Investigation of flexible joints between infill wall and frame in reinforced concrete buildings

Lateral stiffness provided by infill walls is generally neglected in building design. Infill walls, which are only included in the calculations as dead load, significantly affect the lateral resistance, stiffness and energy dissipation of the frames. The existence of these effects, which are not foreseen in the design, are supported by both the experimental studies in the literature and the infill wall damages observed after the earthquakes. It is an important problem to reflect the infill wall effects to the application as designed. In order to minimize the problems caused by infill walls made of brittle material, in addition to various methods tried in the literature, the 2018 Turkish Building Earthquake Code introduced the option of applying flexible joints between infill walls and insulating them from the frame. In this study, the solution of isolating the infill walls from the load-bearing frames has been adopted. In this context, together with the flexible joint detail presented as an example in 2018 Turkish Building Earthquake Code, three different flexible joint details were designed. Flexible joint details applied to reinforced concrete frames produced in 2/3 scale were examined experimentally and numerically, and their in-plane behavior was compared with bare and traditionally infilled frames. Contrary to the full-frame behavior, which loses its lateral resistance significantly in small drifts, it was observed that the frames with flexible connections behaved close to the bare frame in the small drifts and maintained its lateral resistance without being damaged until the extreme drifts.