Strengthening of Prestressed Concrete Composite Beams Using External Prestressed Stirrups

摘要

align="left">Strengthening of older bridges designed for relatively light loading and traffic is necessary in many places around the world. This paper presents experimental results on the use of external prestressed? stirrups to improve the shear strength and concrete-to-strand bond strength of pretensioned composite beams. Five beams were tested under stationary static loads until failure. The basic unstrengthened? beam showed a very dramatic shear failure. The strengthened beams with external prestressed stirrups, however, performed well, even with very short strand embedment lengths. External prestressed? stirrups considerably increased the shear capacity of the strengthened beams. Also, when prestressed to adequate levels, the stirrups allowed the development of the flexural capacity of the beams with? strand embedment lengths as short as 100 times the? strand diameter.