The shiny, modern glass building is a landscape of a big city. Who created the facade of the building?
Whimsical people are actually the most creative people. The original meaning of the window is the "hole on the wall." In 1919, some people wanted to expand the glass window indefinitely and even replace the entire wall. This person is the German architect Mies van der Rohe, who was one of the four most famous modern architectural masters in the world in the mid-20th century. In 1921, Mies modeled his whimsical ideas - the exterior walls of the entire building were made of glass, called "glass buildings." He declared that he would combine the window with the wall, and the glass exterior would be both a transparent window and a solid wall.
Mies's "Glass Building" was just a vision. In 1976, the famous Chinese-American architect Peter Pei made the idea of Mies into reality. He built a 60-story Hancock Building in Boston, which is a glass exterior. Skyscrapers. This novel building with a transparent body and a mirror-like exterior is one of the brightest things in the world. It suddenly caused a sensation in the United States and caused a sensation in the world. The glass facade is called the glass curtain wall, and Mies is known as the father of the glass curtain wall.
However, the good times did not last long and the applause for the Hancock Building soon became a criticism. The glass curtain wall of the building has used a total of 1.4-by-3.5-meter glass of 10 to 344 pieces, and it took more than 2,000 blocks in three years! Beautiful tall buildings are full of holes. This is because the strength of those glasses is not enough, and the strength of the steel frame supporting the glass is not enough. After five years of renovation, the Hancock Building was not easy to cure the "scars" on the external walls.
In recent decades, after continuous improvement, the quality of glass curtain walls has been significantly improved: First, "tempering." After tempering treatment (heat treatment), the impact strength of the glass is increased by 3 to 5 times than that of ordinary glass, and even if it is broken, it is only broken into small pieces of glass with no sharp corners. The second is "hollow." Making the curtain wall glass double (or even three layers), with dry air or inert gas between the two glass sheets, can greatly improve the insulation, heat insulation, and sound insulation properties. According to measurements, when the outdoor temperature is -10°C, the temperature in front of the single-layered glass window is -2°C, while the room temperature in which the triple-layered insulating glass is used is 13°C. It should be emphasized that the air filled in the hollow glass must be dry, which is to prevent the condensation of water vapor in the inner layer in the winter, affecting the transparency. The third is "double silver." The glass is coated with two layers of extremely thin silver film. This "double silver glass" can transmit visible light well but reflect the sun's thermal radiation (infrared rays). In the hot summer, double-double-silver insulating glass can transmit 90% of visible light and block 90% of the solar radiant heat.
The improved glass curtain wall has a new look and is very popular. It has "unlimited scenery inside and out." From the outside, the high-rise building seems to be wearing a beautiful glass coat; into the building, the light is transparent, everywhere is the "large screen", unlimited scenery outside the window panoramic view. During the daytime, the interior lighting has greatly reduced the use of electricity for artificial lighting. At night, the glass curtain wall has been transparent and the building has become a “Crystal Palace”. There is another fascinating view of the brightly lit city.
Due to these advantages of architectural design of glass curtain walls, it quickly swept the world. Manhattan, New York, Ginza, Hong Kong, Causeway Bay, Pudong, Lujiazui, Shanghai, have become a gathering place for glass curtain wall buildings. Although the glass curtain wall entered China in 1984, but in a short period of 20 years, China has become the world's number one "glass curtain wall big country": the glass curtain wall area has soared to 200 million square meters, accounting for 85% of the world; China's production of curtain wall glass accounts for 75% of the world's total. In Shanghai alone, there are more than 3,000 buildings that wear gorgeous glass curtain coats.
However, the glass curtain wall also has its disadvantages: First, although the quality of the glass has been greatly improved, it cannot completely eliminate the self-explosion phenomenon. In order to avoid the "glass rain" from falling to the pedestrians, a green belt is usually set up around the glass curtain wall building; Second, the reflection intensity of glass curtain walls is about 10 times that of ordinary decorative materials. The “light pollution” that results from this will cause harm to human health. Therefore, it is stipulated that residential buildings and school buildings must not use glass curtain walls.