A concrete shell, also commonly called thin shell concrete structure, is a structure composed of a relatively thin shell of concrete, usually with no interior columns or exterior buttresses.The shells are most commonly flat plates and domes, but may also take the form of ellipsoids or cylindrical sections, or some combination thereof. Shell construction began in the 1920s; the shell emerged as a major long-span concrete structure after World War II. The most popular types of thin-shell structures are: Concrete shell structures, often cast as a monolithic dome or stressed ribbon bridge or saddle roof The first concrete shell dates back to the 2nd century. The ideal thin shell must be capable of developing both tension and compression. Thin parabolic shell vaults stiffened with ribs have been built with spans up to about 300 ft (90 m). A rapid and inexpensive process for constructing thin shell concrete architectural shapes has been developed in the research department at A and M College of Texas. Types.