Edge Supported Shells


The stresses and deflections in single barrel vaults (or end bays of multiple vaults) may be reduced by using columns or walls to support the edges. This makes it possible to design a single barrel shell for a large auditorium or gymnasium without using intermediate stiffeners. Most of the load is carried to the end stiffeners and columns. The intermediate columns merely act as a vertical support and do not carry lateral load. If there are continuous windows at the sides, the columns may be thin steel pipe columns which appear to be window mullions.

It is a basic concept of shell structures that edges, wherever possible, should be supported rather than leave an expansion space between the top of the wall or windows and the shell. It may be argued that it is not really necessary to fireproof these columns since the structure is capable of supporting itself in the event of a fire which will melt the steel columns.

The spans and widths of this type of structure may be increased by using ribbed slabs or waffle slabs or other methods of increasing the strength without increasing the weight.