free download PNG images :Skyscraper

Skyscraper is a high, continuous living building with many floors. When the term was first used in the 1880s, it described buildings of 10 to 20 stories, but now it describes one of at least 40 to 50 stories. Skyscrapers are mainly designed for office, commercial and residential purposes, also known as high-rise buildings, but the term "skyscraper" is usually used for buildings higher than 50 m (164 ft). For buildings over 300 m (984 ft) in height, the term "super high rise" can be used, while skyscrapers over 600 m (1969 ft) are classified as "super high rise".

A common feature of skyscrapers is the steel frame supporting the curtain wall. These curtain walls are either supported on the lower frame or suspended from the upper frame, rather than placed on the load-bearing walls of conventional structures. Some early skyscrapers used steel frames, which allowed them to build higher bearing walls than reinforced concrete buildings.

The walls of modern skyscrapers are not load-bearing. Most skyscrapers are characterized by large window areas made of steel frames and curtain walls. However, the curtain wall of skyscraper can imitate the traditional wall with smaller window area. Modern skyscrapers usually have tubular structures and are designed like hollow columns to resist wind, earthquake and other lateral loads. In order to appear slimmer, reduce the exposure of wind, and spread more sunlight to the ground, many skyscrapers have some setbacks in design, sometimes it is also necessary in structure.