FLEXURAL STRENGTHENING OF REINFORCED CONCRETE BEAMS USING EXTERNAL UNBONDED STEEL BARS

Document Type : Original Article

Authors

1 Materials Engineering Dept., Faculty of Eng., Zagazig University, Zagazig, EGYPT

2 Housing and Building Research Center, Cairo, Egypt

Abstract

The use of externally unbonded steel rods for strengthening beams in flexure was proposed as a
new technique recently. This technique has advantages in speed and simplicity of installation over
other established strengthening techniques. It was shown that the tectuuque could provide useful
enhancements in load capacity in all but heavily reinforced cross-sections. The present work aims
to further investigation of this developed technique. Factors such as the number of deflectors used
and the ratio of external to internal reulforcement areas were considered. Results showed that an
increase in the ultimate strength and an increase in the stiffness were obtained using the EUR
method while maintaining the traditional ductility behavior of RC beams. This gain in strength and
stilkess increased as the ratio of external to internal reinforcement areas or the umber of deflectors
increased. However, a well protecting method should be provided to give the external
reinforcement the aimed durability requirements.

Keywords