Description of substructure for a steel frame building

Updated March 23, 2017

Though high carbon steel had already been available for 2,000 years, the production of steel buildings exploded in the late 19th century and early 20th century, producing visible landmarks such as New York City’s Seagram Building and Paris’ Eiffel Tower. Their emergence among international skylines can be explained by the especial rust resistance of the alloy steel and the considerable ductility of high-carbon steel. However, managing the weight of these vertically constructed works of architecture is one of their major technical concerns. The construction of a steel building’s substructure enables them to handle their considerable weight. “Substructure” refers strictly to the foundation and will not address the rest of the skeleton that undergirds the building.

Purposes of Foundation

The foundation of a steel building limits damage and provides stability by absorbing tension. Usually, any steel building whose base is large than 120 square feet will require an engineered foundation (Reference 2).

Kinds of Foundation

There are two kinds of foundations for steel buildings. The floating slab technique involves pouring the concrete directly on top of the soil, resulting in the slab “floating.” The building’s columns are then reinforced to support the vertical load. The other technique involves establishing a grade beam, footing, or pier, to secure the concrete slab. The choice of foundation will depend on safety regulations, soil conditions and types of building. Most often, the floating slab technique is required.

Attaching the Skeleton

Construction workers then pour the concrete piers above or below ground, and anchor bolts are fastened onto the piers. The precise placement of anchor bolts according to the engineering design is important, since a mistake by a fraction of an inch might make the building unstable. The steel skeleton is then attached to the anchor bolts.


The purpose of the building will affect which types of foundation and building design are necessary or preferrable. For instance, some agricultural steel buildings, which are undergirded by concrete piers, do not require a foundation at all. Alternately, commercial and industrial buildings will need a very stable foundation.


A division of the Department of Labor, the Occupational Safety and Health Administration regulates the safe construction of buildings. In 2001, the OSHA passed new safety standards for steel erection for the protection of construction workers. Local and state departments also have specific regulations for the construction of steel buildings. Many of them will require stamped engineer plans.

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About the Author

John Yargo is a sports writer, living in Orlando, Fla. His work regularly appears in the "Jackson Free Press," and he has published articles on theater, fiction and art history. He has also received a master's degree in English.