AbstractLateral load-resisting structural members, such as piers, are often analyzed under one component base excitation. The influence of bidirectional shaking is accounted for by using a simplified 30% rule. During seismic shaking, piers are often subjected to bidirectional ground motion, which leads to a complex combination of biaxial moments. In this backdrop, a RC bridge pier has been analyzed under a set of bidirectionally applied near-field motions with forward directivity (FD) and fling-step characteristics. Bidirectional interaction under near-fault motion is observed to substantially amplify damage, particularly for a stiff system (30% and 45%–50% under FD and fling motions, respectively). A complex combination of bidirectional load paths may have also contributed to increased vulnerability. Additional studies have shown that pulses with fling-step characteristics may often be more detrimental than FD, at least for the first mode-dominated systems. The roles of important ground-motion parameters...