How did steel frame construction change the role of walls in tall buildings?

Steel frame construction fundamentally transformed the role of walls in tall buildings by shifting the structural burden from the walls to a rigid internal skeleton of beams and columns.123

In traditional masonry construction, walls were load-bearing, meaning they were required to support the weight of the floors, roofs, and the building itself. Because these walls had to resist significant vertical and lateral forces, their thickness often increased toward the base, and the number and size of windows were strictly limited to maintain structural integrity.3

With the advent of steel framing, the building's weight is carried by the frame rather than the walls. This innovation allowed walls to transition into non-load-bearing curtain walls. These "skins" serve only to provide shelter, weatherproofing, and resistance to wind forces. Freed from structural requirements, architects gained the flexibility to use lightweight materials like glass, metal, and stone wafers, enabling the creation of expansive, transparent facades that were previously impossible in tall, masonry-supported structures.1345