Diagrid and space frame structures

The node, where many members meet at a point, is the critical component and often the most expensive part. Every member must be connected concentrically so their forces pass cleanly through the joint without introducing bending, and proprietary node systems, cast or machined connectors that members screw or bolt into, are used to achieve that on a repeatable basis. We design or specify the nodes for the combined forces of every member framing into them, and the geometry is controlled precisely because a small error in member length multiplied across thousands of members distorts the whole surface.

Stability comes from the geometry itself rather than from added bracing. Because the network is fully triangulated it is stable in every direction, but that also makes it stiff and sensitive to how it is supported; the support points have to allow the frame to expand and contract with temperature while still holding it against wind uplift, which on a large light roof can exceed the gravity load. We analyse the whole structure as a three-dimensional model, tracing forces to the supports, checking the buckling of the most heavily loaded compression members, and confirming that the loss of any one member would not trigger a wider collapse.

Space frames suit long-span roofs where columns are unwelcome: sports halls, swimming pools, exhibition centres, airport terminals, atria and canopies. Diagrids suit tall towers and expressive structural facades where the diagonal grid does the work of columns and bracing at once and is left visible as the architecture. Both are light for the span they cover, can be prefabricated as repeating units, and distribute load so evenly that supports can be widely spaced. Their regular geometry also makes them adaptable to curved and free-form surfaces.

The limits are cost and complexity, not capacity. The many members and precision nodes make fabrication and setting out demanding, so these systems earn their place on long spans and signature buildings rather than ordinary ones where a simple beam is cheaper. The slender compression members must be protected against buckling and, in steel, against fire and corrosion, and the large surface area means wind and temperature effects are significant and must be modelled carefully. We handle the three-dimensional analysis, the node design and the movement details so the finished structure matches the geometry it was drawn to.