John Eisenmann (1851-1924) pioneered structural steel construction in the United States in the late 1800s. It substituted metal beams and other metal supporting material for the wooden beams that had been used in the past. With structural steel, buildings could rise higher and take on new architectural shapes, while being extremely strong. Eisenmann also drafted the nation’s first comprehensive building code, which was for the city of Cleveland. Building codes are regulations that control design and construction of buildings and the kinds of materials that can be used in them. They have played a major role in making all kinds of buildings – from single-story homes to the highest skyscrapers – safer and more pleasant. Eisenmann, the first professor of civil engineering at the Case School of Applied Science, co-designed the "Arcade," which was the first commercial building in Ohio to be designated as an historic landmark in architecture.
Eisenmann was instrumental in helping to erect a famous memorial to Oliver Hazard Perry. In 1813, Perry had commanded an American fleet that defeated the British at the Battle of Lake Erie. Eisenmann thought a memorial appropriate and developed a watercolor proposal. He also selected a spot on the Lake Erie Islands for construction. While another design was ultimately selected for the monument, Eisenmann's suggested location of South Bass Island was where the Perry memorial was erected in 1912.
Eisenmann also designed the Ohio State Flag in 1902. It is unique in the United States – the only birgee, or pennant shaped state flag.