Abstract
Reinforced concrete (RC) beams with light transverse reinforcement are vulnerable to shear failure during seismic response. In order to prevent brittle shear failures at beam plastic hinge regions of earthquake-resistant structures, the Turkish Earthquake Code and ACI318 require the use of sufficient transverse reinforcement to resist the total expected shear demand. These codes tend to be excessively conservative and, in some cases, the contribution of the concrete to the shear strength is neglected. The aim of this study is to investigate the contribution of concrete to shear strength of RC beams failing in shear experimentally. The beams were tested under monotonically increasing reversed cyclic loading to determine the concrete contribution to shear strength. It is observed that the concrete contribution to the shear strength at ultimate state ranges from 18% to 69% of the ultimate strength.
Highlights
Extensive studies have been carried out in the past two decades to investigate the shear capacity degradation and the concrete contribution to the shear strength of reinforced concrete (RC) members, as a function of ductility demand (Aschheim, Moehle 1992; Priestley et al 1994; Lehman et al 1996; ATC-32 1996; MartınPerez, Pantazopoulou 1998; Sezen, Moehle 2004), deflection capacity (Lee, Watanabe 2003), drift ratio (Elwood, Moehle 2005) and rotation capacity (Arslan 2005)
It can be concluded that the transverse reinforcement becomes more effective with the increasing load after the shear cracks extend up to mid-height of the beam (Fig. 7)
The degradation of shear strength and stiffness in RC beams under increasing reversed cyclic loading is primarily due to the fact that crack opening are unable to close in the beams H16S155 and H22S250 because of the yielding of transverse reinforcement across the beams;
Summary
Extensive studies have been carried out in the past two decades to investigate the shear capacity degradation and the concrete contribution to the shear strength of reinforced concrete (RC) members, as a function of ductility demand (Aschheim, Moehle 1992; Priestley et al 1994; Lehman et al 1996; ATC-32 1996; MartınPerez, Pantazopoulou 1998; Sezen, Moehle 2004), deflection capacity (Lee, Watanabe 2003), drift ratio (Elwood, Moehle 2005) and rotation capacity (Arslan 2005). In order to prevent shear failures at beam plastic hinge regions of earthquake-resistant structures, European design codes, such as the CEB-FIP Model Code 92 (1991) and Eurocode 2 (2004), do not take into account the contribution of concrete in certain cases. Elmenshawi et al (2009) conducted experiments on elements constructed with different concrete strengths (30Á175 MPa) tested under load reversals in order to investigate the shear behaviour of flexural plastic hinges. Park et al (2011) tested 10 RC columns with varying axial force ratio and shear reinforcement ratio under monotonic and reversed cyclic loading and found out that the concrete contribution to shear resistance in the plastic hinge region decreased with the increasing axial load. Park et al (2011) tested 10 RC columns with varying axial force ratio and shear reinforcement ratio under monotonic and reversed cyclic loading and found out that the concrete contribution to shear resistance in the plastic hinge region decreased with the increasing axial load. Chao and Loh (2009) proposed a biaxial hysteretic model to take into account the hysteretic characteristics of strength and stiffness degradation, pinching and biaxial interaction and used the test data of six RC columns to validate the model. Zhang et al (2011) proposed a coupled hysteretic model in order to simulate the shear-flexure interactive behaviour of columns and the accumulated material damage during loading reversals, including pinching, strength deterioration, and stiffness softening, since the axial-shear-flexure interaction in columns considerably affects the strength, stiffness
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
