Towards an efficient design of carbon reinforced concrete elements: from prismatic beams to origami-based folded shells

The pursuit of structurally efficient elements that minimize material consumption while meeting structural requirements is becoming increasingly important due to escalating global environmental concerns. Compared to steel reinforced concrete, it is believed that modern high-performance materials such as carbon reinforced concrete (CRC) can provide more sustainable designs. However, this is only possible if both concrete and carbon reinforcement are properly utilized. While carbon reinforcement offers light weight, corrosion resistance, and superior tensile strength, it lacks ductility. Therefore, the brittle character of both CRC material components can lead to a premature failure in one component, leaving the other underutilized. An efficient beam design can only be achieved by carefully tuning the cross-sectional design parameters, and for spatial elements, a material-minimized design often means complex, thin-walled 3D forms with unsustainable, single-use formwork. Therefore, design solutions are needed at both the conventional prismatic beam level and the innovative lightweight spatial structure level. For beams, a re-evaluation of the current design philosophy developed for steel reinforced elements is required, and innovative design paradigms need to be developed that enable modular, easy-to-manufacture and high-performance spatial elements. This thesis contributes to the design and development of material-efficient CRC elements at the two aforementioned design levels. First, numerical and analytical models are developed to evaluate the flexural behavior and material efficiency of prismatic beams, followed by a test series of CRC beams with different configurations supporting the validation of the models. Based on the developed analytical model, closed-form formulas for material strength utilization are derived accompanied by the conceptualization of an efficiency-oriented flexural design concept. The numerical model is then used to perform systematic parametric studies comparing the flexural behavior and ...