Sensitivity of the Strut Model for an RC infill-frame to the variations in the infill material properties

Extensive research has been carried out on the behaviour of infill-frames when laterally loaded. This paper focuses on the analysis of infill-frames using the equivalent strut modelling method. Even though several different strut models are available in the literature, recent studies have shown that it is not possible to apply one strut model to all infill-frame structures. This means that by changing properties of the infill-frame, the geometric properties of struts namely, width, location and number of struts, will also change. A finite element model at a micro level available from the literature has been used to perform a sensitivity analysis on an infill-frame by varying the material properties of the infill. Since the principal stresses in the panel, which are used to define the struts, change as the lateral drift increases, an optimal drift value is suggested for each analysis at which the geometric properties of the strut model can be determined.Based on the results of the sensitivity analysis, one strut model is proposed which is shown to be suitable for all of the cases considered in this study