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Structural

Girder

In Plain English

A large horizontal beam that carries the weight of smaller beams and transfers it to columns.

Definition

A large, primary horizontal structural member that supports beams, joists, or other secondary members. Girders span between columns or walls and carry the accumulated loads from the framing they support. In steel construction, girders are typically wide-flange sections or plate girders fabricated for long spans.

Why It Matters in Bidding

Girders carry the heaviest accumulated loads in a framing system, so their size, weight, and connections drive a large share of structural steel tonnage and fabrication cost in an estimate. Because long-span and plate girders may require special fabrication, shipping, and crane picks, an estimator must account for them separately rather than averaging them into typical beam pricing.

Example

Doing a steel takeoff, the estimator separates the heavy transfer girders carrying the floor above the lobby and prices their fabrication, oversize shipping, and a larger crane pick apart from the typical infill beams.

Related Terms

BeamColumnJoistSpan

Frequently Asked Questions

A girder is a primary member that supports other beams and joists, so it carries larger loads and is heavier per foot. Beams frame into girders. In a takeoff, girders often need separate pricing for connections, fabrication, and erection because their size affects crane selection and handling more than typical infill beams.
Heavier and longer girders increase crane capacity and reach requirements, can demand larger or additional cranes, and may need special rigging or multi-piece lifts. Some long-span girders also trigger oversize transport permits. Estimators price these erection logistics separately because they materially affect equipment cost and schedule beyond raw steel tonnage.
Transfer girders redistribute loads from columns or walls above to a different support line below, so they are unusually deep and heavy and often built up as plate girders. They require more fabrication labor, careful connection design, and heavier picks, making them cost outliers an estimator should isolate rather than blend into typical framing rates.

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