3-Structural steel sections-an easy approach.

Last Updated on February 21, 2026 by Maged kamel

Structural steel sections.

Structural steel sections.

We shall examine the various steel forms as an introduction to the structural steel sections. The displayed slide illustrates the multiple shapes present, including W-, M-, S-, Hp-, C-, L-, Wt-, St-, and hollow portions, with the symbol HSS.

We have double angles and also pipe shapes.

The wide flange, or I-beam shape, represented by the symbol W.M., is an acronym for Miscellaneous Beam.

Additionally, the miscellaneous beam has a thin Web and is an I-beam. The S-shape’s internal slope in the flange is quite noticeable.

For bearing piles, the HP forms are employed. The Standard C channel is represented by the letter C. To create a W.T. section, we cut from an original W section to create a W.T. section. Originally from the W section, Wt stands for the T section.

A Tee section cut from an S section is indicated by the symbol St. Which table item is T cut from W? Tees taken from the Miscellaneous area is what the MT stands for. Additionally, S-shaped shirts are St portions. HSS is an acronym for hollow structural sections that are rectangular in shape, as well as for pipes and round forms.

The next slide shows the different shapes and their related symbols.

The ASTM designation for the different structural steel sections.

The following table contains the shape and ASTM designation. The wide-flange beams are ASTM-A-992, with Fy ranging from 50-55 ksi, and the Rupture stress is 65 ksi. For Miscellaneous beams and their ASTM designation, ASTM-A-36, Fy is 36 ksi, and the Rupture stress is from 58-80 ksi.

W-section is one type of Structural steel section.

We have examined one part of the W section in the following slide. Section W 44×335 is examined. The weight per unit length is represented by the number 335.

Inch^2 is used to express the area. W44x335 has an area of = 98.50 inch^2. The depth of the entire section, including the web and flange, is measured from top to bottom and is denoted by the letter d.

We refer to the web’s thickness as tw, and its value is 1.03. It can be found in the table. The table also includes tw/2 as part of the sketch.

The thickness is shown in the following column to the closest 7/16″. The flange has a width of 15.9″ and a thickness of 1.77″ (bf=1.77″). The vertical distance from the top to the bottom of the round portion’s end is known as the k value.

The horizontal distance from the y-axis to the round’s finish is denoted by K1. T is the vertical distance along the web that is measured between the top and bottom ends of the rounded part.

As a practical gauge, the architectural dimension is also represented by a column. The wide-flange, or W-shape, is the most widely used structural shape, to quote.

It is symmetrical twice around the x and y axes. For most groups, the flange faces are almost parallel to the inner flange distance.

How to derive the corresponding SI units for a section?

We can refer to part 17 in the AISC Manual for the SI Equivalents of Standard U.S.
Shape Profiles.

The following slide includes Table 17-1, the Si equivalent of standard U.s shape Profiles.

One pound-force is the force that acts on a 1 lb mass with an acceleration of 32.20 ft/sec2. The corresponding acceleration in SI units is 9.8066 m/sec2. One Pound mass=0.4536 KG mass.

So we could write that one pound-force is the force that acts on a 1 Lb mass with an acceleration of 9.8066 m/sec2. Substituting for 1one pound mass as 0.4536 kg.

So we could write that one pound-force is the force that acts on a 0.4536 kg mass with an acceleration of 9.8066 m/sec2. We can get that one pound-force = (0.4536* 9.80665) = 0.45359 kg-force.

One ft =30.48 cm=304.8*(1/100)m=0.3048 m. Thus, we can derive the conversion factor between LbF/FT to Kg/m.

For a W44x335 W structural steel section. The overall height is 44 inches, since 1 inch = 25.4mm. The first figure will be 44 × 25.40 = 1117 mm, taken as 1100 inches.

For 44 lb/ft=335(1.488)=498.48 kg/m=499 kg/m, which is the weight per unit length.

But with 499 km/m. The overall depth is approximately 1100mm.

The difference between W and S shapes.

The following slide shows the differences between W and S shapes, two types of structural steel sections. The section’s flange width is smaller. The inner face of the Flange has a slope of approximately 16.7 degrees. The theoretical depth is the same as the nominal depth.

For instance, an S510x111.6 has a nominal depth of 510mm and a weight of 111.60 kg/m.

To get the dimension in lb-Ft for the depth=510/25.40=20.07 ft, taken as 20′. While for the weight =111.60/(0.4536/0.3048)=75.00 lb/ft.

M-section is one type of Structural steel section.

In the next slide, M shapes are doubly symmetrical shapes, and M shapes are not classified as W, or S.M stands for miscellaneous.

There are 16 lightweight shapes classified as M. An M318x18.5 is the largest M shape, with a nominal section depth of 318mm and a mass of 18.5 kg/m. The overall depth is 12.5 inches, and the weight is 12.40 pounds per linear foot.

C shapes and HP structural steel sections review.

In the next slide, we will check the C-shapes. We have a flange and a web. The C-channel table includes the flange width, bf, and the average thickness, tf.

In the table, there is a web height and thickness. The web height is measured from the Overall depth of the C-channel, which is d minus 2k.

The first column in the C-Channel table is the Area. For a C channel, C15x50. The overall height d is 15.0 inches, and the weight is 50 pounds per foot. K value is the distance from the end of the slope to the upper Flange.

The T is the distance between the upper end of the slope and the lower end of the slope. Table 1-4 is from the AISC tables.
H-P shapes are used as bearing piles. H.P. section of 18×204. The overall depth of that section is approximately equal to 18 inches; the actual depth is 18.30 inches. There is a slope and a round portion. Table 1-4 gives complete information on the Flange and web data.

MC-angles, structural steel sections review.

In the next slide, we have MC-Shapes—the Miscellaneous C-shapes. This is the second part of the table that includes the nominal weight. Every table has two parts: the first contains data for the Area, Flange, and web. The second part consists of the elastic and plastic section modulus and the inertias and radii of gyration.

We will talk about the elastic and plastic section moduli of the beam section, by God’s will.

r stands for the radius of gyration, which is equal to sqrt of I/A. S stands for the elastic section modulus.

Z is the plastic section modulus. Torsional properties are given; Ix is bigger than the inertia about the y-axis. There  is Sx and Sy in inch3, rx=sqrtof(ix/A), while ry=sqrt(Iy/A), x bar. Zx is the section modulus, and J is the polar moment of inertia.

The items CW & H are for estimating torsional data. The following table is for angles. For a section, L8x8  represents an equal angle of 8 inches. The K value is given. The values of weight and Area are given.

WT-shapes and Si equivalence.

In the next slide, we have data on the W.T. shape; these T-sections are cut from a W-section. The table includes the different sizes of the WT shapes.
We have the web, which is called the stem. We have bf for the flange width, and tf is the flange thickness. The stem is the vertical portion of the WT shape.

The area and depth are included in Table 1-8. These are corresponding sizes in SI units. WT205x29.8 is a structural tee with a nominal depth of 205 mm and a mass of 29.8 kg/m. Wt shape is due to the cutting of a W-section of w410x59.6. The W-section is a double-depth of the required W.T. section.

The x-axis data includes the values of inertia, elastic section modulus& radius of gyration, y-bar, and plastic section modulus.

The W section will have double the required W.T. section weight. W16x40 will produce two Wt sections of 8×20.

The next slide shows the difference between WT and MT shapes.

The following slide shows part 17 of the construction manual and the tables that belong to it.

On the next slide, a summary of the various items is given. A W27x114 is a W section that is approximately 27 inches deep and weighs 114 pounds per foot. An S12x35 is an S section 12 inches deep, weighing 35 pounds per foot.

An HP12x74 is a bearing pile section approximately 12 inches deep and weighing 74 pounds per foot. bearing piles are made from regular W rolls but with thicker webs to provide better resistance to the impact of pile driving.

An M8x6.5 is a miscellaneous section, 8 inches deep, weighing 6.5 pounds per foot. It is one of the groups of doubly symmetrical. H-shaped that cannot be classified by dimension as a W, S, or H.P.

Miscellaneous has a different shape from the other sections.

Cold-formed shapes.

The previous section was about the hot-rolled section. The next slide shows the cold-formed shapes. The cold-formed shapes include Channel, stiffened channel, Zee, stiffened Zee, hat, and sigma. An angle section can also be formed for a cold-formed section.

The PDF for this post can be viewed or downloaded from the following link.

The next post will cover the different types of structural loads and introduce LRFD and ASD design methods.

If you want to see the major changes between CM #14 and CM#15 regarding the different grades of steel and their uses for steel elements and bars, please refer to post 1A.

This is a link to a very good reference, Chapter 1 – Introduction–An Overview of the AISC Steel Construction Manual, 14^th Edition

This is a link to a very good reference, Chapter 1 – Introduction–An Overview of the AISC Steel Construction Manual, 15^th Edition

This is a link to a very good reference, Chapter 1 – Introduction–An Overview of the AISC Steel Construction Manual, 16^th Edition.