The Long Span Railway Bridge Design Controversy

For centuries, wood and stone had been the principal materials used in bridge construction, but from the time of Abraham Darby's Iron Bridge, cast iron, then wrought iron and thereafter steel became increasingly used as construction materials. Although the use of these new materials in lightly trafficked "road" bridges was successful, the railway age was to signal the necessity for stronger bridges to withstand much heavier loads. These problems became acute as railroads spread and engineers started to consider how to construct railway bridges with spans of several hundred feet. Initially two different methodologies were used by two of the most brilliant engineers of the age. John A. Roebling's choice of design was the suspension bridge and his Niagara Bridge is compared with the tubular bridges constructed by Robert Stephenson in the United Kingdom and Canada. Later developments led to other solutions but these two methodologies provide us with a classic study of the state of the art of the Civil Engineering profession at that time.