Fiber-hinge modeling of engineered cementitious composite flexural members under large deformations

Engineered cementitious composites (ECC) and other ductile cement-based materials have emerged as alternative materials to traditional concrete to improve the damage resistance, deformation capacity, and energy absorption capacity of structures in seismic applications. Developing computationally efficient numerical models and simulation techniques to predict the nonlinear response of ductile concrete materials can improve the engineering community's understanding of the performance of structures using these emerging materials. In this study, a numerical modeling strategy was developed, calibrated, and evaluated that can capture the cyclic response of reinforced ECC components under lateral load reversals at high deformations including component failure due to reinforcement fracture. A fiber-based lumped-plasticity model was adopted to simulate the non-linear response of reinforced ECC components. A simple expression for plastic-hinge length was developed to predict the force-deformation response and deformation associated with reinforcement fracture. Inaccuracies in the initial stiffness and cyclic response were mitigated by calibrating the rotational stiffness of an elastic spring and cyclic degradation parameters of a steel material model. The proposed modeling strategy was evaluated on 18 specimens using different cyclic deformation histories and reinforcement ratios. The modeling approach was compared to experimentally determined lateral strength, energy dissipation, deformation capacity, and longitudinal reinforcement strains to assess the accuracy of the strategy. This research provides a method to simulate the performance of ductile cement-based materials under large deformations, including collapse, and will improve the performance-based earthquake engineering analysis techniques for structures using ductile cementitious materials.