Shaping concrete: An investigation of knitted formwork for concrete casting

Abstract

Double-curved geometries have never been easier to design with the advancements in 3d software. However, realizing these structures are often complicated, time consuming, and wasteful. The formwork for casting concrete structures represents more than half of the total cost for complex geometries making it unfeasible in most cases. Not only does this limit the architectural expression but also the engineering possibilities. Admired structures, such as the ones built by acclaimed engineers like Felix Candela and Pier Luigi Nervi, rely on curved geometry to carry the load efficiently. In this thesis, knitted formwork is examined as an alternative production method for double-curved geometries. The production method is studied to optimize the production phase to increase the feasibility of such complex structures. In addition, the method is also studied to produce efficient structures to reduce material usage in the structural system. The exploration of knitted formwork is done in a design study where models of varying scales are produced. To complement the physical models, computational simulations are performed to support the design process by generating knitting patterns, form-finding and analysis of the shell structure. The final design is a result of an iterative design process where the fabrication method, as well as the structural system, is expressed. Only when these are in symbiosis can the design be a representation of efficiency.