Theory of Structure - I
Lecture Outlines
 Introduction
 History of Structural Engineering
 Forms of Structures
 Materials
 Loads
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Introduction
STRUCTURAL
ENGINEERING
1ST YEAR
2ND YEAR
3RD YEAR
4TH YEAR
ENGG.
MECHANICS
THEORY OF
STRUCTURES
I
THEORY OF
STRUCTURES
II
STRUC.
ENGG.
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History of Structural Engineering
 Why history is important?
 One reason why history is important it
that the past has value to our society.
 History is the narrative of mankind.
 History when presented properly
lends itself to critical analysis.
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History of Structural Engineering
 Greek and Egyptian Temples
 Made of stone
 Employed beams and columns
 Many columns having little useful
space between them
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Greek temple built 2500 years ago
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Greek temples of Poseidonia (now called Paestum)
dating from the sixth century BC.
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The Temple of Debod built in early 2nd century BC
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Egypt: Temples of Karnak built 2000 years ago
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History of Structural Engineering
 Arch structures were discovered prior
to Roman era.
 Roman Empire used arches extensively
in construction.
 Stone arches had span of 100 ft and
more
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The Colosseum is one of Rome's most distinctive
landmarks. Construction of this famous amphitheatre
began in 72 AD.
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Arches
Aqueducts
Aqueduct at Segovia in eastern Spain
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The arch of Costantino built in 312 AD
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History of Structural Engineering
 From A.D. 500 to A.D.1500, structures
that were built continued to employ the
stone arch as the major structural
forms.
 Gothic Cathedrals
 Roof was supported by flying
buttresses
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Flying
Buttress
Cathedral
from North
East
Chichester
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Flying
Buttress
Cathedral
from South
East
Chichester
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History of Structural Engineering
 Fifteenth and Sixteenth centuries are known as
Renaissance.
 Galileo (1564-1642)
Concept of force and moments
Robert Hooke (1635-1703)
 Law of linear behavior of materials
Sir Isaac Newton (1642-1727)
 Laws of motion
Leonhard Euler (1707-1783)
 Buckling of columns
Palladio
 introduced the use of truss

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GALILEO
ISSAC NEWTON
ROBERT HOOKE
LEONHARD EULER
PALLADIO
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History of Structural Engineering
 Modern Era
 Introduction of Iron
 Industrial Revolution
 First major structure built or iron was Severn
River Bridge Coalbrookdale.
 Suspension bridges
 Thomas Telford’s Bridge over Menai Straits in
Wales,
 Brunel’s Clifton Bridge in Bristol,
 Finley’s Bridge over Merrimack River in
Newburyport, Massachusetts.
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Iron bridge, a cast-iron arch bridge built in 1779 across the
River Severn near Coalbrookdale, Shropshire, England
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Thomas Telford built the suspension bridge in the middle in 1826. They had
to destroy some of the castle to anchor it to the rock.
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Isambard Kingdom Brunel designs the Clifton Suspension Bridge at
Bristol. Two hundred feet above the River Avon, the bridge is 700 feet
long.
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History of Structural
Engineering
Rank
Building - City - Country
Year
Stories Height
1.
Burj Dubai, Dubai, UAE
2008
189*
850m*
2.
Taipei 101, Taipei, Taiwan
2004
101
509m
3.
Petronas Tower 1, Kuala Lumpur, Malaysia
1998
88
452m
4.
Petronas Tower 2, Kuala Lumpur, Malaysia
1998
88
452m
5.
Sears Tower, Chicago, USA
1974
110
442m
6.
Jin Mao Building, Shanghai, China
1999
88
421m
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Forms of Structures
Structural Forms
Cables
Arches
Trusses
Beams
Surfaces
Membranes
Plates
Shells
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Cables
 Cables stretch well and are light, so they are
useful in large structures. They only take tension
stresses.
 Cables can be crisscrossed and combined with
surface materials to achieve light and large
structures.
 Examples of this technique are Suncoast Dome
and Georgia Dome in the United States
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Hanger
Tower
Cable
Cable
Anchorage
Road Way
Golden Gate Bridge, San Francisco
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Cables
 Grace Memorial Bridge over the Cooper River
 Between Charleston, South Carolina (USA) and
Mount Pleasant, South Carolina, stands the Grace
Memorial Bridge.
 Completed in 1929, the cantilever steel structure has
a main span of 1050 ft., or 320 m. and a total length of
3.6 miles or 5.79 Kilometers.
 A parallel bridge, with a similar design but a shorter
main span, was built in 1966. This allowed the old
bridge to be converted to one-way traffic.
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Grace Memorial Bridge over the Cooper River
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Arches
 An arch is a curved structure capable of spanning
a space while supporting significant weight (e.g. a
doorway in a stone wall).
 The arch is significant because, in theory at least,
it provides a structure which eliminates tensile
stresses in spanning an open space.
 All the forces are resolved into compressive
stresses.
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Chinese Moon Bridge
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Made by Zhao1974 in Hebei Province, China. Built by the
architect Li Chun from 595 to 605 AD. World's oldest fully-stone,
open-spandrel, segmental arch bridge.
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Triangular Arch
Rampant Round
Arch
Round Arch
Lancet Arch
Segmental Arch
Shoulder Flat
Arch
Equilateral
Pointed Arch
Three-Foiled
Cusped Arch
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Horseshoe Arch
Inflexed Arch
Three-centered
Arch
Ogee Arch
Elliptical Arch
Reverse Ogee
Arch
Parabolic Arch
Tudor Arch
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Truss
 In architecture and structural engineering, a truss
is a structure comprising one or more triangular
units constructed with straight slender members
whose ends are connected at joints.
 A plane truss is one where all the members and
joints lie within a 2-dimensional plane, while a
space truss has members and joints extending
into 3 dimensions.
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Truss
All members are assumed in
axial compression or tension.
Members are joined with the
help of frictionless pins.
Loads are applied at joints only.
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Types of Trusses
Common Truss
Flat Truss
Truncated Truss
It is characterized
by its triangular
shape.
It gets its name
from its parallel top
and bottom chords.
A combination of
the two is a
truncated truss.
It is most often
used for roof
construction.
It is often used for
floor construction.
It is used in hip
roof construction.
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Support structure under the Auckland Harbour Bridge.
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A Vierendeel bridge; note the lack of diagonal elements in the
primary structure and the way bending loads are carried between
elements
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Beams
 A beam is a structural element that carries
load primarily in bending (flexure).
 Beams generally carry vertical gravitational
forces but can also be used to carry horizontal
loads (i.e. loads due to an earthquake or
wind).
 The loads carried by a beam are transferred to
columns, walls, or girders, which then transfer
the force to adjacent structural compression
members.
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Beams
 It requires only vertical supports at ends
generally.
 It is a compact structure.
 It’s disadvantage is that it sometimes
uses materials less economically than
other structural systems.
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Surfaces
Surfaces
Membranes
Plates
Shells
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Membranes
 Thin sheets of material
 Resist applied loads by
tension.
 Examples are tents, sails,
balloons etc
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Plates
 Plates are flat surfaces
that transfer loads by
bending in a manner
similar to beams.
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Shells
 Shell is rigid surface that
transfers loads in two
directions.
 The primary difference
between a plate and a
shell is that the shell has
curvature whereas the
plate does not.
TWA Flight Center, John F. Kennedy
International Airport, New York.
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Materials
Properties
of Material
Deformation
Characteristics
Strength
Comp.
Tension
Resist.
Strengt
h to
weight
ratio
Stiff
Elastic
Ductile
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Materials
 Aggregates
 Steel
 Concrete
 Wood
 Aluminum
 Fiber Glass
 Composite Materials etc.
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Loads
Loads
Static Loads
Loads
Dynamic
Loads
Dead
Live
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Loads
Building
Live Loads
Bridge Live
Loads
Live Loads
Earthquake
Loads
Snow
Loads
Wind
Loads
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