Slip-form cantilever cast-in-place structure operation platform construction method

Abstract

The application discloses a sliding form overhanging cast-in-place structure operation platform construction method and belongs to the technical field of building sliding form construction. Two types of sleeves are synchronously pre-buried in the cylinder wall sliding form pouring stage. One type of high-strength bolt sleeve is used for assembling a later-stage overhanging load-bearing hanging frame, thereby forming an independent high-altitude formwork operation platform. Another type of straight thread sleeve assembly realizes mechanical connection of overhanging reinforcement and does not need to bend and pre-bury reinforcement. The construction process sequentially completes sleeve pre-burial, cylinder wall sliding lifting pouring, hanging frame assembly and support formwork erection, removal of sliding form equipment, reinforcement straight thread lengthening binding, multi-process acceptance and pouring and curing of concrete, and the formwork and the hanging frame are sequentially removed and exposed sleeve points are repaired after reaching the standard. The super-high floor-mounted scaffold and special demonstration are cancelled, hidden troubles of the structure, such as reinforcement fatigue fracture and local over-reinforcement of a thin wall, are eliminated, material, labor and construction period costs are greatly reduced, the cylinder wall forming appearance is better, and the method is suitable for overhanging cast-in-place component construction of various vertical thin-wall sliding form structures, such as silos, chimneys and the like.

Description

Technical Field

[0001] This invention relates to the field of slipform construction technology, specifically a slipform operation platform construction method for cast-in-place structures. Background Technology

[0002] Slip-form construction of vertical thin-walled structures offers advantages such as continuous formwork sliding, high mechanization, and excellent structural integrity, and is widely used in the construction of various cylindrical thin-walled civil structures. However, the cantilevered cast-in-place components of the structure's outer wall cannot be slip-formed and cast simultaneously with the main body of the silo structure, presenting two major challenges for subsequent separate construction:

[0003] First, there are defects in the pre-embedding and anchoring of reinforcing bars in cantilevered components. Traditional construction methods pre-embed reinforcing bars for cantilevered structures. During slipforming, these bars must be bent inwards and tucked into the structural cover. After slipforming is complete, the concrete is chipped away, and the bars are bent back to their designed positions. Repeated bending of Grade III reinforcing bars can easily lead to metal fatigue fracture. In thin-walled silo structures with limited internal space, concentrated arrangement of bent and anchored reinforcing bars can cause localized over-reinforcement of the concrete, resulting in insufficient concrete bond strength and posing a permanent structural safety hazard. Using post-installed rebar alone also presents problems such as insufficient bond strength, poor durability, and high risks associated with high-altitude rebar installation.

[0004] Secondly, the construction of the formwork support platform for cantilevered components presents significant costs and safety risks. The formwork support system for high-altitude cantilevered cast-in-place components requires a complete working surface. Traditional solutions employ ground-mounted ultra-high scaffolding, which is considered a high-risk sub-project exceeding a certain scale and requires specialized expert review. The construction of ultra-high ground-mounted scaffolding involves a massive amount of material and labor costs, and the erection and dismantling process is lengthy, requiring the scaffolding to be dismantled only after the concrete of the cantilevered components has fully reached its design strength, severely slowing down the overall construction progress.

[0005] To address this, a construction method for a slipform cantilevered cast-in-place structure operating platform is proposed, which eliminates the need for ultra-high ground-based scaffolding and repeated bending of reinforcing bars. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a construction method for a slipform cantilever cast-in-place structure operating platform that eliminates the need for ultra-high ground-based scaffolding and repeated bending of reinforcing bars.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A construction method for a slipform cantilever cast-in-place structure operating platform includes the following steps:

[0009] Step 1: During the main construction of the outer wall of the silo structure, high-strength bolt sleeves are pre-embedded simultaneously. The tail of the sleeve is welded and fixed to the internal steel bars of the outer wall of the silo structure, and the inside of the sleeve is filled with flexible sealing material.

[0010] Step 2: Pre-embed straight threaded sleeve assembly at the elevation position of the outer wall of the silo structure corresponding to the cantilever component. The sleeve assembly consists of multiple sets of straight threaded sleeves and transversely welded anchoring steel bars. The inside of the sleeve is filled with flexible fabric for sealing.

[0011] Step 3: After completing the pre-embedding of the two sets of sleeves, start the slipform equipment to continuously slide upwards and pour the concrete of the outer wall of the silo structure in sections until the main structure of the outer wall of the silo structure is formed.

[0012] Step 4: Complete the assembly of the external load-bearing bracket, clean the surface concrete of the outer wall of the silo structure and remove the sealing material inside the high-strength bolt sleeve, use high-strength bolts to fasten the bracket to the pre-embedded high-strength bolt sleeve, fully cover the surface of the bracket with steel walkway plates, install safety nets at the bottom of the bracket, and build a support frame for the cantilevered components with the bracket as the load-bearing base.

[0013] Step 5: Completely dismantle the slipform lifting and formwork equipment, mark the position of the straight threaded sleeve, partially remove the surface concrete and blow away the dust inside the straight threaded sleeve;

[0014] Step 6: Screw the cantilevered reinforcing bars with pre-drilled threads into the straight thread sleeve. Use a torque wrench to check the connection torque of the cantilevered reinforcing bars. Once the torque meets the standard, tie the distributed reinforcing bars of the cantilevered components to form a complete reinforcing mesh.

[0015] Step 7: After passing multiple inspections, pour concrete for the cantilevered components and cure them according to the specifications until the concrete reaches the design strength.

[0016] Step 8: Remove the cantilevered component support formwork and external load-bearing brackets from top to bottom, clean the exposed high-strength bolt sleeves on the outer wall of the silo structure and perform plastering and sealing repair.

[0017] Furthermore, in the first step, two high-strength bolt sleeves are set in each group. The two sleeves together form a set of force-bearing units. During the construction force verification process, the bearing capacity is calculated according to the bearing standard of a single sleeve. The other sleeve serves as a safety backup force-bearing component. All sleeves are evenly arranged circumferentially along the outer wall of the silo structure.

[0018] Furthermore, in the second step, the straight threaded sleeve assembly is arranged in two rows of sleeves, with the anchoring steel bars at the tail of the sleeves being horizontally welded together to form an integral skeleton structure. The ends of the anchoring steel bars extend half their length into the sleeve, and a gap is reserved between the ends of the sleeves and the outer template of the slipform.

[0019] Furthermore, in the fourth step, the circumferential spacing of the external load-bearing brackets is consistent with the circumferential spacing of the pre-embedded high-strength bolt sleeves, and the support frame uprights are locked and fixed to the upper part of the brackets through scaffolding pipes and cross buckles.

[0020] Furthermore, in the sixth step, after the cantilevered reinforcing bars are connected to the straight threaded sleeve, the concealed process of the reinforcing bars is inspected. The inspection includes three core indicators: sleeve connection torque, reinforcing bar spacing, and reinforcing bar protective layer thickness.

[0021] Furthermore, in the seventh step, the multi-process acceptance includes the acceptance of the formwork support system, the acceptance of the concealed reinforcement, and the acceptance of the component dimensions. Concrete pouring can only be carried out after all three acceptances are qualified.

[0022] Furthermore, the eighth step of the demolition work follows the vertical demolition sequence of first dismantling the upper support formwork and then dismantling the external load-bearing bracket. After the demolition is completed, the exposed sleeve positions on the outer wall of the silo structure are repaired with surface plaster to eliminate pit defects on the outer wall surface of the silo structure.

[0023] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0024] 1. Eliminate permanent structural safety hazards: The use of pre-embedded straight threaded sleeves for mechanical connection replaces the repeated bending of steel bars. Grade III steel bars are free from bending fatigue damage. The sleeves are distributed to avoid local over-reinforcement on the outer wall of the thin-walled silo structure. The steel bar anchorage force is uniform, the concrete bonding effect is stable, and the durability and load-bearing safety of the cantilevered components are greatly improved.

[0025] 2. Avoid dangerous and large-scale projects and significantly reduce overall construction costs: Eliminate the process of erecting ultra-high ground scaffolding, eliminate the need for expert demonstration on scaffolding, significantly reduce the input of turnover materials such as steel pipes, fasteners, and scaffold boards, and save labor and construction period costs for the erection and dismantling of ultra-high scaffolding.

[0026] 3. Significantly shortened construction period: The hanging frame is pre-embedded simultaneously with the slipform construction and quickly assembled later, eliminating the need to wait for the erection of the ground scaffolding; the formwork and hanging frame can be removed simultaneously after the concrete curing meets the standards, eliminating the need for excessively long scaffolding retention time, and shortening the overall construction period by more than half.

[0027] 4. High-altitude operation is safe and controllable: The external hanging frame is anchored to the outer wall of the silo structure with pre-embedded high-strength bolt sleeves. The double sleeves, one for use and one for backup, are set to improve the overall pull-out safety reserve. The bottom of the hanging frame is fully covered with safety netting, and the working surface is fully covered with steel walkway plates, eliminating the risk of high-altitude suspended operation near the edge.

[0028] 5. Excellent structural appearance: The sleeve is filled with flexible sealing material during the pre-embedding stage, and there is no grout clogging the sleeve during pouring; after the bracket is removed, only local plastering is needed to seal the sleeve points, without the need for large-area concrete chiseling and repair, and the color difference and damage defects of the outer wall surface of the silo structure are greatly reduced. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the plan view of the silo wall and the cantilever structure to be poured in an embodiment of the present invention;

[0030] Figure 2 This is a cross-sectional view and structural schematic diagram of the silo wall and the cantilever structure to be poured in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the distribution structure of the steel reinforcement connectors at the cantilevered part of the warehouse wall in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the distribution structure of the cantilevered steel mesh in an embodiment of the present invention;

[0033] Figure 5 This is a cross-sectional structural diagram of the external load-bearing bracket installation in an embodiment of the present invention;

[0034] Figure 6 This is a cross-sectional structural diagram of the cantilever component support frame installation in an embodiment of the present invention.

[0035] Explanation of reference numerals in the attached drawings: 1. Outer wall of silo structure; 2. Transverse welded anchoring steel bar; 3. Anchoring steel bar; 4. Straight threaded sleeve; 5. Outer stressed steel bar; 6. Outer distributed steel bar of the outer component; 7. High-strength bolt sleeve; 8. High-strength bolt; 9. External load-bearing bracket; 10. Outer component support formwork; 11. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to specific embodiments. The purpose of this illustration is solely to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0037] like Figures 1 to 6 As shown in the figure, this embodiment provides a construction method for an operating platform for a slipform cantilever cast-in-place structure, including the following steps:

[0038] Step 1: During the main construction stage of the outer wall 1 of the silo structure, high-strength bolt sleeves 8 are pre-embedded simultaneously. The tail of the sleeve is welded and fixed to the internal steel reinforcement of the outer wall 1 of the silo structure. The inside of the sleeve is filled with flexible sealing material. Two high-strength bolt sleeves 8 are set in each group. The two sleeves together form a set of load-bearing units. During the construction load verification process, the load-bearing capacity is calculated according to the load-bearing standard of a single sleeve. The other sleeve is used as a safety backup load-bearing component. All sleeves are evenly arranged around the outer wall 1 of the silo structure.

[0039] Step 2: Embed a straight threaded sleeve 5 assembly at the elevation position of the outer wall 1 of the silo structure corresponding to the cantilever component 2. The sleeve assembly consists of multiple sets of straight threaded sleeves 5 and transversely welded anchoring steel bars 3. The inside of the sleeve is filled with flexible fabric for sealing. The straight threaded sleeve 5 assembly is arranged in two rows of sleeves, and the anchoring steel bars 4 at the tail of the straight threaded sleeves 5 are transversely welded to form an integral skeleton structure. The end of the anchoring steel bar 4 extends into the inside of the sleeve by half its length, and a gap is reserved between the end of the sleeve and the outer template of the slipform.

[0040] Step 3: After completing the pre-embedding of the two sets of sleeves, start the slipform equipment to continuously slide upwards and pour concrete for the outer wall 1 of the silo structure in sections until the main structure of the outer wall 1 of the silo structure is formed;

[0041] Step 4: Complete the assembly of the external load-bearing bracket 10, clean the surface concrete of the outer wall 1 of the silo structure and remove the sealing material inside the high-strength bolt sleeve 8, use high-strength bolts 9 to fasten the bracket to the pre-embedded high-strength bolt sleeve 8, fully cover the surface of the bracket with steel walkway plates, install safety nets at the bottom of the bracket, and erect the cantilever support formwork 11 with the bracket as the load-bearing base; the circumferential spacing of the external load-bearing bracket 10 is consistent with the circumferential spacing of the pre-embedded high-strength bolt sleeve 8, and the support formwork uprights are locked and fixed to the upper part of the bracket with scaffolding pipes and cross buckles.

[0042] Step 5: Completely dismantle the slipform lifting and formwork equipment, mark the position of the straight threaded sleeve 5, partially remove the surface concrete and blow away the dust inside the straight threaded sleeve 5;

[0043] Step 6: Screw the cantilevered reinforcing bars 6 with pre-drilled threads into the straight threaded sleeve 5. Check the connection torque of the cantilevered reinforcing bars 6 with a torque wrench. After the torque meets the standard, tie the distribution reinforcing bars 7 of the cantilevered components to form a complete reinforcing mesh. After the cantilevered reinforcing bars 6 are connected to the straight threaded sleeve 5, carry out the acceptance of the concealed reinforcing bar process. The acceptance includes three core indicators: sleeve connection torque, reinforcing bar spacing, and reinforcing bar protective layer thickness.

[0044] Step 7: After passing multiple inspections, pour concrete for the cantilevered component 2 and cure it according to the specifications until the concrete reaches the design strength. The multiple inspections include the formwork support system inspection, the concealed reinforcement inspection, and the component size verification inspection. Concrete pouring can only be carried out after all three inspections are passed.

[0045] Step 8: Remove the cantilevered component support formwork 11 and the external load-bearing bracket 10 from top to bottom. Clean the exposed high-strength bolt sleeves 8 on the outer wall 1 of the silo structure and perform plaster sealing repair. The demolition work follows the vertical demolition sequence of first removing the upper support formwork and then dismantling the external load-bearing bracket 10. After the demolition is completed, perform surface plaster repair on the exposed sleeve positions on the outer wall 1 of the silo structure to eliminate surface pit defects on the outer wall 1 of the silo structure.

[0046] To enhance the strength of the cantilevered component 2 on the outer wall 1 of the silo structure, while pre-embedding the straight threaded sleeve 5 assembly at the elevation position of the cantilevered component 2 corresponding to the outer wall 1 of the silo structure in the second step, the inner steel bars of the outer wall of the silo structure at this part are connected and reinforced; S-shaped steel bars are used to tighten the adjacent steel bars.

[0047] This invention employs pre-embedded straight threaded sleeves 5 for mechanical connection, replacing the repeated bending of reinforcing bars. This eliminates bending fatigue damage to Grade III reinforcing bars. The dispersed arrangement of sleeves prevents localized over-reinforcement on the outer wall 1 of the thin-walled silo structure, ensuring uniform reinforcing bar anchorage and stable concrete bonding, significantly improving the structural durability and load-bearing safety of the cantilevered components 2. It eliminates the need for the construction of ultra-high ground-based scaffolding, eliminating the need for expert review of scaffolding, and significantly reducing the input of reusable materials such as steel pipes, fasteners, and scaffold boards. This also saves on labor and time costs associated with the construction and dismantling of ultra-high scaffolding. The hanging frame is pre-embedded simultaneously with slipform construction and can be quickly assembled later, eliminating the need to wait for the ground-based scaffolding erection period. Once the concrete has cured to the required standard, the formwork and hanging frame can be dismantled simultaneously, eliminating excessive scaffolding retention time and shortening the overall construction period by more than half. The external mounting bracket is anchored to the outer wall of the silo structure 1 with pre-embedded high-strength bolt sleeves 8. The double sleeve configuration, one for use and one as a backup, enhances the overall pull-out safety reserve. The bottom of the bracket is fully covered with safety netting, and the working surface is fully covered with steel walkways, eliminating the risk of suspended work at heights. During the pre-embedding stage, the sleeves are filled with flexible sealing material, preventing grout blockage during pouring. After the bracket is removed, only local plastering is needed to seal the sleeve locations, eliminating the need for large-area concrete chiseling and repair. This significantly reduces surface color differences and defects on the outer wall of the silo structure 1.

[0048] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A construction method for a slipform cantilever cast-in-place structure operating platform, characterized in that, Includes the following steps: Step 1: During the main construction of the outer wall of the silo structure, high-strength bolt sleeves are pre-embedded simultaneously. The tail of the sleeve is welded and fixed to the internal steel bars of the outer wall of the silo structure, and the inside of the sleeve is filled with flexible sealing material. Step 2: Pre-embed straight threaded sleeve assembly at the elevation position of the outer wall of the silo structure corresponding to the cantilever component. The sleeve assembly consists of multiple sets of straight threaded sleeves and transversely welded anchoring steel bars. The inside of the sleeve is filled with flexible fabric for sealing. Step 3: After completing the pre-embedding of the two sets of sleeves, start the slipform equipment to continuously slide upwards and pour the concrete of the outer wall of the silo structure in sections until the main structure of the outer wall of the silo structure is formed. Step 4: Complete the assembly of the external load-bearing bracket, clean the surface concrete of the outer wall of the silo structure and remove the sealing material inside the high-strength bolt sleeve, use high-strength bolts to fasten the bracket to the pre-embedded high-strength bolt sleeve, fully cover the surface of the bracket with steel walkway plates, install safety nets at the bottom of the bracket, and build a support frame for the cantilevered components with the bracket as the load-bearing base. Step 5: Completely dismantle the slipform lifting and formwork equipment, mark the position of the straight threaded sleeve, partially remove the surface concrete and blow away the dust inside the straight threaded sleeve; Step 6: Screw the cantilevered reinforcing bars with pre-drilled threads into the straight thread sleeve. Use a torque wrench to check the connection torque of the cantilevered reinforcing bars. Once the torque meets the standard, tie the distributed reinforcing bars of the cantilevered components to form a complete reinforcing mesh. Step 7: After passing multiple inspections, pour concrete for the cantilevered components and cure them according to the specifications until the concrete reaches the design strength. Step 8: Remove the cantilevered component support formwork and external load-bearing bracket from top to bottom, clean the exposed high-strength bolt sleeves on the outer wall of the silo structure and perform plastering and sealing repair.

2. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: In the first step, two high-strength bolt sleeves are set in each group. The two sleeves together form a set of force-bearing units. During the construction force verification process, the bearing capacity is calculated according to the bearing standard of a single sleeve. The other sleeve serves as a safety backup force-bearing component. All sleeves are evenly arranged circumferentially along the outer wall of the silo structure.

3. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: In the second step, the straight threaded sleeve assembly is arranged in two rows of sleeves, and the anchoring steel bars at the tail of the sleeve are horizontally welded to form an integral skeleton structure. The ends of the anchoring steel bars extend into the sleeve by half their length, and a gap is reserved between the ends of the sleeve and the outer template of the slip mold.

4. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: In the fourth step, the circumferential spacing of the external load-bearing brackets is consistent with the circumferential spacing of the pre-embedded high-strength bolt sleeves, and the support frame uprights are locked and fixed to the upper part of the brackets through scaffolding pipes and cross buckles.

5. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: In the sixth step, after the cantilevered reinforcing bars are connected to the straight threaded sleeves, the concealed reinforcement process is inspected. The inspection includes three core indicators: sleeve connection torque, reinforcement spacing, and reinforcement protective layer thickness.

6. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: In the seventh step, the multi-process acceptance includes the acceptance of the formwork support system, the acceptance of the concealed reinforcement, and the acceptance of the component dimensions. Concrete pouring can only be carried out after all three acceptances are qualified.

7. The construction method for the slipform cantilever cast-in-place structure operating platform according to claim 1, characterized in that: The eighth step of the demolition work follows the vertical demolition sequence of first removing the upper support formwork and then dismantling the external load-bearing bracket. After the demolition is completed, the exposed sleeve positions on the outer wall of the silo structure are repaired with surface plaster to eliminate pit defects on the outer wall surface of the silo structure.

Images