Steel supports are widely used in various construction projects such as building formwork support, subway deep foundation pit support and bridge engineering. As a reusable load-bearing component, scientific and standardized disassembly and reuse can not only reduce engineering costs, but also reduce resource waste and conform to the concept of green and sustainable construction. However, the disassembly and reuse of steel supports involve strict safety norms and technical requirements. Improper disassembly may lead to structural deformation, safety accidents, and improper reuse may reduce the load-bearing capacity of steel supports, affecting the safety of subsequent projects. Therefore, it is necessary to strictly follow the standardized methods to carry out the disassembly and reuse work.
The disassembly of steel supports must adhere to the core principles of "safe, orderly, gradual and controllable", and the disassembly work can only be carried out when the conditions for disassembly are met. The premise of disassembly is that the supported structure (such as concrete, steel structure) has reached the design strength and can independently bear the load, and the load on the steel supports has been completely transferred to the permanent structure. For example, in subway deep foundation pit construction, steel supports can only be disassembled after the foundation slab, side wall and other structures are poured and their strength reaches more than 75% of the design strength; in formwork support construction, disassembly can be carried out only after the concrete curing period is completed and the strength meets the requirements of the specification. Before disassembly, it is necessary to conduct a comprehensive inspection of the construction site and the steel supports themselves to confirm that there is no potential safety hazard, and formulate a detailed disassembly plan, including the disassembly sequence, operation steps, safety protection measures and emergency plans.
The standard disassembly process of steel supports is divided into four stages: pre-disassembly preparation, load transfer and unloading, step-by-step disassembly, and transportation and stacking.
In the pre-disassembly preparation stage, first, the construction personnel must be organized to conduct technical and safety disclosure, clarifying the disassembly sequence, operation points and safety precautions, and all operators must be professional and hold relevant operation certificates. Second, it is necessary to prepare the required tools and equipment, including wrenches, hydraulic jacks, cutting tools, hoisting equipment, safety protection equipment (safety helmets, safety belts, anti-skid shoes, etc.), and check the performance of the tools to ensure they are in good condition. Third, the disassembly area should be isolated, safety warning signs should be set up, and special personnel should be arranged to guard to prevent irrelevant personnel from entering the operation area. In addition, it is necessary to check the steel supports to be disassembled, and mark the damaged, deformed or corroded props in advance to avoid mixing them into the subsequent reuse links.
The load transfer and unloading stage is the key to ensuring the safety of disassembly, and it is strictly prohibited to disassemble the steel supports directly without unloading. For steel supports with prestress (such as subway foundation pit supports), the prestress should be gradually released first. The release process should be slow and uniform, and the unloading speed should be controlled to avoid sudden release of stress leading to structural deformation or vibration. Hydraulic jacks can be used to assist in unloading: place the jacks between the steel support and the supported structure, slowly jack up the structure to transfer the load from the steel support to the jack, then gradually loosen the locking mechanism of the steel support, and slowly lower the jack to complete the load transfer. For ordinary formwork steel supports, the load can be transferred by gradually adjusting the telescopic mechanism of the props, and the adjustment process should be slow, and the structural deformation should be observed at any time. If abnormal deformation, cracking or other phenomena are found, the operation should be stopped immediately, and the problem should be solved before continuing.
In the step-by-step disassembly stage, the disassembly sequence must be strictly followed, and "from top to bottom, from inside to outside, symmetric and synchronous" is the basic principle. For the steel support system with horizontal bracings and diagonal bracings, the diagonal bracings should be disassembled first, then the horizontal bracings, and finally the vertical steel supports, to avoid the overall instability of the support system caused by disassembly in the wrong order. For large-span or multi-point support systems, the disassembly should be carried out symmetrically and synchronously, and the disassembly speed of each support point should be consistent to prevent uneven stress and structural tilting. When disassembling a single steel support, first loosen the connection between the prop and the base, top plate or steel purlin, then adjust the telescopic mechanism to reduce the length of the prop, and then hoist it to the designated area with hoisting equipment. It is strictly prohibited to throw the steel support directly to the ground to avoid damage to the prop and safety accidents. For steel supports that are difficult to disassemble due to rust or deformation, appropriate tools can be used to assist in disassembly, but it is strictly prohibited to use violent disassembly methods such as cutting or knocking, which will damage the structural integrity of the props.
In the transportation and stacking stage, the disassembled steel supports should be transported to the designated stacking area in a timely manner. The transportation process should be stable to avoid collision, extrusion and other phenomena between the props, which will cause deformation or damage to the tube body, thread or locking mechanism. When stacking, the steel supports should be classified according to their specifications, models and damage status, and placed neatly. The stacking height should not exceed 1.5m to avoid collapse caused by excessive stacking. The stacking site should be flat, dry and well-drained, away from corrosive media and open areas exposed to wind and rain, to prevent corrosion of the steel supports during storage.
The reuse of steel supports must be based on strict inspection and necessary treatment to ensure that the performance of the props meets the requirements of subsequent engineering use. The core of reuse is "inspection first, treatment second, and qualified before use", which can effectively avoid safety hazards caused by unqualified props.
The pre-reuse inspection of steel supports is a key link, which mainly includes appearance inspection, size inspection, performance test and anti-corrosion performance inspection. In terms of appearance inspection, it is necessary to check whether the steel support has deformation, cracks, wear, rust and other defects: the tube body should be free of obvious bending, deformation and cracks, the thread part should be smooth and free of wear and deformation, the locking mechanism should be flexible and reliable, and the base and top plate should be intact without damage. In terms of size inspection, the length, tube diameter, wall thickness and other parameters of the steel support should be measured to ensure that they are consistent with the design requirements of the subsequent project. In terms of performance test, for steel supports used in heavy-load scenarios (such as subway foundation pit support), load-bearing performance tests should be carried out to verify whether their rated load-bearing capacity meets the requirements; for props with welding parts, the welding quality should be inspected to avoid welding defects such as cracks and incomplete penetration. In terms of anti-corrosion performance inspection, check the integrity of the anti-corrosion layer (such as zinc layer, paint layer), and if there is damage, peeling or corrosion, corresponding treatment is required. According to relevant standards, only steel supports that pass all inspection items can be put into reuse; unqualified props should be scrapped or repaired, and reused only after passing the re-inspection.
For steel supports that pass the inspection, corresponding treatment should be carried out according to their actual status to restore their performance and extend their service life. For props with slight rust, mechanical polishing or derusting agents can be used to remove the rust, and then anti-corrosion treatment (such as painting, zinc spraying) can be carried out to isolate the corrosive media. For props with worn threads, thread repair or replacement of the thread part can be carried out to ensure flexible adjustment and firm locking. For props with slight deformation, professional correction equipment can be used to correct them, and performance tests should be carried out after correction to ensure that they meet the requirements. For the anti-corrosion layer damaged during disassembly and transportation, the damaged part should be repaired in time, and the thickness of the anti-corrosion layer should be ensured to meet the standard requirements. In addition, the steel supports after treatment should be marked with their specifications, inspection date and reuse times to facilitate management and tracking.
When reusing steel supports, it is necessary to select appropriate props according to the requirements of the subsequent project, and strictly follow the installation specifications to ensure the safety and stability of the support system. First, the model and specification of the steel support should be matched with the load-bearing requirements and construction height of the project. It is strictly prohibited to use props with insufficient load-bearing capacity in heavy-load scenarios. Second, when installing the reused steel supports, the installation steps and requirements should be the same as those of new props, including accurate positioning, vertical installation, firm locking, and installation of horizontal and diagonal bracings. Third, during the use process, regular inspection should be carried out to monitor the stress state and structural stability of the steel supports, and timely treatment should be carried out if any abnormal situation is found. Fourth, the number of reuses of steel supports should be controlled. Generally, the number of reuses of ordinary steel supports should not exceed 3-5 times, and the number of reuses of heavy-duty steel supports (such as subway special steel supports) should not exceed 3 times. After reaching the maximum number of reuses, they should be scrapped in time to avoid safety hazards caused by material fatigue.
It should be noted that the disassembly and reuse of steel supports must comply with relevant national and industry standards, such as GB 50205-2020 《Code for Construction Quality Acceptance of Steel Structures》, JGJ 80-2016 《Code for Safety Technology of High-Altitude Operation in Construction》, and EN 1065 (European standard), ASTM A123 (American standard) for international projects. In addition, the disassembly and reuse work should be included in the project construction plan, and the whole process should be recorded, including the disassembly time, number of props, inspection results, treatment measures and reuse situation, to provide a basis for project acceptance and subsequent management. For steel supports used in special scenarios such as subway construction, more strict inspection and treatment standards should be adopted to ensure that they meet the special requirements of the project.
In practical application, the disassembly and reuse of steel supports not only reflect the concept of green construction, but also bring considerable economic benefits to the project. By reusing steel supports, the purchase cost of new props can be reduced, the generation of construction waste can be reduced, and the resource utilization rate can be improved. For example, in a large-scale subway project in Shanghai, the steel supports after the completion of the foundation pit construction were disassembled, inspected and treated, and then reused in the subsequent station structure construction, which not only saved a lot of engineering costs, but also achieved the effect of energy conservation and environmental protection. However, it is necessary to avoid blind reuse for cost saving, and strictly control the quality of reused props to ensure the safety of the project.
References
1. GB/T 7714 Format
China Railway Tunnel Bureau Group Co., Ltd. Disassembly and Reuse Technical Guidelines for Steel Supports[EB/OL]. [2026-04-17].
2. MLA Format
American Galvanizers Association. "Safe Disassembly Methods and Reuse Standards for Steel Supports." American Galvanizers Association, 2026. Accessed 17 Apr. 2026.
3. APA Format
Xinfa Yijian Engineering Co., Ltd. (2026). Quality Control and Operation Norms for Disassembly and Reuse of Steel Supports in Construction Engineering.
4. MLA Format
Brilliance Solution. "How to Remove a Steel Prop Safely?" Brilliance Solution, 2025. Accessed 17 Apr. 2026.
5. APA Format
Steel Construction Institute. (2024). Publication 427 Structural Steel Reuse: Assessment, Testing and Design Principles.