Introduction :Shells or skin space roofs are preferable to plane roofs since they can be used to cover large floor spaces with economical use of materials of construction.

The curved space roofs require 25 to 40% less materials than that of the plane elements.

Structurally the shell roofs are superior since the whole cross section is uniformly stressed due to the direct forces with
negligible bending effects.

Due to this reason the thickness of shells is usually very small in the range of 75mm to 150mm.

Shell roofs are generally adopted for hangers, sport auditorium, exhibition halls, industrial buildings and a variety of other
large span structures where uninterrupted floor space is required.

Shell roofs are architecturally very expressive and have been used for domes by Romans. Recent advances include the construction of shell structures using prefabricated shell elements.

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