The influence of masonry infills with openings on the rotations of RC members of infilled frames at yielding
and ultimate under seismic loading is investigated. Fifteen 1/3-scale, single-story, single-bay frame specimens were tested
under reversed cyclic, quasi-static, horizontal loading up to a drift level of 40‰. The parameters investigated include the
shape, the size, the location of the opening and the infill compressive strength. Relative hinge rotation at the ends of the
beams and columns were calculated by a pair of displacement transducers placed on the surface of the frame members.
Based on the load against rotation envelope curves of each cross-section, the deformation at yielding, θy, and the ultimate
deformation capacity, θu, corresponding to a lateral force response equal to 85% of the maximum, were measured and
compared with the values given by FEMA reports. Consequently, a reduction factor is proposed for FEMA values.