Description
Infill masonry walls are one of the most common non-structural elements worldwide adopted to create external and internal partition walls in reinforced concrete (RC) frame structures. Both in the design of new RC frame buildings and in the assessment of the existing ones, it is common practice to neglect the presence of infill walls that are only considered as added masses and loads. However, as revealed by earthquakes, the performance of this type of building can be significantly affected by the presence of infill walls according to their type and distribution in the plane and along the height. In last decades, often vibration-based tests have been adopted to investigate in-situ the influence of the non-structural elements on the dynamic behavior of buildings. This paper discusses the usefulness of the dynamic characterization of buildings based on the use of ambient vibration tests at different phases of rehabilitation works to highlight the role of internal and external infill walls. The case study is an existing RC framed building designed for gravity loads and containing unreinforced masonry infill walls. Three ambient vibration tests, i.e., on the as built structure, after the demolishment of the internal partition walls and after the partial demolishment of the external infill walls, have been carried out. The 3D finite element model of the building has been successfully updated based on the global modes identified by the in situ tests, pointing out the important role of the non-structural components for this type of building. The experimental tests have also allowed the monitoring of the evolution of the building modal properties during the main phases of rehabilitation works.
