The Joigny Bridge: An Experimental High Performance Concrete Bridge
The French Ministry of Public Works and the National Project on New Concretes team agreed to build an experimental bridge using high performance concrete. The bridge was built crossing the river Yonne near the town of Joigny, approximately 150 km southeast of Paris. The bridge was designed according to the French codes Beton Precontraint aux Etats Limites (BPEL, Limit-States Design of Prestressed Concrete) and Beton Arme aux Etats Limites (BAEL, Limit-States Design of Reinforced Concrete). These codes have been upgraded to incorporate 60 MPa concretes since they previously dealt only with concrete strengths up to 40 MPa. The use of these codes, which include different safety factors, led to an actual maximum compressive stress of 30 MPa in the lower fiber to the central span's mid-section during the last stages of prestressing. Monitoring instruments were built into the bridge to verify the assumptions in the calculations, to check its long-term behavior, and to assess its durability compared to ordinary bridges.