Experimental Monitoring of the Joigny Bridge
High strength concretes and very-high-strength concretes are currently the subject of many researches. However, most of these researches are aimed at investigation of the materials rather than analysis of the structures built with the concretes. This is why a structure such as the Joigny bridge is of special interest of research in this area. It was decided, as part of the "Voies Nouvelles du materiau Beton" (New Ways for Concrete) National Project, that this bridge would be monitored experimentally, by the Laboratoire Central des Ponts et Chaussees and the Autun Regional Laboratory jointly. During the casting of concrete, the free surface of fresh concrete remained practically horizontal. So, a segregation phenomenon could have happened, like in a river where coarse materials remain near the source, and fine materials flows downstream. The consequence of the segregation process is a scattering of the compressive test values, which actually occured in Joigny bridge.