One of the the biggest urban greenhouses in the UK spans the centre of Sheffield. Filled with sago palms, bamboo and tourists, the heated glass arcades form the heart of a £120m regeneration scheme.

The Sheffield Winter Garden is a glazed structure of Glulam* arches, designed to achieve more sustainable construction. The 75m long structure provides a 20m high internal space with a clear 22m span. The requirement to maximise the internal space without internal supports led to the development of glued laminated-timber parabolic, spanning the width of the gardens.

The arch forms have been evolved from an inverted catenary, minimising bending forces under the dead loads of glazing, reducing the size of the Glulam sections.

As the use of overseas technical guidance has already resulted in correspondence with the committee responsible for drafting timber design codes in the UK, the project will help develop the UK knowledge base of large scale timber construction to a level comparable with the rest of Europe.

* Glued laminated timber ("Glulam") is made by forming and gluing strips of timber to generate large structural members in shapes that can suit both their structural duty and architectural function.