 Morandi's cable-stayed bridges are characterised by very few stays, often as few as two per span, and often with the spans constructed from prestressed concrete rather than the more-usual steel.Although these bridges are often impressive, they are less economic than bridges with multiple stays and have therefore been of little influence on other engineers.Bridges by Morandi have proved to require extensive maintenance and repairs over the years to pass bridge safety inspections, and cables embedded in concrete are difficult to inspect.