Steel Structure Basics

Introduction to Steel Structures

Steel structures are integral to modern construction, known for their strength, durability, and versatility.

What is a Steel Structure?

A steel structure is a system of interconnected components designed to carry loads safely. It transfers forces like gravity, wind, and seismic activity down to the foundation.

The load-bearing skeleton of a building.

Key Advantages of Steel

  • High Strength-to-Weight Ratio — lighter yet stronger structures.
  • Speed of Construction — prefabricated parts save time.
  • Durability — resistant to aging, insects, and rot.
  • Adaptability — easy future modifications.
  • Sustainability — fully recyclable material.

Common Steel Structural Members

Click on a member to learn more.

W-Shape
HSS
Channel
Angle
Select a member to view its details

Fabrication & Erection Workflow

Understand the five key steps in building a steel structure.

1

Design & Detailing

2

Fabrication

3

Logistics

4

Erection

5

Finishing

Essential Connection Types

Connections are critical in steel structures, ensuring that individual members work together as a cohesive system. The two primary methods are bolting and welding.

Bolted Connections

Bolted connections involve joining steel members using high-strength bolts. Holes are drilled or punched into the members, and bolts are inserted and tightened. This method is common for field connections due to its speed and ease of inspection.

  • Advantages: Faster installation, less specialized labor, easier disassembly/modification.
  • Disadvantages: Larger connection plates, potential for slip or loosening over time.
  • Common Use: Beam-to-column connections, truss connections, field splices.

Welded Connections

Welded connections create a monolithic bond between steel members by melting the metal along the joint and allowing it to fuse. Welding is often used for shop fabrication due to controlled environments, producing strong and aesthetically clean joints.

  • Advantages: High strength, rigidity, clean appearance, no holes needed.
  • Disadvantages: Requires skilled labor, susceptible to temperature changes, difficult to modify.
  • Common Use: Column base plates, plate girder fabrication, moment connections.

Often, a combination of bolted and welded connections is used in a single project to leverage the benefits of both methods.

Design Principles & Industry Standards

Designing with steel requires adherence to rigorous engineering principles and industry-leading standards to ensure safety, efficiency, and structural integrity.

Key Design Considerations

Structural engineers meticulously analyze several factors to create a safe and efficient steel design.

Load Analysis: Determining all forces acting on the structure (dead, live, wind, seismic).
Material Properties: Selecting appropriate steel grades (e.g., ASTM A992) based on strength and ductility.
Stability: Ensuring the structure resists buckling and overturning.
Deflection Control: Limiting deformation under load for serviceability.
Connection Design: Ensuring connections safely transfer forces between members.

American Institute of Steel Construction (AISC)

AISC is the cornerstone of steel design and construction in North America.

AISC Specification & Manual

The AISC Specification for Structural Steel Buildings provides unified requirements for steel design and construction. The AISC Steel Construction Manual offers design aids, tables, and examples to simplify practical applications.

Adherence to AISC standards is essential for legal compliance and structural safety.