Kaloyana Kostova, PhD
Design and constructability of fabric-formed concrete elements reinforced with FRP materials
Concrete has many advantages as a low cost and sustainable material. However, more than 5% of the planet’s total carbon emissions are associated with the production of cement, which, in fact, is predominantly due to the large volume of concrete used worldwide. It is known that traditionally designed concrete structures typically use more material than structurally required and, therefore, an important question is whether material demand can be reduced through structural optimisation. A major drawback from optimised design, however, is the cost and complexity of producing conventional rigid moulds. Fabric formwork is emerging as a new method for construction, gaining popularity among architects and engineers for the opportunity to build unique forms and to shape concrete elements efficiently. Porous fabrics, acting as controlled permeability formwork, also have proven effect on the durability characteristics of concrete. While fabric formwork has a profound potential to change the appearance of concrete structures, the shapes cast in fabrics are not defined in advance and have been often created unintentionally. The design of load-bearing reinforced concrete structures, however, requires accurate form-prediction and construction methods for securing steel reinforcement inside flexible fabrics, which presents a number of constructability challenges. For example, cover formers cannot be used to ensure adequate thickness of protective cover, inevitably affecting the acceptance of such structures in practice. This research has demonstrated that non-corrodable FRP reinforcement can be incorporated more easily than steel bars in fabric-formed concrete due to its light weight and flexibility, while it is possible to ensure ductility of such structures through confinement of concrete using FRP helices. A novel splayed anchorage system has been developed to provide end anchorage for optimised sections where standard bends or hooks cannot fit. This work also provides an experimentally verified methodology and guidance for the design and optimisation of fabric-formed elements.
Supervisors: Dr Antony Darby, Professor Tim Ibell, Dr Mark Evernden
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