the ppt discusses the facts , concept and the construction details of CN Tower. it deals with the quick facts and deatails about its parts along with a timeline

1. GROUP 5
• ARUN GEORGE
• ATHULYA JOHN PAULS
• CARIS SUSAN
• MELBIN BIJU
• SHAHZAD AHMED

2. CN TOWER
THE TALLEST BUILDING IN THE
WORLD FROM 1976 TO 2007

3. INTRODUCTION
The CN Tower in downtown Toronto is
a concrete communications/observation
tower and an iconic symbol of Canada. The
tower was built by Canadian National in
response to the need for uninterrupted
communications broadcasting over the
skyline of buildings constructed during
Toronto’s 1960s boom.

4. In 1995 it was ranked as one of the
Seven Wonders of the Modern
World by the American Society of
Civil Engineers.

5. GENERAL INFORMATION
• LOCATION : 301 Front Street West
Toronto, Ontario
• CONSTRUCTION PERIOD : 1973 – 1976
• COST : $63,000,000
• ARCHITECTS : John Andrews, Webb Zerafa, Menkes
Housden
• TYPE : Observation , telecommunications,
attraction , Restaurant
• FLOOR COUNT : 147

6. QUICK FACTS
• CN TOWER IS TORONTO’S TALLEST LANDMARK
• IT IS A MAJOR TOURIST DESTINATION

7. QUICK FACTS
• THE GLASS FLOOR EXPERIENCE YOU DARE TO WALK ON
FLOOR

8. QUICK FACTS
• THE CN TOWER HEIGHT IS 553.33 METERS
• THERE ARE 360 RESTAURANTS IN CN TOWER

9. QUICK FACTS
• It has two water tanks of more than 56,000 liters each that
recharge automatically.
• It is estimated that the CN Tower weighs 134,193 tonnes

10. HISTORY
• IN THE '60s MOST THE LOW HEIGHT BUILDINGS WERE CHANGED TO
SKY SCAPERS
• THIS CAUSED SERIOUS COMMUNICATION PROBLEMS
• THE CONSTRUCTION OF CN TOWER HELPED SOLVING THESE
PROBLEMS WITH ITS MICROWAVE RECEPTORS AND ANTENNAS.
• THE PEOPLE OF TORONTO AREA NOW ENJOY
ONE OF THE CLEAREST RECEPTION IN
NORTH AMERICA

11. LOCATION
The CN Tower is located at 301 Front Street West in the heart of
the Entertainment District, on the north shore of Lake Ontario,
Toronto, Canada.
The Tower is easily accessible from Union Station and the streets
and major roads.

12. CONCEPT
• In the beginning was planned with the aim of placing an
antenna high enough to permit the transmission and
reception of signals without any interference, especially due
to the tall buildings of Toronto.
• Before completion, the architects added to it a revolving
restaurant and observation deck

13. CONSTRUCTION
• Concrete is a material that has been used for centuries
and some of the world’s most famous ancient structures,
such as the Pantheon (built 118-128 AD) and the
Coliseum in Rome (70 AD), were made from concrete.
• Known for its strength, versatility, affordability and ability
to withstand natural disasters, such as earthquakes, it is
readily used in the construction of a number of dramatic
structures worldwide including statues, bridges, dams,
buildings and tunnels.

14. BUILT USING A CLIMBING CONCRETE FRAMEWORK

15. UNIQUE ELEMENTS
• GLASS FLOOR (64mm THICK)
• LIFT ( 6 GLASS ELEVATORS )

16. UNIQUE ELEMENTS
• ANTENNA
( The transmitting antenna measures 102 meters and consists
of 44 pieces of steel with 8 tons the heaviest )

17. CONSTRUCTION MATERIALS
• CONCRETE : 40.532 CUBIC METERS
• POST TENSIONING STEEL : 129 MILES
• STEEL REINFORCEMENT : 5080 TONS
• STRUCTURAL STEEL : 600 TONS

18. DESIGN AND CONSTRUCTION
• The construction of the tower was an ambitious project that
involved 1,537 workers, employed 24-hours a day for 40
months.
• 56,000 tonnes of earth and shale was removed from the site
for foundation
• The base foundation incorporated 7,000 m3 of concrete, 450
tonnes of rebar and 36 tonnes of steel cable.

19. • Poured a thick concrete and steel foundation 6.71 m (22 ft)
deep
• The y-shaped foundation contained 7,046 cubic metres (9,200
cubic yards) of concrete, 453.5 metric tonnes (500 tons) of
reinforcing steel and 36.28 metric tonnes (40 tons) of thick,
tensioning cables.

20. Building the tower inch-by-inch
• The next mission was to build the Tower’s 335m concrete
shaft a hexagonal core with three curved support arms.
• Concrete was poured into a massive mold or “*slipform".

21. *SLIP FORM
A mould in which a concrete structure of uniform cross section
is cast by filling the mould with liquid concrete and then
continuously moving and refilling it at a sufficiently slow rate for
the emerging part to have partially set.

22. • As the concrete hardened, the slipform, supported by a ring of
climbing jacks powered by hydraulic pressure, moved
upwards, gradually decreasing in size to produce the Tower's
gracefully tapered contour.
• In order to maintain consistency, all concrete used in the
Tower had to come from the same source
• Workers mixed every ounce of the concrete on site,
continuously testing and re-testing it and then reinforcing it
with a unique system of **post-tensioning.

23. **Post Tensioning
is a technique for reinforcing concrete. Post-
tensioning tendons, which are prestressing steel
cables inside plastic ducts or sleeves, are
positioned in the forms before the concrete is
placed

25. Building a seven-storeybuildingat 1,100feet
• After the completion of the shaft they started constructing the
Skypod (a seven-storey building that would eventually house
two observation decks, 36O Revolving Restaurant, Horizons,
the GLASS FLOOR and various technical areas )
• This construction in the sky involved
lifting 318 metric tons of steel and
wood brackets up the sides of the
Tower using 45 hydraulic jacks and
miles of steel cable.

26. Construction of the
seven storey building

27. • Creating the two-storey Space Deck, the World's Highest
Public Observation Gallery, involved Cantilevering a concrete
platform around the top edge of the Tower.
• A glass wall was suspended from the overhang of its roof,
banking inwards at the bottom and completely enclosing the
upper storey.

28. • The next mission was the placing of the Antenna at the top
• This was done with the help of an helicopter Olga

29. • CN Tower engineers attached two optical plumbs specially
designed to keep tall buildings straight to permanent mounts
on the tower and suspended a 113.4 km steel cylinder from an
aviation cable in the Tower's core.

30. The construction of CN TOWER
Was completed in the year
1976

31. PHASES OF CONSTRUCTION
CONSTRUCTING THE BASE , JULY 1973

32. BRACKETS BEING RAISED ,
AUGUST 1974

33. MAIN POD CONSTRUCTION , APRIL 1975

34. HELICOPTER LIFTING PART OF
THE ANTENNA ,
APRIL 1975

35. NEARING COMPLETION ,
DECEMBER 1975

36. TWO MONTHS AFTER OPENING ,
AUGUST 1976

37. FACTS AT A GLANCE
• The CN Tower was built by the Canadian National Railway.
• Opened to the public on June 26, 1976
• Official opening on October 1, 1976
• Original cost: $63 million
• Adjusted cost (1997 dollars): $250 million
• Total construction time: 40 months
• Number of construction workers: 1,537
• Total weight of the Tower: 117,910 metric tonnes (130,000
tons)
• Volume of concrete: 40,523.8 cubic metres (53,000 cubic
yards)

38. FACTS AT A GLANCE
• Reinforcing steel: 4,535 metric tonnes (5,000 tons)
• Structural steel: 544.2 metric tonnes (600 tons)
• Number of elevators: 6 (including 2 which officially opened
March 20, 1997)
• Speed of elevators: 6 metres/second (20 feet/second)
• Slow speed of elevators (in high winds): 1.5 metres/second (5
feet/second)
• Attendance: about 1.8 million per year
• Total staff (off season): approximately 400
• Total staff (peak season): approximately 550

39. FACTS AT A GLANCE
• Maximum sway in 190 km/h winds with 320 km/h gusts (120
mph winds with 200 mph gusts):
• Antenna: 6 ft., 8 in. from centre Sky Pod: 3 ft., 4 in. from
centre Tower Sphere: 1 ft., 7 in. from centre
• Windows: Double-pane armourplated
• Thickness of windows: Outer pane - 9.5 mm (3/8 inch), inner
pane - 6.4 mm (1/4 inch)
• Capacity of 360, The Restaurant at the Tower: 400 people
• Time it takes to revolve once: 72 minutes
• Capacity of Horizons Café: 500 people
• Broadcast Facilities: UHF, VHF Television; FM Radio; Microwave
Transmissions; Fixed Mobile Systems

40. FACTS AT A GLANCE
• Broadcast Facilities: UHF, VHF Television; FM Radio; Microwave
Transmissions; Fixed Mobile Systems
• Companies that broadcast from the Tower:
• CBC Channel 5 & 25, CFMT 47, CFTO 9, City 57, Global/CIII 41,
TV Ontario 19, LOOK Communications (Digital), CHFI/Rogers,
CFNY FM, CHIN FM, CHUM FM, CILQ FM, CJEZ FM, CJRT FM,
CKFM FM, Bell Canada, Cantel, Motorola, TTC
• Thickness of The Glass Floor: 2 1/2 ". Layers, from the top
down:
• 3/16" scuff plate (replaced annually) Two 1/2" layers of clear
tempered glass, laminated together A one inch layer of air (for
insulation) Two 1/4" layers of clear tempered glass, laminated
together Size of each panel: 42" by 50" Load tests are performed
annually on each panel to ensure safety

41. THANKYOU