The document discusses structural steel as a critical building material, detailing its types, properties, and manufacturing methods. It highlights various structural steel shapes used in construction and outlines its applications in buildings, bridges, and towers due to its strength and lightweight properties. Additionally, the document emphasizes the principles of structural design, focusing on safety, reliability, and economic considerations in steel construction.

1. Module 3
Structural Steel.
Contents:
6) Structural Steel as a Building Material: Types, Properties, Uses and Manufacturing
Methods.
7) Steel Construction: Steel Column/Beam Construction; Principles and Methods of
Construction.

2. What is Structural Steel?
• Structural Steel is a special kind of Steel. It is used for construction purposes.
• Due to its rigidity and high strength-to-weight ratio.
• Structural Steel is used in houses, warehouses, airplane hangars, educational
facilities, bridges, stadiums, etc.
• Structural Steel is Steel that contains carbon, not more than 2.1%. These are
also called Carbon Steel, and structural Steel typically has a carbon content
of less than 0.6%.

3. • Properties of Structural Steel :
a) Density: The density of Structural Steel is 7750 to 8100 kg/m3.
b) Young’s Modulus of Elasticity: Typical values for structural steel range from 190-210 GPa
c) Poisson’s ratio: For structural Steel, the acceptable value ranges from 0.27 to 0.3.
d) Tensile strength: Structural Steel has high tensile strength, so it is preferred over other
construction materials.
e) Yield strength: The yield strength, also known as the yield point, is the stress at which an
object permanently deforms. When stress is removed, it does not revert to its former shape.
Carbon structural steel has a yield strength ranging from 187 to 758 MPa. The values of
structural Steel constructed of alloys range from 366 to 1793 MPa.
f) Shear strength: The shear strength of steel structure is specified at the failure under shear
stress, and it is about 0.57 times the yield stress of structural Steel.
g) Hardness: The resistance of an object to shape change when force is applied is referred to as
hardness. There are three different types of hardness tests. Scratch, indentation, and
rebound are all terms used to describe the process of scratching and indenting, and the
hardness of structural Steel manufactured with alloys ranges from 149 to 627 kg. Carbon
structural steels have a weight range of 86 to 388 kg.

4. • Properties of Structural Steel :
a) Melting point: Because there are so many different types of structural Steel, there is no
standard melting point.
b) Specific heat: The amount required to raise an object’s temperature by a particular quantity
is known as specific heat or heat capacity. A higher specific heat value indicates that the
thing is more insulating. The units of measurement are Joules per Kilogram Kelvin. Specific
heat for carbon structural steel ranges from 450 to 2081 J/kg-K, while for structural alloy
steel, it ranges from 452 to 1499 J/kg-K.

5. Structural Steel Types and Grades:
• There are multiple varieties of structural
steel, each designed for specific
applications.
• Structural steel comes in various shapes
and grades, chosen based on the
project’s requirements.
• The classification of structural steels is
determined by the shape of their cross-
sections, with commonly used figures
including I, T, and C shapes.
• Additionally, the mechanical properties
of the steel are directly influenced by
its grade.

6. Types and Grades:
a) Carbon steels.
b) High-Strength Low-Alloy Steels
c) Forged Steels
d) Quenched And Tempered Alloy Steels

7. Types and Grades:
a) Carbon steels.
• Carbon steel is a type of steel that contains carbon as the primary alloying element (such
as zirconium, cobalt, nickel, etc.), with other elements present in smaller amounts (Mn:
1.6%, Si: 0.6%, Cu: 0.6%).
• It is the most common type of steel, accounting for over 90% of all steel produced.
• Carbon steel comprises iron and carbon, with carbon content ranging from 0.05% to
2.1% by weight.
• Based on carbon content, the category of carbon steel regular as:
a) Low-carbon steel (< 0.3%)
b) Medium-carbon steel (0.3-0.6%)
c) High carbon steel (0.6-1%)
d) Ultrahigh carbon steel (1.25-2%)
• Carbon steel is mostly used in structural pipes and tubing.
• However, it is important to note that carbon steel is susceptible to corrosion.

8. Types and Grades:
a) Carbon steels.

9. Types and Grades:
b) High-strength low-alloy (HSLA)
• steel is a type of alloy steel that provides better mechanical properties or
greater resistance to corrosion than carbon steel.
• High-strength low-alloy steels vary from other steels in that they are not made
to meet a specific chemical composition but rather specific mechanical
properties.
• HSLA steels are typically made with low levels of alloying elements, such as
manganese (up to 2%), vanadium, titanium, molybdenum, or boron. These
elements can be added singly or in combinations to achieve the desired
properties.
• Overall, High-strength low-alloy steels are more corrosion-resistant than
carbon steel, particularly atmospheric corrosion.
• It is mostly used in structural shapes and plates.

10. Types and Grades:
b) High-strength low-alloy (HSLA)

11. Types and Grades:
c) Forged Steels :
• Forged steel is a type of steel that has been
shaped by hammering or pressing it into a
desired shape. This process is called forging.
• Forged steel is typically stronger and more
durable than other types of steel, such as cast
steel or rolled steel.
• Forging is accomplished by heating the steel to
a high temperature and applying pressure.
• The pressure causes the steel to deform and
flow into the desired shape.
• Forged steel is often used to produce gears,
bearings, shafts, hinges, valves, and other
components.

12. Types and Grades:
d) Quenched And Tempered Alloy Steels
• Quenched and tempered alloy steels are a type of steel subjected to a heat
treatment process. This process gives the steel increased strength, hardness,
and toughness.
• Quenching involves heating the steel to a high temperature and then rapidly
cooling it in a liquid, such as water or oil. This causes the steel to form a hard
martensitic microstructure.
• Tempering involves reheating the quenched steel to a lower temperature and
slowly cooling it. This softens the martensitic microstructure and makes the
steel more ductile.
• Quenched and tempered alloy steels are commonly used in construction
buildings, as well as for shafts and bolts, and in the mining industry.

13. Types and Grades:
d) Quenched And Tempered Alloy Steels

14. 3. Standard common structural steel shapes
• Structural steel shapes are defined by many standards worldwide, including
angles, tolerances, dimensions, and cross-sectional measurements. These
standards also name the different steel shapes. Many sections are formed by
hot or cold rolling, while others are made by welding together flat or bent
plates.
• Here are standard common structural steel shapes:
1. L- shape: is often used as a corner section in construction, industry,
commerce, transportation, or mining.
2. U-shape: two sides parallel to the correct angles resemble the shape of the
letter “U”. This type has relatively high durability.
3. C-shape: has a cross-section resembling the letter “C”; this form is used to
make purlins below the roof with a supporting effect.
4. Z-shape: there is a cross-section resembling the letter “Z”, similar to the form
of “C”, this form is also mainly used to make purlins.

15. 3. Standard common structural steel shapes
5. Tubular hollow cross form: tubular hollow cross sections are highly resistant
to twisting and are used mainly in multi-axis constructions.
6. Flatform: often referred to as plates, used to attach to construction parts to
enhance bearing strength.
7. Rectangular hollow cross-section: The rectangular open cross-section
resembles the circular hollow cross-section. This type is often used in many
mechanical and construction steel industries.
8. Square hollow cross-section: Since this form is difficult to combine with
other forms, the square open cross-section is used only as a column or pillar of the
building.
9. Taper-shaped beams and columns: popular in industrial prefabricated steel
buildings.

16. 3. Standard common structural steel shapes

17. 3. Standard common structural steel shapes
• Typically, round bars tend to be thicker than rods, with diameters ranging from 1/8″ to 6″, while rods range in diameter from 1/16″ to 1″.

18. 3a. Built-up Sections:
• Typically, round bars tend to be thicker than rods, with diameters ranging from 1/8″ to 6″, while rods range in diameter from 1/16″ to 1″.

20. 5. What is structural steel used for?
Structural steel is typically used in a variety of applications, including:
a) Buildings: Structural steel is the backbone of many modern buildings, from skyscrapers
to homes. It is used to create the frames that support the weight of the walls, floors, and
roof.
b) Bridges: Structural steel is also used to build bridges, which can be very long and span
large distances. It is strong enough to support the weight of vehicles and pedestrians,
and it can also withstand the forces of wind and water.
c) Towers: Structural steel is used to build towers, such as telecommunications towers and
wind turbines. These towers must be able to withstand strong winds and other extreme
weather conditions.
d) Other structures: Structural steel is also used in a variety of other structures, such as
warehouses, stadiums, and industrial plants.
e) Structural steel is a versatile and durable material that is essential for modern
construction. It is strong, lightweight, and relatively inexpensive, making it an
ideal choice for a wide variety of applications.

21. 5. What is structural steel used for?
Structural steel is typically used in a variety of applications, including:

22. 5. What is structural steel used for?
Structural steel is typically used in a variety of applications, including:

23. 6. How is it made?
• While the shorthand version of how structural steel is created involves heating iron up
and adding certain substances to achieve specific properties, the long version is much
more involved.
• Raw iron is the chief ingredient, but it is rarely found pure in nature. Most often it
already contains carbon, but usually in too high a concentration. Some carbon needs to
be removed, but not all. Because of that, the manufacturing of steel products can be an
involved process.
1. First, the raw iron ore is crushed and sorted. There are a number of different
refining processes, all designed to sort out the best grades of iron, usually around
60 percent.
2. Ore is loaded into a blast furnace from the top and heated, while hot air is blown
into the furnace from the bottom. The reaction that takes place begins to remove
impurities as pure iron sinks to the bottom of the furnace.
3. The molten iron is drawn off and is further heated to allow the inclusion of other
substances, such as manganese, that deliver different properties to the finished
steel product.

24. • How is it made?
• Once the steel has been created, it is formed into a number of different
configurations, depending on how it will be used. Beam, channel, angle, plate
and hollow steel tube are the most common.

25. Part 7) Principles and Methods of Construction :
• Steel structure design principles refer to the basic principles that should be
followed in designing steel structure buildings.
1. The most basic tenets are safety and reliability, which means that the
structural design must ensure the stability and strength of the structure
under the specified working load.
2. In addition, the economy and aesthetics of the system also need to be
considered.
3. Comprehensive structural analysis and calculations are required during the
design process to ensure the structure can withstand the necessary loads and
external forces, such as seismic forces.
4. Relevant steel structure design codes and standards also need to be followed.
5. Steel structure design requires advanced design tools and technologies, such
as computer-aided design software and three-dimensional modeling
technology, to improve design efficiency and accuracy.

26. Part 7) Principles and Methods of Construction :