Presented By: G.D.R.Jayathunga T.Chailagoaban

Transcription

1 Presented By: G.D.R.Jayathunga T.Chailagoaban

2 Seven Wonders of the Modern World The 20th century has provided spectacular advances in design, engineering and construction which have allowed humanity to create an array of monumental structures. As a tribute to the greatest civil engineering achievements of the 20th century, the American Society of Civil Engineers (ASCE), with help from experts around the world has chosen the Seven Wonders of the Modern World. The international wonders demonstrate modern society's ability to achieve unachievable feats reach unreachable heights and scorn the notion "it can't be done."

3 Seven Wonders of the Modern World These wonders were judged on factors such as pioneering of design and construction, contributions to humanity, and engineering challenges that were overcome. Man has an incredible ability to make the impossible, possible. "The original wonders were amazing sites to behold, but today's modern wonders are more than simply awe inspiring. They are functional, operational masterpieces that have revolutionized civil engineering and benefited humanity. The Seven Wonders of the Modern World are a tribute to universal human desire to triumph over the impossible" added Charles A. Parthum, President, ASCE 1996.

4 Seven Wonders of the Modern World ASCE honored the following civil engineering marvels as seven wonders of the modern world: Empire State Building (New York) Itaipu Dam (Brazil/Paraguay) CN Tower (Toronto) Panama Canal (Panama) Channel Tunnel (England & France) North Sea Protection Works (Netherlands) Golden Gate Bridge (San Francisco) The list evokes the storied seven wonders of the ancient world, which first illustrated humanity's fascination with engineering works that seemingly defied the limits of nature

5 Seven Wonders of the Modern World Empire State Building (New York) Itaipu Dam (Brazil/Paraguay) CN Tower (Toronto) Panama Canal Channel Tunnel North Sea Protection Works (Panama) (England & France) (Netherlands) Golden Gate Bridge (San Francisco)

6 LOCATIONS OF THE WONDERS Delta Works Channel Tunnel CN tower Empire State Golden Gate Bridge Panama Canal Itapu Dam

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8 Empire State Building The Empire State Building is a 102-story contemporary Art Deco style skyscraper in New York City, declared by the American Society of Civil Engineers to be one of the Seven Wonders of the Modern World. HISTORY Construction of the Empire State Building began in March of 1930 on the site of the old Waldorf- Astoria Hotel at 350 Fifth Avenue at 34th Street. It was completed 14 months later in May, Designed by the architectural firm of Shreve, Lamb, & Harmon Associates. The tower takes its name from the nickname of New York State. The Empire State Building, at 102 stories, was the tallest building in the world until the completion of the first tower of the World Trade Center in Lower Manhattan in The building belongs to the World Federation of Great Towers The Empire State Building soars into the sky. Since the World Trade Center was destroyed in the September 11, 2001 attacks, it was again the tallest building in New York City. It is currently the second tallest building in the United States after the Sears Tower in Chicago.

9 Empire State Building Architects: Shreve, Lamb & Harmon Associates Builders: Starrett Brothers & Eken, Inc. Height: 1,472 feet (448 meters) to top of antennae. 1,250 feet (391 meters) to 102nd floor observatory. 1,050 feet (320 meters) to 86th floor observatory. Volume: 37 million cubic feet. Weight of building: approximately 330,000 metric tonnes. Total floor area: 2,200,000 square feet (200,000 square metres). Area of Site: 83,860 square feet. Construction schedule: Excavation: Begun January 22, 1930, before demolition of old Waldorf-Astoria Hotel completed. Construction: Begun March 17, Framework rose at the rate of 4.5 stories per week. Cornerstone: Laid by Alfred E. Smith, former governor of New York, September 17, Total time: 7 million man hours, 1 year and 45 days work, including Sundays and holidays.

10 Empire State Building Work Force: 3,400 during peak periods, 14 of the workers died during construction. Masonry: completed on November 13, 1930.(masons finished the exterior in eight months) Plumbing: installed 51 miles of pipe. Telephones: installed 17 million ft. of wires. Ironwork: riveted 58,000-ton frame together in 23 weeks Building Materials: Exterior: Indiana limestone and granite, trimmed with aluminum and chrome-nickel steel from the 6th floor to the top. Interior lobby: Ceiling high marble, imported from France, Italy, Belgium and Germany. Cost including land: $40,948,900. (451,173,508 in today's money) Cost of building alone: $24,718,000 (272,342,000 in today's money) It was the first building to have more than 100 floors. It has 6,500 windows, 73 elevators and 1,860 steps to the top floor. The Empire State Building was officially opened on May 1, 1931, by President Herbert Hoover who pressed a button in Washington, D.C. to turn on the building's lights.

11 Empire State Building Empire State Building remained the tallest skyscraper in the world for a record 41 years until the construction of the World Trade Center The building is typically described as being 102 stories tall, but it has only 85 stories of commercial and office space (2,158,000 square feet), with an observation deck on the 86th floor. The remaining 16 stories represent the spire, which supports the antenna on top. Unlike most of today's high-rise buildings, the Empire State has a classic façade. The building's most astonishing feat however, was the speed in which it rose into the New York City skyline, within only one year and 45 days. From its opening until the 1940s much of its office space went un rented. This lack of inhabitants earned it the nickname "Empty State Building" in its early years. More than thirty people have committed suicide from atop the building. The fence around the observatory terrace was put up in 1947 after five people tried to jump over a three-week span. Floodlights illuminate the top of the building at night, in colors chosen to match seasonal and other events, such as Christmas. New York City is the largest media market in the United States, and nearly all of New York's commercial broadcast stations (both television and radio) have transmitted from the top of Empire. The building was so well-engineered that is was easily repaired after a bomber crashed into it in 1945

12 Empire State Building The Empire State Building, a strong symbol of New York. The lean, perpendicular Empire State Building among the smaller Manhattan buildings The Empire State Building is the centerpiece of Manhattan. The Empire State Building eclipses the ground below. An aerial view of the Tower. The Tower of the Empire State Building, the tallest point in the city. The Lobby greets visitors with its classic 1930 Art Deco style. The lightning rod on the Tower is struck more than 100 times per year.

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14 Itaipu Dam History The Itaipu Hydroelectric Power Plant is the result of heavy negotiations between the two countries Brazil and Paraguay during the 1960s. The first step of the initiation was on July 22, 1966 when the Ministers of Foreign Affairs of Brazil (Juracy Magalhães) and Paraguay (Sapena Pastor) signed a joint statement known as the "Act of Ygazu". By this joint declaration, a study and evaluation of the hydraulic resources of the the seventh biggest river of the world, Parana River (owned jointly by Brazil and Paraguay) followed. On April, 26, 1973, the two governments of the states signed a treaty "for the development of the hydroelectric resources of the Parana River" and founded "ITAIPU Binacional" (a cooperation with the legal, administrative and financial capacities and technical responsibility to plan, set up and operate the plant) in May, 17, 1974 The world's largest hydroelectric project upon its completion in Total view of the ITAIPU power plant Itaipú is one of the Seven Wonders of the Modern World, according to a worldwide survey conducted by the American Society of civil Engineers (ASCE) and published in Dec as a cover article of the North- American "Popular Mechanics".

15 Itaipu Dam Located at the Brazilian-Paraguayan border, 14 kilometers North of the International Bridge linking the cities of Foz do Iguaçú, Brazil, and Ciudad del Este, Paraguay, and not far from the Argentinean border. The Itaipú hydroelectric power plant is the largest development of its kind in operation in the world. Built from 1975 to 1991, in a binational development on the Paraná River, Itaipú represents the efforts and accomplishments of two neighboring countries, Brazil and Paraguay The construction work started in 1975, reaching its peak in 1978 with people at work.on October 14, 1978, the Parana River had its route changed, which allowed a section of the riverbed to dry so the dam could be built.. During its construction, workers shifted the course of the seventh largest river in the world by removing 50 million tons of earth and rock to dig a 1.3-mile bypass. Monthly on-site concrete production reached m³. The height of the dam reaches 196 m & it stretches to a length of 7.76 km. The main dam, as high as a 65-story building, is composed of hollow concrete segments, while the flanking wings are earth and rock fill. The lake created by this is 170 km long and contains 29 billion tons of water The volumes of construction in Itaipú are also impressive. The volume of iron and steel utilized in the Dam structure would be enough to build 380 Eiffel Towers, and the volume of concrete used in Itaipú represents 15 times the volume utilized to build the Channel Tunnel between France and England.

16 Itaipu Dam The plant's reservoir began its formation on October , when the dam works were completed and the side canal's gates were closed. The Powerhouse is located at the toe of the main Dam, most of it on the river bed and the rest on the Diversion Channel. The nominal power of the plant is 12,600 MW, divided between 18 generating units of 700 MW each, 15 of which are located in the main Powerhouse and the remaining three on the Diversion Channel Some 160 tons of water per second pour onto each turbine, generating 12,600 mega watts and a reliable output of 75 million MWh a year. Unit 1 started to operate in December Electrical grid connection to Paraguay was established in March 1984, Brazil was connected 5 months later. In March 1991 the last unit (No.18) was put into operation. The water intake of one single 715 MW Francis-turbine is 700 m³/s, its weighted efficiency is 93.8%. Each year ITAIPU generates 75 TWh of electricity and avoids 67.5 million tons of carbondioxide emissions - compared to coal power plants. The final cost of ITAIPU amounts to US$ 20 billion,

17 Itaipu Dam The lake created by ITAPU dam Its area reaches km 2, its length 170 km and its average width 7 km. On top of the 7.6 km dam A m³ of concrete was used for the project ITAIPU At the bottom of the 196 m tall dam The white tubes are containing the inlets for the 18 tubines (715 MW each). Inside the ITAIPU Powerhouse Dimensions: length: 986 m, maximum height: 112 m and width: 99m. The red line on the floor indicates the border of Brazil and Paraguay.

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19 CN Tower History: Toronto was a "boom town" and the late 1960s and early 1970s had seen the construction of numerous large skyscrapers in the downtown core. This made broadcasting into the downtown area very difficult due to reflections off the buildings. The only solution would be to raise the antennas above the buildings, demanding a tower over 1,000 ft (305 m) tall. Additionally, at that time most data communications took place over point-to-point microwave links, whose dish antennas used to cover the roofs of large buildings. As each new skyscraper was added to the downtown, former line-of-sight links were no longer possible. The concept of the CN Tower originated in 1968 by Canadian National Railways (CN) to build a large TV and radio communication platform above Toronto's tallest buildings to serve the Greater Toronto Area, as well as demonstrating the strength of Canadian industry, and CN in particular. In 1995, the CN Tower was declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers. It also belongs to the World Federation of Great Towers. The CN Tower in Toronto, Ontario, stands at m (1,815 ft), and is the world's tallest freestanding structure (the tallest self-supporting man-made structure) for more than 30 years since The CN Tower head architect was Adam Vinter.

20 CN Tower The CN Tower consists of several substructures. The main portion of the Tower consists of a hollow concrete pillar containing the elevators, stairwells and power and plumbing connections. On top is the 102 m metal broadcast antenna, carrying TV and radio signals. There are two main visitor areas, the main seven-story Sky pod located at the 330 m level, and the Space deck at 447 m, just below the antenna. The Sky Pod, situated high above the main observation floor, is the highest public observation deck in the world. From its top, it is possible on a clear day to see approximately km away. At 342 m is the Glass Floor and Outdoor Observation Deck. The Glass Floor is 256 sq ft and can withstand a pressure of 4,100 kpa (600 lbs/sq in). Some people experience vertigo (head rush) by walking out on the glass floor and looking down at the ground below. At 346 m is the Horizons Cafe and the Lookout Level, and at 351 m is the 360 Restaurant, which completes a full revolution once every 72 minutes. The microwave receivers for distant signals are housed at 338 m (1,109 ft), and the top of the transmission antenna is at the apex of the tower. A metal staircase with 1,776 steps to the Lookout level, reaching 2,579 steps by the Sky Pod, and is the tallest metal staircase on earth. intended for emergency use and are not open to the public. Approximately 30 minutes to climb to the base of the radome (the white ring around the bottom of the main pod).

21 CN Tower Construction on the CN Tower started on February 6, 1973 with massive excavations at the tower base for the foundation. By the time the foundation was complete, 62,000 tons of earth and shale were removed to a depth of 15 m in the center. a base incorporating 7,034 m³ of concrete with 500 tons of steel re-bar and 40 tons of steel cable to a thickness of 6.7 m. Only four months were needed for the foundation being ready for construction on top. To build the main support pillar, a hydraulically-raised slip form was built at the base.[a large metal platform that raised itself on jacks at about 6 m per day as the concrete below set.] Concrete was poured continuously by a team of 1,537 people until February 22, 1974, to become the tallest structure in Canada In August of the same year(1974), construction of the Sky Pod commenced. The Sky Pod is a seven-story structure housing two observation decks, a revolving restaurant, a nightclub, and broadcasting equipment. The Space Deck was built of concrete poured into a wooden frame reinforced with a large steel compression band around the outside.

22 CN Tower The tower contains 40,524 m³ of concrete In total, all of which was mixed on-site in order to ensure batch consistency. The Sky Pod is reached by six high-speed, glass-fronted elevators whose rapid rise simulates a jetliner's takeoff, unless weather conditions call for a much slower ascent. The concrete tower continues above the Sky Pod, ending at the Space Deck 1,465 feet up. The Space Deck receives support from cantilevers extending out of the concrete section beneath it. After a 58-second elevator ride from the SkyPod below, visitors can enjoy breathtaking vistas from a glass-enclosed balcony enabling to glimpse sites 75 miles away on a clear day. The 335-ft communications mast was entirely covered by a fiberglass-reinforced sheathing to prevent icing. The constant surveillance kept the structure an incredible 1.1 inches within plumb. Engineers established a wind-tolerance standard for the tower of 260 miles an hour, a level well above nature's most extreme demands. Because the tower is an easy target for lightning, copper grounding wires were installed. As a result, visitors can safely view some 75 spectacular strikes a year. The tower was topped off on April 2, 1975 after 40 months of construction bringing the total mass to 117,910 metric tonnes (a weight of 130,000 tons). The CN Tower opened to the public on June 26, 1976, although the official opening date was October 1st. The construction cost was approximately U$57 million (in 1975). Almost twice as tall as the Eiffel Tower and more than three times the height of the Washington Monument, the CN Tower has taken proud ownership of Toronto's skyline, while exorcising the ghosts from its TV sets.

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24 Channel Tunnel (Chunnel) Is a 31 mile (50.5 km)-long rail tunnel beneath the English tunnel at the Straits of Dover connecting Folkstone, Kent in England to Coquelles near Calais in northern France. was finally completed in 1994 The Second longest rail tunnel in the world It is the longest undersea tunnel in the world having a 39Km section under the sea The total project cost was $21 Billion making it the most costly project of its time

25 HISTORY Channel Tunnel Idea for a tunnel was proposed when the Amiens Academy held a competition to find a new means of crossing the Channel Geology study carried out First serious attempt to build but abandoned due to political issues 1914 & The Tunnel would have shortened the world wars 1974 & Second and Third attempts Opened for pubilc

26 Channel Tunnel Some Early Thoughts

27 Channel Tunnel Construction Digging the tunnel, took 15,000 workers over seven years, with tunneling operations conducted simultaneously from both ends. 11 TBM s were used for the digging five French and six English. When TBMs met each other French one was dismanteled while the English one was buried and abanodoned In the end, almost 5 million cubic yards (4 million m³) of chalk were excavated on the British side. When both ends met the difference in the centerlines of the two ends of the tunnel was surveyed as just 358mm (14.1 inches) horizontally and 58mm (2.3 inches). The service tunnel started on 1st December 1987 and broke through in December The northern rail tunnel broke through on the 22nd May 1991 and the southern tunnel on the 28th June A TBM

28 Channel Tunnel Important Construction Facts 18 design studies were performed and the design was such that for a lifetime of 120 years. Channel tunnel comprises of 3 tunnels two running tunnel and a smaller service tunnel Between the two terminals at Folkestone and Coquelles, near Calais, the tunnels are 51 Km in length, of which 37.5 Km is undersea The two main tunnels are 30m apart The two Running Tunnels each carry a single track railway and these are connected to the Service Tunnel by Cross Passages every 375m

29 Channel Tunnel Important Construction Facts Two caverns were excavated undersea to allow trains to change tunnels if required. These are known as the English and French Crossovers. The tunnel system is kept dry by five pumping stations and sumps, three built under the sea and one on each shore. Chilled water is pumped through cooling pipes so that the tunnel air is maintained at a comfortable temperature. The tunnel is 40m beneath the sea bed

30 Operation Channel Tunnel Eurostar high speed passanger trains. The travel time between London and Paris takes just 2Hours and 15 minutes where only 20 minutes will be inside the tunnel. Eurotunnel shuttle to carry cars, coaches and wagons Eurotunnel freight shuttle trains. These carry lorries on open rail wagons, with the lorry drivers traveling in a separate passenger coach. Freight trains. These trains carry conventional rail freight or container loads between Europe and Great Britain

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32 History Panama Canal The Idea of building a canal between Atlantic and Pacific ocean starts in the year of 1534 which was stipulated by Charles V, the Emperor of Spain In 1878 Ferdinand de Lesseps, the French engineer who built the Suez Canal, began to dig a canal across the Isthmus of Panama,to build a sea level cananl Tropical disease and engineering problems halted construction on the canal in 1893, but a French business (the New Panama Canal Company) still held the rights to the project. U.S helped Panama to get Independence from Columbia and then bought the ownership of the canal project Diseases like Malayria and Yellow fever found and eliminated by the U.S doctors U.S took over the project and started the work in 1904 under the orders of the then president Theodore Roosevelt The canal opened on August 15, 1914

33 3.2Km 1.9 Km 24.2 Km 9.5 m lift 1.4 Km 16.5 m lift 1.7 Km 13.2 Km

34 Panama Canal Operation From the beginning of the buoyed entrance channel in the Gulf of Panama, ships travel 13.2 Km (8.2 mi) up the channel to the Miraflores locks, passing under the Bridge of Americas. The two-stage Miraflores lock system, including the approach wall, is 1.7 km (1.1 mi) long, with a total lift of 16.5 meters (54 ft) at mid-tide The artificial Miraflores Lake is the next stage, 1.7 km (1.0 mi) long, and 16.5 metres (54 ft) above sea level The single-stage Pedro Miguel lock, which is 1.4 km (0.8 mi) long, is the last part of the ascent with a lift of 9.5 metres (31 ft) up to the main level of the canal The Gaillard (Culbera) cut slices 12.6 km (7.8 mi) through the continental divide at an altitude of 26 metres (85 ft), and passes under the Centinnial Bridge. The Chagers River (Río Chagres), a natural waterway enhanced by the damming of Lake Gatún, runs west about 8.5 km (5.3 mi), merging into Lake Gatun Gatun Lake, an artificial lake formed by the building of the Gatun Dam, carries vessels 24.2 km (15.0 mi) across the isthmus The Gatún locks, a three-stage flight of locks 1.9 km (1.2 mi) long, drop ships back down to sea level A 3.2 km (2.0 mi) channel forms the approach to the locks from the Atlantic side Limón Bay (Bahía Limón), a huge natural harbour, provides an anchorage for some ships awaiting transit, and runs 8.7 km (5.4 mi) to the outer breakwater

35 Panama Canal Panama Canal Cross section

36 Panama Canal Operation of the Locks

37 Lock Gates under construction Water poring into the locks These gates are made of steel having air trapped in between. Thus these gates can float in the water. A motor which has output lower than a motor bike engine operates these gates.

38 Panama Canal Interesting Facts A ship traveling from New York to San Francisco can save 7'872 miles using the Panama Canal instead of going around South America From the Atlantic Ocean the Panama Canal runs south for ten miles (17 km) and then eastward to the Pacific Ocean. When the French abandoned the project they had spent over twenty years and $260,000,000. Gatun Lake, the highest part of the canal, is about 85 feet (26 meters) above sea level. The total soil excavated from the canal would build a pyramid 4,200 feet (1,280 meters) high. In the fiscal year 1994 there where 14'029 transits, which carried million long tons of cargo and paid US $ million in tolls The average time spent in transit from port to port is approx hours

39 Gatun Locks Gatun Lake Gaillard cut Miraflores Locks Pedro Miguel Locks

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41 History North Sea Protection Works Netherlands which is under the sea level was protected by the dikes and seawalls from the flooding and storms. The estuaries of the rivers Rhine, Meuse and Scheldt have been subject to many flooding over the centuries 1953 North sea flood devastated Netherlands by killing 2000 people evacuating 70,000 and destroying 4500 buildings. The Dutch government started an ambitious project to safeguard the coastline in 1953 which consisted dams, sluices, locks, dikes and storm surge barriers The project ended in 1997 with the construction of the Maeslandtkering and the Hartelkering dams. This is considered to be the world s largest flood protection project and the most extensive engineering project ever. The project reduced the costline of Netherlands to 700Km thus reucing the threat of North sea

42 North Sea Protection Works Construction The construction consisted of number of civil structures.. With over 10,250 miles of dikes (1,500 miles designated as primary dikes and 8,750 miles as secondary dikes) and 300 structures Some important structures are listed below in the chronological order Brielsegatdam (1950) Stormvloedkering Hollandse IJssel (1958) Zandkreekdam (1960) Veersegatdam (1961) Grevelingendam (1965) Volkerakdam (1969) Haringvliet sluices (1971) Brouwersdam (1971) Markiezaatskade (1983) Eastern Scheldt storm surge barrier (1986) Oesterdam (1987) Philipsdam (1987) Bathse Spuisluis (1987) Hartelkering (1997) Maeslantkering (1997)

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44 North Sea Protection Works - Maeslantkering This surge barrier was built in between This structure consists two arms of 22m high and 210m long. These are welded with 237m ling trusses to the main connecting point. The main connecting point acts like as a ball and socket joint, such as in the human shoulder or hip. The construction of the barrier cost 450 million Euro The barrier is connected to a self-operating computer system which is linked to weather and sea level data. Under normal weather conditions the two doors themselves are well protected in their dry docks and a 360 meter wide gap in the waterway gives ships enough space to pass without any inconvenience. But when a storm surge of 3.00 meter above normal sea level is anticipated in Rotterdam, the barrier will be closed automatically. Four hours before the actual closing procedure will begin, in and out going ships are warned

45 North Sea Protection Works Significance of Delta works The agricultural freshwater supply was improved. Because the border between freshwater and saltwater was moved further west, less freshwater was required to balance the freshwater-saltwater division. The excess water could be transported to the north of the Netherlands, in the direction of the Ijsselmeer (Ijssel lake), where extra freshwater was welcomed to improve the water conditions. The complete water balance of the Delta area was improved. The construction of the major and auxiliary dams, the streams in this area were able to be manipulated more easily. The construction of the Deltaworks encouraged traffic between the many islands and peninsulas. Large parts of the province of Zeeland had literally been isolated for centuries The inland waterways shipping was supported by the Deltaworks Deltaworks have influenced new developments in the areas of nature and recreation. Understandably, a number of nature reserves were irreparably damaged, but as compensation, new nature reserves have emerged at different sites.

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47 History Golden Gate Bridge The crossing of the Golden Gate Strait was for many years accomplished by a ferry running between the Hyde Street Pier at the foot of Van Ness Avenue in San Francisco and Sausalito in Marin County. The bridge was the brainchild of Joseph Strauss, an engineer responsible for over 400 drawbridges The construction started on 1921 and ended in April 1937 and opened for pedestrians on May 27.The next day President Roosevelt inaugurated the vehicle traffic Since its completion, the bridge has closed due to windy conditions five times; 1951, 1982, 1983, 1996, and The 1982 event in particular was severe enough to set the bridge in visible motion. The bridge connects Northern San Francisco Peninsula with the Southern Marin county

48 Golden Gate Bridge - Engineering aspects The center span was the longest among suspension bridges until The Golden Gate Bridge also had the world's tallest suspension towers at the time of construction, and retained that record until more recently. The bridge has six total lanes of vehicle traffic, and walkways on both sides of the bridge Total length of Bridge including approaches: 2,737 m Length of suspension span including main span and side spans:1,966 m Width of Bridge: 27 m Clearance above mean higher high water: 67 m Total weight of each anchorage: 60,000 tons Original combined weight of Bridge, anchorages, and approaches: 894,500 tons Height of tower above water: 227 m The Bridge has two main cables which pass over the tops of the two main towers and are secured at either end in giant anchorages. The main cables rest on top of the towers in huge steel castings called saddles. Diameter of one main cable with wrapping: 36 3/8 in. =.92 m Length of one main cable: 2,332 m Total length of wire used in both main cables: 129,000 km Weight of both Main Cables, Suspender Cables & Accessories: 24,500 tons Live load capacity per lineal foot: 1,814.4 kg

49 Golden Gate Bridge - Interesting Facts The color of the bridge is an orange vermilion called International orange. The color was selected because it blends well with the natural surroundings yet enhances the bridge's visibility in fog A unique aspect of the bridge's construction was the safety net set up beneath it, significantly reducing the expected number of deaths for such a project. 11 men were killed from falls during construction, and approximately 19 men were saved by the safety net. The Golden Gate Bridge is a notorious site for suicide. The official suicide count ended in 1995 when the number approached 1,000. In the eight years preceding 2003, there was an average of one suicide jump every two weeks, which brought the unofficial total to over 1,300 suicides The 220 foot (67 m) fall from the bridge takes four seconds and jumpers hit the water at 75 miles per hour (120 km/h). only 26 people are known to have survived the jump The bridge has appeared in many Hollywood movies and a theme for many fictions and cartoons.

50 Bridge in Fog Bridge in a cartoon Main tower

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