Reinforced concrete (RC) frames are widely used around the world due to the clear load path, diverse plan layouts and satisfactory economic performance they provide. However, recent seismic hazard investigations involving both experimental and numerical analyses have demonstrated that this kind of structure system is prone to soft-story mechanism. The mechanism may lead to collapse, resulting in large casualties and economic losses (Doǧangün, 2004; Goulet et al., 2007; Haselton et al., 2010; Zhao et al., 2009). In soft-story mechanism, deformation is mostly concentrated in a single story, which results in poor structural behaviors (e.g., overall ductility, energy dissipation). Plastic hinges are formed at the ends of columns, rather than beams. Moreover, even though a “strong column – weak beam” design philosophy is stipulated in most seismic design codes (CEN, 2004; ACI Committee 318, 2008; GB50011, 2010), soft-story mechanism may still occur due to several factors, including variations in material properties and the effect of a slab′s composition (e.g., thickness, strength). Even though RC frames may remain standing after an earthquake, excessive residual drift and severe damage to critical components make it diffi cult to retrofi t, thus need to be demolished. Rapid societal developments have increased the urgency of achieving earthquake resilience (Bruneau et al., 2003). To realize this goal, seismic damage should be restricted to locations where critical load paths are not greatly affected. Specifi cally, in an RC frame structure, which may suffer from soft-story mechanism under severe earthquakes, a continuous component is expected to achieve uniform deformation along the height. Thus, a continuous component causes the RC frame to behave more predictably. It may also improve effi ciency as well as facilitate the design of energy-dissipation devices. In the study presented here, an infi lled rocking wall is proposed as the continuous component in an RC frame structure. The structure system is therefore referred to as an “infi lled rocking wall frame.” The rocking wall is described as “infi lled” because it is built inside the frame, rather than outside of it. In conventional RC frames, infi lled walls are mostly constructed with lightweight blocks, and functionalize as nonstructural partition components that undertake only self-weight. In design, infi lled walls are represented as distributed loads on frame beams. Infi lled rocking walls, however, are critical structural components in an infi lled rocking wall frame. As the deformation mode is changed by the wall, interaction forces between the frame and the wall are large. For this reason, rocking walls should either be constructed with stiff blocks or cast directly from reinforced concrete. The infi lled wall is described as “rocking” because the wall is not fi xed to the foundation and can rotate around the bottom. As illustrated in Fig. 1, an infi lled rocking wall is constructed with reinforced concrete continuously along the height of an RC frame. Frame columns adjacent to the wall are cut off at the bottom to allow uplift. With rocking characteristics, selfweight and vertical loads in the wall can be converted to self-centering forces that minimize residual drift. An infi lled rocking wall provides a feasible approach to retrofi tting an existing RC frame, which would otherwise be prone to soft-story mechanism in severe earthquakes due to a lack of uniform stiffness along the height.