Nowadays Glass has become a majore lementin designing modern commercial or public buildings.Load -bearing structures are wanted to be delicate systems with a transparent feel.The use of steel in load-bearing structures improves the transparency of facades because it has been possible to keep the load-bearing structure slender. Curtain wall meaning a set of aluminum profile like Mullion, Transom, Glass panel. There are three types of curtain wall.
Above three, we used the unit panel system which is also called as unitized system. This system comes pre assembled; it can be pre-glazed at the factory or shop, or glazed on-site. As such, it minimizes field labor and erection costs, and promises a shorter installation period than the stick system. Quality control issues can be significantly reduced in terms of site labor, especially with pre-glazed units, but assembly at the plant and transportation (due to bulk) increases its cost. Another disadvantage to preassembly is any site changes become difficult to accommodate.
Assembly must be carried out in a specific sequence to ensure a proper fit. In a unitized system, the manufacturer must rely on qualified installers to ensure that the air seals are properly installed between the split mullions. Nevertheless, the unitized system is the most popular façade system according to on manufacturer and it has performed satisfactorily when installed correctly.
The Curtain Wall is designed to resist and handle all the imposed loads on it as well as keep air and water from penetrating in the building.The loads imposed on the curtain wall are transferred to the building structure through structural interface(i.e.brackets) which attaches the mullions to the building. The curtain wall is designed for the following Loads.
1. Dead Load
2. Wind Load
The main aspect in designing steel and glass joints is to consider the special material properties and behavior of glass. Glass fractures brittle without a forewarning.These properties and behavior concern normal float glass as well as laminated glass and safety glass.