Long Span Steel Structure Workshop — Clear Spans to 40 m Clear span 12–40 m Crane 1–300 t Eave height 9–18 m CE & EN 1090-1 Span is the first number that decides what a long span steel structure workshop costs. Doubling the clear span does not double the steel; it multiplies the bending moment, the rafter depth and the crane runway. This page sets out where the limits are, and what changes when a building goes past 30 m. Why Span Drives the Steel Tonnage A member carrying a