Post-tensioned Discrete Concrete Elements Developed for Free-form Construction

This paper presents a method for the construction of non-uniform precast concrete shell structures from unique parts. A novel method of discontinuous post-tensioning is introduced which allows tension to be taken through the connections. This increases the formal possibilities of the system beyond compression-only funicular forms. It also allows live loading to be catered for without significant thickening of the structure. Most significantly, the post-tensioning system allows for an almost total elimination of falsework a significant impediment to the realistion of complex shell structures. This advancement reduces resources needed for assembly, and increases the overall robustness of the system. Also presented are a series of refinements that add to the geometric precision of individual concrete elements cast in lasercut PET moulds. These include the development of a casting rig used to fix casting moulds in the right position during casting and algorithms to produce mold details to mediate between the unique components and the repeated rig forms. The last design experiment is the most elaborate, demonstrating a pavillion structure which incorporates all areas of development. The successful execution of this design experiment allows us to conclude that the building system in its current state of development is ready to be tested in a scale larger than the typical research pavilion.