Tests up to failure of a reinforced concrete Hennebique T-beam

Reinforced concrete constructions of the first generation (pre-1914) form part of our heritage and therefore should be preserved for future generations. Few experimental studies have been conducted on Hennebique continuous structures to estimate the actual bearing capacity of this reinforced concrete system, which was the most popular in many European countries at the turn of the twentieth century. Important information is therefore often missing for accurate modelling of the behaviour of the structure, although structural assessment is crucial in the reuse of any construction. This paper presents results from three bending tests up to failure, carried out on beams from a narrow-gauge railway viaduct designed by Hennebique and built in Belgium in 1904. They provide better understanding of the mechanisms of failure and reveal the main strengths and weaknesses of the typical Hennebique T-beam. The overlapping length of the rebars at the supports is found to be the crucial aspect, even if a large capacity of ductility is observed. Failure occurred owing to slipping of the upper rebars above the support area. This means that attention should be given to detailing. Consequently, localised structural strengthening with additional reinforcements is probably required when seeking to enhance the lifetime of these old reinforced concrete structures.