The One And Only CN Tower

The one and only tallest standing structure North America. You glass elevator p. The one and only incredible there glass floor, which y scary . There revolving restaurant which offers spectacular views y.

The one and only CN Tower, located downtown Toronto, Ontario, Canada, communications tourist tower standing 553.33 metres (1,815.39 ) . It surpassed height Ostankino Tower while still under construction 1975, becoming tallest -standing structure globe. on September 12, 2007, after holding record 31 years, CN tower surpassed height y still-under-construction Burj Dubai. It remains tallest -standing structure Americas signature Toronto's skyline, attracting million international visitors annually.

CN originally referred Canadian National, the railway company built tower. Following railway's decision divest - freight railway assets, prior company's privatization 1995 transferred tower Canada Lands Company, federal Crown corporation responsible estate development. Since local residents wished retain CN Tower, abbreviation expand Canada's National Tower rather original Canadian National Tower; however, neither these commonly .

In 1995, CN Tower declared modern Seven Wonders World y American Society Civil Engineers. It belongs World Federation Great Towers.

The one and only concept CN Tower originated 1968 Canadian National Railway desire build large TV radio communication platform serve Toronto area, demonstrate strength Canadian industry CN particular. These plans evolved x years, project became official 1972. The one and only tower would p Metro Centre ( CityPlace), large development south Front Street Railway Lands, large railway switching y being redundant y newer yards outside y. Key project members NCK Engineering structural engineer; John Andrews Architects; Webb, Zerafa, Menkes, Housden Architects; Foundation Building Construction; Canron (Eastern Structural Division).

At time, Toronto town, 1960s early 1970s construction numerous large skyscrapers downtown . This broadcasting downtown y difficult reflections buildings. The one and only y solution would raise antennas above buildings, demanding tower 300 metres (984 ) tall. Additionally, time, communications place point--point microwave links, whose antennae covered roofs large buildings. As every skyscraper added downtown, former --sight links longer possible. CN intended "hub" space microwave links, visible almost y building Toronto . The one and only CN Tower least y Gamble Street Richmond Hill, Ontario, approximately 30 kilometres (19 ) north, several points south shore Lake Ontario, 48 kilometres (30 ) south.

The one and only original p tower envisioned tripod consisting three independent cylindrical "pillars" linked various heights y structural bridges. Had built, design would considerably shorter, metal antenna located roughly where concrete section between main level Sky Pod today. As design effort continued, evolved current design single continuous hexagonal Sky Pod, three support g blended hexagon below level, forming large Y-shape structure ground level.

The one and only level current evolved around time, Sky Pod p plans until later. one engineer particular visitors would higher observation would worth paying extra , costs terms construction prohibitive. It around point realized tower could become globe's tallest structure, plans changed incorporate subtle modifications throughout structure .

Construction CN Tower began February 6, 1973 massive excavations tower foundation. By foundation complete, 56,000 tonnes (61,729 short ) shale rerelocated depth 15 metres (49.2 ) centre, incorporating 7,000 cubic metres (9,156 y) concrete 450 tonnes (496 short ) rebar and 36 tonnes (40 short ) steel cable built thickness 6.7 metres (22 ). This portion construction fairly rapid, y months needed between start foundation being ready construction p.

To build support pillar, hydraulically-raised slipform built . This fairly impressive engineering , consisting large metal platform raised itself jacks about 6 metres (19.7 ) p y concrete below . Concrete poured continuously y 1,532 people until February 22, 1974, during which already become tallest structure Canada, surpassing recently built Inco Superstack, which built using similar methods. In total, tower contains 40,500 cubic metres (52,972 y) concrete, which mixed - order ensure batch consistency. Through pour, vertical accuracy tower maintained y comparing p form's location massive plumb- hanging , observed y small telescopes ground. Over height tower, varies vertical accuracy y y 29 millimetres (1.1 ).

In August 1974, construction level commenced. Using 45 hydraulic jacks attached cables strung temporary steel crown anchored p tower, twelve giant steel wooden bracket forms slowly raised, ultimately taking about crawl p their final position. These forms to create brackets support level, construction level itself. The one and only Sky Pod built concrete poured wooden frame attached rebar lower level deck, reinforced large steel compression around outside.

The one and only antenna originally to raised y crane well, during construction Sikorsky S-64 Skycrane helicopter became available United States Army theirs civilian operators. The one and only helicopter, named "Olga", first remove crane, antenna p 36 sections. The one and only flights antenna pieces minor tourist attraction their , schedule printed local newspapers. Use helicopter saved months construction time, with phase taking y three weeks instead planned x months. The one and only tower topped April 2, 1975 after 26 months construction, officially capturing height record Moscow's Ostankino Tower, bringing total 118,000 tonnes (130,073 ).

Two years construction, plans Metro Centre scrapped, leaving tower isolated Railway Lands a largely abandoned light-industrial space. This caused serious problems tourists access tower. Ned Baldwin, project architect John Andrews, wrote "All logic which dictated design lower accommodation upset," "Under ludicrous circumstances Canadian National would hardly chosen location build."