Web area definition in a rolled steel beam (I- or H-section) How is the gross cross-sectional area of the web of a steel beam defined for basic calculations?

Introduction / Context:
In preliminary steel design and section property checks, we often separate the web and flange contributions. Knowing the correct expression for the gross web area helps in assessing shear capacity, weld sizing to web, and estimating self-weight and material usage accurately.

Given Data / Assumptions:

• Rolled I- or H-section (beam) with a single web of uniform thickness over the clear depth between fillets.
• “Depth of the beam” refers to the overall section depth typically used for a gross area estimate.
• Flanges are considered separately from the web.

Concept / Approach:
The web is the vertical plate joining the two flanges. To a first approximation, its gross area is the overall depth multiplied by the nominal web thickness (neglecting minor fillet adjustments). This convention aligns with handbook calculations where the web area is treated independently from flange areas.

Step-by-Step Solution:

Verification / Alternative check:
Standard steel tables partition total area into web area plus two flange areas, where the web portion is shown as d * t_w to a close approximation.

Why Other Options Are Wrong:
Flange width × web thickness ignores depth; sum with flange width double counts and is not an area; half depth × thickness underestimates; flange area minus web area is not a definition.

Common Pitfalls:
Confusing clear web depth (between fillets) with overall depth; mixing flange and web contributions; overlooking taper in some rolled sections (still negligible for basic estimates).

Final Answer:
Depth of the beam multiplied by its web thickness