The objective of many of the current projects is to produce practical guidance for industry through an understanding of fundamental behaviour. Reinforcing bars are produced with an epoxy coating to improve corrosion resistance and to combat problems of corroding concrete structures. A side effect of the coating is a reduction in the bond between reinforcement and concrete which is necessary for the two materials to act compositely. The outcome of the research will be modification to existing rules to take account of this reduction. Repairs to concrete structures generally require that concrete surrounding reinforcement be removed before fresh concrete is recast.
Current practice is to prop a beam while the repair is carried out.
However, current research shows that a beam may not lose much strength even when concrete is removed over a large proportion of the span. Work to date suggests potential savings on temporary support. Speeding up of work may be possible and recommendations for repair procedures are being prepared. An ongoing programme of research into the behaviour of structural concrete members has led to the development of a flexure-shear interaction design model which takes into consideration the interactive relationship which exists between shear and flexure. This model was based on the conclusion that only one behavioural mechanism exists within the beam structure ie the confined compression region of the concrete is the main element which resists shear thus confirming that truss action is not necessarily required to transmit the loads to the supports.