Concrete is the most widely used artificial material around the world, the productionof which is associated with over 5% of total carbon emissions. Conventional concrete structures have prismatic geometries partly due to rigid formworks, resulting in inefficient use of materials. Fabric formwork has been used to enable structural optimisation, capitalising on the flexibility of woven fabrics and unique fluidity of wet concrete. However, a significant drawback is the complexity of fabricating steel reinforcement cages for flexibly formed concrete elements, which normally have variable-depth geometries. Both curving flexural reinforcement into the designed profiles and producing shear links of variable dimensions requires additional costs of time and labour.In this dissertation, a new reinforcing system, Wound-Fibre-Reinforced Polymer (W-FRP), is proposed as a durable alternative for the reinforcement of flexibly formed concrete beams, thereby unlocking the potential to minimise carbon emissions associated with concrete construction. An automated method has been developed to produce W-FRP cages, which are light-weight, easily transported and adaptable to many beam geometries created using fabric formwork. Based on the design and optimisation process developedin this research, three series of structural testing were undertaken to investigate the structural behaviour of W-FRP reinforced concrete beams with both prismatic and variable-depth geometries. Modelling and parametric analysis are undertaken to achieve the optimum design of fabric formed T beams reinforced with W-FRP. Through testing and analysis, further practical guidance is provided for designers.The experimental and theoretical research in this thesis has shown the great effectiveness and constructability of the W-FRP reinforcing system, with which up to 23% concrete saving can be achieved without compromising structural performance. The geometry, W-FRP shear reinforcement, and anchorage design have been shown as the key factors influencing the structural behaviour of W-FRP reinforced beams. It is possible to optimise the W-FRP patterns to achieve up to 50% increase in shear performance without additional reinforcement use. Capitalising on flexible fabric formwork and W-FRP shear reinforcement, this thesis demonstrates that constructing more durable and sustainable concrete structures can be achieved in a feasible and practical manner.
|Date of Award
|11 Oct 2018
|John Orr (Supervisor), Tim Ibell (Supervisor), Antony Darby (Supervisor) & Mark Evernden (Supervisor)