Introduction. The Necessity of constructing high-rise buildings in dense urban development in the 1960s led to the introduction of a new structural system of high–rise buildings with rigid core. One of its varieties is the suspended structural system, which has been implemented in many buildings around the world. In addition to the architectural advantages of the suspended buildings, the system has design features associated with significant flexibility of the load-bearing elements. This feature of high-rise buildings makes allows reducing the seismic load on structures. The technical implementation of the suspended floors has some difficulties. The calculation methods did not allow us to show the behavior of suspended structures under dynamic influences. This was an obstacle to the use of a suspended system in the construction of high-rise buildings in seismically active areas in the past. Another approach to providing seismic protection for high-rise buildings is the installation of dynamic vibration dampers. This requires the insertion of additional massive elements into the structure of the building, occupying its internal space. Suspended structures in buildings with a load-bearing core can potentially act as elements of dynamic vibration dampers. Modern methods of calculating mathematical models and computing complexes allow us to verify this assumption. These methods are capable of performing complex tasks in the field of dynamic linear and nonlinear vibrations, in particular vibrations of suspended structures of buildings. This article presents a new design solution for a suspended building with rigid core. An assessment of the influence of the engineering parameters of the suspended part of the building on its seismic resistance is given.

Materials and methods. For evaluation of the effectiveness of the proposed building structural solution in the conditions of seismic impact, numerical modeling of the building in the LIRA software package in a stepwise nonlinear setting was performed.

Results. Movements and accelerations of a suspended building during an earthquake depend on the magnitude of the longitudinal stiffness of the elastic links and the mass of the upper suspended floor block. The rational parameters of suspended structures have been determined to reduce the oscillations of the building.

Conclusions. A change in the mass of suspended floors and the rigidity of the connections between the elements of suspended building can lead to a decrease in displacements and accelerations of structures and damping system vibrations. Further research can be devoted to the analytical determination of the optimal parameters of suspended structures that ensure the dispersion of seismic action energy.

The article describes a problem of uncertainty modeling of statistical data in the problems of structural reliability analysis. There are elements of subjectivity in decisions making about the type of distribution of a random variable and its parameters on the analysis of the results of numerical experiments and real tests of control samples of steel on yield strength. As an alternative to the cumulative distribution function it is proposed to use p-box as a model of a random variable. The new type of a p-box is proposed on the basis of the Dvoretzky–Kiefer–Wolfowitz inequality, which allows to form the area of possible cumulative distribution functions without base on classical probability distributions. By the example of reliability analysis of a steel structural element, the variants of using different p-boxes are shown depending on the available statistical data. The probability of no-failure is presented in interval form based on p-boxes. If the result of reliability analysis by the lower boundary does not allow to make a decision about the safety level of a structural element, two options are possible: to reduce the uncertainty of the data by conducting additional statistical researches or to increase the cross-sectional area of the structural element.  

The widespread use of high-rise buildings was caused by the growing population of cities and the lack of land. As practice shows, the structural system of high-rise buildings with a load-bearing core is one of the most reliable. A variety of such buildings are buildings with suspended structures. This structural system has found application in many high-rise buildings around the world, including in seismically active areas. At the same time, such a constructive solution is rarely found in Russia. We have no recommendations on the use of this structural system, and there is also no information about the behavior of suspended structures with high seismic activity. The greatest interest in the study of buildings with a load-bearing core occurred in the 80s – 90s of the 20th century. It is worth mentioning a number of important advantages of the considered constructive system. First of all, these structures have significant flexibility, which leads to an increase in the natural period of oscillations and a decrease in the seismic load on the load-bearing elements. In some cases, suspended structures of buildings with a load-bearing core act as dynamic absorbers. This makes it possible to ensure the stability and reliability of the entire building without the use of special devices. This article presents the results of some studies conducted to use a structural system with a load-bearing core and suspended floors in seismic construction areas.

There are many approaches to ensuring the stability of high-rise buildings to seismic impacts. Among them, it is worth noting the use of suspended structures. This approach makes it possible to reduce the loads in load-bearing structures caused by dynamic influences. The effectiveness of the use of suspended structures in earthquake-resistant construction was confirmed by studies of the behavior of such objects in earthquake conditions. The development of computer systems allowed us to unlock the potential of using suspended structures in seismically dangerous areas. However, the engineering community has not yet come to an unambiguous solution to the problem of significant displacements of suspended ceilings during low-frequency seismic impacts. The question of ensuring the stability of the core structures of the building also remains open. Proposals for solving these problems, as well as the supporting structures of suspended high-rise buildings themselves, are diverse. This article discusses the main existing and promising design solutions that provide earthquake resistance of high-rise buildings with suspended structures. The results of computational studies of these design solutions are given in the article