Abstract
The object of consideration is seismic design, and the subject of the study is the determination of the reduction coefficient. One of the important problems of earthquake-resistant design is to determine the effect of low-cycle fatigue of reinforced concrete on the reduction coefficient and determine its optimal value. This problem is not disclosed and is not specifically taken into account in the standards for earthquake engineering when determining the maximum bearing capacity of types of structures due to the lack of study of the issue. To solve the problem, a series of experimental studies were carried out on low-cycle fatigue of reinforced concrete bending elements and frame units. The range of results of the reduction coefficient values and the degree of influence of monocyclic fatigue on the properties of the reduction coefficient are obtained. A feature and characteristic of the results obtained is that the reduction coefficient Rμ depends on the nature of the hysteresis deformation pattern and the plastic life of structural elements estimated by the plasticity coefficient μ, which is significantly influenced by low-cycle fatigue manifested at peak accelerations of strong seismic impacts. The above test algorithm, the feature and characteristics of the results obtained made it possible to solve the problem under study. The results obtained are accepted for practical use in the action of seismic loads: on the calculation of strength taking into account new low-cycle coefficients, reduction coefficients for determining the spectra of design reactions and seismic loads, taking into account energy absorption. New reduction coefficients are proposed for determining the spectra of calculated reactions and seismic loads