Question: what determines the distancea beam bridge can span

title: Beam bridge
text: Beam bridges are often only used for relatively short distances because , unlike truss bridges , they have no built in supports . The only supports are provided by piers . The farther apart its supports , the weaker a beam bridge gets . As a result , beam bridges rarely span more than 250 feet ( 80 m ) . This does n't mean beam bridges are n't used to cross great distances , it only means that a series of beam bridges must be joined together , creating what 's known as a continuous span . 

Answer: answer: Beam bridges are often only used for relatively short distances because , unlike truss bridges , they have no built in supports. Beam bridges rarely span more than 250 feet. This does not mean beam bridges are not used to cross great distances, it only means that a series of beam bridges must be joined together, creating what 's known as a continuous span .
answer: Beam bridges are supported by piers. The farther apart those piers are, the weaker the bride gets. As a result , beam bridges rarely span more than 250 feet. For a beam bridge to cover a great distance, a series of beam bridges will need to be joined together, creating a continuous span.