## 1 Introduction
The dynamic responses and failure modes of ordinary concrete and RAC specimens were compared and discussed by using the shaking table test on RAC frame-shear walls [25]. In general, recycled coarse aggregate is different from natural gallet and pebble aggregate, and its porosity is high, thereby resulting in high water absorption, large dry shrinkage and creep, and poor bond performance of the RAC. Considerable research on the mechanical properties, components, and structures of RAC have demonstrated that RAC shows similar mechanical properties to ordinary concrete and can be widely used in construction after rational design. The main load-bearingcomponents of RAC structures include recycled coarse aggregates, which were popularized during the construction of towns after the Wenchuan earthquake in 2008. Steel structure residences have the advantages of strong seismic resistance, high industrialization, recyclability, and reduced resource consumption and construction waste discharge. They are also among the residential structure systems preferred by developed countries at present. In addition to using steel to build steel structure residences, the material development and application technology of enclosure systems have also been assessed. This scenario is a technical problem for new building energy-saving materials and systems, and a social and economic development problem for factory construction of housing in terms of changing construction modes. [PERSON] et al. [26] and [PERSON] et al. [27] tested semi-rigid steel frame-filled concrete shear walls and determined that the energy dissipation of this composite structure mainly depends on the aggregate friction and occlusion between the cracks of filler walls and the yield of shear studs. The structure has multiple transmission paths of horizontal loads and a high safety reserve. [PERSON] et al. [28] and [PERSON] et al. [29; 30] conducted research on a steel-plate shear wall with a semi-rigid steel frame and found that the structure exhibits the advantages of semi-rigid joints with good rotation capability as well as energy absorption through the yield deformation of the steel plate. The hysteretic performance is stable and characterized by the simplified construction and efficient utilization of materials. [PERSON] et al. [31] conducted an experimental study on steel frames with replaceable reinforced concrete walls. Other tests, such as tests on steel frames with fabricated autoclaved lightweight concrete panels, composite lightweight walls, and light-gauge steel stud walls, were conducted under horizontal low cyclic loading [32; 33; 34]. Prefabricated construction systems have the advantages of fast construction, stable quality, and energy saving, along with being an environmentally friendly and sustainable development technology. In this study, two aspects of improvements were considered on the basis of the structure of steel frames filled with concrete shear walls as proposed by the previous scholars. On the one hand, the RAC concrete was used to replace the ordinary concrete, and concrete shear walls made of recycled coarse aggregate were introduced into the steel frame structure. The walls bore the horizontal loads as the main lateral resisting components of the structure when they functioned as the enclosure, thereby providing a new idea for popularizing and applying RAC in steel structure residences. On the other hand, the prefabricated connection between steel frames and concrete shear walls was also considered to facilitate the rapid construction of the project and the timely replacement of the damaged walls. Therefore, the structure of steel frames with infilled RACSWs (SFIRACSWs) is proposed in this paper, and tests on SFIRACSWs were conducted under horizontal low cyclic loading. The effect of two composite forms of steel frames and RACSWs (namely, infilled cast-in-place and infilled prefabricated) on the mechanical behavior of SFIRACSWs is discussed.