Portal scaffold is one of the most widely used scaffolds in construction. Because the main frame is in the shape of “door”, it is called portal or portal scaffold, also known as Eagle frame or gantry. This kind of scaffold is mainly composed of main frame, cross frame, cross diagonal brace, scaffold board, adjustable base, etc.

Portal scaffold is one of the most widely used scaffolds in construction. Because the main frame is in the shape of “door”, it is called portal or portal scaffold, also known as Eagle frame or gantry. This kind of scaffold is mainly composed of main frame, cross frame, cross diagonal brace, scaffold board, adjustable base, etc. Portal scaffold is a construction tool first developed by the United States in the late 1950s. Because it has the advantages of simple assembly and disassembly, convenient movement, good bearing capacity, safe and reliable use and good economic benefits, it has developed rapidly. By the 1960s, Europe, Japan and other countries have successively introduced and developed this kind of scaffold. In Europe, Japan and other countries, the use of portal scaffold is the largest, accounting for about 50% of all kinds of scaffolds, and many professional companies producing portal scaffolds of various systems have been established in various countries.

Since the 1970s, China has successively introduced portal scaffold system from Japan, the United States, Britain and other countries, which has been applied in the construction of some high-rise buildings and achieved good results. It can be used not only as internal and external scaffolds for building construction, but also as floor slab, beam formwork support and mobile scaffold. It has more functions, so it is also called multi-functional scaffold.

By the early 1980s, some domestic and manufacturers began to imitate the portal scaffold. Until 1985, 10 portal scaffold manufacturers have been established successively. The portal scaffold has been widely popularized and applied in the construction projects in some areas, and has been welcomed by the construction units of Guangda. However, due to the different product specifications and quality standards of each factory, it brings some difficulties to the use and management of the construction unit. This has seriously affected the promotion of this new technology.

By the 1990s, this kind of scaffold had not been developed and was less and less used in construction. Many gantry scaffold factories were closed or switched to production, and only a few units with good processing quality continued to produce. Therefore, it is necessary to develop a new type of portal tripod in combination with the architectural characteristics of our country.