Introduction%20to%20TOS-I

1
Introduction to TOS-I

• Theory of Structure - I

2
Lecture Outlines

• Introduction
• History of Structural Engineering
• Forms of Structures
• Materials
• Loads

3
Introduction
STRUCTURAL ENGINEERING
1ST YEAR
2ND YEAR
3RD YEAR
4TH YEAR
ENGG. MECHANICS
THEORY OF STRUCTURES I
THEORY OF STRUCTURES II
STRUC. ENGG.
4
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.

5
History of Structural Engineering

• Greek and Egyptian Temples
• Made of stone
• Employed beams and columns
• Many columns having little useful space between
  them

6
Greek temple built 2500 years ago
7
Greek temples of Poseidonia (now called Paestum)
dating from the sixth century BC.
8
The Temple of Debod built in early 2nd century BC

9
Egypt Temples of Karnak built 2000 years ago
10
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

11
The Colosseum is one of Rome's most distinctive
landmarks.  Construction of this famous
amphitheatre began in 72 AD.
12
Arches
Aqueducts
Aqueduct at Segovia in eastern Spain
13
The arch of Costantino built in 312 AD
14
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

15
Flying Buttress
Cathedral from North East Chichester
16
Flying Buttress
Cathedral from South East Chichester
17
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

18
GALILEO
ROBERT HOOKE
ISSAC NEWTON
LEONHARD EULER
PALLADIO
19
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 Telfords Bridge over Menai Straits in
  Wales,
• Brunels Clifton Bridge in Bristol,
• Finleys Bridge over Merrimack River in
  Newburyport, Massachusetts.

20
Iron bridge, a cast-iron arch bridge built in
1779 across the River Severn near Coalbrookdale,
Shropshire, England
21
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.
22
Isambard Kingdom Brunel designs the Clifton
Suspension Bridge at Bristol. Two hundred feet
above the River Avon, the bridge is 700 feet
long.
23
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
24
(No Transcript)
25
Forms of Structures
Structural Forms
Cables
Arches
Trusses
Beams
Surfaces
Membranes
Plates
Shells
26
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

27
(No Transcript)
28
(No Transcript)
29
Tower
Hanger
Cable
Cable Anchorage
Road Way
Golden Gate Bridge, San Francisco
30
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. 

31
Grace Memorial Bridge over the Cooper River
32
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.

33
Chinese Moon Bridge
34
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.
35
Triangular Arch
Round Arch
Segmental Arch
Rampant Round Arch
Shoulder Flat Arch
Three-Foiled Cusped Arch
Lancet Arch
Equilateral Pointed Arch
36
Three-centered Arch
Elliptical Arch
Horseshoe Arch
Inflexed Arch
Ogee Arch
Reverse Ogee Arch
Tudor Arch
Parabolic Arch
37
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.

38
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.

39
Types of Trusses
Common Truss It is characterized by its
triangular shape. It is most often used for
roof construction.
Flat Truss It gets its name from its parallel
top and bottom chords. It is often used for
floor construction.
Truncated Truss A combination of the two is a
truncated truss. It is used in hip roof
construction.
40
Support structure under the Auckland Harbour
Bridge.
41
A Vierendeel bridge note the lack of diagonal
elements in the primary structure and the way
bending loads are carried between elements
42
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.

43
Beams

• It requires only vertical supports at ends
  generally.
• It is a compact structure.
• Its disadvantage is that it sometimes uses
  materials less economically than other structural
  systems.

44
(No Transcript)
45
(No Transcript)
46
Surfaces
Surfaces
Membranes
Shells
Plates
47
Membranes

• Thin sheets of material
• Resist applied loads by tension.
• Examples are tents, sails, balloons etc

48
Plates

• Plates are flat surfaces that transfer loads by
  bending in a manner similar to beams.

49
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.
50
Materials
Properties of Material
Strength
Deformation Characteristics
Comp. Tension Resist.
Strength to weight ratio
Stiff
Elastic
Ductile
51
Materials

• Aggregates
• Steel
• Concrete
• Wood
• Aluminum
• Fiber Glass
• Composite Materials etc.

52
Loads
Loads
Loads
Static Loads
Dynamic Loads
Dead
Live
53
Loads
Building Live Loads
Bridge Live Loads
Live Loads
Earthquake Loads
Snow Loads
Wind Loads
54
Thank You