pedestals in deep water areas, and thus the purpose of improving the bearing capacity of bridges cannot be achieved. Summary of the Invention

[0005] The purpose of the present invention is to provide a splicing construction method for deep-water bridge piers, so as to solve the problem in the prior art that the existing deep-water bridge pier construction process cannot be directly applied when splicing a new pier with an existing pier, resulting in the difficulty in achieving the purpose of improving the bearing capacity of the bridge.

[0006] In order to achieve the above object, the present invention provides a splicing construction method for a deep-water bridge cap, which comprises the following steps:

[0007] Step S1: construct a new pile foundation on one side of the existing bridge according to the design drawings;

[0008] Step S2: forming an assembly platform on the outer periphery of the pile casing of the newly added pile foundation, and assembling the prefabricated bottom plate and the casing on the assembly platform to form a cofferdam;

[0009] The casing is provided with an opening and a tensioning system for tightening the opening at one end close to the existing foundation; a water stop is installed on the inner side of the opening;

[0010] Step S3, lowering the cofferdam to the designed elevation;

[0011] Closing the gap between the prefabricated bottom plate and the remaining bottom plate of the existing platform; tightening the opening of the casing using a tensioning system and pressing the water stop against the side wall of the existing platform;

[0012] Step S4: pouring bottom seal concrete in the cofferdam to form a bottom seal, wherein the bottom seal, the casing and the side wall of the existing cap are enclosed to form a water-proof cofferdam;

[0013] Step S5: constructing steel bars in the water-proof cofferdam and pouring concrete to form a new foundation.

[0014] Furthermore, in step S2, an assembly platform is formed on the outer periphery of the pile casing of the newly added pile foundation, and a prefabricated bottom plate and a casing are assembled on the assembly platform to form a cofferdam. The casing is provided with an opening and a tensioning system for tightening the opening at one end close to the existing pile cap, and a water stop is installed on the inner side of the opening, specifically comprising:

[0015] Step S2-1: Welding temporary brackets on the outer periphery of the pile casing of the newly added pile foundation at the designed elevation of the assembly platform to form an assembly platform;

[0016] Step S2-2, placing a prefabricated base plate on the assembly platform, and connecting and fixing the prefabricated base plate to the temporary corbel;

[0017] Step S2-3: placing a plurality of casing side molds connected end to end along the edges of the prefabricated bottom plate that are not opposite to the existing bearing platform above the prefabricated bottom plate, and sequentially connecting the plurality of casing side molds to form a casing with the opening;

[0018] Step S2-4, installing a tensioning system for tightening the opening at one end of the casing close to the existing foundation;

[0019] Step S2-5, connecting and fixing the prefabricated bottom plate and the casing to form a cofferdam;

[0020] Step S2-6: Install a water stop on the inner side of the opening.

[0021] Furthermore, in step S2-2, a prefabricated base plate is placed on the assembly platform and connected and fixed to the temporary corbel, specifically comprising:

[0022] S2-2-1. Place bottom load-bearing beams on both sides of the newly added pile foundation along the second direction, and place the bottom load-bearing beams along the first direction; connect and fix the bottom load-bearing beams to the temporary corbels;

[0023] The first direction and the second direction are perpendicular to each other in a horizontal plane, and the newly added pile foundation is located on one side of the existing foundation in the first direction;

[0024] S2-2-2. Sleeve the prefabricated bottom plate on the outer periphery of the pile casing of the newly added pile foundation and place it horizontally above the bottom load-bearing beam; connect the prefabricated bottom plate to the bottom load-bearing beam.

[0025] Furthermore, in step S2-4, a tensioning system for tightening the opening is installed at one end of the casing close to the existing foundation, specifically comprising:

[0026] S2-4-1. Installing a tensioning jack and a tensioning conversion support connected to each other on one side surface of the casing in the second direction;

[0027] S2-4-2, placing the stretched and finished rolled threaded steel bar along the second direction, and connecting and fixing one end of the stretched and finished rolled threaded steel bar to the other side surface of the casing in the second direction;

[0028] S2-4-3. Pass the other end of the tensioned finished rolled threaded steel bar through the tensioning jack and the tensioning conversion support to form a tensioning system.

[0029] Furthermore, between step S2-3 and step S2-4, the following steps are further included:

[0030] Placing a plurality of casing ring beams connected in sequence on the inner side of the casing along the extending direction of the plurality of casing side molds; connecting and fixing the plurality of casing ring beams to the inner side of the casing;

[0031] An inner support is placed toward the inner side of the casing along the second direction, and both ends of the inner support are connected and fixed to the casing ring beam.

[0032] Furthermore, in step S3, the cofferdam is lowered to the designed elevation; the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pile cap is closed; and the opening of the casing is tightened using a tensioning system and the water stop is pressed against the side wall of the existing pile cap, specifically including:

[0033] S3-1, installing a lowering jack and a lowering conversion support on the top of the pile casing of the newly added pile foundation;

[0034] S3-2, inserting the lowered fine-rolled threaded steel bars into the lowering jacks and the lowering conversion supports to form a lowering system;

[0035] S3-3, connecting and fixing the lower end of the lowered fine-rolled threaded steel bar to the prefabricated bottom plate;

[0036] S3-4, dismantle the assembly platform and lower the cofferdam to the designed elevation;

[0037] S3-5, closing the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pile cap;

[0038] S3-6. Use a tensioning system to tighten the opening of the casing and squeeze the water stop against the side wall of the existing foundation.

[0039] Furthermore, in step S3-5, the gap between the prefabricated bottom plate and the remaining bottom plate of the existing foundation is closed by:

[0040] A steel template is laid underwater along the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pedestal, and both ends of the steel template are connected to the prefabricated bottom plate and the remaining bottom plate of the existing pedestal respectively.

[0041] Furthermore, in step S4, bottom seal concrete is poured in the water-proof cofferdam to form a bottom seal, and the bottom seal, the casing, and the side wall of the existing foundation are enclosed to form a water-proof cofferdam, which specifically includes:

[0042] S4-1, performing a first pouring in the water-proof cofferdam, and ensuring that the top surface formed by the first pouring is lower than the design elevation of the bottom cover;

[0043] S4-2, draining the water in the water-proof cofferdam;

[0044] S4-3. Weld and fix the brackets on the outer periphery of the pile casing of each newly added pile foundation above the top surface formed by the first pouring;

[0045] S4-4, anchoring the upper end of the lowered fine-rolled threaded steel bar to the fixed corbel;

[0046] S4-5. Perform a second pouring to form a bottom seal, wherein the bottom seal, the casing and the side wall of the existing foundation are combined to form a water-proof cofferdam.

[0047] Furthermore, in step S3-1, the step of installing a lowering jack and a lowering conversion support on the top of the pile casing of the newly added pile foundation specifically includes:

[0048] S3-1-1. Leveling the upper surface of the pile casing of the newly added pile foundation, and welding and fixing an upper load-bearing beam on the upper surface of the pile casing of the newly added pile foundation;

[0049] S3-1-2. Install and fix the lowering jack and the lowering conversion support on the upper load-bearing beam.

[0050] The splicing construction method of a deep-water bridge pier provided by the present invention has the following advantages compared with the prior art:

[0051] New pile foundations are formed through construction to form an assembly platform on the new pile foundations, and the prefabricated bottom plate and the casing are assembled to form a cofferdam; an opening is set at one end of the casing close to the existing pedestal so that the casing can be connected to the side wall of the existing pedestal through the opening, and the opening is tightened by the tensioning system so that the water stop is squeezed close to the side wall of the existing pedestal to achieve the purpose of closed water stopping; then a bottom seal is formed by pouring concrete in the cofferdam, and a water-proof cofferdam is formed by the bottom seal, the casing and the side wall of the existing pedestal, so that the water-proof cofferdam can isolate water from the new pile foundation; finally, a new pedestal is formed by constructing steel bars and pouring concrete in the water-proof cofferdam. Since the water-proof cofferdam is formed by the bottom seal, the casing and the side wall of the existing pedestal, the new pedestal formed by pouring is connected to the existing pedestal as a whole, that is, the splicing of the new pedestal and the existing pedestal is achieved. This provides a standardized and feasible method for erecting a new cofferdam and a method for splicing a new pier with an existing one, thereby realizing the splicing of a new pier with an existing one to reinforce the existing pier and thus achieve the purpose of improving the bearing capacity of the bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of a method for splicing and constructing a deep-water bridge cap according to an embodiment of the present invention;

[0053] Figure 2 1 is a schematic elevation diagram of the connection between a newly built foundation cap and an existing foundation cap in an embodiment of the present invention;

[0054] Figure 3 is a schematic plan view of the connection between a newly built foundation cap and an existing foundation cap in an embodiment of the present invention;

[0055] Figure 4 yes Figure 2 Schematic diagram of the medium AA perspective;

[0056] Figure 5 yes Figure 4 A magnified schematic diagram of area A in the middle;

[0057] Figure 6 yes Figure 3 Schematic diagram of the middle BB perspective;

[0058] Figure 7 yes Figure 6 A magnified schematic diagram of area B in the middle;

[0059] Figure 8 yes Figure 6 Enlarged schematic diagram of the middle C area;

[0060] Figure 9 It is a plan view of a prefabricated base plate in an embodiment of the present invention.

[0061] In the figure, 1. New pile foundation; 11. Temporary corbel; 12. Upper load-bearing beam; 21. Bottom load-bearing beam; 22. Precast base plate; 220. Through hole; 221. Single plate; 3. Lowering system; 31. Lowering jack; 32. Lowering fine-rolled threaded steel bar; 33. Lowering conversion support; 4. Casing; 40. Opening; 41. Casing side form; 42. Casing ring beam; 43. Inner support; 44. Water stop; 5. Tensioning system; 51. Tensioning jack; 52. Tensioning fine-rolled threaded steel bar; 53. Tensioning conversion support; 6. Steel formwork; 10. Bottom cover; 100. New pier; 200. Existing pier. DETAILED DESCRIPTION

[0062] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0063] like Figures 1 to 9 As shown, a splicing construction method of a deep-water bridge pier according to an embodiment of the present invention includes the following steps:

[0064] Step S1: construct a new pile foundation 1 on one side of the existing bridge according to the design drawings;

[0065] Step S2: forming an assembly platform on the outer periphery of the pile casing of the newly added pile foundation 1, and assembling the prefabricated bottom plate 22 and the casing 4 on the assembly platform to form a cofferdam;

[0066] The casing 4 is provided with an opening 40 and a tensioning system 5 for tightening the opening 40 at one end close to the existing support 200; a water stop 44 is installed inside the opening 40;

[0067] Step S3, lowering the cofferdam to the designed elevation;

[0068] Close the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing platform 200; use the tensioning system 5 to tighten the opening 40 of the casing 4 and press the water stop against the side wall of the existing platform 200;

[0069] Step S4: pouring bottom seal concrete in the cofferdam to form a bottom seal 10, and the bottom seal, the casing and the side wall of the existing foundation 200 are combined to form a water-proof cofferdam;

[0070] Step S5: constructing steel bars and pouring concrete in the water-proof cofferdam to form a new foundation 100.

[0071] Based on the above technical solution, a new pile foundation 1 is formed through construction to form an assembly platform on the new pile foundation 1, and the prefabricated bottom plate 22 and the casing 4 are assembled to form a cofferdam; an opening 40 is provided at one end of the casing 4 close to the existing pedestal 200 so that the casing 4 can be connected to the side wall of the existing pedestal 200 through the opening 40, and the opening 40 is tightened by the tensioning system 5 so that the water stop is squeezed and pressed against the side wall of the existing pedestal 200 to achieve the purpose of closed water stopping; and then the water stop is closed. By pouring bottom concrete in the cofferdam to form a bottom seal, the bottom seal, the casing 4 and the side walls of the existing pedestal 200 form a water-proof cofferdam, so that the water-proof cofferdam can isolate the water from the newly added pile foundation 1; finally, by constructing steel bars and pouring concrete in the water-proof cofferdam to form a new pedestal, since the water-proof cofferdam is formed by the bottom seal, the casing 4 and the side walls of the existing pedestal 200, the new pedestal formed by pouring is connected to the existing pedestal as a whole, that is, the new pedestal and the existing pedestal are spliced ​​together. This provides a standardized and feasible method for erecting a new cofferdam and a method for splicing a new pedestal with an existing pedestal, so as to realize the splicing of a new pedestal with an existing pedestal, so as to reinforce the existing pedestal, thereby achieving the purpose of improving the bearing capacity of the bridge.

[0072] Further, if Figure 2 、 Figure 4 and Figure 5 As shown, in step S2, an assembly platform is formed on the outer periphery of the pile casing of the newly added pile foundation 1, and a prefabricated bottom plate 22 and a casing 4 are assembled on the assembly platform to form a cofferdam. The casing 4 is provided with an opening 40 and a tensioning system 5 for tightening the opening at one end close to the existing cap 200, and a water stop is installed on the inner side of the opening, specifically including:

[0073] Step S2-1: Welding a temporary bracket 11 on the outer periphery of the pile casing of the newly added pile foundation 1 at the designed elevation of the assembly platform to form an assembly platform;

[0074] Step S2-2: placing the prefabricated bottom plate 22 on the assembly platform, and connecting and fixing the prefabricated bottom plate 22 to the temporary corbel 11;

[0075] Step S2-3: placing a plurality of casing side molds 41 connected end to end above the prefabricated bottom plate 22 along the edges of the prefabricated bottom plate 22 that are not opposite to the existing bearing platform 200, and sequentially connecting the plurality of casing side molds 41 to form a casing 4 having the opening 40;

[0076] Step S2-4: Installing a tensioning system 5 for tightening the opening 40 at one end of the casing 4 close to the existing support 200;

[0077] Step S2-5, connecting and fixing the prefabricated bottom plate 22 and the casing 4 to form a cofferdam;

[0078] Step S2 - 6 : Install a water stopper 44 on the inner side of the opening 40 .

[0079] It can be understood that, through step S2-1, the temporary corbel 11 is welded to realize the construction of the splicing platform, and the temporary corbel 11 is easy to cut off from the pile casing of the newly added pile foundation 1, so as to facilitate the subsequent dismantling of the assembled platform; through steps S2-3 and S2-4, the casing 4 is specifically provided with an opening 40 at one end close to the existing foundation 200 and a tensioning system 5, so that construction personnel can perform standardized construction according to the steps, thereby improving construction efficiency.

[0080] Preferably, in this embodiment, the waterstop member 44 is a waterstop rubber strip, which has elastic deformation properties and is easy to obtain. When the tensioning system 5 tightens the opening 40, the waterstop rubber strip located on the inner side of the opening 40 is squeezed between the inner wall of the sleeve 4 and the side wall of the existing support platform 200, thereby achieving the purpose of sealing and waterstopping between the sleeve 4 and the side wall of the existing support platform 200; in some other embodiments, different waterstop members can be selected according to different needs, which will not be elaborated here.

[0081] Further, if Figure 3 and Figure 6 As shown, in step S2-2, the prefabricated bottom plate 22 is placed on the assembly platform, and the prefabricated bottom plate 22 is connected and fixed to the temporary corbel 11, which specifically includes:

[0082] S2-2-1. Place bottom bearing beams 21 on both sides of the pile casing of the newly added pile foundation 1 along the second direction Y, and place the bottom bearing beams 21 along the first direction X; connect and fix the bottom bearing beams 21 to the temporary corbels 11;

[0083] The first direction X and the second direction Y are perpendicular to each other on a horizontal plane, and the newly added pile foundation 1 is located on one side of the existing foundation 200 in the first direction X;

[0084] S2-2-2. Sleeve the prefabricated bottom plate 22 on the outer periphery of the pile casing of the newly added pile foundation 1 and place it horizontally above the bottom load-bearing beam 21; connect the prefabricated bottom plate 22 to the bottom load-bearing beam 21.

[0085] Through steps S2-2-1 and S2-2-2, the bottom load-bearing beam 21 is first connected and fixed to the temporary corbel 11, and then the prefabricated bottom plate 22 is placed above the bottom load-bearing beam 21, and the prefabricated bottom plate 22 and the bottom load-bearing beam 21 are connected to improve the reliability and strength of the prefabricated bottom plate 22; and facilitate the connection between the prefabricated bottom plate 22 and the temporary corbel 11 and the transfer of load.

[0086] Preferably, in order to facilitate uniform force transmission to the pile casing of the newly added pile foundation 1, four temporary corbels 11 are welded and fixed at uniform intervals on the outer periphery of the pile casing of each newly added pile foundation 1; each temporary corbel 11 is arranged at a certain angle to the first direction X and the second direction Y.

[0087] Preferably, if Figure 9 As shown, in order to reduce the difficulty of lifting and production processing of lifting machinery and facilitate the lowering of the prefabricated base plate 22 and the casing 4, the prefabricated base plate 22 includes multiple groups of base plate units, each group of base plate units includes a pair of single plates 221 symmetrically arranged along the first direction X, and a pair of single plates 221 are provided with semicircular holes at opposite ends, and the two semicircular holes enclose the through hole 220.

[0088] Further, if Figure 4 and Figure 5 As shown, in step S2-4, a tensioning system 5 for tightening the opening 40 is installed at one end of the casing 4 close to the existing support 200, specifically comprising:

[0089] S2-4-1, installing a tensioning jack 51 and a tensioning conversion support 53 connected to each other on one side surface of the casing 4 in the second direction Y;

[0090] S2-4-2, placing the stretched and finished rolled threaded steel bar 52 along the second direction Y, and connecting and fixing one end thereof to the other side surface of the casing 4 in the second direction Y;

[0091] S2-4-3. Pass the other end of the tensioned finished rolled threaded steel bar 52 through the tensioning jack 51 and the tensioning conversion support 53 to form a tensioning system 5.

[0092] A tensioning system 5 is formed by a tensioning jack 51, a tensioning fine-rolled threaded steel bar 52 and a tensioning conversion support 53. Through the mutual cooperation of the tensioning jack 51, the tensioning fine-rolled threaded steel bar 52 and the tensioning conversion support 53, the opening 40 can be tightened by pulling the unfixed end of the tensioning fine-rolled threaded steel bar 52.

[0093] Further, if Figure 4 and Figure 5 As shown, between step S2-3 and step S2-4, the following is also included:

[0094] Along the extending direction of the plurality of casing side molds 41, a plurality of casing ring beams 42 are sequentially placed on the inner side of the casing 4; the plurality of casing ring beams 42 are connected and fixed to the inner side of the casing;

[0095] An inner support 43 is placed toward the inner side of the casing along the second direction Y, and both ends of the inner support 43 are connected and fixed to the casing ring beam 42 .

[0096] It can be understood that by placing multiple casing ring beams 42 connected in sequence on the inner side of the multiple casing side molds 41, the overall strength of the casing 4 can be improved; and by placing internal supports along the second direction Y, when the tensioning system 5 tightens the opening 40, the casing 4 except the opening position can maintain its original shape without deformation under the support of the internal supports 43.

[0097] Further, if Figure 3 、 Figure 6 and Figure 7 As shown, in step S3, the cofferdam is lowered to the designed elevation; the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing platform 200 is closed; the opening 40 of the casing 4 is tightened using the tensioning system 5 and the water stop 44 is pressed against the side wall of the existing platform 200, which specifically includes:

[0098] S3-1, installing a lowering jack 31 and a lowering conversion support 33 on the top of the pile casing of the newly added pile foundation 1;

[0099] S3-2, inserting the lowered fine-rolled threaded steel bar 32 into the lowering jack 31 and the lowering conversion support 33 to form a lowering system 3;

[0100] S3-3, connecting and fixing the lower end of the lowered fine-rolled threaded steel bar 32 to the prefabricated bottom plate 22;

[0101] S3-4, dismantle the assembly platform and lower the cofferdam to the designed elevation;

[0102] S3-5, closing the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing platform 200;

[0103] S3-6. Use the tensioning system 5 to tighten the opening 40 of the casing 4 and press the water stop 44 against the side wall of the existing foundation 200.

[0104] It can be understood that, by lowering the jack 31 , lowering the finished rolled threaded steel bar 32 and lowering the conversion support 33 , a simple and easy-to-use lowering system 3 is formed, so as to facilitate lowering the cofferdam to the designed elevation.

[0105] Further, if Figure 3 、 Figure 6 and Figure 8As shown, in order to specifically realize the closing of the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing platform 200; the closing of the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing platform 200 in step S3-5 is specifically as follows:

[0106] A steel template 6 is laid underwater along the gap between the prefabricated bottom plate 22 and the remaining bottom plate of the existing foundation 200 , and both ends of the steel template 6 are connected to the prefabricated bottom plate 22 and the remaining bottom plate of the existing foundation 200 .

[0107] Furthermore, in step S4, bottom seal concrete is poured in the water-proof cofferdam to form a bottom seal, and the bottom seal, the casing, and the side wall of the existing foundation are enclosed to form a water-proof cofferdam, which specifically includes:

[0108] S4-1, performing a first pouring in the water-proof cofferdam, and ensuring that the top surface formed by the first pouring is lower than the design elevation of the bottom cover;

[0109] S4-2, draining the water in the water-proof cofferdam;

[0110] S4-3, welding and fixing a corbel on the outer periphery of the pile casing of each newly added pile foundation 1 above the top surface formed by the first pouring;

[0111] S4-4, anchoring the upper end of the lowered fine-rolled threaded steel bar 32 to the fixed corbel;

[0112] S4-5. Perform a second pouring to form a bottom seal 10. The bottom seal, the casing and the side wall of the existing foundation are combined to form a water-proof cofferdam.

[0113] It is understandable that since the cofferdam is lowered by connecting to the lowered fine-rolled threaded steel bar 32 during construction, the lowered fine-rolled threaded steel bar 32 is usually pulled by a power machine, but the power machine needs to be removed after completion, so the movable end of the lowered fine-rolled threaded steel bar 32 needs to be anchored to the existing structure. To achieve the anchoring of the lowered fine-rolled threaded steel bar 32, a fixed bracket is welded to the outer periphery of the pile casing of the newly added pile foundation 1, and the upper end of the lowered fine-rolled threaded steel bar 32 is anchored to the fixed bracket; then, through secondary pouring, the anchor connection position of the lowered fine-rolled threaded steel bar 32 and the fixed bracket is buried in the bottom cover 10 to ensure that the load is effectively transferred to the bottom cover 10 and the newly added pile foundation 1.

[0114] Preferably, in this embodiment, the top surface height formed by the first pouring is 30 mm lower than the design elevation of the bottom cover, so that the fixed corbel can be completely buried in the bottom cover; in some other embodiments, the top surface height formed by the first pouring can be determined according to actual needs and is not specifically limited here.

[0115] Further, if Figure 3 、 Figure 6 and Figure 8 As shown, since it is not convenient to place fixed objects on the top of the pile casing of the newly added pile foundation 1, in order to facilitate the installation and fixing of the lowering jack 31 and the lowering conversion support 33; the step S3-1 of installing the lowering jack 31 and the lowering conversion support 33 on the top of the pile casing of the newly added pile foundation 1 specifically includes:

[0116] S3-1-1, leveling the upper surface of the pile casing of the newly added pile foundation 1, and welding and fixing the upper bearing beam 12 on the upper surface of the pile casing of the newly added pile foundation;

[0117] S3-1-2. Install and fix the lowering jack 31 and the lowering conversion support 33 on the upper load-bearing beam 12.

[0118] Preferably, in order to specifically regulate the construction process of the newly built cap 100, the step S5 of constructing steel bars and pouring concrete in the water-proof cofferdam to form the newly built cap specifically includes:

[0119] S5-1, constructing and installing steel bars and embedded parts in the water-proof cofferdam;

[0120] S5-2, drilling holes, planting reinforcement and roughening the surface of the existing cap forming the water-proof cofferdam;

[0121] S5-3. Connect the steel bars in the water-proof cofferdam with the embedded steel bars of the existing foundation pile;

[0122] S5-4, pouring concrete to form a new foundation 100.

[0123] Preferably, the splicing construction method of the deep-water bridge cap further comprises:

[0124] Step S6: dismantle the casing side formwork 41 underwater, and carry out the subsequent construction of the auxiliary structures of the new foundation 100.

[0125] In summary, the embodiment of the present invention provides a method for splicing and constructing a deep-water bridge pier, which forms a new pile foundation 1 through construction to form an assembly platform on the new pile foundation 1, and assembles the prefabricated bottom plate 22 and the casing 4 to form a cofferdam; by providing an opening 40 at one end of the casing 4 close to the existing pier 200, the casing 4 can be connected to the side wall of the existing pier 200 through the opening 40, and by tightening the opening 40 through the tensioning system 5, the water stop is squeezed and pressed against the side wall of the existing pier 200 to achieve the cofferdam. The purpose of closing and stopping water is achieved; then a bottom seal is formed by pouring concrete in the cofferdam, and a water-proof cofferdam is formed by the bottom seal, the casing 4 and the side wall of the existing pedestal 200, so that the water-proof cofferdam can isolate the water from the newly added pile foundation 1; finally, a new pedestal is formed by constructing steel bars and pouring concrete in the water-proof cofferdam. Since the water-proof cofferdam is formed by the bottom seal, the casing 4 and the side wall of the existing pedestal 200, the new pedestal formed by pouring is connected to the existing pedestal as a whole, that is, the new pedestal and the existing pedestal are spliced ​​together. This provides a standardized and feasible method for erecting a new cofferdam and a method for splicing a new pedestal with an existing pedestal, so as to realize the splicing of a new pedestal with an existing pedestal, so as to reinforce the existing pedestal, thereby achieving the purpose of improving the bearing capacity of the bridge.

[0126] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A splicing construction method for a deep-water bridge cap, characterized in that: The following steps are involved: Step S1: construct a new pile foundation on one side of the existing bridge according to the design drawings; Step S2: forming an assembly platform on the outer periphery of the pile casing of the newly added pile foundation, and assembling the prefabricated bottom plate and the casing on the assembly platform to form a cofferdam; The casing is provided with an opening and a tensioning system for tightening the opening at one end close to the existing foundation; a water stop is installed on the inner side of the opening; Step S3, lowering the cofferdam to the designed elevation; Closing the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pile cap; The opening of the casing is tightened using a tensioning system and the water stop is pressed against the side wall of the existing pile cap, specifically including: S3-1, installing a lowering jack and a lowering conversion support on the top of the pile casing of the newly added pile foundation; S3-2, inserting the lowered fine-rolled threaded steel bars into the lowering jacks and the lowering conversion supports to form a lowering system; S3-3, connecting and fixing the lower end of the lowered fine-rolled threaded steel bar to the prefabricated bottom plate; S3-4, dismantle the assembly platform and lower the cofferdam to the designed elevation; S3-5, closing the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pile cap; S3-6, using a tensioning system to tighten the opening of the casing and squeeze the water stop against the side wall of the existing platform; Step S4, pouring bottom seal concrete in the cofferdam to form a bottom seal, wherein the bottom seal, the casing and the side wall of the existing foundation are combined to form a water-proof cofferdam, specifically comprising: S4-1, performing a first pouring in the cofferdam, and ensuring that the top surface formed by the first pouring is lower than the design elevation of the bottom cover; S4-2, draining the water in the cofferdam; S4-3. Weld and fix the brackets on the outer periphery of the pile casing of each newly added pile foundation above the top surface formed by the first pouring; S4-4, anchoring the upper end of the lowered fine-rolled threaded steel bar to the fixed corbel; S4-5, performing a second pouring to form a bottom seal, wherein the bottom seal, the casing, and the side wall of the existing cap form a water-proof cofferdam; Step S5: constructing steel bars in the water-proof cofferdam and pouring concrete to form a new foundation.

2. The method for splicing and constructing a deepwater bridge cap according to claim 1, characterized in that: In step S2, an assembly platform is formed on the outer periphery of the pile casing of the newly added pile foundation, and a prefabricated bottom plate and a casing are assembled on the assembly platform to form a cofferdam. The casing is provided with an opening and a tensioning system for tightening the opening at one end close to the existing foundation cap, and a water stop is installed on the inner side of the opening, specifically comprising: Step S2-1: Welding temporary brackets on the outer periphery of the pile casing of the newly added pile foundation at the designed elevation of the assembly platform to form an assembly platform; Step S2-2, placing a prefabricated base plate on the assembly platform, and connecting and fixing the prefabricated base plate to the temporary corbel; Step S2-3: placing a plurality of casing side molds connected end to end along the edges of the prefabricated bottom plate that are not opposite to the existing bearing platform above the prefabricated bottom plate, and sequentially connecting the plurality of casing side molds to form a casing with the opening; Step S2-4, installing a tensioning system for tightening the opening at one end of the casing close to the existing foundation; Step S2-5, connecting and fixing the prefabricated bottom plate and the casing to form a cofferdam; Step S2-6: Install a water stop on the inner side of the opening.

3. The method for splicing and constructing a deepwater bridge cap according to claim 2, characterized in that: In step S2-2, a prefabricated base plate is placed on the assembly platform and connected and fixed to the temporary corbel, specifically comprising: S2-2-1. Place bottom load-bearing beams on both sides of the newly added pile foundation along the second direction, and place the bottom load-bearing beams along the first direction; connect and fix the bottom load-bearing beams to the temporary corbels; The first direction and the second direction are perpendicular to each other in a horizontal plane, and the newly added pile foundation is located on one side of the existing foundation in the first direction; S2-2-2. Sleeve the prefabricated bottom plate on the outer periphery of the pile casing of the newly added pile foundation and place it horizontally above the bottom load-bearing beam; connect the prefabricated bottom plate to the bottom load-bearing beam.

4. The method for splicing and constructing a deepwater bridge cap according to claim 3, characterized in that: In step S2-4, a tensioning system for tightening the opening is installed at one end of the casing close to the existing foundation, specifically comprising: S2-4-1. Installing a tensioning jack and a tensioning conversion support connected to each other on one side surface of the casing in the second direction; S2-4-2, placing the stretched and finished rolled threaded steel bar along the second direction, and connecting and fixing one end of the stretched and finished rolled threaded steel bar to the other side surface of the casing in the second direction; S2-4-3. Pass the other end of the tensioned finished rolled threaded steel bar through the tensioning jack and the tensioning conversion support to form a tensioning system.

5. The method for splicing and constructing a deepwater bridge cap according to claim 3, characterized in that: The steps S2-3 and S2-4 further include: Placing a plurality of casing ring beams connected in sequence on the inner side of the casing along the extending direction of the plurality of casing side molds; connecting and fixing the plurality of casing ring beams to the inner side of the casing; An inner support is placed toward the inner side of the casing along the second direction, and both ends of the inner support are connected and fixed to the casing ring beam.

6. The method for splicing and constructing a deepwater bridge cap according to claim 1, characterized in that: In step S3-5, the gap between the prefabricated bottom plate and the remaining bottom plate of the existing platform is closed by: A steel template is laid underwater along the gap between the prefabricated bottom plate and the remaining bottom plate of the existing pedestal, and both ends of the steel template are connected to the prefabricated bottom plate and the remaining bottom plate of the existing pedestal respectively.

7. The method for splicing and constructing a deepwater bridge cap according to claim 1, characterized in that: The step S3-1 includes installing a lowering jack and a lowering conversion support on the top of the pile casing of the newly added pile foundation, specifically comprising: S3-1-1, leveling the upper surface of the pile casing of the newly added pile foundation, and welding and fixing an upper load-bearing beam on the upper surface of the pile casing of the newly added pile foundation; S3-1-2. Install and fix the lowering jack and the lowering conversion support on the upper load-bearing beam.

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