How did steel-frame construction differ from the load-bearing walls of the Auditorium Building?

The primary difference between the two construction methods lies in how the building's weight is supported.

The Auditorium Building utilized traditional load-bearing walls made of granite and limestone. In this system, the exterior walls are structural elements that must support their own weight as well as the dead load of the floors and roofs. Because these walls must transfer all loads directly to the ground, they are typically thick, especially toward the base where maximum loading accumulates.1234

In contrast, steel-frame construction utilizes a rigid skeleton of steel columns and beams to carry the building's weight. This framework is structurally independent, meaning it does not rely on the walls to resist deformation or support the building's load. Consequently, the exterior walls in a steel-frame building are nonbearing, often referred to as curtain walls. These walls serve only as a protective skin or shelter and can be made of lighter, thinner materials like glass or metal, as they are freed from the structural requirements of supporting the building.5672