Building Additions in Steel : The Architecture of Vertical Extensions

Since the introduction of steel as a building material in the early twentieth century, its superior performance has challenged conventional wisdom about construction, enabling designs of surprising lightness and span. Steel offered the opportunity to significantly expand buildings vertically and thus emerged as a symbol of the conflict between technological progress and the architectural ideal. More recently, the use of exposed steel elements in modern architecture ushered in a rediscovery of buildings' metamorphoses.