Abstract: A method of erecting a span between two points is disclosed which comprises the steps of securing an elongated, flexible sheath to the two points; inflating the tubular sheath with a gaseous fluid to form an arched tubular span; maintaining inflation of the arched tubular span to effect a constant pressure differential across the sheath; further increasing the upward force gradient on the sheath by support apparatus; utilizing the arched tubular span as support for a plurality of hollow aluminum troughs; anchoring the troughs at the two end points to erect a permanent load-bearing span between the two end points; and, deflating and removing the tubular sheath.

Abstract: A method of erecting a span between two points, comprising the steps of securing an elongated flexible sheath to the two end points; inflating the sheath with a gaseous fluid to form an arched tubular span connecting the two points; erecting a generally rigid frame structure supported by the tubular span, the frame structure arched at the two end points; utilizing the frame structure as support to erect a span between the two points; permanently anchoring the span at the two end points; and, removing the sheath.

Abstract: A span construction having longitudinal cables extending between end supports, a flexible sheath enclosing the volume bounded by cables and end supports, a fan for forcing a gas through the sheath and gas escape holes on the underside of the sheath to raise the span in response to escaping gas. The span may have an airfoil cross-section so that it is raised in response to cross wind loading.