Influence of construction loading on deflections in reinforced concrete slabs

This paper describes and analyses a series of tests on one-way spanning slabs, which were carried out at Imperial College London to investigate the influence of peak construction loads on long-term tension stiffening and slab deflections. The work was carried out to investigate the validity of conclusions drawn from the first author's back analysis of deflection data in the Cardington in situ concrete building, which suggested that long-term deflections in slabs could be governed by short-term construction and in-service loads. An improved method is proposed for taking account of the effect of peak construction loads on long-term slab deflections. The method is shown to be more accurate than the rigorous method in Concrete Society Report TR58 which is based on the first authors' analysis of slab deflections at Cardington.