Square RC columns confined with non-laminated CFRP straps

ABSTRACT

The enhancement of strength and ductility due to external confinement of reinforced concrete columns having a square or rectangular cross section is usually limited because a significant portion of the cross section remains unconfined. In this paper an innovative method is presented to confine square reinforced concrete columns using non-laminated CFRP straps. The CFRP straps can be either unstressed at the beginning or pre-stressed. Tests were carried out on three medium scale columns (2.0 m high with a cross section of 0.4 m x 0.4 m). The first column was the unconfined reference column, the second column was confined with prestressed non-laminated CFRP straps and the third column was confined with non pre-stressed non-laminated CFRP straps. The test results show no or only a small increase in strength but a significant increase in the deformation capacity of the confined columns with respect to the unconfined column.