depends on the bridge type really. most are steel and concrete.
There are several important materials required for constructing bridges. The first two of these would be steel and concrete.
what materials are needed to build a lighthouse
toothpicks, hot glue, and fishing line
There are many types of materials engineers use to build walls. Three possible construction materials are wood, brick, and concrete.
All bridges in the Unites States are inspected every two years -- more often if they are critical. Railroads have B & B (bridge and building) engineers who look over the bridges under their charge. Because railroad loadings are larger than highway loads, railroad bridges tend to be stronger than other kinds.
bridge
Skycrapers are usually made up of steel frames with fireproof combination of cast iron columns and beams.
They arent used as much because we have new kinds of bridges that may be more efficient and that are stronger
Accounting
you could build a tiny hut,from long sticks
They build boats and used the rivers as a highway. They used donkeys, cattle and horses too ride and carry goods and draw carts, wagons and sledges. They walked and carried goods.
there are four kinds of volcanoes
pencil