Description

This book presents the developments in bridge building that occurred in the United States toward the end of the eighteenth century and in the beginning of the nineteenth century. With the growing need for bridges and the willingness to invest in such enterprises, American bridge builders were encouraged to be daring and inventive in their design. Their inventiveness led to the development of long-span wooden bridges with laminated members where the laminated members were used not only for major chords but for arched ribs in compression as well. This structural evolution in bridge design culminated with the building of the “Colossus” of Philadelphia, a 340 ft clear span wooden bridge designed and built by Lewis Wernwag in 1812. After explaining the historical context of this superstructure, the book then discusses “Colossus” in relationship to its wind bracing, abutments, and structural defects. In addition, a summary of a computer analysis of the bridge is presented. Due to Wernwag’s innovated and superlative design, “Colossus” captured the imagination of both the romantic and technological minds of the day and influenced American bridge building for some time to come.