The Space Deck was a British modular system introduced to market in 1950s, made of inverted pyramids (half-octahedrons) placed side-by-side and connected to each other. The top layer of the Space Deck was made of steel angles (L2x1.5x1/4 for light units and L2.5x2x5/16 for heavy units).
The pyramid units were shop-manufactured in special high accuracy jigs by welding the components to each other. Once assembled, the units are connected to each other using tie bars and bolts. The tie bars are connected to the bosses of the units and form the bottom layer of the spatial structure. There are main and secondary tie bars.
The main tie bars are joined at the boss directly, and the secondary members are placed perpendicular to them. All tie bars are threaded at one end with a right hand thread and a left hand thread on the other end. The assembly of this system is done by bolting the adjacent unit trays and connecting the tie bars between the bosses next to each other.
Space Deck Components
Space Deck Assembly
The modules could be supported at either the top or bottom layer. The span/depth ratios were about 25-30 for supports all along the edges, and reduced if only supported at the corners. The typical modules were 48 in. x 48 in. with depth of 30 in. or 48 in., 60 in. x 60 in. with depths of 48 in. or 60 in., and 80 in. x 80 in. with a depth of 80 in..
This system at one time was widely used for schools and office building structures. The top chord (layer) may also be as purlins to support a deck, which results in cost savings and simplification in the deck connections to structural members. Adjustment of the tie bar screws provided cambering for roof applications. Pitched roofs, shallow domes, and barrel vaults could be constructed using this method.
Space Deck units could be nested and stacked over each other to facilitate transportation. Workers generally assembled them on the ground and erected them using lift slab method.
Using this system a maximum span of 120 ft could be achieved with a unit depth of 3 ft. Large spans [up to 150ft] were also possible with larger modules. For spans up to 100 ft x 100 ft, the structure self-weight was about 4-5 psf. This system has been used all over the world, particularly in England, Scotland, USA, Singapore, Italy, Belgium, Africa, and the Middle East for schools, hospitals and industrial buildings.
The main disadvantage of this system is that it could only be used in square-on-square offset configuration.
