Steel Formwork Design Essentials

Dec 31, 2024

Steel Formwork Design Essentials

The design of steel formwork comprises every link from material selection all the way to the implementation of specific design plans. This will detail the steps to be led in designing steel formwork.

1. Determine Design Requirements

1.1 Determine the structure type and purpose

The designer must first ascertain what type of structure steel formwork will be used on, such as walls, floors, columns, etc. Different types of structures offer different requirements for formwork; for example, floor formwork must sustain a larger uniform load while column formwork must consider higher pressure.

1.2 Setting the conditions for concrete pouring

Understanding the specific pressure applied to concrete (usually 80-100 kN per square meter) and the specific conditions of pouring (like unit pouring volume, speed of pouring, etc.) are also necessary, These factors form the basis for the parity strength and stability requirements of the material for the formwork design.

2. Material Selection

2.1 Selection of steel

Choose the appropriate steel type with regard to project requirements. Generally, high-strength low-carbon or alloy steel is most often employed for formwork, owing to its good corrosion resistance and high strength. Commonly used steels include Q235, Q345, etc.

2.2 Anticorrosion treatment

Since steel formwork needs to be used for a long time in the external environment, anti-corrosion measures need to be considered in the design. Common anti-corrosion methods include:

· Hot-dip galvanizing: enhances the corrosion resistance of steel formwork and prolongs its service life.

· Coating protection: Use anti-rust coatings (such as epoxy resin coatings) to increase the protective layer of the formwork.

3. Design The Size And Shape Of The Template

3.1 Determine the size of the template

· Dimension design of steel formwork directly affects ease of stripping and transportation of the forms. The size of formwork shall be determined combining factors such as structural measurements, volume of the concrete to be placed, and transportation restrictions.

· The standard template size is usually 1m × 1.2m, 1m × 2m, etc. Depending on the requirements of the specific structural design, the size of the template may need to be adjusted.

3.2 Designing the shape of the template

The form for which the formwork is designed is dependent upon the specific configuration of the structure, such as rectangular, circular, and sloped. Steel currently can assume straight or curved forms, and complex shapes can be executed simply by combining a few more modules.

4. Calculate Load And Safety

4.1 Load analysis

Assess the loads endured by the steel column mold in the process of pouring concrete, such as the weight of concrete, workers, construction equipment, and any other form of added loading. The analysis of the application of structural mechanics should be made to ensure that the formwork could take these pressures.

4.2 Computing support system

The support system of the formwork (such as struts, pillars, and tie rods) must be designed with load distribution and stability in mind. In general, the support structure of the steel formwork system must meet the following requirements:

Bearing Capacity: The prop system shall be sufficiently strong to support the loads exerted by formwork and concrete.
Stability: The prop system should be stable enough to prevent the formwork from climbing or deforming during the placing of concrete.

5. Design Template Connection And Fixing System

5.1 Formwork board connection

· The plates are connected by means of connectors (like bolts, clamps, etc.). At the design stage, connector selection and disposition should be supported by a deal that coordinates to enable the formwork plates not to move or deform during pouring. Common means of connection are:

· Bearing Capacity: The prop system shall be sufficiently strong to support the loads exerted by formwork and concrete.

· Stability: The prop system should be stable enough to prevent the formwork from climbing or deforming during the placing of concrete.

5.2 Fixing system design

The fixing system of steel formwork usually includes:

· Tie rod: used to fix the formwork laterally to prevent the formwork from expanding or moving due to concrete pressure.

· Support column: Provide vertical support to ensure that the formwork does not tilt or sink.

· Wing nut: used to fix the tie rod to ensure the stable connection between the tie rod and the template.

6. Template Surface Treatment And Demoulding Design

6.1 Surface treatment design

In order to ensure that the surface of the steel formwork is smooth and avoid concrete adhesion, surface treatment is usually required. Common surface treatment methods include:

· Coating treatment: The inner surface of the formwork is coated (such as applying a release agent) to prevent concrete adhesion.

· Sandblasting or shot blasting: improve the surface roughness of the formwork and increase the adhesion of concrete.

6.2 Mold release design

The demoulding design of the steel formwork should ensure that the formwork can be easily removed after the concrete solidifies. When designing, it is necessary to select a suitable release agent and arrange the contact surface between the formwork and the concrete reasonably to reduce adhesion.

7. Design For Reusability And Durability

7.1 Reuse

A key goal of steel formwork design is to be able to be reused multiple times. The design should ensure the strength and durability of the formwork to withstand more than 50 cycles of use. Consider the durability of the connectors, support system and the formwork itself.

7.2 Formwork Storage and Transportation

As steel formwork is usually heavy, a system needs to be designed to facilitate storage and transportation. For example, modular design allows formwork panels to be stacked efficiently, reducing transportation costs.

8. Security And Compliance Checks

8.1 Safety Standards

The design of steel formwork must follow relevant safety standards to ensure that the formwork will not fail during pouring due to excessive load or improper connection. Especially in high-rise buildings or complex structures, the formwork design must take into account a higher safety factor.

8.2 Compliance

The formwork design needs to comply with local building codes and standards, such as concrete construction safety specifications, building structure design specifications, etc.

9. Production And Construction

Once the design is completed, the production of steel formwork usually includes:

· Material cutting and welding: Cut and weld the template panels according to the design drawings.

· Surface treatment and assembly: Carry out surface anti-corrosion treatment and assemble each component according to design requirements.

Through the above design steps, the steel formwork can not only ensure the safety and stability during the construction process, but also improve the construction efficiency through good structural design, and ensure the feasibility and economy of multiple uses.

Summarize

The design of steel formwork is a systematic project, involving multiple links from demand analysis to production and construction. Through a scientific design process, it can be ensured that the formwork has sufficient strength, durability and reusability while bearing the concrete load.

During the design process, clarifying project requirements, rationally selecting materials, accurately calculating loads, and optimizing connection and fixing systems are the keys to success. At the same time, surface treatment and demoulding design can significantly improve construction efficiency and the quality of the concrete surface. Modular design not only improves the adaptability of the formwork, but also reduces transportation and storage costs.

Throughout the design and construction process, strict compliance with safety standards and building codes is the prerequisite for ensuring the safety and reliability of the steel formwork system. By optimizing the details of each link, steel formwork design can not only improve construction efficiency, but also reduce long-term costs, ultimately providing important guarantees for the smooth completion of the construction project.

FAQ

What are the common sizes of steel formwork design?

Common sizes of steel formwork are 1m×1.2m, 1m×2m, etc., and can also be customized according to project requirements.

How to ensure the safety of steel formwork?

Steel formwork design should follow local building regulations, calculate safety factors, and select high-quality connectors and support systems. The stability and bearing capacity of the formwork need to be strictly checked during construction.

What is the service life of steel formwork?