Squire Whipple

Squire Whipple was an American civil engineer, bridge designer, and inventor whose iron-truss bridges and analytical writing helped establish modern bridge engineering in the United States. He was born on September 16, 1804, in Hardwick, Massachusetts, and died on March 15, 1888, in Albany, New York. His family moved to upstate New York while he was a child, and he graduated from Union College in Schenectady in 1830.

His early work included surveying for the Baltimore and Ohio Railroad and the Erie Canal enlargement, where he saw firsthand the limits of the heavy timber bridges then in use. In 1841 he patented an iron-bowstring truss, the first all-iron truss to be widely adopted for canal and short-span railroad crossings, and many examples were built along the Erie Canal in the following decades. His 1847 patent for a trapezoidal iron truss extended the form to longer spans and became the basis for what later engineers called the Whipple truss.

His 1847 book A Work on Bridge Building was the first treatise in English to give a rigorous analytical treatment of truss stresses. Earlier American bridge designers had relied on rules of thumb and proprietary patents; he showed how the forces in each member of a truss could be calculated from statics, and his methods spread through the profession in the second half of the nineteenth century.

His later work included writings on hydraulic engineering and a textbook on bridge design that went through several editions. He continued to write and patent into his seventies, and in 1872 he was elected to the American Society of Civil Engineers, which awarded him an honorary membership in recognition of his foundational role in the field.

His name Squire is from the Old French esquier, originally a young man attending a knight, later a title for a country gentleman. By the early nineteenth century it was used as a given name in New England, and he carried it as his legal first name throughout his life.