The Spin on Spans
Since ancient times, engineers have built bridges that help humans cross obstacles like streams, valleys, roads and railroad tracks. Bridges are complicated structures that rely on specific elements of engineering to make them successful. To build a bridge, engineers must consider many things. Among those things considered are: the distance to be spanned and the types of materials available. Once these things are considered, an engineer can finally determine the size, shape and overall look of a bridge.