Part 1: General

STEEL 1

Introduction Classes of Steel

▪ Steel is an alloy of Iron and other elements primarily Carbon
Low Carbon Steel:
▪ Classified into 4 categories on basis of the carbon content. ▪ Carborn content
✓Low carbon steel being 0.03 – 0.3% by
✓Medium carbon steel weight.
✓High carbon steel ▪ Mild steel falls in
✓Ultra-High carbon steel this category, with
carbon content of
▪ The strength increase with increase of the carbon content.
0.05 – 0.25%.
▪ However high carbon content makes steel less malleable. ▪ Application –
✓ Construction
✓ Car bodies

Classes of Steel Classes of Steel

High Carbon Steel:
▪ Carborn content
Medium Carbon Steel: being 0.61 – 1.0% by
▪ Carborn content being 0.31 weight.
– 0.6% by weight. ▪ Applications:–
▪ Applications:– Shafts, Axles, Springs, high
gears, rails & railway strenthen wires,
wheels
edged tools
▪ Hard to the extenet
that it cannot be
welded

Classes of Steel Attributes of Steel

1. Tensile Strength.
Ultra-high Carbon Steel:
▪ Carborn content being 1.25 ▪Steel has high tensile strength
– 2.0 % by weight. ▪The term tensile strength refers to the amount
▪ Applications:-knives, axles, of stretching (tensile stress) that a material can
punches. withstand before breaking or failing.
▪ Cannot be welded
▪However, it is weak in compression
Attributes of Steel Attributes of Steel
2. Shear Strength
▪ Shear strength of a material is specified as the SHEAR STRENGTH

point that it would failure under shear stress.

▪ A shear load is a force that tends to produce a
sliding failure on a material along a plane that is
parallel or perpendicular to the direction of the
force.
▪Two types of share stress
✓Horizontal shear stress
✓Vertical shear stress

Attributes of Steel Attributes of Steel

3. Hardness. 4. Malleability.
▪Steel is hard material ▪Malleability is quality of material such that it can
be shaped into something else without breaking.
▪Hardness is a measure of the resistance to
Also referred to as plasticity.
localized plastic deformation induced by
either mechanical indentation or abrasion. ▪Steel with low carbon, such as mild steel which
is widely used in construction is
malleable/flexible. It can resist strong winds and
earthquakes.

Attributes of Steel Attributes of Steel

5. Ductile. 6. Rust Resistance
▪ Ductile is quality of material such that it can be:- Steel is prone to rust and where is exposed to
✓ drawn out into a thin wire. humidity or used in a marine environment it
✓deformed without loosing its strength. requires to be treated for protection against
▪Mild Steel is a ductile material. It does not fail corrosion:
suddenly. Under pressure it would bend or get ▪ Galvanized steel - Coating with zinc
deformed giving warning of impending failure. Steel ▪ Stainless steel – Composed of 10% chromium
structures rarely fail. ▪ Application of surface coating material on site such as
▪Steel can withstand a great deal of deformation before paint.
rupture.

Attributes of Steel Attributes of Steel

7. Conductivity
Steel is a good conductor of heat and electricity. 9. Durability:
▪ Steel is a durable
8. Temperature Resistance material
Steel lose strength when exposed to high ▪ It is not attacked by
temperatures. It needs to be protected from high pests, insects and rodents
temperature by covering with heat resistant boards, ▪ It does not rot, shrink,
concrete or spray on deform on exposure to
moisture
▪ Non- combustible
▪ The major threat to steel
is corrosion
Attributes of Steel Steel Rolling Methods
There are two ways in which stell is rolled, cold and hot,
and which determines some features of the final product.
10. Sustainability:
▪ Cold Rolled Steel: Milled by way of asserting pressure at
▪The major advantage of room temperature.
steel is the ability to ✓Smooth surface finish
recycle effectively, without ✓20% harder than hot rolled steel
destroying or losing any of ✓More expensive
its physical properties in the
recycling process. ▪Hot Rolled Steel: Milled at temerature above its
crystallization level; above 10000F.
▪Left-overs that ends up in
✓Rough surface finish, as a result unevenly shrinking during cooling
landfills are oxidised (Rust) Recycled steel beams
✓More malleable and easy to form
and become part of the soil.
✓It has lower production cost

Types of Steel Structures

Two Types
Light weight steel structures
✓ Members are made of 1-3mm thick steel sheet bent to C-
or Z-sections and treated to protect it from rusting.

Heavy steel structures

✓ Members are in form I-section, Rectangular Hollow
Section (RHS) or Circular Hollow Section (CHS), with
thickness varying from 3mm to 12mm. Standard lengths
being 6 and 12m.

Light Weight Steel Structures Light Weight Steel Structures

The technology evolved from timber framed ▪ Light Weight Steel is used in construction of walls,
buildings. suspended floors and roofs.
▪ Steel is cold rolled to create long thin sheets
▪ Since steel susceptible to rusting, foundations elements
channelled through rollers to create C or Z are constructed of concrete and masonry materials.
formations capable of holding heavy loads. ▪ Steel is weak in compression and to attain desired
▪ For protection against rust, members are compression strength the building elements (walls
galvanized steel; i.e. Mild steel coated with zinc. panels, floors structure, roof trusses) are constructed
of framed members
▪ Building elements may be fabricated in factory or
on site. When fabrication is done at factory,
members are delivered on site pre-cut, pre-
punched and pre-marked.

Light Weight Steel Structures Light Weight Steel Structures

▪ Framing makes the building able to withstand Connection of
earthquakes, high winds, heavy snow and hurricanes Members:
better than other materials.
✓ Self drill/self tapping
▪ For insulation ( heat/sound) the wall frames are screws
sandwiched between other materials.
✓ Rivets
▪ In the event of a fire outbreak this improves the
amount of time available for egress prior to structural ✓ Welding where strong
collapse joints are required
✓ Connectors, are used
to fasten different
members together
Light Weight Steel Structures Light Weight Steel Structures
Substructure: walls:
▪ The foundation are constructed of shallow strip The structure is constrcuted of
concrete/masonry in areas of uniform ground otherwise pile steel frame.
foundation are used.
Externally the steel structure
▪ Wherethe structure is anchored on strip foundation the floor is is cladded with weather
made of concrete. The wall members are anchored using bolts resistsnt materials such as
to the concrete floor. bricks, timber boards,cement
▪ If the foundation is pile type the floor is constructed of steel fibre boards, fibre glass,
members. Discussed under suspended floor slide later. Alucobond
▪ Due to the light weight nature of steel material the
Internally the wall may be
foundation are less elaborate as compared for concrete or
finished with materials like
masonry construction
gypsum or any other
depending on the designers
choice

Light Weight Steel Structures Light Weight Steel Structures

walls:
▪When the steelframe is
cladded on both sides a
cavaity is created.The
cavity may be filled with
heat insulation material or
sound insulation material or
both depending on the
need.
▪Metal members are
punched to provide
passages for services

Light Weight Steel Structures Light Weight Steel Structures

Suspended Floors: Roof
The structure is Construction.
constrcuted of steel frame. ▪ Roof is
Metal members are punched constructed in
to provide passages for form of trusses
services ▪ Cover material
must be light
Light weight steel is a good
weight such iron
conductor of sound. For
sound insulation the cavity sheets or stone
may be filled with sound coated metal
insulation material to tiles.
dampen foot step sound.

Light Weight Steel Structures Light Weight Steel Structures

Advantages Advantages
▪ Time: Short construction period. ▪ Simple technology: construction can be done by
▪ Environmental Protection semi-skilled labour force
▪ Recycling of materials ▪ Easy handling: Site hoisting can be done by human
▪ Low energy consumption during transportation and site labour. This eliminates the need of cranes.
hoisting ▪ High strength-to-weight keeps the overall weight to
▪ Cost: Steel is expensive but cost savings are less that 50% of masonry/concrete structure. This
realized through: helps in cutting the cost of foundation construction
▪ Shorter building schedules, considerably
▪ Reduced material waste
▪ Low cost of sub-structure
▪ Low transport and on site handling cost
Light Weight Steel Structures
Drawbacks
▪ Unlike other materials like masonry and concrete
steel is not widely available
▪ Since steel is a good conductor of heat, the frames
create a thermal bridges.
▪ The construction tend to be have a poor sound
privacy. This necessitates installations of sound
insulation materials which in turn increase the cost.
▪ Steel on its own is expensive.

HEAVY STEEL STRUCTURES

Steel Frame Structural Elements Hollow Sections

In construction of building, steel is used in the Hollow Sections:
following building elements. ▪ Is a metal profile which is internally hollow.
▪ Columns ▪ Members can be circular, square, or rectangular sections.
▪ Wall frames ▪ Rectangular and square sections are also commonly called tube
▪ Beams steel or box section.
▪ Floor decking ▪ The dimensions are based on exterior dimensions of the profile.
▪ Roof Trusses ▪ Thickness varying from 3mm to 12mm, with Standard lengths
being 6 and 12m.

Dimensions given as bxhxt

Hollow Sections Hollow Sections

Rectangular/Square/Circular Hollow Sections: Rectangular/Square Hollow
Sections:
▪ Rectangular sections, are commonly used in ▪ RectangularHollow Sections (RHS) is the
welded steel frames where members experience next best, after circular and square
loading in multiple directions. sections, in terms of structural efficiency.
▪ Square and circular members have very efficient ▪Both RHS and SHS are increasingly
becoming popular in tall buildings, as they
shapes for multiple-axis loading as they have are easily fabricated and erected.
uniform geometry along two cross-sectional axes, ▪Welded tubes of circular, rectangular or
and thus they have uniform strength square sections are very satisfactory for
use as columns in a long series of windows
characteristics. This makes them good choices and as short columns in walkways and
for columns. They also have excellent resistance covered warehouses. (minimal loading use)
to torsion. ( torsion - action of twisting or being ▪For many structural applications the
weight of hollow sections required would be
twisted.) only 50% of that required for open profiles
like I or C sections for the same loading.
 Hollow Sections Hollow Sections
Circular Hollow Sections: Elliptical Section:
▪ They are perhaps arguably the most efficient
under compression.
▪ The only short coming they present in use is that
they are difficult in connecting with other
members. For this reason, they are not widely used
in steel frame structures.

Hollow Sections Hollow Sections

Hollow Sections:
Elliptical Hollow Sections (EHS):
▪ This is a new product in the market. ▪Are preferred in exposed structures due to their
▪ Combines the merits of traditional circular hollow architectural aesthetics, although elliptical HSS are becoming
sections (CHS) and rectangular hollow sections (RHS), more popular in exposed structures for the same aesthetic
reasons.
in terms of strength.
▪ The smooth streamlined shape is not only ▪They can also be used as beams, although wide flange shapes
architecturally appealing but also favourable for are in many cases more efficient structural shapes for this
reducing wind resistance. application.
▪ Examples of projects incorporating EHS include the
coach station at Heathrow Terminal 3 in the UK.

Angle Sections
Beam Sections
▪Angle section takes an L shape, with two legs that come together
at a 90-degree angle. Angle section members may have equal or
Beam Sections
unequal leg sizes. ▪ Beam sections are classified is H- beam, I- beam C-/ U- beam and
T-beam.
▪Angle section is better as a tension member and therefore are ▪ The names are derived from the appearance.
commonly used as bracings in the frame construction. ▪ The terms ‘flange’ and ‘web’ are used to denote different parts of
▪They are also easy to connect to other members. the beam. See image below.
▪Sizes expressed as length of 1st leg x length of 2nd leg x
thickness eg. 50x50x4mm or 50x75x4mm

Beam Sections Beam Sections

Beam Sections Beam Sections
They are produced in a number of wide shapes and sizes. However C- or Channel Beams
the common ones are I-, H- C & T - Sections. The C or Channel Beam has a C-shaped cross section.
I-Beam They contain sloped inner flange surfaces that appear
The I beam is so called because it resembles the letter I when one only on one side of the beam. Typically Channel Beams
views at it directly in the frontal position. They can have either are used as a support for lighter loads. As such
tapered flanges or wide flanges. They are commonly used where high they’re a preferred choice in residential construction,
loads are expected. rather than for heavy construction purposes.
H-Beams
Similarly to I-Beams, H-Beams are so called because they resemble T- Beams –The name is derived
the capital letter ‘H’ when viewed at from the front. They have long from its shape which resembles
flanges and are usually longer and heavier than I-Beams. Often used like letter T
in larger constructions such as skyscrapers or bridges. They provide
greater strength in a wide spans.
 Beam Sections Steel Frame Structural Elements
Steel beams ensure the integrity of the structure and Substructure:
relentless strength and support.
Steel is not widely used in sub-structure construction. This is to
The huge strength of steel beams reduces the need to include avoid the risk of rusting in the event of exposure to moist condition
many support structures, saving time and money, and making which is prevalent in sub-structure works.
the structure more stable. - Wide spans and large
The substructure is ordinarily done in concrete or masonry
uninterrupted spaces
materials. Steel columns are then anchored to the concrete member
NOTE: The name, beam section, is rather misleading, because at ground or higher-level using plates and bolts.
the same sections are used for columns.
Base plates are welded to the end of columns. The most desired
shapes of base plate are square and rectangle, because such plates
provide largest spacing between the bolts which is desirable.

Steel Frame Structural Elements Steel Frame Structural Elements

Columns Columns
▪Hollow sections, circular, square or rectangular cross-section are
used as column in low rise building. ▪When the available sections are not
able to support the loading, a suitable
▪In the case of high rise building the commonly used sections are
I and H profiles section may be built-up either by
lacing or battening two sections
▪Sometimes hollow sections are filled with concrete, giving an separated by a suitable distance.
increase in strength and, at the same time, achieving significant
fire resistance. ▪When compression members are
required for large structures like
bridges, it will be necessary to use
built-up sections.
Built - up or fabricated Compression
Members

Steel Frame Structural Elements Steel Frame Structural Elements

Suspended Floor Slabs
BRACING
▪Suspended slabs are supported by
▪Not only do the column systems system of steel beams; primary,
support vertical applied loads but also, secondary and tertiary depending on
the span distances and loads.
they act like diaphragms and resist
lateral loads using bracings. ▪The tertiary beams transfer the
floor load to secondary beams which
▪Bracings are used to resist lateral in turn transfer it to primary beam.
forces imposed on structure and it The primary beams eventually
transfer the load to the columns and
transfer lateral loads to the columns to the building foundation system.
and then to the foundation.
▪Suspended slabs are grouped into
▪The bracing also acts as anchorage two types: one-way slabs which are
supported on two sides. Two-way
members for the cladding of the slabs which are supported on all four
building. sides.

Steel Frame Structural Elements steel Frame Structural Elements

Suspended Floor Slabs Composite Floor Deck
▪On top of the steel beams sits ▪The steel metal sheet may be either
a Composite deck that support trapezoidal or re-entrant. Trapezoidal
both live and dead loads. decking may be over 200 mm deep, in
which case it is known as deep decking. Trapezoidal Decking
▪The composite deck (floor
slab) generally comprises of ▪Reinforcing bars are placed in the
profiled galvanized steel metal sheet’s troughs and so are services
ducts
with insitu concrete cast over
the deck. ▪The deck sheet serves two purposes;
Image showing an axonometric
one as a permanent shuttering and
▪The concrete is reinforced of a composite floor slab
secondly as structural member by
with steel to give it tensile Re-entrant decking
directly transferring loads to
strength secondary or tertiary beams.
 steel Frame Structural Elements steel Frame Structural Elements
Composite Floor Deck Shear studs welded on Composite Floor Deck
beam top flange
Reinforcement mesh Servies infrastructure such
electrical conduits and
plumbing pipes are laid
Structural concrete floor before the concrete is
Profiled galvanized steel poured
decking

Image showing
composite floor slab
Image showing a composite
Floor slab

steel Frame Structural Elements Steel Frame Structural Elements

Composite Floor Deck Steel Members Connection Methods
▪Merits of composite deck floor There are three common methods of connecting steel
are derived from its simplicity
members in steel frame construction:
and familiarity
▪ Bolting
▪Steel floor systems are simple ▪ Welding
resulting to less labor and cost.
▪ Riveting
▪ A down stand solid web I-
section beam as opposed to a
truss, means fewer structural
elements, less fabrication ,
fewer surfaces to be fire
protected and less time to
design.

Connections of steel Members Connections of steel Members

Connection Methods Column to Column
The most common method of connecting two members ▪There are three (3) commonly used
together in heavy steel construction is the bolting system. types of joints in column-to-column
connections; splice joint, bolted butt
There are instances where two methods such as bolting, and joint and welded butt joint.
welding are used simultaneously to take care of different ▪Splice Column Joint: This is a means
forces that would be experienced by the joint. of joining of two parts of a column
using a bearing plate and bolts . The
bearing plate is laid to overlap the
position where the two members meet
and bolted. The bearing plate
transfers forces and moments from
upper member to the lower one.
Splice Joint

Connections of steel Members Connections of steel Members

Column to Column Column to Column
▪Bolted Butt Joint: This is a ▪Welded Butt Joint: This is
means of joining of two parts of a a means of joining of two parts of
column using a butt plate (end a column by way of welding the two
Plate) and bolts . Butt plates are members together. This kind of
welded to ends of the two joint is weak against moments
members. The two butt plates are (bending) forces.
bolted together forming the joint.
While the vertical forces are
directly transferred from the
upper member to the lower
member the butt plates transfer
moments (bending) forces. Butt Bolted Joint
Connections of steel Members Connections of steel Members
Column to Column Beam to Column Joints
▪Column joints are provided in every two or three There are different types of beam to column
storeys to ease erection process and to simplify steel connection which are selected based on the type
column production and deliveries. of loads imposed on the beam to column joint.
▪In cases of continuing columns joints are not done at If the joint is subjected to vertical loads only
floor levels. The distance between floor and column (shear load), simple connections are used.
joint is kept to not less than 600mm. This is done to Flexible end plate, Fin plate and Double angle
minimize the number of joints occurring at the same cleat are used.
point. At floor level is where beam to column joint occur.
Having a column-to-column joint at the same position
compromises the structural integrity of the structure.

Connections of steel Members Connections of steel Members

Flexible End Plate Connection: A length of a plate is Beam to Column connection
welded ( usually in the workshop) to the supported Fin Plate Connection: A length of a plate is welded ( usually in
member , the beam, and bolted to the supporting the workshop) to the supporting members ( column). On site the
member, the column. -- (shear joint) column, and the supported member, the beam, are bolted
together.

Connections of steel Members Connections of steel Members

Double Angle Cleat Connection: Angle cleats are Beam to Column Connection:
bolted to the web of the supported member (Beam) simple connections i.e flexible
and to the flanges of the supporting member end plate, fin plate and double
(column). angle cleat which are essentially
shear joints can be made to
moment joint by welding together
the flanges of the beam and
column.
1. Shear Joint – Bolting only

2.Moment (Rigid) joint - A

welded beam to the column. The
beam flange welds transmit full
flange strength to the column.

Connections of steel Members Connections of steel Members

Beam to Column Joints
Where the joint is subjected to both vertical loads (shear Beam to Beam Connections:
force) and torsion (twist) forces, then full depth end plate
connections and extended end plate connections are In beam-to-beam connection
recommended.
the same principles used in
beam to column connection also
apply. The type of connection
will depend on the forces being
experienced by the joint
either shear or moment or Beam-to-beam connection
both.

Full depth plate connection Extended end plate connection

 Steel Frame Structural Elements
Trusses
❑ A triangulated system of straight interconnected structural
elements.
❑ Different members experience different forces - compressive and
tensile.
❑ All forces are experienced at the joints. Thus, they play a key role
in determining the integrity of the truss.
❑ Used to support - roofs, floors and internal loading such as
services and suspended ceilings.
❑ The main advantages of using trusses are:
Roofs ▪ Long span
Acoustics ▪ Lightweight - Trusses are assumed to be of negligible weight
Thermal (compared to the loads they carry)
Fire Protection ▪ Reduced deflection (compared to plain members)
▪ Support considerable loads.

Steel Frame Structural Elements Steel Frame Structural Elements

Trusses
There are two broad categories of Trusses
trusses namely 2-D and 3-D ▪ Trusses also play key role in
form making of buildings.
2-D Truss: These are two dimensional ▪ The choice of the type of
trusses which are basically bars oriented trussing system will depend
in two dimensional cartesian systems. on:
▪ Function of space being
3-D Truss: These are three dimensional created
trusses which are basically bars oriented ▪ Expected forces
in three dimensional cartesian systems. (loading)
They are commonly referred to as space ▪ Desired form appearance
frames of the building. Long Span

Steel Frame Structural Elements Steel Frame Structural Elements

Trusses
Trusses come in many shapes depending on the building form and Pratt Truss is made by bracing
intended functions. Examples of the are: two parrelle members.
▪ Fink truss The direction of the bracing
▪ Pratt truss (N-Truss) depends on the force being
▪ Warren truss experinced. Pratt Truss –Uplift loads
▪ Incase of up-lift force the
diagnal bracing are directed
toward the supprts
Fink Truss ▪ Where as in case of gravity
forces the braces are
Fink truss: mainly used incase of short span like in residentials
directed away from the PrattTruss- gravity Load
houses.
supports. (towards the
They shape the pitched roofs common in this category of
centre)
construction.

Steel Frame Structural Elements Steel Frame Structural Elements

Pratt Truss are iused n cases ▪ Warren truss are more stong than pratt trusses.
where: ▪ They are used in areas where heavy loading are
▪ Long spans for 20 to 100m expected and at the same time the dersired span is
are required large.
▪ the desired form is flat
like the incase of floors or
flat roof

Warren Truss
Pratt trusses used in
University of manchester
 Steel Frame Structural Elements Steel Frame Structural Elements
▪ The flexibility and ▪ Space Frame also reffered
to as 3-D truss is a rigid
worksability of steel
light weight –struss.
makes it a versitle
▪ It is used in areas where
materials for form large spans are required.
making. ▪ Made of tubular stainless
▪ Steel trusses can be steel and it gives good
shaped to any shape easthetic feel for interior
to suit design. spaces such as airport
halls
Long-span, curved roof trusses
Robin Hood Airport, Doncaster

Steel Frame Structural Elements Steel Frame Structurers

Performance Improvements
Space Frame Arising from the properties of its materials steel structures
It can be made into various requires some performance enhancement in three areas:
forms, from plane to curveture ▪ Acoustics
shapes. ▪ Thermal
▪ Fire protection
▪ Corrosion Protection

Steel Frame Structures Steel Frame Structures

ACOUSTIC PERFORMANCE Acoustic performance:
▪ Steel is highly reflective and vibrates when exposed to ▪ Lightweight framed construction achieves far better
sound. This makes it a poor choice for acoustic standards of airborne sound insulation than the heavy
performance. metal
▪ However, steel construction involves an assembly of ▪ Presence of a cavity and the degree of isolation between
other materials supported by steel that can achieve the various layers of the construction improves the
impressive sound insulation ratings. performance
▪ There are two types of sound sources that need ▪ Roof cavities play key role reducing the impact of air
insulation bone sound .
▪ Airborne Sound -important for roofs and walls
▪ Floors Impact Sound

Steel Frame Structures Steel Frame Structures

Sound Insulation by Isolation - Floors
Sound insulation by
Isolation - Walls
▪ Insulation of a steel The same concept is
supported stud wall - cavity used on floors
filled with mineral wool. primarily to control
impact transmission
▪ Separation of steel frame.

▪ The bigger the gap and

insulating materials the
better the sound insulation
rating.
 Steel Frame Structures Steel Frame Structures
Thermal Insulation Fire protection
▪ This usually takes the form of applied
▪ Steel is a good conductor of heat with a heat transmittance
Fire Protection materials which
value (U-value) of 0.15W/m2K (Watts per square metre
insulates the steel from the
Kelvin)
increasing temperatures.
▪ All cold rolled (mild steel) structural steel sections which is
▪ This include:
used in steel structures have low fire resistance unlike hot
▪ Concrete Encasement,
rolled steel. The heat resistance is function of the size of
▪ Board Protection,
the section.
▪ Thin film Intumescent Coating,
▪ Although when heated to temperature experienced in a fire
▪ Spray Protection and
scenario it stiffens and looses strength.
▪ Flexible Blanket
▪ Consideration of thermal insulation is an important
consideration in steel construction Steel columns encased in
concrete

Steel Frame Structures Steel Frame Structures

Fire protection Fire protection

Spray Protection Board Protection Thin film Intumescent Coating

Steel Frame Structures Steel Frame Structures

Protection from Corrosion Weathering steel
Ways of improving the steel resistance to corrosion is by Weathering steel is a high strength low alloy steel that was
either apply a protective coat to its surface or adding other originally developed by United States Steel in the 1930s to
metal to its composition. resist corrosion and abrasion in their ore wagons
Surface Coating: Under normal atmospheric conditions they give an enhanced
▪ Paint – Applied with a base coat of primer and finishing resistance to rusting compared with that of ordinary carbon
(gloss) coat. steels.
▪ Galvanized steel – Application of Zinc coat on steel
With weathering steel, the specific alloying elements in the
Composition: steel produce a stable rust layer that adheres to the base
▪ Stainless steel -An alloy of iron and chromium. metal, which is much less porous. This rust ‘patina’ develops
▪ weathering steel – Low - alloy steel containing small under conditions of alternate wetting and drying to produce a
amounts of Copper and phosphorus metals. protective barrier that impedes further access of oxygen,
moisture, and pollutants.

Steel Frame Structures Facades

Benefits of weathering steel Wall Cladding (Façade Finish)
1. Attractive appearance
▪After the structural steel frame is
The attractive appearance of weathering steel often blends
completed, the building is cladded with
pleasingly with the environment, and improves with age skin materials.
2. Environmental benefits ▪Skin materials may be in the form of
The environmental problems associated with Volatile Organic steel, aluminum, Titanium, zinc, copper
Compound (VOC) emissions from paint coatings and the alucobond or glass.
disposal of blast cleaning debris from future maintenance ▪Each cladding material come with its own
work, are avoided unique strengths and weaknesses. The
choice is influenced by several project-
3.Cost benefits specific factors, including desired
Low maintenance and long term performance aesthetic, climatic conditions, chosen
structural system, and the construction
budget amongst others.
 Facades Facades
Cladding - Metal Cladding - Metal
▪ Metal panels can be connected together and attached to a building in a wide
▪Some Metal cladding materials are: variety of ways, each system offering different benefits in terms of
▪ Stainless steel construction complexity and aesthetic finish.
▪ Galvanized steel ▪ Some of the most widely-utilized systems are as follows:
▪ Weathering steel
▪ Metal is commonly used for non-structural, rain-screen
cladding, where the priority is to provide protection from the
elements as well as a striking external finish.
▪ The malleable nature of metal makes it easy to shape to
conform to the building form.

Facades Facades
Cladding - Metal
Cladding - Metal

Above: Weathering steel cladding at

Elevon campus by Ehrich Yanai Rhee
Chaney Architects

Left: Aliminun cladding at Essex Right: Titanium cladding at Left: Copper cladding at the Colombus
crossing by SHoP Architects Guggenheim Bilbao by Frank Gehry Museum of Art by design Group

Facades Steel Frame Structures

Cladding - Metal
Different
companies involved Further Reading:
with Portal frame steel structures.
manufacturing of
facades develop
their system
which include the
profile and fixing
mechanism

Façade Cladding
❑Façade – face of a building
❑Façades finishes
▪ Structural elements
▪ Plaster and/or paint
▪ cladding

❑Cladding – the application of one material over another

BUILDING FACADES ❑A wide range of materials are used for cladding of building walls.
Example:
• Bricks
• Stones
• Tiles
• Aluminium composite panels (Alucobond)
• Glass
• Steel
Façade Cladding Aluminium Composite Panels
❑Cladding materials play multiple roles in a building •Has many trade names such as Alucobond, alucore, aluminobond,
• Aesthetics etc.
• Protection against weather elements •Consist of 3 layers:- Outer two layers made of aluminium 0.5 -
• Insulation 1.0 mm and a core of mineral fill 2- 23mm
Mineral fill is finely divided mineral matter such as rock dust ( in this case
❑ Each cladding material come with its own unique strengths and aluminium dust). Mineral fills are normally fire resistant
weaknesses. The choice is influenced by several project-
specific factors, including desired aesthetic, climatic •Overall thickness vary from 3mm to 25mm
conditions, chosen structural system, and the construction
budget amongst others. •Continues production enabling material lengths of 9m.

❑Lecture subject •Great variety of application in construction – Facade cladding,

roofing, interior ceiling etc.
• Aluminium composite panels (Alucobond)
• Glass
• Steel

Aluminium Composite Panels Aluminium Composite Panels

Attributes
•Low weight and extremely high rigidity
•Excellent weather resistance – rust resistant (low
maintenance)
•Non- combustible
•Vibration damping (no additional sound damping needed)
•Perfect flatness
•large variety of colours

Aluminium Composite Panels Aluminium Composite Panels

Advantages
•High formability allows design freedom to architects and
interior designers
•Simple installation processing, using conventional tools (e.g.
for folding and bending –low installation cost) , enables easy
handling on-site, even with large size panels
•Light weight - low cost for substructures, fasteners and
transport
•Low maintenance
•Short construction time, adherence to schedules, low cost
Angular surfaces
Curved surface

Aluminium Composite Panels Aluminium Composite Panels

 Aluminium Composite Panels Glass Facades
Curtain wall
• Non-load bearing exterior wall that hangs off the
structure like a curtain
• Typically attached to the building’s floor slabs.
• It transfers wind loads onto the main building
structure through connections to the building’s
columns and floors.
• Designed to:-
• support its own weight.
• resist air and water infiltration,
• withstand sway induced by wind and seismic forces
• provide a thermal barrier between inside and out.

Glass Facades Glass Facades

•Every project is unique for its geographical location, climate,
client, function etc.
•Design of glass curtains is a customized exercise.
•Some factors that influence the design include solar control,
thermal comfort, glare and the ability to withstand wind and
seismic conditions.”

Glass Facades - Framing

Systems Glass Facades - Framing Systems
1. Stick Systems: 2. Unitized Systems:
▪ Assembled in the field.
▪Composed of large glass units that are assembled to frames in
▪ The support frame is made of, shorter horizontal members factory
that span between vertical mullions, creating a rectangular
system that binds the glass on all four sides. ▪Can be designed to span multiple floors or horizontal modules
▪ The support frame which can be made of steel or aluminium and incorporate openable vents and windows.
is firmly secured to the building column/beams and slabs ▪Having been assembled in a climate-controlled environment,
▪ The infill material — in this case glass — is then installed they have high-performance quality, including air and moisture
into these frames on site. protection.
▪ There are four ways to secure a piece of glass to a frame; ▪Requires heavy machinery for transportation to site and
structural silicone , toggle locked, bolted or pressure capped. hoisting in place
▪ Commonly used in low and medium raise buildings

Glass Facades - Framing

Systems Glass Facades - Framing Systems
3. Semi-Unitized Systems: 4. Spandrels:
▪ Semi-unitized systems combine some of the advantageous ▪ These are opaque cladding material that conceal the slab
features of both stick and unitized curtain wall systems. edge, columns and any mechanical systems located
between each floor.
▪ Each piece of glass is pre-bonded into a smaller frame in a
workshop. ▪ Glass in these areas is treated with a opeque film or is
incorporated into an assembly called a shadow box.
▪On-site assembly involves connecting metal-to-metal frame ▪ Spandrels are designed to either create complete
components, mediated with gaskets, harmony within the building façade or visual contrasting
▪The process is fast and safe. effects.
 Glass Facades – Anchor systems
Glass Facades – Anchor systems
There are various systems for anchoring Extruded Aluminium
glass to the building frames:
▪ Extrude aluminum
▪ Stainless steel brackets
▪ Structural silicon

Glass Facades – Anchor systems

Glass Facades – Anchor systems
Spider arm Double arm
bracket bracket

Glass Facades – Anchor systems Glass Facades – Anchor systems

Brackets.

Brackets.

Glass Facades – Anchor systems Metal Facades

▪A wide variety of Metal materials used for cladding
external building walls:
▪ Aluminum
▪ Titanium
▪ steel
▪ Stainless steel
▪ Galvanized steel
▪ Weathering steel
▪ Copper
▪ Zinc
 Metal Facades – Weathering
Metal Facades steel
Cladding - Metal Weathering steel is a high strength low alloy steel that was
originally developed by United States Steel in the 1930s to
▪ Metal panels can be connected together and
attached to a building in a wide variety of ways, resist corrosion and abrasion in their ore wagons
each system offering different benefits in terms Under normal atmospheric conditions they give an enhanced
of construction complexity and aesthetic finish. resistance to rusting compared with that of ordinary carbon
steels.
▪ The malleable nature of metal makes it easy to
shape to conform to the building form. With weathering steel, the specific alloying elements in the
steel produce a stable rust layer that adheres to the base
metal, which is much less porous. This rust ‘patina’ develops
under conditions of alternate wetting and drying to produce
a protective barrier that impedes further access of oxygen,
moisture, and pollutants.

Metal Facades – Weathering

steel Metal Facades – Weathering steel
Benefits of weathering steel
1. Attractive appearance
The attractive appearance of weathering steel often blends
pleasingly with the environment, and improves with age

2. Environmental benefits
The environmental problems associated with Volatile Organic
Compound (VOC) emissions from paint coatings and the
disposal of blast cleaning debris from future maintenance
work, are avoided
Above: Weathering steel cladding at Elevon
3.Cost benefits campus by Ehrich Yanai Rhee Chaney Architects
Low maintenance and long term performance

Metal Facades – Aluminium Metal Facades – Titanium

Aluminium Titanium
❑ Solid aluminium panels ❑ The titanium clad plate is made by
and extrusions coating steel plate with titanium
❑ Properties
❑ Properties
▪low density, high strength,
▪ Light wieght and
▪Corrosion resistance.
strong ▪Temperature resistance
▪ Weather resistant ▪Durability – low maintenance
▪ Maliable ❑ Over time, the surface layer of the
▪ Non-combustible titanium clad plate exposed to the air
▪ Durable and gradually form a zinc carbonate which
Sustainable is high-density, strong and anti-rust.
Titanium cladding at Guggenheim
Aliminun cladding at Essex
Bilbao by Frank Gehry
crossing by SHoP Architects

Metal Facades – Copper Metal Facades- Anchor systems

Properties Different
▪ Very lightweight material, companies involved
▪ High pliability (easily bent)
with manufacturing
▪ Highly corrosion resistance
of facades develop
▪ Sustainable
▪ Non-toxic their anchoring
When copper is exposed to the system which
elements, copper protects include the profile
itself by developing a patina and fixing
over time which reforms if mechanism
damaged, ensuring durability
and resistance to corrosion in Copper cladding at the Colombus Museum
virtually any atmosphere. of Art by design Group