Swiss Federal Roads Office Guidelines for Integral Bridges

Abstract

Integral concrete bridges have a long-lasting tradition in Switzerland. In particular, during the main construction period of the national motorway network (1960–1985), numerous jointless reinforced and prestressed concrete bridges were built. Based on this experience, and because of the often unsatisfactory long-term behaviour of expansion joints, the Guidelines of the Swiss Federal Roads Office (FEDRO), edition 1990, established as a general rule that expansion joints be avoided for bridges with lengths up to a range of 30 … 60 m. As a consequence, integral and semi-integral concrete bridges have become well established construction types in Switzerland. In effect, today more than 40% of the existing bridges on the FEDRO network are (semi-)integral structures, a considerable amount of them even exceeding the stipulated maximum bridge length. The Swiss experience with integral bridges is mainly positive, both in terms of construction and maintenance. Thus, it seems appropriate to potentiate their construction and extend their range of application. Following this aim, in the current revision of the FEDRO Guidelines, the design provisions for integral bridges have been substantially refined and extended to allow for wider applications, including specific guidance for semi-integral bridge ends.