It is often asked that I-beam and H-beam are similar in shape, how to choose in practical application?
Many people who have worked in the construction industry for many years cannot explain in detail.
Here’s a detailed explanation.
H-beam and I-beam are different in shape, as shown below:
I-beam steel, as shown in the name, is a type of steel with cross section looks like the character “I”.
The inner surface of the upper and lower flanges of the I-beam has a slope, generally 1: 6, which makes the flanges thin outside and thick inside.
As a result, the cross-section characteristics of I-beams in the two main planes are greatly different, and it is difficult to exert the strength in practical applications.
Although there is thicker I-beam in the I-beam steel market, the structure of I-beam has already determined its shortage in torsion resistance.
H-section steel is a widely used section steel in today’s steel structure buildings. It has many differences compared to I-beams.
The first is the flange difference and the second is that it has no inclination inside the flange and the upper and lower surfaces are parallel.
The cross-section characteristic of H-beam steel is significantly better than that of traditional I-beam, channel steel and angle steel.
H-beam steel, which is named after the alphabet “H” because its cross-section shape is similar to this letter, is an economical section steel with more optimized section area distribution, more reasonable strength-to-weight ratio.
There is no slant between the two outside beams of H-beam steel, namely, they are straight.
This makes the welding of H-beam steel simpler than that of I-beam.
H-beam steel has better mechanical properties per unit weight, which can save a lot of material and construction time.
The cross section of I-beam steel has better direct pressure bearing and tensile-resistant. However, the section size is too narrow to resist twisting. H-beam steel is the opposite.
They both have advantages and disadvantages.
H-beam vs. I-beam (The differences and applications)
The moment of inertia of the section is quite different because the cross section size of I-beam is relatively high and narrow, no matter it’s ordinary I -beam or light-duty I beam.
Therefore, they generally can only be applied directly to the parts with bending in its web plane or to form lattice-type force-bearing parts.
It is not suitable for the axially-compressed structural parts or the bending parts perpendicular to the plane of the web, which makes it very limited in application.
H-beam steel belongs to high-efficiency economic cutting profile (others include cold-bent thin-walled section steel, profiled steel plates, etc.)
Due to the reasonable cross-section shape, they can make the steel function better and bear a higher load.
Different from the common I-beam, the flanges of H-beam steel are widened, and the inner and outer surfaces are usually parallel, which makes them strong in connecting high-strength bolts and other components.
With reasonable sizes and complete models, they are convenient for design and selection (except the I-beam steel for crane beams).
The flanges of H-beam steel are all of the equal thickness, with rolling sections. H-beams also have a combined section consisting of 3 plates welded together.
I-beams are rolled section. The inner edges of the inside flanges have a 1:10 slope because of the poor production technique.
The rolling of H-beam steel is different from that of ordinary I-beam which uses only one set of horizontal rolls.
Due to its wide flange and no slope (or very small slope), a set of the vertical roll must be added for simultaneous rolling. As a result, the rolling process and equipment are more complicated than the ordinary rolling mill.
The max height of rolled H-beam that can be produced in China is 800mm, and if the higher height is required, it has to be welded.
In China, the national standard of hot-rolled H-beam steel (GB/ t11263-1998) divides H-beam steel into three categories whose codes are hz, hk and hu respectively:
- narrow flange
- wide flange
- steel pile
The narrow flange H-beam is suitable for the beams or bending parts, while the wide flange H-beam steel and H-beam steel pile are suitable for axial compression structural parts or bending parts.
Comparing I-beam with H-beam steel under the same weight, w, ix and iy of I-beam are not as good as H-beam steel.
I-beam is small in length, high in height and can only bear the force in one direction.
H-beam steel has a deep groove, large thickness and can withstand forces in two directions.
As the demand for steel structure building grows, I-beam alone can not meet the demand because even thicken I-beams are unstable when used in load-bearing columns.
I-beam can only be used for beams while H-beam steel can be used for load-bearing columns.
H-beam steel is economical section steel with better mechanical properties in section than I-beam.
It is so named because the shape of its cross-section is the same as the English letter “H”.
The flanges of hot-rolled H-beam steel are wider than that of I-beams, have greater lateral stiffness, and are more resistant to bending.
H-beams are lighter than I-beams under the same specifications.
The flange of I-beam is thick near the web while thin in the outsider. The flange of H-beam steel is equal in cross-sections.
HW, HM, HN, H are the general names for H-beam steel. H-beam steel is welded while HW, HM, HN are hot rolled.
HW refers to H-beam steel which basically has the same height and flange width, mainly used for steel core column in reinforced concrete frame column, also known as stiff steel column. It’s mainly used for the column in the steel structure.
HM refers to H-beam steel with the ratio of the height to the width of flange is roughly 1.33~~1.75; HM is mainly used in steel structure: as steel frame column or frame beam in the frame structure bearing dynamic load, for example: equipment platforms.
HN refers to H-beam steel whose height to flange width ratio is greater than or equal to 2; HN is mainly used in beams, which is similar to the usage of I-beam steel.