What is Bridge?
A bridge is a structure that spans horizontally between supports and is used to carry vertical loads. Even though the prototypical bridge is quite simple—two supports holding up a beam—even in this simplified form, every bridge has achieved engineering challenges. The supports must be strong enough to support the structure, and the span between the supports must be strong enough to support the loads. Long spans are justified when good foundations are scarce, such as over estuaries with deep water and generally kept as short as possible