Thin-shell Concrete Floors for Sustainable Buildings
Rapid urbanisation and population growth is driving unprecedented levels of building construction. Over the next 40 years, approximately 230 billion square meters of new floor area will be constructed globally, a doubling of existing building stock. Already, the production of concrete and steel accounts for a third of worldwide industrial CO2 emissions, representing a major opportunity, and responsibility, for structural engineers to contribute towards a low-carbon future through efficient design. A significant majority of the structural material in a typical building exists within the floors, making these a prime target for material reductions. This dissertation shows that thin shell concrete floors are a viable alternative to typical slabs and beams in multi-storey buildings. Switching the dominant structural behaviour from bending to membrane action increases efficiency, enabling significant embodied carbon reductions.
A system is proposed featuring pre-cast textile reinforced concrete shells of uniform thickness and shallow depth, supported at columns, with a network of prestressed steel tension ties. A lightweight foamed concrete fill is cast above the shells to provide a level top surface and transfer floor loads to the shell. The structural behaviour of this system is explored through a series of computational and experimental investigations, leading to refinement of the design, exploration of construction methods and the development of a complete design methodology incorporating novel theoretical work. The shells feature optimised singly-curved groin vault geometry. This provides efficient structural performance whilst simultaneously minimising construction complexity. Thus, a practical and scalable solution is proposed, which is shown to offer considerable embodied carbon savings over typical concrete and steel floor structures.
This work provides a robust platform for future refinement and large-scale implementation of thin-shell concrete floors for sustainable buildings.