Turner Solterman
Structural Engineer Assistant
Skidmore, Owings & Merrill LLP, Chicago

Prior to the late 1960s, the intentional combination of concrete and steel in the structural systems of tall buildings proved difficult due to an underdeveloped understanding of global structural performance, high-strength concrete technology, installation techniques, and their relative displacement behavior. During the early 1970s, advances in these building technologies allowed materials to surpass their previously known limits, while the introduction of the computer into the design process made more sophisticated global structural studies possible. Combined with a changing economic environment, incremental advances in the material, construction, and engineering fields led to the viability of new composite building systems. The speed of construction, cost effectiveness, and material savings of these new systems led to their adoption into the industry as a popular structural solution.

Initially implemented in high-rise office construction, the combination of concrete and steel framing to deal with lateral and gravity loads drove the modern era of skyscraper technology. The historical significance of the first composite building system, One Shell Square in New Orleans, represents the culmination of a fundamental paradigm shift from single-material structures.

The evolution of composite systems resulted in many interpretations of structural form, most common being a concrete core wall system surrounded by steel floor framing (e.g., Jin Mao Tower, Jinling Hotel Tower). As additional environmental and resilience related considerations increase, integration of mass timber and the utilization of topology optimization across multiple materials to further reduce consumption are just two examples of how composite building philosophies may continue to emerge and evolve to address these new design challenges.