Seismic Damage Analysis of Reinforced Concrete Frame Using the Force Analogy Method

To meet the requirements of performance-based earthquake engineering, the influence of damage should be considered when conducting a structural performance assessment. In recent years, significant effort has gone toward developing accurate and efficient damage models for seismic damage analysis. In this paper, a framework for seismic damage analysis of RC frame structures considering stiffness degradation is established based on the force analogy method (FAM). A damaged hinge (DH) model, which is located at the ends of columns and beams, is proposed for modeling damage behavior owing to concrete cracking. The DH, together with the plastic hinge (PH), arising from structural materials and presented in prior research on the FAM, forms a complete inelastic mechanism including stiffness degradation behavior for RC frame structures. As damage effect is implemented by introducing the damage indexes as internal variables, the real-time structural performance and damage level can be evaluated during the computation process. Additionally, because only initial stiffness is used throughout the dynamical computation analysis, the usage of the state space formulation (an outstanding advantage of the FAM) is retained and makes the real-time damage analysis more accurate, efficient, and stable. The inelastic mechanism, which takes into account the damage effect on the stiffness degradation behavior in the FAM, is verified against experimental data, and the proposed method is applied in a RC frame structure to demonstrate its potential and efficiency on the seismic damage analysis. (C) 2013 American Society of Civil Engineers.