Structural Behavior of Prestressed RC Dapped Beam with Openings Strengthened Using CFRP Sheets

Abstract

This research examines the strengthening efficiency of prestressed concrete dapped end beam with opening under monotonic point load. The study concerns with the position of the opening relative to the dapped end, the shape of opening, as circle or square, in addition, the effect of CFRP strengthening around the opening. The experimental program consisted of testing nine scaled down prestressed concrete dapped end beam specimens with single opening near the dapped end. Beam specimens consisted of one control beam and the remaining eight beams classified into two groups. The first group contained four unstrengthened specimens, whereas the second group included beams with opening strengthened using CFRP sheets. A full wrapping configuration for the opening region was adopted in this research. The results presented the detrimental influence of the openings on the shear strength of the dapped beam and the additional strength achieved from strengthening. This study concludes that the shear strength of the prestressed dapped beam decreased by the presence of openings in the web with maximum reduction about 20% when the opening was located close the dapped end. Based on the test results, the strengthened beams recovered significant part of their original load carrying capacity. Generally, prestressed dapped beams regain a maximum of 92% of their strength when openings with different configurations and locations were strengthened with full CFRP wrap.