Masted structures
The concept of masted structures is not new, but they have only recently become popular as a means of providing lightweight structures for general use.
Masted structures have been used in bridge building and tented structures for decades but only more recently as a means of providing lightweight structures for general use. A significant example of an industrial shed with a masted structure was the Fleetguard Distribution Centre in Quimper, Brittany designed by Richard Rogers and Partners with Ove Arup and Partners in 1979. Here the 355mm diameter steel columns on an 18 x 18m grid support the flat roof from above with tension rods which reduce the span to 6m, thereby reducing the size and weight of the structural members as well as the overall bulk of the building.
Fleetguard was followed soon after by another striking masted shed for Renault in Swindon by Foster Associates and Ove Arup and Partners. In this case the concept was for a series of 24m square umbrella modules which could be grouped in any configuration and this was achieved with a portalized structure of undulating beams supported from tubular steel masts with tension rods.
A variety of layouts are possible for the arrangement of masts and supported structure, designed to suit individual requirements.
The Inmos Microprocessor Factory in South Wales by Richard Rogers and Partners with Anthony Hunt Associates uses a central masted spine which supported 36m clear span trusses, propped at the ends.
This solution was derived from the need for extremely high levels of mechanical services plant required in the production process which were housed in a gantry above the circulation spine from which they distributed in the structural zone above the roof.
The masted structure for East Croydon Station by Alan Brookes Associates with YRM/Anthony Hunt Associates demonstrates another approach with double column masts on the perimeter supporting pin-jointed beams which span the 55m across the railway lines below. Obvious economies are achieved by the tension supports which allow the truss depth to be reduced to only 1.8m.
