Form-Finding approach for flexibly formed concrete elements

There is no reason why concrete elements should be prismatic. Concrete is mouldable and can be cast in efficient forms which follow the stresses varying along the length of a concrete element. One option to achieve this is to use fabric as flexible formwork. Fabric deforms under the hydrostatic pressure exerted by wet concrete during construction, creating the shape of hardened concrete. The final shape needs to be known in advance to be able to perform the analysis and design of structural elements. This paper presents a form-finding approach capable of predicting the shape in cross-section of flexibly formed concrete elements. The approach is shown to predict geometry appropriately, based on the results of an experimental investigation, particularly when applied to complex shapes. The influence of construction tolerances, practical aspects and limitations of the approach are also discussed.