Establishment of relationships for predicting the lateral drift demands of near-fault ground motions is one of the major challenges in earthquake engineering. Excessive lateral drifts caused by earthquake ground motions are the major causes of structural damage observed in structures. In this study, some of the fundamental characteristics of near-fault ground motions are examined. Response characteristics of elastic frame structures to near-fault ground motions are investigated. An approximate method for estimating the elastic ground story and interstory drifts for regular frame type structures is presented. Inelastic displacement demands imposed on elasto-plastic single degree of freedom (SDOF) systems subjected to near-fault ground are examined. Three equations for estimating the maximum lateral inelastic displacement demand from the maximum elastic displacement demand are established. Two of these equations relate the inelastic and elastic displacement demands through natural period and strength reduction factor. The third equation relates the inelastic and elastic displacement demands through the ratio of natural period to pulse period and the strength reduction factor. Efficiency of the natural period to pulse period ratio for estimating the inelastic displacement ratio is shown. Error statistics of the proposed equations are presented and compared with similar studies in the literature. According to the results, these equations can be used for quick and rough estimates of displacement demands imposed on regular elastic moment resisting frames and elasto-plastic single degree of systems.

Steel plate shear walls (SPSWs) are a lateral force resisting system consisting of thin infill steel plates surrounded by boundary frame members. The infill steel plates are allowed to buckle in shear and subsequently form diagonal tension field actions during earthquake events. Hysteretic energy dissipation of this system is primarily achieved through yielding of the infill plates. Conceptually, in a SPSW system with ideally rigid columns pinned to ground, the infill plates at different stories will yield simultaneously as a result of the lateral loads. However, when the columns become flexible, infill plate yielding may initially occur at one story and progressively spread into the other stories with increasing roof displacement. This research investigates the effect of column stiffness on infill plate yielding sequence and distribution along the height of steel plate shear walls subjected to earthquake forces. Analytical models are derived and validated for two-story SPSWs. Based on the derived model, probabilistic simulations are conducted to calculate the probability of achieving infill plate yielding in both stories before occurrence of a premature failure caused by excessive inter story drift at the initially yielded story. A total of three simulation methods including the Monte-Carlo method, the Latin Hypercube sampling method, and the Rosenblueth’s 2K+1 point estimate method were considered to account for the uncertain infill plate thickness and lateral force distributions in the system.The investigation is also extended to multi-story SPSWs. Three example six-story SPSWs are evaluated using the Rosenblueth's 2K+1 point estimation method which is identified to be most efficient from the simulation on two-story SPSWs. Moreover, the effectiveness of the column minimum moment of inertia required in the current code for achieving infill plate yielding at every story of SPSWs is evaluated.