Bending Beam: Steel Structure Bending Basics

In this article, we describe the basic knowledge and bending methods of six types of steel beams in steel structural profiles.

The bending/rolling steel beam is the process of curving a steel beam to a specified radius and arc length(Single radius, multiple radii, or S-shaped reverse bending, etc.). A bending beam is commonly used to describe a tighter radius bend process, whereas a rolling beam is used to describe a larger radius bend.

Basic Knowledge of Steel Beams

Steel structure is a structure that can be seen everywhere in modern life. Stability, durability and plasticity, as its three characteristics, allow it to play a very important role in daily life and manufacturing.

• Nowadays, due to its superior performance and distinctive aesthetic style, steel structures have become the first choice of many architects when designing and repairing monumental buildings. Whether it is the realization of the shape or the atmosphere, the steel structure plays an irreplaceable key role.
• Another major aspect of the application of steel structures in modern life is its application in mechanical design. Nowadays, many places require large-scale machinery with relatively high precision and fast operation speed, allowing these instruments to return to their original origins. When the time comes, we will find that these instruments are made up of steel structures spliced one after another.
• In addition to its use in mechanical manufacturing and architectural design, steel structures are also very active in the industrial market in the 21st century.

The commonly used steel structures in steel structures are steel beams:

What is?

A strong and durable material with a high strength-to-weight ratio and the ability to withstand loads, steel is one of the most commonly used metals for a variety of construction and similar project needs, and some specific steel varieties tend to be most useful here. Particularly common in various building frames and support structures, they are called steel beams.

• Steel beams are metal rods with a unique shaped profile, most commonly found in structural engineering applications. They are made of steel.
• The size and length of any given steel beam will depend on the specific needs of the project, but all steel beams have cross-sections that provide additional support.
• Steel beams have become one of the most popular structural support options for projects due to their durability and strength, as well as their affordability compared to other materials.
• Steel beams are used in industrial buildings and metal structures: such as factories, bridges, ships, agricultural machinery and vehicle manufacturing, transmission towers, and transportation machinery, often in combination.

Types of Steel Beams

Different structural steel beams commonly used in the construction, manufacturing and transportation industries come in a variety of sizes and shapes, including W-shaped beams (wide flange beams), I-beams, H-beams, L-shaped beams (Angle Beam), Parallel Flange Channel (PFC) Beam/C Channel/C Beam, U Beam/C Channel, T Beam/T-section/Tee Beam. Except for the H beam and steel pipes, which are hot-rolled and welded, the other steel beams are all hot-rolled.

Types 1#: W-beams

Also called a wide-flange beam, has wide top and bottom flanges (the flanges are not tapered), the flange is thicker than the web, is equal in thickness from tip to web and is at right angles to the web Structural steel profiles that provide extra strength and stiffness. They are used in the construction of bridges and highways. Due to their shape and size, they can support heavy loads and provide structural support and stability.

Types 2#: I-beams

An I-beam is a structural section with tapered flanges (narrow top and bottom flanges) that are generally not as long as the flanges on a wide-flange beam. The flange has a thicker cross-section, a thinner flange toe, top and bottom flanges to prevent bending, and a web to resist blunt forces. This allows them to carry loads in one direction more efficiently (to handle maximum bending loads with the minimum amount of material).

Types 3#: H-beams

H-beams look a lot like I-beams, but are heavier, have wider flanges, and a thicker center web: the top and bottom flanges are the same width, and the H-beam’s wider flanges provide more surface area, This is particularly advantageous in terms of load distribution, which makes them ideal for a variety of applications. This is why H-sections are commonly used in bridges, machinery, and heavy truck frames. H-beams have greater load-carrying capacity than I-beams.

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Types 4#: T-beams

T-beam is an I-beam or wide flange that is divided into two parts along the middle of the web, typically used in load-bearing applications; the highest point of the T-beam is a flange or compression member that resists compressive stress; the flange forms The top of the “T” shape, while the stem provides vertical support, this structure allows the T-shaped beam to effectively distribute heavy loads. The most common uses include framing, repairs, roof trusses and shipbuilding.

Types 5#: C-beams

C-beams/Channels are C-shaped structural members consisting of a flat back (web) and two vertical extensions (flanges) on either side, with tapered flanges that are thicker starting from the web and increasing as the overall width is reached The ends gradually become thinner. Depending on the application, the flange can face outward (open side) or inward (closed side). Used in construction to provide structural support and resist loads. They are strong and durable, making them ideal for use in construction due to their high strength-to-weight ratio.

Types 6#: L-beams

Angle beams, also known as L-beams: L-shaped structural members, easier to connect because the 90° angle provides more freedom; unique shape provides excellent weight-to-strength ratio, used in construction Provide structural support and resist loads. L-shaped or angular beams fill the special need of structural corners that many buildings require for stability and proper weight distribution, and are often used in conjunction with other structural components such as beams and columns to create a strong and stable structure.

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Bending Methods

The seven most widely used bending methods in the industry are listed in more detail in the American Institute of Steel Construction (AISC)  design guide 33 section 2.2.

Bending is a process of processing straight steel beams into a certain arc through specific equipment or tools. In the bending industry, circular shapes are the most common and simplest, while workpieces with three-dimensional curvature are the most difficult and rarely used.

Profiles can be bent into shapes: If distinguished by specific shapes, there are too many. Generally, they can be distinguished by the type of shape: divided by spatial dimensions, they can be divided into two-dimensional workpieces and three-dimensional workpieces. If divided by curvature, they can be divided into single curvature (radius) ) workpieces and multi-segment arc (variable curvature) workpieces, the actual workpiece is often a composite of these two. For example, a circle can be regarded as a two-dimensional workpiece with a single radius. As another example, the quincunx shape can be regarded as a two-dimensional multi-segment arc workpiece with variable curvature.

What Shapes Can Steel Beams Be Bent Into?

Due to the cold work hardening of metal steel beams, the mechanical properties of the material can be improved after bending. There are various geometries available for curved members and the methods used to bend them. Due to the wide variety of bending equipment available, almost any structural shape can be curved.

Steel beams can bend a variety of curve shapes, standard bends(two-dimensional workpieces) are the simplest type, where a steel beam is bent about a principal or geometric axis to form a single-radius curve: bending conventional standard arcs. It can also bend multiple arcs, as well as parabolic, elliptical, and other non-circular bends: U shapes, S shapes, W shapes, ellipses, parabolas, arcs with straight segments, conical curves, and multiple curves on one curve, a series of complex curve shapes such as various radii.

Standard Bending

A “standard bend” is a common steel beam bending that bends the beam into a single radius curve along a specific axis to meet specific design requirements or functional needs. It has the following three characteristics:

• Single Radius Curve: Standard bending usually deforms the steel beam along a specific radius curve, which is usually an arc rather than a complex polygon.
• Based on the principal or geometric axes: When performing standard bends of steel beams, it is common to operate around the principal or geometric axes of the steel beam to ensure that the resulting bend meets the design requirements and is able to withstand the expected stresses and loads. In this case, the member can be bent about the weak axis, known as bending the easy way, or bent about the strong axis, known as bending the hard way. Hard-way and easy-way bending are sometimes called camber and sweep, respectively.
• Application: Standard bending is often used to manufacture structural parts, such as beams, columns, etc. in steel, and elbows, elbows, etc. in pipes.

Off-axis Bending

Off-axis bending, also known as conical rolling, involves bending steel beams along a non-principal axis or non-geometric axis, as opposed to standard bending.

Typically, this curvature is produced by constant rotation relative to the plane of curvature, although variable twist along the member axis is also possible. Special tooling is often required to limit deformation and ensure dimensional accuracy.

Off-axis bending is usually used where the member is required to bend and tilt simultaneously so that the member axis is parallel to the bending surface. In commercial structures, this often occurs in the horizontal members of canopies, vaulted roofs, and domes. These members are also commonly used as circumferential stiffeners in industrial tapered plate structures such as hoppers and chimneys.

In addition, off-axis bending is also used to manufacture roofs, domes, etc., and can provide various shapes from angles, bars, beams, channels, and pipes to metal sheets. Funnels, transition pieces, and chimneys in industry are also common applications for off-axis bending.

Bending Process

Bending or rolling steel is the process of curving a length of steel, also known as a steel member, to a specified radius and arc length. The radius of a bend is the most critical piece of information required to curve steel beams. The radius requirement dictates the bending process used. Rolling is used to describe a larger radius bend while bending(Such as Rotary Draw and Hot Bending) is commonly used to describe the process for a tighter radius bend. Different beam bending methods will result in different cost structures. The various bending methods are dictated by the material size, material thickness, bend radius, and structural steel beam (AESS) level. An excellent profile bending machine for the beam rolling process can offer the best process for your specific project.

Based on the information on AISC, the most commonly used processes in industry at present appear to be pyramid rolling, gag pressing, rotary‐draw bending and induction bending. In fact, in China, it is now common to use industrial stretch bending machines to bend large structural steel beams, but the proportion is smaller than that of roll bending.

Cold Bending

Rolling Beam

When bending steel beams using roll bending, one end of the steel beam is first fed between the upper and lower rollers of the three-roll profile bending machine. Then, the left and right rollers move upwards, causing the steel beam between them to undergo a certain plastic bending deformation due to compression. When the upper roller makes a rotary motion, the meshing moment formed by the friction between the steel beam and the roller causes the steel beam to feed; when the steel beam passes between the upper and lower rollers (i.e., the deformation zone) in sequence, the steel beam obtains plastic bending deformation along its entire length. This is a process once mentioned in a magazine of AISC.

For more on excellent profile bending machines, see Advantages of PBH Section Bending Machine.

Gag Pressing Beam

Gag pressing, also known as point bending or cold cambering, gag pressing is a bending method that uses hydraulic rams to simultaneously apply forces at discrete locations along the member to produce large-radii bends. Place the steel beam horizontally on the side of the cambering mold, use a powerful hydraulic cylinder to apply pressure from the discrete locations, and the steel beam forms the required cambering. This is the most common method for cambering beams to offset a portion of the service-load deflections; therefore, the hydraulic rams are located approximately at one-third points to produce a curved shape approximating a typical beam deflection curve.

Stretch Bending Beam

The stretch forming machine clamps the steel beam with the stretching arm and stretching cylinder jaws to apply prestress to the profile, reaching the yield strength of the steel beam. Then, the bending machine’s rotary cylinder loads the bending rotation, and the stretching cylinder applies axial tension according to the programmed axis tension, causing the steel beam to move around the bending die in a snug fit motion, shaping the steel beam. During the stretch forming process, while the workpiece is being bent, the stretching cylinder always applies axial tension to the steel beam, and the elongated portion of the beam length is constantly compensated by the stretching cylinder traction, thereby avoiding the tendency of steel beam wrinkling and achieving a good bending arc effect.

Hot Bending

The metal beam can also be bent incrementally hot or incrementally cold. This is where small sections of material are bent at one time. When finished the section has a smooth curve to the bent section.

Application of Bending/Rolling Beams

• Bending/rolling beams are widely used in construction projects, including buildings, bridges, and other structures. They are often used in conjunction with other structural components such as columns, beams, and supports to create a strong and stable structure. Structural steel beams can be machined into a variety of shapes and sizes to meet specific design requirements, and they can be coated or treated to improve their appearance or protect them from corrosion.
• In manufacturing, bending/rolling beams are used to make conveyor systems, scaffolding, and industrial equipment. The automotive industry uses I-beams to create tram tracks, elevators, trailers, and even truck bed frames and support structures.
• Other Applications: In addition to structural uses, bending/rolling beams are also used in artistic and decorative applications and can be used as decorative features on building facades or as sculptures in public spaces.