Experimental study on reinforced stone beams
Résumé
Stone structures such as bridges, civil and worship buildings or monuments represent the largest part of the construction heritage in the world. They are indeed remarkably durable and earthquake resistant if they were correctly designed. Beside they also have very interesting environmental properties, notably in terms of life cycle analysis, so that stone has a good potential as building materials for modern architecture. The understanding of their mechanical behaviour is hence necessary to develop proper design methods for the prediction of displacements, crack opening or plastic failure in the sense of Eurocode or other modern design recommendations. The proposed article is dedicated to the study of an innovative system of reinforced stone beam in which the reinforcement is not used as a simple tie that overtakes the structure thrust but rather works with the stone together to build a system that resists vertical forces by bending. The study consists in an experimental program carried out on three beams made of dimension stones tested under four points bending. The beams are subjected to a small number of loading–unloading cycles to evidence hysteresis effects. Typical load–displacement curves are produced from data recorded by load cells, extensometers and strain gages measuring characteristic displacements, crack opening and strain in the reinforcement. Then a simple analytical model based on existing models for reinforced concrete is used to interpret the experimental results and by reverse analysis to identify some characteristics of the beams. Finally a short conclusion closes the paper on the potential of these structures for modern architecture and gives some perspectives of further investigations.