Assertion: tower | /r/HasProperty | built of rolled steel angles
Facets:
value: heretofore
type: TEMPORAL
Source sentences:
text: Heretofore towers of this type have been built of rolled steel angles or the like in which the longitudinal forces caused by the breakage of one or more of the wires are carried down from the cross-arm to the logs of the tower through corner rails and shear bracing placed in the exterior faces of the upwardly tapered, outwardly diverging supporting arms of the tower, which extend in a straight line from the cross-arm plane down to the waist line.