Investigation of the infill wall effect on the dynamic behaviour of RC frames

Abstract

The simplicity of construction and economic reasons have made the infilled frame one of the most preferred structural form for reinforced concrete (RC) frame buildings around the world. For these reasons, the usage of infill walls with reinforced concrete frames increased rapidly over the past decades. On the other hand, although the reinforced concrete frame-infill systems are commonly used throughout the world, the infill is rarely included in the numerical analysis of the structures. For this reason the main goal of this study is to investigate, obtain and compare the dynamic characteristics such as natural frequencies, mode shapes and damping ratios of RC frames with and without infill wall by using classic vibration test results within elastic limit. In addition, the contribution of infill wall to the RC frame behavior for the small strain level is also the target of this paper. For this purpose, full scaled, one bay and one storey RC frames with and without infill wall are constructed and tested.Enhanced Frequency Domain Decomposition technique is used in order to attain the experimental dynamic characteristics of the frames. The results from tests showed that the forced vibration test measurements are sufficient and satisfying to identify the dynamic properties of the RC frames for both with and without infill walls. Furthermore, addition of infill wall to the bare frame does not have an important effect on the dynamic characteristics of the system for small strain level. On the other hand, it is shown that the application of plaster to the infill wall changes the dynamic behavior of the system significantly even for such a so small forces used in this study.