Upload
melbin-biju
View
136
Download
3
Embed Size (px)
Citation preview
GROUP 5
• ARUN GEORGE• ATHULYA JOHN PAULS• CARIS SUSAN• MELBIN BIJU• SHAHZAD AHMED
CN TOWER
THE TALLEST BUILDING IN THE WORLD FROM 1976 TO 2007
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.
In 1995 it was ranked as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers.
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
QUICK FACTS• CN TOWER IS TORONTO’S TALLEST LANDMARK
• IT IS A MAJOR TOURIST DESTINATION
QUICK FACTS• THE GLASS FLOOR EXPERIENCE YOU DARE TO WALK ON FLOOR
QUICK FACTS• THE CN TOWER HEIGHT IS 553.33 METERS• THERE ARE 360 RESTAURANTS IN CN TOWER
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
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
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.
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
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.
BUILT USING A CLIMBING CONCRETE FRAMEWORK
UNIQUE ELEMENTS• GLASS FLOOR (64mm THICK)
• LIFT ( 6 GLASS ELEVATORS )
UNIQUE ELEMENTS• ANTENNA ( The transmitting antenna measures 102 meters and consists of 44 pieces of steel with 8 tons the heaviest )
CONSTRUCTION MATERIALS
• CONCRETE : 40.532 CUBIC METERS
• POST TENSIONING STEEL : 129 MILES
• STEEL REINFORCEMENT : 5080 TONS
• STRUCTURAL STEEL : 600 TONS
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.
• 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.
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".
*SLIP FORMA 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.
• 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.
**Post Tensioningis 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
Building a seven-storey building at 1,100 feet
• 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.
Construction of the seven storey building
• 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.
• The next mission was the placing of the Antenna at the top
• This was done with the help of an helicopter Olga
• 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.
The construction of CN TOWERWas completed in the year1976
PHASES OF CONSTRUCTION
CONSTRUCTING THE BASE , JULY 1973
BRACKETS BEING RAISED ,AUGUST 1974
MAIN POD CONSTRUCTION , APRIL 1975
HELICOPTER LIFTING PART OF THE ANTENNA , APRIL 1975
NEARING COMPLETION ,DECEMBER 1975
TWO MONTHS AFTER OPENING ,AUGUST 1976
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)
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
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
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
THANK YOU