Spacing rule for vertical (transverse) stiffeners in a plate girder: if d is the clear distance between flange angles (web depth), the spacing should be limited to what range?

Introduction / Context:
Transverse stiffeners subdivide the plate girder web into panels and must be spaced to control shear buckling while avoiding unnecessarily close placement that complicates fabrication.

Given Data / Assumptions:

• d = clear distance between flange angles (effective web depth).
• Standard plate girder proportions and mild steel.

Concept / Approach:
A common exam rule-of-thumb limits the maximum spacing to about 1.5 d to prevent excessive panel slenderness, while a minimum spacing of roughly 0.33 d avoids crowding and allows practical connections and access.

Step-by-Step Solution:

Verification / Alternative check:
Check web panel aspect ratio and use shear buckling equations for confirmation; adjust spacing or web thickness accordingly.

Why Other Options Are Wrong:
Smaller maxima like d may be overly restrictive; larger maxima like 2.0 d or 2.5 d risk slender panels; different minima may not reflect customary practice.

Common Pitfalls:
Measuring d as overall depth rather than clear depth; omitting end/bearing stiffeners at supports; failing to align stiffeners with load application points.

Final Answer:
Not greater than 1.5 d and not less than 0.33 d