Since the rise of 3D Computer Aided Design (CAD) design in the eighties and nineties Octatube has been at the front of the developments. Nowadays, all Octatube’s projects are designed, engineered, calculated and drawn completely in 3D. This provides complete freedom in the geometrical possibilities. Furthermore, the feasibility can directly be tested with the application of many different materials and production methods.
One of the first substantial projects with a complete free form language, was the Town Hall in Alphen a/d Rijn (the Netherlands). By deviating from the well known orthogonal grid and the large quantity of unique elements, the use of 3D CAD was crucial and made it possible to realize this challenging project, completely prefabricated.
In the last years the possibilities in the field of (file to factory-) production like CNC laser cutting, CNC milling and 3D printing has also been used by Octatube to deal with large quantities of unique elements.
Traditionally shaping of glass sheets is done in hot-bending processes, cold–bending of glass sheets however has recently been developed and has important advantages.
In hot–bending, a single or double curve in a glass panel is normally achieved by heating the glass and allowing it to cool in a mould. This process is particularly expensive given that a separate mould needs to be made for each glass shape. Besides any irregularities in the mould will also be visible in the glass. Octatube has been realizing projects with cold-bent glass since 2001. Flat glass sheets are bent and kept in that shape using mechanical pressure at the construction site. Both in single and double curved applications. Cold-bending of framed glass has been used for some time in cylindrical roofs, but it is also possible to cold-bent glass with point fixings. This technique was used by Octatube on the Floriade Paviljoen. During bending, half of the tension applied was used for bending and the other half to take up the wind loading. It is also possible to twist double gazed panels in a frame. For the twisted “spaghetti facade” of the City Hall of Alphen aan den Rijn Octatube used one quarter of the applied tension for cold twisting.
We have thoroughly investigated the theory underlying the bending of glass, allowing us to model and predict the material’s bending and breaking properties. The knowledge we have developed allows us to make superb use of cold-bent single and insulated glass panels. In the atrium roof of London’s Victoria and Albert Museum, fins made entirely of glass carry the glass panels forming the roof. The fins vary in size, with the largest spanning 11 metres in a single piece, and are manufactured in triple laminated glass. C-profiles to clamp the glass fins are attached to the joists with adhesive.
A gridshell is a form- and cross-section-active, lightweight structure, composed of discrete members following a curved free-form shape. Through its shape, a gridshell is designed to carry loading as efficiently as possible, resulting in an efficient, self-supporting structure, able to span large distances using relatively little material. They derive its strength from its single or double curvature and are usually applied to create freeform, geometric or geodesic building skins.
A gridshell is usually based on a grid of many triangles or rectangles. The repetition of the indivudual elements often creates a homegenous appearance.
Through its form, the gridshell offers support for a wide variety of cladding materials such as glass or membranes, while the slender elements allow for light to enter.
Octatube has wide experience with clad-shells and transparant gridshells.