The Golden Gate and Naruto Ohashi Bridge / Naruto Whirlpools

The Golden Gate

1. The Golden Gate

The North American strait to connect the transportation from San Francisco Bay to the Pacific Ocean is called The Golden Gate. Its colour is red.
 Today, the Golden Gate Bridge is maintained by 200 employees who work together to accomplish the critical day-to-day maintenance and safe roadway operations. Bridge operations personnel are responsible for public safety, security, toll collections, managing the flow of traffic and emergency response. The bridge captain (formerly known as the toll caption) oversees 24/7 operations that include toll collections, security and roadway service.


An urban myth, the Golden Gate Bridge does not get painted end to end in perpetuity. Rather, painting crews inspect critical bridge components and make touch-ups as needed, protecting the bridge’s steel components from the high salt content in the air. The distinct gold color is actually International Orange and was inspired by the original primer color. Black, grey and a yellow and black striped pattern were also considered, but the orange hue of the primer seen during construction seemed to perfectly meld into the surrounding landscape and accentuate the bridge’s art deco architecture. The original lead-based paint was replaced in the 1960s with an inorganic zinc silicate primer and acrylic emulsion topcoat.

In addition to constant maintenance, the Golden Gate Bridge has undergone several major retrofits aimed at improving stability and increasing capacity. Incredibly, the bridge suffered no major damage after the 1989 7.1 earthquake that killed 68 people, injured 3,700, rattled nerves and caused $6 billion in damage throughout the region, including the collapse of the upper deck of the nearby Bay Bridge. A three-phase Seismic Retrofit Design and Construction Project was implemented shortly afterward, enabling the bridge to now withstand an 8.3 magnitude earthquake. The retrofit cost $661 million and was funded by increasing tolls and grants. Meanwhile, the recent construction of the southern approach was funded with stimulus dollars.


 2. Naruto Ohashi Bridge / Naruto Whirlpools

Naruto Strait, view from Awaji, with flow from the right

The Ōnaruto Bridge (大鳴門橋 Ōnaruto-kyō^?) is a suspension bridge on the route connecting Kobe with Naruto, Tokushima, Japan. Completed in 1985, it has a main span of 876 metres (2,874 ft). Although it is one of the largest bridges in the world, it is dwarfed by the Akashi-Kaikyo Bridge, which is on the same route. In 2004, 6.8 million cars and trucks crossed this bridge, translating into a daily average of about 18,600.

The Naruto whirlpools (鳴門の渦潮 Naruto no Uzushio^?) are tidal whirlpools in the Naruto Strait, a channel between Naruto in Tokushima and Awaji Island in Hyōgo, Japan.
The strait between Naruto and Awaji island has a width of about 1.3 km (0.81 miles). The strait is one of the connections between the Pacific Ocean and the Inland Sea, a body of water separating Honshū and Shikoku, two of the main islands of Japan. The tide moves large amounts of water into the Inland Sea twice per day and also removes large amounts of water twice a day. With a range of up to 1.7 m (5.6 ft), the tide creates a difference in the water level of up to 1.5 m (4 ft 11 in) between the Inland Sea and the Pacific. Due to the narrowness of the strait, the water rushes through the Naruto channel at a speed of about 13–15 km/h (8–9 mph) four times a day, twice flowing in and twice flowing out. During a spring tide, the speed of the water may reach 20 km/h (12 mph), creating vortices up to 20 m (66 ft) in diameter.
The current in the strait is the fastest in Japan and the fourth fastest in the world after the Saltstraumen outside Bodø in Norway, which reaches speeds of 37 km/h (23 mph), the Moskenstraumen off the Lofoten islands in Norway (the original maelstrom), which reaches speeds of 27.8 km/h (17.3 mph); and the Old Sow whirlpool in New Brunswick, Canada, which has been measured with a speed of up to 27.6 km/h (17.1 mph).
The whirlpools can be observed from ships, or from the Naruto Bridge spanning the strait. The suspension bridge has a total length of 1,629 m (5,344 ft), with the center span over the strait having a length of 876 m (2,874 ft) and a height of 41 m (135 ft) above sea level. A good view is also possible from the shore on Awaji island.

Under the on the southern side of Japan is the strait where the Seto Inland Sea meets the Pacific Ocean. This collision produces some pretty fantastic whirlpools when the tide is right. You can see them from right up close on the Uzushio Cruise tour that departs from Fukura port.


Source: 
http://www.worldhighways.com/sections/key-projects/features/golden-route-to-success/
http://heart-of-japan.com/2013/03/18/ten-things-to-do-on-awaji-island/ https://en.wikipedia.org