Ruled based constructions or the materialization of a line in motion

Abstract

Through the work of the Architect and Engineer Felix Candela on Hyperbolic Paraboloid surfaces for thin concrete shell construction, the paper retraces how ruled geometries (generalized by a sequence of rotating lines) directly regulate procedures of construction for concrete formwork, made of straight timber elements. From the conception of three timber structures, it is discussed how such geometrical principles are further explored spatially, structurally and materially. Finally, a series of subsequent physical experiments are put forward in search of new topologies, generated from the description of a line moving in space. An initial investigation on timber formwork research is presented through the realization of three timber structures; The Pinch, Sweep and Warp. Sequences of changing wooden trusses capture the movement of a line to support ruled decks performing as new active grounds. In doing so, the trusses are organized transversally for the Pinch, tangentially for the Sweep and longitudinally for the Warp. The results are a series of three small scale social programs: a library, a play area and a roadside marketplace. Located in remote mountainous landscapes (Yunnan, China), each project was designed with a strategy of maximizing the use and experience of the surrounding landscape. They were each built with students and with the help of a local timber workshop, developing construction methods for adapting highly articulated geometries to simple traditional techniques. Situated at the intersection of teaching and research, experimentation and on-site construction, complex geometry and local craftsmanship, these design-build projects engage with full scale construction in difficult sites through experiential learning. A live prototyping exercise further speculates on the line as vehicle to describe geometries of revolution. With the support of a 5-axis custom-made automated hot wire, serving as the main research tool, specific protocols for synchronized motions (4 translations and 1 rotation) are inputted. As a result, new slab topologies defined by movement and time emerge, that would be difficult to preconceive through other means of (digital) fabrication. These protocols of motions are then put to use to section blocks of EPS foam into part-formworks for thin shell concrete casting. By virtue of being described by successions of straight lines, these intricate slabs retain effective structural properties and a direct link to timber formwork and to full scale construction. As much prominence in (digital) fabrication has been placed on surface definition machined from sheet materials, the presented prototyping procedure seek to reinstate the merits of working with volumetric materials. To this effect, a parallel is drawn with stereotomy. The effective method of stone carving invented by Philippe De L’Orme also made use of 2d geometries to guide the stone cutter in the carving of a block. Although this time, by operating internally in the slicing of a block from the automation of a line moving in space, new spatial articulations in Architecture may emerge again from active geometries solely defined by time and movement.