Steel frames are one of the most common structural systems in modern construction. By using steel beams and columns to create a strong framework, they offer the strength and durability needed for many types of buildings, from garages and workshops to large commercial spaces. Different types of steel frames are suitable for different building applications. Each system is designed to meet specific structural requirements. The best choice depends on the building's purpose, size, and local conditions. For example, a small storage building and a large warehouse often require very different structural designs. In this guide, you'll learn about the main types of steel frames and how each one is used in different building projects.
Common Types of Steel Frame
Steel frame systems can be designed in different ways depending on building size, load requirements, span needs, and construction goals. Each system has unique structural characteristics that affect strength, flexibility, construction speed, and cost.
Portal Frame Structure
A portal frame is one of the most common steel frame types for low-rise buildings. It consists of steel columns and roof rafters connected by rigid joints, allowing the entire frame to work together as one structure.
Because portal frames provide large open spaces with fewer internal columns, they are widely used for buildings that require flexible layouts and efficient construction.
Key Features:
- Uses connected steel columns and roof rafters.
- Creates large clear-span spaces with fewer internal supports.
- Transfers building loads through rigid frame connections.
- Suitable for low-rise buildings with open layouts.
Advantages:
- Uses steel efficiently and helps reduce material costs.
- Allows fast fabrication and installation.
- Makes future expansion easier.
Portal frame systems are commonly used for steel warehouses, manufacturing workshops, logistics centers, agricultural buildings, and storage facilities.
Rigid Frame Structure
A rigid frame system consists of steel beams and columns connected with moment-resistant joints. These connections allow the frame to resist vertical loads and horizontal forces, providing strong stability and design flexibility.
Compared with simpler framing systems, rigid frames provide greater structural strength and are suitable for buildings with higher loads or more complex designs.
Key Features:
- Uses strong beam-to-column moment connections.
- Provides resistance against lateral movement.
- Supports complex building layouts.
- Can be designed for multi-story structures.
Advantages:
- Provides excellent structural stability.
- Offers greater freedom for architectural design.
- Supports heavier loads and demanding projects.
- May reduce the need for additional bracing.
Rigid frame systems are commonly used for commercial buildings, industrial facilities, multi-story steel structures, and other types of steel structure projects requiring higher structural performance.
Braced Frame Structure
A braced frame system uses additional diagonal steel members to improve structural stability. The braces work together with beams and columns to resist horizontal forces caused by wind and earthquakes.
This system improves lateral strength while using steel efficiently, making it suitable for buildings that require additional support against external forces.
Key Features:
- Uses diagonal, X-shaped, or other bracing members.
- Improves resistance to wind and seismic forces.
- Provides efficient structural performance.
- Can be combined with different steel frame layouts.
Advantages:
- Provides reliable performance in high-wind and seismic areas.
- Improves overall building stability.
- Can reduce steel usage compared with fully rigid systems.
Braced frame systems are commonly used for industrial plants, high-rise buildings, warehouses in challenging environments, and structures requiring additional lateral stability.
Truss Frame Structure
A steel truss frame system uses multiple steel members arranged in triangular patterns. This geometric design provides high strength while reducing structural weight, making it suitable for buildings that require very long spans.
Key Features:
- Uses multiple connected steel members instead of large solid beams.
- Creates long spans with fewer internal supports.
- Distributes loads efficiently through triangular structures.
- Provides a high strength-to-weight ratio.
Advantages:
- Creates large column-free spaces.
- Reduces structural weight while maintaining strength.
- Provides excellent performance for long-span structures.
- Works well for complex roof designs.
Truss frame systems are commonly used for aircraft hangars, stadiums, airports, exhibition halls, and other large-span buildings.
Space Frame Structure
A space frame system is a three-dimensional steel structure made from interconnected members arranged in geometric patterns. Unlike traditional two-dimensional frames, space frames distribute loads in multiple directions.
Key Features:
- Uses three-dimensional steel member arrangements.
- Provides high strength with relatively low structural weight.
- Can cover large areas with fewer supporting columns.
- Offers flexible design options for complex structures.
Advantages:
- Creates wide, open interior spaces.
- Provides efficient load distribution.
- Suitable for complex architectural designs.
Space frame systems are commonly used for stadium roofs, airports, exhibition centers, and large public buildings.
Light Gauge Steel Frame (LGSF)
Light gauge steel frame systems use thin cold-formed steel sections to create lightweight structures. The components are easy to transport and install, making them suitable for smaller buildings and projects that require fast construction.
Key Features:
- Uses lightweight cold-formed steel sections.
- Allows fast installation with simple tools.
- Requires less heavy lifting equipment.
- Suitable for small and medium-sized buildings.
Advantages:
- Easy to handle and transport.
- Reduces construction time.
- Provides a practical balance of strength and flexibility.
Light gauge steel frames are commonly used for residential buildings, accessory structures, offices, and light commercial projects.
Heavy Structural Steel Frame
Heavy structural steel frame systems use large steel members such as hot-rolled H sections and fabricated box columns. They are designed for projects requiring high load capacity, long spans, and strong structural performance.
Key Features:
- Uses large steel sections for major structural loads.
- Provides high strength and stiffness.
- Supports heavy equipment and large buildings.
- Suitable for demanding construction conditions.
Advantages:
- Handles heavy loads effectively.
- Provides excellent structural durability.
- Suitable for large-scale construction projects.
Heavy structural steel frames are commonly used for high-rise buildings, power plants, industrial facilities, and large infrastructure projects.
Modular Steel Frame
A modular steel frame system uses factory-built three-dimensional modules that are transported to the construction site and connected. The modules may include structural frames, walls, finishes, and building systems before installation.
Key Features:
- Uses prefabricated three-dimensional modules.
- Completes most construction work in a factory environment.
- Reduces on-site installation time.
- Improves construction quality control.
Advantages:
- Shortens overall construction schedules.
- Reduces on-site labor requirements.
- Provides consistent manufacturing quality.
Modular steel frame systems are commonly used for hotels, dormitories, apartment buildings, temporary facilities, and rapid construction projects.
How to Choose the Right Steel Frame Type
The best steel frame type depends on several factors, including building use, space requirements, location, budget, and future plans. Different conditions require different structural solutions.
Building Use
The purpose of the building affects the required space, strength, and layout.
- Warehouses, workshops, and storage buildings: Portal frame structures are often suitable because they provide large open spaces with efficient steel usage.
- Aircraft hangars: Truss frames or space frames are preferred because they can create wide, column-free areas.
- Multi-story commercial buildings: Rigid frames or braced frames are commonly used for higher strength and stability.
Building Size and Span Requirements
The required span and interior space affect which frame type can provide the best performance.
- Medium-span buildings with open layouts: Portal frames are a cost-effective choice.
- Very large-span structures requiring fewer columns: Truss frames or space frames are more suitable.
- Buildings requiring flexible layouts or higher load capacity: Rigid frames can provide better structural performance.
Location and Environmental Conditions
The project location can influence the required level of structural stability.
- Areas with strong winds or earthquakes: Braced frames or rigid frames are often preferred for better lateral stability.
- Coastal areas with high humidity or salt exposure: Steel frames with additional corrosion protection are recommended.
- Regions with heavy snow loads: Frames should be designed to support higher roof loads.
Construction Timeline
The required construction speed can affect the choice of steel frame type.
- Projects requiring fast installation: Pre-engineered portal frames are commonly used because components can be fabricated in advance.
- Projects with very short construction schedules: Modular steel frames can reduce on-site work.
Budget Requirements
The project budget affects the balance between cost and structural performance.
- Cost-effective warehouses and workshops: Portal frames are often selected because of efficient material use.
- Projects requiring unique designs or very long spans: Truss or space frames may require higher investment but provide better solutions.
Future Expansion Needs
Future plans should be considered before selecting a frame type.
- Buildings that may need extensions later: Portal frame buildings are often easier to expand by adding additional bays.
- Buildings with changing functional requirements: Flexible frame designs can make future modifications easier.
The best steel frame system is the one that matches your building requirements, operating conditions, and long-term goals. A professional structural analysis can help determine the most efficient solution while balancing safety, performance, and construction costs. Choosing the right type of steel structure is an important part of achieving the best overall building performance.
If you need help choosing the right steel frame system, CNSS is here to help. Contact us to learn more about our steel building solutions.
