The paper describes how to achieve the specified cover to reinforcement in reinforced concrete structures. The problem of failing to achieve the specified cover is widespread and in the UK alone is reliably estimated to cost £550M each year. Achieving the specified cover is important for the structural, durability and fire performance of structures. It highlights the problem, and describes the development and application of BS 7973 to provide the solution. Chris Shaw, CEng, FICE, FIET, MIStructE, MCMI Consultant
Traditional structures are mainly two-dimensional diagrams - readily conceived and simple to sketch. The third dimension is usually an added complication demanding that structures remain stable in this direction as well. But if we embrace this third dimension (usually one of the lateral dimensions) as an opportunity for greater structural resistance, then we might find many other possible solutions - curvature can become our greatest ally. Three dimensional structures come in many guises, including: • two-dimensional form with a 3D twist • pure, form found tension structures • singly- and doubly-curved compression shells • pre-stressed tension elements combined with struts • lyrical forms that nevertheless are structurally competent • structures that occupy three-dimensional space This paper will touch lightly on all these types of structure using real examples and providing the author’s personal views of some of the issues involved. Examples include: • Brickpit Ring with Durbach Block • Aurora Place Canopy, with Renzo Piano • Royal Agricultural Showground Exhibition Halls with Ancher Mortlock and Woolley • Brisbane Convention and Exhibition Centre with Philip Cox • proposed stadium for Durban with Philip Cox and ArupSport • City of Manchester Stadium, Arup Associates • Khalifa Stadium with Philip Cox and PTW Architects • Marina Bay Bridge with Philip Cox and Architects 61 • Water Cube, with PTW Architects and CSCEC. Tristram Carfrae, MA, RDI, FTSE, MIEAust, MIStructE Principal Director, Arup Arup Fellow