Types and Forms of Shell Structures

VAULTS WITHOUT STIFFENERS

Stiffeners on barrel shell vaults are expensive to build and interfere with the interior space if ties are used below the shell. It is possible to eliminate, or to greatly reduce the size of the stiffeners if the thrusts form the shells are taken by the columns. The total force at an interior column is counterbalanced by the thrust of the shells on each side, but the first outside column must take all of the thrust of a shell.

The high thrust at the top of the column must be resisted, in turn, by large footings. This type structure will cost less than the conventional barrel shell with stiffeners if the extra concrete and reinforcing required for the large columns and footings is less than the concrete and reinforcing and forming for the stiffeners.

At the junction of the shell and the column, added thickness of the shell will be required to transfer loads to the column and the element of shell between columns must be designed for the load transfer.