Assertion: glider's span | /r/CapableOf | minimize the weight of the girder
Facets:
value: for a given load bearing capacity
type: PURPOSE
Source sentences:
text: Generally, the depth of the girder is no less than ​1⁄ 15 the span, and for a given load bearing capacity, a depth of around ​1⁄ 12 the span minimizes the weight of the girder.