Becker, D.N. "Early movable bridges of Chicago." Civil Engineering (New York) v 13 no 9 (Sept 1943): 421-4. Engineering Village. Compendex. UWM Lib. 10 Nov 2008. http://www.engineeringvillage2.org.
This article discusses the early history and developments of movable bridges in Chicago, beginning with the city's first bridge in the early 1830s, through its growth to 48 bridges by 1890. Building developments in bridge types – from wooden to wood and iron combinations to solely iron – and the rising costs of each, are covered in the article. One also learns briefly of how citizens complained of traffic and crossing delays due to the opening and closing of the various bridges and how Board ordinances and advancements in technology led to swifter and better-scheduled bridge operations. Mentioned are the first drawbridge, which was chopped to bits in an act of rage by Chicago citizens; the later wood and combination wood & iron bridges, which were unable to withstand the wear and tear of automobiles and the great Chicago fire of 1871; and the more modern iron structures, of which discussion is continued in a later article.
American Society of Civil Engineers, Journal of the Construction Division v 101 no 3 (Sept 1975): 545-557. Engineering Village. Compendex. UWM Lib. 10 Nov 2008. http://www.engineeringvillage2.org.
This article from 1975 takes a good look at the construction elements of the Chicago movable bridges. It covers different eras of bridge building in Chicago from the first bridge in the 1800s and the pros and cons of each, to the more modern structures of the times. Readers learn about the transition from swing bridges to rolling bascules to trunnion bascules and lift bridges, the latter of which were used in some areas for railroad traffic. The article also discusses the construction process of some of the city's bridges as they were replaced with more modern-day structures. Included are photographs of various bridges over the Chicago River and construction illustrations for a trunnion bascule bridge.