January 2026 Dinner Meeting: Concrete City

Chicago’s identity as a center of iron and steel high-rise skyscraper development is richly earned. However, in the late 20th century, it was also one of the most critical hubs of concrete innovation. Six towers built between 1960 and 1990 set records for height and, simultaneously, for concrete strength. Why in Chicago? Geography, geology, building culture, and collaboration all played roles. The city’s concrete industry was homegrown, with one company in particular forging new mixes and transportation strategies, and another pioneering formwork techniques and jobsite standards that improved efficiency, finish, and schedule. By the mid-1960s, concrete was highly competitive in Chicago’s construction market. Skyscrapers such as the Brunswick, Chestnut-DeWitt Apartments, and Lake Point Tower exploited concrete’s naturally monolithic behavior to pioneer new techniques. This paper draws on archival materials, contemporary press accounts, and oral histories to reveal an underappreciated narrative in the city’s architectural and engineering history and the history of concrete skyscrapers. Chicago’s collaborative building culture has made it the world’s center of concrete engineering and innovation—a legacy that informed the design and engineering of the current world record holder for height, the Burj Khalifa, and its likely successor, the Jeddah Tower, both designed in Chicago. Learning Objectives: -Understand the importance of collaborative research to the development of high-strength concrete -Understand the role of mix design and admixtures in high-strength concrete throughout the 20th century -Understand how concrete influenced structural form in high-rise design in the late 20th century. Presenter: Thomas Leslie