Construction method for one-step lifting and step-by-step descending of double-pier cap beam support system

Abstract

This invention provides a construction method for a double-pier column cap beam support system that involves a one-step lifting and step-by-step lowering process. The method includes steps such as support system assembly, overall lifting, pre-stressing of the supports, removal of side formwork, step-by-step lowering, and dismantling of the support system. This invention avoids the foundation treatment procedures for soft soil foundations and eliminates the need for pre-embedded conditions, thereby reducing construction costs and accelerating the construction progress.

Description

Technical Field

[0001] This invention relates to the field of double-pier column cap beam construction technology, specifically a construction method for a double-pier column cap beam support system that involves one-step lifting and step-by-step lowering. Background Technology

[0002] For the construction of the cap beams of viaducts, the support system is generally erected using ordinary steel pipe support system or disc-lock scaffolding. The foundation usually needs to be treated, using methods such as replacement, compaction or subbase. Especially for soft soil foundations, special treatment is required, which is more expensive and the quality is difficult to guarantee. There are also cases where steel support system is used for construction, but a lot of pre-embedded conditions are required, which increases the difficulty and cost of construction. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention proposes a construction method for a double-pier column cap beam support system that involves one-step lifting and step-by-step lowering.

[0004] The present invention provides a construction method for a double-pier column cap beam support system that involves one-step lifting and step-by-step lowering, comprising the following steps:

[0005] S1. Support System Assembly: A stabilizing hoop is pre-fixed at the bottom of each pier column, and a lower bearing hoop is pre-fixed above the stabilizing hoop; a stabilizing column is installed to connect the stabilizing hoop and the lower bearing hoop; the main load-bearing steel beam is temporarily fixed to the two pier columns via an upper bearing hoop; a main load-bearing triangular brace is installed to connect the load-bearing platform on the lower bearing hoop to the main load-bearing steel beam, forming a stable system; a stabilizing brace is installed to connect the stabilizing hoop and the main load-bearing steel beam; a cap beam secondary joist is laid on the main load-bearing steel beam; a film-coated multilayer board is laid on the cap beam secondary joist as the beam bottom formwork; a protective frame is erected on the cap beam secondary joist.

[0006] S2. Overall Lifting: Erect the operating frame and install the movable hoist to the predetermined height of each pier; use an electric hoist to perform a trial lift through the lifting ring on the movable hoist, lift it a certain distance and then lower it, repeat this several times, and after confirming that there are no errors, lift it to the predetermined position as a whole;

[0007] S3. Scaffold prestressing: After the overall lifting and placement and joint acceptance, the scaffold prestressing is carried out according to the design requirements. After passing the test, the cap beam reinforcement is tied, the prestressed sleeve is constructed, the side formwork is erected and reinforced, and the cap beam concrete construction is carried out after passing the acceptance test.

[0008] S4. Removal of side formwork: After the concrete strength of the cap beam reaches the design tension strength, the prestressing tendons are tensioned. After the concrete strength reaches 100% of the design strength, the side formwork is removed.

[0009] S5. Step-by-step descent: After the bottom formwork is removed and loosened, the entire support system is slowly lowered. The movable hoist is installed between the lower and upper bearing hoops. An electric hoist is used to lower the entire system a certain distance using the lifting rings on the movable hoist. Then, the movable hoist is moved to a position slightly above the top elevation of the main load-bearing steel beam. The entire system is lowered a certain distance again using the lifting rings on the movable hoist. The movable hoist is then moved between the lower and upper bearing hoops. This process is repeated until the system is lowered to the ground.

[0010] S6. Dismantling of Support System: Dismantle the support system.

[0011] Preferably, the stabilizing hoop, lower bearing hoop, upper bearing hoop, and movable hoop are all column hoops made of bent steel plates, and the column hoop is provided with three or more stiffening ribs.

[0012] Preferably, rubber pads are provided between the stabilizing hoop, the lower bearing hoop, the upper bearing hoop, and the movable hoop and the pier column.

[0013] Preferably, in S1, a safety net is hung on the protective frame.

[0014] Preferably, in S2, during the lifting process, the height difference between the two ends of the main load-bearing steel beam is corrected every 1m of lifting, until the height difference Δh between the two ends of the main load-bearing steel beam is ≤10mm and ≤1 / 1000L.

[0015] Preferably, the load-bearing platform is provided with three vertical steel plates, two horizontal load-bearing steel plates and two diagonal bracing steel plates, and five stiffening ribs are provided at the connection points on both sides.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. This invention generates friction by setting column hoops on the outside of the pier column to provide a force point for lifting and support. When lifting, the movable hoop is set in a fixed position, which can realize the support system to be lifted into place in one step. When dismantling, the movable hoop is alternately placed in the upper and lower positions to realize step-by-step descent. At the same time, no foundation treatment is required, which reduces construction costs, reduces a lot of high-altitude work, and the operating frame does not need to be erected again (dismantling pre-embedded conditions are reserved), thus increasing construction efficiency.

[0018] 2. This invention can achieve rapid support and effective reinforcement of double-pier column cap beams. This invention can be assembled on the ground, lifted into place and then fine-tuned, which improves construction efficiency, avoids a lot of high-altitude work, increases construction safety and reliability, and the column hoops, steel beams, diagonal braces, etc. can all be reused, avoiding the foundation treatment process for soft soil foundations, and there is no need to reserve pre-embedded conditions, which reduces construction costs and speeds up construction progress. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure of the double-pier column cap beam support system under the lifting state in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the double-pier column cap beam support system in the descending state in an embodiment of the present invention.

[0021] In the diagram: 1. Pier column; 2. Stabilizing hoop; 3. Lower bearing hoop; 4. Stabilizing column; 5. Main load-bearing steel beam; 6. Upper bearing hoop; 7. Main load-bearing triangular brace; 8. Load-bearing platform; 9. Stabilizing brace; 10. Protective frame; 11. Movable hoop; 12. Lifting ring. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations. Example

[0023] A construction method for a double-pier column cap beam support system involving a one-step lifting and step-by-step lowering, such as... Figure 1 , 2 As shown, it includes the following steps:

[0024] S1. Support System Assembly: Pre-fix (tighten half of the bolts) the stabilizing hoop 2 at the bottom of each pier 1, and pre-fix the lower bearing hoop 3 above the stabilizing hoop 2; install the stabilizing column 4 using M24 ordinary bolts to connect the stabilizing hoop 2 and the lower bearing hoop 3. The stabilizing column 4 is made of 140*60*3 rectangular steel pipe; the main load-bearing steel beam 5 is temporarily fixed to the two pier 1s through the upper bearing hoop 6. Install the main load-bearing triangular brace 7 using M24 high-strength bolts to connect the load-bearing platform 8 on the lower bearing hoop 3 to the main load-bearing steel beam 5. The corresponding friction surfaces are pre-treated to form a stable system.

[0025] M24 ordinary bolts are used to install stabilizing diagonal braces 9, which connect stabilizing hoops 2 to the main load-bearing steel beam 5. Stabilizing diagonal braces 9 are made of 140*60*3 rectangular steel pipes and serve to connect and stabilize the upper and lower systems. Secondary joists for the cap beam are laid on the main load-bearing steel beam 5. The secondary joists for the cap beam are made of 50*100*3 rectangular steel pipes, with a width of about 600mm in the short direction and about 1000mm in the long direction beyond the edge of the cap beam to allow for operation space. A 20mm thick film-coated plywood is laid on the secondary joists for the bottom formwork of the beam. A protective frame 10 is erected on the secondary joists using ø48.3×3.0 steel pipes (with short steel bar ends welded to the secondary joists as fixing points), with a height of 1500mm, and safety nets are hung on the protective frame 10.

[0026] S2. Overall Lifting: Erect an operating frame (with a continuous plank at the bottom), and install the movable hoist 11 to the predetermined height of each pier column 1; use eight 5t electric hoists (four for each pier column, centrally controlled) to perform a trial lift via the lifting rings 12 on the movable hoist 11, lifting 500mm and then lowering, repeating this process three times. After confirming that there are no errors, lift the entire beam to the predetermined position; the top elevation of the main load-bearing steel beam 5 is 120mm below the cap beam, which can be determined according to the template used. During the lifting process, every 1m of lifting, correct the height difference between the two ends of the main load-bearing steel beam 5 (≤30mm) until the height difference Δh between the two ends of the main load-bearing steel beam 5 is ≤10mm and ≤1 / 1000L.

[0027] S3. Scaffold preloading: After the overall lifting and placement and joint acceptance, the scaffold is preloaded according to the design requirements. Preloading can be carried out by using stones, water of the same weight, etc. (soil can also be piled up depending on site conditions). After passing the test, the cap beam reinforcement is tied, the prestressed sleeve is constructed, the side formwork is erected and reinforced, and the cap beam concrete is constructed after passing the acceptance test.

[0028] S4. Removal of side formwork: After the concrete strength of the cap beam reaches the design tension strength, the prestressing tendons are tensioned. After the concrete strength reaches 100% of the design strength, the side formwork is removed.

[0029] S5. Step-by-step descent: (e.g., ...) Figure 2 As shown, after the bottom formwork is removed and loosened, the entire support system slowly descends. A movable hoist 11 is installed between the lower bearing hoist 3 and the upper bearing hoist 6 (approximately 600mm from the lower bearing hoist 3). Eight 5t electric hoists (four for each pier column, centrally controlled) are used to lower the entire structure by 100mm via the lifting rings 12 on the movable hoist 11. The movable hoist 11 is then moved to a position slightly above the top elevation of the main load-bearing steel beam 5. The entire structure is lowered by 100mm again via the lifting rings 12 on the movable hoist 11. The movable hoist 11 is then moved to a position between the lower bearing hoist 3 and the upper bearing hoist 6 (approximately 600mm from the lower bearing hoist 6). This process is repeated until the structure is lowered to the ground.

[0030] S6. Support System Removal: The support system shall be removed and the parts shall be sorted and stacked. Regular inspections shall be conducted, and any defects such as deformation or cracks shall be repaired or replaced in a timely manner for reuse.

[0031] In this embodiment, the stabilizing hoop 2, the lower bearing hoop 3, the upper bearing hoop 6, and the movable hoop 11 are all column hoops made of 20mm thick steel plates. The column hoops are equipped with stiffening ribs (20mm thick steel plates) according to the stress. The upper and lower openings of the column hoops are rounded to avoid scratching the pier column. All of them are fastened with M24 bolts.

[0032] The height of the upper and lower bearing hoops (6, 3) is 600mm. Both are equipped with a load-bearing platform 8 (20mm thick steel plate). The load-bearing platform 8 is equipped with three vertical steel plates, two horizontal load-bearing steel plates and two figure-eight diagonal bracing steel plates, all of which are welded. Five stiffening ribs are set at the connection on both sides.

[0033] The height of the movable hoop 11 is 600mm, and five stiffening ribs are set at each of the two connecting points. The movable hoop 11 is fixed with a lifting ring 12 by a steel plate.

[0034] The height of the stabilizing hoop 2 is 300mm, which mainly plays a role in overall stability. Three stiffening ribs are set at the connection points on both sides.

[0035] A 10mm thick rubber pad is installed between the stabilizing hoop 2, the lower bearing hoop 3, the upper bearing hoop 6, and the movable hoop 11 and the pier column 1 to increase the coefficient of friction.

[0036] The main load-bearing steel beam 5 is made of 36c I-beams, and the main load-bearing triangular brace 7 is made of 30c I-beams. The main load-bearing steel beam 5 and the main load-bearing triangular brace 7, as well as the main load-bearing triangular brace 7 and the load-bearing platform 8, are all connected by 10.9 grade M24 high-strength bolts.

[0037] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structures made using the contents of the present invention specification and drawings, whether directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of the present invention.

Claims

1. A construction method for a double-pier column cap beam support system involving one-step lifting and step-by-step lowering, characterized in that, Includes the following steps: S1. Support system assembly: Pre-fix a stabilizing hoop at the bottom of each pier column, and pre-fix a lower bearing hoop above the stabilizing hoop; install a stabilizing column to connect the stabilizing hoop and the lower bearing hoop; temporarily fix the main load-bearing steel beam to the two pier columns through the upper bearing hoop, and install a main load-bearing triangular brace to connect the load-bearing platform on the lower bearing hoop to the main load-bearing steel beam to form a stable system; Install stabilizing braces to connect the stabilizing hoop to the main load-bearing steel beam; lay the cap beam secondary joists on the main load-bearing steel beam; lay film-coated multi-layer boards on the cap beam secondary joists as beam bottom templates; erect a protective frame on the cap beam secondary joists; hang safety nets on the protective frame; S2. Overall Lifting: Erect an operating frame and install the movable hoist to the predetermined height of each pier column; use an electric hoist to perform a trial lift through the lifting ring on the movable hoist, lift it a certain distance and then lower it, repeat this several times, and after confirming that there are no errors, lift it as a whole to the predetermined position; during the lifting process, correct the height difference between the two ends of the main load-bearing steel beam every 1m until the height difference Δh between the two ends of the main load-bearing steel beam is ≤10mm and ≤1 / 1000L; S3. Scaffold prestressing: After the overall lifting and placement and joint acceptance, the scaffold prestressing is carried out according to the design requirements. After passing the test, the cap beam reinforcement is tied, the prestressed sleeve is constructed, the side formwork is erected and reinforced, and the cap beam concrete construction is carried out after passing the acceptance test. S4. Removal of side formwork: After the concrete strength of the cap beam reaches the design tension strength, the prestressing tendons are tensioned. After the concrete strength reaches 100% of the design strength, the side formwork is removed. S5. Step-by-step descent: After the bottom formwork is removed and loosened, the entire support system is slowly lowered. The movable hoist is installed between the lower and upper bearing hoops. An electric hoist is used to lower the entire system a certain distance using the lifting rings on the movable hoist. Then, the movable hoist is moved to a position slightly above the top elevation of the main load-bearing steel beam. The entire system is lowered a certain distance again using the lifting rings on the movable hoist. The movable hoist is then moved between the lower and upper bearing hoops. This process is repeated until the system is lowered to the ground. S6. Dismantling of Support System: Dismantle the support system; The stabilizing hoop, lower bearing hoop, upper bearing hoop, and movable hoop are all column hoops made of bent steel plates, and the column hoops are provided with three or more stiffening ribs; rubber pads are provided between the stabilizing hoop, lower bearing hoop, upper bearing hoop, and movable hoop and the pier column; the load-bearing platform is provided with three vertical steel plates, two horizontal load-bearing steel plates, and two figure-eight diagonal bracing steel plates, and five stiffening ribs are provided at the connection points on both sides.

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