The idea of strengthening the existing masonry infill walls of reinforced concrete (RC) frames has attracted many research groups in the last decade. The use of carbon fiber reinforced polymer (CFRP) strips along the diagonals of infills has become one major technique applied for this purpose. An experimental study conducted by the authors focused on the effect of aspect (height/width) ratio of hollow clay tile infills on the overall response attained by this strengthening methodology. Two different aspect ratios (HCT) were selected in the experimental study. However, a wider range of aspect ratios should also be investigated for design purposes. Therefore, a numerical model of the test frames are developed, which are validated by the experimental response curves. The basics of the numerical model that leads to a parametric study is the subject of this article. © (2013) Trans Tech Publications, Switzerland.