WHAT YOU WILL GAIN FROM THIS PRESENTATION?
• The primary objective of this
presentation is to reflect the
latest updates in using structural
steel in modern projects.
• Identify the advantages of steel
for design & construction.
• In addition to show some
important structural steel details
& requirements.
CONTENT
PART 1
• STRUCTURAL STEEL HISTORY
• FAMOUS LANDMARKS
• ADVANTAGES OF STRUCTURAL STEEL
• DISADVANTAGES OF STRUCTURAL STEEL
• STANDARDS & CODES
• STEEL SECTIONS
• ASTM SPECIFICATIONS FOR STEEL SECTIONS
• ASTM SPECIFICATIONS FOR BOLTS
• WELDING
• STRUCTURAL STEEL DESIGN METHODS
• CONSTRUCTION PROCESS
PART 2
• STRUCTURAL SYSTEMS
• MULTI-STOREY BUILDINGS
• LONG-SPAN STRUCTURES
• FIRE PROTECTION SYSTEMS
• CORROSION PROTECTION SYSTEMS
MODERN STRUCTURAL STEEL HISTORY
• The use of steel for structural purposes
was initially slow.
• The Bessemer process in 1855 made steel
production more efficient, and cheap
steels.
• High tensile and compressive strengths
plus good ductility were available from
about 1870.
• In the United States, the first steel framed
building was the Rand McNally Building in
Chicago, erected in 1890.
• The Royal Insurance Building in Liverpool
was the first to use a steel frame in the
United Kingdom, erected in 1903.
Rand McNally Building
Royal Insurance Building
FAMOUS LANDMARKS OF STEEL STRUCTURES
Statue of Liberty
Location: U.S.A
Completed: 1886
Eiffel Tower
Location: France
Completed: 1889
FAMOUS LANDMARKS OF STEEL STRUCTURES
Golden Gate Bridge
Location: U.S.A
Completed: 1937
Atomium Building
Location: Belgium
Completed: 1958
FAMOUS LANDMARKS OF STEEL STRUCTURES
Oita Stadium
Location: Japan
Completed: 2001
Swiss Re Tower
Location: England
Completed: 2004
ADVANTAGES OF STEEL AS STRUCTURAL MATERIAL
• Ductility property; that means extensive deformation without
failure.
• High strength of steel per unit of weight; this fact is great
importance for long-span & tall buildings.
• Sustainable; steel is the most recycled material on the planet,
accordance to international organizations, such as (AISC).
• Additions to existing structures.
• Speed of erection.
DISADVANTAGES OF STEEL AS STRUCTURAL MATERIAL
• Brittle fracture; if steel lose its ductility the brittle fracture may
occur at places of stress concentration.
• Fatigue; steel strength may be reduced if the steel is subjected to
a large number of stress reversal.
• Susceptibility to buckling.
• Maintenance cost.
• Fireproofing cost.
Several organizations publish recommended practices for structural
steel, such as:
ASTM: American society for testing & materials.
AISC: American institute for steel construction.
AISI: American iron & steel institute.
AWS: American welding society.
STANDARDS & CODES
STEEL SECTIONS
• Hot-rolled shapes.
Suitable for primary members
(columns, girders, beams…etc.)
Hot-rolled steel column
Hot-rolled steel beam
STEEL SECTIONS
• Cold-formed shapes.
Suitable for secondary members
(purlins, girts, studs…etc.)
Cold-formed steel purlin
Cold-formed steel girt
STEEL SECTIONS
• Built-up shapes.
Suitable for primary members
(columns, girders, beams…etc.)
Built-up steel column
ASTM SPECIFICATIONS FOR STEEL (SHAPES & PLATES)
• Carbon steel; carbon percentage (0.15 to 0.29)%, the very
common steel A36 (Fy=36ksi & Fu=58ksi); suitable for buildings
& bridges.
• High strength Low-alloy steel; this type has much greater
atmospheric corrosion resistance than the carbon steel. A572
Gr.50 (Fy=50ksi & Fu=60ksi); suitable for buildings & bridges.
Note:
Fy: Yield stress.
Fu: Ultimate strength.
ASTM SPECIFICATIONS FOR (BOLTS & ANCHOR BOLTS)
Common bolts:
• A307: (Ft=20ksi) (for secondary connections & anchor bolts).
• A325: (Ft=44ksi) (for primary connections & anchor bolts).
• A490: (Ft=54ksi) (for primary connections & anchor bolts).
Note: Grade of bolt
Ft: Tension stress.
All bolts shall be galvanized.
WELDING
• Welding is a process in which metallic
parts are connected by heating their
surfaces to fluid state, and allowing the
parts to flow together and join.
• The two main types of welds
are fillet & groove welds.
• Welding strengths accordance
to AWS standard:
E60XX, E70XX to E110XX
E60XX: Electrode 60ksi (410Mpa)
1st X : Welding position
2nd X: Coating current & condition
STRUCTURAL STEEL DESIGN METHODS
American institute for steel construction (AISC) presented two
structural design methods:
• ASD: Allowable stress design method.
• LRFD: Load & resistance factor design method.
Note:
You cannot switch between the two
design philosophies in a given project!
CONSTRUCTION PROCESS
1. Engineering (Design).
2. Engineering (Detailing).
3. Fabrication.
4. Erection.
Discussion
• The structural designer arranges
the structural systems & their
parts so that they satisfactorily
support the loads.
• Maintaining the architectural &
MEP requirements.
• Finally, present that in design
drawings & reports.
1. Engineering (Design)
• During the detailing process, the
detailer develops shop drawings
for each member & part for
fabrication & erection purposes.
• Each member is assigned a
unique piece mark for
identification & tracking.
• The detailer also prepares a
(BOM) list.
2. Engineering (Detailing)
3. Fabrication
• Raw steel used for fabrication shall well-stored in stockyard.
• After preparation of raw material; structural steel members are
fabricated by precisely cutting, shearing, punching, drilling,
bending, fitting and welding in order to produce the
configurations detailed in the shop drawings.
• Each member is labeled with a piece mark, length, and job
number for identification & tracking.
3. Fabrication (Continue)
• Surface preparation of fabricated members to be ready for
applying paint or galvanization.
• After fabrication, finished structural steel members are stored in
the storage yard according to erection sequences.
• The practice of planning and storing by sequence improves the
efficiency of loading, delivery, offloading and erection.
4. Erection
• Anchor bolts are placed in exact locations, & accordance to
erection drawings.
• Cranes are placed in suitable locations.
• The structural steel members are hoisted into position &
preliminary bolted.
4. Erection (Continue)
• Temporary bracing is used to provide lateral stability to the
structure.
• Plumbing up the structure,
• Finally bolt-up using torque - wrench.
GENERAL STRUCTURAL SYSTEMS
Rafter
Column
Ground Beam
Bracing
Stringer Beam
For Staircase
Purlin
Foundation System
Studs
Girt
Framed Openings
Floor Beams
Runner
STRUCTURAL SYSTEMS
The material of the next few slides gives a general idea for two types
of structural steel systems:
1. MULTI-SOREY BUILDINGS.
2. LONG-SPAN STRUCTURES.
• Office buildings, hotels, apartments &
other multi-storey buildings are quite
common at present time!
• All of these buildings have the same
structural systems:
1.A. Gravity loads resisting system.
1.B. Lateral loads resisting system.
Discussion
1. MULTI-STOREY BUILDINGS
The most common types of floor systems currently used for (GLRS) are:
Cast in situ concrete slabPrecast – concrete planksConcrete fill on metal deck
21Supporting system option:
1- Girder or beam.
2- Open web steel joist.
* The spacing of columns
depends on the load-bearing
resistance of the floor
structures. It can vary from 3
to 12m. (With Limitations).
1.A. GRAVITY LOADS RESISTING SYSTEM (GLRS).
Open web joist systemFloor truss systemFloor beam system
Shear studsDuctwork & piping systemDuctwork & piping system
1.A. GRAVITY LOADS RESISTING SYSTEM (GLRS).
The most common types of frame systems currently used for (LLRS) are:
Braced frame by bracings or shear wallRigid frame
1.B. LATERAL LOADS RESISTING SYSTEMS (LLRS).
Other samples of (LLRS) frame systems:
Braced frameRigid frame
1.B. LATERAL LOADS RESISTING SYSTEMS (LLRS).
• When it becomes necessary to use very
large spans between columns as for
hangars, halls, exhibitions, auditoriums,
hotel ballrooms, theaters, stadium
roof…etc. The usual skeleton
construction may not be sufficient. The
below systems are the most common
for these long-spans:
2.A. Girders.
2.B. Vierendeel girders.
2.C. Rigid frames.
2.D. Arches.
2.E. Trusses.
2.F. Space structures.
2.G. Latticed shells.
Discussion
2. LONG-SPAN STRUCTURES
• Girders are large I or box-shaped.
• Typically used for long-span floor
in buildings, bridges & roof
systems.
• Suitable for spans up to 20m.
(With Limitations).
2.A. GIRDERS
• Vierendeel girder is moment
truss with or without diagonals.
• Typically used for long-span floor
in buildings, bridges & roof
systems.
• Suitable for spans up to 30m.
(With Limitations).
2.B. VIERENDEEL GIRDERS
• Rigid frame consisting of
members joined together with
moment connections.
• Used for hangars, factories,
warehouses & roof systems.
• Suitable for spans up to 90m.
(With Limitations).
2.C. RIGID FRAMES
• Arches consisting of members
joined together with moment
connections.
• Used for hangars, factories,
warehouses & roof systems.
• Suitable for spans up to 40m.
(With Limitations).
2.D. ARCHES
• Trusses consisting of members
joined together with pinned
connections.
• Used for long-span floors,
hangars, bridges & roof systems.
• Suitable for spans up to 100m.
(With Limitations).
2.E. TRUSSES
• Space structures consisting of
members joined together in
three dimensional.
• Used for long-span canopies,
domes & roof systems.
• Suitable for spans up to 120m.
(With Limitations).
2.F. SPACE STRUCTURES
• Latticed shells consisting of
members joined together
diagonally in three dimensional.
• Used for long-span canopies,
domes, vaults & roof systems.
• Suitable for spans up to 50m.
(With Limitations).
2.G. LATTICED SHELLS
• GypsumThis material takes several forms
to be used for fire protection,
such as:
(Plaster applied over metal lath
or gypsum lath, & Wallboard)
FIRE PROTECTION SYSTEMS
FIRE PROTECTION SYSTEMS
• Spray-AppliedThe most widely used
materials are (mineral fiber and
cementations materials) that are
spray applied directly to steel
members.
• Suspended CeilingWide variety of proprietary
suspended ceiling systems are
also available for protecting
floors beams and girders.
FIRE PROTECTION SYSTEMS
• Concrete & BricksOnce widely used for fire
protecting structural steel, is not
particularly efficient for this
application because of its weight
and relatively high thermal
conductivity.
As a result, concrete is rarely
used when the purpose is fire
protection only!!
• Intumescent CoatingsIntumescent coatings are epoxy based paint-like mixtures applied
to the primed steel surface, which at elevated temperatures
expand to many times their applied thickness.
CORROSION PROTECTION
• Typical Atmospheric corrosion occurs when steel is exposed to
a continuous supply of water and oxygen.
• The rate of corrosion can be reduced if a barrier is used to keep
water and oxygen from contact with the surface of bare steel.
• Painting is a practical and cost effective way to protect steel
from corrosion, by using (Polyester, Alkyd & Epoxy
paints…etc.).
• Dry film thickness (DFT) & number of coats depends on type of
structure, environment …etc.
• Each paint color has a unique RAL number.
CORROSION PROTECTION
• Galvanized steel is another alternative protection system.
• Duplex System, Galvanized Steel & Painted.
• Electrical methods (Cathodic & Anodic) protection systems are
suitable for marine steel structures.