Answer by A Quora admin:
The Beijing National Stadium
World’s largest steel structure, Beijing National Stadium also known as the Bird’s Nest is a stadium in Beijing, China. This astonishing structure looks more like a public work of art than an Olympic stadium. Designed by the Swiss architects Jacques Herzog and Pierre de Meuron for use throughout the 2008 Summer Olympics and Paralympics.
- The elaborate design incorporates Chinese symbols and mythology. Consisting of about 26 miles of unwrapped steel, the stadium is made up of two independent frames that are set 50 feet apart—an inner concrete red bowl for seating and an outer steel frame weighing 42,000 tons. The original design called for a retractable roof. That was later removed from the plans so the structure could more easily meet seismic requirements and also for budgetary reasons.
- This recent engineering wonder is one of the most energy-efficient and environmentally friendly stadiums in the world. During the winter, underground geothermal pipes heat the indoor part of the stadium. Underground cisterns collect and store rainwater for irrigation and for use in restrooms.
The Laerdal Tunnel
- To connect the Norwegian cities of Laerdal and Aurland highway engineers were forced to solve a small problem: the Hornsnipa and Jeronnosi mountains. Instead of going around the obstacles, they decided to go through them. The result was the Laerdal Tunnel, which runs through solid gneiss rock for 15 miles (24 kilometers), earning it the title of the world's longest completed road tunnel.
- Excavating such a structure is only one of the challenges. Designers also have to ensure that motorists can make the long, underground trek without succumbing to "highway hypnosis." To address this problem, the Norwegian Public Roads Administration called in a team of psychologists to make sure the finished roadway was as stimulating as possible. The agency recommended including blue lights and gentle curves to keep drivers engaged. They also suggested that the final tunnel be divided into four sections to help reduce monotony.
- Motorists entering the Laerdal Tunnel today might not notice these design enhancements, but they'll certainly appreciate them when they emerge safely into daylight after the 20-minute journey through the middle of a mountain.