Beam construction formwork connecting system and method suitable for water level fluctuation environment

Abstract

The application discloses a concrete beam construction bottom die connecting system suitable for water level fluctuation environment, which comprises a bottom die main beam, at least two groups of L-shaped screw rods, straight connecting steel bars, at least two anchor steel pipes and fixing steel bars; two bottom die main beams are symmetrically arranged on both sides of a pile foundation, bolt holes are formed in the upper flange and the lower flange of each bottom die main beam respectively; both ends of the L-shaped screw rod are provided with external threads, the horizontal section of the L-shaped screw rod is placed on the top surface of a pier column or a bored pile, and the vertical section of the L-shaped screw rod penetrates through the bolt hole of the bottom die main beam; one end of the straight connecting steel bar is detachably connected with the end of the horizontal section of the first group of L-shaped screw rods and the end of the horizontal section of the second group of L-shaped screw rods respectively; the anchor steel pipe is embedded in the concrete at the top of the pile foundation, the anchor steel pipe is sleeved on the anchor steel bar of the pile foundation and is fixedly connected with the anchor steel bar; and the fixing steel bar is tied and connected with the straight connecting steel bar and the anchor steel pipe respectively.

Description

Technical Field

[0001] This invention relates to the field of bottom formwork connection in beam construction. More specifically, this invention relates to a bottom formwork connection system and method for beam construction that adapts to environments with fluctuating water levels. Background Technology

[0002] Concrete beams are commonly found in the beams of high-pile wharves and as connecting beams between bridge piers. The design elevation of the bottom of the beam is usually lower than the design high water level (0.3 to 0.8 meters for river ports and 0 to 1 meter for sea ports). In the current environment of large water level fluctuations, there are two types of bottom formwork connection systems for the construction of concrete beams.

[0003] The first method uses clamps or steel brackets as support points, on which the bottom formwork, main beam, timber distribution beams, formwork, and other components are erected. The clamps and brackets are generally over 400mm high, and the steel main beams are over 250mm high. Considering construction space, the water level should be 1.5 meters below the top of the pier or pile during the clamp installation or bracket welding stage.

[0004] The second method is to use steel or earthen cofferdams to create a dry construction environment for construction. This method has a long construction period and very high construction costs, so it is rarely used.

[0005] River levels in China tend to rise easily during the summer. Coastal areas of China generally experience semi-diurnal tides, with prolonged periods of high water levels and significant tidal ranges in some areas. When the water level is too close to, or even exceeds, the top surface of the piers or piles, the bottom formwork support system cannot be constructed, resulting in idle work or extremely low efficiency. Summary of the Invention

[0006] In order to achieve these objectives and other advantages according to the present invention, in one aspect, a preferred embodiment of the present invention provides a bottom formwork connection system for concrete beam construction adapted to water level fluctuation environments, including a bottom formwork main beam, at least two sets of L-shaped bolts, straight connecting steel bars, at least two anchoring steel pipes, and fixing steel bars; The two bottom formwork main beams are symmetrically arranged on both sides of the pile foundation, and bolt holes are opened on the upper and lower flanges of each bottom formwork main beam; Both ends of the L-shaped screw are provided with external threads. The horizontal section of the L-shaped screw rests on the top surface of the pier or bored pile, and the vertical section of the L-shaped screw passes through the bolt holes of the bottom formwork main beam. One end of the straight connecting steel bar is detachably connected to the horizontal end of the first group of L-shaped screws and the horizontal end of the second group of L-shaped screws, respectively; The anchoring steel pipe is embedded in the concrete at the top of the pile foundation, and the anchoring steel pipe is sleeved on the anchoring steel bar of the pile foundation and fixedly connected to the anchoring steel bar. The fixing reinforcing bars are respectively tied to the direct connecting reinforcing bars and the anchoring steel pipe.

[0007] Preferably, the assembly further includes a nut assembly comprising an upper nut and a lower nut. The upper nut is screwed onto the vertical section of the L-shaped screw and is located above the upper flange of the bottom mold main beam. The lower nut is screwed onto the vertical section of the L-shaped screw and is located below the lower flange of the bottom mold main beam. The upper nut and the lower nut together clamp and fix the bottom mold main beam.

[0008] Preferably, both ends of the straight connecting steel bar are provided with external threads, and both ends of the straight connecting steel bar are respectively threaded to one end of the steel bar connector, and the other end of the steel bar connector is threaded to the horizontal end of the L-shaped screw.

[0009] On the other hand, a preferred embodiment of the present invention provides a construction method based on the bottom formwork connection system, comprising the following steps: S1. When binding the pile foundation reinforcement cage, the anchoring steel pipe is sleeved on the anchoring steel bar at the top of the pile foundation reinforcement cage and fixed. The reinforcement cage is lowered and concrete is poured into the reinforcement cage so that the lower part of the anchoring steel pipe is embedded in the concrete. Bolt holes are opened on the upper and lower flanges of the bottom formwork main beam, respectively, and L-shaped threaded rods with external threads at both ends and straight connecting steel bars with external threads at both ends are processed. S2. Hoist the bottom formwork main beam to the top surface of the pile foundation. Insert the vertical section of the first set of L-shaped screws into the upper nut, the bolt hole of the bottom formwork main beam and the lower nut in sequence. Control the elevation of the bottom formwork main beam by adjusting the position of the upper nut on the vertical section of the L-shaped screw. S3. One end of the hand-operated hoist is wrapped around the bottom formwork main beam, and the other end of the hand-operated hoist is hooked onto the anchoring steel pipe. Tighten the hand-operated hoist. S4. Continue to lower the bottom formwork main beam to the elevation of the bottom formwork support part, and at the same time tighten the hand chain hoist. Use the chain hoist to fine adjust the plane position of the main beam so that the L-shaped screw is basically located in the center of the pile foundation. At this time, the first set of L-shaped screws temporarily fixes the bottom formwork main beam. S5. Repeat S2-S4 until the second set of L-shaped screws is used to temporarily fix the other side of the bottom formwork main beam. S6. Connect one end of the straight-connecting rebar to the end of the horizontal section of the first set of L-shaped screw rods using a rebar connector. Figure 7 Connect the other end of the straight-connecting steel bar to the end of the horizontal section of the second set of L-shaped screw rods through a steel bar connector. S7. Use fixed steel bars to tie the straight connecting steel bars to the anchoring steel pipe and remove the hand chain hoist; S8. Install the secondary beams and bottom formwork on the main beam of the bottom formwork. Figure 10 After installing the side formwork, pour the concrete for the crossbeam. S9. After the concrete of the crossbeam reaches the design strength, remove the side formwork, turn the lower nut downward to lower the main beam of the bottom formwork, pull out the bottom formwork and the secondary beam of the bottom formwork, cut off the part of the L-shaped screw that extends out of the bottom of the crossbeam, and lift it away from the main beam of the bottom formwork.

[0010] Preferably, after the main beam is temporarily fixed in step S4, the hand-operated hoist is kept in a slightly tensioned state before step S6 is performed to connect the straight steel bars and tighten the steel bar connector, so that the tension constraint force and the thread tightening force restrain each other and prevent the connection node from loosening and shifting under the disturbance of water flow.

[0011] Preferably, in step S4, when the hand chain hoist is kept in a state of slight tension, the tension constraint force is made greater than the impact force of the water flow in the construction area. The tension constraint force is kept constant throughout the tightening process of the rebar connector, so as to use the tension constraint force to counteract the axial thrust force generated by the thread tightening, and ensure that the straight connection rebar and the L-shaped screw are coaxially connected. After the rebar connector is tightened, continue to keep the hand-operated hoist in a slightly tensioned state and let it stand still, so that the tension constraint force and the thread locking force are coupled to form a stable force system; After the initial settling period, gradually reduce the tension of the chain hoist in stages until it is under slight tension and no further loosening is required.

[0012] Preferably, when the hand chain hoist is kept under slight tension and stationary, the tension force value of the hand chain hoist is recorded first. During the stationary period, the force value is monitored in real time. If the value fluctuates, the hand chain hoist is finely adjusted in time to maintain a constant force. After the stationary period, the tension force is reduced slightly and the connection status between the straight connecting steel bar and the L-shaped screw is observed. After confirming that there is no displacement, the tension force of the hand chain hoist is gradually reduced until the hand chain hoist is in a slightly tensioned state.

[0013] The present invention has at least the following beneficial effects: (1) This invention uses L-shaped screws and nuts as the support points for the main beam of the bottom formwork, eliminating the need for installing steel clamps and welding steel brackets, thus enabling bottom formwork construction to be carried out even at high water levels. Even if the water level is higher than the top of the pier or pile foundation, construction workers can still operate and tighten the bolts underwater. This avoids the downtime of installing the bottom formwork of the crossbeam at high water levels, and in areas with semi-diurnal tides, it can ensure that work can be carried out all day, improving installation efficiency by 50%.

[0014] (2) Compared with the steel clamp scheme, the bottom formwork connection system of the present invention has a lower cost. Both can utilize the short steel bar ends and steel pipe ends of the engineering waste materials to realize waste material utilization and save about 15% of the cost. Compared with the steel cofferdam scheme, the cost of the formwork system formed by the bottom formwork connection system is only 10% to 30% of that.

[0015] (3) In the construction method of this invention, after the crossbeam construction is completed and the side formwork is removed, the L-shaped screw is embedded in the crossbeam concrete. When removing the bottom formwork system, the workers tighten the lower bolts at the bottom of the I-beam downwards, causing the main beam of the I-beam to drop directly by 5 to 10 mm. The wooden formwork and secondary wooden beams of the bottom formwork can then be directly pulled out. Then, the main beam is lifted by a floating crane or crawler crane. The part of the L-shaped screw extending from the bottom of the crossbeam can be directly cut off by the workers from below the crossbeam to above the I-beam, releasing the main beam constraint, and then removed by the floating crane or crawler crane. Only the appearance of the crossbeam needs to be repaired at the cut joint, which is simple and effective. There is no need to add steel gantry, hand-operated hoist, standing platform, or other components to remove the clamps, reducing the cost of demolition construction measures by 20% and improving the efficiency of bottom formwork system demolition by 50%.

[0016] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the construction steps S1 in the construction method of the bottom formwork connection system of the present invention.

[0018] Figure 2 for Figure 1 Sectional view 1-1.

[0019] Figure 3 This is a schematic diagram of the construction steps S2 in the construction method of the bottom formwork connection system of the present invention.

[0020] Figure 4 for Figure 3 Sectional view 1-1.

[0021] Figure 5 This is a schematic diagram of the construction steps S3 in the construction method of the bottom formwork connection system of the present invention.

[0022] Figure 6 for Figure 5 Sectional view 1-1.

[0023] Figure 7 This is a schematic diagram of the construction steps S4 in the construction method of the bottom formwork connection system of the present invention.

[0024] Figure 8 for Figure 7 Sectional view 1-1.

[0025] Figure 9 This is a schematic diagram of the construction steps S5 in the construction method of the bottom formwork connection system of the present invention.

[0026] Figure 10 for Figure 8 Sectional view 1-1.

[0027] Figure 11 This is a schematic diagram of the construction steps S6 in the construction method of the bottom formwork connection system of the present invention.

[0028] Figure 12 for Figure 11 Sectional view 1-1.

[0029] Figure 13 for Figure 6 A partial schematic diagram of point A in the middle.

[0030] Figure 14 This is a schematic diagram of construction steps S7 in the construction method of the bottom formwork connection system of the present invention.

[0031] Figure 15 for Figure 14 Sectional view 1-1.

[0032] Figure 16 and Figure 18 This is a schematic diagram of the construction steps S8 in the construction method of the bottom formwork connection system of the present invention.

[0033] Figure 17 for Figure 16 Sectional view 1-1.

[0034] Figure 19 for Figure 18 Sectional view 1-1.

[0035] Figure 20 and Figure 22 This is a schematic diagram of the construction steps S9 in the construction method of the bottom formwork connection system of the present invention.

[0036] Figure 21 for Figure 20 Sectional view 1-1.

[0037] Figure 23 for Figure 21 Sectional view 1-1.

[0038] Figure 24 This is a schematic diagram of the bottom mold connection system in this invention. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0040] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious modifications will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0041] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0042] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0043] like Figure 1-23 As shown, the present invention provides the following technical solution: a bottom formwork connection system for concrete beam construction adapted to water level fluctuation environment, including bottom formwork main beam 1, at least two sets of L-shaped bolts 2, straight connecting steel bars 3, at least two anchoring steel pipes 4, and fixing steel bars 5; Two bottom formwork main beams 1 are symmetrically arranged on both sides of the pile foundation 6, and bolt holes are opened on the upper and lower flanges of each bottom formwork main beam 1; Both ends of the L-shaped screw 2 are provided with external threads. The horizontal section of the L-shaped screw 2 rests on the top surface of the pier or bored pile, and the vertical section of the L-shaped screw 2 passes through the bolt holes of the bottom formwork main beam 1. One end of the straight connecting steel bar 3 is detachably connected to the horizontal end of the first group of L-shaped screws 2 and the horizontal end of the second group of L-shaped screws 2, respectively. The anchoring steel pipe 4 is embedded in the concrete at the top of the pile foundation 6, and the anchoring steel pipe 4 is sleeved on the anchoring steel bar of the pile foundation 6 and fixedly connected to the anchoring steel bar. The fixing steel bar 5 is respectively tied to the straight connecting steel bar 3 and the anchoring steel pipe 4.

[0044] In the above technical solution, under fluctuating water levels, the exposed anchoring steel bars at the top of the pile foundation 6 and the pre-embedded anchoring steel pipe 4 form a fixed support point. The horizontal section of the L-shaped long screw 2 relies on the top surface of the pile foundation 6 for support, and the vertical section passes through the bolt holes of the bottom formwork main beam 1 to achieve the suspension support of the bottom formwork main beam 1. The bottom formwork main beam 1 bears all the loads of the upper supporting beams, formwork and concrete. The load is transferred to the L-shaped long screw 2 through the bottom formwork main beam 1, and then transferred to the top surface of the pile foundation 6 and the anchoring steel pipe 4 structure by the L-shaped long screw 2. The straight connecting steel bars 3 connect the two sets of L-shaped long screw 2 into an integral frame to offset the lateral force generated by water flow impact and construction disturbance, and to prevent the L-shaped long screw 2 from deviating. The fixing steel bars 5 further bind the integral frame to the anchoring steel pipe 4, and strengthen the overall rigidity of the system. The system eliminates the need for clamps or welded brackets on the piers during installation. Even when the water level exceeds the top surface of pile foundation 6, construction workers can complete component connections underwater, resolving the issue of downtime caused by rising water levels. The system, through modular component assembly and clamp-free support design, enables continuous construction in environments with fluctuating water levels. The core utilizes L-shaped bolts 2 as support points for the main beam 1 of the bottom formwork, completely eliminating the complex procedures of installing steel clamps and welding steel brackets in traditional processes. Even when the water level is higher than the top of the piers or pile foundation 6, construction workers can still complete bolt tightening operations underwater, effectively avoiding downtime during beam bottom formwork installation at high water levels. In areas with semi-diurnal tides, it ensures all-day operation, improving installation efficiency by approximately 50%. All system components can be fabricated using short steel bar ends and steel pipe ends from engineering waste, achieving waste recycling and saving approximately 15% in costs compared to the steel clamp solution. Compared to the steel cofferdam solution, the cost of the formwork system formed by this bottom formwork connection system is only 10% to 30% of its cost. The symmetrical arrangement of the bottom formwork main beam 1 ensures balanced stress, the cooperation of L-shaped screws 2 and anchoring steel pipes 4 improves the safety of underwater construction, and the dual constraint of direct connecting steel bars 3 and fixed steel bars 5 enhances the system's resistance to water flow disturbance and avoids the deviation and deformation of the support system during construction. The overall system combines economy, convenience and stability, and is suitable for the construction needs of concrete beams under various water level fluctuation conditions.

[0045] The present invention also provides the following technical solution, which further includes a nut assembly, comprising an upper nut 8 and a lower nut 9. The upper nut 8 is screwed onto the vertical section of the L-shaped screw 2 and located above the upper flange of the bottom mold main beam 1. The lower nut is screwed onto the vertical section of the L-shaped screw 2 and located below the lower flange of the bottom mold main beam 1. The upper nut and the lower nut 9 together clamp and fix the bottom mold main beam 1.

[0046] In the above embodiment, the upper nut is screwed onto the vertical section of the L-shaped long screw 2 and is located above the upper flange of the bottom formwork main beam 1, and the lower nut is screwed onto the vertical section of the L-shaped long screw 2 and is located below the lower flange of the bottom formwork main beam 1. The upper nut and the lower nut clamp the flange of the bottom formwork main beam 1 from the upper and lower directions respectively, forming a rigid clamping and fixing structure to prevent the bottom formwork main beam 1 from moving up and down under the action of construction load.

[0047] In this system, after the vertical section of the L-shaped long screw rod 2 passes through the bolt holes of the main beam 1 of the bottom formwork, the upper nut is first screwed in to the set elevation position, with the upper flange of the main beam 1 adhering to the bottom surface of the upper nut, achieving initial positioning of the elevation of the main beam 1. Then, the lower nut is screwed in from below the main beam 1 until the top surface of the lower nut is tightly adhering to the lower flange of the main beam 1. Through the bidirectional clamping of the upper and lower nuts, the main beam 1 is fixed at the designated position of the L-shaped long screw rod 2. The load is transferred from the main beam 1 to the lower nut, then through the threaded engagement to the L-shaped long screw rod 2, and finally to the support structure of the pile foundation 6. During elevation adjustment, the position of the upper nut in the vertical section can be changed by rotating it, causing the main beam 1 to move up and down, achieving precise fine-tuning of the elevation. The nut assembly, through its bidirectional clamping design, enables flexible adjustment and fixation of the elevation of the main beam 1, adapting to the construction requirements of different crossbeam bottom elevations. The combination of multiple nuts can meet the needs of high-load construction scenarios and improve the system's load-bearing safety. The threaded connection between the nut and the L-shaped screw 2 is simple to operate, and the tightening operation can be completed even in underwater environments without special tools, reducing construction difficulty. The clamping and fixing structure prevents vertical displacement of the bottom formwork main beam 1, ensuring the stability of the formwork system during concrete pouring, improving the forming accuracy of the crossbeam, and at the same time, the nut assembly is easy to assemble and disassemble, facilitating the dismantling of the bottom formwork system and the reuse of components, further reducing construction costs.

[0048] The present invention also provides the following technical solution: both ends of the straight connecting steel bar 3 are provided with external threads, and both ends of the straight connecting steel bar 3 are respectively threaded to one end of the steel bar connector, and the other end of the steel bar connector is threaded to the horizontal end of the L-shaped screw 2.

[0049] In the above embodiment, the straight connecting steel bar 3 is connected to the horizontal sections of two sets of L-shaped long screw rods 2 through steel bar connectors at both ends, forming a transverse connection frame. This integrates the two independent sets of L-shaped long screw rods 2 into one unit, allowing them to jointly withstand water flow impact and construction loads, thus preventing uneven load distribution on individual L-shaped long screw rods 2. The steel bar connectors transmit axial tensile force and transverse shear force through the interlocking of internal and external threads, ensuring the integrity of the connection node. During underwater construction, docking and disassembly can be completed by rotating the steel bar connectors, eliminating the need for welding. Furthermore, the threaded connection structure adopts a fully detachable design, eliminating the need for on-site welding, adapting to the underwater construction requirements under fluctuating water levels, and ensuring the connection strength meets the construction load-bearing requirements, avoiding the problem of welding operations being impossible underwater. The steel bar connectors are highly versatile and can be matched with steel bar components of different specifications, improving system adaptability, with high docking and disassembly efficiency, shortening the installation cycle of the support system. At the same time, the connection node has sufficient rigidity, effectively resisting water flow disturbance, ensuring that the support system does not loosen or shift during concrete pouring, improving construction safety and beam forming quality.

[0050] Another technical solution of the present invention provides a construction method based on the bottom formwork connection system, comprising the following steps: S1, such as Figure 1 As shown, when binding the reinforcing cage of pile foundation 6, the anchoring steel pipe 4 is sleeved on the anchoring steel bar 7 at the top of the reinforcing cage of pile foundation 6 and fixed. The reinforcing cage is lowered and concrete is poured into the reinforcing cage so that the lower part of the anchoring steel pipe 4 is embedded in the concrete. Bolt holes that penetrate the upper and lower flanges are opened on the upper and lower flanges of the bottom formwork main beam 1, respectively. L-shaped screws 2 with external threads at both ends and straight connecting steel bars 3 with external threads at both ends are processed. S2, such as Figure 2 As shown, the bottom formwork main beam 1 is hoisted to the top surface of the pile foundation 6. The vertical section of the first set of L-shaped screw rods 2 is sequentially inserted into the upper nut 8, the bolt hole of the bottom formwork main beam 1 and the lower nut 9. The elevation of the bottom formwork main beam 1 is controlled by adjusting the position of the upper nut 8 in the vertical section of the L-shaped screw rod 2. S3, such as Figure 3 As shown, one end of the hand chain hoist 10 is wrapped around the bottom formwork main beam 1, and the other end of the hand chain hoist is hooked onto the anchor steel pipe 4 to tighten the hand chain hoist 10. S4, such as Figure 4 As shown, continue to lower the bottom formwork main beam 1 to the elevation of the bottom formwork support part, and at the same time tighten the hand chain hoist. By finely adjusting the plane position of the main beam through the chain hoist, the L-shaped screw 2 is basically located in the center of the pile foundation 6. At this time, the first set of L-shaped screws 2 temporarily fixes the bottom formwork main beam 1. S5, such as Figure 5 As shown, repeat S2-S4 until the temporary fixing of the second set of L-shaped screws 2 to the other side of the bottom formwork main beam 1 is completed; S6, such as Figure 6 and Figure 7 As shown, one end of the straight connecting steel bar 3 is connected to the horizontal end of the first group of L-shaped screw rods 2 through the steel bar connector 11, and the other end of the straight connecting steel bar 3 is connected to the horizontal end of the second group of L-shaped screw rods 2 through the steel bar connector 11. S7, such as Figure 8 As shown, the straight connecting steel bar 3 and the anchoring steel pipe 4 are tied together by the fixing steel bar 5, and the hand chain hoist is removed. S8, such as Figure 9 As shown, the bottom formwork secondary beam and bottom formwork are installed on the bottom formwork main beam 1, forming an integral formwork 12, as shown. Figure 10 As shown, after installing the side formwork 13, the crossbeam concrete 14 is poured. S9, such as Figure 11 As shown, after the concrete of the crossbeam reaches the design strength, remove the side formwork, and screw down the lower nut to lower the main beam 1 of the bottom formwork. Then, remove the bottom formwork and the secondary beam of the bottom formwork. Figure 12 As shown, cut off the part of the L-shaped screw 2 that extends out of the bottom of the crossbeam and lift it away from the bottom formwork main beam 1.

[0051] In the above implementation scheme, in S1, during the stage of binding the reinforcement cage of pile foundation 6, the anchoring steel pipe 4 is inserted into the top anchoring steel bar, the pre-embedded depth is adjusted and then spot-welded for fixation, the reinforcement cage is lowered and concrete is poured, and at the same time, the bolt holes of the bottom formwork main beam 1 and the threading of the L-shaped long screw 2 and the straight connecting steel bar 3 are completed in the processing plant; in S2, the bottom formwork main beam 1 is hoisted to the top surface of pile foundation 6 using a floating crane or crawler crane, and the vertical section of the L-shaped long screw 2 is sequentially inserted into the upper nut, the bolt hole of the bottom formwork main beam 1 and the lower nut, and the upper nut is rotated to the design elevation position to complete the preliminary control of the elevation of the bottom formwork main beam 1; in S3, one end of the chain of the hand-operated hoist is wrapped around the bottom formwork main beam 1, and the other end is hooked on the anchoring steel pipe 4, and the hand-operated hoist is manually tightened to put the bottom formwork main beam 1 in a tensioned state; in S4 In step S2, the main beam 1 of the bottom formwork is slowly lowered to the support elevation, and the hand-operated hoist is continuously tightened to fine-tune the plane position so that the L-shaped screw 2 is located in the center of the pile foundation 6, completing the temporary fixation on one side; in step S5, the operation from S2 to S5 is repeated to complete the temporary fixation of the main beam 1 of the bottom formwork on the other side, ensuring symmetrical force on both sides; in step S6, the two ends of the straight connecting steel bar 3 are connected to the horizontal sections of the two sets of L-shaped long screw 2 respectively through the steel bar connector, and the connector is tightened to ensure a firm connection; in step S7, the straight connecting steel bar 3 is tied to the anchor steel pipe 4 with the fixing steel bar 5 to form an overall stable system, and then the hand-operated hoist is removed; in step S8, the secondary beam of the bottom formwork and the bottom formwork are laid on the main beam 1 of the bottom formwork, and the side formwork is installed before pouring concrete; in step S9, after the concrete reaches the design strength, the side formwork is removed, the lower nut is turned downward to lower the main beam 1 of the bottom formwork, the formwork and the secondary beam are pulled out, the exposed L-shaped screw 2 is cut off, and the main beam 1 of the bottom formwork is lifted away to complete the construction. The entire construction process eliminates the need for clamps, corbels, and cofferdams, completely solving the problem of construction being impossible when the water level exceeds the top surface of the piers or piles in traditional methods. All installation work can be completed in high-water environments, effectively avoiding downtime. In areas with semi-diurnal tides, work can be carried out all day, increasing overall installation efficiency by approximately 50% compared to traditional methods. During construction, scrap materials are fully utilized, saving approximately 15% in costs compared to steel clamp solutions, and only 10% to 30% of the cost of the formwork system compared to steel cofferdam solutions. During dismantling, no additional auxiliary components are required; simply tightening the lower nuts lowers the main beam, allowing the formwork and secondary beams to be directly removed. After cutting off the exposed bolts, the main beam can be lifted away, reducing dismantling costs by approximately 20% and increasing dismantling efficiency by approximately 50%. This method is suitable for various water level fluctuations in rivers, harbors, and seaports, offering high construction safety, stable concrete beam forming quality, and combining economic efficiency with practicality.

[0052] The present invention also provides the following technical solution: after the main beam is temporarily fixed in step S4, the hand-operated hoist is kept in a state of slight tension, and then the straight connection steel bar 3 is connected to the steel bar connector and tightened in step S6, so that the tension constraint force and the thread tightening force constrain each other and prevent the connection node from loosening and shifting under the disturbance of water flow.

[0053] In the above implementation scheme, the micro-tensioned stress state refers to the state in which the hand-operated hoist maintains a slight tension force, neither loosening nor over-tensioning, which can counteract the influence of water flow disturbance. The tension constraint force is the pulling force applied by the hand-operated hoist to the bottom formwork main beam 1, and the thread tightening force is the axial force generated when the rebar connector is tightened. The connection node refers to the docking position of the straight connecting rebar 3, the rebar connector, and the L-shaped long screw 2. Specifically, after the temporary fixing of the bottom formwork main beam 1 is completed in step S4, the hand-operated hoist is not loosened and is maintained in a micro-tensioned stress state to keep the positions of the bottom formwork main beam 1 and the L-shaped long screw 2 fixed. Under this premise, the docking of the straight connecting rebar 3 and the tightening of the rebar connector in step S6 are performed. When tightening the rebar connector, the axial thrust generated by the thread tightening will cause the straight connecting rebar 3 and the L-shaped long screw 2 to tend to misalign. However, the tensioning constraint force of the hand-operated hoist will counteract this thrust and resist the impact force of the water flow in the construction area, preventing the joint from loosening, shifting, or misaligning under the disturbance of water flow and tightening force. The micro-tension state can be controlled with the assistance of a force gauge or determined by the construction personnel by touch.

[0054] This application ensures the connection accuracy between the straight-connected rebar 3 and the L-shaped long screw 2 through the coordinated operation of micro-tension constraint and threaded tightening, avoiding node deviations caused by water flow disturbance and tightening force, and improving the integrity and stability of the connection node. No additional positioning fixtures are required; constraint can be achieved using existing hand-operated hoists, making operation simple and without increasing construction procedures or costs. This ensures that the support system does not deform during the rebar connection stage, providing a stable support foundation for subsequent concrete pouring.

[0055] The present invention also provides the following technical solution: In step S4, when the hand chain hoist is kept in a state of slight tension, the tension constraint force is made greater than the impact force of the water flow in the construction area. The tension constraint force is kept constant throughout the tightening process of the rebar connector, so as to use the tension constraint force to offset the axial thrust generated by the thread tightening, and ensure that the straight connection rebar 3 and the L-shaped long screw 2 are coaxially connected. After the rebar connector is tightened, continue to keep the hand-operated hoist in a slightly tensioned state and let it stand still, so that the tension constraint force and the thread locking force are coupled to form a stable force system; After the initial settling period, gradually reduce the tension of the chain hoist in stages until it is under slight tension and no further loosening is required.

[0056] In the above technical solution, step S4 maintains a slight tension on the hand-operated hoist, ensuring that the tension constraint force is greater than the impact force of the water flow in the construction area. This prevents the water flow from displacing the bottom formwork main beam 1 and the L-shaped long screw 2. Throughout the tightening process of the rebar connector, this tension constraint force remains constant. This constant tension constraint force counteracts the axial thrust generated by the thread tightening, ensuring that the direct-connecting rebar 3 and the L-shaped long screw 2 remain coaxially aligned. After the rebar connector is tightened, the hand-operated hoist is kept in a slightly tensioned state and left to stand, allowing the tension constraint force and the thread locking force to fully integrate and form a stable internal force system. After standing, the tension force of the hand-operated hoist is gradually reduced in stages until the hand-operated hoist is in a slightly tensioned state. At this point, the loosening operation is stopped, while the limiting constraint function is retained. The above method precisely controls the stress state during the rebar splicing stage through constant tension and load maintenance, static force coupling, and graded stress reduction operations. This solves the splicing deviation problems caused by water flow disturbance and tightening jacking, improving the construction accuracy of the connection nodes. Coaxial splicing ensures uniform stress on the components, avoiding excessive local stress that could damage them. The slight tension retains a limiting effect, further enhancing the stability of the support system.

[0057] The present invention also provides the following technical solution: when the hand chain hoist is kept under slight tension and stationary, the tension force value of the hand chain hoist is first recorded. During the stationary period, the force value is monitored in real time. If the value fluctuates, the hand chain hoist is finely adjusted in time to maintain a constant force. After the stationary period is completed, the tension force is reduced slightly and the connection state between the straight connecting steel bar 3 and the L-shaped screw 2 is observed. After confirming that there is no displacement, the tension force of the hand chain hoist is gradually reduced in stages until the hand chain hoist is in a slightly tensioned state.

[0058] In the above technical solution, when the hand-operated chain hoist is kept under slight tension and stationary, the current tension force value of the hand-operated chain hoist is first recorded as a benchmark control value. During the stationary period, this force value is continuously monitored in real time. If the value fluctuates upward or downward, the tension force of the hand-operated chain hoist is immediately fine-tuned to keep the force near the benchmark value and ensure stable force. After the stationary period, the tension force of the hand-operated chain hoist is slightly reduced, the operation is stopped, and the connection status of the straight connecting steel bar 3 and the L-shaped long screw 2 is observed. After confirming that there is no displacement, loosening, or misalignment, the tension force of the hand-operated chain hoist is gradually reduced in stages. The observation and confirmation steps are repeated for each adjustment until the hand-operated chain hoist reaches a slightly tensioned state. The method ensures constant force during the stationary stage through real-time monitoring and dynamic fine-tuning, avoids deformation of the support system caused by external force fluctuations, and combines staged force reduction with state confirmation to achieve a smooth transition of the force state and prevent loosening of nodes caused by a one-time force reduction. The meticulous operation throughout the process enhances the controllability and precision of construction, ensuring that the connection nodes remain stable at all times. It adapts to complex construction environments with fluctuating water levels and rapid water flow, further strengthening the reliability of the support system and providing a guarantee for high-quality construction of concrete beams.

[0059] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A bottom formwork connection system for concrete beam construction adapted to water level fluctuation environments, characterized in that, Includes bottom formwork main beam, at least two sets of L-shaped bolts, straight connecting steel bars, at least two anchoring steel pipes, and fixing steel bars; The two bottom formwork main beams are symmetrically arranged on both sides of the pile foundation, and bolt holes are opened on the upper and lower flanges of each bottom formwork main beam; Both ends of the L-shaped screw are provided with external threads. The horizontal section of the L-shaped screw rests on the top surface of the pier or bored pile, and the vertical section of the L-shaped screw passes through the bolt holes of the bottom formwork main beam. One end of the straight connecting steel bar is detachably connected to the horizontal end of the first group of L-shaped screws and the horizontal end of the second group of L-shaped screws, respectively; The anchoring steel pipe is embedded in the concrete at the top of the pile foundation, and the anchoring steel pipe is sleeved on the anchoring steel bar of the pile foundation and fixedly connected to the anchoring steel bar. The fixing reinforcing bars are respectively tied to the direct connecting reinforcing bars and the anchoring steel pipe.

2. The bottom formwork connection system for concrete beam construction under fluctuating water levels as described in claim 1, characterized in that, It also includes a nut assembly, which includes an upper nut and a lower nut. The upper nut is screwed onto the vertical section of the L-shaped screw and is located above the upper flange of the bottom mold main beam. The lower nut is screwed onto the vertical section of the L-shaped screw and is located below the lower flange of the bottom mold main beam. The upper nut and the lower nut together clamp and fix the bottom mold main beam.

3. The bottom formwork connection system for concrete beam construction adapted to water level fluctuation environments according to claim 1, characterized in that, Both ends of the straight connecting steel bar are provided with external threads. Both ends of the straight connecting steel bar are respectively threaded to one end of the steel bar connector, and the other end of the steel bar connector is threaded to the horizontal end of the L-shaped screw.

4. A construction method based on the bottom formwork connection system according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. When binding the pile foundation reinforcement cage, the anchoring steel pipe is sleeved on the anchoring steel bar at the top of the pile foundation reinforcement cage and fixed. The reinforcement cage is lowered and concrete is poured into the reinforcement cage so that the lower part of the anchoring steel pipe is embedded in the concrete. Bolt holes that penetrate the upper and lower flanges are opened on the upper and lower flanges of the bottom formwork main beam, respectively. L-shaped threaded rods with external threads at both ends and straight connecting steel bars with external threads at both ends are processed. S2. Hoist the bottom formwork main beam to the top surface of the pile foundation. Insert the vertical section of the first set of L-shaped screws into the upper nut, the bolt hole of the bottom formwork main beam and the lower nut in sequence. Control the elevation of the bottom formwork main beam by adjusting the position of the upper nut on the vertical section of the L-shaped screw. S3. Use a hand-operated hoist to wrap one end around the bottom formwork main beam, and hook the other end of the hand-operated hoist onto the anchoring steel pipe, then tighten the hand-operated hoist. S4. Continue to lower the bottom formwork main beam to the elevation of the bottom formwork support part, and at the same time tighten the hand chain hoist. Use the chain hoist to fine adjust the plane position of the main beam so that the L-shaped screw is basically located in the center of the pile foundation. At this time, the first set of L-shaped screws temporarily fixes the bottom formwork main beam. S5. Repeat S2-S4 until the second set of L-shaped screws is used to temporarily fix the other side of the bottom formwork main beam. S6. Connect one end of the straight connecting steel bar to the end of the horizontal section of the first group of L-shaped screw rods through the steel bar connector. Figure 7. Connect the other end of the straight connecting steel bar to the end of the horizontal section of the second group of L-shaped screw rods through the steel bar connector. S7. Use fixed steel bars to tie the straight connecting steel bars to the anchoring steel pipe and remove the hand chain hoist; S8. Install the bottom formwork secondary beam and bottom formwork on the bottom formwork main beam. After installing the side formwork, pour the cross beam concrete. (Figure 10) S9. After the concrete of the crossbeam reaches the design strength, remove the side formwork, turn the lower nut downward to lower the main beam of the bottom formwork, pull out the bottom formwork and the secondary beam of the bottom formwork, cut off the part of the L-shaped screw that extends out of the bottom of the crossbeam, and lift it away from the main beam of the bottom formwork.

5. The construction method according to claim 4, characterized in that, After the main beam is temporarily fixed in step S4, keep the hand-operated hoist under slight tension and then perform the straight connection steel bar butt joint and steel bar connector tightening operation in step S6. This will make the tension constraint force and the thread tightening force mutually constrain each other and prevent the connection node from loosening and shifting under the disturbance of water flow.

6. The construction method according to claim 5, characterized in that, In step S4, when the hand chain hoist is kept in a slightly tensioned state, the tension constraint force is made greater than the impact force of the water flow in the construction area. The tension constraint force is kept constant throughout the tightening process of the rebar connector, so as to use the tension constraint force to counteract the axial thrust generated by the thread tightening, and ensure that the straight connection rebar and the L-shaped screw are coaxially connected. After the rebar connector is tightened, continue to keep the hand-operated hoist in a slightly tensioned state and let it stand still, so that the tension constraint force and the thread locking force are coupled to form a stable force system; After the initial settling period, gradually reduce the tension of the chain hoist in stages until it is under slight tension and no further loosening is required.

7. The construction method according to claim 6, characterized in that, When maintaining the hand chain hoist under slight tension and allowing it to stand still, first record the tension force value of the hand chain hoist at this time. During the resting process, monitor this force value in real time. If the value fluctuates, adjust the hand chain hoist in time to maintain a constant force. After the resting is complete, first reduce the tension force slightly and observe the connection status between the straight connecting steel bar and the L-shaped bolt. After confirming that there is no displacement, continue to gradually reduce the tension force of the hand chain hoist until the hand chain hoist is in a slightly tensioned state.

Images