Selection of Bridge Type

Span vs Deck Type

• Up to 20m
  Insitu reinforced concrete.Insitu prestressed post-tensioned concrete.Prestressed pre-tensioned inverted T beams with insitu fill.

• 16m to 30m
  Insitu reinforced concrete voided slab.Insitu prestressed post-tensioned concrete voided slab.Prestressed pre-tensioned M and I beams with insitu slab.Prestressed pre-tensioned box beams with insitu topping.Prestressed post-tensioned beams with insitu slab.Steel beams with insitu slab.

• 30m to 40m
  Prestressed pre-tensioned SY beams with insitu slab.Prestressed pre-tensioned box beams with insitu topping.Prestressed post-tensioned beams with insitu slab.Steel beams with insitu slab.

• 30m to 250m
  Box girder bridges - As the span increases the construction tends to go from 'all concrete' to 'steel box / concrete deck' to 'all steel'.Truss bridges - for spans up to 50m they are generally less economic than plate girders.

• 150m to 350m
  Cable stayed bridges.

• 350m to ????
  Suspension bridges.