Definition and Function

A cantilever beam hook is a specialized lifting device used for the hoisting, installation, or temporary fixing of cantilever structures (such as cantilever beams, slabs, and cantilevered work platforms). It is typically used in conjunction with embedded lifting rings, steel wires, and hand chain hoists. Its primary functions include:

1. Load Transfer: The hook transfers the weight of the cantilever component and construction loads to the main structure or lifting equipment (such as a tower crane), ensuring stable and reliable hoisting.

2. Precise Positioning: By cooperating with embedded parts, the hook enables the accurate installation of components, preventing misalignment or tilting.

3. Safety Protection: During cantilever construction, the hook must meet requirements for anti-toppling and anti-slippage to prevent structural damage or accidents caused by hoisting imbalance.

Types and Construction of Cantilever Beam Hooks

Based on engineering requirements, cantilever beam hooks can be categorized into two main types:

1. Fixed Hook:

• Directly welded or bolted to the embedded parts of the cantilever beam/slab, suitable for standardized component hoisting (such as prefabricated composite slabs, steel beams).
• For example, the patent CN218371331U describes a "movable hook" that uses a sliding cap to cooperate with the main beam of a bridge erection machine, expanding the horizontal lifting range and preventing bridge erection machine overturning.

2. Adjustable Hook:

• Composed of combination parts such as U-bolts and hand chain hoists, allowing flexible adjustment of lifting points, suitable for complex conditions (such as irregular components, multi-point coordinated hoisting).
• For instance, the lifting rings of cantilever work platforms are symmetrically arranged, with four lifting points, and the steel wire rope clamps are fixed to ensure even load distribution.

Key Technical Parameters and Design Requirements

The design of a cantilever beam hook must meet the following core parameters:

1. Load-bearing Capacity:

• The rated load of the hook must be ≥1.5 times the weight of the component (including construction loads), and it must be verified through static load testing.
• For example, the uniform load of a cantilever work platform is ≤5.5kN/m², and the concentrated load is ≤15kN, with the hook designed according to these standards.

2. Anchor Length and Connection Method:

• The fixed section length must be ≥1.25 times the cantilever length to ensure anti-toppling stability.
• The node connection must use rigid nodes (such as bolts or welding), and the use of flexible materials like steel pipes is prohibited.

3. Material and Corrosion Prevention:

• The main material is typically Q235B or Q345B steel, and the surface must be hot-dip galvanized or coated with anti-corrosion paint to extend the service life.

Safety Control Points During Construction

1. Lifting Point Arrangement:

• The lifting point of the hook must coincide with the center of gravity of the component to prevent torque during hoisting.
• For example, the lifting hooks of prefabricated walls must be symmetrically arranged to prevent wall rotation and collision.

2. Temporary Fixing Measures:

• After the cantilever beam is installed, temporary supports (such as diagonal braces or independent supports) must be set up immediately to prevent overturning.
• The spacing of the diagonal braces must be ≤1000mm, and the bottom must be reliably connected to the external scaffolding.

3. Inspection and Monitoring:

• Before hoisting, the welds and bolt tightening of the hook must be checked, and photographic evidence must be retained.
• During construction, the deformation of the cantilever structure must be monitored. If it exceeds the allowable value (such as 3‰ of the span), immediate reinforcement is required.

Case Studies and Regulatory References

1. Typical Case Studies:

• In the hoisting of a cantilever steel beam for a high-rise building, a movable hook combined with a hand chain hoist was used to successfully position a steel beam weighing 12 tons, improving hoisting efficiency by 30%.
• In the hoisting of prefabricated PCF slabs, the combination of a universal lifting hook and a hook solved the component rotation positioning problem.

2. Regulatory References:

• The "Safety Technical Code for Cantilevered Scaffolding in Construction" (JGJ130-2011) requires that hooks be designed according to the load and that no fewer than two diagonal braces be set.
• The "Steel Structure Engineering Construction Quality Acceptance Specification" (GB50205-2020) stipulates that the welds of hooks must be 100% ultrasonic tested.

Conclusion and Recommendations

The cantilever beam hook, as a key tool in cantilever construction, directly affects the safety and efficiency of the project. Recommendations include:

• Prioritize the use of standardized hook products (such as patent CN218371331U) to reduce on-site welding risks.
• Strengthen training for construction personnel to ensure the coordinated operation of hooks with steel wires and embedded parts.
• Promote the use of BIM technology to simulate lifting paths and avoid interference between hooks and structures.

By implementing these measures, the application of cantilever beam hooks can be significantly improved, ensuring the safety and economy of cantilever structure construction.

Handan Guocheng Trading Co., Ltd

www.handanguocheng.com