Characteristics of experimental ductility energy index of hybrid-CFRP reinforced concrete deep beams
Mahir M. Hason, Ammar N. Hanoon, Sarah Saleem, Farzad Hejazi, Ahmed W. Al Zand
Abstract
Abstract Although the ductility energy ratio ( $$\mu_{E}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>μ</mml:mi> <mml:mi>E</mml:mi> </mml:msub> </mml:math> ) of the reinforced concrete beam has been the topic of numerous study purposes and critical inquiry for the last decades, narrow consideration, especially in terms of reinforced concrete deep beams (RCDBs), is conducted to examine the ductility energy of hybrid-RC deep beams with various CFRP configurations. Growing the ductility of RCDB by CFRP reinforcement is significant in terms of shear resistance. Therefore, the objective herein is to explore the consequence of CFRP configurations (full side warped, 45° and 90° side stripes) on the ductility energy of RCDBs per two values of the shear span over depth proportion ( $$a/d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>a</mml:mi> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> </mml:mrow> </mml:math> ) of 1.0 and 1.75, and shear reinforcement ratios ( $$\rho_{v}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>ρ</mml:mi> <mml:mi>v</mml:mi> </mml:msub> </mml:math> ) of 0.0% and 0.4%. The experimental testing program included 12 RCDBs, three ordinaries (unstrengthen), and nine retrofitted with several CFRP configurations. The results show that the CFRP strengthened beams is presented a higher degree of increase in terms of mid-span deflection with respect to conventional beams. The ductility energy index ( $$\mu_{E}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>μ</mml:mi> <mml:mi>E</mml:mi> </mml:msub> </mml:math> ) increases with the increase of the shear reinforcement ratio ( $$\rho_{v}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>ρ</mml:mi> <mml:mi>v</mml:mi> </mml:msub> </mml:math> ). The dissipated energy demonstrated by strengthening beam with CFRP is from 45 to 80%, and it was higher than those of reference RCDBs. The energy absorption of RCDBs is improved due to the attendance of CFRP configurations of about 15% and 51% for $$a/d$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>a</mml:mi> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> </mml:mrow> </mml:math> proportion of 1.0 and 1.75, respectively, and for $$\rho_{v}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>ρ</mml:mi> <mml:mi>v</mml:mi> </mml:msub> </mml:math> of 0% and 0.4% are about 15% and 86% consecutively.