Self-anchored suspension bridge

Self-anchored suspension bridge

The main span of the eastern span of the San Francisco–Oakland Bay Bridge, the largest example of a self-anchored suspension bridge in the world.
Ancestor	Suspension bridge
Related	None
Descendant	None
Carries	Pedestrians, automobiles, trucks, light rail
Span range	Medium
Material	Steel rope, steel eye-bar, concrete spar, post-tension-ed concrete deck
Movable	No
Design effort	high
Falsework required	Usually

A self-anchored suspension bridge is a suspension bridge type in which the main cables attach to the ends of the deck, rather than directly to the ground or via large anchorages.^[1] The design is well-suited for construction atop elevated piers, or in areas of unstable soils where anchorages would be difficult to construct.

• Difference between types of bridges
• 
  Suspension bridge with the main cables attached to the ground (black squares)
• 
  Self-anchored suspension bridge; the main cables are attached to the end of the road deck (horizontal blue line)

The load path of the self-anchored suspension (SAS) bridge converts vertical loads into tension forces in the main cables which are countered by compressive forces in the towers and deck. The system balances forces internally without external anchorage requirements, making it suitable for sites where large horizontal forces are difficult to anchor. This is similar to the method used in a tied-arch bridge where arch member compression is balanced by tension in the deck.