Assessment of seismic resistance of multi-storey buildings under seismic impacts on weak subsidence soils

Abstract

Under the influence of dynamic and static loads, the volumes of weak soils in the base change due to a decrease in porosity. In this regard, studies of the stability of the building under seismic influences, the bases of which are elastic-plastic layers, have been carried out. As a result of the research carried out in this paper, an equation of ground motion was obtained to determine the general angle of inclination of the building, taking into account the seismic impact characteristic of the construction site and the characteristics of the building itself. An increase in the risk due to the loss of stability of the base due to the possible slope of the building is shown. The mechanism of soil weakening, which leads to the overturning of buildings, is analyzed and justified. The parameters affecting the kinematic characteristics of buildings and structures are shown. It is determined that an elastic system consisting of a building and a base has one-way connections between the foundation and the base, which are removed under the influence of seismic forces in certain areas of the foundation sole, where the static load is insignificant. Removing the links causes a change in the rigidity of the system. The center of gravity and the center of mass are shifted by a certain distance, therefore, there are changing fluctuations. The range of vibrations in this case depends on the ratio of the natural frequencies of buildings and seismic waves. It is known that when a building under the influence of external forces receives a certain slope relative to the vertical axis, then there is a decrease in the load, a dependence is obtained to determine the load reduction coefficient. The paper considers a practical solution to the problem of stability on the example of a 50-meter building. Based on the general principles of earthquake-resistant construction in the calculation of overturning, several calculations of buildings were carried out using the initial data for frequent and weak impacts, moderate strength and rare strong impacts. The results of the research can be applied to the calculations of multi-storey and high-rise buildings built on weak deformable soils, along with other calculations that allow increasing seismic resistance.