Document Type : Research Note
An extensive investigation is conducted on experimental data to improve modification factors of masonry infills. For this, available experimental data are classified based on the frame and infill materials. Then a sensitivity analysis is carried out for the effective parameters on the m-factor, including relative stiffness of infill to the frame, the material of infill or frame, aspect ratio, etc. To calculate m-factors of specimens, both the backbone and the envelope curves of the hysteresis curves, proposed in ASCE41-06 and ASCE41-13, respectively, are applied. The obtained results confirmASCE41-13 for giving more conservative m-factor values. Sensitivity analysis shows that infill m-factors highly depend on the infill and frame materials, rather than the infill aspect ratio and relative stiffness of the frame to the infill. Finally, some values are proposed for m-factors of infill panels, made of clay brick or clay tile, surrounded by steel or concrete frames.