Simplified equation for estimating periods of vibration of concrete wall housing

As it is widely recognized, seismic design parameters used in most current codes are mainly intended for designing concrete walls in medium- or high-rise buildings. In low-rise concrete housing, thin walls with low concrete strength, web steel ratio smaller than the minimum ratio prescribed by codes, and in many cases, shear web reinforcement made of welded wire meshes are commonly used. In this paper, a simplified equation for estimating the period of vibration of low-rise concrete housing is proposed. The equation is based on response measured during shaking table tests of solid walls and walls with openings, on the results derived from conventional spectral analysis of ambient vibration tests, as well as on results obtained from mathematical models using the wide-column analogy and the finite element method. Statistical analysis of the ratios of predicted-to-measured periods demonstrated that predicted periods were very similar to those observed, and the scatter is also lower than in existing equations. The proposed equation is useful for seismic design, as well as for assessing the adequacy of available equations in current codes.