Non-linear Behaviour of Infilled RC Frame

Abstract

The reinforced concrete (RC) infilled frame is very common in exercise. In general, only infill weight is considered in the design of the RC infilled frame, and the strength of masonry is ignored. However, the prominence of masonry infill on the seismic behaviour is highlighted during past earthquakes. Nowadays, applications of different types of masonry such as fly ash, and lightweight masonry in infill, are increasing due to their superior properties over the traditional clay brick masonry. The exact behaviour of the infilled RC frame during an earthquake cannot be predicted if the strength of infilled is ignored. A nonlinear static method i.e. pushover analysis for the seismic evaluation, is commonly used due to its simplicity and high accuracy. A typical four storey three bay plane infilled RC frame is considered in the present study to investigate efficacy of several formulas available in the literature for the modelling of infill employing pushover analysis method. In addition to that sensitivity analysis also conducted which revealed that the parameters, masonry wall width and masonry shear strength are significant that control the base shear at yield level. Significant decrease in the lateral stiffness is observed for a higher percentage of openings in the infilled. However, up to 5% of openings in infilled can be ignored due to its marginal change in the lateral strength of infill.