Selecting the correct structural steel section is critical for strength, stability, and cost efficiency in construction and fabrication projects. Common section types such as UB, UC, RHS, and SHS are widely used across the UK and international markets, yet they are often misunderstood by buyers.
This guide explains the main structural steel sections, how they differ, and how to choose the right option for your project.
Why Structural Steel Section Selection Matters
Structural steel sections determine:
- Load-bearing capacity
- Structural stability
- Material efficiency
- Fabrication and installation costs
Choosing the wrong section can lead to over-engineering, higher costs, or compliance issues, particularly when working to EN standards.
What Is a UB (Universal Beam)?
Universal Beams (UB) are I-shaped sections designed primarily to resist bending loads.
Key characteristics:
- Wide flanges with a relatively shallow depth
- Excellent strength-to-weight ratio
- Efficient for horizontal spans
Typical applications:
- Floor beams
- Roof beams
- Bridges
- Commercial buildings
UBs are commonly supplied in S275 and S355 structural steel grades, depending on design requirements.
What Is a UC (Universal Column)?
Universal Columns (UC) are also I-shaped sections but are designed mainly for vertical load-bearing.
Key characteristics:
- Deeper and heavier than UBs
- Thick flanges and web
- High axial load capacity
Typical applications:
- Columns
- Vertical supports
- Heavy structural frames
UC sections are ideal where compressive strength is critical.
What Is RHS (Rectangular Hollow Section)?
Rectangular Hollow Sections (RHS) are closed, rectangular steel sections offering strength in two axes.
Key characteristics:
- High torsional resistance
- Clean, modern appearance
- Good resistance to buckling
Typical applications:
- Structural frames
- Architectural steelwork
- Industrial structures
- Fabricated components
RHS sections are widely used where aesthetic and structural performance are both important.
What Is SHS (Square Hollow Section)?
Square Hollow Sections (SHS) are closed, square profiles with equal dimensions on all sides.
Key characteristics:
- Uniform strength in all directions
- Excellent torsional rigidity
- Easy to align and fabricate
Typical applications:
- Columns and frames
- Modular construction
- Exposed architectural steel
SHS sections are often chosen for their symmetry and clean design.
UB vs UC vs RHS vs SHS – Key Differences
| Section Type | Primary Use | Strength Characteristics | Common Applications |
|---|---|---|---|
| UB | Bending | High bending resistance | Beams, floors, roofs |
| UC | Compression | High axial load capacity | Columns, supports |
| RHS | Multi-directional | High torsional strength | Frames, structures |
| SHS | Uniform loading | Equal strength on all axes | Columns, architecture |
Each section type serves a specific structural purpose, and correct selection is essential for safety and efficiency.
Structural Steel Sections, Grades & Standards
Structural steel sections in the UK are typically supplied to EN standards, most commonly:
- S275
- S355
- S460
Buyers should ensure compatibility with:
- EN steel standards
- Required certifications (EN 10204 3.1 / 3.2)
- Project-specific compliance requirements
For international projects, buyers may also need to consider ASTM standards and grade equivalency.
How to Choose the Right Structural Steel Section
When selecting a steel section, buyers should consider:
- Load and span requirements
- Structural design calculations
- Fabrication and installation constraints
- Aesthetic considerations
- Applicable standards and certifications
For procurement guidance, buyers may also refer to our steel sourcing guide for UK and international projects.
Common Buyer Mistakes with Steel Sections
Typical issues include:
- Using UBs where UCs are required
- Over-specifying hollow sections
- Ignoring torsional loads
- Failing to align section choice with steel grade
These mistakes often lead to unnecessary costs or design revisions.
How CoreMet Steel Supports Structural Steel Buyers
CoreMet Steel helps buyers by:
- Supplying a full range of structural steel sections
- Advising on section selection and grades
- Ensuring compliance with EN and international standards
- Supporting UK and global supply chains
Our experience helps reduce risk and improve project efficiency.
Industry Standards and Further Guidance
Structural steel design and section standards are governed by organisations such as the British Constructional Steelwork Association (BCSA), which provides guidance on UK steel construction and best practices.
Speak to CoreMet Steel
Choosing the correct steel grade impacts cost, safety, and delivery timelines.
Contact CoreMet Steel for:
- Grade selection advice
- UK & international sourcing
- Competitive quotes with certification
