January 15th, 2026

Steel girders and beams make up the primary support system of buildings, bridges, ships, and other large structures. Both are fabricated to transfer weight-bearing force into support columns and down into the foundation, but is there a difference between a girder and a beam, or are these two names for the same thing?

IT ALL BOILS DOWN TO SIZE

The primary difference between a steel girder and a steel beam comes down to size and structural function.

A beam is a horizontal structural member designed to support loads and transfer them to columns or walls. Beams are commonly used throughout a structure and may support floors, roofs, or secondary framing.

A girder is a larger, heavier beam that serves as the main structural support. Girders carry the load of multiple beams and transfer that weight to columns or foundations. In simple terms, all girders are beams, but not all beams are girders.

There is no fixed industry standard that defines when a beam becomes a girder. Instead, the designation depends on how the member is used within the structure and the loads it is designed to carry.

FABRICATION CHALLENGES FOR STEEL GIRDERS AND BEAMS

Both steel girders and beams must be fabricated with high precision. Accurate flange cuts, web openings, copes, and bevels are essential to ensure proper fit-up and structural integrity.

As girder size increases, fabrication becomes more complex. Large sections, thick material, and detailed connection geometry increase the risk of errors when using manual or semi-automated processes. This is where automation plays a critical role.

HOW BEAMCUT IMPROVES FABRICATION

Beamcut improves steel girder and beam fabrication by automating the cutting and beveling of structural steel with a purpose-built robotic plasma system. By replacing manual layout, drilling, sawing, coping, and grinding with a single automated process, Beamcut increases accuracy, consistency, and throughput while reducing handling and errors. Its six-axis FANUC robotic arm performs 360-degree beveling and complex multi-axis cuts on a wide range of structural profiles, while Hypertherm X-Definition plasma and integrated laser measurement ensure clean cuts and precise positioning. Combined with CNC software that validates geometry and cutting paths before production, Beamcut delivers repeatable, high-quality results for both beam and girder fabrication.

WHY BEAMCUT IS IDEAL FOR STRUCTURAL STEEL FABRICATORS

By consolidating multiple fabrication processes into a single robotic system, Beamcut helps structural steel fabricators:

• Reduce labor and material handling
• Improve consistency and accuracy
• Increase throughput and production capacity
• Meet tight project schedules with confidence

Fabricators producing both primary girders and secondary beams benefit from faster processing and fewer downstream corrections.

Click here to learn more about Beamcut.