Golden Gate Bridge – San Francisco, U.S.A
Superlatives flow when describing this world-famous landmark. It is the third-largest single-span bridge ever built, and, when it was erected, it was the longest and tallest suspension structure. Named after the part of San Francisco Bay dubbed “Golden Gate” in the mid-19th century, the bridge opened in 1937. There are breathtaking views of the bay from this spectacular structure, which has six lanes for vehicles as well as a pathway for pedestrians and cyclists.
BUILDING THE BRIDGE
The Golden Gate Bridge is a classic suspension bridge of the kind first built in the mid-19th century. Its main elements are anchorages, towers (pylons), cables, and road. Enormous concrete anchorages were poured at either end to hold the cables. The steel for the towers was fabricated in Pennsylvania and shipped through the Panama Canal. Engineer Joseph B. Strauss chose John A. Roebling and Sons, builders of the Brooklyn Bridge, to make the cables. Since no derrick of the time could lift cables as heavy as these, they were spun in place, the machines passing back and forth continuously for six months. For the bridge’s paint color, architect Irving Morrow rejected the standard gray, choosing instead “International Orange,” which he felt blended better with the bridge’s setting.
The Golden Gate Bridge opened to pedestrian traffic on May 27, 1937, on schedule and under budget. On a typically foggy and windy day, over 18,000 people took part in the grand opening by walking its total length (including the approaches) of 8,981 ft (2,737 m). The next day, President Franklin D. Roosevelt pressed a telegraph key in the White House that opened the bridge to vehicular traffic. Every siren and church bell in San Francisco and Marin County sounded simultaneously. A week-long celebration followed the event.
The idea of building a bridge across the Golden Gate was conceived as early as 1872, by railroad tycoon Charles Crocker, but it was not considered feasible until architect Joseph B. Strauss stepped forward with a plan in 1921. Nine years of bureaucratic wrangling passed before Strauss was named chief engineer, but it is actually assistant chief engineer Clifford Paine, and architect Irving F. Morrow, who deserve the credit for the design and building of the bridge that stands today. By all accounts, Strauss seems to have been a difficult man; he fired his first assistant chief engineer, Charles Ellis, for attracting too much publicity. Strauss even kept Ellis’s name from appearing on any official documents.
The foundations of the twin towers are a remarkable feat of engineering. Th e south pier, 1, 125 ft (345m) offshore, was sunk 100ft (30m) below the surface in open water.
Building the Roadway
The steel-supported concrete highway was constructed from the towers in both directions. so that its weight on the cables was evenly distributed.
Sodium vapor lamps were installed to provide nonglare lighting for drivers.
The hollow, twin steel towers that support the bridge’s suspension cables rise to a height of 746ft (227m) above the water. Each tower weigh s 44,000 tons.
Man with a Plan
Chicago engineering titan Joseph Strauss is officially credited as the bridge’s designer. He was assisted by Leon Moisseiff, Charles Ellis. And Clifford Paine. Irving F. Morrow acted as consulting architect.
THE FERRIES’ RETURN
Although the bridge was built to relieve ferry congestion in San Francisco Bay, in recent years it has become so busy that thousands of car drivers have abandoned their vehicles for reliable water travel – there are now 18 ferries serving the area.
THE BRIDGE IN FIGURES
Every day, around 118,000 vehicles cross the bridge; this means that every year more than 40 million vehicles use it.
The original coat of orange paint lasted tor 27 years, with occasional touch-ups . In 1965, the paint was removed and a more durable coating was applied. Today, this is touched up by a crew of 38 painters.
The two great 7,650-tt (2,332-m) cables are more than 3 ft (1 m) thick, and contain 80,000 miles (128,744 km) of steel wire-enough to circle the Earth at the equator three times over.
The volume of concrete poured into the piers and anchorages during the bridge’s construction would be enough to lay a 5-ft (1.5-m) wide sidewalk from New York to San Francisco, a distance or more than 2,500 miles (4,000 km).
The bridge can stand firm in the face of 100 mph (160 km/h) winds.
Each of the bridge’s piers has to withstand a tidal flow of more than 60 mph (97 km/h), while supporting a huge, heavy tower above.
c. 1872: Earliest discussions about building a bridge across the entrance of San Francisco Bay.
1923: California legislature passes a bill to explore the feasibility of building the bridge.
1933: Construction of the Golden Gate Bridge begins in January.
1937: The bridge opens on time and under budgets, to great celebrations.
1985: The one-billionth car passes over the bridge.