Advances in prestressed concrete bridges with external prestressing

External tendons are being used widely in prestressed concrete bridges. In this method of prestressing, the tendons are placed outside the concrete section. The development of this technology has led to tremendous advances in bridge engineering leading to innovative solutions with lightweight structures. One such example is the use of large eccentric external tendons, where the tendons are placed below or above the concrete girder. Using this concept, an innovative two span continuous girder bridge was developed in Japan. Another example is the development of composite bridges with corrugated steel webs. External tendons are used to provide the longitudinal prestressing in this kind of bridge. In addition to the above structural systems, the use of lightweight aggregates in externally prestressed concrete bridges have paved the way for lightweight bridges in the material context. This paper describes three bridge projects with external prestressing using the above innovative concepts, highlighting important design and construction issues.