Design of Double Curved Self Spanning Horizontal Laminated Glass

There is a desire in architecture to design and achieve transparent canopies and glazed rooves that are free from the visual clutter and the structure required to support the transparent elements.

Continual development in manufacturing have resulted in longer and more courageous shapes to be formed in laminated glass and there are many examples of long (up to 9m) elements with deep cross sections used in glazed walls.

However, the design of profiled laminated glass acting as a deep section under long term load has no precedence nor codified design guidance. There are many papers and test studies completed on composite laminated sections but little has developed in terms of design rules for the masses.

To make life more complicate there is significant variance between the design philosophy of international glass design codes for flat glass elements acting as a membrane, let alone how to address deep profiled sections.

The changes in manufacturing have far outstripped developments in design codes, leaving the design and assessment of such glazed structures up to the individual design team and requiring a certain amount of development from first principles. This leaves the design open to interpretation and the vagaries of “expert” opinions.

This paper looks at the design requirements and design of horizontally situated large format laminated glass with a double curved cross section profile to act as a self-supporting roof element.

Our paper also includes limits of manufacturing and the impact that this has on the design of glass under permanent creep loading as well as under transient and short term loads including those related to thermal stress.

The paper offers a design method and validation process to meet current design codes along with our investigations into other important environmental related effects brought on by the design requirements of increased transparency