Adjustable Steel Prop

Adjustable Steel Prop is a type of steel structural component used for temporary load-bearing, formwork support, or structural reinforcement in construction. It adapts to different height or span requirements through its telescopic adjustment function, featuring high strength, good stability, and reusability. It is widely applied in scenarios such as concrete pouring formwork support, foundation pit bracing, and temporary fixing of steel structures.

I. Structural Composition

An adjustable steel prop typically consists of the following core components, with an overall modular design:

Outer Tube (Fixed Tube): Usually a thick-walled seamless steel tube (e.g., Φ60mm, Φ76mm, etc.), serving as the main load-bearing structure of the prop. A steel plate base is often welded to the bottom to expand the force-bearing area and prevent settlement.

Inner Tube (Telescopic Tube): With a diameter slightly smaller than the outer tube, it can slide into the outer tube. A U-shaped bracket is welded to the top for supporting formwork, section steel, etc.

Adjusting Device:

Threaded Adjustment is common: The outer wall of the inner tube or the top of the outer tube is equipped with threads, which cooperate with nuts (such as top bracket nuts, bottom bracket nuts) to achieve fine length adjustment (adjustment range is usually 300-600mm).

Some models adopt pin hole adjustment: Multiple sets of pin holes are preset on the inner and outer tubes, and the telescopic length is fixed by inserting pins, suitable for large-span rough adjustment.

II. Working Principle

By adjusting the relative position of the inner and outer tubes and locking the length with adjusting devices (threads or pin holes), both ends of the steel prop are respectively pressed against the upper load (such as formwork, beams) and the lower foundation (such as the ground, floor slab), forming a rigid support system. This transfers the upper load to the foundation, preventing structural deformation or collapse.

For example: During concrete pouring, the adjustable steel prop supports the formwork through the top bracket, bearing the self-weight of concrete and construction loads. After the concrete reaches the required strength, the prop can be removed by reversing the adjustment device, enabling cyclic reuse.

III. Core Features

Flexible Adjustment: The length can be precisely adjusted according to construction needs (with an error usually ≤5mm), adapting to different floor heights (e.g., common range of 2.5m-4.5m) or complex terrains, reducing on-site processing procedures such as cutting and welding.

High Load-Bearing Capacity: Made of Q235 or Q355 steel, a single prop can bear 5-30 tons (depending on pipe diameter, wall thickness, and adjustment length), meeting most construction load requirements.

Easy Installation: No professional tools are needed; telescoping and locking can be completed manually, with an erection efficiency over 50% higher than traditional wooden props.

Reusability: The steel structure is wear-resistant and corrosion-resistant (some with galvanized surface treatment), and can be reused more than 30 times under normal maintenance, reducing construction costs.

High Safety: The prop has good stability without the risk of brittle fracture. Moreover, it locks firmly after adjustment and is not easy to loosen due to vibration or load changes.

IV. Main Specifications and Classifications

Classified by Purpose:

Formwork Support: Equipped with a U-shaped bracket on the top, used to support formwork for floors and beams, with common lengths of 2-6m.

Foundation Pit Support: With a larger pipe diameter (e.g., over Φ100mm), used for lateral support of foundation pit slopes or enclosure structures, with lengths up to 10m or more.

Temporary Load-Bearing Support: Used for temporary fixing of components during steel structure installation, which can be combined with diagonal braces to enhance stability.

Classified by Adjustment Method:

Single-Adjustment Steel Prop: Only the top or bottom is adjustable (e.g., only the top bracket has threads).

Double-Adjustment Steel Prop: Both the top and bottom are adjustable, with a wider application range.

V. Application Scenarios

Formwork support systems for building floors, beams, and columns;

Initial support or temporary load-bearing in subway and tunnel construction;

Temporary fixing of components during steel structure factory installation;

Reinforcement support for existing structures in old house renovation;

Bottom formwork support during bridge precast beam pouring.

VI. Usage Notes

Inspection: Before use, ensure the steel tube is free of bending and cracks, the threads are not rusted or damaged, and the base and top bracket are firmly welded.

Vertical Installation: The prop should be as perpendicular as possible to the force-bearing surface (inclination angle ≤5°) to avoid instability caused by eccentric compression.

Load Control: Overloading is strictly prohibited. The load limit of a single prop must be calculated according to the design scheme.

Regular Maintenance: After use, clean the surface of concrete and oil stains, derust and paint rusted parts, and avoid storing them in open air exposed to rain.

With the advantages of high efficiency and durability, adjustable steel props have become the mainstream choice in modern construction, replacing traditional wooden props and steel pipe coupler supports. They can significantly improve efficiency and safety, especially in standardized and large-scale construction.