Types of Structural Systems Explained

Every building, from a single-family home to a multi-story commercial property, relies on a structural system to carry its weight and resist outside forces. While finishes and layouts get most of the attention, the structural system determines what spans are possible, where walls can go, and how the building performs during storms.

Understanding the main types of structural systems can help property owners, architects, and contractors make better decisions early in a project. Here’s a straightforward look at the most common structural systems and how they work.

In This Article

• What a Structural System Does
• Load-Bearing Wall Systems
• Frame Systems: Steel and Reinforced Concrete
• Lateral Systems: Shear Walls, Braced Frames, and Diaphragms
• Foundation Systems and Choosing the Right Structure

A structural system has two main jobs. First, it carries gravity loads, such as the weight of the building itself, people, furniture, and equipment, down to the foundation. Second, it resists lateral loads, such as wind and, in some regions, earthquakes, that push sideways on a building.

In South Florida, wind is usually the controlling lateral force, so structural systems must be designed to keep the building stable and connected from the roof all the way down to the foundation. The best system for a project depends on the building’s size, use, budget, and design goals.

Most buildings combine several systems. A typical South Florida home, for example, might use reinforced concrete block walls, a wood-framed roof, and a slab-on-grade foundation, all tied together with engineered connections such as straps, anchors, and tie beams.

In a load-bearing wall system, the walls themselves support the floors and roof above. This is one of the most common systems for homes and low-rise buildings.

• Concrete block (CMU) walls: very common in Florida, typically reinforced with steel and grout-filled cells
• Wood-framed walls: used in many residential projects, often combined with structural sheathing
• Cast-in-place concrete walls: used where greater strength or durability is required

Because these walls carry loads, removing or altering them requires engineering. Learn more in our article on whether you can remove a wall in your house.

Frame systems use columns and beams to carry loads, allowing walls to be non-structural. This creates more flexibility for open floor plans, large windows, and future layout changes.

• Reinforced concrete frames: widely used in Florida for mid- and high-rise buildings because of their durability and resistance to moisture and wind
• Structural steel frames: allow long spans and faster erection, common in commercial, retail, and industrial buildings
• Light-gauge steel and wood frames: used for smaller structures and additions

Choosing between concrete and steel often comes down to the building’s height, span requirements, construction schedule, and exposure to coastal conditions. Concrete performs well against moisture and corrosion near the coast, while steel can reduce the number of columns needed and speed up construction. Many buildings use a combination of both, such as concrete foundations and columns with steel roof framing.

Lateral systems keep a building from racking or overturning under wind loads. The most common types include:

• Shear walls: walls specifically designed and connected to resist sideways forces
• Braced frames: steel frames with diagonal members that stiffen the structure
• Moment frames: rigid beam-to-column connections that resist lateral forces without diagonal braces
• Diaphragms: floors and roofs that act as horizontal beams, transferring wind forces to the walls or frames below

Continuous load paths and properly designed connections are critical. A building is only as strong as the connections that tie its components together.

The foundation transfers all of the building’s loads into the ground. Shallow foundations, such as spread footings and slabs, work well where soils are strong near the surface. Deep foundations, such as piles or helical piers, are used where soils are weak, loads are heavy, or the site is subject to flooding or erosion.

Choosing the right structural system involves balancing cost, design intent, site conditions, and code requirements. At Axiom Structures, we help clients throughout South Florida evaluate structural options and design systems that are safe, efficient, and buildable. Learn how strategic choices can control costs in our article on value engineering.