Steel Beams: Advantages, Types, and Applications

Steel beams are fundamental structural elements for the construction of buildings, bridges, industrial warehouses, and many other civil engineering works. Thanks to their high mechanical performance, lightness, and versatility, they represent a perfect solution in numerous design contexts, especially where strength, rapid assembly, and sustainability are required.

In this article, we delve into what steel beams are, the main types, and how to choose the most suitable one based on the type of structure. We will also see what advantages they offer compared to other materials, and how they can be designed and drawn with the help of a BIM structural calculation software.

Steel beam

What are steel beams and why are they used?

Steel beams are linear structural elements designed to primarily resist bending and shear stresses. They are used to support loads and transfer them to columns, walls, or foundations, playing an essential role in the stability and distribution of forces within a building or structure.

The use of steel in construction is motivated by numerous advantages: it has a high mechanical strength, an excellent strength-to-weight ratio, and a predictable behavior under load. Moreover, due to its ductility, it can deform without breaking, ensuring safe behavior even in the event of exceptional occurrences such as earthquakes or unexpected overloads.

Steel beams easily adapt to various design needs, both in civil and industrial contexts, and are particularly appreciated for their rapid assembly, the ability to create large spans without intermediate supports, and the ease of integration with other materials, such as concrete or wood, in mixed structures.

Characteristics of steel beams

Steel is a versatile material, characterized by high strength, ductility, and durability. The strength of steel beams is a fundamental characteristic that ensures their ability to withstand high loads. Steel is indeed a highly resistant material, with a tensile strength of about 300 MPa. This strength is guaranteed by regulations, which impose minimum values for the tensile strength of the steel used for beams.

Steel can be processed with various methods, such as:

• rolling – is a hot forming process of steel, which allows obtaining different profiles, such as I-beams or T-beams;
• water jet cutting – is a steel cutting process that uses a high-pressure water jet, allowing precise shapes and dimensions to be obtained;
• punching – is a steel drilling process that allows for the creation of holes and openings of different sizes.

The processing of steel influences the strength of the joints, i.e., the points of connection between the beams and other structural elements. The joints must be designed and made in a way that ensures the strength and durability of the structure. The processing of steel must therefore take into account the expected stresses and the characteristics of the material to guarantee the strength and durability of the joints.

Another characteristic of this structural element arises from its use in seismic construction. In fact, steel beams are often preferred over reinforced concrete beams due to their greater strength and deformability. Steel beams can be designed to withstand seismic stresses, ensuring the safety of structures in case of earthquakes.

Types of steel beams

There are different types of steel beams, each with specific characteristics.

Among these, we can mention lattice girders, T-beams, I-beams, and box girders.

Lattice girders

Lattice girders are composed of a series of vertical and horizontal members arranged to form a grid. This arrangement gives the beam great resistance to bending and torsion. They are often used in large structures such as bridges and tall buildings.

Lattice girders are made up of various components, including the top chord (upper horizontal rods), the bottom chord (lower horizontal rods), vertical members (vertical rods), and diagonals (inclined rods). These components, arranged in a triangular grid, work together to ensure the strength and stability of the structure.

Here is a detailed overview of the main characteristics of lattice girders in steel:

1. structural efficiency: lattice girders are designed to evenly distribute loads along their length, using the triangular geometry to maximize the strength and rigidity of the structure. This triangular arrangement minimizes the weight of the beams while ensuring high load-bearing capacity;
2. lightweight: thanks to their efficient geometry and the ability to use high-strength steel, steel lattice girders can be designed to be lightweight without compromising their structural strength. This allows for greater flexibility in design and reduces the overall static load on the building;
3. rigidity: the triangular arrangement of lattice girders provides significant stiffness to the structure, helping to limit unwanted movements of the building under load. This rigidity is particularly important in buildings subject to vibrations or seismic movements;
4. ease of assembly: steel lattice girders are often prefabricated in the factory according to project specifications and then transported to the construction site for assembly. This prefabricated construction method can speed up the construction process and reduce overall project costs;
5. architectural design adaptability: lattice girders offer flexibility in architectural design, allowing for wide spans without the need for intermediate supports. This enables the creation of open and flexible interior spaces, ideal for various types of buildings such as large warehouses, shopping centers, and public areas.

Lattice girder

T-Beams

The steel T-beams consist of a T-shaped section, with an upper flange connected to a central web (also called stem or flange). This arrangement gives the beam great resistance to bending, but less resistance to torsion compared to lattice beams.

These beams are part of the family of merchant sections and can be produced with equal or unequal cross-sections, thus offering great versatility in application and becoming popular in various industrial sectors.

During the hot rolling process for the production of T-beams, primary steel products are heated to about 1100 degrees Celsius to allow drastic deformation of the steel using a few rolling cycles. This process mainly deals with manipulating the shape and geometry of the material, creating a smooth and attractive finish on the product’s surface.

Steel T-beams can be produced in different sizes and thicknesses, offering a wide range of options for structural applications. These beams are used in sectors such as construction, engineering, railway, naval, agricultural, fencing, safety applications, and many other sectors where strength, ease of processing, and versatility are essential.

The advantages of mild steel T-beams include universal availability, rapid production in large quantities, and relatively low costs. The low carbon content and yield point of steel T-profiles allow for easy handling, fabrication, and processing without the use of special machinery. The simple handling and connection to other materials increase the versatility of T-beams, making them suitable for a wide range of structural applications.

IPE Beams

The IPE beams, acronym for “European Profile” (where the I recalls the shape of the beam), are structural elements in the form of bars or beams with parallel flange inner surfaces and defined dimensions. Below we will see in detail the characteristics of these beams:

• section shape: IPE beams have a cross-sectional shape of “I”, with two flanges, one upper and one lower, connected by a central part called the web. This particular shape provides the beams with a remarkable bending resistance capacity, making them suitable for withstanding static and dynamic loads;
• structural efficiency: the “I” shape of IPE beams makes them particularly efficient from a structural point of view, allowing them to bear loads and transmit forces within a building optimally. This efficiency enables the construction of stable and safe structures with a minimal amount of material;
• use in floor constructions: thanks to their ability to withstand bending loads, IPE beams are commonly used in floor construction, where they must support the weight of the superimposed structures and distribute loads evenly on the supporting pillars or walls;
• various sizes and weights: IPE beams are available in different sizes and weights, ranging from lighter versions, such as IPE AAAA to A, to heavier versions, such as IPE O. This variety allows for choosing the most suitable beam for the specific project requirements.

IPE Profile Beams

Box girders

The box girders are made up of a box-shaped section, therefore with a closed cross-section with four lateral flanges and a central web, which makes them more resistant and rigid compared to other forms of beams. This arrangement gives the beam great resistance to bending, torsion, and compression.

Box girders are often used in large structures, especially in the infrastructure sector.

Now let’s see what are the most important aspects, characteristics, and applications of box girders:

• cost and complexity: box girders can be more expensive and complex to manufacture compared to twin girder beams, as they are heavier and require a more complex construction. However, they become competitive if made entirely in the workshop and have a narrow width, usually less than 5 meters;
• torsional stiffness: box girders are particularly suitable when high torsional stiffness is required. This characteristic makes them ideal for applications such as curved decks or situations where it is necessary to reduce the deck height;
• trapezoidal box: compared to a rectangular box, a trapezoidal box has the advantage of containing the width of the bottom and reducing the ineffective part due to shear lag. This can be advantageous to improve structural performance and reduce costs;
• alternative solutions: in some situations, such as very wide or curved decks, alternative solutions to box girders can be used. These include the use of inclined truss beams or simple struts connected to the bottom of the box, which can help improve torsional stiffness and optimize structural performance;
• stiffeners and diaphragms: to ensure the stability and strength of the box section, it is often necessary to use stiffeners such as diaphragms or truss structures. These elements are placed inside the box to absorb torsional effects and ensure the stability of the structure.

Steel beam

Steel Joists and Beams

Steel joists and beams are small to medium-sized structural elements, primarily used for the construction of floors, ceilings, and secondary structures. Despite their smaller dimensions compared to main beams, they play a fundamental role in load transfer and stress distribution within the building.

These profiles can be used individually or in combination with other materials (such as brick or concrete), giving rise to mixed systems that are very common in construction.

Depending on structural needs and the type of application, it is possible to choose from various solutions:

• steel joists: often used as load-bearing elements within composite steel-concrete or steel-brick floors. They can be made with rolled profiles (such as IPE) or fabricated through welding or bolting;
• beams: a generic term used on-site to refer to small and medium-sized beams (often light IPE), used for secondary supports, infill frames, substructures, or even temporary elements.

The use of these elements offers numerous advantages, both in the design and installation phases:

• lightness and ease of assembly: the reduced weight allows for rapid assembly, even in contexts where the use of lifting equipment is limited;
• versatility: they can be easily cut, drilled, and welded on-site or in the workshop, adapting to multiple geometric and structural configurations;
• compatibility with other materials: they integrate well into mixed floors, reducing the overall weight of the structure compared to fully concrete solutions.

Thanks to their cost-effectiveness and ease of use, steel joists and beams represent a practical and effective solution for reinforcing existing floors, creating mezzanines, and more generally for all lightweight structures where quick installation and good load-bearing capacity are required.

Advantages of steel beam

Now let’s take a detailed look at the advantages of steel structures:

• strength and design freedom: steel offers architects the opportunity to express their creativity thanks to its combination of strength, durability, precision, and ductility. This allows for exploring innovative ideas and developing new structural solutions, including designs, shapes, colors, and textures. The ability of steel to bend allows for the creation of free forms, segmented curves, facades, arches, or domes, allowing for distinction in architectural design;
• fast and efficient assembly: steel structures allow for quick and efficient assembly in all working conditions. Prefabricated components off-site can be assembled with minimal on-site labor costs, reducing assembly times by up to 40% compared to traditional methods. The lightweight of steel allows for reduced and simpler foundations, leading to economic advantages and an early return on investments;
• adaptability: steel structures can easily adapt to future changes in building functions with reduced costs. They are ideal for remodeling and revising the building based on customer specifications, allowing for changes in internal or external layouts;
• open space: steel sections offer an elegant method to cover long distances, allowing for the creation of large open spaces without intermediate columns or load-bearing walls. The reduction in the number of columns facilitates space customization and unleashes creativity;
• recyclability: buildings made with steel structures can be reused after demolition, as steel can be recycled indefinitely without losing its properties. This reduces waste and contributes to environmental sustainability;
• fire and earthquake resistance: steel structures are fire-resistant and can effectively protect people and properties. In case of earthquakes, the flexibility of steel allows the structure to bend under extreme loads without collapsing, ensuring the safety of occupants;
• environmental respect: steel structures are lighter and less bulky than concrete ones, reducing transportation and fuel consumption. The 100% recyclability of steel allows for reuse without leaving waste, while low energy consumption contributes to environmental sustainability.

How to design steel beam

Let’s see how to make use of a software for structural calculation to design and create steel beams of different shapes.

FAQ – Steel Beams

What are the advantages of steel beams?

Steel beams offer high mechanical strength, lightness, rapid assembly, and great design versatility. Additionally, they are 100% recyclable and provide excellent performance even in the event of earthquakes.

In which fields are steel beams used?

They are used in civil and industrial buildings, bridges, warehouses, floors, mezzanines, and large-span structures. They adapt to multiple needs, even in combination with concrete or wood.

Can steel beams be used in outdoor environments?

Yes, but they need to be protected against corrosion. Anti-corrosive coatings (such as hot-dip galvanizing or epoxy painting) are used, or stainless steel or corten steel is employed for direct exposure to weather conditions.

What are the main types of steel beams?

The most common are:

• truss beams, ideal for large spans and lightweight but strong structures;
• T-beams (or beams), used in metal frames and reinforcements;
• IPE beams (double T), versatile for floors and buildings;
• box beams, perfect for bridges and decks;
• joists and beams, for floors and secondary structures.

Why choose steel beams instead of concrete ones?

Compared to reinforced concrete, steel beams are lighter, stronger, and more deformable. This makes them safer in the event of seismic stresses and quicker to assemble on-site.

Can a steel beam replace a reinforced concrete beam?

In many cases, yes, especially when greater lightness, rapid installation, and high strength are required. However, steel and reinforced concrete have different structural behaviors, so a direct replacement is not always possible. A careful technical assessment is necessary to verify compatibility, static performance, and connection methods with other structural elements.

Do steel beams deform over time?

If designed and installed correctly, no. Steel has excellent dimensional stability and is not subject to significant permanent deformations over time. However, it is important to check for potential risks of lateral instability or flexural-torsional instability.

Are steel beams sustainable?

Yes. Steel is fully recyclable without loss of quality, allows for lightweight and fast constructions, and can be reused after demolition. Additionally, prefabrication reduces waste on-site.

How are steel beams designed and drawn?

Design requires sizing and verification of stresses. With a BIM structural calculation software, it is possible to model them in 3D, analyze loads, verify nodes and connections, and produce technical documents such as executive drawings and calculation reports.