Free-form structures and domes can be used to cover large expanses of space in a variety of venues. Arenas, atria, museums, houses of worship, and industrial buildings all require large covered areas without intermediate columns. In order to realize these large structures effectively, design professionals should shape these buildings to take advantage of form both as a structural element and for architectural expression. But few construction systems allow full geometric freedom and economic efficiency.
The Lead Frame System
LF, and the building system used to realize it, are clearly interrelated. Unless the right combination of structural system, the resulting structures may not be feasible. Solutions with joist, for example, are limited to planar trusses in an array, and work in only one direction. Solutions with machined joints, such as ball-joint systems, must minimize the number of nodes, as these are expensive. Thus, with traditional construction systems, some geometries become impractical even if they could result in material savings. LF's building system solves these problems.
LF system is versatile. It features an extruded, universal and strong joint, human-scale modules, dense packing volume, and easy installation that requires the use of minimal equipment. These virtues allow for unlimited forms. And the judicious selection of form results in beautiful and efficient long span structures.
LF structures are built with lightweight and strong galvanized steel or aluminum tubes, prefabricated in a computer-driven manufacturing line. The connection of tubes and hub is compact, simple and extremely efficient, with no field-welding required.
The connecting hub is an extruded aluminum cylinder with several threaded slots. Each tube is formed at the ends into a matching linear shape that slides into the hub's slot. When all the tubes in a certain hub have been assembled, the joint is completed with washers and a single bolt.
Once complete, the joint is strong, sometimes even more than the joined tubes themselves. Most importantly, the tubes resist bending moments at the joint. This allows for the deck or cladding of the structure to be affixed directly to the space frame members, without secondary structural purlins that can be as heavy as the frame itself in other construction systems. This feature also permits many variations on basic geometries that are simply not possible with conventional bolted or welded connections.
Viewed up close, a LF structure is clean and elegant – and from a distance, its light and airy quality complements the design geometry of the structure. LF achieves a balance of form and function that is simply not possible with conventional bolted systems. Almost any structural geometry is possible with the LF system, including flat and faceted space frames, singly curved arches and vaults, double curved domes and arbitrary freestyle shapes.
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