Analytical determination of damage limit values in reinforced concrete structures

In the Regulation on Buildings to be Applied in Earthquake Regions that is currently in force (DBYBHY-2007) and in the Turkish Building Seismic Code (TBDY, 2018) that will be going into force in 2019, the damage limits are based on the strain capacity of steel and concrete. However, the moment-curvature calculations based on the assumption that the plane sections remain after the deformation are still problematic for reinforced concrete shear walls, where the section depth is too large for this assumption to be valid. Therefore, a comprehensive study is required for the evaluation of the adequacy of the proposed damage limit values. This study is based on numerical method due to labor and time required in the experimental works, which only permits to test the effect of limited number parameters, the inadequacy of experimental setups in reflecting the actual boundary conditions and difficulties in testing full size specimens. By employing a finite element modeling tool (ANSYS) that is well calibrated using available test results, the relationship between the displacement, the section rotation and curvature, the concrete and reinforcement strains at the section of the reinforced concrete shear wall elements is examined. In order to evaluate the reliability of damage limits available in codes for shear wall members, the limits in ASCE/SEI 41, Eurocode 8, DBYBHY (2007), Turkish Building Seismic Code published in draft (TBDY-2016) and TBDY (2018) are examined and the existing limits were compared with the limits derived from finite element with analysis. In the light of the obtained results, more refined modeling parameters and acceptance criteria for reinforced concrete shear walls are proposed.