Supresión de juntas como mejora de la conservación en viaductos de tableros isostáticos

Suppresion of joints as a system for improving maintenance in viaducts of simply supported decks

Transverse joints in bridge decks are one of the most problematic aspects of suck structures from the point of view of maintenance and conservation. The difficulty of assuring the joint watertightness results on a more or less permanent presence of humidity on the deck itself and on the support platforms of butresses or piers. This situation is quantitatively more problematical in the case of viaducts with simply supported decks, due to their high numnber of ransverse joints, specially it they were designed and built a few years ago, before generalizing the solution of continuous compression top slab. This paper prsents the operation carried out in La Jarosa viaduct as a contribution to solve this problem. Six of the nine original transverse joints of the bridge were remobed. A careful study was previously made, includin g a detailed analysis of the new situation of bearings, piers and foundations originated with the new continuous compression slab. Taking into account these results it was decided to lift the bridge decks before removint the joints, in order to eliminate the bearings permanent deformations induced by temperature changes and creep long-term effects. Finally, bearings were substituted during the lifting process, since the original elements had suffered a significant deterioration. Details on this lifting, on the laboratory tests carried out on old and new bearings, and on the execution process of the new continuous compression slab are also presented.