It depends what kind of, and what style of bridges you want. Here is a few things I have seen used that you could use for model and usable bridges.
wood
plastic hoped this helped
steel
concrete
glass
stone
bricks
string
aluminum
titanium
steel wire
paper
glue
rubber
cardboard
legos
Vines/Rope, Wood, Stone, Brick, Steel, and concrete have all been used to varying success in building bridges.
metal, wood and all sort of materials like that
Most likely it was a fallen tree trunk or limb. So it would be wood.
wood,foam,concrete,metal,screws and bolts
Iron
By Technology developing and also people researching how to make bridges and thinking of new ways to make bridges and new materials to use.
toothpicks, hot glue, and fishing line
bridges have become safer over time with the growing sustainabiltity of materials. The world is becoming more technologically advanced which improves the quality of manufactures. Also the great education system helps more people learn about the right materials to create these bridges, therefore more people know what is best to use and what is safest.
wood
sand and bamboo with some dirt and flowers to make it look pretty and chicken bones (sometimes mistaken as rooster bones) were used, Little pepit was the creator of the bridge. Years later, asian people destroyed it, and threw the bridge at Little pepit house. Little pepit spirit now haunts the asian people, so to be safe, you must wear a cat over your head.
Soft
they use wooden planks
steel
plastic rubber glass metal
Typical clothings
use stronger materials when building overpasses and bridges
use stronger materials when building overpasses and bridges