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Structural Steel Sections: 6 Types, 6 Apps, 10 Advantages

The possibilities for using steel in buildings and infrastructure are limitless. Structural steel is a popular construction material, often used alongside concrete to create impressive and long-lasting structures. With a high strength-to-weight ratio, steel can often provide a solution where other materials are unsuitable.

6 types of structural steels

Though structural steel shapes can be customized, there are actually six different types of structural steel: Angles, Beams, Bearing Piles, Channels, Hollow Structural Sections (HSS), and Plates.
Common three most common types of structural steel members are H-beam (W-shape, wide flange), I-beam(S-shape), and the U-channel(C-shape).

Types 1#: Angles

An angle is a structural shape whose cross section resembles the letter L. Two types are commonly used an equal-leg angle and an unequal-leg angle: These are steel beams with an L shape and come in many lengths and sizes. In this, two steel legs come together at a 90-degree angle, and each leg may be unequal or equal in length.
The angle is identified by the dimension and thickness of its legs, for example, the angle is 6 inches by 4 inches by 1/2 inch. The dimension of the legs should be obtained by measuring along the outside of the backs of the legs. When an angle has unequal legs, the dimension of the wider leg is given first. example just cited. The third dimension applies to the thickness of the legs, which always have equal thickness.


Angles may be used in combinations of two or four to form main members. A single angle may also be used to connect the main parts together.
This kind of structural section is typically used in floor systems due to their reduced structural depth but enhanced strength-to-weight ratios. You mainly see them in infrastructure, residential buildings, mining, and transport applications.

Types 2#: Structural Steel Beams

Structural steel beams are the basis of support. The basic design is built to handle a maximum bending load with minimum material.

Beams have a flat top and bottom, called flanges (sometimes, legs). Often these flanges taper. The vertical section of the beam is called the web. The web is built to resist blunt force, while flanges resist bending. The angle which connects the web to the flanges is called the fillet.

Beams are identified by their depth, which is the distance from the top to the bottom; flange width, which is the length of the horizontal flanges; flange thickness; and web thickness.

They come in three shapes: standard or “I” beams, wide flange or “W” beams(“H” beams), and “T” beams. These structural steel pieces are widely used in construction and civil engineering, among other industries. They have usually fabricated in lengths up to 60 ft.

“I” beams/“S” beams

“S” beams(American Standard I-beam) have tapered flanges, distinguished by their cross-section being shaped like the letter I.S-shapes are used less frequently than W-shapes since the S-shapes possess less strength and are less adaptable than W-shapes.

S Beams are designed to offer superior strength with wider flanges that have a slope on the inside surface. They are used in home and building construction, truck bed frames, hoists, lifts, and more.

H-beams/W shape

The H-beams(W shape) is a structural member whose cross section forms the letter H, they have parallel flanges that are sometimes called universal beam or wide flange beams(The name describes the shape of the cross-section and legs that are parallel), and is the most widely used structural member. It is designed so that its flanges provide strength in a horizontal plane, while the web gives strength in a vertical plane. H-beams act as the critical support trusses in construction framework, they are used as beams, columns, and truss members, and in other load-bearing applications.

“T” beams

T-beams have a T-shape, like the universal beam but without a bottom flange — the top of their cross-section is a flange, which is connected to a vertical web below. Because of their shape, they’re usually applied as a load-bearing section, but they have a disadvantage in some applications: T-beams are best for reinforcement, as they do not resist bending to bear equal weight as well as the I-beam.

Types 3#: C-Shape / U Channels

The C-shape (American Standard channel, U channel) has a cross-section somewhat similar to the letter C, they have a slight slope on the inner flange surface. It is especially useful in locations where a single flat face without outstanding flanges on one side is required. The C-shape is not very efficient for a beam or column when used alone. Rather, they provide a great amount of structural support, most useful as frames and for bracing. However, efficient built-up members may be constructed of channels assembled together with other structural shapes and connected by rivets or welds.

Types 4#: Bearing Piles

Bearing piles are similar to I-beams in that they have the same shape. The only difference is that the flange thickness and web thickness of the bearing pile are equal, whereas the W-shape has different web and flange thicknesses. However, bearing piles have uniform thicknesses across all sections. Bearing piles are used to create a deeper foundation system, which is more stable and structurally sound.

Bearing piles are H-shaped steel pieces, whose design allows them to effectively transfer loads through the pile to the tip. It’s extremely durable and efficient — it can bear more than a thousand tonnes of weight. Bearing piles work best in densely packed soil, as they offer more resistance at the tip. Common types of bearing piles include h-piles, screw piles, pipe piles, and disc piles.

Types 5#: Hollow Structural Sections (HSS)

Hollow structural sections (HSSs) are steel profiles with hollow sections and can be fabricated into square, circular, rectangular, and elliptical shapes. HSSs profiles are slightly rounded, with radiuses that are about twice the value of their wall thickness. HSSs are commonly used by engineers in welded steel frames to create structures that have the capacity for carrying loads in different directions.

Types 6#: Structural Steel Plates

This structural steel section is arguably the most versatile piece. Plates are flat and are produced in a variety of thicknesses to meet construction needs where durability and weight savings are necessary. They can be cut and further processed into different sizes and shapes, depending on the application. Structural steel is usually welded to build the framework for buildings and bridges. Structural steel welders will cut and restore metal beams, columns, and girders.
In some cases, plates are attached to other steel pieces to reinforce the structure.

plate rolling machine
Plate Bending Machine

The most common type of structural steel plate is called a base plate. These are used when the foundation is shallow, uneven, or difficult to work with. In these bases, base plates are applied to a column, which helps them to distribute load towards the soil beneath in a more efficient manner. This ensures that the bearing capacity of the underlying foundation is not exceeded. Two common base plate types are slab bases and gusseted bases.

Top 6 applications of steel in buildings

  1. Structural sections: these provide a robust and stiff frame for the building and make up 25% of the steel used in buildings.
  2. Reinforcing bars: these add tensile strength and stiffness to concrete and make up 44% of the steel used in buildings. Steel is used because it binds well to concrete, has a similar thermal expansion coefficient, and is strong and relatively cost-effective. Reinforced concrete is also used to provide deep foundations and basements and is currently the world’s primary building material.
  3. Sheet products: 31% is in sheet products such as roofing, purlins, internal walls, ceilings, cladding, and insulating panels for exterior walls.
  4. Non-structural steel: steel is also found in many non-structural applications in buildings, such as heating and cooling equipment and interior ducting.
  5. Internal fixtures and fittings: such as rails, shelving, and stairs are also made of steel.

10 advantages of structural steel

Structural Steel is a high-utility building material that is made of a versatile type of carbon steel that’s available in a range of metal grades. Uses span everything from bridges to residential and commercial constructions, from parking garages to machine bases.

  • Cost-effectiveness. Overall costs including erection, material, and fabrication are lower than other building systems and do not experience diminishing returns.
  • Accelerated schedules. Off-site fabrication supports quick construction, even in adverse weather conditions.
  • Increased usable floor space. Design flexibility makes open spaces possible.
  • Aesthetically pleasing. Pliability offers designers many options to create beautiful spaces.
  • Future adaptability. Existing steel frames can be repurposed.
  • Quality and predictability. Off-site fabrication and delivery accelerate building schedules.
  • Ease of design. Consistent strength levels simplify the design process.
  • Enhanced productivity. A fully integrated supply chain and advanced technology reduce error, lower costs, and improve safety.
  • Green. As much as 93% of structural steel produced in the United States is recycled and will continue to be recyclable.
  • Solutions abound. Structural steel can adapt to resolve project challenges, wherever they may arise.

Key Takeaway

With a high strength-to-weight ratio, steel can often provide a solution where other materials are unsuitable. Steel fabrication enables the engineers of today to use special structural pieces for any type of project. The many types of structural steel allow them to create a myriad of structures for a variety of applications.

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